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dotfiles/gdb/.gdbinit-gef.py

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added gdb
2023-07-24 20:53:54 +02:00
#######################################################################################
# GEF - Multi-Architecture GDB Enhanced Features for Exploiters & Reverse-Engineers
#
# by @_hugsy_
#######################################################################################
#
# GEF is a kick-ass set of commands for X86, ARM, MIPS, PowerPC and SPARC to
# make GDB cool again for exploit dev. It is aimed to be used mostly by exploit
# devs and reversers, to provides additional features to GDB using the Python
# API to assist during the process of dynamic analysis.
#
# GEF fully relies on GDB API and other Linux-specific sources of information
# (such as /proc/<pid>). As a consequence, some of the features might not work
# on custom or hardened systems such as GrSec.
#
# Since January 2020, GEF solely support GDB compiled with Python3 and was tested on
# * x86-32 & x86-64
# * arm v5,v6,v7
# * aarch64 (armv8)
# * mips & mips64
# * powerpc & powerpc64
# * sparc & sparc64(v9)
#
# For GEF with Python2 (only) support was moved to the GEF-Legacy
# (https://github.com/hugsy/gef-legacy)
#
# To start: in gdb, type `source /path/to/gef.py`
#
#######################################################################################
#
# gef is distributed under the MIT License (MIT)
# Copyright (c) 2013-2022 crazy rabbidz
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import abc
import argparse
import ast
import atexit
import binascii
import codecs
import collections
import configparser
import ctypes
import enum
import functools
import hashlib
import importlib
import importlib.util
import inspect
import itertools
import os
import pathlib
import platform
import re
import shutil
import site
import socket
import string
import struct
import subprocess
import sys
import tempfile
import time
import traceback
import warnings
from functools import lru_cache
from io import StringIO, TextIOWrapper
from types import ModuleType
from typing import (Any, ByteString, Callable, Dict, Generator, Iterable,
Iterator, List, NoReturn, Optional, Sequence, Set, Tuple, Type,
Union)
from urllib.request import urlopen
GEF_DEFAULT_BRANCH = "main"
GEF_EXTRAS_DEFAULT_BRANCH = "main"
def http_get(url: str) -> Optional[bytes]:
"""Basic HTTP wrapper for GET request. Return the body of the page if HTTP code is OK,
otherwise return None."""
try:
http = urlopen(url)
return http.read() if http.getcode() == 200 else None
except Exception:
return None
def update_gef(argv: List[str]) -> int:
"""Try to update `gef` to the latest version pushed on GitHub main branch.
Return 0 on success, 1 on failure. """
ver = "dev" if "--dev" in argv else GEF_DEFAULT_BRANCH
latest_gef_data = http_get(f"https://raw.githubusercontent.com/hugsy/gef/{ver}/scripts/gef.sh")
if not latest_gef_data:
print("[-] Failed to get remote gef")
return 1
with tempfile.NamedTemporaryFile(suffix=".sh") as fd:
fd.write(latest_gef_data)
fd.flush()
fpath = pathlib.Path(fd.name)
return subprocess.run(["bash", fpath, ver], stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL).returncode
try:
import gdb # type:ignore
except ImportError:
# if out of gdb, the only action allowed is to update gef.py
if len(sys.argv) >= 2 and sys.argv[1].lower() in ("--update", "--upgrade"):
sys.exit(update_gef(sys.argv[2:]))
print("[-] gef cannot run as standalone")
sys.exit(0)
GDB_MIN_VERSION = (8, 0)
GDB_VERSION = tuple(map(int, re.search(r"(\d+)[^\d]+(\d+)", gdb.VERSION).groups()))
PYTHON_MIN_VERSION = (3, 6)
PYTHON_VERSION = sys.version_info[0:2]
DEFAULT_PAGE_ALIGN_SHIFT = 12
DEFAULT_PAGE_SIZE = 1 << DEFAULT_PAGE_ALIGN_SHIFT
GEF_RC = (pathlib.Path(os.getenv("GEF_RC", "")).absolute()
if os.getenv("GEF_RC")
else pathlib.Path().home() / ".gef.rc")
GEF_TEMP_DIR = os.path.join(tempfile.gettempdir(), "gef")
GEF_MAX_STRING_LENGTH = 50
LIBC_HEAP_MAIN_ARENA_DEFAULT_NAME = "main_arena"
ANSI_SPLIT_RE = r"(\033\[[\d;]*m)"
LEFT_ARROW = " ← "
RIGHT_ARROW = " → "
DOWN_ARROW = "↳"
HORIZONTAL_LINE = "─"
VERTICAL_LINE = "│"
CROSS = "✘ "
TICK = "✓ "
BP_GLYPH = "●"
GEF_PROMPT = "gef➤ "
GEF_PROMPT_ON = f"\001\033[1;32m\002{GEF_PROMPT}\001\033[0m\002"
GEF_PROMPT_OFF = f"\001\033[1;31m\002{GEF_PROMPT}\001\033[0m\002"
PATTERN_LIBC_VERSION = re.compile(rb"glibc (\d+)\.(\d+)")
gef : "Gef"
__registered_commands__ : Set[Type["GenericCommand"]] = set()
__registered_functions__ : Set[Type["GenericFunction"]] = set()
__registered_architectures__ : Dict[Union["Elf.Abi", str], Type["Architecture"]] = {}
__registered_file_formats__ : Set[ Type["FileFormat"] ] = set()
def reset_all_caches() -> None:
"""Free all caches. If an object is cached, it will have a callable attribute `cache_clear`
which will be invoked to purge the function cache."""
for mod in dir(sys.modules["__main__"]):
obj = getattr(sys.modules["__main__"], mod)
if hasattr(obj, "cache_clear"):
obj.cache_clear()
gef.reset_caches()
return
def reset() -> None:
global gef
arch = None
if "gef" in locals().keys():
reset_all_caches()
arch = gef.arch
del gef
gef = Gef()
gef.setup()
if arch:
gef.arch = arch
return
def highlight_text(text: str) -> str:
"""
Highlight text using `gef.ui.highlight_table` { match -> color } settings.
If RegEx is enabled it will create a match group around all items in the
`gef.ui.highlight_table` and wrap the specified color in the `gef.ui.highlight_table`
around those matches.
If RegEx is disabled, split by ANSI codes and 'colorify' each match found
within the specified string.
"""
global gef
if not gef.ui.highlight_table:
return text
if gef.config["highlight.regex"]:
for match, color in gef.ui.highlight_table.items():
text = re.sub("(" + match + ")", Color.colorify("\\1", color), text)
return text
ansiSplit = re.split(ANSI_SPLIT_RE, text)
for match, color in gef.ui.highlight_table.items():
for index, val in enumerate(ansiSplit):
found = val.find(match)
if found > -1:
ansiSplit[index] = val.replace(match, Color.colorify(match, color))
break
text = "".join(ansiSplit)
ansiSplit = re.split(ANSI_SPLIT_RE, text)
return "".join(ansiSplit)
def gef_print(*args: str, end="\n", sep=" ", **kwargs: Any) -> None:
"""Wrapper around print(), using string buffering feature."""
parts = [highlight_text(a) for a in args]
if buffer_output() and gef.ui.stream_buffer and not is_debug():
gef.ui.stream_buffer.write(sep.join(parts) + end)
return
print(*parts, sep=sep, end=end, **kwargs)
return
def bufferize(f: Callable) -> Callable:
"""Store the content to be printed for a function in memory, and flush it on function exit."""
@functools.wraps(f)
def wrapper(*args: Any, **kwargs: Any) -> Any:
global gef
if gef.ui.stream_buffer:
return f(*args, **kwargs)
gef.ui.stream_buffer = StringIO()
try:
rv = f(*args, **kwargs)
finally:
redirect = gef.config["context.redirect"]
if redirect.startswith("/dev/pts/"):
if not gef.ui.redirect_fd:
# if the FD has never been open, open it
fd = open(redirect, "wt")
gef.ui.redirect_fd = fd
elif redirect != gef.ui.redirect_fd.name:
# if the user has changed the redirect setting during runtime, update the state
gef.ui.redirect_fd.close()
fd = open(redirect, "wt")
gef.ui.redirect_fd = fd
else:
# otherwise, keep using it
fd = gef.ui.redirect_fd
else:
fd = sys.stdout
gef.ui.redirect_fd = None
if gef.ui.redirect_fd and fd.closed:
# if the tty was closed, revert back to stdout
fd = sys.stdout
gef.ui.redirect_fd = None
gef.config["context.redirect"] = ""
fd.write(gef.ui.stream_buffer.getvalue())
fd.flush()
gef.ui.stream_buffer = None
return rv
return wrapper
#
# Helpers
#
def p8(x: int, s: bool = False, e: Optional["Endianness"] = None) -> bytes:
"""Pack one byte respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.pack(f"{endian}B", x) if not s else struct.pack(f"{endian:s}b", x)
def p16(x: int, s: bool = False, e: Optional["Endianness"] = None) -> bytes:
"""Pack one word respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.pack(f"{endian}H", x) if not s else struct.pack(f"{endian:s}h", x)
def p32(x: int, s: bool = False, e: Optional["Endianness"] = None) -> bytes:
"""Pack one dword respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.pack(f"{endian}I", x) if not s else struct.pack(f"{endian:s}i", x)
def p64(x: int, s: bool = False, e: Optional["Endianness"] = None) -> bytes:
"""Pack one qword respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.pack(f"{endian}Q", x) if not s else struct.pack(f"{endian:s}q", x)
def u8(x: bytes, s: bool = False, e: Optional["Endianness"] = None) -> int:
"""Unpack one byte respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.unpack(f"{endian}B", x)[0] if not s else struct.unpack(f"{endian:s}b", x)[0]
def u16(x: bytes, s: bool = False, e: Optional["Endianness"] = None) -> int:
"""Unpack one word respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.unpack(f"{endian}H", x)[0] if not s else struct.unpack(f"{endian:s}h", x)[0]
def u32(x: bytes, s: bool = False, e: Optional["Endianness"] = None) -> int:
"""Unpack one dword respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.unpack(f"{endian}I", x)[0] if not s else struct.unpack(f"{endian:s}i", x)[0]
def u64(x: bytes, s: bool = False, e: Optional["Endianness"] = None) -> int:
"""Unpack one qword respecting the current architecture endianness."""
endian = e or gef.arch.endianness
return struct.unpack(f"{endian}Q", x)[0] if not s else struct.unpack(f"{endian:s}q", x)[0]
def is_ascii_string(address: int) -> bool:
"""Helper function to determine if the buffer pointed by `address` is an ASCII string (in GDB)"""
try:
return gef.memory.read_ascii_string(address) is not None
except Exception:
return False
def is_alive() -> bool:
"""Check if GDB is running."""
try:
return gdb.selected_inferior().pid > 0
except Exception:
return False
def calling_function() -> Optional[str]:
"""Return the name of the calling function"""
try:
stack_info = traceback.extract_stack()[-3]
return stack_info.name
except:
return None
#
# Decorators
#
def only_if_gdb_running(f: Callable) -> Callable:
"""Decorator wrapper to check if GDB is running."""
@functools.wraps(f)
def wrapper(*args: Any, **kwargs: Any) -> Any:
if is_alive():
return f(*args, **kwargs)
else:
warn("No debugging session active")
return wrapper
def only_if_gdb_target_local(f: Callable) -> Callable:
"""Decorator wrapper to check if GDB is running locally (target not remote)."""
@functools.wraps(f)
def wrapper(*args: Any, **kwargs: Any) -> Any:
if not is_remote_debug():
return f(*args, **kwargs)
else:
warn("This command cannot work for remote sessions.")
return wrapper
def deprecated(solution: str = "") -> Callable:
"""Decorator to add a warning when a command is obsolete and will be removed."""
def decorator(f: Callable) -> Callable:
@functools.wraps(f)
def wrapper(*args: Any, **kwargs: Any) -> Any:
caller = inspect.stack()[1]
caller_file = pathlib.Path(caller.filename)
caller_loc = caller.lineno
msg = f"{caller_file.name}:L{caller_loc} '{f.__name__}' is deprecated and will be removed in a feature release. "
if not gef:
print(msg)
elif gef.config["gef.show_deprecation_warnings"] is True:
if solution:
msg += solution
warn(msg)
return f(*args, **kwargs)
if not wrapper.__doc__:
wrapper.__doc__ = ""
wrapper.__doc__ += f"\r\n`{f.__name__}` is **DEPRECATED** and will be removed in the future.\r\n{solution}"
return wrapper
return decorator
def experimental_feature(f: Callable) -> Callable:
"""Decorator to add a warning when a feature is experimental."""
@functools.wraps(f)
def wrapper(*args: Any, **kwargs: Any) -> Any:
warn("This feature is under development, expect bugs and unstability...")
return f(*args, **kwargs)
return wrapper
def only_if_events_supported(event_type: str) -> Callable:
"""Checks if GDB supports events without crashing."""
def wrap(f: Callable) -> Callable:
def wrapped_f(*args: Any, **kwargs: Any) -> Any:
if getattr(gdb, "events") and getattr(gdb.events, event_type):
return f(*args, **kwargs)
warn("GDB events cannot be set")
return wrapped_f
return wrap
class classproperty(property):
"""Make the attribute a `classproperty`."""
def __get__(self, cls, owner):
return classmethod(self.fget).__get__(None, owner)()
def FakeExit(*args: Any, **kwargs: Any) -> NoReturn:
raise RuntimeWarning
sys.exit = FakeExit
def parse_arguments(required_arguments: Dict[Union[str, Tuple[str, str]], Any],
optional_arguments: Dict[Union[str, Tuple[str, str]], Any]) -> Callable:
"""Argument parsing decorator."""
def int_wrapper(x: str) -> int: return int(x, 0)
def decorator(f: Callable) -> Optional[Callable]:
def wrapper(*args: Any, **kwargs: Any) -> Callable:
parser = argparse.ArgumentParser(prog=args[0]._cmdline_, add_help=True)
for argname in required_arguments:
argvalue = required_arguments[argname]
argtype = type(argvalue)
if argtype is int:
argtype = int_wrapper
argname_is_list = not isinstance(argname, str)
assert not argname_is_list and isinstance(argname, str)
if not argname_is_list and argname.startswith("-"):
# optional args
if argtype is bool:
parser.add_argument(argname, action="store_true" if argvalue else "store_false")
else:
parser.add_argument(argname, type=argtype, required=True, default=argvalue)
else:
if argtype in (list, tuple):
nargs = "*"
argtype = type(argvalue[0])
else:
nargs = "?"
# positional args
parser.add_argument(argname, type=argtype, default=argvalue, nargs=nargs)
for argname in optional_arguments:
if isinstance(argname, str) and not argname.startswith("-"):
# refuse positional arguments
continue
argvalue = optional_arguments[argname]
argtype = type(argvalue)
if isinstance(argname, str):
argname = [argname,]
if argtype is int:
argtype = int_wrapper
if argtype is bool:
parser.add_argument(*argname, action="store_true" if argvalue else "store_false")
else:
parser.add_argument(*argname, type=argtype, default=argvalue)
parsed_args = parser.parse_args(*(args[1:]))
kwargs["arguments"] = parsed_args
return f(*args, **kwargs)
return wrapper
return decorator
class Color:
"""Used to colorify terminal output."""
colors = {
"normal" : "\033[0m",
"gray" : "\033[1;38;5;240m",
"light_gray" : "\033[0;37m",
"red" : "\033[31m",
"green" : "\033[32m",
"yellow" : "\033[33m",
"blue" : "\033[34m",
"pink" : "\033[35m",
"cyan" : "\033[36m",
"bold" : "\033[1m",
"underline" : "\033[4m",
"underline_off" : "\033[24m",
"highlight" : "\033[3m",
"highlight_off" : "\033[23m",
"blink" : "\033[5m",
"blink_off" : "\033[25m",
}
@staticmethod
def redify(msg: str) -> str: return Color.colorify(msg, "red")
@staticmethod
def greenify(msg: str) -> str: return Color.colorify(msg, "green")
@staticmethod
def blueify(msg: str) -> str: return Color.colorify(msg, "blue")
@staticmethod
def yellowify(msg: str) -> str: return Color.colorify(msg, "yellow")
@staticmethod
def grayify(msg: str) -> str: return Color.colorify(msg, "gray")
@staticmethod
def light_grayify(msg: str) -> str: return Color.colorify(msg, "light_gray")
@staticmethod
def pinkify(msg: str) -> str: return Color.colorify(msg, "pink")
@staticmethod
def cyanify(msg: str) -> str: return Color.colorify(msg, "cyan")
@staticmethod
def boldify(msg: str) -> str: return Color.colorify(msg, "bold")
@staticmethod
def underlinify(msg: str) -> str: return Color.colorify(msg, "underline")
@staticmethod
def highlightify(msg: str) -> str: return Color.colorify(msg, "highlight")
@staticmethod
def blinkify(msg: str) -> str: return Color.colorify(msg, "blink")
@staticmethod
def colorify(text: str, attrs: str) -> str:
"""Color text according to the given attributes."""
if gef.config["gef.disable_color"] is True: return text
colors = Color.colors
msg = [colors[attr] for attr in attrs.split() if attr in colors]
msg.append(str(text))
if colors["highlight"] in msg: msg.append(colors["highlight_off"])
if colors["underline"] in msg: msg.append(colors["underline_off"])
if colors["blink"] in msg: msg.append(colors["blink_off"])
msg.append(colors["normal"])
return "".join(msg)
class Address:
"""GEF representation of memory addresses."""
def __init__(self, **kwargs: Any) -> None:
self.value: int = kwargs.get("value", 0)
self.section: "Section" = kwargs.get("section", None)
self.info: "Zone" = kwargs.get("info", None)
return
def __str__(self) -> str:
value = format_address(self.value)
code_color = gef.config["theme.address_code"]
stack_color = gef.config["theme.address_stack"]
heap_color = gef.config["theme.address_heap"]
if self.is_in_text_segment():
return Color.colorify(value, code_color)
if self.is_in_heap_segment():
return Color.colorify(value, heap_color)
if self.is_in_stack_segment():
return Color.colorify(value, stack_color)
return value
def __int__(self) -> int:
return self.value
def is_in_text_segment(self) -> bool:
return (hasattr(self.info, "name") and ".text" in self.info.name) or \
(hasattr(self.section, "path") and get_filepath() == self.section.path and self.section.is_executable())
def is_in_stack_segment(self) -> bool:
return hasattr(self.section, "path") and "[stack]" == self.section.path
def is_in_heap_segment(self) -> bool:
return hasattr(self.section, "path") and "[heap]" == self.section.path
def dereference(self) -> Optional[int]:
addr = align_address(int(self.value))
derefed = dereference(addr)
return None if derefed is None else int(derefed)
@property
def valid(self) -> bool:
return any(map(lambda x: x.page_start <= self.value < x.page_end, gef.memory.maps))
class Permission(enum.Flag):
"""GEF representation of Linux permission."""
NONE = 0
EXECUTE = 1
WRITE = 2
READ = 4
ALL = 7
def __str__(self) -> str:
perm_str = ""
perm_str += "r" if self & Permission.READ else "-"
perm_str += "w" if self & Permission.WRITE else "-"
perm_str += "x" if self & Permission.EXECUTE else "-"
return perm_str
@classmethod
def from_info_sections(cls, *args: str) -> "Permission":
perm = cls(0)
for arg in args:
if "READONLY" in arg: perm |= Permission.READ
if "DATA" in arg: perm |= Permission.WRITE
if "CODE" in arg: perm |= Permission.EXECUTE
return perm
@classmethod
def from_process_maps(cls, perm_str: str) -> "Permission":
perm = cls(0)
if perm_str[0] == "r": perm |= Permission.READ
if perm_str[1] == "w": perm |= Permission.WRITE
if perm_str[2] == "x": perm |= Permission.EXECUTE
return perm
@classmethod
def from_info_mem(cls, perm_str: str) -> "Permission":
perm = cls(0)
# perm_str[0] shows if this is a user page, which
# we don't track
if perm_str[1] == "r": perm |= Permission.READ
if perm_str[2] == "w": perm |= Permission.WRITE
return perm
class Section:
"""GEF representation of process memory sections."""
def __init__(self, **kwargs: Any) -> None:
self.page_start: int = kwargs.get("page_start", 0)
self.page_end: int = kwargs.get("page_end", 0)
self.offset: int = kwargs.get("offset", 0)
self.permission: Permission = kwargs.get("permission", Permission(0))
self.inode: int = kwargs.get("inode", 0)
self.path: str = kwargs.get("path", "")
return
def is_readable(self) -> bool:
return (self.permission & Permission.READ) != 0
def is_writable(self) -> bool:
return (self.permission & Permission.WRITE) != 0
def is_executable(self) -> bool:
return (self.permission & Permission.EXECUTE) != 0
@property
def size(self) -> int:
if self.page_end is None or self.page_start is None:
return -1
return self.page_end - self.page_start
@property
def realpath(self) -> str:
# when in a `gef-remote` session, realpath returns the path to the binary on the local disk, not remote
return self.path if gef.session.remote is None else f"/tmp/gef/{gef.session.remote:d}/{self.path}"
def __str__(self) -> str:
return (f"Section(page_start={self.page_start:#x}, page_end={self.page_end:#x}, "
f"permissions={self.permission!s})")
Zone = collections.namedtuple("Zone", ["name", "zone_start", "zone_end", "filename"])
class Endianness(enum.Enum):
LITTLE_ENDIAN = 1
BIG_ENDIAN = 2
def __str__(self) -> str:
return "<" if self == Endianness.LITTLE_ENDIAN else ">"
def __repr__(self) -> str:
return self.name
def __int__(self) -> int:
return self.value
class FileFormatSection:
misc: Any
class FileFormat:
name: str
path: pathlib.Path
entry_point: int
checksec: Dict[str, bool]
sections: List[FileFormatSection]
def __init__(self, path: Union[str, pathlib.Path]) -> None:
raise NotImplemented
def __init_subclass__(cls: Type["FileFormat"], **kwargs):
global __registered_file_formats__
super().__init_subclass__(**kwargs)
required_attributes = ("name", "entry_point", "is_valid", "checksec",)
for attr in required_attributes:
if not hasattr(cls, attr):
raise NotImplementedError(f"File format '{cls.__name__}' is invalid: missing attribute '{attr}'")
__registered_file_formats__.add(cls)
return
@classmethod
def is_valid(cls, path: pathlib.Path) -> bool:
raise NotImplemented
def __str__(self) -> str:
return f"{self.name}('{self.path.absolute()}', entry @ {self.entry_point:#x})"
class Elf(FileFormat):
"""Basic ELF parsing.
Ref:
- http://www.skyfree.org/linux/references/ELF_Format.pdf
- https://refspecs.linuxfoundation.org/elf/elfspec_ppc.pdf
- https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html
"""
class Class(enum.Enum):
ELF_32_BITS = 0x01
ELF_64_BITS = 0x02
ELF_MAGIC = 0x7f454c46
class Abi(enum.Enum):
X86_64 = 0x3e
X86_32 = 0x03
ARM = 0x28
MIPS = 0x08
POWERPC = 0x14
POWERPC64 = 0x15
SPARC = 0x02
SPARC64 = 0x2b
AARCH64 = 0xb7
RISCV = 0xf3
IA64 = 0x32
M68K = 0x04
class Type(enum.Enum):
ET_RELOC = 1
ET_EXEC = 2
ET_DYN = 3
ET_CORE = 4
class OsAbi(enum.Enum):
SYSTEMV = 0x00
HPUX = 0x01
NETBSD = 0x02
LINUX = 0x03
SOLARIS = 0x06
AIX = 0x07
IRIX = 0x08
FREEBSD = 0x09
OPENBSD = 0x0C
e_magic: int = ELF_MAGIC
e_class: "Elf.Class" = Class.ELF_32_BITS
e_endianness: Endianness = Endianness.LITTLE_ENDIAN
e_eiversion: int
e_osabi: "Elf.OsAbi"
e_abiversion: int
e_pad: bytes
e_type: "Elf.Type" = Type.ET_EXEC
e_machine: Abi = Abi.X86_32
e_version: int
e_entry: int
e_phoff: int
e_shoff: int
e_flags: int
e_ehsize: int
e_phentsize: int
e_phnum: int
e_shentsize: int
e_shnum: int
e_shstrndx: int
path: pathlib.Path
phdrs : List["Phdr"]
shdrs : List["Shdr"]
name: str = "ELF"
__checksec : Dict[str, bool]
def __init__(self, path: Union[str, pathlib.Path]) -> None:
"""Instantiate an ELF object. A valid ELF must be provided, or an exception will be thrown."""
if isinstance(path, str):
self.path = pathlib.Path(path).expanduser()
elif isinstance(path, pathlib.Path):
self.path = path
else:
raise TypeError
if not self.path.exists():
raise FileNotFoundError(f"'{self.path}' not found/readable, most gef features will not work")
self.__checksec = {}
with self.path.open("rb") as self.fd:
# off 0x0
self.e_magic, e_class, e_endianness, self.e_eiversion = self.read_and_unpack(">IBBB")
if self.e_magic != Elf.ELF_MAGIC:
# The ELF is corrupted, GDB won't handle it, no point going further
raise RuntimeError("Not a valid ELF file (magic)")
self.e_class, self.e_endianness = Elf.Class(e_class), Endianness(e_endianness)
if self.e_endianness != gef.arch.endianness:
warn("Unexpected endianness for architecture")
endian = self.e_endianness
# off 0x7
e_osabi, self.e_abiversion = self.read_and_unpack(f"{endian}BB")
self.e_osabi = Elf.OsAbi(e_osabi)
# off 0x9
self.e_pad = self.read(7)
# off 0x10
e_type, e_machine, self.e_version = self.read_and_unpack(f"{endian}HHI")
self.e_type, self.e_machine = Elf.Type(e_type), Elf.Abi(e_machine)
# off 0x18
if self.e_class == Elf.Class.ELF_64_BITS:
self.e_entry, self.e_phoff, self.e_shoff = self.read_and_unpack(f"{endian}QQQ")
else:
self.e_entry, self.e_phoff, self.e_shoff = self.read_and_unpack(f"{endian}III")
self.e_flags, self.e_ehsize, self.e_phentsize, self.e_phnum = self.read_and_unpack(f"{endian}IHHH")
self.e_shentsize, self.e_shnum, self.e_shstrndx = self.read_and_unpack(f"{endian}HHH")
self.phdrs = []
for i in range(self.e_phnum):
self.phdrs.append(Phdr(self, self.e_phoff + self.e_phentsize * i))
self.shdrs = []
for i in range(self.e_shnum):
self.shdrs.append(Shdr(self, self.e_shoff + self.e_shentsize * i))
return
def read(self, size: int) -> bytes:
return self.fd.read(size)
def read_and_unpack(self, fmt: str) -> Tuple[Any, ...]:
size = struct.calcsize(fmt)
data = self.fd.read(size)
return struct.unpack(fmt, data)
def seek(self, off: int) -> None:
self.fd.seek(off, 0)
def __str__(self) -> str:
return f"ELF('{self.path.absolute()}', {self.e_class.name}, {self.e_machine.name})"
def __repr__(self) -> str:
return f"ELF('{self.path.absolute()}', {self.e_class.name}, {self.e_machine.name})"
@property
def entry_point(self) -> int:
return self.e_entry
@classmethod
def is_valid(cls, path: pathlib.Path) -> bool:
return u32(path.open("rb").read(4), e = Endianness.BIG_ENDIAN) == Elf.ELF_MAGIC
@property
def checksec(self) -> Dict[str, bool]:
"""Check the security property of the ELF binary. The following properties are:
- Canary
- NX
- PIE
- Fortify
- Partial/Full RelRO.
Return a dict() with the different keys mentioned above, and the boolean
associated whether the protection was found."""
if not self.__checksec:
def __check_security_property(opt: str, filename: str, pattern: str) -> bool:
cmd = [readelf,]
cmd += opt.split()
cmd += [filename,]
lines = gef_execute_external(cmd, as_list=True)
for line in lines:
if re.search(pattern, line):
return True
return False
abspath = str(self.path.absolute())
readelf = gef.session.constants["readelf"]
self.__checksec["Canary"] = __check_security_property("-rs", abspath, r"__stack_chk_fail") is True
has_gnu_stack = __check_security_property("-W -l", abspath, r"GNU_STACK") is True
if has_gnu_stack:
self.__checksec["NX"] = __check_security_property("-W -l", abspath, r"GNU_STACK.*RWE") is False
else:
self.__checksec["NX"] = False
self.__checksec["PIE"] = __check_security_property("-h", abspath, r":.*EXEC") is False
self.__checksec["Fortify"] = __check_security_property("-s", abspath, r"_chk@GLIBC") is True
self.__checksec["Partial RelRO"] = __check_security_property("-l", abspath, r"GNU_RELRO") is True
self.__checksec["Full RelRO"] = self.__checksec["Partial RelRO"] and __check_security_property("-d", abspath, r"BIND_NOW") is True
return self.__checksec
@classproperty
@deprecated("use `Elf.Abi.X86_64`")
def X86_64(cls) -> int: return Elf.Abi.X86_64.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.X86_32`")
def X86_32(cls) -> int : return Elf.Abi.X86_32.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.ARM`")
def ARM(cls) -> int : return Elf.Abi.ARM.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.MIPS`")
def MIPS(cls) -> int : return Elf.Abi.MIPS.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.POWERPC`")
def POWERPC(cls) -> int : return Elf.Abi.POWERPC.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.POWERPC64`")
def POWERPC64(cls) -> int : return Elf.Abi.POWERPC64.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.SPARC`")
def SPARC(cls) -> int : return Elf.Abi.SPARC.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.SPARC64`")
def SPARC64(cls) -> int : return Elf.Abi.SPARC64.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.AARCH64`")
def AARCH64(cls) -> int : return Elf.Abi.AARCH64.value # pylint: disable=no-self-argument
@classproperty
@deprecated("use `Elf.Abi.RISCV`")
def RISCV(cls) -> int : return Elf.Abi.RISCV.value # pylint: disable=no-self-argument
class Phdr:
class Type(enum.IntEnum):
PT_NULL = 0
PT_LOAD = 1
PT_DYNAMIC = 2
PT_INTERP = 3
PT_NOTE = 4
PT_SHLIB = 5
PT_PHDR = 6
PT_TLS = 7
PT_LOOS = 0x60000000
PT_GNU_EH_FRAME = 0x6474e550
PT_GNU_STACK = 0x6474e551
PT_GNU_RELRO = 0x6474e552
PT_GNU_PROPERTY = 0x6474e553
PT_LOSUNW = 0x6ffffffa
PT_SUNWBSS = 0x6ffffffa
PT_SUNWSTACK = 0x6ffffffb
PT_HISUNW = PT_HIOS = 0x6fffffff
PT_LOPROC = 0x70000000
PT_ARM_EIDX = 0x70000001
PT_MIPS_ABIFLAGS= 0x70000003
PT_HIPROC = 0x7fffffff
UNKNOWN_PHDR = 0xffffffff
@classmethod
def _missing_(cls, _:int) -> Type:
return cls.UNKNOWN_PHDR
class Flags(enum.IntFlag):
PF_X = 1
PF_W = 2
PF_R = 4
p_type: "Phdr.Type"
p_flags: "Phdr.Flags"
p_offset: int
p_vaddr: int
p_paddr: int
p_filesz: int
p_memsz: int
p_align: int
def __init__(self, elf: Elf, off: int) -> None:
if not elf:
return
elf.seek(off)
self.offset = off
endian = elf.e_endianness
if elf.e_class == Elf.Class.ELF_64_BITS:
p_type, p_flags, self.p_offset = elf.read_and_unpack(f"{endian}IIQ")
self.p_vaddr, self.p_paddr = elf.read_and_unpack(f"{endian}QQ")
self.p_filesz, self.p_memsz, self.p_align = elf.read_and_unpack(f"{endian}QQQ")
else:
p_type, self.p_offset = elf.read_and_unpack(f"{endian}II")
self.p_vaddr, self.p_paddr = elf.read_and_unpack(f"{endian}II")
self.p_filesz, self.p_memsz, p_flags, self.p_align = elf.read_and_unpack(f"{endian}IIII")
self.p_type, self.p_flags = Phdr.Type(p_type), Phdr.Flags(p_flags)
return
def __str__(self) -> str:
return (f"Phdr(offset={self.offset}, type={self.p_type.name}, flags={self.p_flags.name}, "
f"vaddr={self.p_vaddr}, paddr={self.p_paddr}, filesz={self.p_filesz}, "
f"memsz={self.p_memsz}, align={self.p_align})")
class Shdr:
class Type(enum.IntEnum):
SHT_NULL = 0
SHT_PROGBITS = 1
SHT_SYMTAB = 2
SHT_STRTAB = 3
SHT_RELA = 4
SHT_HASH = 5
SHT_DYNAMIC = 6
SHT_NOTE = 7
SHT_NOBITS = 8
SHT_REL = 9
SHT_SHLIB = 10
SHT_DYNSYM = 11
SHT_NUM = 12
SHT_INIT_ARRAY = 14
SHT_FINI_ARRAY = 15
SHT_PREINIT_ARRAY = 16
SHT_GROUP = 17
SHT_SYMTAB_SHNDX = 18
SHT_LOOS = 0x60000000
SHT_GNU_ATTRIBUTES = 0x6ffffff5
SHT_GNU_HASH = 0x6ffffff6
SHT_GNU_LIBLIST = 0x6ffffff7
SHT_CHECKSUM = 0x6ffffff8
SHT_LOSUNW = 0x6ffffffa
SHT_SUNW_move = 0x6ffffffa
SHT_SUNW_COMDAT = 0x6ffffffb
SHT_SUNW_syminfo = 0x6ffffffc
SHT_GNU_verdef = 0x6ffffffd
SHT_GNU_verneed = 0x6ffffffe
SHT_GNU_versym = 0x6fffffff
SHT_LOPROC = 0x70000000
SHT_ARM_EXIDX = 0x70000001
SHT_X86_64_UNWIND = 0x70000001
SHT_ARM_ATTRIBUTES = 0x70000003
SHT_MIPS_OPTIONS = 0x7000000d
DT_MIPS_INTERFACE = 0x7000002a
SHT_HIPROC = 0x7fffffff
SHT_LOUSER = 0x80000000
SHT_HIUSER = 0x8fffffff
UNKNOWN_SHDR = 0xffffffff
@classmethod
def _missing_(cls, _:int) -> Type:
return cls.UNKNOWN_SHDR
class Flags(enum.IntFlag):
WRITE = 1
ALLOC = 2
EXECINSTR = 4
MERGE = 0x10
STRINGS = 0x20
INFO_LINK = 0x40
LINK_ORDER = 0x80
OS_NONCONFORMING = 0x100
GROUP = 0x200
TLS = 0x400
COMPRESSED = 0x800
RELA_LIVEPATCH = 0x00100000
RO_AFTER_INIT = 0x00200000
ORDERED = 0x40000000
EXCLUDE = 0x80000000
UNKNOWN_FLAG = 0xffffffff
@classmethod
def _missing_(cls, _:int):
return cls.UNKNOWN_FLAG
sh_name: int
sh_type: "Shdr.Type"
sh_flags: "Shdr.Flags"
sh_addr: int
sh_offset: int
sh_size: int
sh_link: int
sh_info: int
sh_addralign: int
sh_entsize: int
name: str
def __init__(self, elf: Optional[Elf], off: int) -> None:
if elf is None:
return
elf.seek(off)
endian = elf.e_endianness
if elf.e_class == Elf.Class.ELF_64_BITS:
self.sh_name, sh_type, sh_flags = elf.read_and_unpack(f"{endian}IIQ")
self.sh_addr, self.sh_offset = elf.read_and_unpack(f"{endian}QQ")
self.sh_size, self.sh_link, self.sh_info = elf.read_and_unpack(f"{endian}QII")
self.sh_addralign, self.sh_entsize = elf.read_and_unpack(f"{endian}QQ")
else:
self.sh_name, sh_type, sh_flags = elf.read_and_unpack(f"{endian}III")
self.sh_addr, self.sh_offset = elf.read_and_unpack(f"{endian}II")
self.sh_size, self.sh_link, self.sh_info = elf.read_and_unpack(f"{endian}III")
self.sh_addralign, self.sh_entsize = elf.read_and_unpack(f"{endian}II")
self.sh_type = Shdr.Type(sh_type)
self.sh_flags = Shdr.Flags(sh_flags)
stroff = elf.e_shoff + elf.e_shentsize * elf.e_shstrndx
if elf.e_class == Elf.Class.ELF_64_BITS:
elf.seek(stroff + 16 + 8)
offset = u64(elf.read(8))
else:
elf.seek(stroff + 12 + 4)
offset = u32(elf.read(4))
elf.seek(offset + self.sh_name)
self.name = ""
while True:
c = u8(elf.read(1))
if c == 0:
break
self.name += chr(c)
return
def __str__(self) -> str:
return (f"Shdr(name={self.name}, type={self.sh_type.name}, flags={self.sh_flags.name}, "
f"addr={self.sh_addr:#x}, offset={self.sh_offset}, size={self.sh_size}, link={self.sh_link}, "
f"info={self.sh_info}, addralign={self.sh_addralign}, entsize={self.sh_entsize})")
class Instruction:
"""GEF representation of a CPU instruction."""
def __init__(self, address: int, location: str, mnemo: str, operands: List[str], opcodes: bytes) -> None:
self.address, self.location, self.mnemonic, self.operands, self.opcodes = \
address, location, mnemo, operands, opcodes
return
# Allow formatting an instruction with {:o} to show opcodes.
# The number of bytes to display can be configured, e.g. {:4o} to only show 4 bytes of the opcodes
def __format__(self, format_spec: str) -> str:
if len(format_spec) == 0 or format_spec[-1] != "o":
return str(self)
if format_spec == "o":
opcodes_len = len(self.opcodes)
else:
opcodes_len = int(format_spec[:-1])
opcodes_text = "".join(f"{b:02x}" for b in self.opcodes[:opcodes_len])
if opcodes_len < len(self.opcodes):
opcodes_text += "..."
return (f"{self.address:#10x} {opcodes_text:{opcodes_len * 2 + 3:d}s} {self.location:16} "
f"{self.mnemonic:6} {', '.join(self.operands)}")
def __str__(self) -> str:
return f"{self.address:#10x} {self.location:16} {self.mnemonic:6} {', '.join(self.operands)}"
def is_valid(self) -> bool:
return "(bad)" not in self.mnemonic
def size(self) -> int:
return len(self.opcodes)
@deprecated("Use GefHeapManager.find_main_arena_addr()")
def search_for_main_arena() -> int:
return GefHeapManager.find_main_arena_addr()
class GlibcHeapInfo:
"""Glibc heap_info struct"""
@staticmethod
def heap_info_t() -> Type[ctypes.Structure]:
class heap_info_cls(ctypes.Structure):
pass
pointer = ctypes.c_uint64 if gef.arch.ptrsize == 8 else ctypes.c_uint32
pad_size = -5 * gef.arch.ptrsize & (gef.heap.malloc_alignment - 1)
fields = [
("ar_ptr", ctypes.POINTER(GlibcArena.malloc_state_t())),
("prev", ctypes.POINTER(heap_info_cls)),
("size", pointer)
]
if gef.libc.version >= (2, 5):
fields += [
("mprotect_size", pointer)
]
pad_size = -6 * gef.arch.ptrsize & (gef.heap.malloc_alignment - 1)
if gef.libc.version >= (2, 34):
fields += [
("pagesize", pointer)
]
pad_size = -3 * gef.arch.ptrsize & (gef.heap.malloc_alignment - 1)
fields += [
("pad", ctypes.c_uint8*pad_size)
]
heap_info_cls._fields_ = fields
return heap_info_cls
def __init__(self, addr: Union[str, int]) -> None:
self.__address : int = parse_address(f"&{addr}") if isinstance(addr, str) else addr
self.reset()
return
def reset(self):
self._sizeof = ctypes.sizeof(GlibcHeapInfo.heap_info_t())
self._data = gef.memory.read(self.__address, ctypes.sizeof(GlibcHeapInfo.heap_info_t()))
self._heap_info = GlibcHeapInfo.heap_info_t().from_buffer_copy(self._data)
return
def __getattr__(self, item: Any) -> Any:
if item in dir(self._heap_info):
return ctypes.cast(getattr(self._heap_info, item), ctypes.c_void_p).value
return getattr(self, item)
def __abs__(self) -> int:
return self.__address
def __int__(self) -> int:
return self.__address
@property
def address(self) -> int:
return self.__address
@property
def sizeof(self) -> int:
return self._sizeof
@property
def addr(self) -> int:
return int(self)
@property
def heap_start(self) -> int:
# check special case: first heap of non-main-arena
if self.ar_ptr - self.address < 0x60:
# the first heap of a non-main-arena starts with a `heap_info`
# struct, which should fit easily into 0x60 bytes throughout
# all architectures and glibc versions. If this check succeeds
# then we are currently looking at such a "first heap"
arena = GlibcArena(f"*{self.ar_ptr:#x}")
heap_addr = arena.heap_addr()
if heap_addr:
return heap_addr
else:
err(f"Cannot find heap address for arena {self.ar_ptr:#x}")
return 0
return self.address + self.sizeof
@property
def heap_end(self) -> int:
return self.address + self.size
class GlibcArena:
"""Glibc arena class"""
NFASTBINS = 10
NBINS = 128
NSMALLBINS = 64
BINMAPSHIFT = 5
BITSPERMAP = 1 << BINMAPSHIFT
BINMAPSIZE = NBINS // BITSPERMAP
@staticmethod
def malloc_state_t() -> Type[ctypes.Structure]:
pointer = ctypes.c_uint64 if gef and gef.arch.ptrsize == 8 else ctypes.c_uint32
fields = [
("mutex", ctypes.c_uint32),
("flags", ctypes.c_uint32),
]
if gef and gef.libc.version and gef.libc.version >= (2, 27):
# https://elixir.bootlin.com/glibc/glibc-2.27/source/malloc/malloc.c#L1684
fields += [
("have_fastchunks", ctypes.c_uint32),
("UNUSED_c", ctypes.c_uint32), # padding to align to 0x10
]
fields += [
("fastbinsY", GlibcArena.NFASTBINS * pointer),
("top", pointer),
("last_remainder", pointer),
("bins", (GlibcArena.NBINS * 2 - 2) * pointer),
("binmap", GlibcArena.BINMAPSIZE * ctypes.c_uint32),
("next", pointer),
("next_free", pointer)
]
if gef and gef.libc.version and gef.libc.version >= (2, 23):
# https://elixir.bootlin.com/glibc/glibc-2.23/source/malloc/malloc.c#L1719
fields += [
("attached_threads", pointer)
]
fields += [
("system_mem", pointer),
("max_system_mem", pointer),
]
class malloc_state_cls(ctypes.Structure):
_fields_ = fields
return malloc_state_cls
def __init__(self, addr: str) -> None:
try:
self.__address : int = parse_address(f"&{addr}")
except gdb.error:
self.__address : int = GefHeapManager.find_main_arena_addr()
# if `find_main_arena_addr` throws `gdb.error` on symbol lookup:
# it means the session is not started, so just propagate the exception
self.reset()
return
def reset(self):
self._sizeof = ctypes.sizeof(GlibcArena.malloc_state_t())
self._data = gef.memory.read(self.__address, ctypes.sizeof(GlibcArena.malloc_state_t()))
self.__arena = GlibcArena.malloc_state_t().from_buffer_copy(self._data)
return
def __abs__(self) -> int:
return self.__address
def __int__(self) -> int:
return self.__address
def __iter__(self) -> Generator["GlibcArena", None, None]:
main_arena = int(gef.heap.main_arena)
current_arena = self
yield current_arena
while True:
if current_arena.next == 0 or current_arena.next == main_arena:
break
current_arena = GlibcArena(f"*{current_arena.next:#x} ")
yield current_arena
return
def __eq__(self, other: "GlibcArena") -> bool:
return self.__address == int(other)
def __str__(self) -> str:
properties = f"base={self.__address:#x}, top={self.top:#x}, " \
f"last_remainder={self.last_remainder:#x}, next={self.next:#x}"
return (f"{Color.colorify('Arena', 'blue bold underline')}({properties})")
def __repr__(self) -> str:
return f"GlibcArena(address={self.__address:#x}, size={self._sizeof})"
@property
def address(self) -> int:
return self.__address
@property
def sizeof(self) -> int:
return self._sizeof
@property
def addr(self) -> int:
return int(self)
@property
def top(self) -> int:
return self.__arena.top
@property
def last_remainder(self) -> int:
return self.__arena.last_remainder
@property
def fastbinsY(self) -> ctypes.Array:
return self.__arena.fastbinsY
@property
def bins(self) -> ctypes.Array:
return self.__arena.bins
@property
def binmap(self) -> ctypes.Array:
return self.__arena.binmap
@property
def next(self) -> int:
return self.__arena.next
@property
def next_free(self) -> int:
return self.__arena.next_free
@property
def attached_threads(self) -> int:
return self.__arena.attached_threads
@property
def system_mem(self) -> int:
return self.__arena.system_mem
@property
def max_system_mem(self) -> int:
return self.__arena.max_system_mem
def fastbin(self, i: int) -> Optional["GlibcFastChunk"]:
"""Return head chunk in fastbinsY[i]."""
addr = int(self.fastbinsY[i])
if addr == 0:
return None
return GlibcFastChunk(addr + 2 * gef.arch.ptrsize)
def bin(self, i: int) -> Tuple[int, int]:
idx = i * 2
fd = int(self.bins[idx])
bk = int(self.bins[idx + 1])
return fd, bk
def bin_at(self, i) -> int:
header_sz = 2 * gef.arch.ptrsize
offset = ctypes.addressof(self.__arena.bins) - ctypes.addressof(self.__arena)
return self.__address + offset + (i-1) * 2 * gef.arch.ptrsize + header_sz
def is_main_arena(self) -> bool:
return gef.heap.main_arena is not None and int(self) == int(gef.heap.main_arena)
def heap_addr(self, allow_unaligned: bool = False) -> Optional[int]:
if self.is_main_arena():
heap_section = gef.heap.base_address
if not heap_section:
return None
return heap_section
_addr = int(self) + self.sizeof
if allow_unaligned:
return _addr
return gef.heap.malloc_align_address(_addr)
def get_heap_info_list(self) -> Optional[List[GlibcHeapInfo]]:
if self.is_main_arena():
return None
heap_addr = self.get_heap_for_ptr(self.top)
heap_infos = [GlibcHeapInfo(heap_addr)]
while heap_infos[-1].prev is not None:
prev = int(heap_infos[-1].prev)
heap_info = GlibcHeapInfo(prev)
heap_infos.append(heap_info)
return heap_infos[::-1]
@staticmethod
def get_heap_for_ptr(ptr: int) -> int:
"""Find the corresponding heap for a given pointer (int).
