strstr ShellCode实现

 char* Mystrstr(const char* SrcStrPtr, const char* SubStrPtr)
{
    int nCount;
    if (*SubStrPtr)             //判断寻找的SubStr是否为空.
    {
        while (*SrcStrPtr)      //判断寻找的srcStr是否为空,不为空循环
        {
            //内部循环判断.每次 str指针++ 判断跟 substr++ 是否相等.
            for (nCount = 0; *(SrcStrPtr + nCount) == *(SubStrPtr + nCount); nCount++)

            {
                //如果substrptr + 1 没有.则返回找到的字符串.
                if (!*(SubStrPtr + nCount + 1))
                {
                    return(char*)SrcStrPtr;
                }

            }
            SrcStrPtr++;
        }
        return NULL;
    }
    else
        return (char*)SrcStrPtr;
}

UCHAR g_StrstrShellCode[] =
{
	0X55,
	0X8B,0xEC,
	0X53,
	0X57,
	0X8B,0X7D,0X0C,
	0X8A,0X1F,
	0X84,0XDB,
	0X74,0X3E,
	0X56,
	0X8B,0X75,0X08,
	0X8A,0X06,
	0X84,0XC0,
	0X74,0X26,
	0X8B,0XD6,
	0X2B,0XD7,
	0X0F,0X1F,0X40,0X00,

	0X3A,0XC3,
	0X75,0X11,
	0X8B,0XC7,


	0X8A,0X48,0X01,
	0X8D,0X40,0X01,
	0X84,0XC9,
	0X74,0X15,
	0X38,0X0C,0X02,
	0X74,0XF1,

	0X8A,0X46,0X01,
	0X46,
	0X42,
	0X84,0XC0,
	0X75,0XE2,

	0X5E,
	0X5F,
	0X33,0XC0,
	0X5B,
	0X5D,
	0XC3,

	0x8b,0xc6,
	0x5e,
	0x5f,
	0x5b,
	0x5d,
	0xc3,

	0x8b,0x45,0x08,
	0x5f,
	0x5b,
	0x5d,
	0xc3
};

push    ebp
mov     ebp, esp
push    ebx
push    edi
mov     edi, dword ptr ss:[ebp + 0xC]
mov     bl, byte ptr ds:[edi]
test    bl, bl
je      0x7E004C                              //重定位
push    esi
mov     esi, dword ptr ss:[ebp + 0x8]
mov     al, byte ptr ds:[esi]
test    al, al
je      0x7E003E                              //重定位
mov     edx, esi
sub     edx, edi
nop     dword ptr ds:[eax], eax
cmp     al, bl
jne     0x7E0035                              //重定位
mov     eax, edi
mov     cl, byte ptr ds:[eax + 0x1]
lea     eax, dword ptr ds:[eax + 0x1]
test    cl, cl
je      0x7E0045                             //重定位
cmp     byte ptr ds:[edx + eax], cl
je      0x7E0026                             //重定位
mov     al, byte ptr ds:[esi + 0x1]
inc     esi
inc     edx
test    al, al
jne     0x7E0020                             //重定位
pop     esi
pop     edi
xor     eax, eax
pop     ebx
pop     ebp
ret     
mov     eax, esi
pop     esi
pop     edi
pop     ebx
pop     ebp
ret     
mov     eax, dword ptr ss:[ebp + 0x8]
pop     edi
pop     ebx
pop     ebp
ret     

LPVOID lpShellCodeMemory = VirtualAlloc(NULL, 0x1000, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
memcpy(lpShellCodeMemory, g_StrstrShellCode, 0x200);