通过注入的 DLL 绕过成员函数

Question

原帖：

我试图从我注入的 DLL 中绕过一个成员函数。 我已经获得了我试图挂钩的函数的地址，但无法弄清楚通过 detours 库挂钩它的正确语法或方法。 我已经评论了给我错误消息的行。

我已经阅读了成员函数挂钩的 detours 示例的源代码，这就是此代码所基于的内容，但由于某种原因它不起作用。

任何帮助将不胜感激，谢谢！

#include <windows.h>
#include <detours.h>

class CDetour
{
public:
    bool My_MemFn(unsigned int unk1);
    static bool (CDetour::* Real_MemFn)(unsigned int);
};

bool CDetour::My_MemFn(unsigned int unk1)
{
        /* do stuff here */
    return (this->*Real_MemFn)(unk1);
}

typedef bool (CDetour::* MemFn_t)(unsigned int unk1);

MemFn_t CDetour::Real_MemFn= *(MemFn_t *)((void*)0x23234545);

BOOL APIENTRY DllMain(HANDLE hModule, DWORD dwReason, LPVOID lpReserved)
{
    switch (dwReason)
    {
        case DLL_PROCESS_ATTACH:
        {
            DetourTransactionBegin();
            DetourUpdateThread(GetCurrentThread());
            DetourAttach(&(PVOID&)CDetour::Real_MemFn, *(PBYTE*)&CDetour::My_MemFn); // ERROR: C2440: 'type cast' : cannot convert from 'bool __thiscall CDetour::* )(unsigned int)' to 'PBYTE *'
            DetourTransactionCommit();
            break;
        }
    }

    return TRUE;
}

解决方案：

#include <windows.h>
#include <detours.h>

typedef void (__thiscall * CClassFunction_t)(void *__this, unsigned int unk1);
CClassFunction_t Real_CClassFunction;

void __fastcall Mine_CClassFunction(void *__this, int edx, unsigned int unk1)
{
    Real_CClassFunction(__this, unk1);
}

template<typename T>
void HookFunction(const char *module, char *signature, T &fn_real, PVOID fn_mine)
{
    HookFunction<T>(DetourFindFunction(module, signature), fn_real, fn_mine);
}

template<typename T>
void HookFunction(DWORD address, T &fn_real, PVOID fn_mine)
{
    HookFunction<T>(reinterpret_cast<PVOID>(address), fn_real, fn_mine);
}

template<typename T>
void HookFunction(PVOID target, T &fn_real, PVOID fn_mine)
{
    fn_real = reinterpret_cast<T>(target);

    HookFunction<T>(fn_real, fn_mine);
}

template<typename T>
void HookFunction(T &fn_real, PVOID fn_mine)
{
    DetourAttach(&(PVOID&)fn_real, fn_mine);
}


void ApplyHooks()
{
    DetourTransactionBegin();
    DetourUpdateThread(GetCurrentThread());

    DWORD function_address = 0x12345678;

    HookFunction<CClassFunction_t>(address, Real_CClassFunction, Mine_CClassFunction);

    DetourTransactionCommit();
}

BOOL APIENTRY DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)
{
    switch (dwReason)
    {
        case DLL_PROCESS_ATTACH:
        case DLL_THREAD_ATTACH:
        {
            DisableThreadLibraryCalls(hInstance);

            CreateThread(0, 0, (LPTHREAD_START_ROUTINE)ApplyHooks, 0, 0, 0);

            break;
        }
    }

    return TRUE;
}

Answer 1

经过数小时的搜索并试图找到解决方案，我想出了这个不错的小解决方案：

#include <windows.h>
#include <detours.h>

typedef void (__thiscall * CClassFunction_t)(void *__this, unsigned int unk1);
CClassFunction_t Real_CClassFunction;

void __fastcall Mine_CClassFunction(void *__this, int edx, unsigned int unk1)
{
    Real_CClassFunction(__this, unk1);
}

template<typename T>
void HookFunction(const char *module, char *signature, T &fn_real, PVOID fn_mine)
{
    HookFunction<T>(DetourFindFunction(module, signature), fn_real, fn_mine);
}

template<typename T>
void HookFunction(DWORD address, T &fn_real, PVOID fn_mine)
{
    HookFunction<T>(reinterpret_cast<PVOID>(address), fn_real, fn_mine);
}

template<typename T>
void HookFunction(PVOID target, T &fn_real, PVOID fn_mine)
{
    fn_real = reinterpret_cast<T>(target);

    HookFunction<T>(fn_real, fn_mine);
}

template<typename T>
void HookFunction(T &fn_real, PVOID fn_mine)
{
    DetourAttach(&(PVOID&)fn_real, fn_mine);
}


void ApplyHooks()
{
    DetourTransactionBegin();
    DetourUpdateThread(GetCurrentThread());

    DWORD function_address = 0x12345678;

    HookFunction<CClassFunction_t>(address, Real_CClassFunction, Mine_CClassFunction);

    DetourTransactionCommit();
}

BOOL APIENTRY DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)
{
    switch (dwReason)
    {
        case DLL_PROCESS_ATTACH:
        case DLL_THREAD_ATTACH:
        {
            DisableThreadLibraryCalls(hInstance);

            CreateThread(0, 0, (LPTHREAD_START_ROUTINE)ApplyHooks, 0, 0, 0);

            break;
        }
    }

    return TRUE;
}

Answer 2

尝试使用：

union {
  bool (CDetour::*lpMyFunction)(unsigned int);
  PBYTE lpAddr;
} u;

将指针保存在u.lpMyFunction并从u.lpAddr

这是否解决了您的编译问题？

Answer 3

是的，我实际上讨厌那些演员表，所以我自己做了：

// Cast a member function pointer that cannot have a reference taken to a void *
template <typename RET_TYPE, typename CLASS, typename...ARGs>
void* castToVoidPtr(RET_TYPE(CLASS::*&&pOriginalFunction)(ARGs...))
{
    union
    {
        RET_TYPE(CLASS::*pMemFn)(ARGs...);
        void* voidPtr;
    } cast = { pOriginalFunction };
    static_assert(sizeof(cast.pMemFn) == sizeof(cast.voidPtr), "Cannot cast this member function pointer to a void*.  Not the same size.");
    return cast.voidPtr;
}

// Cast a member function pointer to a void*&
template <typename RET_TYPE, typename CLASS, typename...ARGs>
void*& castToVoidPtr(RET_TYPE(CLASS::*&pOriginalFunction)(ARGs...))
{
    union
    {
        RET_TYPE(CLASS::*&pMemFn)(ARGs...);
        void*& voidPtr;
    } cast = { pOriginalFunction };
    static_assert(sizeof(cast.pMemFn) == sizeof(cast.voidPtr), "Cannot cast this member function pointer to a void*.  Not the same size.");
    return cast.voidPtr;
}

您的解决方案的唯一问题是您将额外的 DWORD 推入堆栈（EDX 寄存器），这是不必要的。 这些强制转换应该适用于您将使用它的所有情况。从我收集的信息来看，它不适用于多继承类函数，这不是您可能用于绕道的东西，并且如果您要尝试就会断言.

这将允许您执行以下操作：

DetourAttach(&castToVoidPtr(CDetour::Real_MemFn), castToVoidPtr(&CDetour::My_MemFn));

Answer 4

"void* castToVoidPtr(RET_TYPE(CLASS::*&&pOriginalFunction)(ARGs...))"

这 && 正是你想写的吗？ VS2008 编译时报错。