See https://github.com/bminor/glibc/blob/glibc-2.34/malloc/arena.c#L129"""
if is_32bit():
default_mmap_threshold_max = 512 * 1024
else: # 64bit
default_mmap_threshold_max = 4 * 1024 * 1024 * cached_lookup_type("long").sizeof
heap_max_size = 2 * default_mmap_threshold_max
return ptr & ~(heap_max_size - 1)
@staticmethod
def verify(addr: int) -> bool:
"""Verify that the address matches a possible valid GlibcArena"""
try:
test_arena = GlibcArena(f"*{addr:#x}")
cur_arena = GlibcArena(f"*{test_arena.next:#x}")
while cur_arena != test_arena:
if cur_arena == 0:
return False
cur_arena = GlibcArena(f"*{cur_arena.next:#x}")
except Exception as e:
return False
return True
class GlibcChunk:
"""Glibc chunk class. The default behavior (from_base=False) is to interpret the data starting at the memory
address pointed to as the chunk data. Setting from_base to True instead treats that data as the chunk header.
Ref: https://sploitfun.wordpress.com/2015/02/10/understanding-glibc-malloc/."""
class ChunkFlags(enum.IntFlag):
PREV_INUSE = 1
IS_MMAPPED = 2
NON_MAIN_ARENA = 4
def __str__(self) -> str:
return f" | ".join([
Color.greenify("PREV_INUSE") if self.value & self.PREV_INUSE else Color.redify("PREV_INUSE"),
Color.greenify("IS_MMAPPED") if self.value & self.IS_MMAPPED else Color.redify("IS_MMAPPED"),
Color.greenify("NON_MAIN_ARENA") if self.value & self.NON_MAIN_ARENA else Color.redify("NON_MAIN_ARENA")
])
@staticmethod
def malloc_chunk_t() -> Type[ctypes.Structure]:
pointer = ctypes.c_uint64 if gef and gef.arch.ptrsize == 8 else ctypes.c_uint32
class malloc_chunk_cls(ctypes.Structure):
pass
malloc_chunk_cls._fields_ = [
("prev_size", pointer),
("size", pointer),
("fd", pointer),
("bk", pointer),
("fd_nextsize", ctypes.POINTER(malloc_chunk_cls)),
("bk_nextsize", ctypes.POINTER(malloc_chunk_cls)),
]
return malloc_chunk_cls
def __init__(self, addr: int, from_base: bool = False, allow_unaligned: bool = True) -> None:
ptrsize = gef.arch.ptrsize
self.data_address = addr + 2 * ptrsize if from_base else addr
self.base_address = addr if from_base else addr - 2 * ptrsize
if not allow_unaligned:
self.data_address = gef.heap.malloc_align_address(self.data_address)
self.size_addr = int(self.data_address - ptrsize)
self.prev_size_addr = self.base_address
self.reset()
return
def reset(self):
self._sizeof = ctypes.sizeof(GlibcChunk.malloc_chunk_t())
self._data = gef.memory.read(
self.base_address, ctypes.sizeof(GlibcChunk.malloc_chunk_t()))
self._chunk = GlibcChunk.malloc_chunk_t().from_buffer_copy(self._data)
return
@property
def prev_size(self) -> int:
return self._chunk.prev_size
@property
def size(self) -> int:
return self._chunk.size & (~0x07)
@property
def flags(self) -> ChunkFlags:
return GlibcChunk.ChunkFlags(self._chunk.size & 0x07)
@property
def fd(self) -> int:
return self._chunk.fd
@property
def bk(self) -> int:
return self._chunk.bk
@property
def fd_nextsize(self) -> int:
return self._chunk.fd_nextsize
@property
def bk_nextsize(self) -> int:
return self._chunk.bk_nextsize
def get_usable_size(self) -> int:
# https://github.com/sploitfun/lsploits/blob/master/glibc/malloc/malloc.c#L4537
ptrsz = gef.arch.ptrsize
cursz = self.size
if cursz == 0: return cursz
if self.has_m_bit(): return cursz - 2 * ptrsz
return cursz - ptrsz
@property
def usable_size(self) -> int:
return self.get_usable_size()
def get_prev_chunk_size(self) -> int:
return gef.memory.read_integer(self.prev_size_addr)
def __iter__(self) -> Generator["GlibcChunk", None, None]:
current_chunk = self
top = gef.heap.main_arena.top
while True:
yield current_chunk
if current_chunk.base_address == top:
break
if current_chunk.size == 0:
break
next_chunk_addr = current_chunk.get_next_chunk_addr()
if not Address(value=next_chunk_addr).valid:
break
next_chunk = current_chunk.get_next_chunk()
if next_chunk is None:
break
current_chunk = next_chunk
return
def get_next_chunk(self, allow_unaligned: bool = False) -> "GlibcChunk":
addr = self.get_next_chunk_addr()
return GlibcChunk(addr, allow_unaligned=allow_unaligned)
def get_next_chunk_addr(self) -> int:
return self.data_address + self.size
def has_p_bit(self) -> bool:
return bool(self.flags & GlibcChunk.ChunkFlags.PREV_INUSE)
def has_m_bit(self) -> bool:
return bool(self.flags & GlibcChunk.ChunkFlags.IS_MMAPPED)
def has_n_bit(self) -> bool:
return bool(self.flags & GlibcChunk.ChunkFlags.NON_MAIN_ARENA)
def is_used(self) -> bool:
"""Check if the current block is used by:
- checking the M bit is true
- or checking that next chunk PREV_INUSE flag is true"""
if self.has_m_bit():
return True
next_chunk = self.get_next_chunk()
return True if next_chunk.has_p_bit() else False
def __str_sizes(self) -> str:
msg = []
failed = False
try:
msg.append("Chunk size: {0:d} ({0:#x})".format(self.size))
msg.append("Usable size: {0:d} ({0:#x})".format(self.usable_size))
failed = True
except gdb.MemoryError:
msg.append(f"Chunk size: Cannot read at {self.size_addr:#x} (corrupted?)")
try:
msg.append("Previous chunk size: {0:d} ({0:#x})".format(self.get_prev_chunk_size()))
failed = True
except gdb.MemoryError:
msg.append(f"Previous chunk size: Cannot read at {self.base_address:#x} (corrupted?)")
if failed:
msg.append(str(self.flags))
return "\n".join(msg)
def _str_pointers(self) -> str:
fwd = self.data_address
bkw = self.data_address + gef.arch.ptrsize
msg = []
try:
msg.append(f"Forward pointer: {self.fd:#x}")
except gdb.MemoryError:
msg.append(f"Forward pointer: {fwd:#x} (corrupted?)")
try:
msg.append(f"Backward pointer: {self.bk:#x}")
except gdb.MemoryError:
msg.append(f"Backward pointer: {bkw:#x} (corrupted?)")
return "\n".join(msg)
def __str__(self) -> str:
return (f"{Color.colorify('Chunk', 'yellow bold underline')}(addr={self.data_address:#x}, "
f"size={self.size:#x}, flags={self.flags!s})")
def psprint(self) -> str:
msg = [
str(self),
self.__str_sizes(),
]
if not self.is_used():
msg.append(f"\n\n{self._str_pointers()}")
return "\n".join(msg) + "\n"
class GlibcFastChunk(GlibcChunk):
@property
def fd(self) -> int:
assert(gef and gef.libc.version)
if gef.libc.version < (2, 32):
return self._chunk.fd
return self.reveal_ptr(self.data_address)
def protect_ptr(self, pos: int, pointer: int) -> int:
"""https://elixir.bootlin.com/glibc/glibc-2.32/source/malloc/malloc.c#L339"""
assert(gef and gef.libc.version)
if gef.libc.version < (2, 32):
return pointer
return (pos >> 12) ^ pointer
def reveal_ptr(self, pointer: int) -> int:
"""https://elixir.bootlin.com/glibc/glibc-2.32/source/malloc/malloc.c#L341"""
assert(gef and gef.libc.version)
if gef.libc.version < (2, 32):
return pointer
return gef.memory.read_integer(pointer) ^ (pointer >> 12)
class GlibcTcacheChunk(GlibcFastChunk):
pass
@deprecated("Use GefLibcManager.find_libc_version()")
def get_libc_version() -> Tuple[int, ...]:
return GefLibcManager.find_libc_version()
def titlify(text: str, color: Optional[str] = None, msg_color: Optional[str] = None) -> str:
"""Print a centered title."""
_, cols = get_terminal_size()
nb = (cols - len(text) - 2) // 2
line_color = color or gef.config["theme.default_title_line"]
text_color = msg_color or gef.config["theme.default_title_message"]
msg = [Color.colorify(f"{HORIZONTAL_LINE * nb} ", line_color),
Color.colorify(text, text_color),
Color.colorify(f" {HORIZONTAL_LINE * nb}", line_color)]
return "".join(msg)
def dbg(msg: str) -> None:
if gef.config["gef.debug"] is True:
gef_print(f"{Color.colorify('[=]', 'bold cyan')} {msg}")
return
def err(msg: str) -> None:
gef_print(f"{Color.colorify('[!]', 'bold red')} {msg}")
return
def warn(msg: str) -> None:
gef_print(f"{Color.colorify('[*]', 'bold yellow')} {msg}")
return
def ok(msg: str) -> None:
gef_print(f"{Color.colorify('[+]', 'bold green')} {msg}")
return
def info(msg: str) -> None:
gef_print(f"{Color.colorify('[+]', 'bold blue')} {msg}")
return
def push_context_message(level: str, message: str) -> None:
"""Push the message to be displayed the next time the context is invoked."""
if level not in ("error", "warn", "ok", "info"):
err(f"Invalid level '{level}', discarding message")
return
gef.ui.context_messages.append((level, message))
return
def show_last_exception() -> None:
"""Display the last Python exception."""
def _show_code_line(fname: str, idx: int) -> str:
fname = os.path.expanduser(os.path.expandvars(fname))
with open(fname, "r") as f:
_data = f.readlines()
return _data[idx - 1] if 0 < idx < len(_data) else ""
gef_print("")
exc_type, exc_value, exc_traceback = sys.exc_info()
gef_print(" Exception raised ".center(80, HORIZONTAL_LINE))
gef_print(f"{Color.colorify(exc_type.__name__, 'bold underline red')}: {exc_value}")
gef_print(" Detailed stacktrace ".center(80, HORIZONTAL_LINE))
for fs in traceback.extract_tb(exc_traceback)[::-1]:
filename, lineno, method, code = fs
if not code or not code.strip():
code = _show_code_line(filename, lineno)
gef_print(f"""{DOWN_ARROW} File "{Color.yellowify(filename)}", line {lineno:d}, in {Color.greenify(method)}()""")
gef_print(f" {RIGHT_ARROW} {code}")
gef_print(" Version ".center(80, HORIZONTAL_LINE))
gdb.execute("version full")
gef_print(" Last 10 GDB commands ".center(80, HORIZONTAL_LINE))
gdb.execute("show commands")
gef_print(" Runtime environment ".center(80, HORIZONTAL_LINE))
gef_print(f"* GDB: {gdb.VERSION}")
gef_print(f"* Python: {sys.version_info.major:d}.{sys.version_info.minor:d}.{sys.version_info.micro:d} - {sys.version_info.releaselevel}")
gef_print(f"* OS: {platform.system()} - {platform.release()} ({platform.machine()})")
try:
lsb_release = which("lsb_release")
gdb.execute(f"!{lsb_release} -a")
except FileNotFoundError:
gef_print("lsb_release is missing, cannot collect additional debug information")
gef_print(HORIZONTAL_LINE*80)
gef_print("")
return
def gef_pystring(x: bytes) -> str:
"""Returns a sanitized version as string of the bytes list given in input."""
res = str(x, encoding="utf-8")
substs = [("\n", "\\n"), ("\r", "\\r"), ("\t", "\\t"), ("\v", "\\v"), ("\b", "\\b"), ]
for x, y in substs: res = res.replace(x, y)
return res
def gef_pybytes(x: str) -> bytes:
"""Returns an immutable bytes list from the string given as input."""
return bytes(str(x), encoding="utf-8")
@lru_cache()
def which(program: str) -> pathlib.Path:
"""Locate a command on the filesystem."""
for path in os.environ["PATH"].split(os.pathsep):
dirname = pathlib.Path(path)
fpath = dirname / program
if os.access(fpath, os.X_OK):
return fpath
raise FileNotFoundError(f"Missing file `{program}`")
def style_byte(b: int, color: bool = True) -> str:
style = {
"nonprintable": "yellow",
"printable": "white",
"00": "gray",
"0a": "blue",
"ff": "green",
}
sbyte = f"{b:02x}"
if not color or gef.config["highlight.regex"]:
return sbyte
if sbyte in style:
st = style[sbyte]
elif chr(b) in (string.ascii_letters + string.digits + string.punctuation + " "):
st = style.get("printable")
else:
st = style.get("nonprintable")
if st:
sbyte = Color.colorify(sbyte, st)
return sbyte
def hexdump(source: ByteString, length: int = 0x10, separator: str = ".", show_raw: bool = False, show_symbol: bool = True, base: int = 0x00) -> str:
"""Return the hexdump of `src` argument.
@param source *MUST* be of type bytes or bytearray
@param length is the length of items per line
@param separator is the default character to use if one byte is not printable
@param show_raw if True, do not add the line nor the text translation
@param base is the start address of the block being hexdump
@return a string with the hexdump"""
result = []
align = gef.arch.ptrsize * 2 + 2 if is_alive() else 18
for i in range(0, len(source), length):
chunk = bytearray(source[i : i + length])
hexa = " ".join([style_byte(b, color=not show_raw) for b in chunk])
if show_raw:
result.append(hexa)
continue
text = "".join([chr(b) if 0x20 <= b < 0x7F else separator for b in chunk])
if show_symbol:
sym = gdb_get_location_from_symbol(base + i)
sym = "<{:s}+{:04x}>".format(*sym) if sym else ""
else:
sym = ""
result.append(f"{base + i:#0{align}x} {sym} {hexa:<{3 * length}} {text}")
return "\n".join(result)
def is_debug() -> bool:
"""Check if debug mode is enabled."""
return gef.config["gef.debug"] is True
def buffer_output() -> bool:
"""Check if output should be buffered until command completion."""
return gef.config["gef.buffer"] is True
def hide_context() -> bool:
"""Helper function to hide the context pane."""
gef.ui.context_hidden = True
return True
def unhide_context() -> bool:
"""Helper function to unhide the context pane."""
gef.ui.context_hidden = False
return True
class DisableContextOutputContext:
def __enter__(self) -> None:
hide_context()
return
def __exit__(self, *exc: Any) -> None:
unhide_context()
return
class RedirectOutputContext:
def __init__(self, to: str = "/dev/null") -> None:
self.redirection_target_file = to
return
def __enter__(self) -> None:
"""Redirect all GDB output to `to_file` parameter. By default, `to_file` redirects to `/dev/null`."""
gdb.execute("set logging overwrite")
gdb.execute(f"set logging file {self.redirection_target_file}")
gdb.execute("set logging redirect on")
gdb.execute("set logging on")
return
def __exit__(self, *exc: Any) -> None:
"""Disable the output redirection, if any."""
gdb.execute("set logging off")
gdb.execute("set logging redirect off")
return
def enable_redirect_output(to_file: str = "/dev/null") -> None:
"""Redirect all GDB output to `to_file` parameter. By default, `to_file` redirects to `/dev/null`."""
gdb.execute("set logging overwrite")
gdb.execute(f"set logging file {to_file}")
gdb.execute("set logging redirect on")
gdb.execute("set logging on")
return
def disable_redirect_output() -> None:
"""Disable the output redirection, if any."""
gdb.execute("set logging off")
gdb.execute("set logging redirect off")
return
def gef_makedirs(path: str, mode: int = 0o755) -> pathlib.Path:
"""Recursive mkdir() creation. If successful, return the absolute path of the directory created."""
fpath = pathlib.Path(path)
if not fpath.is_dir():
fpath.mkdir(mode=mode, exist_ok=True, parents=True)
return fpath.absolute()
@lru_cache()
def gdb_lookup_symbol(sym: str) -> Optional[Tuple[Optional[str], Optional[Tuple[gdb.Symtab_and_line, ...]]]]:
"""Fetch the proper symbol or None if not defined."""
try:
return gdb.decode_line(sym)[1]
except gdb.error:
return None
@lru_cache(maxsize=512)
def gdb_get_location_from_symbol(address: int) -> Optional[Tuple[str, int]]:
"""Retrieve the location of the `address` argument from the symbol table.
Return a tuple with the name and offset if found, None otherwise."""
# this is horrible, ugly hack and shitty perf...
# find a *clean* way to get gdb.Location from an address
sym = str(gdb.execute(f"info symbol {address:#x}", to_string=True))
if sym.startswith("No symbol matches"):
return None
i = sym.find(" in section ")
sym = sym[:i].split()
name, offset = sym[0], 0
if len(sym) == 3 and sym[2].isdigit():
offset = int(sym[2])
return name, offset
def gdb_disassemble(start_pc: int, **kwargs: int) -> Generator[Instruction, None, None]:
"""Disassemble instructions from `start_pc` (Integer). Accepts the following named
parameters:
- `end_pc` (Integer) only instructions whose start address fall in the interval from
start_pc to end_pc are returned.
- `count` (Integer) list at most this many disassembled instructions
If `end_pc` and `count` are not provided, the function will behave as if `count=1`.
Return an iterator of Instruction objects
"""
frame = gdb.selected_frame()
arch = frame.architecture()
for insn in arch.disassemble(start_pc, **kwargs):
address = insn["addr"]
asm = insn["asm"].rstrip().split(None, 1)
if len(asm) > 1:
mnemo, operands = asm
operands = operands.split(",")
else:
mnemo, operands = asm[0], []
loc = gdb_get_location_from_symbol(address)
location = "<{}+{}>".format(*loc) if loc else ""
opcodes = gef.memory.read(insn["addr"], insn["length"])
yield Instruction(address, location, mnemo, operands, opcodes)
def gdb_get_nth_previous_instruction_address(addr: int, n: int) -> Optional[int]:
"""Return the address (Integer) of the `n`-th instruction before `addr`."""
# fixed-length ABI
if gef.arch.instruction_length:
return max(0, addr - n * gef.arch.instruction_length)
# variable-length ABI
cur_insn_addr = gef_current_instruction(addr).address
# we try to find a good set of previous instructions by "guessing" disassembling backwards
# the 15 comes from the longest instruction valid size
for i in range(15 * n, 0, -1):
try:
insns = list(gdb_disassemble(addr - i, end_pc=cur_insn_addr))
except gdb.MemoryError:
# this is because we can hit an unmapped page trying to read backward
break
# 1. check that the disassembled instructions list size can satisfy
if len(insns) < n + 1: # we expect the current instruction plus the n before it
continue
# If the list of instructions is longer than what we need, then we
# could get lucky and already have more than what we need, so slice down
insns = insns[-n - 1 :]
# 2. check that the sequence ends with the current address
if insns[-1].address != cur_insn_addr:
continue
# 3. check all instructions are valid
if all(insn.is_valid() for insn in insns):
return insns[0].address
return None
def gdb_get_nth_next_instruction_address(addr: int, n: int) -> int:
"""Return the address (Integer) of the `n`-th instruction after `addr`."""
# fixed-length ABI
if gef.arch.instruction_length:
return addr + n * gef.arch.instruction_length
# variable-length ABI
insn = list(gdb_disassemble(addr, count=n))[-1]
return insn.address
def gef_instruction_n(addr: int, n: int) -> Instruction:
"""Return the `n`-th instruction after `addr` as an Instruction object."""
return list(gdb_disassemble(addr, count=n + 1))[n]
def gef_get_instruction_at(addr: int) -> Instruction:
"""Return the full Instruction found at the specified address."""
insn = next(gef_disassemble(addr, 1))
return insn
def gef_current_instruction(addr: int) -> Instruction:
"""Return the current instruction as an Instruction object."""
return gef_instruction_n(addr, 0)
def gef_next_instruction(addr: int) -> Instruction:
"""Return the next instruction as an Instruction object."""
return gef_instruction_n(addr, 1)
def gef_disassemble(addr: int, nb_insn: int, nb_prev: int = 0) -> Generator[Instruction, None, None]:
"""Disassemble `nb_insn` instructions after `addr` and `nb_prev` before `addr`.
Return an iterator of Instruction objects."""
nb_insn = max(1, nb_insn)
if nb_prev:
try:
start_addr = gdb_get_nth_previous_instruction_address(addr, nb_prev)
if start_addr:
for insn in gdb_disassemble(start_addr, count=nb_prev):
if insn.address == addr: break
yield insn
except gdb.MemoryError:
# If the address pointing to the previous instruction(s) is not mapped, simply skip them
pass
for insn in gdb_disassemble(addr, count=nb_insn):
yield insn
def gef_execute_external(command: Sequence[str], as_list: bool = False, **kwargs: Any) -> Union[str, List[str]]:
"""Execute an external command and return the result."""
res = subprocess.check_output(command, stderr=subprocess.STDOUT, shell=kwargs.get("shell", False))
return [gef_pystring(_) for _ in res.splitlines()] if as_list else gef_pystring(res)
def gef_execute_gdb_script(commands: str) -> None:
"""Execute the parameter `source` as GDB command. This is done by writing `commands` to
a temporary file, which is then executed via GDB `source` command. The tempfile is then deleted."""
fd, fname = tempfile.mkstemp(suffix=".gdb", prefix="gef_")
with os.fdopen(fd, "w") as f:
f.write(commands)
f.flush()
fname = pathlib.Path(fname)
if fname.is_file() and os.access(fname, os.R_OK):
gdb.execute(f"source {fname}")
fname.unlink()
return
@deprecated("Use Elf(fname).checksec()")
def checksec(filename: str) -> Dict[str, bool]:
return Elf(filename).checksec
@lru_cache()
def get_arch() -> str:
"""Return the binary's architecture."""
if is_alive():
arch = gdb.selected_frame().architecture()
return arch.name()
arch_str = gdb.execute("show architecture", to_string=True).strip()
pat = "The target architecture is set automatically (currently "
if arch_str.startswith(pat):
arch_str = arch_str[len(pat):].rstrip(")")
return arch_str
pat = "The target architecture is assumed to be "
if arch_str.startswith(pat):
return arch_str[len(pat):]
pat = "The target architecture is set to "
if arch_str.startswith(pat):
# GDB version >= 10.1
if '"auto"' in arch_str:
return re.findall(r"currently \"(.+)\"", arch_str)[0]
return re.findall(r"\"(.+)\"", arch_str)[0]
# Unknown, we throw an exception to be safe
raise RuntimeError(f"Unknown architecture: {arch_str}")
@deprecated("Use `gef.binary.entry_point` instead")
def get_entry_point() -> Optional[int]:
"""Return the binary entry point."""
return gef.binary.entry_point if gef.binary else None
def is_pie(fpath: str) -> bool:
return Elf(fpath).checksec["PIE"]
@deprecated("Prefer `gef.arch.endianness == Endianness.BIG_ENDIAN`")
def is_big_endian() -> bool:
return gef.arch.endianness == Endianness.BIG_ENDIAN
@deprecated("gef.arch.endianness == Endianness.LITTLE_ENDIAN")
def is_little_endian() -> bool:
return gef.arch.endianness == Endianness.LITTLE_ENDIAN
def flags_to_human(reg_value: int, value_table: Dict[int, str]) -> str:
"""Return a human readable string showing the flag states."""
flags = []
for bit_index, name in value_table.items():
flags.append(Color.boldify(name.upper()) if reg_value & (1<<bit_index) != 0 else name.lower())
return f"[{' '.join(flags)}]"
@lru_cache()
def get_section_base_address(name: str) -> Optional[int]:
section = process_lookup_path(name)
return section.page_start if section else None
@lru_cache()
def get_zone_base_address(name: str) -> Optional[int]:
zone = file_lookup_name_path(name, get_filepath())
return zone.zone_start if zone else None
#
# Architecture classes
#
@deprecated("Using the decorator `register_architecture` is unecessary")
def register_architecture(cls: Type["Architecture"]) -> Type["Architecture"]:
return cls
class ArchitectureBase:
"""Class decorator for declaring an architecture to GEF."""
aliases: Union[Tuple[()], Tuple[Union[str, Elf.Abi], ...]] = ()
def __init_subclass__(cls: Type["ArchitectureBase"], **kwargs):
global __registered_architectures__
super().__init_subclass__(**kwargs)
for key in getattr(cls, "aliases"):
if issubclass(cls, Architecture):
__registered_architectures__[key] = cls
return
class Architecture(ArchitectureBase):
"""Generic metaclass for the architecture supported by GEF."""
# Mandatory defined attributes by inheriting classes
arch: str
mode: str
all_registers: Union[Tuple[()], Tuple[str, ...]]
nop_insn: bytes
return_register: str
flag_register: Optional[str]
instruction_length: Optional[int]
flags_table: Dict[int, str]
syscall_register: Optional[str]
syscall_instructions: Union[Tuple[()], Tuple[str, ...]]
function_parameters: Union[Tuple[()], Tuple[str, ...]]
# Optionally defined attributes
_ptrsize: Optional[int] = None
_endianness: Optional[Endianness] = None
special_registers: Union[Tuple[()], Tuple[str, ...]] = ()
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
attributes = ("arch", "mode", "aliases", "all_registers", "nop_insn",
"return_register", "flag_register", "instruction_length", "flags_table",
"function_parameters",)
if not all(map(lambda x: hasattr(cls, x), attributes)):
raise NotImplementedError
def __str__(self) -> str:
return f"Architecture({self.arch}, {self.mode or 'None'}, {repr(self.endianness)})"
@staticmethod
def supports_gdb_arch(gdb_arch: str) -> Optional[bool]:
"""If implemented by a child `Architecture`, this function dictates if the current class
supports the loaded ELF file (which can be accessed via `gef.binary`). This callback
function will override any assumption made by GEF to determine the architecture."""
return None
def flag_register_to_human(self, val: Optional[int] = None) -> str:
raise NotImplementedError
def is_call(self, insn: Instruction) -> bool:
raise NotImplementedError
def is_ret(self, insn: Instruction) -> bool:
raise NotImplementedError
def is_conditional_branch(self, insn: Instruction) -> bool:
raise NotImplementedError
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
raise NotImplementedError
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
raise NotImplementedError
def canary_address(self) -> int:
raise NotImplementedError
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
raise NotImplementedError
def reset_caches(self) -> None:
self.__get_register_for_selected_frame.cache_clear()
return
def __get_register(self, regname: str) -> int:
"""Return a register's value."""
curframe = gdb.selected_frame()
key = curframe.pc() ^ int(curframe.read_register('sp')) # todo: check when/if gdb.Frame implements `level()`
return self.__get_register_for_selected_frame(regname, key)
@lru_cache()
def __get_register_for_selected_frame(self, regname: str, hash_key: int) -> int:
# 1st chance
try:
return parse_address(regname)
except gdb.error:
pass
# 2nd chance - if an exception, propagate it
regname = regname.lstrip("$")
value = gdb.selected_frame().read_register(regname)
return int(value)
def register(self, name: str) -> int:
if not is_alive():
raise gdb.error("No debugging session active")
return self.__get_register(name)
@property
def registers(self) -> Generator[str, None, None]:
yield from self.all_registers
@property
def pc(self) -> int:
return self.register("$pc")
@property
def sp(self) -> int:
return self.register("$sp")
@property
def fp(self) -> int:
return self.register("$fp")
@property
def ptrsize(self) -> int:
if not self._ptrsize:
res = cached_lookup_type("size_t")
if res is not None:
self._ptrsize = res.sizeof
else:
self._ptrsize = gdb.parse_and_eval("$pc").type.sizeof
return self._ptrsize
@property
def endianness(self) -> Endianness:
if not self._endianness:
output = gdb.execute("show endian", to_string=True).strip().lower()
if "little endian" in output:
self._endianness = Endianness.LITTLE_ENDIAN
elif "big endian" in output:
self._endianness = Endianness.BIG_ENDIAN
else:
raise OSError(f"No valid endianess found in '{output}'")
return self._endianness
def get_ith_parameter(self, i: int, in_func: bool = True) -> Tuple[str, Optional[int]]:
"""Retrieves the correct parameter used for the current function call."""
reg = self.function_parameters[i]
val = self.register(reg)
key = reg
return key, val
class GenericArchitecture(Architecture):
arch = "Generic"
mode = ""
aliases = ("GenericArchitecture",)
all_registers = ()
instruction_length = 0
return_register = ""
function_parameters = ()
syscall_register = ""
syscall_instructions = ()
nop_insn = b""
flag_register = None
flags_table = {}
class RISCV(Architecture):
arch = "RISCV"
mode = "RISCV"
aliases = ("RISCV", Elf.Abi.RISCV)
all_registers = ("$zero", "$ra", "$sp", "$gp", "$tp", "$t0", "$t1",
"$t2", "$fp", "$s1", "$a0", "$a1", "$a2", "$a3",
"$a4", "$a5", "$a6", "$a7", "$s2", "$s3", "$s4",
"$s5", "$s6", "$s7", "$s8", "$s9", "$s10", "$s11",
"$t3", "$t4", "$t5", "$t6",)
return_register = "$a0"
function_parameters = ("$a0", "$a1", "$a2", "$a3", "$a4", "$a5", "$a6", "$a7")
syscall_register = "$a7"
syscall_instructions = ("ecall",)
nop_insn = b"\x00\x00\x00\x13"
# RISC-V has no flags registers
flag_register = None
flags_table = {}
@property
def instruction_length(self) -> int:
return 4
def is_call(self, insn: Instruction) -> bool:
return insn.mnemonic == "call"
def is_ret(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
if mnemo == "ret":
return True
elif (mnemo == "jalr" and insn.operands[0] == "zero" and
insn.operands[1] == "ra" and insn.operands[2] == 0):
return True
elif (mnemo == "c.jalr" and insn.operands[0] == "ra"):
return True
return False
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
raise OSError(f"Architecture {cls.arch} not supported yet")
@property
def ptrsize(self) -> int:
if self._ptrsize is not None:
return self._ptrsize
if is_alive():
self._ptrsize = gdb.parse_and_eval("$pc").type.sizeof
return self._ptrsize
return 4
def is_conditional_branch(self, insn: Instruction) -> bool:
return insn.mnemonic.startswith("b")
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
def long_to_twos_complement(v: int) -> int:
"""Convert a python long value to its two's complement."""
if is_32bit():
if v & 0x80000000:
return v - 0x100000000
elif is_64bit():
if v & 0x8000000000000000:
return v - 0x10000000000000000
else:
raise OSError("RISC-V: ELF file is not ELF32 or ELF64. This is not currently supported")
return v
mnemo = insn.mnemonic
condition = mnemo[1:]
if condition.endswith("z"):
# r2 is the zero register if we are comparing to 0
rs1 = gef.arch.register(insn.operands[0])
rs2 = gef.arch.register("$zero")
condition = condition[:-1]
elif len(insn.operands) > 2:
# r2 is populated with the second operand
rs1 = gef.arch.register(insn.operands[0])
rs2 = gef.arch.register(insn.operands[1])
else:
raise OSError(f"RISC-V: Failed to get rs1 and rs2 for instruction: `{insn}`")
# If the conditional operation is not unsigned, convert the python long into
# its two's complement
if not condition.endswith("u"):
rs2 = long_to_twos_complement(rs2)
rs1 = long_to_twos_complement(rs1)
else:
condition = condition[:-1]
if condition == "eq":
if rs1 == rs2: taken, reason = True, f"{rs1}={rs2}"
else: taken, reason = False, f"{rs1}!={rs2}"
elif condition == "ne":
if rs1 != rs2: taken, reason = True, f"{rs1}!={rs2}"
else: taken, reason = False, f"{rs1}={rs2}"
elif condition == "lt":
if rs1 < rs2: taken, reason = True, f"{rs1}<{rs2}"
else: taken, reason = False, f"{rs1}>={rs2}"
elif condition == "le":
if rs1 <= rs2: taken, reason = True, f"{rs1}<={rs2}"
else: taken, reason = False, f"{rs1}>{rs2}"
elif condition == "ge":
if rs1 < rs2: taken, reason = True, f"{rs1}>={rs2}"
else: taken, reason = False, f"{rs1}<{rs2}"
else:
raise OSError(f"RISC-V: Conditional instruction `{insn}` not supported yet")
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
ra = None
if self.is_ret(insn):
ra = gef.arch.register("$ra")
elif frame.older():
ra = frame.older().pc()
return ra
class ARM(Architecture):
aliases = ("ARM", Elf.Abi.ARM)
arch = "ARM"
all_registers = ("$r0", "$r1", "$r2", "$r3", "$r4", "$r5", "$r6",
"$r7", "$r8", "$r9", "$r10", "$r11", "$r12", "$sp",
"$lr", "$pc", "$cpsr",)
# https://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0041c/Caccegih.html
nop_insn = b"\x01\x10\xa0\xe1" # mov r1, r1
return_register = "$r0"
flag_register: str = "$cpsr"
flags_table = {
31: "negative",
30: "zero",
29: "carry",
28: "overflow",
7: "interrupt",
6: "fast",
5: "thumb",
}
function_parameters = ("$r0", "$r1", "$r2", "$r3")
syscall_register = "$r7"
syscall_instructions = ("swi 0x0", "swi NR")
_endianness = Endianness.LITTLE_ENDIAN
def is_thumb(self) -> bool:
"""Determine if the machine is currently in THUMB mode."""
return is_alive() and (self.cpsr & (1 << 5) == 1)
@property
def pc(self) -> Optional[int]:
pc = gef.arch.register("$pc")
if self.is_thumb():
pc += 1
return pc
@property
def cpsr(self) -> int:
if not is_alive():
raise RuntimeError("Cannot get CPSR, program not started?")
return gef.arch.register(self.flag_register)
@property
def mode(self) -> str:
return "THUMB" if self.is_thumb() else "ARM"
@property
def instruction_length(self) -> Optional[int]:
# Thumb instructions have variable-length (2 or 4-byte)
return None if self.is_thumb() else 4
@property
def ptrsize(self) -> int:
return 4
def is_call(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
call_mnemos = {"bl", "blx"}
return mnemo in call_mnemos
def is_ret(self, insn: Instruction) -> bool:
pop_mnemos = {"pop"}
branch_mnemos = {"bl", "bx"}
write_mnemos = {"ldr", "add"}
if insn.mnemonic in pop_mnemos:
return insn.operands[-1] == " pc}"
if insn.mnemonic in branch_mnemos:
return insn.operands[-1] == "lr"
if insn.mnemonic in write_mnemos:
return insn.operands[0] == "pc"
return False
def flag_register_to_human(self, val: Optional[int] = None) -> str:
# https://www.botskool.com/user-pages/tutorials/electronics/arm-7-tutorial-part-1
if val is None:
reg = self.flag_register
val = gef.arch.register(reg)
return flags_to_human(val, self.flags_table)
def is_conditional_branch(self, insn: Instruction) -> bool:
conditions = {"eq", "ne", "lt", "le", "gt", "ge", "vs", "vc", "mi", "pl", "hi", "ls", "cc", "cs"}
return insn.mnemonic[-2:] in conditions
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo = insn.mnemonic
# ref: https://www.davespace.co.uk/arm/introduction-to-arm/conditional.html
flags = dict((self.flags_table[k], k) for k in self.flags_table)
val = gef.arch.register(self.flag_register)
taken, reason = False, ""
if mnemo.endswith("eq"): taken, reason = bool(val&(1<<flags["zero"])), "Z"
elif mnemo.endswith("ne"): taken, reason = not bool(val&(1<<flags["zero"])), "!Z"
elif mnemo.endswith("lt"):
taken, reason = bool(val&(1<<flags["negative"])) != bool(val&(1<<flags["overflow"])), "N!=V"
elif mnemo.endswith("le"):
taken, reason = bool(val&(1<<flags["zero"])) or \
bool(val&(1<<flags["negative"])) != bool(val&(1<<flags["overflow"])), "Z || N!=V"
elif mnemo.endswith("gt"):
taken, reason = bool(val&(1<<flags["zero"])) == 0 and \
bool(val&(1<<flags["negative"])) == bool(val&(1<<flags["overflow"])), "!Z && N==V"
elif mnemo.endswith("ge"):
taken, reason = bool(val&(1<<flags["negative"])) == bool(val&(1<<flags["overflow"])), "N==V"
elif mnemo.endswith("vs"): taken, reason = bool(val&(1<<flags["overflow"])), "V"
elif mnemo.endswith("vc"): taken, reason = not val&(1<<flags["overflow"]), "!V"
elif mnemo.endswith("mi"):
taken, reason = bool(val&(1<<flags["negative"])), "N"
elif mnemo.endswith("pl"):
taken, reason = not val&(1<<flags["negative"]), "N==0"
elif mnemo.endswith("hi"):
taken, reason = bool(val&(1<<flags["carry"])) and not bool(val&(1<<flags["zero"])), "C && !Z"
elif mnemo.endswith("ls"):
taken, reason = not val&(1<<flags["carry"]) or bool(val&(1<<flags["zero"])), "!C || Z"
elif mnemo.endswith("cs"): taken, reason = bool(val&(1<<flags["carry"])), "C"
elif mnemo.endswith("cc"): taken, reason = not val&(1<<flags["carry"]), "!C"
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> int:
ra = None
if self.is_ret(insn):
# If it's a pop, we have to peek into the stack, otherwise use lr
if insn.mnemonic == "pop":
ra_addr = gef.arch.sp + (len(insn.operands)-1) * self.ptrsize
ra = to_unsigned_long(dereference(ra_addr))
elif insn.mnemonic == "ldr":
return to_unsigned_long(dereference(gef.arch.sp))
else: # 'bx lr' or 'add pc, lr, #0'
return gef.arch.register("$lr")
elif frame.older():
ra = frame.older().pc()
return ra
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
_NR_mprotect = 125
insns = [
"push {r0-r2, r7}",
f"mov r1, {addr & 0xffff:d}",
f"mov r0, {(addr & 0xffff0000) >> 16:d}",
"lsl r0, r0, 16",
"add r0, r0, r1",
f"mov r1, {size & 0xffff:d}",
f"mov r2, {perm.value & 0xff:d}",
f"mov r7, {_NR_mprotect:d}",
"svc 0",
"pop {r0-r2, r7}",
]
return "; ".join(insns)
class AARCH64(ARM):
aliases = ("ARM64", "AARCH64", Elf.Abi.AARCH64)
arch = "ARM64"
mode: str = ""
all_registers = (
"$x0", "$x1", "$x2", "$x3", "$x4", "$x5", "$x6", "$x7",
"$x8", "$x9", "$x10", "$x11", "$x12", "$x13", "$x14","$x15",
"$x16", "$x17", "$x18", "$x19", "$x20", "$x21", "$x22", "$x23",
"$x24", "$x25", "$x26", "$x27", "$x28", "$x29", "$x30", "$sp",
"$pc", "$cpsr", "$fpsr", "$fpcr",)
return_register = "$x0"
flag_register = "$cpsr"
flags_table = {
31: "negative",
30: "zero",
29: "carry",
28: "overflow",
7: "interrupt",
9: "endian",
6: "fast",
5: "t32",
4: "m[4]",
}
function_parameters = ("$x0", "$x1", "$x2", "$x3", "$x4", "$x5", "$x6", "$x7",)
syscall_register = "$x8"
syscall_instructions = ("svc $x0",)
def is_call(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
call_mnemos = {"bl", "blr"}
return mnemo in call_mnemos
def flag_register_to_human(self, val: Optional[int] = None) -> str:
# https://events.linuxfoundation.org/sites/events/files/slides/KoreaLinuxForum-2014.pdf
reg = self.flag_register
if not val:
val = gef.arch.register(reg)
return flags_to_human(val, self.flags_table)
def is_aarch32(self) -> bool:
"""Determine if the CPU is currently in AARCH32 mode from runtime."""
return (self.cpsr & (1 << 4) != 0) and (self.cpsr & (1 << 5) == 0)
def is_thumb32(self) -> bool:
"""Determine if the CPU is currently in THUMB32 mode from runtime."""
