Win32,如何用C++挂钩编译程序中的函数？

Question

以此为例(在Ollydbg调试器中查看)

第一个PUSH EBP指令是void*f(int32_t n)的开始(idk它返回的内容,只是猜测void*),我知道输入参数n在堆栈中,并且EBP + 8是指向那个变量,我猜它就像int*n =(int*)(uint32_t(EBP)+ 0x08);/*假设EBP是void*和sizeof(EBP)== sizeof(uint32_t)== sizeof(void*)并且+8数学在c ++ uint32_t和x86程序集中相同..*/

我想制作一个钩子,它将检查n是否大于7或小于0,如果是,则将其更改为1.使用ollydbg,直接编写汇编代码,我可以:修补第一个MOV EBP,对JMP的ESP指令SHORT到它后面的INT3指令(我需要7个字节),然后将(未使用的)INT3更改为MOV EBP,ESP JMP LONG 0068BCCD,其中0068BCCD是文件末尾未使用的0x000000000000的

,然后在0068BCCD,我可以编写汇编代码来检查EBP + 8指向的int,并在必要时修改它:

PUSHAD
CMP DWORD PTR SS:[EBP+8],7
JA SHORT Error
CMP DWORD PTR SS:[EBP+8],0
JL SHORT Error
JMP SHORT Finished
Error:
PUSHAD
PUSH OFFSET TheString
CALL Onlink-x86.App::Output
ADD ESP,4
POPAD
MOV DWORD PTR SS:[EBP+8],1
Finished:
POPAD
JMP LONG 00447493
TheString:
"Warning: label assertion failed, but (pretending its 1 and) trying to ignore.."+0x00

哪个(如果我没有搞砸)基本上相当于

void FilterIntAtEBP_8(){
int i=*(int*)(uint32_t(EBP)+8);
if(i>7 || i<0){
Output("Warning: label assertion failed, but (pretending its 1 and) trying to ignore..");
*(int*)(uint32_t(EBP)+8)=1;
}
return;
}

最后,这里有一个问题:我如何制作这个钩子,不是用Ollydbg,而是用C++？(我看到一个源代码回来,一个MMORPG作弊程序,挂钩客户端,执行此操作,但代码丢失给我)

Answer 1

首先,您需要在目标进程中注入一个dll.为此,您可以使用以下代码:

Injector.h

#ifndef INJECTOR_H_INCLUDED
#define INJECTOR_H_INCLUDED

#include <Windows.h>
#include <string>

class Injector
{
public:
    /**
     * Loads a DLL into the remote process
     * @Return true on sucess, false on failure
    */
    bool InjectDll(DWORD processId, std::string dllPath);
private:
};

#endif // INJECTOR_H_INCLUDED

Injector.cpp

#include "Injector.h"

bool Injector::InjectDll(DWORD processId, std::string dllPath)
{
    HANDLE hThread, hProcess;
    void*  pLibRemote = 0;  // the address (in the remote process) where szLibPath will be copied to;

    HMODULE hKernel32 = GetModuleHandle("Kernel32");
    HINSTANCE hInst = GetModuleHandle(NULL);

    char DllFullPathName[_MAX_PATH];
    GetFullPathName(dllPath.c_str(), _MAX_PATH, DllFullPathName, NULL);

    // Get process handle
    hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, processId);

    // copy file path in szLibPath
    char szLibPath[_MAX_PATH];
    strcpy_s(szLibPath, DllFullPathName);

    // 1. Allocate memory in the remote process for szLibPath
    pLibRemote = VirtualAllocEx( hProcess, NULL, sizeof(szLibPath), MEM_COMMIT, PAGE_READWRITE );

    if (pLibRemote == NULL)
    {
        // probably because you don't have administrator's right
        return false;
    }

    // 2. Write szLibPath to the allocated memory
    WriteProcessMemory(hProcess, pLibRemote, (void*)szLibPath, sizeof(szLibPath), NULL);

    // 3. Force remote process to load dll
    hThread = CreateRemoteThread(hProcess, NULL, 0, (LPTHREAD_START_ROUTINE) GetProcAddress(hKernel32,"LoadLibraryA"), pLibRemote, 0, NULL);

    if (hThread == NULL)
    {
        return false;
    }

    return true;
}

main.cpp中

#include "Injector.h"
int main()
{
    Injector injector;
    DWORD processId = 1653; // change the process id here. 

