Disassembly: The three expression string

char str[6] = {'a','b','c','d','e','f'};
char str[] = "ABCDEF";
char *str = "ABCDEF";

1 char str[6] = {'a','b','c','d','e','f'};, following disassembly

The address can be found at all times be treated by ebp indirect assignment , you do not need to rely on any thing, only to have the EBP register as a reference! In the shellcode in the exploit also play the role of a part of!

6:        char str[6] = {'a','b','c','d','e','f'};
00401038   mov         byte ptr [ebp-8],61h
0040103C   mov         byte ptr [ebp-7],62h
00401040   mov         byte ptr [ebp-6],63h
00401044   mov         byte ptr [ebp-5],64h
00401048   mov         byte ptr [ebp-4],65h
0040104C   mov         byte ptr [ebp-3],66h
7:        return 0;
00401050   xor         eax,eax
8:    }

2 char str[] = "ABCDEF";, following disassembly

Can obviously find the difference between the wording of the above, ABCDEFit is stored in the memory address! The value of time is to address itself as a reference!

6:        char str[] = "ABCDEF";
00401038   mov         eax,[string "ABCDEF" (00422fa4)]
0040103D   mov         dword ptr [ebp-8],eax
00401040   mov         cx,word ptr [string "ABCDEF"+4 (00422fa8)]
00401047   mov         word ptr [ebp-4],cx
0040104B   mov         dl,byte ptr [string "ABCDEF"+6 (00422faa)]
00401051   mov         byte ptr [ebp-2],dl
7:        return 0;
00401050   xor         eax,eax
}

3 char *str = "ABCDEF";, following disassembly

Almost with the above, you need to own address as a support, different places that this is one step, directly formatted string is then stored in an address!

5:    int main(){
00401020   push        ebp
00401021   mov         ebp,esp
00401023   sub         esp,44h
00401026   push        ebx
00401027   push        esi
00401028   push        edi
00401029   lea         edi,[ebp-44h]
0040102C   mov         ecx,11h
00401031   mov         eax,0CCCCCCCCh
00401036   rep stos    dword ptr [edi]
6:        char *str = "ABCDEF";  //我在这里!
00401038   mov         dword ptr [ebp-4],offset string "ABCDEF" (00422fa4)
7:        return 0;
0040103F   xor         eax,eax
8:    }

Guess you like

Origin www.cnblogs.com/zpchcbd/p/12339941.html