return (self.cpsr & (1 << 4) == 1) and (self.cpsr & (1 << 5) == 1)
@property
def ptrsize(self) -> int:
"""Determine the size of pointer from the current CPU mode"""
if not is_alive():
return 8
if self.is_aarch32():
return 4
if self.is_thumb32():
return 2
return 8
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
_NR_mprotect = 226
insns = [
"str x8, [sp, -16]!",
"str x0, [sp, -16]!",
"str x1, [sp, -16]!",
"str x2, [sp, -16]!",
f"mov x8, {_NR_mprotect:d}",
f"movz x0, {addr & 0xFFFF:#x}",
f"movk x0, {(addr >> 16) & 0xFFFF:#x}, lsl 16",
f"movk x0, {(addr >> 32) & 0xFFFF:#x}, lsl 32",
f"movk x0, {(addr >> 48) & 0xFFFF:#x}, lsl 48",
f"movz x1, {size & 0xFFFF:#x}",
f"movk x1, {(size >> 16) & 0xFFFF:#x}, lsl 16",
f"mov x2, {perm.value:d}",
"svc 0",
"ldr x2, [sp], 16",
"ldr x1, [sp], 16",
"ldr x0, [sp], 16",
"ldr x8, [sp], 16",
]
return "; ".join(insns)
def is_conditional_branch(self, insn: Instruction) -> bool:
# https://www.element14.com/community/servlet/JiveServlet/previewBody/41836-102-1-229511/ARM.Reference_Manual.pdf
# sect. 5.1.1
mnemo = insn.mnemonic
branch_mnemos = {"cbnz", "cbz", "tbnz", "tbz"}
return mnemo.startswith("b.") or mnemo in branch_mnemos
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo, operands = insn.mnemonic, insn.operands
taken, reason = False, ""
if mnemo in {"cbnz", "cbz", "tbnz", "tbz"}:
reg = f"${operands[0]}"
op = gef.arch.register(reg)
if mnemo == "cbnz":
if op!=0: taken, reason = True, f"{reg}!=0"
else: taken, reason = False, f"{reg}==0"
elif mnemo == "cbz":
if op == 0: taken, reason = True, f"{reg}==0"
else: taken, reason = False, f"{reg}!=0"
elif mnemo == "tbnz":
# operands[1] has one or more white spaces in front, then a #, then the number
# so we need to eliminate them
i = int(operands[1].strip().lstrip("#"))
if (op & 1<<i) != 0: taken, reason = True, f"{reg}&1<<{i}!=0"
else: taken, reason = False, f"{reg}&1<<{i}==0"
elif mnemo == "tbz":
# operands[1] has one or more white spaces in front, then a #, then the number
# so we need to eliminate them
i = int(operands[1].strip().lstrip("#"))
if (op & 1<<i) == 0: taken, reason = True, f"{reg}&1<<{i}==0"
else: taken, reason = False, f"{reg}&1<<{i}!=0"
if not reason:
taken, reason = super().is_branch_taken(insn)
return taken, reason
class X86(Architecture):
aliases: Tuple[Union[str, Elf.Abi], ...] = ("X86", Elf.Abi.X86_32)
arch = "X86"
mode = "32"
nop_insn = b"\x90"
flag_register: str = "$eflags"
special_registers = ("$cs", "$ss", "$ds", "$es", "$fs", "$gs", )
gpr_registers = ("$eax", "$ebx", "$ecx", "$edx", "$esp", "$ebp", "$esi", "$edi", "$eip", )
all_registers = gpr_registers + ( flag_register,) + special_registers
instruction_length = None
return_register = "$eax"
function_parameters = ("$esp", )
flags_table = {
6: "zero",
0: "carry",
2: "parity",
4: "adjust",
7: "sign",
8: "trap",
9: "interrupt",
10: "direction",
11: "overflow",
16: "resume",
17: "virtualx86",
21: "identification",
}
syscall_register = "$eax"
syscall_instructions = ("sysenter", "int 0x80")
_ptrsize = 4
_endianness = Endianness.LITTLE_ENDIAN
def flag_register_to_human(self, val: Optional[int] = None) -> str:
reg = self.flag_register
if not val:
val = gef.arch.register(reg)
return flags_to_human(val, self.flags_table)
def is_call(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
call_mnemos = {"call", "callq"}
return mnemo in call_mnemos
def is_ret(self, insn: Instruction) -> bool:
return insn.mnemonic == "ret"
def is_conditional_branch(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
branch_mnemos = {
"ja", "jnbe", "jae", "jnb", "jnc", "jb", "jc", "jnae", "jbe", "jna",
"jcxz", "jecxz", "jrcxz", "je", "jz", "jg", "jnle", "jge", "jnl",
"jl", "jnge", "jle", "jng", "jne", "jnz", "jno", "jnp", "jpo", "jns",
"jo", "jp", "jpe", "js"
}
return mnemo in branch_mnemos
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo = insn.mnemonic
# all kudos to fG! (https://github.com/gdbinit/Gdbinit/blob/master/gdbinit#L1654)
flags = dict((self.flags_table[k], k) for k in self.flags_table)
val = gef.arch.register(self.flag_register)
taken, reason = False, ""
if mnemo in ("ja", "jnbe"):
taken, reason = not val&(1<<flags["carry"]) and not bool(val&(1<<flags["zero"])), "!C && !Z"
elif mnemo in ("jae", "jnb", "jnc"):
taken, reason = not val&(1<<flags["carry"]), "!C"
elif mnemo in ("jb", "jc", "jnae"):
taken, reason = bool(val&(1<<flags["carry"])) != 0, "C"
elif mnemo in ("jbe", "jna"):
taken, reason = bool(val&(1<<flags["carry"])) or bool(val&(1<<flags["zero"])), "C || Z"
elif mnemo in ("jcxz", "jecxz", "jrcxz"):
cx = gef.arch.register("$rcx") if is_x86_64() else gef.arch.register("$ecx")
taken, reason = cx == 0, "!$CX"
elif mnemo in ("je", "jz"):
taken, reason = bool(val&(1<<flags["zero"])), "Z"
elif mnemo in ("jne", "jnz"):
taken, reason = not bool(val&(1<<flags["zero"])), "!Z"
elif mnemo in ("jg", "jnle"):
taken, reason = not bool(val&(1<<flags["zero"])) and bool(val&(1<<flags["overflow"])) == bool(val&(1<<flags["sign"])), "!Z && S==O"
elif mnemo in ("jge", "jnl"):
taken, reason = bool(val&(1<<flags["sign"])) == bool(val&(1<<flags["overflow"])), "S==O"
elif mnemo in ("jl", "jnge"):
taken, reason = bool(val&(1<<flags["overflow"]) != val&(1<<flags["sign"])), "S!=O"
elif mnemo in ("jle", "jng"):
taken, reason = bool(val&(1<<flags["zero"])) or bool(val&(1<<flags["overflow"])) != bool(val&(1<<flags["sign"])), "Z || S!=O"
elif mnemo in ("jo",):
taken, reason = bool(val&(1<<flags["overflow"])), "O"
elif mnemo in ("jno",):
taken, reason = not val&(1<<flags["overflow"]), "!O"
elif mnemo in ("jpe", "jp"):
taken, reason = bool(val&(1<<flags["parity"])), "P"
elif mnemo in ("jnp", "jpo"):
taken, reason = not val&(1<<flags["parity"]), "!P"
elif mnemo in ("js",):
taken, reason = bool(val&(1<<flags["sign"])) != 0, "S"
elif mnemo in ("jns",):
taken, reason = not val&(1<<flags["sign"]), "!S"
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
ra = None
if self.is_ret(insn):
ra = to_unsigned_long(dereference(gef.arch.sp))
if frame.older():
ra = frame.older().pc()
return ra
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
_NR_mprotect = 125
insns = [
"pushad",
"pushfd",
f"mov eax, {_NR_mprotect:d}",
f"mov ebx, {addr:d}",
f"mov ecx, {size:d}",
f"mov edx, {perm.value:d}",
"int 0x80",
"popfd",
"popad",
]
return "; ".join(insns)
def get_ith_parameter(self, i: int, in_func: bool = True) -> Tuple[str, Optional[int]]:
if in_func:
i += 1 # Account for RA being at the top of the stack
sp = gef.arch.sp
sz = gef.arch.ptrsize
loc = sp + (i * sz)
val = gef.memory.read_integer(loc)
key = f"[sp + {i * sz:#x}]"
return key, val
class X86_64(X86):
aliases = ("X86_64", Elf.Abi.X86_64, "i386:x86-64")
arch = "X86"
mode = "64"
gpr_registers = (
"$rax", "$rbx", "$rcx", "$rdx", "$rsp", "$rbp", "$rsi", "$rdi", "$rip",
"$r8", "$r9", "$r10", "$r11", "$r12", "$r13", "$r14", "$r15", )
all_registers = gpr_registers + ( X86.flag_register, ) + X86.special_registers
return_register = "$rax"
function_parameters = ["$rdi", "$rsi", "$rdx", "$rcx", "$r8", "$r9"]
syscall_register = "$rax"
syscall_instructions = ["syscall"]
# We don't want to inherit x86's stack based param getter
get_ith_parameter = Architecture.get_ith_parameter
_ptrsize = 8
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
_NR_mprotect = 10
insns = [
"pushfq",
"push rax",
"push rdi",
"push rsi",
"push rdx",
"push rcx",
"push r11",
f"mov rax, {_NR_mprotect:d}",
f"mov rdi, {addr:d}",
f"mov rsi, {size:d}",
f"mov rdx, {perm.value:d}",
"syscall",
"pop r11",
"pop rcx",
"pop rdx",
"pop rsi",
"pop rdi",
"pop rax",
"popfq",
]
return "; ".join(insns)
def canary_address(self) -> int:
return self.register("fs_base") + 0x28
class PowerPC(Architecture):
aliases = ("PowerPC", Elf.Abi.POWERPC, "PPC")
arch = "PPC"
mode = "PPC32"
all_registers = (
"$r0", "$r1", "$r2", "$r3", "$r4", "$r5", "$r6", "$r7",
"$r8", "$r9", "$r10", "$r11", "$r12", "$r13", "$r14", "$r15",
"$r16", "$r17", "$r18", "$r19", "$r20", "$r21", "$r22", "$r23",
"$r24", "$r25", "$r26", "$r27", "$r28", "$r29", "$r30", "$r31",
"$pc", "$msr", "$cr", "$lr", "$ctr", "$xer", "$trap",)
instruction_length = 4
nop_insn = b"\x60\x00\x00\x00" # https://developer.ibm.com/articles/l-ppc/
return_register = "$r0"
flag_register: str = "$cr"
flags_table = {
3: "negative[0]",
2: "positive[0]",
1: "equal[0]",
0: "overflow[0]",
# cr7
31: "less[7]",
30: "greater[7]",
29: "equal[7]",
28: "overflow[7]",
}
function_parameters = ("$i0", "$i1", "$i2", "$i3", "$i4", "$i5")
syscall_register = "$r0"
syscall_instructions = ("sc",)
ptrsize = 4
def flag_register_to_human(self, val: Optional[int] = None) -> str:
# https://www.cebix.net/downloads/bebox/pem32b.pdf (% 2.1.3)
if not val:
reg = self.flag_register
val = gef.arch.register(reg)
return flags_to_human(val, self.flags_table)
def is_call(self, insn: Instruction) -> bool:
return False
def is_ret(self, insn: Instruction) -> bool:
return insn.mnemonic == "blr"
def is_conditional_branch(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
branch_mnemos = {"beq", "bne", "ble", "blt", "bgt", "bge"}
return mnemo in branch_mnemos
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo = insn.mnemonic
flags = dict((self.flags_table[k], k) for k in self.flags_table)
val = gef.arch.register(self.flag_register)
taken, reason = False, ""
if mnemo == "beq": taken, reason = bool(val&(1<<flags["equal[7]"])), "E"
elif mnemo == "bne": taken, reason = val&(1<<flags["equal[7]"]) == 0, "!E"
elif mnemo == "ble": taken, reason = bool(val&(1<<flags["equal[7]"])) or bool(val&(1<<flags["less[7]"])), "E || L"
elif mnemo == "blt": taken, reason = bool(val&(1<<flags["less[7]"])), "L"
elif mnemo == "bge": taken, reason = bool(val&(1<<flags["equal[7]"])) or bool(val&(1<<flags["greater[7]"])), "E || G"
elif mnemo == "bgt": taken, reason = bool(val&(1<<flags["greater[7]"])), "G"
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
ra = None
if self.is_ret(insn):
ra = gef.arch.register("$lr")
elif frame.older():
ra = frame.older().pc()
return ra
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
# Ref: https://developer.ibm.com/articles/l-ppc/
_NR_mprotect = 125
insns = [
"addi 1, 1, -16", # 1 = r1 = sp
"stw 0, 0(1)",
"stw 3, 4(1)", # r0 = syscall_code | r3, r4, r5 = args
"stw 4, 8(1)",
"stw 5, 12(1)",
f"li 0, {_NR_mprotect:d}",
f"lis 3, {addr:#x}@h",
f"ori 3, 3, {addr:#x}@l",
f"lis 4, {size:#x}@h",
f"ori 4, 4, {size:#x}@l",
f"li 5, {perm.value:d}",
"sc",
"lwz 0, 0(1)",
"lwz 3, 4(1)",
"lwz 4, 8(1)",
"lwz 5, 12(1)",
"addi 1, 1, 16",
]
return ";".join(insns)
class PowerPC64(PowerPC):
aliases = ("PowerPC64", Elf.Abi.POWERPC64, "PPC64")
arch = "PPC"
mode = "PPC64"
ptrsize = 8
class SPARC(Architecture):
""" Refs:
- https://www.cse.scu.edu/~atkinson/teaching/sp05/259/sparc.pdf
"""
aliases = ("SPARC", Elf.Abi.SPARC)
arch = "SPARC"
mode = ""
all_registers = (
"$g0", "$g1", "$g2", "$g3", "$g4", "$g5", "$g6", "$g7",
"$o0", "$o1", "$o2", "$o3", "$o4", "$o5", "$o7",
"$l0", "$l1", "$l2", "$l3", "$l4", "$l5", "$l6", "$l7",
"$i0", "$i1", "$i2", "$i3", "$i4", "$i5", "$i7",
"$pc", "$npc", "$sp ", "$fp ", "$psr",)
instruction_length = 4
nop_insn = b"\x00\x00\x00\x00" # sethi 0, %g0
return_register = "$i0"
flag_register: str = "$psr"
flags_table = {
23: "negative",
22: "zero",
21: "overflow",
20: "carry",
7: "supervisor",
5: "trap",
}
function_parameters = ("$o0 ", "$o1 ", "$o2 ", "$o3 ", "$o4 ", "$o5 ", "$o7 ",)
syscall_register = "%g1"
syscall_instructions = ("t 0x10",)
def flag_register_to_human(self, val: Optional[int] = None) -> str:
# https://www.gaisler.com/doc/sparcv8.pdf
reg = self.flag_register
if not val:
val = gef.arch.register(reg)
return flags_to_human(val, self.flags_table)
def is_call(self, insn: Instruction) -> bool:
return False
def is_ret(self, insn: Instruction) -> bool:
return insn.mnemonic == "ret"
def is_conditional_branch(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
# http://moss.csc.ncsu.edu/~mueller/codeopt/codeopt00/notes/condbranch.html
branch_mnemos = {
"be", "bne", "bg", "bge", "bgeu", "bgu", "bl", "ble", "blu", "bleu",
"bneg", "bpos", "bvs", "bvc", "bcs", "bcc"
}
return mnemo in branch_mnemos
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo = insn.mnemonic
flags = dict((self.flags_table[k], k) for k in self.flags_table)
val = gef.arch.register(self.flag_register)
taken, reason = False, ""
if mnemo == "be": taken, reason = bool(val&(1<<flags["zero"])), "Z"
elif mnemo == "bne": taken, reason = bool(val&(1<<flags["zero"])) == 0, "!Z"
elif mnemo == "bg": taken, reason = bool(val&(1<<flags["zero"])) == 0 and (val&(1<<flags["negative"]) == 0 or val&(1<<flags["overflow"]) == 0), "!Z && (!N || !O)"
elif mnemo == "bge": taken, reason = val&(1<<flags["negative"]) == 0 or val&(1<<flags["overflow"]) == 0, "!N || !O"
elif mnemo == "bgu": taken, reason = val&(1<<flags["carry"]) == 0 and val&(1<<flags["zero"]) == 0, "!C && !Z"
elif mnemo == "bgeu": taken, reason = val&(1<<flags["carry"]) == 0, "!C"
elif mnemo == "bl": taken, reason = bool(val&(1<<flags["negative"])) and bool(val&(1<<flags["overflow"])), "N && O"
elif mnemo == "blu": taken, reason = bool(val&(1<<flags["carry"])), "C"
elif mnemo == "ble": taken, reason = bool(val&(1<<flags["zero"])) or bool(val&(1<<flags["negative"]) or val&(1<<flags["overflow"])), "Z || (N || O)"
elif mnemo == "bleu": taken, reason = bool(val&(1<<flags["carry"])) or bool(val&(1<<flags["zero"])), "C || Z"
elif mnemo == "bneg": taken, reason = bool(val&(1<<flags["negative"])), "N"
elif mnemo == "bpos": taken, reason = val&(1<<flags["negative"]) == 0, "!N"
elif mnemo == "bvs": taken, reason = bool(val&(1<<flags["overflow"])), "O"
elif mnemo == "bvc": taken, reason = val&(1<<flags["overflow"]) == 0, "!O"
elif mnemo == "bcs": taken, reason = bool(val&(1<<flags["carry"])), "C"
elif mnemo == "bcc": taken, reason = val&(1<<flags["carry"]) == 0, "!C"
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
ra = None
if self.is_ret(insn):
ra = gef.arch.register("$o7")
elif frame.older():
ra = frame.older().pc()
return ra
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
hi = (addr & 0xffff0000) >> 16
lo = (addr & 0x0000ffff)
_NR_mprotect = 125
insns = ["add %sp, -16, %sp",
"st %g1, [ %sp ]", "st %o0, [ %sp + 4 ]",
"st %o1, [ %sp + 8 ]", "st %o2, [ %sp + 12 ]",
f"sethi %hi({hi}), %o0",
f"or %o0, {lo}, %o0",
"clr %o1",
"clr %o2",
f"mov {_NR_mprotect}, %g1",
"t 0x10",
"ld [ %sp ], %g1", "ld [ %sp + 4 ], %o0",
"ld [ %sp + 8 ], %o1", "ld [ %sp + 12 ], %o2",
"add %sp, 16, %sp",]
return "; ".join(insns)
class SPARC64(SPARC):
"""Refs:
- http://math-atlas.sourceforge.net/devel/assembly/abi_sysV_sparc.pdf
- https://cr.yp.to/2005-590/sparcv9.pdf
"""
aliases = ("SPARC64", Elf.Abi.SPARC64)
arch = "SPARC"
mode = "V9"
all_registers = [
"$g0", "$g1", "$g2", "$g3", "$g4", "$g5", "$g6", "$g7",
"$o0", "$o1", "$o2", "$o3", "$o4", "$o5", "$o7",
"$l0", "$l1", "$l2", "$l3", "$l4", "$l5", "$l6", "$l7",
"$i0", "$i1", "$i2", "$i3", "$i4", "$i5", "$i7",
"$pc", "$npc", "$sp", "$fp", "$state", ]
flag_register = "$state" # sparcv9.pdf, 5.1.5.1 (ccr)
flags_table = {
35: "negative",
34: "zero",
33: "overflow",
32: "carry",
}
syscall_instructions = ["t 0x6d"]
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
hi = (addr & 0xffff0000) >> 16
lo = (addr & 0x0000ffff)
_NR_mprotect = 125
insns = ["add %sp, -16, %sp",
"st %g1, [ %sp ]", "st %o0, [ %sp + 4 ]",
"st %o1, [ %sp + 8 ]", "st %o2, [ %sp + 12 ]",
f"sethi %hi({hi}), %o0",
f"or %o0, {lo}, %o0",
"clr %o1",
"clr %o2",
f"mov {_NR_mprotect}, %g1",
"t 0x6d",
"ld [ %sp ], %g1", "ld [ %sp + 4 ], %o0",
"ld [ %sp + 8 ], %o1", "ld [ %sp + 12 ], %o2",
"add %sp, 16, %sp",]
return "; ".join(insns)
class MIPS(Architecture):
aliases: Tuple[Union[str, Elf.Abi], ...] = ("MIPS", Elf.Abi.MIPS)
arch = "MIPS"
mode = "MIPS32"
# https://vhouten.home.xs4all.nl/mipsel/r3000-isa.html
all_registers = (
"$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3",
"$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
"$s0", "$s1", "$s2", "$s3", "$s4", "$s5", "$s6", "$s7",
"$t8", "$t9", "$k0", "$k1", "$s8", "$pc", "$sp", "$hi",
"$lo", "$fir", "$ra", "$gp", )
instruction_length = 4
_ptrsize = 4
nop_insn = b"\x00\x00\x00\x00" # sll $0,$0,0
return_register = "$v0"
flag_register = "$fcsr"
flags_table = {}
function_parameters = ("$a0", "$a1", "$a2", "$a3")
syscall_register = "$v0"
syscall_instructions = ("syscall",)
def flag_register_to_human(self, val: Optional[int] = None) -> str:
return Color.colorify("No flag register", "yellow underline")
def is_call(self, insn: Instruction) -> bool:
return False
def is_ret(self, insn: Instruction) -> bool:
return insn.mnemonic == "jr" and insn.operands[0] == "ra"
def is_conditional_branch(self, insn: Instruction) -> bool:
mnemo = insn.mnemonic
branch_mnemos = {"beq", "bne", "beqz", "bnez", "bgtz", "bgez", "bltz", "blez"}
return mnemo in branch_mnemos
def is_branch_taken(self, insn: Instruction) -> Tuple[bool, str]:
mnemo, ops = insn.mnemonic, insn.operands
taken, reason = False, ""
if mnemo == "beq":
taken, reason = gef.arch.register(ops[0]) == gef.arch.register(ops[1]), "{0[0]} == {0[1]}".format(ops)
elif mnemo == "bne":
taken, reason = gef.arch.register(ops[0]) != gef.arch.register(ops[1]), "{0[0]} != {0[1]}".format(ops)
elif mnemo == "beqz":
taken, reason = gef.arch.register(ops[0]) == 0, "{0[0]} == 0".format(ops)
elif mnemo == "bnez":
taken, reason = gef.arch.register(ops[0]) != 0, "{0[0]} != 0".format(ops)
elif mnemo == "bgtz":
taken, reason = gef.arch.register(ops[0]) > 0, "{0[0]} > 0".format(ops)
elif mnemo == "bgez":
taken, reason = gef.arch.register(ops[0]) >= 0, "{0[0]} >= 0".format(ops)
elif mnemo == "bltz":
taken, reason = gef.arch.register(ops[0]) < 0, "{0[0]} < 0".format(ops)
elif mnemo == "blez":
taken, reason = gef.arch.register(ops[0]) <= 0, "{0[0]} <= 0".format(ops)
return taken, reason
def get_ra(self, insn: Instruction, frame: "gdb.Frame") -> Optional[int]:
ra = None
if self.is_ret(insn):
ra = gef.arch.register("$ra")
elif frame.older():
ra = frame.older().pc()
return ra
@classmethod
def mprotect_asm(cls, addr: int, size: int, perm: Permission) -> str:
_NR_mprotect = 4125
insns = ["addi $sp, $sp, -16",
"sw $v0, 0($sp)", "sw $a0, 4($sp)",
"sw $a3, 8($sp)", "sw $a3, 12($sp)",
f"li $v0, {_NR_mprotect:d}",
f"li $a0, {addr:d}",
f"li $a1, {size:d}",
f"li $a2, {perm.value:d}",
"syscall",
"lw $v0, 0($sp)", "lw $a1, 4($sp)",
"lw $a3, 8($sp)", "lw $a3, 12($sp)",
"addi $sp, $sp, 16",]
return "; ".join(insns)
class MIPS64(MIPS):
aliases = ("MIPS64",)
arch = "MIPS"
mode = "MIPS64"
_ptrsize = 8
@staticmethod
def supports_gdb_arch(gdb_arch: str) -> Optional[bool]:
return gdb_arch.startswith("mips") and gef.binary.e_class == Elf.Class.ELF_64_BITS
def copy_to_clipboard(data: bytes) -> None:
"""Helper function to submit data to the clipboard"""
if sys.platform == "linux":
xclip = which("xclip")
prog = [xclip, "-selection", "clipboard", "-i"]
elif sys.platform == "darwin":
pbcopy = which("pbcopy")
prog = [pbcopy]
else:
raise NotImplementedError("copy: Unsupported OS")
with subprocess.Popen(prog, stdin=subprocess.PIPE) as p:
p.stdin.write(data)
p.stdin.close()
p.wait()
return
def use_stdtype() -> str:
if is_32bit(): return "uint32_t"
elif is_64bit(): return "uint64_t"
return "uint16_t"
def use_default_type() -> str:
if is_32bit(): return "unsigned int"
elif is_64bit(): return "unsigned long"
return "unsigned short"
def use_golang_type() -> str:
if is_32bit(): return "uint32"
elif is_64bit(): return "uint64"
return "uint16"
def use_rust_type() -> str:
if is_32bit(): return "u32"
elif is_64bit(): return "u64"
return "u16"
def to_unsigned_long(v: gdb.Value) -> int:
"""Cast a gdb.Value to unsigned long."""
mask = (1 << 64) - 1
return int(v.cast(gdb.Value(mask).type)) & mask
def get_path_from_info_proc() -> Optional[str]:
for x in gdb.execute("info proc", to_string=True).splitlines():
if x.startswith("exe = "):
return x.split(" = ")[1].replace("'", "")
return None
@deprecated("Use `gef.session.os`")
def get_os() -> str:
return gef.session.os
@lru_cache()
def is_qemu() -> bool:
if not is_remote_debug():
return False
response = gdb.execute("maintenance packet Qqemu.sstepbits", to_string=True, from_tty=False)
return "ENABLE=" in response
@lru_cache()
def is_qemu_usermode() -> bool:
if not is_qemu():
return False
response = gdb.execute("maintenance packet qOffsets", to_string=True, from_tty=False)
return "Text=" in response
@lru_cache()
def is_qemu_system() -> bool:
if not is_qemu():
return False
response = gdb.execute("maintenance packet qOffsets", to_string=True, from_tty=False)
return "received: \"\"" in response
def get_filepath() -> Optional[str]:
"""Return the local absolute path of the file currently debugged."""
if gef.session.remote:
return str(gef.session.remote.lfile.absolute())
if gef.session.file:
return str(gef.session.file.absolute())
return None
def get_function_length(sym: str) -> int:
"""Attempt to get the length of the raw bytes of a function."""
dis = gdb.execute(f"disassemble {sym}", to_string=True).splitlines()
start_addr = int(dis[1].split()[0], 16)
end_addr = int(dis[-2].split()[0], 16)
return end_addr - start_addr
@lru_cache()
def get_info_files() -> List[Zone]:
"""Retrieve all the files loaded by debuggee."""
lines = gdb.execute("info files", to_string=True).splitlines()
infos = []
for line in lines:
line = line.strip()
if not line:
break
if not line.startswith("0x"):
continue
blobs = [x.strip() for x in line.split(" ")]
addr_start = int(blobs[0], 16)
addr_end = int(blobs[2], 16)
section_name = blobs[4]
if len(blobs) == 7:
filename = blobs[6]
else:
filename = get_filepath()
infos.append(Zone(section_name, addr_start, addr_end, filename))
return infos
def process_lookup_address(address: int) -> Optional[Section]:
"""Look up for an address in memory.
Return an Address object if found, None otherwise."""
if not is_alive():
err("Process is not running")
return None
if is_x86():
if is_in_x86_kernel(address):
return None
for sect in gef.memory.maps:
if sect.page_start <= address < sect.page_end:
return sect
return None
@lru_cache()
def process_lookup_path(name: str, perm: Permission = Permission.ALL) -> Optional[Section]:
"""Look up for a path in the process memory mapping.
Return a Section object if found, None otherwise."""
if not is_alive():
err("Process is not running")
return None
for sect in gef.memory.maps:
if name in sect.path and sect.permission & perm:
return sect
return None
@lru_cache()
def file_lookup_name_path(name: str, path: str) -> Optional[Zone]:
"""Look up a file by name and path.
Return a Zone object if found, None otherwise."""
for xfile in get_info_files():
if path == xfile.filename and name == xfile.name:
return xfile
return None
@lru_cache()
def file_lookup_address(address: int) -> Optional[Zone]:
"""Look up for a file by its address.
Return a Zone object if found, None otherwise."""
for info in get_info_files():
if info.zone_start <= address < info.zone_end:
return info
return None
@lru_cache()
def lookup_address(address: int) -> Address:
"""Try to find the address in the process address space.
Return an Address object, with validity flag set based on success."""
sect = process_lookup_address(address)
info = file_lookup_address(address)
if sect is None and info is None:
# i.e. there is no info on this address
return Address(value=address, valid=False)
return Address(value=address, section=sect, info=info)
def xor(data: ByteString, key: str) -> bytearray:
"""Return `data` xor-ed with `key`."""
key_raw = binascii.unhexlify(key.lstrip("0x"))
return bytearray(x ^ y for x, y in zip(data, itertools.cycle(key_raw)))
def is_hex(pattern: str) -> bool:
"""Return whether provided string is a hexadecimal value."""
if not pattern.lower().startswith("0x"):
return False
return len(pattern) % 2 == 0 and all(c in string.hexdigits for c in pattern[2:])
def continue_handler(_: "gdb.Event") -> None:
"""GDB event handler for new object continue cases."""
return
def hook_stop_handler(_: "gdb.StopEvent") -> None:
"""GDB event handler for stop cases."""
reset_all_caches()
gdb.execute("context")
return
def new_objfile_handler(evt: Optional["gdb.NewObjFileEvent"]) -> None:
"""GDB event handler for new object file cases."""
reset_all_caches()
path = evt.new_objfile.filename if evt else gdb.current_progspace().filename
try:
if gef.session.root and path.startswith("target:"):
# If the process is in a container, replace the "target:" prefix
# with the actual root directory of the process.
path = path.replace("target:", str(gef.session.root), 1)
target = pathlib.Path(path)
FileFormatClasses = list(filter(lambda fmtcls: fmtcls.is_valid(target), __registered_file_formats__))
GuessedFileFormatClass : Type[FileFormat] = FileFormatClasses.pop() if len(FileFormatClasses) else Elf
binary = GuessedFileFormatClass(target)
if not gef.binary:
gef.binary = binary
reset_architecture()
else:
gef.session.modules.append(binary)
except FileNotFoundError as fne:
# Linux automatically maps the vDSO into our process, and GDB
# will give us the string 'system-supplied DSO' as a path.
# This is normal, so we shouldn't warn the user about it
if "system-supplied DSO" not in path:
warn(f"Failed to find objfile or not a valid file format: {str(fne)}")
except RuntimeError as re:
warn(f"Not a valid file format: {str(re)}")
return
def exit_handler(_: "gdb.ExitedEvent") -> None:
"""GDB event handler for exit cases."""
global gef
reset_all_caches()
gef.session.qemu_mode = False
if gef.session.remote:
gef.session.remote.close()
del gef.session.remote
gef.session.remote = None
gef.session.remote_initializing = False
return
def memchanged_handler(_: "gdb.MemoryChangedEvent") -> None:
"""GDB event handler for mem changes cases."""
reset_all_caches()
return
def regchanged_handler(_: "gdb.RegisterChangedEvent") -> None:
"""GDB event handler for reg changes cases."""
reset_all_caches()
return
def get_terminal_size() -> Tuple[int, int]:
"""Return the current terminal size."""
if is_debug():
return 600, 100
if platform.system() == "Windows":
from ctypes import create_string_buffer, windll
hStdErr = -12
herr = windll.kernel32.GetStdHandle(hStdErr)
csbi = create_string_buffer(22)
res = windll.kernel32.GetConsoleScreenBufferInfo(herr, csbi)
if res:
_, _, _, _, _, left, top, right, bottom, _, _ = struct.unpack("hhhhHhhhhhh", csbi.raw)
tty_columns = right - left + 1
tty_rows = bottom - top + 1
return tty_rows, tty_columns
else:
return 600, 100
else:
import fcntl
import termios
try:
tty_rows, tty_columns = struct.unpack("hh", fcntl.ioctl(1, termios.TIOCGWINSZ, "1234")) # type: ignore
return tty_rows, tty_columns
except OSError:
return 600, 100
@lru_cache()
def is_64bit() -> bool:
"""Checks if current target is 64bit."""
return gef.arch.ptrsize == 8
@lru_cache()
def is_32bit() -> bool:
"""Checks if current target is 32bit."""
return gef.arch.ptrsize == 4
@lru_cache()
def is_x86_64() -> bool:
"""Checks if current target is x86-64"""
return Elf.Abi.X86_64 in gef.arch.aliases
@lru_cache()
def is_x86_32():
"""Checks if current target is an x86-32"""
return Elf.Abi.X86_32 in gef.arch.aliases
@lru_cache()
def is_x86() -> bool:
return is_x86_32() or is_x86_64()
@lru_cache()
def is_arch(arch: Elf.Abi) -> bool:
return arch in gef.arch.aliases
def reset_architecture(arch: Optional[str] = None) -> None:
"""Sets the current architecture.
If an architecture is explicitly specified by parameter, try to use that one. If this fails, an `OSError`
exception will occur.
If no architecture is specified, then GEF will attempt to determine automatically based on the current
ELF target. If this fails, an `OSError` exception will occur.
"""
global gef
arches = __registered_architectures__
# check if the architecture is forced by parameter
if arch:
try:
gef.arch = arches[arch]()
except KeyError:
raise OSError(f"Specified arch {arch.upper()} is not supported")
return
gdb_arch = get_arch()
preciser_arch = next((a for a in arches.values() if a.supports_gdb_arch(gdb_arch)), None)
if preciser_arch:
gef.arch = preciser_arch()
return
# last resort, use the info from elf header to find it from the known architectures
try:
arch_name = gef.binary.e_machine if gef.binary else gdb_arch
gef.arch = arches[arch_name]()
except KeyError:
raise OSError(f"CPU type is currently not supported: {get_arch()}")
return
@lru_cache()
def cached_lookup_type(_type: str) -> Optional[gdb.Type]:
try:
return gdb.lookup_type(_type).strip_typedefs()
except RuntimeError:
return None
@deprecated("Use `gef.arch.ptrsize` instead")
def get_memory_alignment(in_bits: bool = False) -> int:
"""Try to determine the size of a pointer on this system.
First, try to parse it out of the ELF header.
Next, use the size of `size_t`.
Finally, try the size of $pc.
If `in_bits` is set to True, the result is returned in bits, otherwise in
bytes."""
res = cached_lookup_type("size_t")
if res is not None:
return res.sizeof if not in_bits else res.sizeof * 8
try:
return gdb.parse_and_eval("$pc").type.sizeof
except:
pass
raise OSError("GEF is running under an unsupported mode")
def clear_screen(tty: str = "") -> None:
"""Clear the screen."""
global gef
if not tty:
gdb.execute("shell clear -x")
return
# Since the tty can be closed at any time, a PermissionError exception can
# occur when `clear_screen` is called. We handle this scenario properly
try:
with open(tty, "wt") as f:
f.write("\x1b[H\x1b[J")
except PermissionError:
gef.ui.redirect_fd = None
gef.config["context.redirect"] = ""
return
def format_address(addr: int) -> str:
"""Format the address according to its size."""
memalign_size = gef.arch.ptrsize
addr = align_address(addr)
if memalign_size == 4:
return f"0x{addr:08x}"
return f"0x{addr:016x}"
def format_address_spaces(addr: int, left: bool = True) -> str:
"""Format the address according to its size, but with spaces instead of zeroes."""
width = gef.arch.ptrsize * 2 + 2
addr = align_address(addr)
if not left:
return f"{addr:#x}".rjust(width)
return f"{addr:#x}".ljust(width)
def align_address(address: int) -> int:
"""Align the provided address to the process's native length."""
if gef.arch.ptrsize == 4:
return address & 0xFFFFFFFF
return address & 0xFFFFFFFFFFFFFFFF
def align_address_to_size(address: int, align: int) -> int:
"""Align the address to the given size."""
return address + ((align - (address % align)) % align)
def align_address_to_page(address: int) -> int:
"""Align the address to a page."""
a = align_address(address) >> DEFAULT_PAGE_ALIGN_SHIFT
return a << DEFAULT_PAGE_ALIGN_SHIFT
def parse_address(address: str) -> int:
"""Parse an address and return it as an Integer."""
if is_hex(address):
return int(address, 16)
return to_unsigned_long(gdb.parse_and_eval(address))
def is_in_x86_kernel(address: int) -> bool:
address = align_address(address)
memalign = gef.arch.ptrsize*8 - 1
return (address >> memalign) == 0xF
def is_remote_debug() -> bool:
""""Return True is the current debugging session is running through GDB remote session."""
return gef.session.remote_initializing or gef.session.remote is not None
def de_bruijn(alphabet: bytes, n: int) -> Generator[str, None, None]:
"""De Bruijn sequence for alphabet and subsequences of length n (for compat. w/ pwnlib)."""
k = len(alphabet)
a = [0] * k * n
def db(t: int, p: int) -> Generator[str, None, None]:
if t > n:
if n % p == 0:
for j in range(1, p + 1):
yield alphabet[a[j]]
else:
a[t] = a[t - p]
yield from db(t + 1, p)
for j in range(a[t - p] + 1, k):
a[t] = j
yield from db(t + 1, t)
return db(1, 1)
def generate_cyclic_pattern(length: int, cycle: int = 4) -> bytearray:
"""Create a `length` byte bytearray of a de Bruijn cyclic pattern."""
charset = bytearray(b"abcdefghijklmnopqrstuvwxyz")
return bytearray(itertools.islice(de_bruijn(charset, cycle), length))
def safe_parse_and_eval(value: str) -> Optional["gdb.Value"]:
"""GEF wrapper for gdb.parse_and_eval(): this function returns None instead of raising
gdb.error if the eval failed."""
try:
return gdb.parse_and_eval(value)
except gdb.error:
pass
return None
@lru_cache()
def dereference(addr: int) -> Optional["gdb.Value"]:
"""GEF wrapper for gdb dereference function."""
try:
ulong_t = cached_lookup_type(use_stdtype()) or \
cached_lookup_type(use_default_type()) or \
cached_lookup_type(use_golang_type()) or \
cached_lookup_type(use_rust_type())
unsigned_long_type = ulong_t.pointer()
res = gdb.Value(addr).cast(unsigned_long_type).dereference()
# GDB does lazy fetch by default so we need to force access to the value
res.fetch_lazy()
return res
except gdb.MemoryError:
pass
return None
def gef_convenience(value: Union[str, bytes]) -> str:
"""Defines a new convenience value."""
global gef
var_name = f"$_gef{gef.session.convenience_vars_index:d}"
gef.session.convenience_vars_index += 1
if isinstance(value, str):
gdb.execute(f"""set {var_name} = "{value}" """)
elif isinstance(value, bytes):
value_as_array = "{" + ", ".join(["%#.02x" % x for x in value]) + "}"
gdb.execute(f"""set {var_name} = {value_as_array} """)
else:
raise TypeError
return var_name
def parse_string_range(s: str) -> Iterator[int]:
"""Parses an address range (e.g. 0x400000-0x401000)"""
addrs = s.split("-")
return map(lambda x: int(x, 16), addrs)
@lru_cache()
def is_syscall(instruction: Union[Instruction,int]) -> bool:
"""Checks whether an instruction or address points to a system call."""
if isinstance(instruction, int):
instruction = gef_current_instruction(instruction)
insn_str = instruction.mnemonic
if len(instruction.operands):
insn_str += f" {', '.join(instruction.operands)}"
return insn_str in gef.arch.syscall_instructions
#
# Deprecated API
#
@deprecated("Use `gef.session.pie_breakpoints[num]`")
def gef_get_pie_breakpoint(num: int) -> "PieVirtualBreakpoint":
return gef.session.pie_breakpoints[num]
@deprecated("Use `str(gef.arch.endianness)` instead")
def endian_str() -> str:
return str(gef.arch.endianness)
@deprecated("Use `gef.config[key]`")
def get_gef_setting(name: str) -> Any:
return gef.config[name]
@deprecated("Use `gef.config[key] = value`")
def set_gef_setting(name: str, value: Any) -> None:
gef.config[name] = value
return
@deprecated("Use `gef.session.pagesize`")
def gef_getpagesize() -> int:
return gef.session.pagesize
@deprecated("Use `gef.session.canary`")
def gef_read_canary() -> Optional[Tuple[int, int]]:
return gef.session.canary
@deprecated("Use `gef.session.pid`")
def get_pid() -> int:
return gef.session.pid
@deprecated("Use `gef.session.file.name`")
def get_filename() -> str:
return gef.session.file.name
@deprecated("Use `gef.heap.main_arena`")
def get_glibc_arena() -> Optional[GlibcArena]:
return gef.heap.main_arena
@deprecated("Use `gef.arch.register(regname)`")
def get_register(regname) -> Optional[int]:
return gef.arch.register(regname)
@deprecated("Use `gef.memory.maps`")
def get_process_maps() -> List[Section]:
return gef.memory.maps
@deprecated("Use `reset_architecture`")
def set_arch(arch: Optional[str] = None, _: Optional[str] = None) -> None:
return reset_architecture(arch)
#
# GDB event hooking
#
@only_if_events_supported("cont")
def gef_on_continue_hook(func: Callable[["gdb.ThreadEvent"], None]) -> None:
gdb.events.cont.connect(func)
@only_if_events_supported("cont")
def gef_on_continue_unhook(func: Callable[["gdb.ThreadEvent"], None]) -> None:
gdb.events.cont.disconnect(func)
@only_if_events_supported("stop")
def gef_on_stop_hook(func: Callable[["gdb.StopEvent"], None]) -> None:
gdb.events.stop.connect(func)
@only_if_events_supported("stop")
def gef_on_stop_unhook(func: Callable[["gdb.StopEvent"], None]) -> None:
gdb.events.stop.disconnect(func)
@only_if_events_supported("exited")
def gef_on_exit_hook(func: Callable[["gdb.ExitedEvent"], None]) -> None:
gdb.events.exited.connect(func)
@only_if_events_supported("exited")
def gef_on_exit_unhook(func: Callable[["gdb.ExitedEvent"], None]) -> None:
gdb.events.exited.disconnect(func)
@only_if_events_supported("new_objfile")
def gef_on_new_hook(func: Callable[["gdb.NewObjFileEvent"], None]) -> None:
gdb.events.new_objfile.connect(func)
@only_if_events_supported("new_objfile")
def gef_on_new_unhook(func: Callable[["gdb.NewObjFileEvent"], None]) -> None:
gdb.events.new_objfile.disconnect(func)
@only_if_events_supported("clear_objfiles")
def gef_on_unload_objfile_hook(func: Callable[["gdb.ClearObjFilesEvent"], None]) -> None:
gdb.events.clear_objfiles.connect(func)
@only_if_events_supported("clear_objfiles")
def gef_on_unload_objfile_unhook(func: Callable[["gdb.ClearObjFilesEvent"], None]) -> None:
gdb.events.clear_objfiles.disconnect(func)
@only_if_events_supported("memory_changed")
def gef_on_memchanged_hook(func: Callable[["gdb.MemoryChangedEvent"], None]) -> None:
gdb.events.memory_changed.connect(func)
@only_if_events_supported("memory_changed")
def gef_on_memchanged_unhook(func: Callable[["gdb.MemoryChangedEvent"], None]) -> None:
gdb.events.memory_changed.disconnect(func)
@only_if_events_supported("register_changed")
def gef_on_regchanged_hook(func: Callable[["gdb.RegisterChangedEvent"], None]) -> None:
gdb.events.register_changed.connect(func)
@only_if_events_supported("register_changed")
def gef_on_regchanged_unhook(func: Callable[["gdb.RegisterChangedEvent"], None]) -> None:
gdb.events.register_changed.disconnect(func)
#
# Virtual breakpoints
#
class PieVirtualBreakpoint:
"""PIE virtual breakpoint (not real breakpoint)."""
