你能帮我理解下面两个组装说明的目的吗?(有关更多上下文,最后是汇编 + C 代码)。谢谢 !
movzx edx,BYTE PTR [edx+0xa]
mov BYTE PTR [eax+0xa],dl
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汇编代码如下:
push ebp
mov ebp,esp
and esp,0xfffffff0
sub esp,0x70
mov eax,gs:0x14
mov DWORD PTR [esp+0x6c],eax
xor eax,eax
mov edx,0x8048520
lea eax,[esp+0x8]
mov ecx,DWORD PTR [edx]
mov DWORD PTR [eax],ecx
mov ecx,DWORD PTR [edx+0x4]
mov DWORD PTR [eax+0x4],ecx
movzx ecx,WORD PTR [edx+0x8]
mov WORD PTR [eax+0x8],cx
movzx edx,BYTE PTR [edx+0xa] ; instruction 1
mov BYTE PTR [eax+0xa],dl ; instruction 2
mov edx,DWORD PTR [esp+0x6c]
xor edx,DWORD PTR gs:0x14
je 804844d <main+0x49>
call 8048320 <__stack_chk_fail@plt>
leave
ret
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下面的 C 源代码(不包含库):
int main() {
char str_a[100];
strcpy(str_a, "eeeeefffff");
}