43 lines
1.0 KiB
Markdown
43 lines
1.0 KiB
Markdown
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# Integral Promotion
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* Conditions of data types with different max and min values provoke unforseen comparisions
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* Comparing `int` and `uint` with values above max leads to integral promotion
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* Check data type min and max
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```c
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#include <stdio.h>
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#include <limits.h>
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int main(void)
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{
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printf("CHAR_MAX: %i\n", CHAR_MAX);
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printf("UCHAR_MAX: %i\n", UCHAR_MAX);
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printf("SHORT_MAX: %i\n", SHRT_MAX);
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printf("USHORT_MAX: %i\n", USHRT_MAX);
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printf("INT_MAX: %i\n", INT_MAX);
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printf("UINT_MAX: %u\n", UINT_MAX);
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return 0;
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}
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```
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* Not only conditions are susceptable to integral promotions, a sum - for example - is too. Values for promotion in this example are `2147483647` and `1`. `c` is negative and leads to the shell
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```c
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int a,b,c;
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if(a >=0 && b >=0)
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if(c >= 0){
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printf("\n[*] ADDING %d + %d",a,b);
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printf("\n[*] RESULT: %d\n",c);
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}
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else{
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system("/bin/sh");
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}
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else
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printf("nope");
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```
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