def __init__(self, set_func: Callable[[int], str], vbp_num: int, addr: int) -> None:
# set_func(base): given a base address return a
# "set breakpoint" gdb command string
self.set_func = set_func
self.vbp_num = vbp_num
# breakpoint num, 0 represents not instantiated yet
self.bp_num = 0
self.bp_addr = 0
# this address might be a symbol, just to know where to break
if isinstance(addr, int):
self.addr: Union[int, str] = hex(addr)
else:
self.addr = addr
return
def instantiate(self, base: int) -> None:
if self.bp_num:
self.destroy()
try:
res = gdb.execute(self.set_func(base), to_string=True)
except gdb.error as e:
err(e)
return
if "Breakpoint" not in res:
err(res)
return
res_list = res.split()
self.bp_num = res_list[1]
self.bp_addr = res_list[3]
return
def destroy(self) -> None:
if not self.bp_num:
err("Destroy PIE breakpoint not even set")
return
gdb.execute(f"delete {self.bp_num}")
self.bp_num = 0
return
#
# Breakpoints
#
class FormatStringBreakpoint(gdb.Breakpoint):
"""Inspect stack for format string."""
def __init__(self, spec: str, num_args: int) -> None:
super().__init__(spec, type=gdb.BP_BREAKPOINT, internal=False)
self.num_args = num_args
self.enabled = True
return
def stop(self) -> bool:
reset_all_caches()
msg = []
ptr, addr = gef.arch.get_ith_parameter(self.num_args)
addr = lookup_address(addr)
if not addr.valid:
return False
if addr.section.is_writable():
content = gef.memory.read_cstring(addr.value)
name = addr.info.name if addr.info else addr.section.path
msg.append(Color.colorify("Format string helper", "yellow bold"))
msg.append(f"Possible insecure format string: {self.location}('{ptr}' {RIGHT_ARROW} {addr.value:#x}: '{content}')")
msg.append(f"Reason: Call to '{self.location}()' with format string argument in position "
f"#{self.num_args:d} is in page {addr.section.page_start:#x} ({name}) that has write permission")
push_context_message("warn", "\n".join(msg))
return True
return False
class StubBreakpoint(gdb.Breakpoint):
"""Create a breakpoint to permanently disable a call (fork/alarm/signal/etc.)."""
def __init__(self, func: str, retval: Optional[int]) -> None:
super().__init__(func, gdb.BP_BREAKPOINT, internal=False)
self.func = func
self.retval = retval
m = f"All calls to '{self.func}' will be skipped"
if self.retval is not None:
m += f" (with return value set to {self.retval:#x})"
info(m)
return
def stop(self) -> bool:
gdb.execute(f"return (unsigned int){self.retval:#x}")
ok(f"Ignoring call to '{self.func}' "
f"(setting return value to {self.retval:#x})")
return False
class ChangePermissionBreakpoint(gdb.Breakpoint):
"""When hit, this temporary breakpoint will restore the original code, and position
$pc correctly."""
def __init__(self, loc: str, code: ByteString, pc: int) -> None:
super().__init__(loc, gdb.BP_BREAKPOINT, internal=False)
self.original_code = code
self.original_pc = pc
return
def stop(self) -> bool:
info("Restoring original context")
gef.memory.write(self.original_pc, self.original_code, len(self.original_code))
info("Restoring $pc")
gdb.execute(f"set $pc = {self.original_pc:#x}")
return True
class TraceMallocBreakpoint(gdb.Breakpoint):
"""Track allocations done with malloc() or calloc()."""
def __init__(self, name: str) -> None:
super().__init__(name, gdb.BP_BREAKPOINT, internal=True)
self.silent = True
self.name = name
return
def stop(self) -> bool:
reset_all_caches()
_, size = gef.arch.get_ith_parameter(0)
self.retbp = TraceMallocRetBreakpoint(size, self.name)
return False
class TraceMallocRetBreakpoint(gdb.FinishBreakpoint):
"""Internal temporary breakpoint to retrieve the return value of malloc()."""
def __init__(self, size: int, name: str) -> None:
super().__init__(gdb.newest_frame(), internal=True)
self.size = size
self.name = name
self.silent = True
return
def stop(self) -> bool:
if self.return_value:
loc = int(self.return_value)
else:
loc = parse_address(gef.arch.return_register)
size = self.size
ok(f"{Color.colorify('Heap-Analysis', 'yellow bold')} - {self.name}({size})={loc:#x}")
check_heap_overlap = gef.config["heap-analysis-helper.check_heap_overlap"]
# pop from free-ed list if it was in it
if gef.session.heap_freed_chunks:
idx = 0
for item in gef.session.heap_freed_chunks:
addr = item[0]
if addr == loc:
gef.session.heap_freed_chunks.remove(item)
continue
idx += 1
# pop from uaf watchlist
if gef.session.heap_uaf_watchpoints:
idx = 0
for wp in gef.session.heap_uaf_watchpoints:
wp_addr = wp.address
if loc <= wp_addr < loc + size:
gef.session.heap_uaf_watchpoints.remove(wp)
wp.enabled = False
continue
idx += 1
item = (loc, size)
if check_heap_overlap:
# seek all the currently allocated chunks, read their effective size and check for overlap
msg = []
align = gef.arch.ptrsize
for chunk_addr, _ in gef.session.heap_allocated_chunks:
current_chunk = GlibcChunk(chunk_addr)
current_chunk_size = current_chunk.size
if chunk_addr <= loc < chunk_addr + current_chunk_size:
offset = loc - chunk_addr - 2*align
if offset < 0: continue # false positive, discard
msg.append(Color.colorify("Heap-Analysis", "yellow bold"))
msg.append("Possible heap overlap detected")
msg.append(f"Reason {RIGHT_ARROW} new allocated chunk {loc:#x} (of size {size:d}) overlaps in-used chunk {chunk_addr:#x} (of size {current_chunk_size:#x})")
msg.append(f"Writing {offset:d} bytes from {chunk_addr:#x} will reach chunk {loc:#x}")
msg.append(f"Payload example for chunk {chunk_addr:#x} (to overwrite {loc:#x} headers):")
msg.append(" data = 'A'*{0:d} + 'B'*{1:d} + 'C'*{1:d}".format(offset, align))
push_context_message("warn", "\n".join(msg))
return True
# add it to alloc-ed list
gef.session.heap_allocated_chunks.append(item)
return False
class TraceReallocBreakpoint(gdb.Breakpoint):
"""Track re-allocations done with realloc()."""
def __init__(self) -> None:
super().__init__("__libc_realloc", gdb.BP_BREAKPOINT, internal=True)
self.silent = True
return
def stop(self) -> bool:
_, ptr = gef.arch.get_ith_parameter(0)
_, size = gef.arch.get_ith_parameter(1)
self.retbp = TraceReallocRetBreakpoint(ptr, size)
return False
class TraceReallocRetBreakpoint(gdb.FinishBreakpoint):
"""Internal temporary breakpoint to retrieve the return value of realloc()."""
def __init__(self, ptr: int, size: int) -> None:
super().__init__(gdb.newest_frame(), internal=True)
self.ptr = ptr
self.size = size
self.silent = True
return
def stop(self) -> bool:
if self.return_value:
newloc = int(self.return_value)
else:
newloc = parse_address(gef.arch.return_register)
if newloc != self:
ok("{} - realloc({:#x}, {})={}".format(Color.colorify("Heap-Analysis", "yellow bold"),
self.ptr, self.size,
Color.colorify(f"{newloc:#x}", "green"),))
else:
ok("{} - realloc({:#x}, {})={}".format(Color.colorify("Heap-Analysis", "yellow bold"),
self.ptr, self.size,
Color.colorify(f"{newloc:#x}", "red"),))
item = (newloc, self.size)
try:
# check if item was in alloc-ed list
idx = [x for x, y in gef.session.heap_allocated_chunks].index(self.ptr)
# if so pop it out
item = gef.session.heap_allocated_chunks.pop(idx)
except ValueError:
if is_debug():
warn(f"Chunk {self.ptr:#x} was not in tracking list")
finally:
# add new item to alloc-ed list
gef.session.heap_allocated_chunks.append(item)
return False
class TraceFreeBreakpoint(gdb.Breakpoint):
"""Track calls to free() and attempts to detect inconsistencies."""
def __init__(self) -> None:
super().__init__("__libc_free", gdb.BP_BREAKPOINT, internal=True)
self.silent = True
return
def stop(self) -> bool:
reset_all_caches()
_, addr = gef.arch.get_ith_parameter(0)
msg = []
check_free_null = gef.config["heap-analysis-helper.check_free_null"]
check_double_free = gef.config["heap-analysis-helper.check_double_free"]
check_weird_free = gef.config["heap-analysis-helper.check_weird_free"]
check_uaf = gef.config["heap-analysis-helper.check_uaf"]
ok(f"{Color.colorify('Heap-Analysis', 'yellow bold')} - free({addr:#x})")
if addr == 0:
if check_free_null:
msg.append(Color.colorify("Heap-Analysis", "yellow bold"))
msg.append(f"Attempting to free(NULL) at {gef.arch.pc:#x}")
msg.append("Reason: if NULL page is allocatable, this can lead to code execution.")
push_context_message("warn", "\n".join(msg))
return True
return False
if addr in [x for (x, y) in gef.session.heap_freed_chunks]:
if check_double_free:
msg.append(Color.colorify("Heap-Analysis", "yellow bold"))
msg.append(f"Double-free detected {RIGHT_ARROW} free({addr:#x}) is called at {gef.arch.pc:#x} but is already in the free-ed list")
msg.append("Execution will likely crash...")
push_context_message("warn", "\n".join(msg))
return True
return False
# if here, no error
# 1. move alloc-ed item to free list
try:
# pop from alloc-ed list
idx = [x for x, y in gef.session.heap_allocated_chunks].index(addr)
item = gef.session.heap_allocated_chunks.pop(idx)
except ValueError:
if check_weird_free:
msg.append(Color.colorify("Heap-Analysis", "yellow bold"))
msg.append("Heap inconsistency detected:")
msg.append(f"Attempting to free an unknown value: {addr:#x}")
push_context_message("warn", "\n".join(msg))
return True
return False
# 2. add it to free-ed list
gef.session.heap_freed_chunks.append(item)
self.retbp = None
if check_uaf:
# 3. (opt.) add a watchpoint on pointer
self.retbp = TraceFreeRetBreakpoint(addr)
return False
class TraceFreeRetBreakpoint(gdb.FinishBreakpoint):
"""Internal temporary breakpoint to track free()d values."""
def __init__(self, addr: int) -> None:
super().__init__(gdb.newest_frame(), internal=True)
self.silent = True
self.addr = addr
return
def stop(self) -> bool:
reset_all_caches()
wp = UafWatchpoint(self.addr)
gef.session.heap_uaf_watchpoints.append(wp)
return False
class UafWatchpoint(gdb.Breakpoint):
"""Custom watchpoints set TraceFreeBreakpoint() to monitor free()d pointers being used."""
def __init__(self, addr: int) -> None:
super().__init__(f"*{addr:#x}", gdb.BP_WATCHPOINT, internal=True)
self.address = addr
self.silent = True
self.enabled = True
return
def stop(self) -> bool:
"""If this method is triggered, we likely have a UaF. Break the execution and report it."""
reset_all_caches()
frame = gdb.selected_frame()
if frame.name() in ("_int_malloc", "malloc_consolidate", "__libc_calloc", ):
return False
# software watchpoints stop after the next statement (see
# https://sourceware.org/gdb/onlinedocs/gdb/Set-Watchpoints.html)
pc = gdb_get_nth_previous_instruction_address(gef.arch.pc, 2)
insn = gef_current_instruction(pc)
msg = []
msg.append(Color.colorify("Heap-Analysis", "yellow bold"))
msg.append(f"Possible Use-after-Free in '{get_filepath()}': "
f"pointer {self.address:#x} was freed, but is attempted to be used at {pc:#x}")
msg.append(f"{insn.address:#x} {insn.mnemonic} {Color.yellowify(', '.join(insn.operands))}")
push_context_message("warn", "\n".join(msg))
return True
class EntryBreakBreakpoint(gdb.Breakpoint):
"""Breakpoint used internally to stop execution at the most convenient entry point."""
def __init__(self, location: str) -> None:
super().__init__(location, gdb.BP_BREAKPOINT, internal=True, temporary=True)
self.silent = True
return
def stop(self) -> bool:
reset_all_caches()
return True
class NamedBreakpoint(gdb.Breakpoint):
"""Breakpoint which shows a specified name, when hit."""
def __init__(self, location: str, name: str) -> None:
super().__init__(spec=location, type=gdb.BP_BREAKPOINT, internal=False, temporary=False)
self.name = name
self.loc = location
return
def stop(self) -> bool:
reset_all_caches()
push_context_message("info", f"Hit breakpoint {self.loc} ({Color.colorify(self.name, 'red bold')})")
return True
#
# Context Panes
#
def register_external_context_pane(pane_name: str, display_pane_function: Callable[[], None], pane_title_function: Callable[[], Optional[str]], condition : Optional[Callable[[], bool]] = None) -> None:
"""
Registering function for new GEF Context View.
pane_name: a string that has no spaces (used in settings)
display_pane_function: a function that uses gef_print() to print strings
pane_title_function: a function that returns a string or None, which will be displayed as the title.
If None, no title line is displayed.
condition: an optional callback: if not None, the callback will be executed first. If it returns true,
then only the pane title and content will displayed. Otherwise, it's simply skipped.
Example usage for a simple text to show when we hit a syscall:
def only_syscall(): return gef_current_instruction(gef.arch.pc).is_syscall()
def display_pane():
gef_print("Wow, I am a context pane!")
def pane_title():
return "example:pane"
register_external_context_pane("example_pane", display_pane, pane_title, only_syscall)
"""
gef.gdb.add_context_pane(pane_name, display_pane_function, pane_title_function, condition)
return
#
# Commands
#
@deprecated("Use `register()`, and inherit from `GenericCommand` instead")
def register_external_command(cls: Type["GenericCommand"]) -> Type["GenericCommand"]:
"""Registering function for new GEF (sub-)command to GDB."""
return cls
@deprecated("Use `register()`, and inherit from `GenericCommand` instead")
def register_command(cls: Type["GenericCommand"]) -> Type["GenericCommand"]:
"""Decorator for registering new GEF (sub-)command to GDB."""
return cls
@deprecated("")
def register_priority_command(cls: Type["GenericCommand"]) -> Type["GenericCommand"]:
"""Decorator for registering new command with priority, meaning that it must
loaded before the other generic commands."""
return cls
def register(cls: Union[Type["GenericCommand"], Type["GenericFunction"]]) -> Union[Type["GenericCommand"], Type["GenericFunction"]]:
global __registered_commands__, __registered_functions__
if issubclass(cls, GenericCommand):
assert( hasattr(cls, "_cmdline_"))
assert( hasattr(cls, "do_invoke"))
assert( all(map(lambda x: x._cmdline_ != cls._cmdline_, __registered_commands__)))
__registered_commands__.add(cls)
return cls
if issubclass(cls, GenericFunction):
assert( hasattr(cls, "_function_"))
assert( hasattr(cls, "invoke"))
assert( all(map(lambda x: x._function_ != cls._function_, __registered_functions__)))
__registered_functions__.add(cls)
return cls
raise TypeError(f"`{cls.__class__}` is an illegal class for `register`")
class GenericCommand(gdb.Command):
"""This is an abstract class for invoking commands, should not be instantiated."""
_cmdline_: str
_syntax_: str
_example_: Union[str, List[str]] = ""
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
attributes = ("_cmdline_", "_syntax_", )
if not all(map(lambda x: hasattr(cls, x), attributes)):
raise NotImplementedError
def __init__(self, *args: Any, **kwargs: Any) -> None:
self.pre_load()
syntax = Color.yellowify("\nSyntax: ") + self._syntax_
example = Color.yellowify("\nExamples: \n\t")
if isinstance(self._example_, list):
example += "\n\t".join(self._example_)
elif isinstance(self._example_, str):
example += self._example_
self.__doc__ = self.__doc__.replace(" "*4, "") + syntax + example
self.repeat = False
self.repeat_count = 0
self.__last_command = None
command_type = kwargs.setdefault("command", gdb.COMMAND_OBSCURE)
complete_type = kwargs.setdefault("complete", gdb.COMPLETE_NONE)
prefix = kwargs.setdefault("prefix", False)
super().__init__(self._cmdline_, command_type, complete_type, prefix)
self.post_load()
return
def invoke(self, args: str, from_tty: bool) -> None:
try:
argv = gdb.string_to_argv(args)
self.__set_repeat_count(argv, from_tty)
bufferize(self.do_invoke)(argv)
except Exception as e:
# Note: since we are intercepting cleaning exceptions here, commands preferably should avoid
# catching generic Exception, but rather specific ones. This is allows a much cleaner use.
if is_debug():
show_last_exception()
else:
err(f"Command '{self._cmdline_}' failed to execute properly, reason: {e}")
return
def usage(self) -> None:
err(f"Syntax\n{self._syntax_}")
return
def do_invoke(self, argv: List[str]) -> None:
raise NotImplementedError
def pre_load(self) -> None:
return
def post_load(self) -> None:
return
def __get_setting_name(self, name: str) -> str:
clsname = self.__class__._cmdline_.replace(" ", "-")
return f"{clsname}.{name}"
def __iter__(self) -> Generator[str, None, None]:
for key in gef.config.keys():
if key.startswith(self._cmdline_):
yield key.replace(f"{self._cmdline_}.", "", 1)
@property
def settings(self) -> List[str]:
"""Return the list of settings for this command."""
return list(iter(self))
@deprecated(f"Use `self[setting_name]` instead")
def get_setting(self, name: str) -> Any:
return self.__getitem__(name)
def __getitem__(self, name: str) -> Any:
key = self.__get_setting_name(name)
return gef.config[key]
@deprecated(f"Use `setting_name in self` instead")
def has_setting(self, name: str) -> bool:
return self.__contains__(name)
def __contains__(self, name: str) -> bool:
return self.__get_setting_name(name) in gef.config
@deprecated(f"Use `self[setting_name] = value` instead")
def add_setting(self, name: str, value: Tuple[Any, type, str], description: str = "") -> None:
return self.__setitem__(name, (value, type(value), description))
def __setitem__(self, name: str, value: Union[Any, Tuple[Any, str]]) -> None:
# make sure settings are always associated to the root command (which derives from GenericCommand)
if "GenericCommand" not in [x.__name__ for x in self.__class__.__bases__]:
return
key = self.__get_setting_name(name)
if key in gef.config:
setting = gef.config.raw_entry(key)
setting.value = value
else:
if len(value) == 1:
gef.config[key] = GefSetting(value[0])
elif len(value) == 2:
gef.config[key] = GefSetting(value[0], description=value[1])
return
@deprecated(f"Use `del self[setting_name]` instead")
def del_setting(self, name: str) -> None:
return self.__delitem__(name)
def __delitem__(self, name: str) -> None:
del gef.config[self.__get_setting_name(name)]
return
def __set_repeat_count(self, argv: List[str], from_tty: bool) -> None:
if not from_tty:
self.repeat = False
self.repeat_count = 0
return
command = gdb.execute("show commands", to_string=True).strip().split("\n")[-1]
self.repeat = self.__last_command == command
self.repeat_count = self.repeat_count + 1 if self.repeat else 0
self.__last_command = command
return
@register
class VersionCommand(GenericCommand):
"""Display GEF version info."""
_cmdline_ = "version"
_syntax_ = f"{_cmdline_}"
_example_ = f"{_cmdline_}"
def do_invoke(self, argv: List[str]) -> None:
gef_fpath = pathlib.Path(inspect.stack()[0][1]).expanduser().absolute()
gef_dir = gef_fpath.parent
with gef_fpath.open("rb") as f:
gef_hash = hashlib.sha256(f.read()).hexdigest()
if os.access(f"{gef_dir}/.git", os.X_OK):
ver = subprocess.check_output("git log --format='%H' -n 1 HEAD", cwd=gef_dir, shell=True).decode("utf8").strip()
extra = "dirty" if len(subprocess.check_output("git ls-files -m", cwd=gef_dir, shell=True).decode("utf8").strip()) else "clean"
gef_print(f"GEF: rev:{ver} (Git - {extra})")
else:
gef_blob_hash = subprocess.check_output(f"git hash-object {gef_fpath}", shell=True).decode().strip()
gef_print("GEF: (Standalone)")
gef_print(f"Blob Hash({gef_fpath}): {gef_blob_hash}")
gef_print(f"SHA256({gef_fpath}): {gef_hash}")
gef_print(f"GDB: {gdb.VERSION}")
py_ver = f"{sys.version_info.major:d}.{sys.version_info.minor:d}"
gef_print(f"GDB-Python: {py_ver}")
if "full" in argv:
gef_print(f"Loaded commands: {', '.join(gef.gdb.loaded_command_names)}")
return
@register
class PrintFormatCommand(GenericCommand):
"""Print bytes format in commonly used formats, such as literals in high level languages."""
valid_formats = ("py", "c", "js", "asm", "hex", "bytearray")
valid_bitness = (8, 16, 32, 64)
_cmdline_ = "print-format"
_aliases_ = ["pf",]
_syntax_ = (f"{_cmdline_} [--lang LANG] [--bitlen SIZE] [(--length,-l) LENGTH] [--clip] LOCATION"
f"\t--lang LANG specifies the output format for programming language (available: {valid_formats!s}, default 'py')."
f"\t--bitlen SIZE specifies size of bit (possible values: {valid_bitness!s}, default is 8)."
"\t--length LENGTH specifies length of array (default is 256)."
"\t--clip The output data will be copied to clipboard"
"\tLOCATION specifies where the address of bytes is stored.")
_example_ = f"{_cmdline_} --lang py -l 16 $rsp"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
self["max_size_preview"] = (10, "max size preview of bytes")
return
@property
def format_matrix(self) -> Dict[int, Tuple[str, str, str]]:
# `gef.arch.endianness` is a runtime property, should not be defined as a class property
return {
8: (f"{gef.arch.endianness}B", "char", "db"),
16: (f"{gef.arch.endianness}H", "short", "dw"),
32: (f"{gef.arch.endianness}I", "int", "dd"),
64: (f"{gef.arch.endianness}Q", "long long", "dq"),
}
@only_if_gdb_running
@parse_arguments({"location": "$pc", }, {("--length", "-l"): 256, "--bitlen": 0, "--lang": "py", "--clip": True,})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
"""Default value for print-format command."""
args: argparse.Namespace = kwargs["arguments"]
args.bitlen = args.bitlen or gef.arch.ptrsize * 2
valid_bitlens = self.format_matrix.keys()
if args.bitlen not in valid_bitlens:
err(f"Size of bit must be in: {valid_bitlens!s}")
return
if args.lang not in self.valid_formats:
err(f"Language must be in: {self.valid_formats!s}")
return
start_addr = parse_address(args.location)
size = int(args.bitlen / 8)
end_addr = start_addr + args.length * size
fmt = self.format_matrix[args.bitlen][0]
data = []
if args.lang != "bytearray":
for addr in range(start_addr, end_addr, size):
value = struct.unpack(fmt, gef.memory.read(addr, size))[0]
data += [value]
sdata = ", ".join(map(hex, data))
else:
sdata = ""
if args.lang == "bytearray":
data = gef.memory.read(start_addr, args.length)
preview = str(data[0:self["max_size_preview"]])
out = f"Saved data {preview}... in '{gef_convenience(data)}'"
elif args.lang == "py":
out = f"buf = [{sdata}]"
elif args.lang == "c":
c_type = self.format_matrix[args.bitlen][1]
out = f"unsigned {c_type} buf[{args.length}] = {{{sdata}}};"
elif args.lang == "js":
out = f"var buf = [{sdata}]"
elif args.lang == "asm":
asm_type = self.format_matrix[args.bitlen][2]
out = "buf {0} {1}".format(asm_type, sdata)
elif args.lang == "hex":
out = binascii.hexlify(gef.memory.read(start_addr, end_addr-start_addr)).decode()
else:
raise ValueError(f"Invalid format: {args.lang}")
if args.clip:
if copy_to_clipboard(gef_pybytes(out)):
info("Copied to clipboard")
else:
warn("There's a problem while copying")
gef_print(out)
return
@register
class PieCommand(GenericCommand):
"""PIE breakpoint support."""
_cmdline_ = "pie"
_syntax_ = f"{_cmdline_} (breakpoint|info|delete|run|attach|remote)"
def __init__(self) -> None:
super().__init__(prefix=True)
return
def do_invoke(self, argv: List[str]) -> None:
if not argv:
self.usage()
return
@register
class PieBreakpointCommand(GenericCommand):
"""Set a PIE breakpoint at an offset from the target binaries base address."""
_cmdline_ = "pie breakpoint"
_syntax_ = f"{_cmdline_} OFFSET"
@parse_arguments({"offset": ""}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not args.offset:
self.usage()
return
addr = parse_address(args.offset)
self.set_pie_breakpoint(lambda base: f"b *{base + addr}", addr)
# When the process is already on, set real breakpoints immediately
if is_alive():
vmmap = gef.memory.maps
base_address = [x.page_start for x in vmmap if x.path == get_filepath()][0]
for bp_ins in gef.session.pie_breakpoints.values():
bp_ins.instantiate(base_address)
return
@staticmethod
def set_pie_breakpoint(set_func: Callable[[int], str], addr: int) -> None:
gef.session.pie_breakpoints[gef.session.pie_counter] = PieVirtualBreakpoint(set_func, gef.session.pie_counter, addr)
gef.session.pie_counter += 1
return
@register
class PieInfoCommand(GenericCommand):
"""Display breakpoint info."""
_cmdline_ = "pie info"
_syntax_ = f"{_cmdline_} BREAKPOINT"
@parse_arguments({"breakpoints": [-1,]}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if args.breakpoints[0] == -1:
# No breakpoint info needed
bps = gef.session.pie_breakpoints.values()
else:
bps = [gef.session.pie_breakpoints[x]
for x in args.breakpoints
if x in gef.session.pie_breakpoints]
lines = ["{:6s} {:6s} {:18s}".format("VNum","Num","Addr")]
lines += [
f"{x.vbp_num:6d} {str(x.bp_num) if x.bp_num else 'N/A':6s} {x.addr:18s}" for x in bps
]
gef_print("\n".join(lines))
return
@register
class PieDeleteCommand(GenericCommand):
"""Delete a PIE breakpoint."""
_cmdline_ = "pie delete"
_syntax_ = f"{_cmdline_} [BREAKPOINT]"
@parse_arguments({"breakpoints": [-1,]}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
global gef
args : argparse.Namespace = kwargs["arguments"]
if args.breakpoints[0] == -1:
# no arg, delete all
to_delete = list(gef.session.pie_breakpoints.values())
self.delete_bp(to_delete)
else:
self.delete_bp([gef.session.pie_breakpoints[x]
for x in args.breakpoints
if x in gef.session.pie_breakpoints])
return
@staticmethod
def delete_bp(breakpoints: List[PieVirtualBreakpoint]) -> None:
global gef
for bp in breakpoints:
# delete current real breakpoints if exists
if bp.bp_num:
gdb.execute(f"delete {bp.bp_num}")
# delete virtual breakpoints
del gef.session.pie_breakpoints[bp.vbp_num]
return
@register
class PieRunCommand(GenericCommand):
"""Run process with PIE breakpoint support."""
_cmdline_ = "pie run"
_syntax_ = _cmdline_
def do_invoke(self, argv: List[str]) -> None:
global gef
fpath = get_filepath()
if not fpath:
warn("No executable to debug, use `file` to load a binary")
return
if not os.access(fpath, os.X_OK):
warn(f"The file '{fpath}' is not executable.")
return
if is_alive():
warn("gdb is already running. Restart process.")
# get base address
gdb.execute("set stop-on-solib-events 1")
hide_context()
gdb.execute(f"run {' '.join(argv)}")
unhide_context()
gdb.execute("set stop-on-solib-events 0")
vmmap = gef.memory.maps
base_address = [x.page_start for x in vmmap if x.path == get_filepath()][0]
info(f"base address {hex(base_address)}")
# modify all breakpoints
for bp_ins in gef.session.pie_breakpoints.values():
bp_ins.instantiate(base_address)
try:
gdb.execute("continue")
except gdb.error as e:
err(e)
gdb.execute("kill")
return
@register
class PieAttachCommand(GenericCommand):
"""Do attach with PIE breakpoint support."""
_cmdline_ = "pie attach"
_syntax_ = f"{_cmdline_} PID"
def do_invoke(self, argv: List[str]) -> None:
try:
gdb.execute(f"attach {' '.join(argv)}", to_string=True)
except gdb.error as e:
err(e)
return
# after attach, we are stopped so that we can
# get base address to modify our breakpoint
vmmap = gef.memory.maps
base_address = [x.page_start for x in vmmap if x.path == get_filepath()][0]
for bp_ins in gef.session.pie_breakpoints.values():
bp_ins.instantiate(base_address)
gdb.execute("context")
return
@register
class PieRemoteCommand(GenericCommand):
"""Attach to a remote connection with PIE breakpoint support."""
_cmdline_ = "pie remote"
_syntax_ = f"{_cmdline_} REMOTE"
def do_invoke(self, argv: List[str]) -> None:
try:
gdb.execute(f"gef-remote {' '.join(argv)}")
except gdb.error as e:
err(e)
return
# after remote attach, we are stopped so that we can
# get base address to modify our breakpoint
vmmap = gef.memory.maps
base_address = [x.page_start for x in vmmap if x.realpath == get_filepath()][0]
for bp_ins in gef.session.pie_breakpoints.values():
bp_ins.instantiate(base_address)
gdb.execute("context")
return
@register
class SmartEvalCommand(GenericCommand):
"""SmartEval: Smart eval (vague approach to mimic WinDBG `?`)."""
_cmdline_ = "$"
_syntax_ = f"{_cmdline_} EXPR\n{_cmdline_} ADDRESS1 ADDRESS2"
_example_ = (f"\n{_cmdline_} $pc+1"
f"\n{_cmdline_} 0x00007ffff7a10000 0x00007ffff7bce000")
def do_invoke(self, argv: List[str]) -> None:
argc = len(argv)
if argc == 1:
self.evaluate(argv)
return
if argc == 2:
self.distance(argv)
return
def evaluate(self, expr: List[str]) -> None:
def show_as_int(i: int) -> None:
off = gef.arch.ptrsize*8
def comp2_x(x: Any) -> str: return f"{(x + (1 << off)) % (1 << off):x}"
def comp2_b(x: Any) -> str: return f"{(x + (1 << off)) % (1 << off):b}"
try:
s_i = comp2_x(res)
s_i = s_i.rjust(len(s_i)+1, "0") if len(s_i)%2 else s_i
gef_print(f"{i:d}")
gef_print("0x" + comp2_x(res))
gef_print("0b" + comp2_b(res))
gef_print(f"{binascii.unhexlify(s_i)}")
gef_print(f"{binascii.unhexlify(s_i)[::-1]}")
except:
pass
return
parsed_expr = []
for xp in expr:
try:
xp = gdb.parse_and_eval(xp)
xp = int(xp)
parsed_expr.append(f"{xp:d}")
except gdb.error:
parsed_expr.append(str(xp))
try:
res = eval(" ".join(parsed_expr))
if isinstance(res, int):
show_as_int(res)
else:
gef_print(f"{res}")
except SyntaxError:
gef_print(" ".join(parsed_expr))
return
def distance(self, args: Tuple[str, str]) -> None:
try:
x = int(args[0], 16) if is_hex(args[0]) else int(args[0])
y = int(args[1], 16) if is_hex(args[1]) else int(args[1])
gef_print(f"{abs(x - y)}")
except ValueError:
warn(f"Distance requires 2 numbers: {self._cmdline_} 0 0xffff")
return
@register
class CanaryCommand(GenericCommand):
"""Shows the canary value of the current process."""
_cmdline_ = "canary"
_syntax_ = _cmdline_
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
self.dont_repeat()
has_canary = Elf(get_filepath()).checksec["Canary"]
if not has_canary:
warn("This binary was not compiled with SSP.")
return
res = gef.session.canary
if not res:
err("Failed to get the canary")
return
canary, location = res
info(f"The canary of process {gef.session.pid} is at {location:#x}, value is {canary:#x}")
return
@register
class ProcessStatusCommand(GenericCommand):
"""Extends the info given by GDB `info proc`, by giving an exhaustive description of the
process status (file descriptors, ancestor, descendants, etc.)."""
_cmdline_ = "process-status"
_syntax_ = _cmdline_
_aliases_ = ["status", ]
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_NONE)
return
@only_if_gdb_running
@only_if_gdb_target_local
def do_invoke(self, argv: List[str]) -> None:
self.show_info_proc()
self.show_ancestor()
self.show_descendants()
self.show_fds()
self.show_connections()
return
def get_state_of(self, pid: int) -> Dict[str, str]:
res = {}
with open(f"/proc/{pid}/status", "r") as f:
file = f.readlines()
for line in file:
key, value = line.split(":", 1)
res[key.strip()] = value.strip()
return res
def get_cmdline_of(self, pid: int) -> str:
with open(f"/proc/{pid}/cmdline", "r") as f:
return f.read().replace("\x00", "\x20").strip()
def get_process_path_of(self, pid: int) -> str:
return os.readlink(f"/proc/{pid}/exe")
def get_children_pids(self, pid: int) -> List[int]:
cmd = [gef.session.constants["ps"], "-o", "pid", "--ppid", f"{pid}", "--noheaders"]
try:
return [int(x) for x in gef_execute_external(cmd, as_list=True)]
except Exception:
return []
def show_info_proc(self) -> None:
info("Process Information")
pid = gef.session.pid
cmdline = self.get_cmdline_of(pid)
gef_print(f"\tPID {RIGHT_ARROW} {pid}",
f"\tExecutable {RIGHT_ARROW} {self.get_process_path_of(pid)}",
f"\tCommand line {RIGHT_ARROW} '{cmdline}'", sep="\n")
return
def show_ancestor(self) -> None:
info("Parent Process Information")
ppid = int(self.get_state_of(gef.session.pid)["PPid"])
state = self.get_state_of(ppid)
cmdline = self.get_cmdline_of(ppid)
gef_print(f"\tParent PID {RIGHT_ARROW} {state['Pid']}",
f"\tCommand line {RIGHT_ARROW} '{cmdline}'", sep="\n")
return
def show_descendants(self) -> None:
info("Children Process Information")
children = self.get_children_pids(gef.session.pid)
if not children:
gef_print("\tNo child process")
return
for child_pid in children:
state = self.get_state_of(child_pid)
pid = state["Pid"]
gef_print(f"\tPID {RIGHT_ARROW} {pid} (Name: '{self.get_process_path_of(pid)}', CmdLine: '{self.get_cmdline_of(pid)}')")
return
def show_fds(self) -> None:
pid = gef.session.pid
path = f"/proc/{pid:d}/fd"
info("File Descriptors:")
items = os.listdir(path)
if not items:
gef_print("\tNo FD opened")
return
for fname in items:
fullpath = os.path.join(path, fname)
if os.path.islink(fullpath):
gef_print(f"\t{fullpath} {RIGHT_ARROW} {os.readlink(fullpath)}")
return
def list_sockets(self, pid: int) -> List[int]:
sockets = []
path = f"/proc/{pid:d}/fd"
items = os.listdir(path)
for fname in items:
fullpath = os.path.join(path, fname)
if os.path.islink(fullpath) and os.readlink(fullpath).startswith("socket:"):
p = os.readlink(fullpath).replace("socket:", "")[1:-1]
sockets.append(int(p))
return sockets
def parse_ip_port(self, addr: str) -> Tuple[str, int]:
ip, port = addr.split(":")
return socket.inet_ntoa(struct.pack("<I", int(ip, 16))), int(port, 16)
def show_connections(self) -> None:
# https://github.com/torvalds/linux/blob/v4.7/include/net/tcp_states.h#L16
tcp_states_str = {
0x01: "TCP_ESTABLISHED",
0x02: "TCP_SYN_SENT",
0x03: "TCP_SYN_RECV",
0x04: "TCP_FIN_WAIT1",
0x05: "TCP_FIN_WAIT2",
0x06: "TCP_TIME_WAIT",
0x07: "TCP_CLOSE",
0x08: "TCP_CLOSE_WAIT",
0x09: "TCP_LAST_ACK",
0x0A: "TCP_LISTEN",
0x0B: "TCP_CLOSING",
0x0C: "TCP_NEW_SYN_RECV",
}
udp_states_str = {
0x07: "UDP_LISTEN",
}
info("Network Connections")
pid = gef.session.pid
sockets = self.list_sockets(pid)
if not sockets:
gef_print("\tNo open connections")
return
entries = dict()
with open(f"/proc/{pid:d}/net/tcp", "r") as tcp:
entries["TCP"] = [x.split() for x in tcp.readlines()[1:]]
with open(f"/proc/{pid:d}/net/udp", "r") as udp:
entries["UDP"] = [x.split() for x in udp.readlines()[1:]]
for proto in entries:
for entry in entries[proto]:
local, remote, state = entry[1:4]
inode = int(entry[9])
if inode in sockets:
local = self.parse_ip_port(local)
remote = self.parse_ip_port(remote)
state = int(state, 16)
state_str = tcp_states_str[state] if proto == "TCP" else udp_states_str[state]
gef_print(f"\t{local[0]}:{local[1]} {RIGHT_ARROW} {remote[0]}:{remote[1]} ({state_str})")
return
@register
class GefThemeCommand(GenericCommand):
"""Customize GEF appearance."""
_cmdline_ = "theme"
_syntax_ = f"{_cmdline_} [KEY [VALUE]]"
def __init__(self) -> None:
super().__init__(self._cmdline_)
self["context_title_line"] = ("gray", "Color of the borders in context window")
self["context_title_message"] = ("cyan", "Color of the title in context window")
self["default_title_line"] = ("gray", "Default color of borders")
self["default_title_message"] = ("cyan", "Default color of title")
self["table_heading"] = ("blue", "Color of the column headings to tables (e.g. vmmap)")
self["old_context"] = ("gray", "Color to use to show things such as code that is not immediately relevant")
self["disassemble_current_instruction"] = ("green", "Color to use to highlight the current $pc when disassembling")
self["dereference_string"] = ("yellow", "Color of dereferenced string")
self["dereference_code"] = ("gray", "Color of dereferenced code")
self["dereference_base_address"] = ("cyan", "Color of dereferenced address")
self["dereference_register_value"] = ("bold blue", "Color of dereferenced register")
self["registers_register_name"] = ("blue", "Color of the register name in the register window")
self["registers_value_changed"] = ("bold red", "Color of the changed register in the register window")
self["address_stack"] = ("pink", "Color to use when a stack address is found")
self["address_heap"] = ("green", "Color to use when a heap address is found")
self["address_code"] = ("red", "Color to use when a code address is found")
self["source_current_line"] = ("green", "Color to use for the current code line in the source window")
return
def do_invoke(self, args: List[str]) -> None:
self.dont_repeat()
argc = len(args)
if argc == 0:
for key in self.settings:
setting = self[key]
value = Color.colorify(setting, setting)
gef_print(f"{key:40s}: {value}")
return
setting_name = args[0]
if not setting_name in self:
err("Invalid key")
return
if argc == 1:
value = self[setting_name]
gef_print(f"{setting_name:40s}: {Color.colorify(value, value)}")
return
colors = [color for color in args[1:] if color in Color.colors]
self[setting_name] = " ".join(colors)
return
class ExternalStructureManager:
class Structure:
def __init__(self, manager: "ExternalStructureManager", mod_path: pathlib.Path, struct_name: str) -> None:
self.manager = manager
self.module_path = mod_path
self.name = struct_name
self.class_type = self.__get_structure_class()
# if the symbol points to a class factory method and not a class
if not hasattr(self.class_type, "_fields_") and callable(self.class_type):
self.class_type = self.class_type(gef)
return
def __str__(self) -> str:
return self.name
def pprint(self) -> None:
res = []
for _name, _type in self.class_type._fields_:
size = ctypes.sizeof(_type)
name = Color.colorify(_name, gef.config["pcustom.structure_name"])
type = Color.colorify(_type.__name__, gef.config["pcustom.structure_type"])
size = Color.colorify(hex(size), gef.config["pcustom.structure_size"])
offset = Color.boldify(f"{getattr(self.class_type, _name).offset:04x}")
res.append(f"{offset} {name:32s} {type:16s} /* size={size} */")
gef_print("\n".join(res))
return
def __get_structure_class(self) -> Type:
"""Returns a tuple of (class, instance) if modname!classname exists"""
fpath = self.module_path
spec = importlib.util.spec_from_file_location(fpath.stem, fpath)
module = importlib.util.module_from_spec(spec)
sys.modules[fpath.stem] = module
spec.loader.exec_module(module)
_class = getattr(module, self.name)
return _class
def apply_at(self, address: int, max_depth: int, depth: int = 0) -> None:
"""Apply (recursively if possible) the structure format to the given address."""
if depth >= max_depth:
warn("maximum recursion level reached")
return
# read the data at the specified address
_structure = self.class_type()
_sizeof_structure = ctypes.sizeof(_structure)
try:
data = gef.memory.read(address, _sizeof_structure)
except gdb.MemoryError:
err(f"{' ' * depth}Cannot read memory {address:#x}")
return
# deserialize the data
length = min(len(data), _sizeof_structure)
ctypes.memmove(ctypes.addressof(_structure), data, length)
# pretty print all the fields (and call recursively if possible)
ptrsize = gef.arch.ptrsize
unpack = u32 if ptrsize == 4 else u64
for field in _structure._fields_:
_name, _type = field
_value = getattr(_structure, _name)
_offset = getattr(self.class_type, _name).offset
if ((ptrsize == 4 and _type is ctypes.c_uint32)
or (ptrsize == 8 and _type is ctypes.c_uint64)
or (ptrsize == ctypes.sizeof(ctypes.c_void_p) and _type is ctypes.c_void_p)):
# try to dereference pointers
_value = RIGHT_ARROW.join(dereference_from(_value))
line = f"{' ' * depth}"
line += f"{address:#x}+{_offset:#04x} {_name} : ".ljust(40)
line += f"{_value} ({_type.__name__})"
parsed_value = self.__get_ctypes_value(_structure, _name, _value)
if parsed_value:
line += f"{RIGHT_ARROW} {parsed_value}"
gef_print(line)
if issubclass(_type, ctypes.Structure):
self.apply_at(address + _offset, max_depth, depth + 1)
elif _type.__name__.startswith("LP_"):
# Pointer to a structure of a different type
__sub_type_name = _type.__name__.lstrip("LP_")
result = self.manager.find(__sub_type_name)
if result:
_, __structure = result
__address = unpack(gef.memory.read(address + _offset, ptrsize))
__structure.apply_at(__address, max_depth, depth + 1)
return
def __get_ctypes_value(self, struct, item, value) -> str:
if not hasattr(struct, "_values_"): return ""
default = ""
for name, values in struct._values_:
if name != item: continue
if callable(values):
return values(value)
try:
for val, desc in values:
if value == val: return desc
if val is None: default = desc
except Exception as e:
err(f"Error parsing '{name}': {e}")
return default
class Module(dict):
def __init__(self, manager: "ExternalStructureManager", path: pathlib.Path) -> None:
self.manager = manager
self.path = path
self.name = path.stem
self.raw = self.__load()
for entry in self:
structure = ExternalStructureManager.Structure(manager, self.path, entry)
self[structure.name] = structure
return
def __load(self) -> ModuleType:
"""Load a custom module, and return it."""
fpath = self.path
spec = importlib.util.spec_from_file_location(fpath.stem, fpath)
module = importlib.util.module_from_spec(spec)
sys.modules[fpath.stem] = module
spec.loader.exec_module(module)
return module
def __str__(self) -> str:
return self.name
def __iter__(self) -> Generator[str, None, None]:
_invalid = {"BigEndianStructure", "LittleEndianStructure", "Structure"}
for x in dir(self.raw):
if x in _invalid: continue
_attr = getattr(self.raw, x)
# if it's a ctypes.Structure class, add it
if inspect.isclass(_attr) and issubclass(_attr, ctypes.Structure):
yield x
continue
# also accept class factory functions
if callable(_attr) and _attr.__module__ == self.name and x.endswith("_t"):
yield x
continue
return
class Modules(dict):
def __init__(self, manager: "ExternalStructureManager") -> None:
self.manager: "ExternalStructureManager" = manager
self.root: pathlib.Path = manager.path
for entry in self.root.iterdir():
if not entry.is_file(): continue
if entry.suffix != ".py": continue
if entry.name == "__init__.py": continue
module = ExternalStructureManager.Module(manager, entry)
self[module.name] = module
return
def __contains__(self, structure_name: str) -> bool:
"""Return True if the structure name is found in any of the modules"""
for module in self.values():
if structure_name in module:
return True
return False
def __init__(self) -> None:
self.clear_caches()
return
def clear_caches(self) -> None:
self._path = None
self._modules = None
return
@property
def modules(self) -> "ExternalStructureManager.Modules":
if not self._modules:
self._modules = ExternalStructureManager.Modules(self)
return self._modules
@property
def path(self) -> pathlib.Path:
if not self._path:
self._path = pathlib.Path(gef.config["pcustom.struct_path"]).expanduser().absolute()
return self._path
@property
def structures(self) -> Generator[Tuple["ExternalStructureManager.Module", "ExternalStructureManager.Structure"], None, None]:
for module in self.modules.values():
for structure in module.values():
yield module, structure
return
@lru_cache()
def find(self, structure_name: str) -> Optional[Tuple["ExternalStructureManager.Module", "ExternalStructureManager.Structure"]]:
"""Return the module and structure for the given structure name; `None` if the structure name was not found."""
for module in self.modules.values():
if structure_name in module:
return module, module[structure_name]
return None
@register
class PCustomCommand(GenericCommand):
"""Dump user defined structure.