    if (injector.InjectDll(processId, "injected.dll"))
    {
        printf("Good job, you injected the dll\n");
    }
    else
    {
        printf("Something wrong happened\n");
    }

    while (true);
}

然后你必须做你的DLL.这是它变得有点复杂的地方.首先一些包括:

injected.dll

#include <Windows.h>
#include <stdio.h>

然后我们需要创建一个绕过正确位置的函数:

void DetourAddress(void* funcPtr, void* hook, BYTE* mem)
{
    BYTE cmd[5] = { 0xE9, 0x00, 0x00, 0x00, 0x00 }; // jump place holder
    void* RVAaddr = (void*)((DWORD)funcPtr + (DWORD)GetModuleHandle(NULL)); // base + relative address

    // make memory readable/writable
    DWORD dwProtect;
    VirtualProtect(RVAaddr, 5, PAGE_EXECUTE_READWRITE, &dwProtect);

    // read memory
    ReadProcessMemory(GetCurrentProcess(), (LPVOID)RVAaddr, &mem[2], 5, NULL);

    // write jmp in cmd
    DWORD offset = ((DWORD)hook - (DWORD)RVAaddr - 5);  // (dest address) - (source address) - (jmp size)
    memcpy(&cmd[1], &offset, 4); // write address into jmp
    WriteProcessMemory(GetCurrentProcess(), (LPVOID)RVAaddr, cmd, 5, 0); // write jmp

    // write mem
    VirtualProtect(mem, 13, PAGE_EXECUTE_READWRITE, &dwProtect);

    void* returnAdress = (void*)((DWORD)RVAaddr + 5);
    memcpy(&mem[8], &returnAdress, 4); // write return address into mem

    // reprotect
    VirtualProtect(RVAaddr, 5, dwProtect, NULL);
}

如果您需要在某个时候删除您的DLL,您将需要恢复代码:

void PatchAddress(void* funcPtr, BYTE* mem)
{
    void* RVAaddr = (void*)((DWORD)funcPtr + (DWORD)GetModuleHandle(NULL)); // base + relative address

    // make memory readable/writable
    DWORD dwProtect;
    VirtualProtect(funcPtr, 5, PAGE_EXECUTE_READWRITE, &dwProtect);

    WriteProcessMemory(GetCurrentProcess(), (LPVOID)RVAaddr, &mem[2], 5, NULL); // write jmp

    VirtualProtect(RVAaddr, 5, dwProtect, NULL);
}

接下来,我们需要从绕行的字节中创建一个函数,以便程序执行它们,这样它就不会受到绕行的影响.在全球空间中添加:

// memory (0x5E = pop esi, 0x68 = push DWORD, 0xC3 = RETN)
BYTE detourMem[13] = { 0x5E, 0x5E, 0x0, 0x0, 0x0, 0x0, 0x0, 0x68, 0x00, 0x00, 0x00, 0x00, 0xC3 };

// Convert bytes array to function
typedef void ( * pFunc)();
pFunc funcMem = (pFunc) &detourMem;

// I also added a variable as an example of what you can do with it.
DWORD var = 0;

之后,你需要你的绕行功能:

_declspec(naked) void DetourFunction()
{
    // we need to push all flag and registers on the stack so we don't modify them by accident
    __asm
    {
        PUSHFD
        PUSHAD

        // You can do "whatever" you want here in assembly code
        // ex, put eax value into var:
        mov var, eax
    }

    printf("this code is executed everytime the detoured function is called\n");
    // Do whatever you want in c++ here
    if (var < 7)
    {
        // eax was smaller than 7
    }

    // We pop every flags and registers we first pushed so that the program continue as it was supposed to
    __asm
    {
        // we set everything back to normal
        POPAD
        POPFD
        push esi

        // we call our funcMem
        mov edx, funcMem;
        call edx
    }
}

最后,这是你的DLLMain的样子:

BOOL APIENTRY DllMain( HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved  )
{
    DWORD detouredAddress = 0x689B; // add the RELATIVE ADDRESS of the location you want to detour
    FILE *stream;
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        // Only add this if you want a console to appears when you inject your dll (don't forget FreeConsole when you remove the dll)
        AllocConsole();
        freopen_s(&stream, "CONOUT$", "w", stdout);

        // If you need to know the base address of the process your injected:   
        printf("base address: 0x%X\n", (DWORD)GetModuleHandle(NULL));

        // Our detour function
        DetourAddress((void*)detouredAddress, (void*)&DetourFunction, detourMem);
        break;
    case DLL_PROCESS_DETACH:
        // We restore the process to have what it was before it was injected
        PatchAddress((void*)detouredAddress, detourMem);

        FreeConsole();
        break;
    }

    return true;
}

我明白这一切都很多,所以如果你有任何问题请不要犹豫!