[英]Win32, How can i hook functions in compiled programs with C++?
以这个功能为例(在Ollydbg调试器中查看)
第一条PUSH EBP指令是void * f(int32_t n)(它返回的结果,只是猜测void *)的开始,我知道输入参数n在堆栈中,并且EBP + 8是指向该变量,我想这就像int * n =(int *)(uint32_t(EBP)+ 0x08); / *假设EBP为void *,并且sizeof(EBP)== sizeof(uint32_t)== sizeof(void *),并且+8数学在c ++ uint32_t和x86汇编中是相同的。.* /
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,我可以这样做:修补第一个MOV EBP, ESP指令将JMP缩短到其后面的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指向文件末尾的未使用的0x000000000000
,然后在0068BCCD上,我可以编写汇编代码以检查EBP + 8指向的int,并在必要时进行修改:
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
哪一个(如果我没搞砸的话)基本上等于
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,这里是一个问题:我该如何使用C ++而不是Ollydbg来创建此钩子? (我看到一个源代码,一个MMORPG作弊程序,钩住了客户端,这样做,但是代码对我来说是丢失的)
首先,您将要在目标进程中注入一个dll。 为此,您可以使用以下代码:
喷油器
#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
喷油器
#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
#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,您必须制作您的dll。 这就是它变得更加复杂的地方。 首先包括:
注入文件
#include <Windows.h>
#include <stdio.h>
然后,我们需要制作一个可以绕开正确位置的函数:
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dll,则需要恢复代码:
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,以便它不受绕行的影响。 将其添加到全局空间:
// 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,您需要绕行功能:
_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,这是您的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;
}
我了解这是一次很多,所以如果您有任何疑问,请不要犹豫!
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