This command attempts to reproduce WinDBG awesome `dt` command for GDB and allows
to apply structures (from symbols or custom) directly to an address.
Custom structures can be defined in pure Python using ctypes, and should be stored
in a specific directory, whose path must be stored in the `pcustom.struct_path`
configuration setting."""
_cmdline_ = "pcustom"
_syntax_ = f"{_cmdline_} [list|edit <StructureName>|show <StructureName>]|<StructureName> 0xADDRESS]"
def __init__(self) -> None:
super().__init__(prefix=True)
self["struct_path"] = (str(pathlib.Path(gef.config["gef.tempdir"]) / "structs"), "Path to store/load the structure ctypes files")
self["max_depth"] = (4, "Maximum level of recursion supported")
self["structure_name"] = ("bold blue", "Color of the structure name")
self["structure_type"] = ("bold red", "Color of the attribute type")
self["structure_size"] = ("green", "Color of the attribute size")
return
@parse_arguments({"type": "", "address": ""}, {})
def do_invoke(self, *_: Any, **kwargs: Dict[str, Any]) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not args.type:
gdb.execute("pcustom list")
return
_, structname = self.explode_type(args.type)
if not args.address:
gdb.execute(f"pcustom show {structname}")
return
if not is_alive():
err("Session is not active")
return
manager = ExternalStructureManager()
address = parse_address(args.address)
result = manager.find(structname)
if not result:
err(f"No structure named '{structname}' found")
return
_, structure = result
structure.apply_at(address, self["max_depth"])
return
def explode_type(self, arg: str) -> Tuple[str, str]:
modname, structname = arg.split(":", 1) if ":" in arg else (arg, arg)
structname = structname.split(".", 1)[0] if "." in structname else structname
return modname, structname
@register
class PCustomListCommand(PCustomCommand):
"""PCustom: list available structures"""
_cmdline_ = "pcustom list"
_syntax_ = f"{_cmdline_}"
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, _: List) -> None:
"""Dump the list of all the structures and their respective."""
manager = ExternalStructureManager()
info(f"Listing custom structures from '{manager.path}'")
struct_color = gef.config["pcustom.structure_type"]
filename_color = gef.config["pcustom.structure_name"]
for module in manager.modules.values():
__modules = ", ".join([Color.colorify(structure_name, struct_color) for structure_name in module.values()])
__filename = Color.colorify(str(module.path), filename_color)
gef_print(f"{RIGHT_ARROW} {__filename} ({__modules})")
return
@register
class PCustomShowCommand(PCustomCommand):
"""PCustom: show the content of a given structure"""
_cmdline_ = "pcustom show"
_syntax_ = f"{_cmdline_} StructureName"
__aliases__ = ["pcustom create", "pcustom update"]
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, argv: List[str]) -> None:
if len(argv) == 0:
self.usage()
return
_, structname = self.explode_type(argv[0])
manager = ExternalStructureManager()
result = manager.find(structname)
if result:
_, structure = result
structure.pprint()
else:
err(f"No structure named '{structname}' found")
return
@register
class PCustomEditCommand(PCustomCommand):
"""PCustom: edit the content of a given structure"""
_cmdline_ = "pcustom edit"
_syntax_ = f"{_cmdline_} StructureName"
__aliases__ = ["pcustom create", "pcustom new", "pcustom update"]
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, argv: List[str]) -> None:
if len(argv) == 0:
self.usage()
return
modname, structname = self.explode_type(argv[0])
self.__create_or_edit_structure(modname, structname)
return
def __create_or_edit_structure(self, mod_name: str, struct_name: str) -> int:
path = pathlib.Path(gef.config["pcustom.struct_path"]).expanduser() / f"{mod_name}.py"
if path.is_file():
info(f"Editing '{path}'")
else:
ok(f"Creating '{path}' from template")
self.__create_template(struct_name, path)
cmd = (os.getenv("EDITOR") or "nano").split()
cmd.append(str(path.absolute()))
return subprocess.call(cmd)
def __create_template(self, structname: str, fpath: pathlib.Path) -> None:
template = f"""from ctypes import *
class {structname}(Structure):
_fields_ = []
_values_ = []
"""
with fpath.open("w") as f:
f.write(template)
return
@register
class ChangeFdCommand(GenericCommand):
"""ChangeFdCommand: redirect file descriptor during runtime."""
_cmdline_ = "hijack-fd"
_syntax_ = f"{_cmdline_} FD_NUM NEW_OUTPUT"
_example_ = f"{_cmdline_} 2 /tmp/stderr_output.txt"
@only_if_gdb_running
@only_if_gdb_target_local
def do_invoke(self, argv: List[str]) -> None:
if len(argv) != 2:
self.usage()
return
if not os.access(f"/proc/{gef.session.pid:d}/fd/{argv[0]}", os.R_OK):
self.usage()
return
old_fd = int(argv[0])
new_output = argv[1]
if ":" in new_output:
address = socket.gethostbyname(new_output.split(":")[0])
port = int(new_output.split(":")[1])
AF_INET = 2
SOCK_STREAM = 1
res = gdb.execute(f"""call (int)socket({AF_INET}, {SOCK_STREAM}, 0)""", to_string=True)
new_fd = self.get_fd_from_result(res)
# fill in memory with sockaddr_in struct contents
# we will do this in the stack, since connect() wants a pointer to a struct
vmmap = gef.memory.maps
stack_addr = [entry.page_start for entry in vmmap if entry.path == "[stack]"][0]
original_contents = gef.memory.read(stack_addr, 8)
gef.memory.write(stack_addr, b"\x02\x00", 2)
gef.memory.write(stack_addr + 0x2, struct.pack("<H", socket.htons(port)), 2)
gef.memory.write(stack_addr + 0x4, socket.inet_aton(address), 4)
info(f"Trying to connect to {new_output}")
res = gdb.execute(f"""call (int)connect({new_fd}, {stack_addr}, {16})""", to_string=True)
# recover stack state
gef.memory.write(stack_addr, original_contents, 8)
res = self.get_fd_from_result(res)
if res == -1:
err(f"Failed to connect to {address}:{port}")
return
info(f"Connected to {new_output}")
else:
res = gdb.execute(f"""call (int)open("{new_output}", 66, 0666)""", to_string=True)
new_fd = self.get_fd_from_result(res)
info(f"Opened '{new_output}' as fd #{new_fd:d}")
gdb.execute(f"""call (int)dup2({new_fd:d}, {old_fd:d})""", to_string=True)
info(f"Duplicated fd #{new_fd:d}{RIGHT_ARROW}#{old_fd:d}")
gdb.execute(f"""call (int)close({new_fd:d})""", to_string=True)
info(f"Closed extra fd #{new_fd:d}")
ok("Success")
return
def get_fd_from_result(self, res: str) -> int:
# Output example: $1 = 3
res = gdb.execute(f"""p/d {int(res.split()[2], 0)}""", to_string=True)
return int(res.split()[2], 0)
@register
class ScanSectionCommand(GenericCommand):
"""Search for addresses that are located in a memory mapping (haystack) that belonging
to another (needle)."""
_cmdline_ = "scan"
_syntax_ = f"{_cmdline_} HAYSTACK NEEDLE"
_aliases_ = ["lookup",]
_example_ = f"\n{_cmdline_} stack libc"
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if len(argv) != 2:
self.usage()
return
haystack = argv[0]
needle = argv[1]
info(f"Searching for addresses in '{Color.yellowify(haystack)}' "
f"that point to '{Color.yellowify(needle)}'")
if haystack == "binary":
haystack = get_filepath()
if needle == "binary":
needle = get_filepath()
needle_sections = []
haystack_sections = []
if "0x" in haystack:
start, end = parse_string_range(haystack)
haystack_sections.append((start, end, ""))
if "0x" in needle:
start, end = parse_string_range(needle)
needle_sections.append((start, end))
for sect in gef.memory.maps:
if haystack in sect.path:
haystack_sections.append((sect.page_start, sect.page_end, os.path.basename(sect.path)))
if needle in sect.path:
needle_sections.append((sect.page_start, sect.page_end))
step = gef.arch.ptrsize
unpack = u32 if step == 4 else u64
for hstart, hend, hname in haystack_sections:
try:
mem = gef.memory.read(hstart, hend - hstart)
except gdb.MemoryError:
continue
for i in range(0, len(mem), step):
target = unpack(mem[i:i+step])
for nstart, nend in needle_sections:
if target >= nstart and target < nend:
deref = DereferenceCommand.pprint_dereferenced(hstart, int(i / step))
if hname != "":
name = Color.colorify(hname, "yellow")
gef_print(f"{name}: {deref}")
else:
gef_print(f" {deref}")
return
@register
class SearchPatternCommand(GenericCommand):
"""SearchPatternCommand: search a pattern in memory. If given an hex value (starting with 0x)
the command will also try to look for upwards cross-references to this address."""
_cmdline_ = "search-pattern"
_syntax_ = f"{_cmdline_} PATTERN [little|big] [section]"
_aliases_ = ["grep", "xref"]
_example_ = [f"{_cmdline_} AAAAAAAA",
f"{_cmdline_} 0x555555554000 little stack",
f"{_cmdline_} AAAA 0x600000-0x601000",
f"{_cmdline_} --regex 0x401000 0x401500 ([\\\\x20-\\\\x7E]{{2,}})(?=\\\\x00) <-- It matchs null-end-printable(from x20-x7e) C strings (min size 2 bytes)"]
def __init__(self) -> None:
super().__init__()
self["max_size_preview"] = (10, "max size preview of bytes")
self["nr_pages_chunk"] = (0x400, "number of pages readed for each memory read chunk")
return
def print_section(self, section: Section) -> None:
title = "In "
if section.path:
title += f"'{Color.blueify(section.path)}'"
title += f"({section.page_start:#x}-{section.page_end:#x})"
title += f", permission={section.permission}"
ok(title)
return
def print_loc(self, loc: Tuple[int, int, str]) -> None:
gef_print(f""" {loc[0]:#x} - {loc[1]:#x} {RIGHT_ARROW} "{Color.pinkify(loc[2])}" """)
return
def search_pattern_by_address(self, pattern: str, start_address: int, end_address: int) -> List[Tuple[int, int, Optional[str]]]:
"""Search a pattern within a range defined by arguments."""
_pattern = gef_pybytes(pattern)
step = self["nr_pages_chunk"] * gef.session.pagesize
locations = []
for chunk_addr in range(start_address, end_address, step):
if chunk_addr + step > end_address:
chunk_size = end_address - chunk_addr
else:
chunk_size = step
try:
mem = gef.memory.read(chunk_addr, chunk_size)
except gdb.MemoryError as e:
return []
for match in re.finditer(_pattern, mem):
start = chunk_addr + match.start()
if is_ascii_string(start):
ustr = gef.memory.read_ascii_string(start) or ""
end = start + len(ustr)
else:
ustr = gef_pystring(_pattern) + "[...]"
end = start + len(_pattern)
locations.append((start, end, ustr))
del mem
return locations
def search_binpattern_by_address(self, binpattern: bytes, start_address: int, end_address: int) -> List[Tuple[int, int, Optional[str]]]:
"""Search a binary pattern within a range defined by arguments."""
step = self["nr_pages_chunk"] * gef.session.pagesize
locations = []
for chunk_addr in range(start_address, end_address, step):
if chunk_addr + step > end_address:
chunk_size = end_address - chunk_addr
else:
chunk_size = step
try:
mem = gef.memory.read(chunk_addr, chunk_size)
except gdb.MemoryError as e:
return []
preview_size = self["max_size_preview"]
for match in re.finditer(binpattern, mem):
start = chunk_addr + match.start()
preview = str(mem[slice(*match.span())][0:preview_size]) + "..."
size_match = match.span()[1] - match.span()[0]
if size_match > 0:
size_match -= 1
end = start + size_match
locations.append((start, end, preview))
del mem
return locations
def search_pattern(self, pattern: str, section_name: str) -> None:
"""Search a pattern within the whole userland memory."""
for section in gef.memory.maps:
if not section.permission & Permission.READ: continue
if section.path == "[vvar]": continue
if not section_name in section.path: continue
start = section.page_start
end = section.page_end - 1
old_section = None
for loc in self.search_pattern_by_address(pattern, start, end):
addr_loc_start = lookup_address(loc[0])
if addr_loc_start and addr_loc_start.section:
if old_section != addr_loc_start.section:
self.print_section(addr_loc_start.section)
old_section = addr_loc_start.section
self.print_loc(loc)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
argc = len(argv)
if argc < 1:
self.usage()
return
if argc > 3 and argv[0].startswith("--regex"):
pattern = ' '.join(argv[3:])
pattern = ast.literal_eval("b'" + pattern + "'")
addr_start = parse_address(argv[1])
addr_end = parse_address(argv[2])
for loc in self.search_binpattern_by_address(pattern, addr_start, addr_end):
self.print_loc(loc)
return
pattern = argv[0]
endian = gef.arch.endianness
if argc >= 2:
if argv[1].lower() == "big": endian = Endianness.BIG_ENDIAN
elif argv[1].lower() == "little": endian = Endianness.LITTLE_ENDIAN
if is_hex(pattern):
if endian == Endianness.BIG_ENDIAN:
pattern = "".join(["\\x" + pattern[i:i + 2] for i in range(2, len(pattern), 2)])
else:
pattern = "".join(["\\x" + pattern[i:i + 2] for i in range(len(pattern) - 2, 0, -2)])
if argc == 3:
info(f"Searching '{Color.yellowify(pattern)}' in {argv[2]}")
if "0x" in argv[2]:
start, end = parse_string_range(argv[2])
loc = lookup_address(start)
if loc.valid:
self.print_section(loc.section)
for loc in self.search_pattern_by_address(pattern, start, end):
self.print_loc(loc)
else:
section_name = argv[2]
if section_name == "binary":
section_name = get_filepath() or ""
self.search_pattern(pattern, section_name)
else:
info(f"Searching '{Color.yellowify(pattern)}' in memory")
self.search_pattern(pattern, "")
return
@register
class FlagsCommand(GenericCommand):
"""Edit flags in a human friendly way."""
_cmdline_ = "edit-flags"
_syntax_ = f"{_cmdline_} [(+|-|~)FLAGNAME ...]"
_aliases_ = ["flags",]
_example_ = (f"\n{_cmdline_}"
f"\n{_cmdline_} +zero # sets ZERO flag")
def do_invoke(self, argv: List[str]) -> None:
if not gef.arch.flag_register:
warn(f"The architecture {gef.arch.arch}:{gef.arch.mode} doesn't have flag register.")
return
for flag in argv:
if len(flag) < 2:
continue
action = flag[0]
name = flag[1:].lower()
if action not in ("+", "-", "~"):
err(f"Invalid action for flag '{flag}'")
continue
if name not in gef.arch.flags_table.values():
err(f"Invalid flag name '{flag[1:]}'")
continue
for off in gef.arch.flags_table:
if gef.arch.flags_table[off] == name:
old_flag = gef.arch.register(gef.arch.flag_register)
if action == "+":
new_flags = old_flag | (1 << off)
elif action == "-":
new_flags = old_flag & ~(1 << off)
else:
new_flags = old_flag ^ (1 << off)
gdb.execute(f"set ({gef.arch.flag_register}) = {new_flags:#x}")
gef_print(gef.arch.flag_register_to_human())
return
@register
class RemoteCommand(GenericCommand):
"""GDB `target remote` command on steroids. This command will use the remote procfs to create
a local copy of the execution environment, including the target binary and its libraries
in the local temporary directory (the value by default is in `gef.config.tempdir`). Additionally, it
will fetch all the /proc/PID/maps and loads all its information. If procfs is not available remotely, the command
will likely fail. You can however still use the limited command provided by GDB `target remote`."""
_cmdline_ = "gef-remote"
_syntax_ = f"{_cmdline_} [OPTIONS] TARGET"
_example_ = [f"{_cmdline_} localhost 1234",
f"{_cmdline_} --pid 6789 localhost 1234",
f"{_cmdline_} --qemu-user --qemu-binary /bin/debugme localhost 4444 "]
def __init__(self) -> None:
super().__init__(prefix=False)
return
@parse_arguments({"host": "", "port": 0}, {"--pid": -1, "--qemu-user": True, "--qemu-binary": ""})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
if gef.session.remote is not None:
err("You already are in remote session. Close it first before opening a new one...")
return
# argument check
args : argparse.Namespace = kwargs["arguments"]
if not args.host or not args.port:
err("Missing parameters")
return
# qemu-user support
qemu_binary: Optional[pathlib.Path] = None
try:
if args.qemu_user:
qemu_binary = pathlib.Path(args.qemu_binary).expanduser().absolute() if args.qemu_binary else gef.session.file
if not qemu_binary or not qemu_binary.exists():
raise FileNotFoundError(f"{qemu_binary} does not exist")
except Exception as e:
err(f"Failed to initialize qemu-user mode, reason: {str(e)}")
return
# try to establish the remote session, throw on error
# Set `.remote_initializing` to True here - `GefRemoteSessionManager` invokes code which
# calls `is_remote_debug` which checks if `remote_initializing` is True or `.remote` is None
# This prevents some spurious errors being thrown during startup
gef.session.remote_initializing = True
gef.session.remote = GefRemoteSessionManager(args.host, args.port, args.pid, qemu_binary)
gef.session.remote_initializing = False
reset_all_caches()
gdb.execute("context")
return
@register
class NopCommand(GenericCommand):
"""Patch the instruction(s) pointed by parameters with NOP. Note: this command is architecture
aware."""
_cmdline_ = "nop"
_syntax_ = ("{_cmdline_} [LOCATION] [--nb NUM_BYTES]"
"\n\tLOCATION\taddress/symbol to patch"
"\t--nb NUM_BYTES\tInstead of writing one instruction, patch the specified number of bytes")
_example_ = f"{_cmdline_} $pc"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
@parse_arguments({"address": "$pc"}, {"--nb": 0, })
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
address = parse_address(args.address)
nop = gef.arch.nop_insn
number_of_bytes = args.nb or 1
insn = gef_get_instruction_at(address)
if insn.size() != number_of_bytes:
warn(f"Patching {number_of_bytes} bytes at {address:#x} might result in corruption")
nops = bytearray(nop * number_of_bytes)
end_address = Address(value=address + len(nops))
if not end_address.valid:
err(f"Cannot patch instruction at {address:#x}: reaching unmapped area")
return
ok(f"Patching {len(nops)} bytes from {address:#x}")
gef.memory.write(address, nops, len(nops))
return
@register
class StubCommand(GenericCommand):
"""Stub out the specified function. This function is useful when needing to skip one
function to be called and disrupt your runtime flow (ex. fork)."""
_cmdline_ = "stub"
_syntax_ = (f"{_cmdline_} [--retval RETVAL] [address]"
"\taddress\taddress/symbol to stub out"
"\t--retval RETVAL\tSet the return value")
_example_ = f"{_cmdline_} --retval 0 fork"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
@parse_arguments({"address": ""}, {("-r", "--retval"): 0})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
loc = args.address if args.address else f"*{gef.arch.pc:#x}"
StubBreakpoint(loc, args.retval)
return
@register
class GlibcHeapCommand(GenericCommand):
"""Base command to get information about the Glibc heap structure."""
_cmdline_ = "heap"
_syntax_ = f"{_cmdline_} (chunk|chunks|bins|arenas|set-arena)"
def __init__(self) -> None:
super().__init__(prefix=True)
return
@only_if_gdb_running
def do_invoke(self, _: List[str]) -> None:
self.usage()
return
@register
class GlibcHeapSetArenaCommand(GenericCommand):
"""Set the address of the main_arena or the currently selected arena."""
_cmdline_ = "heap set-arena"
_syntax_ = f"{_cmdline_} [address|&symbol]"
_example_ = f"{_cmdline_} 0x001337001337"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
@parse_arguments({"addr": ""}, {"--reset": True})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
global gef
args: argparse.Namespace = kwargs["arguments"]
if args.reset:
gef.heap.reset_caches()
return
if not args.addr:
ok(f"Current arena set to: '{gef.heap.selected_arena}'")
return
try:
new_arena_address = parse_address(args.addr)
except gdb.error:
err("Invalid symbol for arena")
return
new_arena = GlibcArena( f"*{new_arena_address:#x}")
if new_arena in gef.heap.arenas:
# if entered arena is in arena list then just select it
gef.heap.selected_arena = new_arena
else:
# otherwise set the main arena to the entered arena
gef.heap.main_arena = new_arena
return
@register
class GlibcHeapArenaCommand(GenericCommand):
"""Display information on a heap chunk."""
_cmdline_ = "heap arenas"
_syntax_ = _cmdline_
@only_if_gdb_running
def do_invoke(self, _: List[str]) -> None:
for arena in gef.heap.arenas:
gef_print(str(arena))
return
@register
class GlibcHeapChunkCommand(GenericCommand):
"""Display information on a heap chunk.
See https://github.com/sploitfun/lsploits/blob/master/glibc/malloc/malloc.c#L1123."""
_cmdline_ = "heap chunk"
_syntax_ = f"{_cmdline_} [-h] [--allow-unaligned] [--number] address"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({"address": ""}, {"--allow-unaligned": True, "--number": 1})
@only_if_gdb_running
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not args.address:
err("Missing chunk address")
self.usage()
return
addr = parse_address(args.address)
current_chunk = GlibcChunk(addr, allow_unaligned=args.allow_unaligned)
if args.number > 1:
for _i in range(args.number):
if current_chunk.size == 0:
break
gef_print(str(current_chunk))
next_chunk_addr = current_chunk.get_next_chunk_addr()
if not Address(value=next_chunk_addr).valid:
break
next_chunk = current_chunk.get_next_chunk()
if next_chunk is None:
break
current_chunk = next_chunk
else:
gef_print(current_chunk.psprint())
return
@register
class GlibcHeapChunksCommand(GenericCommand):
"""Display all heap chunks for the current arena. As an optional argument
the base address of a different arena can be passed"""
_cmdline_ = "heap chunks"
_syntax_ = f"{_cmdline_} [-h] [--all] [--allow-unaligned] [arena_address]"
_example_ = (f"\n{_cmdline_}"
f"\n{_cmdline_} 0x555555775000")
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
self["peek_nb_byte"] = (16, "Hexdump N first byte(s) inside the chunk data (0 to disable)")
return
@parse_arguments({"arena_address": ""}, {("--all", "-a"): True, "--allow-unaligned": True})
@only_if_gdb_running
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args = kwargs["arguments"]
if args.all or not args.arena_address:
for arena in gef.heap.arenas:
self.dump_chunks_arena(arena, print_arena=args.all, allow_unaligned=args.allow_unaligned)
if not args.all:
return
try:
arena_addr = parse_address(args.arena_address)
arena = GlibcArena(f"*{arena_addr:#x}")
self.dump_chunks_arena(arena, allow_unaligned=args.allow_unaligned)
except gdb.error:
err("Invalid arena")
return
def dump_chunks_arena(self, arena: GlibcArena, print_arena: bool = False, allow_unaligned: bool = False) -> None:
heap_addr = arena.heap_addr(allow_unaligned=allow_unaligned)
if heap_addr is None:
err("Could not find heap for arena")
return
if print_arena:
gef_print(str(arena))
if arena.is_main_arena():
heap_end = arena.top + GlibcChunk(arena.top, from_base=True).size
self.dump_chunks_heap(heap_addr, heap_end, arena, allow_unaligned=allow_unaligned)
else:
heap_info_structs = arena.get_heap_info_list() or []
for heap_info in heap_info_structs:
if not self.dump_chunks_heap(heap_info.heap_start, heap_info.heap_end, arena, allow_unaligned=allow_unaligned):
break
return
def dump_chunks_heap(self, start: int, end: int, arena: GlibcArena, allow_unaligned: bool = False) -> bool:
nb = self["peek_nb_byte"]
chunk_iterator = GlibcChunk(start, from_base=True, allow_unaligned=allow_unaligned)
for chunk in chunk_iterator:
if chunk.base_address == arena.top:
gef_print(
f"{chunk!s} {LEFT_ARROW} {Color.greenify('top chunk')}")
break
if chunk.base_address > end:
err("Corrupted heap, cannot continue.")
return False
line = str(chunk)
if nb:
line += f"\n [{hexdump(gef.memory.read(chunk.data_address, nb), nb, base=chunk.data_address)}]"
gef_print(line)
return True
@register
class GlibcHeapBinsCommand(GenericCommand):
"""Display information on the bins on an arena (default: main_arena).
See https://github.com/sploitfun/lsploits/blob/master/glibc/malloc/malloc.c#L1123."""
_bin_types_ = ("tcache", "fast", "unsorted", "small", "large")
_cmdline_ = "heap bins"
_syntax_ = f"{_cmdline_} [{'|'.join(_bin_types_)}]"
def __init__(self) -> None:
super().__init__(prefix=True, complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if not argv:
for bin_t in self._bin_types_:
gdb.execute(f"heap bins {bin_t}")
return
bin_t = argv[0]
if bin_t not in self._bin_types_:
self.usage()
return
gdb.execute(f"heap bins {bin_t}")
return
@staticmethod
def pprint_bin(arena_addr: str, index: int, _type: str = "") -> int:
arena = GlibcArena(arena_addr)
fd, bk = arena.bin(index)
if (fd, bk) == (0x00, 0x00):
warn("Invalid backward and forward bin pointers(fw==bk==NULL)")
return -1
if _type == "tcache":
chunkClass = GlibcTcacheChunk
elif _type == "fast":
chunkClass = GlibcFastChunk
else:
chunkClass = GlibcChunk
nb_chunk = 0
head = chunkClass(bk, from_base=True).fd
if fd == head:
return nb_chunk
ok(f"{_type}bins[{index:d}]: fw={fd:#x}, bk={bk:#x}")
m = []
while fd != head:
chunk = chunkClass(fd, from_base=True)
m.append(f"{RIGHT_ARROW} {chunk!s}")
fd = chunk.fd
nb_chunk += 1
if m:
gef_print(" ".join(m))
return nb_chunk
@register
class GlibcHeapTcachebinsCommand(GenericCommand):
"""Display information on the Tcachebins on an arena (default: main_arena).
See https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=d5c3fafc4307c9b7a4c7d5cb381fcdbfad340bcc."""
_cmdline_ = "heap bins tcache"
_syntax_ = f"{_cmdline_} [all] [thread_ids...]"
TCACHE_MAX_BINS = 0x40
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
# Determine if we are using libc with tcache built in (2.26+)
if gef.libc.version and gef.libc.version < (2, 26):
info("No Tcache in this version of libc")
return
current_thread = gdb.selected_thread()
if current_thread is None:
err("Couldn't find current thread")
return
# As a nicety, we want to display threads in ascending order by gdb number
threads = sorted(gdb.selected_inferior().threads(), key=lambda t: t.num)
if argv:
if "all" in argv:
tids = [t.num for t in threads]
else:
tids = self.check_thread_ids(argv)
else:
tids = [current_thread.num]
for thread in threads:
if thread.num not in tids:
continue
thread.switch()
tcache_addr = self.find_tcache()
if tcache_addr == 0:
info(f"Uninitialized tcache for thread {thread.num:d}")
continue
gef_print(titlify(f"Tcachebins for thread {thread.num:d}"))
tcache_empty = True
for i in range(self.TCACHE_MAX_BINS):
chunk, count = self.tcachebin(tcache_addr, i)
chunks = set()
msg = []
chunk_size = 0
# Only print the entry if there are valid chunks. Don't trust count
while True:
if chunk is None:
break
try:
msg.append(f"{LEFT_ARROW} {chunk!s} ")
if not chunk_size:
chunk_size = chunk.usable_size
if chunk.data_address in chunks:
msg.append(f"{RIGHT_ARROW} [loop detected]")
break
chunks.add(chunk.data_address)
next_chunk = chunk.fd
if next_chunk == 0:
break
chunk = GlibcTcacheChunk(next_chunk)
except gdb.MemoryError:
msg.append(f"{LEFT_ARROW} [Corrupted chunk at {chunk.data_address:#x}]")
break
if msg:
tcache_empty = False
tidx = gef.heap.csize2tidx(chunk_size)
size = gef.heap.tidx2size(tidx)
count = len(chunks)
gef_print(f"Tcachebins[idx={tidx:d}, size={size:#x}, count={count}]", end="")
gef_print("".join(msg))
if tcache_empty:
gef_print("All tcachebins are empty")
current_thread.switch()
return
@staticmethod
def find_tcache() -> int:
"""Return the location of the current thread's tcache."""
try:
# For multithreaded binaries, the tcache symbol (in thread local
# storage) will give us the correct address.
tcache_addr = parse_address("(void *) tcache")
except gdb.error:
# In binaries not linked with pthread (and therefore there is only
# one thread), we can't use the tcache symbol, but we can guess the
# correct address because the tcache is consistently the first
# allocation in the main arena.
heap_base = gef.heap.base_address
if heap_base is None:
err("No heap section")
return 0x0
tcache_addr = heap_base + 0x10
return tcache_addr
@staticmethod
def check_thread_ids(tids: List[int]) -> List[int]:
"""Check the validity, dedup, and return all valid tids."""
existing_tids = [t.num for t in gdb.selected_inferior().threads()]
valid_tids = set()
for tid in tids:
try:
tid = int(tid)
except ValueError:
err(f"Invalid thread id {tid:d}")
continue
if tid in existing_tids:
valid_tids.add(tid)
else:
err(f"Unknown thread {tid}")
return list(valid_tids)
@staticmethod
def tcachebin(tcache_base: int, i: int) -> Tuple[Optional[GlibcTcacheChunk], int]:
"""Return the head chunk in tcache[i] and the number of chunks in the bin."""
if i >= GlibcHeapTcachebinsCommand.TCACHE_MAX_BINS:
err("Incorrect index value, index value must be between 0 and {}-1, given {}".format(GlibcHeapTcachebinsCommand.TCACHE_MAX_BINS, i))
return None, 0
tcache_chunk = GlibcTcacheChunk(tcache_base)
# Glibc changed the size of the tcache in version 2.30; this fix has
# been backported inconsistently between distributions. We detect the
# difference by checking the size of the allocated chunk for the
# tcache.
# Minimum usable size of allocated tcache chunk = ?
# For new tcache:
# TCACHE_MAX_BINS * _2_ + TCACHE_MAX_BINS * ptrsize
# For old tcache:
# TCACHE_MAX_BINS * _1_ + TCACHE_MAX_BINS * ptrsize
new_tcache_min_size = (
GlibcHeapTcachebinsCommand.TCACHE_MAX_BINS * 2 +
GlibcHeapTcachebinsCommand.TCACHE_MAX_BINS * gef.arch.ptrsize)
if tcache_chunk.usable_size < new_tcache_min_size:
tcache_count_size = 1
count = ord(gef.memory.read(tcache_base + tcache_count_size*i, 1))
else:
tcache_count_size = 2
count = u16(gef.memory.read(tcache_base + tcache_count_size*i, 2))
chunk = dereference(tcache_base + tcache_count_size*GlibcHeapTcachebinsCommand.TCACHE_MAX_BINS + i*gef.arch.ptrsize)
chunk = GlibcTcacheChunk(int(chunk)) if chunk else None
return chunk, count
@register
class GlibcHeapFastbinsYCommand(GenericCommand):
"""Display information on the fastbinsY on an arena (default: main_arena).
See https://github.com/sploitfun/lsploits/blob/master/glibc/malloc/malloc.c#L1123."""
_cmdline_ = "heap bins fast"
_syntax_ = f"{_cmdline_} [ARENA_ADDRESS]"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({"arena_address": ""}, {})
@only_if_gdb_running
def do_invoke(self, *_: Any, **kwargs: Any) -> None:
def fastbin_index(sz: int) -> int:
return (sz >> 4) - 2 if SIZE_SZ == 8 else (sz >> 3) - 2
args : argparse.Namespace = kwargs["arguments"]
if not gef.heap.main_arena:
err("Heap not initialized")
return
SIZE_SZ = gef.arch.ptrsize
MAX_FAST_SIZE = 80 * SIZE_SZ // 4
NFASTBINS = fastbin_index(MAX_FAST_SIZE) - 1
arena = GlibcArena(f"*{args.arena_address}") if args.arena_address else gef.heap.selected_arena
if arena is None:
err("Invalid Glibc arena")
return
gef_print(titlify(f"Fastbins for arena at {arena.addr:#x}"))
for i in range(NFASTBINS):
gef_print(f"Fastbins[idx={i:d}, size={(i+2)*SIZE_SZ*2:#x}] ", end="")
chunk = arena.fastbin(i)
chunks = set()
while True:
if chunk is None:
gef_print("0x00", end="")
break
try:
gef_print(f"{LEFT_ARROW} {chunk!s} ", end="")
if chunk.data_address in chunks:
gef_print(f"{RIGHT_ARROW} [loop detected]", end="")
break
if fastbin_index(chunk.size) != i:
gef_print("[incorrect fastbin_index] ", end="")
chunks.add(chunk.data_address)
next_chunk = chunk.fd
if next_chunk == 0:
break
chunk = GlibcFastChunk(next_chunk, from_base=True)
except gdb.MemoryError:
gef_print(f"{LEFT_ARROW} [Corrupted chunk at {chunk.data_address:#x}]", end="")
break
gef_print()
return
@register
class GlibcHeapUnsortedBinsCommand(GenericCommand):
"""Display information on the Unsorted Bins of an arena (default: main_arena).
See: https://github.com/sploitfun/lsploits/blob/master/glibc/malloc/malloc.c#L1689."""
_cmdline_ = "heap bins unsorted"
_syntax_ = f"{_cmdline_} [ARENA_ADDRESS]"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({"arena_address": ""}, {})
@only_if_gdb_running
def do_invoke(self, *_: Any, **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if gef.heap.main_arena is None:
err("Heap not initialized")
return
arena_addr = args.arena_address if args.arena_address else f"{gef.heap.selected_arena.addr:#x}"
gef_print(titlify(f"Unsorted Bin for arena at {arena_addr}"))
nb_chunk = GlibcHeapBinsCommand.pprint_bin(f"*{arena_addr}", 0, "unsorted_")
if nb_chunk >= 0:
info(f"Found {nb_chunk:d} chunks in unsorted bin.")
return
@register
class GlibcHeapSmallBinsCommand(GenericCommand):
"""Convenience command for viewing small bins."""
_cmdline_ = "heap bins small"
_syntax_ = f"{_cmdline_} [ARENA_ADDRESS]"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({"arena_address": ""}, {})
@only_if_gdb_running
def do_invoke(self, *_: Any, **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not gef.heap.main_arena:
err("Heap not initialized")
return
arena_address = args.arena_address or f"{gef.heap.selected_arena.address:#x}"
gef_print(titlify(f"Small Bins for arena at {arena_address}"))
bins = {}
for i in range(1, 63):
nb_chunk = GlibcHeapBinsCommand.pprint_bin(f"*{arena_address}", i, "small_")
if nb_chunk < 0:
break
if nb_chunk > 0:
bins[i] = nb_chunk
info(f"Found {sum(bins.values()):d} chunks in {len(bins):d} small non-empty bins.")
return
@register
class GlibcHeapLargeBinsCommand(GenericCommand):
"""Convenience command for viewing large bins."""
_cmdline_ = "heap bins large"
_syntax_ = f"{_cmdline_} [ARENA_ADDRESS]"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({"arena_address": ""}, {})
@only_if_gdb_running
def do_invoke(self, *_: Any, **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if gef.heap.main_arena is None:
err("Heap not initialized")
return
arena_addr = args.arena_address if args.arena_address else f"{gef.heap.selected_arena.addr:#x}"
gef_print(titlify(f"Large Bins for arena at {arena_addr}"))
bins = {}
for i in range(63, 126):
nb_chunk = GlibcHeapBinsCommand.pprint_bin(f"*{arena_addr}", i, "large_")
if nb_chunk < 0:
break
if nb_chunk > 0:
bins[i] = nb_chunk
info(f"Found {sum(bins.values()):d} chunks in {len(bins):d} large non-empty bins.")
return
@register
class SolveKernelSymbolCommand(GenericCommand):
"""Solve kernel symbols from kallsyms table."""
_cmdline_ = "ksymaddr"
_syntax_ = f"{_cmdline_} SymbolToSearch"
_example_ = f"{_cmdline_} prepare_creds"
@parse_arguments({"symbol": ""}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
def hex_to_int(num):
try:
return int(num, 16)
except ValueError:
return 0
args : argparse.Namespace = kwargs["arguments"]
if not args.symbol:
self.usage()
return
sym = args.symbol
with open("/proc/kallsyms", "r") as f:
syms = [line.strip().split(" ", 2) for line in f]
matches = [(hex_to_int(addr), sym_t, " ".join(name.split())) for addr, sym_t, name in syms if sym in name]
for addr, sym_t, name in matches:
if sym == name.split()[0]:
ok(f"Found matching symbol for '{name}' at {addr:#x} (type={sym_t})")
else:
warn(f"Found partial match for '{sym}' at {addr:#x} (type={sym_t}): {name}")
if not matches:
err(f"No match for '{sym}'")
elif matches[0][0] == 0:
err("Check that you have the correct permissions to view kernel symbol addresses")
return
@register
class DetailRegistersCommand(GenericCommand):
"""Display full details on one, many or all registers value from current architecture."""
_cmdline_ = "registers"
_syntax_ = f"{_cmdline_} [[Register1][Register2] ... [RegisterN]]"
_example_ = (f"\n{_cmdline_}"
f"\n{_cmdline_} $eax $eip $esp")
@only_if_gdb_running
@parse_arguments({"registers": [""]}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
unchanged_color = gef.config["theme.registers_register_name"]
changed_color = gef.config["theme.registers_value_changed"]
string_color = gef.config["theme.dereference_string"]
regs = gef.arch.all_registers
args : argparse.Namespace = kwargs["arguments"]
if args.registers and args.registers[0]:
required_regs = set(args.registers)
valid_regs = [reg for reg in gef.arch.all_registers if reg in required_regs]
if valid_regs:
regs = valid_regs
invalid_regs = [reg for reg in required_regs if reg not in valid_regs]
if invalid_regs:
err(f"invalid registers for architecture: {', '.join(invalid_regs)}")
memsize = gef.arch.ptrsize
endian = str(gef.arch.endianness)
charset = string.printable
widest = max(map(len, gef.arch.all_registers))
special_line = ""
for regname in regs:
reg = gdb.parse_and_eval(regname)
if reg.type.code == gdb.TYPE_CODE_VOID:
continue
padreg = regname.ljust(widest, " ")
if str(reg) == "<unavailable>":
gef_print(f"{Color.colorify(padreg, unchanged_color)}: "
f"{Color.colorify('no value', 'yellow underline')}")
continue
value = align_address(int(reg))
old_value = ContextCommand.old_registers.get(regname, 0)
if value == old_value:
color = unchanged_color
else:
color = changed_color
# Special (e.g. segment) registers go on their own line
if regname in gef.arch.special_registers:
special_line += f"{Color.colorify(regname, color)}: "
special_line += f"{gef.arch.register(regname):#04x} "
continue
line = f"{Color.colorify(padreg, color)}: "
if regname == gef.arch.flag_register:
line += gef.arch.flag_register_to_human()
gef_print(line)
continue
addr = lookup_address(align_address(int(value)))
if addr.valid:
line += str(addr)
else:
line += format_address_spaces(value)
addrs = dereference_from(value)
if len(addrs) > 1:
sep = f" {RIGHT_ARROW} "
line += sep
line += sep.join(addrs[1:])
# check to see if reg value is ascii
try:
fmt = f"{endian}{'I' if memsize == 4 else 'Q'}"
last_addr = int(addrs[-1], 16)
val = gef_pystring(struct.pack(fmt, last_addr))
if all([_ in charset for _ in val]):
line += f" (\"{Color.colorify(val, string_color)}\"?)"
except ValueError:
pass
gef_print(line)
if special_line:
gef_print(special_line)
return
@register
class ShellcodeCommand(GenericCommand):
"""ShellcodeCommand uses @JonathanSalwan simple-yet-awesome shellcode API to
download shellcodes."""
