反汇编:字符串的3种表达方式

时间:2022-04-26 18:52:15

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‘};,反汇编如下

可以发现进行地址处理的时候都是通过ebp来间接赋值的,不需要去依赖任何的东西,只需要有EBP寄存器作为参照物!在shellcode中利用也起到一部分的作用!

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";,反汇编如下

可以明显发现与上面的写法的区别,ABCDEF是存储在内存地址中的!取值的时候是把本身的地址作为参照物!

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";,反汇编如下

跟上面的差不多,都需要自身地址作为支撑,不同的地方是这个是一步到位,会直接格式化字符串然后存储到一个地址中!

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:    }