_cmdline_ = "shellcode"
_syntax_ = f"{_cmdline_} (search|get)"
def __init__(self) -> None:
super().__init__(prefix=True)
return
def do_invoke(self, _: List[str]) -> None:
err("Missing sub-command (search|get)")
self.usage()
return
@register
class ShellcodeSearchCommand(GenericCommand):
"""Search pattern in shell-storm's shellcode database."""
_cmdline_ = "shellcode search"
_syntax_ = f"{_cmdline_} PATTERN1 PATTERN2"
_aliases_ = ["sc-search",]
api_base = "http://shell-storm.org"
search_url = f"{api_base}/api/?s="
def do_invoke(self, argv: List[str]) -> None:
if not argv:
err("Missing pattern to search")
self.usage()
return
self.search_shellcode(argv)
return
def search_shellcode(self, search_options: List) -> None:
# API : http://shell-storm.org/shellcode/
args = "*".join(search_options)
res = http_get(self.search_url + args)
if res is None:
err("Could not query search page")
return
ret = gef_pystring(res)
# format: [author, OS/arch, cmd, id, link]
lines = ret.split("\\n")
refs = [line.split("::::") for line in lines]
if refs:
info("Showing matching shellcodes")
info("\t".join(["Id", "Platform", "Description"]))
for ref in refs:
try:
_, arch, cmd, sid, _ = ref
gef_print("\t".join([sid, arch, cmd]))
except ValueError:
continue
info("Use `shellcode get <id>` to fetch shellcode")
return
@register
class ShellcodeGetCommand(GenericCommand):
"""Download shellcode from shell-storm's shellcode database."""
_cmdline_ = "shellcode get"
_syntax_ = f"{_cmdline_} SHELLCODE_ID"
_aliases_ = ["sc-get",]
api_base = "http://shell-storm.org"
get_url = f"{api_base}/shellcode/files/shellcode-{{:d}}.html"
def do_invoke(self, argv: List[str]) -> None:
if len(argv) != 1:
err("Missing ID to download")
self.usage()
return
if not argv[0].isdigit():
err("ID is not a number")
self.usage()
return
self.get_shellcode(int(argv[0]))
return
def get_shellcode(self, sid: int) -> None:
info(f"Downloading shellcode id={sid}")
res = http_get(self.get_url.format(sid))
if res is None:
err(f"Failed to fetch shellcode #{sid}")
return
ok("Downloaded, written to disk...")
with tempfile.NamedTemporaryFile(prefix="sc-", suffix=".txt", mode='w+b', delete=False, dir=gef.config["gef.tempdir"]) as fd:
shellcode = res.split(b"<pre>")[1].split(b"</pre>")[0]
shellcode = shellcode.replace(b"&quot;", b'"')
fd.write(shellcode)
ok(f"Shellcode written to '{fd.name}'")
return
@register
class ProcessListingCommand(GenericCommand):
"""List and filter process. If a PATTERN is given as argument, results shown will be grepped
by this pattern."""
_cmdline_ = "process-search"
_syntax_ = f"{_cmdline_} [-h] [--attach] [--smart-scan] [REGEX_PATTERN]"
_aliases_ = ["ps"]
_example_ = f"{_cmdline_} gdb.*"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
self["ps_command"] = (f"{gef.session.constants['ps']} auxww", "`ps` command to get process information")
return
@parse_arguments({"pattern": ""}, {"--attach": True, "--smart-scan": True})
def do_invoke(self, _: List, **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
do_attach = args.attach
smart_scan = args.smart_scan
pattern = args.pattern
pattern = re.compile("^.*$") if not args else re.compile(pattern)
for process in self.get_processes():
pid = int(process["pid"])
command = process["command"]
if not re.search(pattern, command):
continue
if smart_scan:
if command.startswith("[") and command.endswith("]"): continue
if command.startswith("socat "): continue
if command.startswith("grep "): continue
if command.startswith("gdb "): continue
if args and do_attach:
ok(f"Attaching to process='{process['command']}' pid={pid:d}")
gdb.execute(f"attach {pid:d}")
return None
line = [process[i] for i in ("pid", "user", "cpu", "mem", "tty", "command")]
gef_print("\t\t".join(line))
return None
def get_processes(self) -> Generator[Dict[str, str], None, None]:
output = gef_execute_external(self["ps_command"].split(), True)
names = [x.lower().replace("%", "") for x in output[0].split()]
for line in output[1:]:
fields = line.split()
t = {}
for i, name in enumerate(names):
if i == len(names) - 1:
t[name] = " ".join(fields[i:])
else:
t[name] = fields[i]
yield t
return
@register
class ElfInfoCommand(GenericCommand):
"""Display a limited subset of ELF header information. If no argument is provided, the command will
show information about the current ELF being debugged."""
_cmdline_ = "elf-info"
_syntax_ = f"{_cmdline_} [FILE]"
_example_ = f"{_cmdline_} /bin/ls"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@parse_arguments({}, {"--filename": ""})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if is_qemu_system():
err("Unsupported")
return
filename = args.filename or get_filepath()
if filename is None:
return
try:
elf = Elf(filename)
except ValueError as ve:
err(f"`{filename}` is an invalid value for ELF file")
return
data = [
("Magic", f"{hexdump(struct.pack('>I', elf.e_magic), show_raw=True)}"),
("Class", f"{elf.e_class.value:#x} - {elf.e_class.name}"),
("Endianness", f"{elf.e_endianness.value:#x} - {Endianness(elf.e_endianness).name}"),
("Version", f"{elf.e_eiversion:#x}"),
("OS ABI", f"{elf.e_osabi.value:#x} - {elf.e_osabi.name if elf.e_osabi else ''}"),
("ABI Version", f"{elf.e_abiversion:#x}"),
("Type", f"{elf.e_type.value:#x} - {elf.e_type.name}"),
("Machine", f"{elf.e_machine.value:#x} - {elf.e_machine.name}"),
("Program Header Table", f"{format_address(elf.e_phoff)}"),
("Section Header Table", f"{format_address(elf.e_shoff)}"),
("Header Table", f"{format_address(elf.e_phoff)}"),
("ELF Version", f"{elf.e_version:#x}"),
("Header size", "{0} ({0:#x})".format(elf.e_ehsize)),
("Entry point", f"{format_address(elf.e_entry)}"),
]
for title, content in data:
gef_print(f"{Color.boldify(f'{title:<22}')}: {content}")
gef_print("")
gef_print(titlify("Program Header"))
gef_print(" [{:>2s}] {:12s} {:>8s} {:>10s} {:>10s} {:>8s} {:>8s} {:5s} {:>8s}".format(
"#", "Type", "Offset", "Virtaddr", "Physaddr", "FileSiz", "MemSiz", "Flags", "Align"))
for i, p in enumerate(elf.phdrs):
p_type = p.p_type.name if p.p_type else ""
p_flags = str(p.p_flags.name).lstrip("Flag.") if p.p_flags else "???"
gef_print(" [{:2d}] {:12s} {:#8x} {:#10x} {:#10x} {:#8x} {:#8x} {:5s} {:#8x}".format(
i, p_type, p.p_offset, p.p_vaddr, p.p_paddr, p.p_filesz, p.p_memsz, p_flags, p.p_align))
gef_print("")
gef_print(titlify("Section Header"))
gef_print(" [{:>2s}] {:20s} {:>15s} {:>10s} {:>8s} {:>8s} {:>8s} {:5s} {:4s} {:4s} {:>8s}".format(
"#", "Name", "Type", "Address", "Offset", "Size", "EntSiz", "Flags", "Link", "Info", "Align"))
for i, s in enumerate(elf.shdrs):
sh_type = s.sh_type.name if s.sh_type else "UNKN"
sh_flags = str(s.sh_flags).lstrip("Flags.") if s.sh_flags else "UNKN"
gef_print(f" [{i:2d}] {s.name:20s} {sh_type:>15s} {s.sh_addr:#10x} {s.sh_offset:#8x} "
f"{s.sh_size:#8x} {s.sh_entsize:#8x} {sh_flags:5s} {s.sh_link:#4x} {s.sh_info:#4x} {s.sh_addralign:#8x}")
return
@register
class EntryPointBreakCommand(GenericCommand):
"""Tries to find best entry point and sets a temporary breakpoint on it. The command will test for
well-known symbols for entry points, such as `main`, `_main`, `__libc_start_main`, etc. defined by
the setting `entrypoint_symbols`."""
_cmdline_ = "entry-break"
_syntax_ = _cmdline_
_aliases_ = ["start",]
def __init__(self) -> None:
super().__init__()
self["entrypoint_symbols"] = ("main _main __libc_start_main __uClibc_main start _start", "Possible symbols for entry points")
return
def do_invoke(self, argv: List[str]) -> None:
fpath = get_filepath()
if fpath is None:
warn("No executable to debug, use `file` to load a binary")
return
if not os.access(fpath, os.X_OK):
warn(f"The file '{fpath}' is not executable.")
return
if is_alive() and not gef.session.qemu_mode:
warn("gdb is already running")
return
bp = None
entrypoints = self["entrypoint_symbols"].split()
for sym in entrypoints:
try:
value = parse_address(sym)
info(f"Breaking at '{value:#x}'")
bp = EntryBreakBreakpoint(sym)
gdb.execute(f"run {' '.join(argv)}")
return
except gdb.error as gdb_error:
if 'The "remote" target does not support "run".' in str(gdb_error):
# this case can happen when doing remote debugging
gdb.execute("continue")
return
continue
# if here, clear the breakpoint if any set
if bp:
bp.delete()
# break at entry point
entry = gef.binary.entry_point
if is_pie(fpath):
self.set_init_tbreak_pie(entry, argv)
gdb.execute("continue")
return
self.set_init_tbreak(entry)
gdb.execute(f"run {' '.join(argv)}")
return
def set_init_tbreak(self, addr: int) -> EntryBreakBreakpoint:
info(f"Breaking at entry-point: {addr:#x}")
bp = EntryBreakBreakpoint(f"*{addr:#x}")
return bp
def set_init_tbreak_pie(self, addr: int, argv: List[str]) -> EntryBreakBreakpoint:
warn("PIC binary detected, retrieving text base address")
gdb.execute("set stop-on-solib-events 1")
hide_context()
gdb.execute(f"run {' '.join(argv)}")
unhide_context()
gdb.execute("set stop-on-solib-events 0")
vmmap = gef.memory.maps
base_address = [x.page_start for x in vmmap if x.path == get_filepath()][0]
return self.set_init_tbreak(base_address + addr)
@register
class NamedBreakpointCommand(GenericCommand):
"""Sets a breakpoint and assigns a name to it, which will be shown, when it's hit."""
_cmdline_ = "name-break"
_syntax_ = f"{_cmdline_} name [address]"
_aliases_ = ["nb",]
_example = f"{_cmdline_} main *0x4008a9"
def __init__(self) -> None:
super().__init__()
return
@parse_arguments({"name": "", "address": "*$pc"}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not args.name:
err("Missing name for breakpoint")
self.usage()
return
NamedBreakpoint(args.address, args.name)
return
@register
class ContextCommand(GenericCommand):
"""Displays a comprehensive and modular summary of runtime context. Unless setting `enable` is
set to False, this command will be spawned automatically every time GDB hits a breakpoint, a
watchpoint, or any kind of interrupt. By default, it will show panes that contain the register
states, the stack, and the disassembly code around $pc."""
_cmdline_ = "context"
_syntax_ = f"{_cmdline_} [legend|regs|stack|code|args|memory|source|trace|threads|extra]"
_aliases_ = ["ctx",]
old_registers: Dict[str, Optional[int]] = {}
def __init__(self) -> None:
super().__init__()
self["enable"] = (True, "Enable/disable printing the context when breaking")
self["show_source_code_variable_values"] = (True, "Show extra PC context info in the source code")
self["show_stack_raw"] = (False, "Show the stack pane as raw hexdump (no dereference)")
self["show_registers_raw"] = (False, "Show the registers pane with raw values (no dereference)")
self["show_opcodes_size"] = (0, "Number of bytes of opcodes to display next to the disassembly")
self["peek_calls"] = (True, "Peek into calls")
self["peek_ret"] = (True, "Peek at return address")
self["nb_lines_stack"] = (8, "Number of line in the stack pane")
self["grow_stack_down"] = (False, "Order of stack downward starts at largest down to stack pointer")
self["nb_lines_backtrace"] = (10, "Number of line in the backtrace pane")
self["nb_lines_backtrace_before"] = (2, "Number of line in the backtrace pane before selected frame")
self["nb_lines_threads"] = (-1, "Number of line in the threads pane")
self["nb_lines_code"] = (6, "Number of instruction after $pc")
self["nb_lines_code_prev"] = (3, "Number of instruction before $pc")
self["ignore_registers"] = ("", "Space-separated list of registers not to display (e.g. '$cs $ds $gs')")
self["clear_screen"] = (True, "Clear the screen before printing the context")
self["layout"] = ("legend regs stack code args source memory threads trace extra", "Change the order/presence of the context sections")
self["redirect"] = ("", "Redirect the context information to another TTY")
self["libc_args"] = (False, "[DEPRECATED - Unused] Show libc function call args description")
self["libc_args_path"] = ("", "[DEPRECATED - Unused] Path to libc function call args json files, provided via gef-extras")
self.layout_mapping = {
"legend": (self.show_legend, None, None),
"regs": (self.context_regs, None, None),
"stack": (self.context_stack, None, None),
"code": (self.context_code, None, None),
"args": (self.context_args, None, None),
"memory": (self.context_memory, None, None),
"source": (self.context_source, None, None),
"trace": (self.context_trace, None, None),
"threads": (self.context_threads, None, None),
"extra": (self.context_additional_information, None, None),
}
self.instruction_iterator = gef_disassemble
return
def post_load(self) -> None:
gef_on_continue_hook(self.update_registers)
gef_on_continue_hook(self.empty_extra_messages)
return
def show_legend(self) -> None:
if gef.config["gef.disable_color"] is True:
return
str_color = gef.config["theme.dereference_string"]
code_addr_color = gef.config["theme.address_code"]
stack_addr_color = gef.config["theme.address_stack"]
heap_addr_color = gef.config["theme.address_heap"]
changed_register_color = gef.config["theme.registers_value_changed"]
gef_print("[ Legend: {} | {} | {} | {} | {} ]".format(Color.colorify("Modified register", changed_register_color),
Color.colorify("Code", code_addr_color),
Color.colorify("Heap", heap_addr_color),
Color.colorify("Stack", stack_addr_color),
Color.colorify("String", str_color)))
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if not self["enable"] or gef.ui.context_hidden:
return
if not all(_ in self.layout_mapping for _ in argv):
self.usage()
return
if len(argv) > 0:
current_layout = argv
else:
current_layout = self["layout"].strip().split()
if not current_layout:
return
self.tty_rows, self.tty_columns = get_terminal_size()
redirect = self["redirect"]
if redirect and os.access(redirect, os.W_OK):
enable_redirect_output(to_file=redirect)
for section in current_layout:
if section[0] == "-":
continue
try:
display_pane_function, pane_title_function, condition = self.layout_mapping[section]
if condition:
if not condition():
continue
if pane_title_function:
self.context_title(pane_title_function())
display_pane_function()
except gdb.MemoryError as e:
# a MemoryError will happen when $pc is corrupted (invalid address)
err(str(e))
except IndexError:
# the `section` is not present, just skip
pass
self.context_title("")
if self["clear_screen"] and len(argv) == 0:
clear_screen(redirect)
if redirect and os.access(redirect, os.W_OK):
disable_redirect_output()
return
def context_title(self, m: Optional[str]) -> None:
# allow for not displaying a title line
if m is None:
return
line_color = gef.config["theme.context_title_line"]
msg_color = gef.config["theme.context_title_message"]
# print an empty line in case of ""
if not m:
gef_print(Color.colorify(HORIZONTAL_LINE * self.tty_columns, line_color))
return
trail_len = len(m) + 6
title = ""
title += Color.colorify("{:{padd}<{width}} ".format("",
width=max(self.tty_columns - trail_len, 0),
padd=HORIZONTAL_LINE),
line_color)
title += Color.colorify(m, msg_color)
title += Color.colorify(" {:{padd}<4}".format("", padd=HORIZONTAL_LINE),
line_color)
gef_print(title)
return
def context_regs(self) -> None:
self.context_title("registers")
ignored_registers = set(self["ignore_registers"].split())
if self["show_registers_raw"] is False:
regs = set(gef.arch.all_registers)
printable_registers = " ".join(list(regs - ignored_registers))
gdb.execute(f"registers {printable_registers}")
return
widest = l = max(map(len, gef.arch.all_registers))
l += 5
l += gef.arch.ptrsize * 2
nb = get_terminal_size()[1] // l
i = 1
line = ""
changed_color = gef.config["theme.registers_value_changed"]
regname_color = gef.config["theme.registers_register_name"]
for reg in gef.arch.all_registers:
if reg in ignored_registers:
continue
try:
r = gdb.parse_and_eval(reg)
if r.type.code == gdb.TYPE_CODE_VOID:
continue
new_value_type_flag = r.type.code == gdb.TYPE_CODE_FLAGS
new_value = int(r)
except (gdb.MemoryError, gdb.error):
# If this exception is triggered, it means that the current register
# is corrupted. Just use the register "raw" value (not eval-ed)
new_value = gef.arch.register(reg)
new_value_type_flag = False
except Exception:
new_value = 0
new_value_type_flag = False
old_value = self.old_registers.get(reg, 0)
padreg = reg.ljust(widest, " ")
value = align_address(new_value)
old_value = align_address(old_value or 0)
if value == old_value:
line += f"{Color.colorify(padreg, regname_color)}: "
else:
line += f"{Color.colorify(padreg, changed_color)}: "
if new_value_type_flag:
line += f"{format_address_spaces(value)} "
else:
addr = lookup_address(align_address(int(value)))
if addr.valid:
line += f"{addr!s} "
else:
line += f"{format_address_spaces(value)} "
if i % nb == 0:
gef_print(line)
line = ""
i += 1
if line:
gef_print(line)
gef_print(f"Flags: {gef.arch.flag_register_to_human()}")
return
def context_stack(self) -> None:
self.context_title("stack")
show_raw = self["show_stack_raw"]
nb_lines = self["nb_lines_stack"]
try:
sp = gef.arch.sp
if show_raw is True:
mem = gef.memory.read(sp, 0x10 * nb_lines)
gef_print(hexdump(mem, base=sp))
else:
gdb.execute(f"dereference -l {nb_lines:d} {sp:#x}")
except gdb.MemoryError:
err("Cannot read memory from $SP (corrupted stack pointer?)")
return
def addr_has_breakpoint(self, address: int, bp_locations: List[str]) -> bool:
return any(hex(address) in b for b in bp_locations)
def context_code(self) -> None:
nb_insn = self["nb_lines_code"]
nb_insn_prev = self["nb_lines_code_prev"]
show_opcodes_size = "show_opcodes_size" in self and self["show_opcodes_size"]
past_insns_color = gef.config["theme.old_context"]
cur_insn_color = gef.config["theme.disassemble_current_instruction"]
pc = gef.arch.pc
breakpoints = gdb.breakpoints() or []
bp_locations = [b.location for b in breakpoints if b.location and b.location.startswith("*")]
frame = gdb.selected_frame()
arch_name = f"{gef.arch.arch.lower()}:{gef.arch.mode}"
self.context_title(f"code:{arch_name}")
try:
for insn in self.instruction_iterator(pc, nb_insn, nb_prev=nb_insn_prev):
line = []
is_taken = False
target = None
bp_prefix = Color.redify(BP_GLYPH) if self.addr_has_breakpoint(insn.address, bp_locations) else " "
if show_opcodes_size == 0:
text = str(insn)
else:
insn_fmt = f"{{:{show_opcodes_size}o}}"
text = insn_fmt.format(insn)
if insn.address < pc:
line += f"{bp_prefix} {Color.colorify(text, past_insns_color)}"
elif insn.address == pc:
line += f"{bp_prefix}{Color.colorify(f'{RIGHT_ARROW[1:]}{text}', cur_insn_color)}"
if gef.arch.is_conditional_branch(insn):
is_taken, reason = gef.arch.is_branch_taken(insn)
if is_taken:
target = insn.operands[-1].split()[0]
reason = f"[Reason: {reason}]" if reason else ""
line += Color.colorify(f"\tTAKEN {reason}", "bold green")
else:
reason = f"[Reason: !({reason})]" if reason else ""
line += Color.colorify(f"\tNOT taken {reason}", "bold red")
elif gef.arch.is_call(insn) and self["peek_calls"] is True:
target = insn.operands[-1].split()[0]
elif gef.arch.is_ret(insn) and self["peek_ret"] is True:
target = gef.arch.get_ra(insn, frame)
else:
line += f"{bp_prefix} {text}"
gef_print("".join(line))
if target:
try:
address = int(target, 0) if isinstance(target, str) else target
except ValueError:
# If the operand isn't an address right now we can't parse it
continue
for i, tinsn in enumerate(self.instruction_iterator(address, nb_insn)):
text= f" {DOWN_ARROW if i == 0 else ' '} {tinsn!s}"
gef_print(text)
break
except gdb.MemoryError:
err("Cannot disassemble from $PC")
return
def context_args(self) -> None:
insn = gef_current_instruction(gef.arch.pc)
if not gef.arch.is_call(insn):
return
self.size2type = {
1: "BYTE",
2: "WORD",
4: "DWORD",
8: "QWORD",
}
if insn.operands[-1].startswith(self.size2type[gef.arch.ptrsize]+" PTR"):
target = "*" + insn.operands[-1].split()[-1]
elif "$"+insn.operands[0] in gef.arch.all_registers:
target = f"*{gef.arch.register('$' + insn.operands[0]):#x}"
else:
# is there a symbol?
ops = " ".join(insn.operands)
if "<" in ops and ">" in ops:
# extract it
target = re.sub(r".*<([^\(> ]*).*", r"\1", ops)
else:
# it's an address, just use as is
target = re.sub(r".*(0x[a-fA-F0-9]*).*", r"\1", ops)
sym = gdb.lookup_global_symbol(target)
if sym is None:
self.print_guessed_arguments(target)
return
if sym.type.code != gdb.TYPE_CODE_FUNC:
err(f"Symbol '{target}' is not a function: type={sym.type.code}")
return
self.print_arguments_from_symbol(target, sym)
return
def print_arguments_from_symbol(self, function_name: str, symbol: "gdb.Symbol") -> None:
"""If symbols were found, parse them and print the argument adequately."""
args = []
for i, f in enumerate(symbol.type.fields()):
_value = gef.arch.get_ith_parameter(i, in_func=False)[1]
_value = RIGHT_ARROW.join(dereference_from(_value))
_name = f.name or f"var_{i}"
_type = f.type.name or self.size2type[f.type.sizeof]
args.append(f"{_type} {_name} = {_value}")
self.context_title("arguments")
if not args:
gef_print(f"{function_name} (<void>)")
return
gef_print(f"{function_name} (\n "+",\n ".join(args)+"\n)")
return
def print_guessed_arguments(self, function_name: str) -> None:
"""When no symbol, read the current basic block and look for "interesting" instructions."""
def __get_current_block_start_address() -> Optional[int]:
pc = gef.arch.pc
try:
block = gdb.block_for_pc(pc)
block_start = block.start if block else gdb_get_nth_previous_instruction_address(pc, 5)
except RuntimeError:
block_start = gdb_get_nth_previous_instruction_address(pc, 5)
return block_start
parameter_set = set()
pc = gef.arch.pc
block_start = __get_current_block_start_address()
if not block_start:
return
function_parameters = gef.arch.function_parameters
arg_key_color = gef.config["theme.registers_register_name"]
for insn in self.instruction_iterator(block_start, pc - block_start):
if not insn.operands:
continue
if is_x86_32():
if insn.mnemonic == "push":
parameter_set.add(insn.operands[0])
else:
op = "$" + insn.operands[0]
if op in function_parameters:
parameter_set.add(op)
if is_x86_64():
# also consider extended registers
extended_registers = {"$rdi": ["$edi", "$di"],
"$rsi": ["$esi", "$si"],
"$rdx": ["$edx", "$dx"],
"$rcx": ["$ecx", "$cx"],
}
for exreg in extended_registers:
if op in extended_registers[exreg]:
parameter_set.add(exreg)
if is_x86_32():
nb_argument = len(parameter_set)
else:
nb_argument = max([function_parameters.index(p)+1 for p in parameter_set], default=0)
args = []
for i in range(nb_argument):
_key, _values = gef.arch.get_ith_parameter(i, in_func=False)
_values = RIGHT_ARROW.join(dereference_from(_values))
args.append(f"{Color.colorify(_key, arg_key_color)} = {_values}")
self.context_title("arguments (guessed)")
gef_print(f"{function_name} (")
if args:
gef_print(" " + ",\n ".join(args))
gef_print(")")
return
def line_has_breakpoint(self, file_name: str, line_number: int, bp_locations: List[str]) -> bool:
filename_line = f"{file_name}:{line_number}"
return any(filename_line in loc for loc in bp_locations)
def context_source(self) -> None:
try:
pc = gef.arch.pc
symtabline = gdb.find_pc_line(pc)
symtab = symtabline.symtab
# we subtract one because the line number returned by gdb start at 1
line_num = symtabline.line - 1
if not symtab.is_valid():
return
fpath = symtab.fullname()
with open(fpath, "r") as f:
lines = [l.rstrip() for l in f.readlines()]
except Exception:
return
file_base_name = os.path.basename(symtab.filename)
breakpoints = gdb.breakpoints() or []
bp_locations = [b.location for b in breakpoints if b.location and file_base_name in b.location]
past_lines_color = gef.config["theme.old_context"]
nb_line = self["nb_lines_code"]
fn = symtab.filename
if len(fn) > 20:
fn = f"{fn[:15]}[...]{os.path.splitext(fn)[1]}"
title = f"source:{fn}+{line_num + 1}"
cur_line_color = gef.config["theme.source_current_line"]
self.context_title(title)
show_extra_info = self["show_source_code_variable_values"]
for i in range(line_num - nb_line + 1, line_num + nb_line):
if i < 0:
continue
bp_prefix = Color.redify(BP_GLYPH) if self.line_has_breakpoint(file_base_name, i + 1, bp_locations) else " "
if i < line_num:
gef_print("{}{}".format(bp_prefix, Color.colorify(f" {i + 1:4d}\t {lines[i]}", past_lines_color)))
if i == line_num:
prefix = f"{bp_prefix}{RIGHT_ARROW[1:]}{i + 1:4d}\t "
leading = len(lines[i]) - len(lines[i].lstrip())
if show_extra_info:
extra_info = self.get_pc_context_info(pc, lines[i])
if extra_info:
gef_print(f"{' ' * (len(prefix) + leading)}{extra_info}")
gef_print(Color.colorify(f"{prefix}{lines[i]}", cur_line_color))
if i > line_num:
try:
gef_print(f"{bp_prefix} {i + 1:4d}\t {lines[i]}")
except IndexError:
break
return
def get_pc_context_info(self, pc: int, line: str) -> str:
try:
current_block = gdb.block_for_pc(pc)
if not current_block or not current_block.is_valid(): return ""
m = collections.OrderedDict()
while current_block and not current_block.is_static:
for sym in current_block:
symbol = sym.name
if not sym.is_function and re.search(fr"\W{symbol}\W", line):
val = gdb.parse_and_eval(symbol)
if val.type.code in (gdb.TYPE_CODE_PTR, gdb.TYPE_CODE_ARRAY):
addr = int(val.address)
addrs = dereference_from(addr)
if len(addrs) > 2:
addrs = [addrs[0], "[...]", addrs[-1]]
f = f" {RIGHT_ARROW} "
val = f.join(addrs)
elif val.type.code == gdb.TYPE_CODE_INT:
val = hex(int(val))
else:
continue
if symbol not in m:
m[symbol] = val
current_block = current_block.superblock
if m:
return "// " + ", ".join([f"{Color.yellowify(a)}={b}" for a, b in m.items()])
except Exception:
pass
return ""
def context_trace(self) -> None:
self.context_title("trace")
nb_backtrace = self["nb_lines_backtrace"]
if nb_backtrace <= 0:
return
# backward compat for gdb (gdb < 7.10)
if not hasattr(gdb, "FrameDecorator"):
gdb.execute(f"backtrace {nb_backtrace:d}")
return
orig_frame = gdb.selected_frame()
current_frame = gdb.newest_frame()
frames = [current_frame]
while current_frame != orig_frame:
current_frame = current_frame.older()
frames.append(current_frame)
nb_backtrace_before = self["nb_lines_backtrace_before"]
level = max(len(frames) - nb_backtrace_before - 1, 0)
current_frame = frames[level]
while current_frame:
current_frame.select()
if not current_frame.is_valid():
continue
pc = current_frame.pc()
name = current_frame.name()
items = []
items.append(f"{pc:#x}")
if name:
frame_args = gdb.FrameDecorator.FrameDecorator(current_frame).frame_args() or []
m = "{}({})".format(Color.greenify(name),
", ".join(["{}={!s}".format(Color.yellowify(x.sym),
x.sym.value(current_frame)) for x in frame_args]))
items.append(m)
else:
try:
insn = next(gef_disassemble(pc, 1))
except gdb.MemoryError:
break
# check if the gdb symbol table may know the address
sym_found = gdb_get_location_from_symbol(pc)
symbol = ""
if sym_found:
sym_name, offset = sym_found
symbol = f" <{sym_name}+{offset:x}> "
items.append(Color.redify(f"{symbol}{insn.mnemonic} {', '.join(insn.operands)}"))
gef_print("[{}] {}".format(Color.colorify(f"#{level}", "bold green" if current_frame == orig_frame else "bold pink"),
RIGHT_ARROW.join(items)))
current_frame = current_frame.older()
level += 1
nb_backtrace -= 1
if nb_backtrace == 0:
break
orig_frame.select()
return
def context_threads(self) -> None:
def reason() -> str:
res = gdb.execute("info program", to_string=True)
if not res:
return "NOT RUNNING"
for line in res.splitlines():
line = line.strip()
if line.startswith("It stopped with signal "):
return line.replace("It stopped with signal ", "").split(",", 1)[0]
if line == "The program being debugged is not being run.":
return "NOT RUNNING"
if line == "It stopped at a breakpoint that has since been deleted.":
return "TEMPORARY BREAKPOINT"
if line.startswith("It stopped at breakpoint "):
return "BREAKPOINT"
if line == "It stopped after being stepped.":
return "SINGLE STEP"
return "STOPPED"
self.context_title("threads")
threads = gdb.selected_inferior().threads()[::-1]
idx = self["nb_lines_threads"]
if idx > 0:
threads = threads[0:idx]
if idx == 0:
return
if not threads:
err("No thread selected")
return
selected_thread = gdb.selected_thread()
selected_frame = gdb.selected_frame()
for i, thread in enumerate(threads):
line = f"[{Color.colorify(f'#{i:d}', 'bold green' if thread == selected_thread else 'bold pink')}] Id {thread.num:d}, "
if thread.name:
line += f"""Name: "{thread.name}", """
if thread.is_running():
line += Color.colorify("running", "bold green")
elif thread.is_stopped():
line += Color.colorify("stopped", "bold red")
thread.switch()
frame = gdb.selected_frame()
frame_name = frame.name()
# check if the gdb symbol table may know the address
if not frame_name:
sym_found = gdb_get_location_from_symbol(frame.pc())
if sym_found:
sym_name, offset = sym_found
frame_name = f"<{sym_name}+{offset:x}>"
line += (f" {Color.colorify(f'{frame.pc():#x}', 'blue')} in "
f"{Color.colorify(frame_name or '??', 'bold yellow')} (), "
f"reason: {Color.colorify(reason(), 'bold pink')}")
elif thread.is_exited():
line += Color.colorify("exited", "bold yellow")
gef_print(line)
i += 1
selected_thread.switch()
selected_frame.select()
return
def context_additional_information(self) -> None:
if not gef.ui.context_messages:
return
self.context_title("extra")
for level, text in gef.ui.context_messages:
if level == "error": err(text)
elif level == "warn": warn(text)
elif level == "success": ok(text)
else: info(text)
return
def context_memory(self) -> None:
for address, opt in sorted(gef.ui.watches.items()):
sz, fmt = opt[0:2]
self.context_title(f"memory:{address:#x}")
if fmt == "pointers":
gdb.execute(f"dereference -l {sz:d} {address:#x}")
else:
gdb.execute(f"hexdump {fmt} -s {sz:d} {address:#x}")
@classmethod
def update_registers(cls, _) -> None:
for reg in gef.arch.all_registers:
try:
cls.old_registers[reg] = gef.arch.register(reg)
except Exception:
cls.old_registers[reg] = 0
return
def empty_extra_messages(self, _) -> None:
gef.ui.context_messages.clear()
return
@register
class MemoryCommand(GenericCommand):
"""Add or remove address ranges to the memory view."""
_cmdline_ = "memory"
_syntax_ = f"{_cmdline_} (watch|unwatch|reset|list)"
def __init__(self) -> None:
super().__init__(prefix=True)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
self.usage()
return
@register
class MemoryWatchCommand(GenericCommand):
"""Adds address ranges to the memory view."""
_cmdline_ = "memory watch"
_syntax_ = f"{_cmdline_} ADDRESS [SIZE] [(qword|dword|word|byte|pointers)]"
_example_ = (f"\n{_cmdline_} 0x603000 0x100 byte"
f"\n{_cmdline_} $sp")
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if len(argv) not in (1, 2, 3):
self.usage()
return
address = parse_address(argv[0])
size = parse_address(argv[1]) if len(argv) > 1 else 0x10
group = "byte"
if len(argv) == 3:
group = argv[2].lower()
if group not in ("qword", "dword", "word", "byte", "pointers"):
warn(f"Unexpected grouping '{group}'")
self.usage()
return
else:
if gef.arch.ptrsize == 4:
group = "dword"
elif gef.arch.ptrsize == 8:
group = "qword"
gef.ui.watches[address] = (size, group)
ok(f"Adding memwatch to {address:#x}")
return
@register
class MemoryUnwatchCommand(GenericCommand):
"""Removes address ranges to the memory view."""
_cmdline_ = "memory unwatch"
_syntax_ = f"{_cmdline_} ADDRESS"
_example_ = (f"\n{_cmdline_} 0x603000"
f"\n{_cmdline_} $sp")
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if not argv:
self.usage()
return
address = parse_address(argv[0])
res = gef.ui.watches.pop(address, None)
if not res:
warn(f"You weren't watching {address:#x}")
else:
ok(f"Removed memwatch of {address:#x}")
return
@register
class MemoryWatchResetCommand(GenericCommand):
"""Removes all watchpoints."""
_cmdline_ = "memory reset"
_syntax_ = f"{_cmdline_}"
@only_if_gdb_running
def do_invoke(self, _: List[str]) -> None:
gef.ui.watches.clear()
ok("Memory watches cleared")
return
@register
class MemoryWatchListCommand(GenericCommand):
"""Lists all watchpoints to display in context layout."""
_cmdline_ = "memory list"
_syntax_ = f"{_cmdline_}"
@only_if_gdb_running
def do_invoke(self, _: List[str]) -> None:
if not gef.ui.watches:
info("No memory watches")
return
info("Memory watches:")
for address, opt in sorted(gef.ui.watches.items()):
gef_print(f"- {address:#x} ({opt[0]}, {opt[1]})")
return
@register
class HexdumpCommand(GenericCommand):
"""Display SIZE lines of hexdump from the memory location pointed by LOCATION."""
_cmdline_ = "hexdump"
_syntax_ = f"{_cmdline_} (qword|dword|word|byte) [LOCATION] [--size SIZE] [--reverse]"
_example_ = f"{_cmdline_} byte $rsp --size 16 --reverse"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION, prefix=True)
self["always_show_ascii"] = (False, "If true, hexdump will always display the ASCII dump")
self.format: Optional[str] = None
self.__last_target = "$sp"
return
@only_if_gdb_running
@parse_arguments({"address": "",}, {("--reverse", "-r"): True, ("--size", "-s"): 0})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
valid_formats = ["byte", "word", "dword", "qword"]
if not self.format or self.format not in valid_formats:
err("Invalid command")
return
args : argparse.Namespace = kwargs["arguments"]
target = args.address or self.__last_target
start_addr = parse_address(target)
read_from = align_address(start_addr)
if self.format == "byte":
read_len = args.size or 0x40
read_from += self.repeat_count * read_len
mem = gef.memory.read(read_from, read_len)
lines = hexdump(mem, base=read_from).splitlines()
else:
read_len = args.size or 0x10
lines = self._hexdump(read_from, read_len, self.format, self.repeat_count * read_len)
if args.reverse:
lines.reverse()
self.__last_target = target
gef_print("\n".join(lines))
return
def _hexdump(self, start_addr: int, length: int, arrange_as: str, offset: int = 0) -> List[str]:
endianness = gef.arch.endianness
base_address_color = gef.config["theme.dereference_base_address"]
show_ascii = gef.config["hexdump.always_show_ascii"]
formats = {
"qword": ("Q", 8),
"dword": ("I", 4),
"word": ("H", 2),
}
r, l = formats[arrange_as]
fmt_str = f"{{base}}{VERTICAL_LINE}+{{offset:#06x}} {{sym}}{{val:#0{l*2+2}x}} {{text}}"
fmt_pack = f"{endianness!s}{r}"
lines = []
i = 0
text = ""
while i < length:
cur_addr = start_addr + (i + offset) * l
sym = gdb_get_location_from_symbol(cur_addr)
sym = "<{:s}+{:04x}> ".format(*sym) if sym else ""
mem = gef.memory.read(cur_addr, l)
val = struct.unpack(fmt_pack, mem)[0]
if show_ascii:
text = "".join([chr(b) if 0x20 <= b < 0x7F else "." for b in mem])
lines.append(fmt_str.format(base=Color.colorify(format_address(cur_addr), base_address_color),
offset=(i + offset) * l, sym=sym, val=val, text=text))
i += 1
return lines
@register
class HexdumpQwordCommand(HexdumpCommand):
"""Display SIZE lines of hexdump as QWORD from the memory location pointed by ADDRESS."""
_cmdline_ = "hexdump qword"
_syntax_ = f"{_cmdline_} [ADDRESS] [[L][SIZE]] [REVERSE]"
_example_ = f"{_cmdline_} qword $rsp L16 REVERSE"
def __init__(self) -> None:
super().__init__()
self.format = "qword"
return
@register
class HexdumpDwordCommand(HexdumpCommand):
"""Display SIZE lines of hexdump as DWORD from the memory location pointed by ADDRESS."""
_cmdline_ = "hexdump dword"
_syntax_ = f"{_cmdline_} [ADDRESS] [[L][SIZE]] [REVERSE]"
_example_ = f"{_cmdline_} $esp L16 REVERSE"
def __init__(self) -> None:
super().__init__()
self.format = "dword"
return
@register
class HexdumpWordCommand(HexdumpCommand):
"""Display SIZE lines of hexdump as WORD from the memory location pointed by ADDRESS."""
_cmdline_ = "hexdump word"
_syntax_ = f"{_cmdline_} [ADDRESS] [[L][SIZE]] [REVERSE]"
_example_ = f"{_cmdline_} $esp L16 REVERSE"
def __init__(self) -> None:
super().__init__()
self.format = "word"
return
@register
class HexdumpByteCommand(HexdumpCommand):
"""Display SIZE lines of hexdump as BYTE from the memory location pointed by ADDRESS."""
_cmdline_ = "hexdump byte"
_syntax_ = f"{_cmdline_} [ADDRESS] [[L][SIZE]] [REVERSE]"
_example_ = f"{_cmdline_} $rsp L16"
def __init__(self) -> None:
super().__init__()
self.format = "byte"
return
@register
class PatchCommand(GenericCommand):
"""Write specified values to the specified address."""
_cmdline_ = "patch"
_syntax_ = (f"{_cmdline_} (qword|dword|word|byte) LOCATION VALUES\n"
f"{_cmdline_} string LOCATION \"double-escaped string\"")
SUPPORTED_SIZES = {
"qword": (8, "Q"),
"dword": (4, "L"),
"word": (2, "H"),
"byte": (1, "B"),
}
def __init__(self) -> None:
super().__init__(prefix=True, complete=gdb.COMPLETE_LOCATION)
self.format: Optional[str] = None
return
@only_if_gdb_running
@parse_arguments({"location": "", "values": ["", ]}, {})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
if not self.format or self.format not in self.SUPPORTED_SIZES:
self.usage()
return
if not args.location or not args.values:
self.usage()
return
addr = align_address(parse_address(args.location))
size, fcode = self.SUPPORTED_SIZES[self.format]
values = args.values
if size == 1:
if values[0].startswith("$_gef"):
var_name = values[0]
try:
values = str(gdb.parse_and_eval(var_name)).lstrip("{").rstrip("}").replace(",","").split(" ")
except:
gef_print(f"Bad variable specified, check value with command: p {var_name}")
return
d = str(gef.arch.endianness)
for value in values:
value = parse_address(value) & ((1 << size * 8) - 1)
vstr = struct.pack(d + fcode, value)
gef.memory.write(addr, vstr, length=size)
addr += size
return
@register
class PatchQwordCommand(PatchCommand):
"""Write specified QWORD to the specified address."""
_cmdline_ = "patch qword"
_syntax_ = f"{_cmdline_} LOCATION QWORD1 [QWORD2 [QWORD3..]]"
_example_ = f"{_cmdline_} $rip 0x4141414141414141"
def __init__(self) -> None:
super().__init__()
self.format = "qword"
return
@register
class PatchDwordCommand(PatchCommand):
"""Write specified DWORD to the specified address."""
_cmdline_ = "patch dword"
_syntax_ = f"{_cmdline_} LOCATION DWORD1 [DWORD2 [DWORD3..]]"
_example_ = f"{_cmdline_} $rip 0x41414141"
def __init__(self) -> None:
super().__init__()
self.format = "dword"
return
@register
class PatchWordCommand(PatchCommand):
"""Write specified WORD to the specified address."""
_cmdline_ = "patch word"
_syntax_ = f"{_cmdline_} LOCATION WORD1 [WORD2 [WORD3..]]"
_example_ = f"{_cmdline_} $rip 0x4141"
def __init__(self) -> None:
super().__init__()
self.format = "word"
return
@register
class PatchByteCommand(PatchCommand):
"""Write specified BYTE to the specified address."""
_cmdline_ = "patch byte"
_syntax_ = f"{_cmdline_} LOCATION BYTE1 [BYTE2 [BYTE3..]]"
_example_ = f"{_cmdline_} $pc 0x41 0x41 0x41 0x41 0x41"
def __init__(self) -> None:
super().__init__()
self.format = "byte"
return
@register
class PatchStringCommand(GenericCommand):
"""Write specified string to the specified memory location pointed by ADDRESS."""
_cmdline_ = "patch string"
_syntax_ = f"{_cmdline_} ADDRESS \"double backslash-escaped string\""
_example_ = f"{_cmdline_} $sp \"GEFROCKS\""
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
argc = len(argv)
if argc != 2:
self.usage()
return
location, s = argv[0:2]
addr = align_address(parse_address(location))
try:
s = codecs.escape_decode(s)[0]
except binascii.Error:
gef_print(f"Could not decode '\\xXX' encoded string \"{s}\"")
return
gef.memory.write(addr, s, len(s))
return
@lru_cache()
def dereference_from(address: int) -> List[str]:
if not is_alive():
return [format_address(address),]
code_color = gef.config["theme.dereference_code"]
string_color = gef.config["theme.dereference_string"]
max_recursion = gef.config["dereference.max_recursion"] or 10
addr = lookup_address(align_address(address))
msg = [format_address(addr.value),]
seen_addrs = set()
while addr.section and max_recursion:
if addr.value in seen_addrs:
msg.append("[loop detected]")
break
seen_addrs.add(addr.value)
max_recursion -= 1
# Is this value a pointer or a value?
# -- If it's a pointer, dereference
deref = addr.dereference()
if deref is None:
# if here, dereferencing addr has triggered a MemoryError, no need to go further
msg.append(str(addr))
break
new_addr = lookup_address(deref)
if new_addr.valid:
addr = new_addr
msg.append(str(addr))
continue
# -- Otherwise try to parse the value
if addr.section:
if addr.section.is_executable() and addr.is_in_text_segment() and not is_ascii_string(addr.value):
insn = gef_current_instruction(addr.value)
insn_str = f"{insn.location} {insn.mnemonic} {', '.join(insn.operands)}"
msg.append(Color.colorify(insn_str, code_color))
break
elif addr.section.permission & Permission.READ:
if is_ascii_string(addr.value):
s = gef.memory.read_cstring(addr.value)
if len(s) < gef.arch.ptrsize:
txt = f'{format_address(deref)} ("{Color.colorify(s, string_color)}"?)'
elif len(s) > 50:
txt = Color.colorify(f'"{s[:50]}[...]"', string_color)
else:
txt = Color.colorify(f'"{s}"', string_color)
msg.append(txt)
break
# if not able to parse cleanly, simply display and break
val = "{:#0{ma}x}".format(int(deref & 0xFFFFFFFFFFFFFFFF), ma=(gef.arch.ptrsize * 2 + 2))
msg.append(val)
break
return msg
@register
class DereferenceCommand(GenericCommand):
"""Dereference recursively from an address and display information. This acts like WinDBG `dps`
command."""
_cmdline_ = "dereference"
_syntax_ = f"{_cmdline_} [-h] [--length LENGTH] [--reference REFERENCE] [address]"
_aliases_ = ["telescope", ]
_example_ = f"{_cmdline_} --length 20 --reference $sp+0x10 $sp"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
self["max_recursion"] = (7, "Maximum level of pointer recursion")
return
@staticmethod
def pprint_dereferenced(addr: int, idx: int, base_offset: int = 0) -> str:
base_address_color = gef.config["theme.dereference_base_address"]
registers_color = gef.config["theme.dereference_register_value"]
sep = f" {RIGHT_ARROW} "
memalign = gef.arch.ptrsize
offset = idx * memalign
current_address = align_address(addr + offset)
addrs = dereference_from(current_address)
l = ""
addr_l = format_address(int(addrs[0], 16))
l += "{}{}{:+#07x}: {:{ma}s}".format(Color.colorify(addr_l, base_address_color),
VERTICAL_LINE, base_offset+offset,
sep.join(addrs[1:]), ma=(memalign*2 + 2))
register_hints = []
for regname in gef.arch.all_registers:
regvalue = gef.arch.register(regname)
if current_address == regvalue:
register_hints.append(regname)
if register_hints:
m = f"\t{LEFT_ARROW}{', '.join(list(register_hints))}"
l += Color.colorify(m, registers_color)
offset += memalign
return l
@only_if_gdb_running
@parse_arguments({"address": "$sp"}, {("-r", "--reference"): "", ("-l", "--length"): 10})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
nb = args.length
target = args.address
target_addr = parse_address(target)
reference = args.reference or target
ref_addr = parse_address(reference)
if process_lookup_address(target_addr) is None:
err(f"Unmapped address: '{target}'")
return
if process_lookup_address(ref_addr) is None:
err(f"Unmapped address: '{reference}'")
return
if gef.config["context.grow_stack_down"] is True:
insnum_step = -1
if nb > 0:
from_insnum = nb * (self.repeat_count + 1) - 1
to_insnum = self.repeat_count * nb - 1
else:
from_insnum = self.repeat_count * nb
to_insnum = nb * (self.repeat_count + 1)
else:
insnum_step = 1
if nb > 0:
from_insnum = self.repeat_count * nb
to_insnum = nb * (self.repeat_count + 1)
else:
from_insnum = nb * (self.repeat_count + 1) + 1
to_insnum = (self.repeat_count * nb) + 1
start_address = align_address(target_addr)
base_offset = start_address - align_address(ref_addr)
for i in range(from_insnum, to_insnum, insnum_step):
gef_print(DereferenceCommand.pprint_dereferenced(start_address, i, base_offset))
return
@register
class ASLRCommand(GenericCommand):
"""View/modify the ASLR setting of GDB. By default, GDB will disable ASLR when it starts the process. (i.e. not
attached). This command allows to change that setting."""
_cmdline_ = "aslr"
_syntax_ = f"{_cmdline_} [(on|off)]"
def do_invoke(self, argv: List[str]) -> None:
argc = len(argv)
if argc == 0:
ret = gdb.execute("show disable-randomization", to_string=True) or ""
i = ret.find("virtual address space is ")
if i < 0:
return
msg = "ASLR is currently "
if ret[i + 25:].strip() == "on.":
msg += Color.redify("disabled")
else:
msg += Color.greenify("enabled")
gef_print(msg)
return
elif argc == 1:
if argv[0] == "on":
info("Enabling ASLR")
gdb.execute("set disable-randomization off")
return
elif argv[0] == "off":
info("Disabling ASLR")
gdb.execute("set disable-randomization on")
return
warn("Invalid command")
self.usage()
return
@register
class ResetCacheCommand(GenericCommand):
"""Reset cache of all stored data. This command is here for debugging and test purposes, GEF
handles properly the cache reset under "normal" scenario."""
_cmdline_ = "reset-cache"
_syntax_ = _cmdline_
def do_invoke(self, _: List[str]) -> None:
reset_all_caches()
return
@register
class VMMapCommand(GenericCommand):
"""Display a comprehensive layout of the virtual memory mapping. If a filter argument, GEF will
filter out the mapping whose pathname do not match that filter."""
_cmdline_ = "vmmap"
_syntax_ = f"{_cmdline_} [FILTER]"
_example_ = f"{_cmdline_} libc"
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
vmmap = gef.memory.maps
if not vmmap:
err("No address mapping information found")
return
if not gef.config["gef.disable_color"]:
self.show_legend()
color = gef.config["theme.table_heading"]
headers = ["Start", "End", "Offset", "Perm", "Path"]
gef_print(Color.colorify("{:<{w}s}{:<{w}s}{:<{w}s}{:<4s} {:s}".format(*headers, w=gef.arch.ptrsize*2+3), color))
for entry in vmmap:
if not argv:
self.print_entry(entry)
continue
if argv[0] in entry.path:
self.print_entry(entry)
elif self.is_integer(argv[0]):
addr = int(argv[0], 0)
if addr >= entry.page_start and addr < entry.page_end:
self.print_entry(entry)
return
def print_entry(self, entry: Section) -> None:
line_color = ""
if entry.path == "[stack]":
line_color = gef.config["theme.address_stack"]
elif entry.path == "[heap]":
line_color = gef.config["theme.address_heap"]
elif entry.permission & Permission.READ and entry.permission & Permission.EXECUTE:
line_color = gef.config["theme.address_code"]
l = [
Color.colorify(format_address(entry.page_start), line_color),
Color.colorify(format_address(entry.page_end), line_color),
Color.colorify(format_address(entry.offset), line_color),
]
if entry.permission == Permission.ALL:
l.append(Color.colorify(str(entry.permission), "underline " + line_color))
else:
l.append(Color.colorify(str(entry.permission), line_color))
l.append(Color.colorify(entry.path, line_color))
line = " ".join(l)
gef_print(line)
return
def show_legend(self) -> None:
code_addr_color = gef.config["theme.address_code"]
stack_addr_color = gef.config["theme.address_stack"]
heap_addr_color = gef.config["theme.address_heap"]
gef_print("[ Legend: {} | {} | {} ]".format(Color.colorify("Code", code_addr_color),
Color.colorify("Heap", heap_addr_color),
Color.colorify("Stack", stack_addr_color)
))
return
def is_integer(self, n: str) -> bool:
try:
int(n, 0)
except ValueError:
return False
return True
@register
class XFilesCommand(GenericCommand):
"""Shows all libraries (and sections) loaded by binary. This command extends the GDB command
`info files`, by retrieving more information from extra sources, and providing a better
display. If an argument FILE is given, the output will grep information related to only that file.
If an argument name is also given, the output will grep to the name within FILE."""
_cmdline_ = "xfiles"
_syntax_ = f"{_cmdline_} [FILE [NAME]]"
_example_ = f"\n{_cmdline_} libc\n{_cmdline_} libc IO_vtables"
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
color = gef.config["theme.table_heading"]
headers = ["Start", "End", "Name", "File"]
gef_print(Color.colorify("{:<{w}s}{:<{w}s}{:<21s} {:s}".format(*headers, w=gef.arch.ptrsize*2+3), color))
filter_by_file = argv[0] if argv and argv[0] else None
filter_by_name = argv[1] if len(argv) > 1 and argv[1] else None
for xfile in get_info_files():
if filter_by_file:
if filter_by_file not in xfile.filename:
continue
if filter_by_name and filter_by_name not in xfile.name:
continue
l = [
format_address(xfile.zone_start),
format_address(xfile.zone_end),
f"{xfile.name:<21s}",
xfile.filename,
]
gef_print(" ".join(l))
return
@register
class XAddressInfoCommand(GenericCommand):
"""Retrieve and display runtime information for the location(s) given as parameter."""
_cmdline_ = "xinfo"
_syntax_ = f"{_cmdline_} LOCATION"
_example_ = f"{_cmdline_} $pc"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_LOCATION)
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if not argv:
err("At least one valid address must be specified")
self.usage()
return
for sym in argv:
try:
addr = align_address(parse_address(sym))
gef_print(titlify(f"xinfo: {addr:#x}"))
self.infos(addr)
except gdb.error as gdb_err:
err(f"{gdb_err}")
return
def infos(self, address: int) -> None:
addr = lookup_address(address)
if not addr.valid:
warn(f"Cannot reach {address:#x} in memory space")
return
sect = addr.section
info = addr.info
if sect:
gef_print(f"Page: {format_address(sect.page_start)} {RIGHT_ARROW} "
f"{format_address(sect.page_end)} (size={sect.page_end-sect.page_start:#x})"
f"\nPermissions: {sect.permission}"
f"\nPathname: {sect.path}"
f"\nOffset (from page): {addr.value-sect.page_start:#x}"
f"\nInode: {sect.inode}")
if info:
gef_print(f"Segment: {info.name} "
f"({format_address(info.zone_start)}-{format_address(info.zone_end)})"
f"\nOffset (from segment): {addr.value-info.zone_start:#x}")
sym = gdb_get_location_from_symbol(address)
if sym:
name, offset = sym
msg = f"Symbol: {name}"
if offset:
msg += f"+{offset:d}"
gef_print(msg)
return
@register
class XorMemoryCommand(GenericCommand):
"""XOR a block of memory. The command allows to simply display the result, or patch it
runtime at runtime."""
_cmdline_ = "xor-memory"
_syntax_ = f"{_cmdline_} (display|patch) ADDRESS SIZE KEY"
def __init__(self) -> None:
super().__init__(prefix=True)
return
def do_invoke(self, _: List[str]) -> None:
self.usage()
return
@register
class XorMemoryDisplayCommand(GenericCommand):
"""Display a block of memory pointed by ADDRESS by xor-ing each byte with KEY. The key must be
provided in hexadecimal format."""
_cmdline_ = "xor-memory display"
_syntax_ = f"{_cmdline_} ADDRESS SIZE KEY"
_example_ = f"{_cmdline_} $sp 16 41414141"
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if len(argv) != 3:
self.usage()
return
address = parse_address(argv[0])
length = int(argv[1], 0)
key = argv[2]
block = gef.memory.read(address, length)
info(f"Displaying XOR-ing {address:#x}-{address + len(block):#x} with {key!r}")
gef_print(titlify("Original block"))
gef_print(hexdump(block, base=address))
gef_print(titlify("XOR-ed block"))
gef_print(hexdump(xor(block, key), base=address))
return
@register
class XorMemoryPatchCommand(GenericCommand):
"""Patch a block of memory pointed by ADDRESS by xor-ing each byte with KEY. The key must be
provided in hexadecimal format."""
_cmdline_ = "xor-memory patch"
_syntax_ = f"{_cmdline_} ADDRESS SIZE KEY"
_example_ = f"{_cmdline_} $sp 16 41414141"
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if len(argv) != 3:
self.usage()
return
address = parse_address(argv[0])
length = int(argv[1], 0)
key = argv[2]
block = gef.memory.read(address, length)
info(f"Patching XOR-ing {address:#x}-{address + len(block):#x} with {key!r}")
xored_block = xor(block, key)
gef.memory.write(address, xored_block, length)
return
@register
class TraceRunCommand(GenericCommand):
"""Create a runtime trace of all instructions executed from $pc to LOCATION specified. The
trace is stored in a text file that can be next imported in IDA Pro to visualize the runtime
path."""
_cmdline_ = "trace-run"
_syntax_ = f"{_cmdline_} LOCATION [MAX_CALL_DEPTH]"
_example_ = f"{_cmdline_} 0x555555554610"
def __init__(self) -> None:
super().__init__(self._cmdline_, complete=gdb.COMPLETE_LOCATION)
self["max_tracing_recursion"] = (1, "Maximum depth of tracing")
self["tracefile_prefix"] = ("./gef-trace-", "Specify the tracing output file prefix")
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
if len(argv) not in (1, 2):
self.usage()
return
if len(argv) == 2 and argv[1].isdigit():
depth = int(argv[1])
else:
depth = 1
try:
loc_start = gef.arch.pc
loc_end = parse_address(argv[0])
except gdb.error as e:
err(f"Invalid location: {e}")
return
self.trace(loc_start, loc_end, depth)
return
def get_frames_size(self) -> int:
n = 0
f = gdb.newest_frame()
while f:
n += 1
f = f.older()
return n
def trace(self, loc_start: int, loc_end: int, depth: int) -> None:
info(f"Tracing from {loc_start:#x} to {loc_end:#x} (max depth={depth:d})")
logfile = f"{self['tracefile_prefix']}{loc_start:#x}-{loc_end:#x}.txt"
with RedirectOutputContext(to=logfile):
hide_context()
self.start_tracing(loc_start, loc_end, depth)
unhide_context()
ok(f"Done, logfile stored as '{logfile}'")
info("Hint: import logfile with `ida_color_gdb_trace.py` script in IDA to visualize path")
return
def start_tracing(self, loc_start: int, loc_end: int, depth: int) -> None:
loc_cur = loc_start
frame_count_init = self.get_frames_size()
gef_print("#",
f"# Execution tracing of {get_filepath()}",
f"# Start address: {format_address(loc_start)}",
f"# End address: {format_address(loc_end)}",
f"# Recursion level: {depth:d}",
"# automatically generated by gef.py",
"#\n", sep="\n")
while loc_cur != loc_end:
try:
delta = self.get_frames_size() - frame_count_init
if delta <= depth:
gdb.execute("stepi")
else:
gdb.execute("finish")
loc_cur = gef.arch.pc
gdb.flush()
except gdb.error as e:
gef_print("#",
f"# Execution interrupted at address {format_address(loc_cur)}",
f"# Exception: {e}",
"#\n", sep="\n")
break
return
@register
class PatternCommand(GenericCommand):
"""Generate or Search a De Bruijn Sequence of unique substrings of length N
and a total length of LENGTH. The default value of N is set to match the
currently loaded architecture."""
_cmdline_ = "pattern"
_syntax_ = f"{_cmdline_} (create|search) ARGS"
def __init__(self) -> None:
super().__init__(prefix=True)
self["length"] = (1024, "Default length of a cyclic buffer to generate")
return
def do_invoke(self, _: List[str]) -> None:
self.usage()
return
@register
class PatternCreateCommand(GenericCommand):
"""Generate a De Bruijn Sequence of unique substrings of length N and a
total length of LENGTH. The default value of N is set to match the currently
loaded architecture."""
_cmdline_ = "pattern create"
_syntax_ = f"{_cmdline_} [-h] [-n N] [length]"
_example_ = f"{_cmdline_} 4096"
@parse_arguments({"length": 0}, {("-n", "--n"): 0})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args : argparse.Namespace = kwargs["arguments"]
length = args.length or gef.config["pattern.length"]
n = args.n or gef.arch.ptrsize
info(f"Generating a pattern of {length:d} bytes (n={n:d})")
pattern_str = gef_pystring(generate_cyclic_pattern(length, n))
gef_print(pattern_str)
ok(f"Saved as '{gef_convenience(pattern_str)}'")
return
@register
class PatternSearchCommand(GenericCommand):
"""Search a De Bruijn Sequence of unique substrings of length N and a
maximum total length of MAX_LENGTH. The default value of N is set to match
the currently loaded architecture. The PATTERN argument can be a GDB symbol
(such as a register name), a string or a hexadecimal value"""
_cmdline_ = "pattern search"
_syntax_ = f"{_cmdline_} [-h] [-n N] [--max-length MAX_LENGTH] [pattern]"
_example_ = [f"{_cmdline_} $pc",
f"{_cmdline_} 0x61616164",
f"{_cmdline_} aaab"]
_aliases_ = ["pattern offset"]
@only_if_gdb_running
@parse_arguments({"pattern": ""}, {("--period", "-n"): 0, ("--max-length", "-l"): 0})
def do_invoke(self, _: List[str], **kwargs: Any) -> None:
args = kwargs["arguments"]
if not args.pattern:
warn("No pattern provided")
return
max_length = args.max_length or gef.config["pattern.length"]
n = args.period or gef.arch.ptrsize
if n not in (2, 4, 8) or n > gef.arch.ptrsize:
err("Incorrect value for period")
return
self.search(args.pattern, max_length, n)
return
def search(self, pattern: str, size: int, period: int) -> None:
pattern_be, pattern_le = None, None
# 1. check if it's a symbol (like "$sp" or "0x1337")
symbol = safe_parse_and_eval(pattern)
if symbol:
addr = int(abs(symbol))
dereferenced_value = dereference(addr)
if dereferenced_value:
addr = int(abs(dereferenced_value))
mask = (1<<(8 * period))-1
addr &= mask
pattern_le = addr.to_bytes(period, 'little')
pattern_be = addr.to_bytes(period, 'big')
else:
# 2. assume it's a plain string
pattern_be = gef_pybytes(pattern)
pattern_le = gef_pybytes(pattern[::-1])
info(f"Searching for '{pattern_le.hex()}'/'{pattern_be.hex()}' with period={period}")
cyclic_pattern = generate_cyclic_pattern(size, period)
off = cyclic_pattern.find(pattern_le)
if off >= 0:
ok(f"Found at offset {off:d} (little-endian search) "
f"{Color.colorify('likely', 'bold red') if gef.arch.endianness == Endianness.LITTLE_ENDIAN else ''}")
return
off = cyclic_pattern.find(pattern_be)
if off >= 0:
ok(f"Found at offset {off:d} (big-endian search) "
f"{Color.colorify('likely', 'bold green') if gef.arch.endianness == Endianness.BIG_ENDIAN else ''}")
return
err(f"Pattern '{pattern}' not found")
return
@register
class ChecksecCommand(GenericCommand):
"""Checksec the security properties of the current executable or passed as argument. The
command checks for the following protections:
- PIE
- NX
- RelRO
- Glibc Stack Canaries
- Fortify Source"""
_cmdline_ = "checksec"
_syntax_ = f"{_cmdline_} [FILENAME]"
_example_ = f"{_cmdline_} /bin/ls"
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_FILENAME)
return
def do_invoke(self, argv: List[str]) -> None:
argc = len(argv)
if argc == 0:
filename = get_filepath()
if filename is None:
warn("No executable/library specified")
return
elif argc == 1:
filename = os.path.realpath(os.path.expanduser(argv[0]))
if not os.access(filename, os.R_OK):
err("Invalid filename")
return
else:
self.usage()
return
info(f"{self._cmdline_} for '{filename}'")
self.print_security_properties(filename)
return
def print_security_properties(self, filename: str) -> None:
sec = Elf(filename).checksec
for prop in sec:
if prop in ("Partial RelRO", "Full RelRO"): continue
val = sec[prop]
msg = Color.greenify(Color.boldify(TICK)) if val is True else Color.redify(Color.boldify(CROSS))
if val and prop == "Canary" and is_alive():
canary = gef.session.canary[0] if gef.session.canary else 0
msg += f"(value: {canary:#x})"
gef_print(f"{prop:<30s}: {msg}")
if sec["Full RelRO"]:
gef_print(f"{'RelRO':<30s}: {Color.greenify('Full')}")
elif sec["Partial RelRO"]:
gef_print(f"{'RelRO':<30s}: {Color.yellowify('Partial')}")
else:
gef_print(f"{'RelRO':<30s}: {Color.redify(Color.boldify(CROSS))}")
return
@register
class GotCommand(GenericCommand):
"""Display current status of the got inside the process."""
_cmdline_ = "got"
_syntax_ = f"{_cmdline_} [FUNCTION_NAME ...] "
_example_ = "got read printf exit"
def __init__(self):
super().__init__()
self["function_resolved"] = ("green",
"Line color of the got command output for resolved function")
self["function_not_resolved"] = ("yellow",
"Line color of the got command output for unresolved function")
return
@only_if_gdb_running
def do_invoke(self, argv: List[str]) -> None:
readelf = gef.session.constants["readelf"]
if is_remote_debug():
elf_file = str(gef.session.remote.lfile)
elf_virtual_path = str(gef.session.remote.file)
else:
elf_file = str(gef.session.file)
elf_virtual_path = str(gef.session.file)
func_names_filter = argv if argv else []
vmmap = gef.memory.maps
base_address = min(x.page_start for x in vmmap if x.path == elf_virtual_path)
end_address = max(x.page_end for x in vmmap if x.path == elf_virtual_path)
# get the checksec output.
checksec_status = Elf(elf_file).checksec
relro_status = "Full RelRO"
full_relro = checksec_status["Full RelRO"]
pie = checksec_status["PIE"] # if pie we will have offset instead of abs address.
if not full_relro:
relro_status = "Partial RelRO"
partial_relro = checksec_status["Partial RelRO"]
if not partial_relro:
relro_status = "No RelRO"
# retrieve jump slots using readelf
lines = gef_execute_external([readelf, "--relocs", elf_file], as_list=True)
jmpslots = [line for line in lines if "JUMP" in line]
gef_print(f"\nGOT protection: {relro_status} | GOT functions: {len(jmpslots)}\n ")
for line in jmpslots:
address, _, _, _, name = line.split()[:5]
# if we have a filter let's skip the entries that are not requested.
if func_names_filter:
if not any(map(lambda x: x in name, func_names_filter)):
continue
address_val = int(address, 16)
# address_val is an offset from the base_address if we have PIE.
if pie or is_remote_debug():
address_val = base_address + address_val
# read the address of the function.
got_address = gef.memory.read_integer(address_val)
# for the swag: different colors if the function has been resolved or not.
if base_address < got_address < end_address:
color = self["function_not_resolved"]
else:
color = self["function_resolved"]
line = f"[{hex(address_val)}] "
line += Color.colorify(f"{name} {RIGHT_ARROW} {hex(got_address)}", color)
gef_print(line)
return
@register
class HighlightCommand(GenericCommand):
"""Highlight user-defined text matches in GEF output universally."""
_cmdline_ = "highlight"
_syntax_ = f"{_cmdline_} (add|remove|list|clear)"
_aliases_ = ["hl"]
def __init__(self) -> None:
super().__init__(prefix=True)
self["regex"] = (False, "Enable regex highlighting")
def do_invoke(self, _: List[str]) -> None:
return self.usage()
@register
class HighlightListCommand(GenericCommand):
"""Show the current highlight table with matches to colors."""
_cmdline_ = "highlight list"
_aliases_ = ["highlight ls", "hll"]
_syntax_ = _cmdline_
def print_highlight_table(self) -> None:
if not gef.ui.highlight_table:
err("no matches found")
return
left_pad = max(map(len, gef.ui.highlight_table.keys()))
for match, color in sorted(gef.ui.highlight_table.items()):
print(f"{Color.colorify(match.ljust(left_pad), color)} {VERTICAL_LINE} "
f"{Color.colorify(color, color)}")
return
def do_invoke(self, _: List[str]) -> None:
return self.print_highlight_table()
@register
class HighlightClearCommand(GenericCommand):
"""Clear the highlight table, remove all matches."""
_cmdline_ = "highlight clear"
_aliases_ = ["hlc"]
_syntax_ = _cmdline_
def do_invoke(self, _: List[str]) -> None:
return gef.ui.highlight_table.clear()
@register
class HighlightAddCommand(GenericCommand):
"""Add a match to the highlight table."""
_cmdline_ = "highlight add"
_syntax_ = f"{_cmdline_} MATCH COLOR"
_aliases_ = ["highlight set", "hla"]
_example_ = f"{_cmdline_} 41414141 yellow"
def do_invoke(self, argv: List[str]) -> None:
if len(argv) < 2:
return self.usage()
match, color = argv
gef.ui.highlight_table[match] = color
return
@register
class HighlightRemoveCommand(GenericCommand):
"""Remove a match in the highlight table."""
_cmdline_ = "highlight remove"
_syntax_ = f"{_cmdline_} MATCH"
_aliases_ = [
"highlight delete",
"highlight del",
"highlight unset",
"highlight rm",
"hlr",
]
_example_ = f"{_cmdline_} remove 41414141"
def do_invoke(self, argv: List[str]) -> None:
if not argv:
return self.usage()
gef.ui.highlight_table.pop(argv[0], None)
return
@register
class FormatStringSearchCommand(GenericCommand):
"""Exploitable format-string helper: this command will set up specific breakpoints
at well-known dangerous functions (printf, snprintf, etc.), and check if the pointer
holding the format string is writable, and therefore susceptible to format string
attacks if an attacker can control its content."""
_cmdline_ = "format-string-helper"
_syntax_ = _cmdline_
_aliases_ = ["fmtstr-helper",]
def do_invoke(self, _: List[str]) -> None:
dangerous_functions = {
"printf": 0,
"sprintf": 1,
"fprintf": 1,
"snprintf": 2,
"vsnprintf": 2,
}
nb_installed_breaks = 0
with RedirectOutputContext(to="/dev/null"):
for function_name in dangerous_functions:
argument_number = dangerous_functions[function_name]
FormatStringBreakpoint(function_name, argument_number)
nb_installed_breaks += 1
ok(f"Enabled {nb_installed_breaks} FormatString "
f"breakpoint{'s' if nb_installed_breaks > 1 else ''}")
return
@register
class HeapAnalysisCommand(GenericCommand):
"""Heap vulnerability analysis helper: this command aims to track dynamic heap allocation
done through malloc()/free() to provide some insights on possible heap vulnerabilities. The
following vulnerabilities are checked:
- NULL free
- Use-after-Free
- Double Free
- Heap overlap"""
_cmdline_ = "heap-analysis-helper"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__(complete=gdb.COMPLETE_NONE)
self["check_free_null"] = (False, "Break execution when a free(NULL) is encountered")
self["check_double_free"] = (True, "Break execution when a double free is encountered")
self["check_weird_free"] = (True, "Break execution when free() is called against a non-tracked pointer")
self["check_uaf"] = (True, "Break execution when a possible Use-after-Free condition is found")
self["check_heap_overlap"] = (True, "Break execution when a possible overlap in allocation is found")
self.bp_malloc = None
self.bp_calloc = None
self.bp_free = None
self.bp_realloc = None
return
@only_if_gdb_running
@experimental_feature
def do_invoke(self, argv: List[str]) -> None:
if not argv:
self.setup()
return
if argv[0] == "show":
self.dump_tracked_allocations()
return
def setup(self) -> None:
ok("Tracking malloc() & calloc()")
self.bp_malloc = TraceMallocBreakpoint("__libc_malloc")
self.bp_calloc = TraceMallocBreakpoint("__libc_calloc")
ok("Tracking free()")
self.bp_free = TraceFreeBreakpoint()
ok("Tracking realloc()")
self.bp_realloc = TraceReallocBreakpoint()
ok("Disabling hardware watchpoints (this may increase the latency)")
gdb.execute("set can-use-hw-watchpoints 0")
info("Dynamic breakpoints correctly setup, "
"GEF will break execution if a possible vulnerabity is found.")
warn(f"{Color.colorify('Note', 'bold underline yellow')}: "
"The heap analysis slows down the execution noticeably.")
# when inferior quits, we need to clean everything for a next execution
gef_on_exit_hook(self.clean)
return
def dump_tracked_allocations(self) -> None:
global gef
if gef.session.heap_allocated_chunks:
ok("Tracked as in-use chunks:")
for addr, sz in gef.session.heap_allocated_chunks:
gef_print(f"{CROSS} malloc({sz:d}) = {addr:#x}")
else:
ok("No malloc() chunk tracked")
if gef.session.heap_freed_chunks:
ok("Tracked as free-ed chunks:")
for addr, sz in gef.session.heap_freed_chunks:
gef_print(f"{TICK} free({sz:d}) = {addr:#x}")
else:
ok("No free() chunk tracked")
return
def clean(self, _: "gdb.Event") -> None:
global gef
ok(f"{Color.colorify('Heap-Analysis', 'yellow bold')} - Cleaning up")
for bp in [self.bp_malloc, self.bp_calloc, self.bp_free, self.bp_realloc]:
if hasattr(bp, "retbp") and bp.retbp:
try:
bp.retbp.delete()
except RuntimeError:
# in some cases, gdb was found failing to correctly remove the retbp
# but they can be safely ignored since the debugging session is over
pass
bp.delete()
for wp in gef.session.heap_uaf_watchpoints:
wp.delete()
gef.session.heap_allocated_chunks = []
gef.session.heap_freed_chunks = []
gef.session.heap_uaf_watchpoints = []
ok(f"{Color.colorify('Heap-Analysis', 'yellow bold')} - Re-enabling hardware watchpoints")
gdb.execute("set can-use-hw-watchpoints 1")
gef_on_exit_unhook(self.clean)
return
#
# GDB Function declaration
#
@deprecated("")
def register_function(cls: Type["GenericFunction"]) -> Type["GenericFunction"]:
"""Decorator for registering a new convenience function to GDB."""
return cls
class GenericFunction(gdb.Function):
"""This is an abstract class for invoking convenience functions, should not be instantiated."""
_function_ : str
_syntax_: str = ""
_example_ : str = ""
def __init__(self) -> None:
super().__init__(self._function_)
def invoke(self, *args: Any) -> int:
if not is_alive():
raise gdb.GdbError("No debugging session active")
return self.do_invoke(args)
def arg_to_long(self, args: List, index: int, default: int = 0) -> int:
try:
addr = args[index]
return int(addr) if addr.address is None else int(addr.address)
except IndexError:
return default
def do_invoke(self, args: Any) -> int:
raise NotImplementedError
@register
class StackOffsetFunction(GenericFunction):
"""Return the current stack base address plus an optional offset."""
_function_ = "_stack"
_syntax_ = f"${_function_}()"
def do_invoke(self, args: List) -> int:
base = get_section_base_address("[stack]")
if not base:
raise gdb.GdbError("Stack not found")
return self.arg_to_long(args, 0) + base
@register
class HeapBaseFunction(GenericFunction):
"""Return the current heap base address plus an optional offset."""
_function_ = "_heap"
_syntax_ = f"${_function_}()"
def do_invoke(self, args: List) -> int:
base = gef.heap.base_address
if not base:
base = get_section_base_address("[heap]")
if not base:
raise gdb.GdbError("Heap not found")
return self.arg_to_long(args, 0) + base
@register
class SectionBaseFunction(GenericFunction):
"""Return the matching file's base address plus an optional offset.
Defaults to current file. Note that quotes need to be escaped"""
_function_ = "_base"
_syntax_ = "$_base([filepath])"
_example_ = "p $_base(\\\"/usr/lib/ld-2.33.so\\\")"
def do_invoke(self, args: List) -> int:
addr = 0
try:
name = args[0].string()
except IndexError:
name = gef.session.file.name
except gdb.error:
err(f"Invalid arg: {args[0]}")
return 0
try:
base = get_section_base_address(name)
if base:
addr = int(base)
except TypeError:
err(f"Cannot find section {name}")
return 0
return addr
@register
class BssBaseFunction(GenericFunction):
"""Return the current bss base address plus the given offset."""
_function_ = "_bss"
_syntax_ = f"${_function_}([OFFSET])"
_example_ = "deref $_bss(0x20)"
def do_invoke(self, args: List) -> int:
base = get_zone_base_address(".bss")
if not base:
raise gdb.GdbError("BSS not found")
return self.arg_to_long(args, 0) + base
@register
class GotBaseFunction(GenericFunction):
"""Return the current GOT base address plus the given offset."""
_function_ = "_got"
_syntax_ = f"${_function_}([OFFSET])"
_example_ = "deref $_got(0x20)"
def do_invoke(self, args: List) -> int:
base = get_zone_base_address(".got")
if not base:
raise gdb.GdbError("GOT not found")
return base + self.arg_to_long(args, 0)
@register
class GefFunctionsCommand(GenericCommand):
"""List the convenience functions provided by GEF."""
_cmdline_ = "functions"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__()
self.docs = []
self.should_refresh = True
return
def __add__(self, function: GenericFunction):
"""Add function to documentation."""
doc = getattr(function, "__doc__", "").lstrip()
if not hasattr(function, "_syntax_"):
raise ValueError("Function is invalid")
syntax = getattr(function, "_syntax_").lstrip()
msg = f"{Color.colorify(syntax, 'bold cyan')}\n {doc}"
example = getattr(function, "_example_", "").strip()
if example:
msg += f"\n {Color.yellowify('Example:')} {example}"
self.docs.append(msg)
return self
def __radd__(self, function: GenericFunction):
return self.__add__(function)
def __str__(self) -> str:
if self.should_refresh:
self.__rebuild()
return self.__doc__ or ""
def __rebuild(self) -> None:
"""Rebuild the documentation for functions."""
for function in gef.gdb.functions.values():
self += function
self.command_size = len(gef.gdb.commands)
_, cols = get_terminal_size()
separator = HORIZONTAL_LINE*cols
self.__doc__ = f"\n{separator}\n".join(sorted(self.docs))
self.should_refresh = False
return
def do_invoke(self, argv) -> None:
self.dont_repeat()
gef_print(titlify("GEF - Convenience Functions"))
gef_print("These functions can be used as arguments to other "
"commands to dynamically calculate values\n")
gef_print(str(self))
return
#
# GEF internal command classes
#
class GefCommand(gdb.Command):
"""GEF main command: view all new commands by typing `gef`."""
_cmdline_ = "gef"
_syntax_ = f"{_cmdline_} (missing|config|save|restore|set|run)"
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, True)
gef.config["gef.follow_child"] = GefSetting(True, bool, "Automatically set GDB to follow child when forking")
gef.config["gef.readline_compat"] = GefSetting(False, bool, "Workaround for readline SOH/ETX issue (SEGV)")
gef.config["gef.debug"] = GefSetting(False, bool, "Enable debug mode for gef")
gef.config["gef.autosave_breakpoints_file"] = GefSetting("", str, "Automatically save and restore breakpoints")
gef.config["gef.extra_plugins_dir"] = GefSetting("", str, "Autoload additional GEF commands from external directory", hooks={"on_write": self.load_extra_plugins})
gef.config["gef.disable_color"] = GefSetting(False, bool, "Disable all colors in GEF")
gef.config["gef.tempdir"] = GefSetting(GEF_TEMP_DIR, str, "Directory to use for temporary/cache content")
gef.config["gef.show_deprecation_warnings"] = GefSetting(True, bool, "Toggle the display of the `deprecated` warnings")
gef.config["gef.buffer"] = GefSetting(True, bool, "Internally buffer command output until completion")
gef.config["gef.bruteforce_main_arena"] = GefSetting(False, bool, "Allow bruteforcing main_arena symbol if everything else fails")
gef.config["gef.main_arena_offset"] = GefSetting("", str, "Offset from libc base address to main_arena symbol (int or hex). Set to empty string to disable.")
self.commands : Dict[str, GenericCommand] = collections.OrderedDict()
self.functions : Dict[str, GenericFunction] = collections.OrderedDict()
self.missing: Dict[str, Exception] = {}
return
@property
def loaded_commands(self) -> List[Tuple[str, Type[GenericCommand], Any]]:
print("Obsolete loaded_commands")
raise
@property
def loaded_functions(self) -> List[Type[GenericFunction]]:
print("Obsolete loaded_functions")
raise
@property
def missing_commands(self) -> Dict[str, Exception]:
print("Obsolete missing_commands")
raise
def setup(self) -> None:
self.load()
GefHelpCommand()
GefConfigCommand()
GefSaveCommand()
GefMissingCommand()
GefSetCommand()
GefRunCommand()
GefInstallExtraScriptCommand()
# restore the settings from config file if any
GefRestoreCommand()
return
def load_extra_plugins(self) -> int:
def load_plugin(fpath: pathlib.Path) -> bool:
try:
dbg(f"Loading '{fpath}'")
gdb.execute(f"source {fpath}")
except Exception as e:
warn(f"Exception while loading {fpath}: {str(e)}")
return False
return True
nb_added = -1
start_time = time.perf_counter()
try:
nb_inital = len(__registered_commands__)
directories: List[str] = gef.config["gef.extra_plugins_dir"].split(";") or []
for d in directories:
d = d.strip()
if not d: continue
directory = pathlib.Path(d).expanduser()
if not directory.is_dir(): continue
sys.path.append(str(directory.absolute()))
for entry in directory.iterdir():
if entry.is_dir():
if entry.name in ('gdb', 'gef', '__pycache__'): continue
load_plugin(entry / "__init__.py")
else:
if entry.suffix != ".py": continue
if entry.name == "__init__.py": continue
load_plugin(entry)
nb_added = len(__registered_commands__) - nb_inital
if nb_added > 0:
self.load()
nb_failed = len(__registered_commands__) - len(self.commands)
end_time = time.perf_counter()
load_time = end_time - start_time
ok(f"{Color.colorify(str(nb_added), 'bold green')} extra commands added from "
f"'{Color.colorify(', '.join(directories), 'bold blue')}' in {load_time:.2f} seconds")
if nb_failed != 0:
warn(f"{Color.colorify(str(nb_failed), 'bold light_gray')} extra commands/functions failed to be added. "
"Check `gef missing` to know why")
except gdb.error as e:
err(f"failed: {e}")
return nb_added
@property
def loaded_command_names(self) -> Iterable[str]:
print("obsolete loaded_command_names")
return self.commands.keys()
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
gdb.execute("gef help")
return
def add_context_pane(self, pane_name: str, display_pane_function: Callable, pane_title_function: Callable, condition: Optional[Callable]) -> None:
"""Add a new context pane to ContextCommand."""
for _, class_instance in self.commands.items():
if isinstance(class_instance, ContextCommand):
context = class_instance
break
else:
err("Cannot find ContextCommand")
return
# assure users can toggle the new context
corrected_settings_name = pane_name.replace(" ", "_")
gef.config["context.layout"] += f" {corrected_settings_name}"
# overload the printing of pane title
context.layout_mapping[corrected_settings_name] = (display_pane_function, pane_title_function, condition)
def load(self) -> None:
"""Load all the commands and functions defined by GEF into GDB."""
current_commands = set( self.commands.keys() )
new_commands = set( [x._cmdline_ for x in __registered_commands__] ) - current_commands
current_functions = set( self.functions.keys() )
new_functions = set([x._function_ for x in __registered_functions__]) - current_functions
self.missing.clear()
self.__load_time_ms = time.time()* 1000
# load all new functions
for name in sorted(new_functions):
for function_cls in __registered_functions__:
if function_cls._function_ == name:
self.functions[name] = function_cls()
break
# load all new commands
for name in sorted(new_commands):
try:
for command_cls in __registered_commands__:
if command_cls._cmdline_ == name:
command_instance = command_cls()
# create the aliases if any
if hasattr(command_instance, "_aliases_"):
aliases = getattr(command_instance, "_aliases_")
for alias in aliases:
GefAlias(alias, name)
self.commands[name] = command_instance
break
except Exception as reason:
self.missing[name] = reason
self.__load_time_ms = (time.time()* 1000) - self.__load_time_ms
return
def show_banner(self) -> None:
gef_print(f"{Color.greenify('GEF')} for {gef.session.os} ready, "
f"type `{Color.colorify('gef', 'underline yellow')}' to start, "
f"`{Color.colorify('gef config', 'underline pink')}' to configure")
ver = f"{sys.version_info.major:d}.{sys.version_info.minor:d}"
gef_print(f"{Color.colorify(str(len(self.commands)), 'bold green')} commands loaded "
f"and {Color.colorify(str(len(self.functions)), 'bold blue')} functions added for "
f"GDB {Color.colorify(gdb.VERSION, 'bold yellow')} in {self.__load_time_ms:.2f}ms "
f"using Python engine {Color.colorify(ver, 'bold red')}")
nb_missing = len(self.missing)
if nb_missing:
warn(f"{Color.colorify(str(nb_missing), 'bold red')} "
f"command{'s' if nb_missing > 1 else ''} could not be loaded, "
f"run `{Color.colorify('gef missing', 'underline pink')}` to know why.")
return
class GefHelpCommand(gdb.Command):
"""GEF help sub-command."""
_cmdline_ = "gef help"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, False)
self.docs = []
self.should_refresh = True
self.command_size = 0
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
gef_print(titlify("GEF - GDB Enhanced Features"))
gef_print(str(self))
return
def __rebuild(self) -> None:
"""Rebuild the documentation."""
for name, cmd in gef.gdb.commands.items():
self += (name, cmd)
self.command_size = len(gef.gdb.commands)
_, cols = get_terminal_size()
separator = HORIZONTAL_LINE*cols
self.__doc__ = f"\n{separator}\n".join(sorted(self.docs))
self.should_refresh = False
return
def __add__(self, command: Tuple[str, GenericCommand]):
"""Add command to GEF documentation."""
cmd, class_obj = command
if " " in cmd:
# do not print subcommands in gef help
return self
doc = getattr(class_obj, "__doc__", "").lstrip()
aliases = f"Aliases: {', '.join(class_obj._aliases_)}" if hasattr(class_obj, "_aliases_") else ""
msg = f"{Color.colorify(cmd, 'bold red')}\n{doc}\n{aliases}"
self.docs.append(msg)
return self
def __radd__(self, command: Tuple[str, GenericCommand]):
return self.__add__(command)
def __str__(self) -> str:
"""Lazily regenerate the `gef help` object if it was modified"""
# quick check in case the docs have changed
if self.should_refresh or self.command_size != len(gef.gdb.commands):
self.__rebuild()
return self.__doc__ or ""
class GefConfigCommand(gdb.Command):
"""GEF configuration sub-command
This command will help set/view GEF settings for the current debugging session.
It is possible to make those changes permanent by running `gef save` (refer
to this command help), and/or restore previously saved settings by running
`gef restore` (refer help).
"""
_cmdline_ = "gef config"
_syntax_ = f"{_cmdline_} [setting_name] [setting_value]"
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_NONE, prefix=False)
return
def invoke(self, args: str, from_tty: bool) -> None:
self.dont_repeat()
argv = gdb.string_to_argv(args)
argc = len(argv)
if not (0 <= argc <= 2):
err("Invalid number of arguments")
return
if argc == 0:
gef_print(titlify("GEF configuration settings"))
self.print_settings()
return
if argc == 1:
prefix = argv[0]
names = [x for x in gef.config.keys() if x.startswith(prefix)]
if names:
if len(names) == 1:
gef_print(titlify(f"GEF configuration setting: {names[0]}"))
self.print_setting(names[0], verbose=True)
else:
gef_print(titlify(f"GEF configuration settings matching '{argv[0]}'"))
for name in names: self.print_setting(name)
return
self.set_setting(argv)
return
def print_setting(self, plugin_name: str, verbose: bool = False) -> None:
res = gef.config.raw_entry(plugin_name)
string_color = gef.config["theme.dereference_string"]
misc_color = gef.config["theme.dereference_base_address"]
if not res:
return
_setting = Color.colorify(plugin_name, "green")
_type = res.type.__name__
if _type == "str":
_value = f'"{Color.colorify(res.value, string_color)}"'
else:
_value = Color.colorify(res.value, misc_color)
gef_print(f"{_setting} ({_type}) = {_value}")
if verbose:
gef_print(Color.colorify("\nDescription:", "bold underline"))
gef_print(f"\t{res.description}")
return
def print_settings(self) -> None:
for x in sorted(gef.config):
self.print_setting(x)
return
def set_setting(self, argv: Tuple[str, Any]) -> None:
global gef
key, new_value = argv
if "." not in key:
err("Invalid command format")
return
loaded_commands = list( gef.gdb.commands.keys()) + ["gef"]
plugin_name = key.split(".", 1)[0]
if plugin_name not in loaded_commands:
err(f"Unknown plugin '{plugin_name}'")
return
if key not in gef.config:
err(f"'{key}' is not a valid configuration setting")
return
_type = gef.config.raw_entry(key).type
try:
if _type == bool:
_newval = True if new_value.upper() in ("TRUE", "T", "1") else False
else:
_newval = new_value
gef.config[key] = _newval
except Exception as e:
err(f"'{key}' expects type '{_type.__name__}', got {type(new_value).__name__}: reason {str(e)}")
return
reset_all_caches()
return
def complete(self, text: str, word: str) -> List[str]:
settings = sorted(gef.config)
if text == "":
# no prefix: example: `gef config TAB`
return [s for s in settings if word in s]
if "." not in text:
# if looking for possible prefix
return [s for s in settings if s.startswith(text.strip())]
# finally, look for possible values for given prefix
return [s.split(".", 1)[1] for s in settings if s.startswith(text.strip())]
class GefSaveCommand(gdb.Command):
"""GEF save sub-command.
Saves the current configuration of GEF to disk (by default in file '~/.gef.rc')."""
_cmdline_ = "gef save"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, False)
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
cfg = configparser.RawConfigParser()
old_sect = None
# save the configuration
for key in sorted(gef.config):
sect, optname = key.split(".", 1)
value = gef.config[key]
if old_sect != sect:
cfg.add_section(sect)
old_sect = sect
cfg.set(sect, optname, value)
# save the aliases
cfg.add_section("aliases")
for alias in gef.session.aliases:
cfg.set("aliases", alias._alias, alias._command)
with GEF_RC.open("w") as fd:
cfg.write(fd)
ok(f"Configuration saved to '{GEF_RC}'")
return
class GefRestoreCommand(gdb.Command):
"""GEF restore sub-command.
Loads settings from file '~/.gef.rc' and apply them to the configuration of GEF."""
_cmdline_ = "gef restore"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, False)
self.reload(True)
return
def invoke(self, args: str, from_tty: bool) -> None:
self.dont_repeat()
if GEF_RC.is_file():
quiet = (args.lower() == "quiet")
self.reload(quiet)
return
def reload(self, quiet: bool):
cfg = configparser.ConfigParser()
cfg.read(GEF_RC)
for section in cfg.sections():
if section == "aliases":
# load the aliases
for key in cfg.options(section):
try:
GefAlias(key, cfg.get(section, key))
except:
pass
continue
# load the other options
for optname in cfg.options(section):
key = f"{section}.{optname}"
try:
setting = gef.config.raw_entry(key)
except Exception:
continue
new_value = cfg.get(section, optname)
if setting.type == bool:
new_value = True if new_value.upper() in ("TRUE", "T", "1") else False
setting.value = setting.type(new_value)
if not quiet:
ok(f"Configuration from '{Color.colorify(str(GEF_RC), 'bold blue')}' restored")
return
class GefMissingCommand(gdb.Command):
"""GEF missing sub-command
Display the GEF commands that could not be loaded, along with the reason of why
they could not be loaded.
"""
_cmdline_ = "gef missing"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, False)
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
missing_commands = gef.gdb.missing
if not missing_commands:
ok("No missing command")
return
for missing_command, reason in missing_commands.items():
warn(f"Command `{missing_command}` is missing, reason {RIGHT_ARROW} {reason}")
return
class GefSetCommand(gdb.Command):
"""Override GDB set commands with the context from GEF."""
_cmdline_ = "gef set"
_syntax_ = f"{_cmdline_} [GDB_SET_ARGUMENTS]"
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_SYMBOL, False)
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
args = args.split()
cmd = ["set", args[0],]
for p in args[1:]:
if p.startswith("$_gef"):
c = gdb.parse_and_eval(p)
cmd.append(c.string())
else:
cmd.append(p)
gdb.execute(" ".join(cmd))
return
class GefRunCommand(gdb.Command):
"""Override GDB run commands with the context from GEF.
Simple wrapper for GDB run command to use arguments set from `gef set args`."""
_cmdline_ = "gef run"
_syntax_ = f"{_cmdline_} [GDB_RUN_ARGUMENTS]"
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_FILENAME, False)
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
if is_alive():
gdb.execute("continue")
return
argv = args.split()
gdb.execute(f"gef set args {' '.join(argv)}")
gdb.execute("run")
return
class GefAlias(gdb.Command):
"""Simple aliasing wrapper because GDB doesn't do what it should."""
def __init__(self, alias: str, command: str, completer_class: int = gdb.COMPLETE_NONE, command_class: int = gdb.COMMAND_NONE) -> None:
p = command.split()
if not p:
return
if any(x for x in gef.session.aliases if x._alias == alias):
return
self._command = command
self._alias = alias
c = command.split()[0]
r = self.lookup_command(c)
self.__doc__ = f"Alias for '{Color.greenify(command)}'"
if r is not None:
_instance = r[1]
self.__doc__ += f": {_instance.__doc__}"
if hasattr(_instance, "complete"):
self.complete = _instance.complete
super().__init__(alias, command_class, completer_class=completer_class)
gef.session.aliases.append(self)
return
def invoke(self, args: Any, from_tty: bool) -> None:
gdb.execute(f"{self._command} {args}", from_tty=from_tty)
return
def lookup_command(self, cmd: str) -> Optional[Tuple[str, GenericCommand]]:
global gef
for _name, _instance in gef.gdb.commands.items():
if cmd == _name:
return _name, _instance
return None
@register
class AliasesCommand(GenericCommand):
"""Base command to add, remove, or list aliases."""
_cmdline_ = "aliases"
_syntax_ = f"{_cmdline_} (add|rm|ls)"
def __init__(self) -> None:
super().__init__(prefix=True)
return
def do_invoke(self, _: List[str]) -> None:
self.usage()
return
@register
class AliasesAddCommand(AliasesCommand):
"""Command to add aliases."""
_cmdline_ = "aliases add"
_syntax_ = f"{_cmdline_} [ALIAS] [COMMAND]"
_example_ = f"{_cmdline_} scope telescope"
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, argv: List[str]) -> None:
if len(argv) < 2:
self.usage()
return
GefAlias(argv[0], " ".join(argv[1:]))
return
@register
class AliasesRmCommand(AliasesCommand):
"""Command to remove aliases."""
_cmdline_ = "aliases rm"
_syntax_ = f"{_cmdline_} [ALIAS]"
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, argv: List[str]) -> None:
global gef
if len(argv) != 1:
self.usage()
return
try:
alias_to_remove = next(filter(lambda x: x._alias == argv[0], gef.session.aliases))
gef.session.aliases.remove(alias_to_remove)
except (ValueError, StopIteration):
err(f"{argv[0]} not found in aliases.")
return
gef_print("You must reload GEF for alias removals to apply.")
return
@register
class AliasesListCommand(AliasesCommand):
"""Command to list aliases."""
_cmdline_ = "aliases ls"
_syntax_ = _cmdline_
def __init__(self) -> None:
super().__init__()
return
def do_invoke(self, _: List[str]) -> None:
ok("Aliases defined:")
for a in gef.session.aliases:
gef_print(f"{a._alias:30s} {RIGHT_ARROW} {a._command}")
return
class GefTmuxSetup(gdb.Command):
"""Setup a confortable tmux debugging environment."""
def __init__(self) -> None:
super().__init__("tmux-setup", gdb.COMMAND_NONE, gdb.COMPLETE_NONE)
GefAlias("screen-setup", "tmux-setup")
return
def invoke(self, args: Any, from_tty: bool) -> None:
self.dont_repeat()
tmux = os.getenv("TMUX")
if tmux:
self.tmux_setup()
return
screen = os.getenv("TERM")
if screen is not None and screen == "screen":
self.screen_setup()
return
warn("Not in a tmux/screen session")
return
def tmux_setup(self) -> None:
"""Prepare the tmux environment by vertically splitting the current pane, and
forcing the context to be redirected there."""
tmux = which("tmux")
ok("tmux session found, splitting window...")
pane, pty = subprocess.check_output([tmux, "splitw", "-h", '-F#{session_name}:#{window_index}.#{pane_index}-#{pane_tty}', "-P"]).decode().strip().split("-")
atexit.register(lambda : subprocess.run([tmux, "kill-pane", "-t", pane]))
# clear the screen and let it wait for input forever
gdb.execute(f"! {tmux} send-keys -t {pane} 'clear ; cat' C-m")
gdb.execute(f"! {tmux} select-pane -L")
ok(f"Setting `context.redirect` to '{pty}'...")
gdb.execute(f"gef config context.redirect {pty}")
ok("Done!")
return
def screen_setup(self) -> None:
"""Hackish equivalent of the tmux_setup() function for screen."""
screen = which("screen")
sty = os.getenv("STY")
ok("screen session found, splitting window...")
fd_script, script_path = tempfile.mkstemp()
fd_tty, tty_path = tempfile.mkstemp()
os.close(fd_tty)
with os.fdopen(fd_script, "w") as f:
f.write("startup_message off\n")
f.write("split -v\n")
f.write("focus right\n")
f.write(f"screen bash -c 'tty > {tty_path}; clear; cat'\n")
f.write("focus left\n")
gdb.execute(f"! {screen} -r {sty} -m -d -X source {script_path}")
# artificial delay to make sure `tty_path` is populated
time.sleep(0.25)
with open(tty_path, "r") as f:
pty = f.read().strip()
ok(f"Setting `context.redirect` to '{pty}'...")
gdb.execute(f"gef config context.redirect {pty}")
ok("Done!")
os.unlink(script_path)
os.unlink(tty_path)
return
class GefInstallExtraScriptCommand(gdb.Command):
"""`gef install` command: installs one or more scripts from the `gef-extras` script repo. Note that the command
doesn't check for external dependencies the script(s) might require."""
_cmdline_ = "gef install"
_syntax_ = f"{_cmdline_} SCRIPTNAME [SCRIPTNAME [SCRIPTNAME...]]"
def __init__(self) -> None:
super().__init__(self._cmdline_, gdb.COMMAND_SUPPORT, gdb.COMPLETE_NONE, False)
self.branch = gef.config.get("gef.extras_default_branch", GEF_EXTRAS_DEFAULT_BRANCH)
return
def invoke(self, argv: str, from_tty: bool) -> None:
self.dont_repeat()
if not argv:
err("No script name provided")
return
args = argv.split()
if "--list" in args or "-l" in args:
subprocess.run(["xdg-open", f"https://github.com/hugsy/gef-extras/{self.branch}/"])
return
self.dirpath = pathlib.Path(gef.config["gef.tempdir"]).expanduser().absolute()
if not self.dirpath.is_dir():
err("'gef.tempdir' is not a valid directory")
return
for script in args:
script = script.lower()
if not self.__install_extras_script(script):
warn(f"Failed to install '{script}', skipping...")
return
def __install_extras_script(self, script: str) -> bool:
fpath = self.dirpath / f"{script}.py"
if not fpath.exists():
url = f"https://raw.githubusercontent.com/hugsy/gef-extras/{self.branch}/scripts/{script}.py"
info(f"Searching for '{script}.py' in `gef-extras@{self.branch}`...")
data = http_get(url)
if not data:
warn("Not found")
return False
with fpath.open("wb") as fd:
fd.write(data)
fd.flush()
old_command_set = set(gef.gdb.commands)
gdb.execute(f"source {fpath}")
new_command_set = set(gef.gdb.commands)
new_commands = [f"`{c[0]}`" for c in (new_command_set - old_command_set)]
ok(f"Installed file '{fpath}', new command(s) available: {', '.join(new_commands)}")
return True
#
# GEF internal classes
#
def __gef_prompt__(current_prompt: Callable[[Callable], str]) -> str:
"""GEF custom prompt function."""
if gef.config["gef.readline_compat"] is True: return GEF_PROMPT
if gef.config["gef.disable_color"] is True: return GEF_PROMPT
prompt = ""
if gef.session.remote:
prompt += Color.boldify("(remote) ")
prompt += GEF_PROMPT_ON if is_alive() else GEF_PROMPT_OFF
return prompt
class GefManager(metaclass=abc.ABCMeta):
def reset_caches(self) -> None:
"""Reset the LRU-cached attributes"""
for attr in dir(self):
try:
obj = getattr(self, attr)
if not hasattr(obj, "cache_clear"):
continue
obj.cache_clear()
except: # we're reseting the cache here, we don't care if (or which) exception triggers
continue
return
class GefMemoryManager(GefManager):
"""Class that manages memory access for gef."""
def __init__(self) -> None:
self.reset_caches()
return
def reset_caches(self) -> None:
super().reset_caches()
self.__maps = None
return
def write(self, address: int, buffer: ByteString, length: int = 0x10) -> None:
"""Write `buffer` at address `address`."""
gdb.selected_inferior().write_memory(address, buffer, length)
def read(self, addr: int, length: int = 0x10) -> bytes:
"""Return a `length` long byte array with the copy of the process memory at `addr`."""
return gdb.selected_inferior().read_memory(addr, length).tobytes()
def read_integer(self, addr: int) -> int:
"""Return an integer read from memory."""
sz = gef.arch.ptrsize
mem = self.read(addr, sz)
unpack = u32 if sz == 4 else u64
return unpack(mem)
def read_cstring(self,
address: int,
max_length: int = GEF_MAX_STRING_LENGTH,
encoding: Optional[str] = None) -> str:
"""Return a C-string read from memory."""
encoding = encoding or "unicode-escape"
length = min(address | (DEFAULT_PAGE_SIZE-1), max_length+1)
try:
res_bytes = self.read(address, length)
except gdb.error:
err(f"Can't read memory at '{address}'")
return ""
try:
with warnings.catch_warnings():
# ignore DeprecationWarnings (see #735)
warnings.simplefilter("ignore")
res = res_bytes.decode(encoding, "strict")
except UnicodeDecodeError:
# latin-1 as fallback due to its single-byte to glyph mapping
res = res_bytes.decode("latin-1", "replace")
res = res.split("\x00", 1)[0]
ustr = res.replace("\n", "\\n").replace("\r", "\\r").replace("\t", "\\t")
if max_length and len(res) > max_length:
return f"{ustr[:max_length]}[...]"
return ustr
def read_ascii_string(self, address: int) -> Optional[str]:
"""Read an ASCII string from memory"""
cstr = self.read_cstring(address)
if isinstance(cstr, str) and cstr and all(x in string.printable for x in cstr):
return cstr
return None
@property
def maps(self) -> List[Section]:
if not self.__maps:
self.__maps = self.__parse_maps()
return self.__maps
def __parse_maps(self) -> List[Section]:
"""Return the mapped memory sections"""
try:
if is_qemu_system():
return list(self.__parse_info_mem())
except gdb.error:
# Target may not support this command
pass
try:
return list(self.__parse_procfs_maps())
except FileNotFoundError:
return list(self.__parse_gdb_info_sections())
def __parse_procfs_maps(self) -> Generator[Section, None, None]:
"""Get the memory mapping from procfs."""
procfs_mapfile = gef.session.maps
if not procfs_mapfile:
is_remote = gef.session.remote is not None
raise FileNotFoundError(f"Missing {'remote ' if is_remote else ''}procfs map file")
with procfs_mapfile.open("r") as fd:
for line in fd:
line = line.strip()
addr, perm, off, _, rest = line.split(" ", 4)
rest = rest.split(" ", 1)
if len(rest) == 1:
inode = rest[0]
pathname = ""
else:
inode = rest[0]
pathname = rest[1].lstrip()
addr_start, addr_end = parse_string_range(addr)
off = int(off, 16)
perm = Permission.from_process_maps(perm)
inode = int(inode)
yield Section(page_start=addr_start,
page_end=addr_end,
offset=off,
permission=perm,
inode=inode,
path=pathname)
return
def __parse_gdb_info_sections(self) -> Generator[Section, None, None]:
"""Get the memory mapping from GDB's command `maintenance info sections` (limited info)."""
stream = StringIO(gdb.execute("maintenance info sections", to_string=True))
for line in stream:
if not line:
break
try:
parts = [x for x in line.split()]
addr_start, addr_end = [int(x, 16) for x in parts[1].split("->")]
off = int(parts[3][:-1], 16)
path = parts[4]
perm = Permission.from_info_sections(parts[5:])
yield Section(
page_start=addr_start,
page_end=addr_end,
offset=off,
permission=perm,
inode="",
path=path
)
except IndexError:
continue
except ValueError:
continue
return
def __parse_info_mem(self) -> Generator[Section, None, None]:
"""Get the memory mapping from GDB's command `monitor info mem`"""
for line in StringIO(gdb.execute("monitor info mem", to_string=True)):
if not line:
break
try:
ranges, off, perms = line.split()
off = int(off, 16)
start, end = [int(s, 16) for s in ranges.split("-")]
except ValueError as e:
continue
perm = Permission.from_info_mem(perms)
yield Section(
page_start=start,
page_end=end,
offset=off,
permission=perm,
inode="",
)
class GefHeapManager(GefManager):
"""Class managing session heap."""
def __init__(self) -> None:
self.reset_caches()
return
def reset_caches(self) -> None:
self.__libc_main_arena: Optional[GlibcArena] = None
self.__libc_selected_arena: Optional[GlibcArena] = None
self.__heap_base = None
return
@property
def main_arena(self) -> Optional[GlibcArena]:
if not self.__libc_main_arena:
try:
__main_arena_addr = GefHeapManager.find_main_arena_addr()
self.__libc_main_arena = GlibcArena(f"*{__main_arena_addr:#x}")
# the initialization of `main_arena` also defined `selected_arena`, so
# by default, `main_arena` == `selected_arena`
self.selected_arena = self.__libc_main_arena
except:
# the search for arena can fail when the session is not started
pass
return self.__libc_main_arena
@main_arena.setter
def main_arena(self, value: GlibcArena) -> None:
self.__libc_main_arena = value
return
@staticmethod
@lru_cache()
def find_main_arena_addr() -> int:
"""A helper function to find the glibc `main_arena` address, either from
symbol, from its offset from `__malloc_hook` or by brute force."""
# Before anything else, use libc offset from config if available
if gef.config["gef.main_arena_offset"]:
try:
libc_base = get_section_base_address("libc")
offset = parse_address(gef.config["gef.main_arena_offset"])
if libc_base:
dbg(f"Using main_arena_offset={offset:#x} from config")
addr = libc_base + offset
# Verify the found address before returning
if GlibcArena.verify(addr):
return addr
except gdb.error:
pass
# First, try to find `main_arena` symbol directly
try:
return parse_address(f"&{LIBC_HEAP_MAIN_ARENA_DEFAULT_NAME}")
except gdb.error:
pass
# Second, try to find it by offset from `__malloc_hook`
if gef.libc.version < (2, 34):
try:
malloc_hook_addr = parse_address("(void *)&__malloc_hook")
struct_size = ctypes.sizeof(GlibcArena.malloc_state_t())
if is_x86():
addr = align_address_to_size(malloc_hook_addr + gef.arch.ptrsize, 0x20)
elif is_arch(Elf.Abi.AARCH64):
addr = malloc_hook_addr - gef.arch.ptrsize*2 - struct_size
elif is_arch(Elf.Abi.ARM):
addr = malloc_hook_addr - gef.arch.ptrsize - struct_size
else:
addr = None
# Verify the found address before returning
if addr and GlibcArena.verify(addr):
return addr
except gdb.error:
pass
# Last resort, try to find it via brute force if enabled in settings
if gef.config["gef.bruteforce_main_arena"]:
alignment = 0x8
try:
dbg("Trying to bruteforce main_arena address")
# setup search_range for `main_arena` to `.data` of glibc
search_filter = lambda f: "libc" in f.filename and f.name == ".data"
dotdata = list(filter(search_filter, get_info_files()))[0]
search_range = range(dotdata.zone_start, dotdata.zone_end, alignment)
# find first possible candidate
for addr in search_range:
if GlibcArena.verify(addr):
dbg(f"Found candidate at {addr:#x}")
return addr
dbg("Bruteforce not successful")
except Exception:
pass
# Nothing helped
err_msg = f"Cannot find main_arena for {gef.arch.arch}. You might want to set a manually found libc offset "
if not gef.config["gef.bruteforce_main_arena"]:
err_msg += "or allow bruteforcing "
err_msg += "through the GEF config."
raise OSError(err_msg)
@property
def selected_arena(self) -> Optional[GlibcArena]:
if not self.__libc_selected_arena:
# `selected_arena` must default to `main_arena`
self.__libc_selected_arena = self.main_arena
return self.__libc_selected_arena
@selected_arena.setter
def selected_arena(self, value: GlibcArena) -> None:
self.__libc_selected_arena = value
return
@property
def arenas(self) -> Union[List, Iterator[GlibcArena]]:
if not self.main_arena:
return []
return iter(self.main_arena)
@property
def base_address(self) -> Optional[int]:
if not self.__heap_base:
base = 0
try:
base = parse_address("mp_->sbrk_base")
base = self.malloc_align_address(base)
except gdb.error:
# missing symbol, try again
base = 0
if not base:
base = get_section_base_address("[heap]")
self.__heap_base = base
return self.__heap_base
@property
def chunks(self) -> Union[List, Iterator]:
if not self.base_address:
return []
return iter(GlibcChunk(self.base_address, from_base=True))
@property
def min_chunk_size(self) -> int:
return 4 * gef.arch.ptrsize
@property
def malloc_alignment(self) -> int:
__default_malloc_alignment = 0x10
if gef.libc.version >= (2, 26) and is_x86_32():
# Special case introduced in Glibc 2.26:
# https://elixir.bootlin.com/glibc/glibc-2.26/source/sysdeps/i386/malloc-alignment.h#L22
return __default_malloc_alignment
# Generic case:
# https://elixir.bootlin.com/glibc/glibc-2.26/source/sysdeps/generic/malloc-alignment.h#L22
return 2 * gef.arch.ptrsize
def csize2tidx(self, size: int) -> int:
return abs((size - self.min_chunk_size + self.malloc_alignment - 1)) // self.malloc_alignment
def tidx2size(self, idx: int) -> int:
return idx * self.malloc_alignment + self.min_chunk_size
def malloc_align_address(self, address: int) -> int:
"""Align addresses according to glibc's MALLOC_ALIGNMENT. See also Issue #689 on Github"""
malloc_alignment = self.malloc_alignment
ceil = lambda n: int(-1 * n // 1 * -1)
return malloc_alignment * ceil((address / malloc_alignment))
class GefSetting:
"""Basic class for storing gef settings as objects"""
READ_ACCESS = 0
WRITE_ACCESS = 1
def __init__(self, value: Any, cls: Optional[type] = None, description: Optional[str] = None, hooks: Optional[Dict[str, Callable]] = None) -> None:
self.value = value
self.type = cls or type(value)
self.description = description or ""
self.hooks: Tuple[List[Callable], List[Callable]] = ([], [])
if hooks:
for access, func in hooks.items():
if access == "on_read":
idx = GefSetting.READ_ACCESS
elif access == "on_write":
idx = GefSetting.WRITE_ACCESS
else:
raise ValueError
if not callable(func):
raise ValueError(f"hook is not callable")
self.hooks[idx].append(func)
return
def __str__(self) -> str:
return f"Setting(type={self.type.__name__}, value='{self.value}', desc='{self.description[:10]}...', "\
f"read_hooks={len(self.hooks[GefSetting.READ_ACCESS])}, write_hooks={len(self.hooks[GefSetting.READ_ACCESS])})"
class GefSettingsManager(dict):
"""
GefSettings acts as a dict where the global settings are stored and can be read, written or deleted as any other dict.
For instance, to read a specific command setting: `gef.config[mycommand.mysetting]`
"""
def __getitem__(self, name: str) -> Any:
setting : GefSetting = super().__getitem__(name)
self.__invoke_read_hooks(setting)
return setting.value
def __setitem__(self, name: str, value: Any) -> None:
# check if the key exists
if super().__contains__(name):
# if so, update its value directly
setting = super().__getitem__(name)
if not isinstance(setting, GefSetting): raise ValueError
setting.value = setting.type(value)
else:
# if not, `value` must be a GefSetting
if not isinstance(value, GefSetting): raise Exception("Invalid argument")
if not value.type: raise Exception("Invalid type")
if not value.description: raise Exception("Invalid description")
setting = value
super().__setitem__(name, setting)
self.__invoke_write_hooks(setting)
return
def __delitem__(self, name: str) -> None:
super().__delitem__(name)
return
def raw_entry(self, name: str) -> GefSetting:
return super().__getitem__(name)
def __invoke_read_hooks(self, setting: GefSetting) -> None:
self.__invoke_hooks(is_write=False, setting=setting)
return
def __invoke_write_hooks(self, setting: GefSetting) -> None:
self.__invoke_hooks(is_write=True, setting=setting)
return
def __invoke_hooks(self, is_write: bool, setting: GefSetting) -> None:
if not setting.hooks:
return
idx = int(is_write)
if setting.hooks[idx]:
for callback in setting.hooks[idx]:
callback()
return
class GefSessionManager(GefManager):
"""Class managing the runtime properties of GEF. """
def __init__(self) -> None:
self.reset_caches()
self.remote: Optional["GefRemoteSessionManager"] = None
self.remote_initializing: bool = False
self.qemu_mode: bool = False
self.convenience_vars_index: int = 0
self.heap_allocated_chunks: List[Tuple[int, int]] = []
self.heap_freed_chunks: List[Tuple[int, int]] = []
self.heap_uaf_watchpoints: List[UafWatchpoint] = []
self.pie_breakpoints: Dict[int, PieVirtualBreakpoint] = {}
self.pie_counter: int = 1
self.aliases: List[GefAlias] = []
self.modules: List[FileFormat] = []
self.constants = {} # a dict for runtime constants (like 3rd party file paths)
for constant in ("python3", "readelf", "file", "ps"):
self.constants[constant] = which(constant)
return
def reset_caches(self) -> None:
super().reset_caches()
self._auxiliary_vector = None
self._pagesize = None
self._os = None
self._pid = None
self._file = None
self._maps: Optional[pathlib.Path] = None
self._root: Optional[pathlib.Path] = None
return
def __str__(self) -> str:
return f"Session({'Local' if self.remote is None else 'Remote'}, pid={self.pid or 'Not running'}, os='{self.os}')"
@property
def auxiliary_vector(self) -> Optional[Dict[str, int]]:
if not is_alive():
return None
if is_qemu_system():
return None
if not self._auxiliary_vector:
auxiliary_vector = {}
auxv_info = gdb.execute("info auxv", to_string=True)
if not auxv_info or "failed" in auxv_info:
err("Failed to query auxiliary variables")
return None
for line in auxv_info.splitlines():
line = line.split('"')[0].strip() # remove the ending string (if any)
line = line.split() # split the string by whitespace(s)
if len(line) < 4:
continue
__av_type = line[1]
__av_value = line[-1]
auxiliary_vector[__av_type] = int(__av_value, base=0)
self._auxiliary_vector = auxiliary_vector
return self._auxiliary_vector
@property
def os(self) -> str:
"""Return the current OS."""
if not self._os:
self._os = platform.system().lower()
return self._os
@property
def pid(self) -> int:
"""Return the PID of the target process."""
if not self._pid:
pid = gdb.selected_inferior().pid if not gef.session.qemu_mode else gdb.selected_thread().ptid[1]
if not pid:
raise RuntimeError("cannot retrieve PID for target process")
self._pid = pid
return self._pid
@property
def file(self) -> Optional[pathlib.Path]:
"""Return a Path object of the target process."""
if gef.session.remote is not None:
return gef.session.remote.file
fpath: str = gdb.current_progspace().filename
if fpath and not self._file:
self._file = pathlib.Path(fpath).expanduser()
return self._file
@property
def cwd(self) -> Optional[pathlib.Path]:
if gef.session.remote is not None:
return gef.session.remote.root
return self.file.parent if self.file else None
@property
def pagesize(self) -> int:
"""Get the system page size"""
auxval = self.auxiliary_vector
if not auxval:
return DEFAULT_PAGE_SIZE
self._pagesize = auxval["AT_PAGESZ"]
return self._pagesize
@property
def canary(self) -> Optional[Tuple[int, int]]:
"""Return a tuple of the canary address and value, read from the canonical
location if supported by the architecture. Otherwise, read from the auxiliary
vector."""
try:
canary_location = gef.arch.canary_address()
canary = gef.memory.read_integer(canary_location)
except NotImplementedError:
# Fall back to `AT_RANDOM`, which is the original source
# of the canary value but not the canonical location
return self.original_canary
return canary, canary_location
@property
def original_canary(self) -> Optional[Tuple[int, int]]:
"""Return a tuple of the initial canary address and value, read from the
auxiliary vector."""
auxval = self.auxiliary_vector
if not auxval:
return None
canary_location = auxval["AT_RANDOM"]
canary = gef.memory.read_integer(canary_location)
canary &= ~0xFF
return canary, canary_location
@property
def maps(self) -> Optional[pathlib.Path]:
"""Returns the Path to the procfs entry for the memory mapping."""
if not is_alive():
return None
if not self._maps:
if gef.session.remote is not None:
self._maps = gef.session.remote.maps
else:
self._maps = pathlib.Path(f"/proc/{self.pid}/maps")
return self._maps
@property
def root(self) -> Optional[pathlib.Path]:
"""Returns the path to the process's root directory."""
if not is_alive():
return None
if not self._root:
self._root = pathlib.Path(f"/proc/{self.pid}/root")
return self._root
class GefRemoteSessionManager(GefSessionManager):
"""Class for managing remote sessions with GEF. It will create a temporary environment
designed to clone the remote one."""
def __init__(self, host: str, port: int, pid: int =-1, qemu: Optional[pathlib.Path] = None) -> None:
super().__init__()
self.__host = host
self.__port = port
self.__local_root_fd = tempfile.TemporaryDirectory()
self.__local_root_path = pathlib.Path(self.__local_root_fd.name)
self.__qemu = qemu
dbg(f"[remote] initializing remote session with {self.target} under {self.root}")
if not self.connect(pid):
raise EnvironmentError(f"Cannot connect to remote target {self.target}")
if not self.setup():
raise EnvironmentError(f"Failed to create a proper environment for {self.target}")
return
def close(self) -> None:
self.__local_root_fd.cleanup()
try:
gef_on_new_unhook(self.remote_objfile_event_handler)
gef_on_new_hook(new_objfile_handler)
except Exception as e:
warn(f"Exception while restoring local context: {str(e)}")
return
def in_qemu_user(self) -> bool:
return self.__qemu is not None
def __str__(self) -> str:
return f"RemoteSession(target='{self.target}', local='{self.root}', pid={self.pid}, qemu_user={bool(self.in_qemu_user())})"
@property
def target(self) -> str:
return f"{self.__host}:{self.__port}"
@property
def root(self) -> pathlib.Path:
return self.__local_root_path.absolute()
@property
def file(self) -> pathlib.Path:
"""Path to the file being debugged as seen by the remote endpoint."""
if not self._file:
filename = gdb.current_progspace().filename
if not filename:
raise RuntimeError("No session started")
start_idx = len("target:") if filename.startswith("target:") else 0
self._file = pathlib.Path(filename[start_idx:])
return self._file
@property
def lfile(self) -> pathlib.Path:
"""Local path to the file being debugged."""
return self.root / str(self.file).lstrip("/")
@property
def maps(self) -> pathlib.Path:
if not self._maps:
self._maps = self.root / f"proc/{self.pid}/maps"
return self._maps
def sync(self, src: str, dst: Optional[str] = None) -> bool:
"""Copy the `src` into the temporary chroot. If `dst` is provided, that path will be
used instead of `src`."""
if not dst:
dst = src
tgt = self.root / dst.lstrip("/")
if tgt.exists():
return True
tgt.parent.mkdir(parents=True, exist_ok=True)
dbg(f"[remote] downloading '{src}' -> '{tgt}'")
gdb.execute(f"remote get {src} {tgt.absolute()}")
return tgt.exists()
def connect(self, pid: int) -> bool:
"""Connect to remote target. If in extended mode, also attach to the given PID."""
# before anything, register our new hook to download files from the remote target
dbg(f"[remote] Installing new objfile handlers")
gef_on_new_unhook(new_objfile_handler)
gef_on_new_hook(self.remote_objfile_event_handler)
# then attempt to connect
is_extended_mode = (pid > -1)
dbg(f"[remote] Enabling extended remote: {bool(is_extended_mode)}")
try:
with DisableContextOutputContext():
cmd = f"target {'extended-' if is_extended_mode else ''}remote {self.target}"
dbg(f"[remote] Executing '{cmd}'")
gdb.execute(cmd)
if is_extended_mode:
gdb.execute(f"attach {pid:d}")
return True
except Exception as e:
err(f"Failed to connect to {self.target}: {e}")
# a failure will trigger the cleanup, deleting our hook anyway
return False
def setup(self) -> bool:
# setup remote adequately depending on remote or qemu mode
if self.in_qemu_user():
dbg(f"Setting up as qemu session, target={self.__qemu}")
self.__setup_qemu()
else:
dbg(f"Setting up as remote session")
self.__setup_remote()
# refresh gef to consider the binary
reset_all_caches()
gef.binary = Elf(self.lfile)
reset_architecture()
return True
def __setup_qemu(self) -> bool:
# setup emulated file in the chroot
assert self.__qemu
target = self.root / str(self.__qemu.parent).lstrip("/")
target.mkdir(parents=True, exist_ok=False)
shutil.copy2(self.__qemu, target)
self._file = self.__qemu
assert self.lfile.exists()
# create a procfs
procfs = self.root / f"proc/{self.pid}/"
procfs.mkdir(parents=True, exist_ok=True)
## /proc/pid/cmdline
cmdline = procfs / "cmdline"
if not cmdline.exists():
with cmdline.open("w") as fd:
fd.write("")
## /proc/pid/environ
environ = procfs / "environ"
if not environ.exists():
with environ.open("wb") as fd:
fd.write(b"PATH=/bin\x00HOME=/tmp\x00")
## /proc/pid/maps
maps = procfs / "maps"
if not maps.exists():
with maps.open("w") as fd:
fname = self.file.absolute()
mem_range = "00000000-ffffffff" if is_32bit() else "0000000000000000-ffffffffffffffff"
fd.write(f"{mem_range} rwxp 00000000 00:00 0 {fname}\n")
return True
def __setup_remote(self) -> bool:
# get the file
fpath = f"/proc/{self.pid}/exe"
if not self.sync(fpath, str(self.file)):
err(f"'{fpath}' could not be fetched on the remote system.")
return False
# pseudo procfs
for _file in ("maps", "environ", "cmdline"):
fpath = f"/proc/{self.pid}/{_file}"
if not self.sync(fpath):
err(f"'{fpath}' could not be fetched on the remote system.")
return False
# makeup a fake mem mapping in case we failed to retrieve it
maps = self.root / f"proc/{self.pid}/maps"
if not maps.exists():
with maps.open("w") as fd:
fname = self.file.absolute()
mem_range = "00000000-ffffffff" if is_32bit() else "0000000000000000-ffffffffffffffff"
fd.write(f"{mem_range} rwxp 00000000 00:00 0 {fname}\n")
return True
def remote_objfile_event_handler(self, evt: "gdb.NewObjFileEvent") -> None:
dbg(f"[remote] in remote_objfile_handler({evt.new_objfile.filename if evt else 'None'}))")
if not evt or not evt.new_objfile.filename:
return
if not evt.new_objfile.filename.startswith("target:") and not evt.new_objfile.filename.startswith("/"):
warn(f"[remote] skipping '{evt.new_objfile.filename}'")
return
if evt.new_objfile.filename.startswith("target:"):
src: str = evt.new_objfile.filename[len("target:"):]
if not self.sync(src):
raise FileNotFoundError(f"Failed to sync '{src}'")
return
class GefUiManager(GefManager):
"""Class managing UI settings."""
def __init__(self) -> None:
self.redirect_fd : Optional[TextIOWrapper] = None
self.context_hidden = False
self.stream_buffer : Optional[StringIO] = None
self.highlight_table: Dict[str, str] = {}
self.watches: Dict[int, Tuple[int, str]] = {}
self.context_messages: List[Tuple[str, str]] = []
return
class GefLibcManager(GefManager):
"""Class managing everything libc-related (except heap)."""
def __init__(self) -> None:
self._version : Optional[Tuple[int, int]] = None
return
def __str__(self) -> str:
return f"Libc(version='{self.version}')"
@property
def version(self) -> Optional[Tuple[int, int]]:
if not is_alive():
return None
if not self._version:
self._version = GefLibcManager.find_libc_version()
return self._version
@staticmethod
@lru_cache()
def find_libc_version() -> Tuple[int, ...]:
sections = gef.memory.maps
for section in sections:
match = re.search(r"libc6?[-_](\d+)\.(\d+)\.so", section.path)
if match:
return tuple(int(_) for _ in match.groups())
if "libc" in section.path:
try:
with open(section.path, "rb") as f:
data = f.read()
except OSError:
continue
match = re.search(PATTERN_LIBC_VERSION, data)
if match:
return tuple(int(_) for _ in match.groups())
return 0, 0
class Gef:
"""The GEF root class, which serves as a entrypoint for all the debugging session attributes (architecture,
memory, settings, etc.)."""
binary: Optional[FileFormat]
arch: Architecture
config : GefSettingsManager
ui: GefUiManager
libc: GefLibcManager
memory : GefMemoryManager
heap : GefHeapManager
session : GefSessionManager
gdb: GefCommand
def __init__(self) -> None:
self.binary: Optional[FileFormat] = None
self.arch: Architecture = GenericArchitecture() # see PR #516, will be reset by `new_objfile_handler`
self.config = GefSettingsManager()
self.ui = GefUiManager()
self.libc = GefLibcManager()
return
def __str__(self) -> str:
return f"Gef(binary='{self.binary or 'None'}', arch={self.arch})"
def reinitialize_managers(self) -> None:
"""Reinitialize the managers. Avoid calling this function directly, using `pi reset()` is preferred"""
self.memory = GefMemoryManager()
self.heap = GefHeapManager()
self.session = GefSessionManager()
return
def setup(self) -> None:
"""Setup initialize the runtime setup, which may require for the `gef` to be not None."""
self.reinitialize_managers()
self.gdb = GefCommand()
self.gdb.setup()
tempdir = self.config["gef.tempdir"]
gef_makedirs(tempdir)
gdb.execute(f"save gdb-index {tempdir}")
return
def reset_caches(self) -> None:
"""Recursively clean the cache of all the managers. Avoid calling this function directly, using `reset-cache`
is preferred"""
for mgr in (self.memory, self.heap, self.session, self.arch):
mgr.reset_caches()
return
if __name__ == "__main__":
if sys.version_info[0] == 2:
err("GEF has dropped Python2 support for GDB when it reached EOL on 2020/01/01.")
err("If you require GEF for GDB+Python2, use https://github.com/hugsy/gef-legacy.")
exit(1)
if GDB_VERSION < GDB_MIN_VERSION or PYTHON_VERSION < PYTHON_MIN_VERSION:
err("You're using an old version of GDB. GEF will not work correctly. "
f"Consider updating to GDB {'.'.join(map(str, GDB_MIN_VERSION))} or higher "
f"(with Python {'.'.join(map(str, PYTHON_MIN_VERSION))} or higher).")
exit(1)
try:
pyenv = which("pyenv")
PYENV_ROOT = gef_pystring(subprocess.check_output([pyenv, "root"]).strip())
PYENV_VERSION = gef_pystring(subprocess.check_output([pyenv, "version-name"]).strip())
site_packages_dir = os.path.join(PYENV_ROOT, "versions", PYENV_VERSION, "lib",
f"python{PYENV_VERSION[:3]}", "site-packages")
site.addsitedir(site_packages_dir)
except FileNotFoundError:
pass
# When using a Python virtual environment, GDB still loads the system-installed Python
# so GEF doesn't load site-packages dir from environment
# In order to fix it, from the shell with venv activated we run the python binary,
# take and parse its path, add the path to the current python process using sys.path.extend
PYTHONBIN = which("python3")
PREFIX = gef_pystring(subprocess.check_output([PYTHONBIN, '-c', 'import os, sys;print((sys.prefix))'])).strip("\\n")
if PREFIX != sys.base_prefix:
SITE_PACKAGES_DIRS = subprocess.check_output(
[PYTHONBIN, "-c", "import os, sys;print(os.linesep.join(sys.path).strip())"]).decode("utf-8").split()
sys.path.extend(SITE_PACKAGES_DIRS)
# setup config
gdb_initial_settings = (
"set confirm off",
"set verbose off",
"set pagination off",
"set print elements 0",
"set history save on",
f"set history filename {os.getenv('GDBHISTFILE', '~/.gdb_history')}",
"set output-radix 0x10",
"set print pretty on",
"set disassembly-flavor intel",
"handle SIGALRM print nopass",
)
for cmd in gdb_initial_settings:
try:
gdb.execute(cmd)
except gdb.error:
pass
# load GEF, set up the managers and load the plugins, functions,
reset()
gef.gdb.load()
gef.gdb.show_banner()
# load config
gef.gdb.load_extra_plugins()
# setup gdb prompt
gdb.prompt_hook = __gef_prompt__
# gdb events configuration
gef_on_continue_hook(continue_handler)
gef_on_stop_hook(hook_stop_handler)
gef_on_new_hook(new_objfile_handler)
gef_on_exit_hook(exit_handler)
gef_on_memchanged_hook(memchanged_handler)
gef_on_regchanged_hook(regchanged_handler)
if gdb.current_progspace().filename is not None:
# if here, we are sourcing gef from a gdb session already attached, force call to new_objfile (see issue #278)
new_objfile_handler(None)
GefTmuxSetup()
# `target remote` commands cannot be disabled, so print a warning message instead
errmsg = "Using `target remote` with GEF does not work, use `gef-remote` instead. You've been warned."
gdb.execute(f"define target hook-remote\n pi if calling_function() != \"connect\": err(\"{errmsg}\") \nend")
gdb.execute(f"define target hook-extended-remote\n pi if calling_function() != \"connect\": err(\"{errmsg}\") \nend")