API Hook
2009-06-25 16:06
|
http://www.programfan.com/article/showarticle.asp?id=2786
其中Dll文件为： HHOOK g_hHook; HINSTANCE g_hinstDll; FARPROC pfMessageBoxA; int WINAPI MyMessageBoxA(HWND hWnd, LPCTSTR lpText,LPCTSTR lpCaption,UINT uType); BYTE OldMessageBoxACode[5],NewMessageBoxACode[5]; HMODULE hModule ; DWORD dwIdOld,dwIdNew; BOOL bHook=false; void HookOn(); void HookOff(); BOOL init(); LRESULT WINAPI MousHook(int nCode,WPARAM wParam,LPARAM lParam); BOOL APIENTRY DllMain( HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved ) { switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: if(!init()) { MessageBoxA(NULL,"Init","ERROR",MB_OK); return(false); } case DLL_THREAD_ATTACH: case DLL_THREAD_DETACH: case DLL_PROCESS_DETACH: if(bHook) UnintallHook(); break; } return TRUE; } LRESULT WINAPI Hook(int nCode,WPARAM wParam,LPARAM lParam)//空的钩子函数 { return(CallNextHookEx(g_hHook,nCode,wParam,lParam)); } HOOKAPI2_API BOOL InstallHook()//输出安装空的钩子函数 { g_hinstDll=LoadLibrary("HookApi2.dll"); g_hHook=SetWindowsHookEx(WH_GETMESSAGE,(HOOKPROC)Hook,g_hinstDll,0); if (!g_hHook) { MessageBoxA(NULL,"SET ERROR","ERROR",MB_OK); return(false); } return(true); } HOOKAPI2_API BOOL UninstallHook()//输出御在钩子函数 { return(UnhookWindowsHookEx(g_hHook)); } BOOL init()//初始化得到MessageBoxA的地址，并生成Jmp XXX(MyMessageBoxA)的跳转指令 { hModule=LoadLibrary("user32.dll"); pfMessageBoxA=GetProcAddress(hModule,"MessageBoxA"); if(pfMessageBoxA==NULL) return false; _asm { lea edi,OldMessageBoxACode mov esi,pfMessageBoxA cld movsd movsb } NewMessageBoxACode[0]=0xe9;//jmp MyMessageBoxA的相对地址的指令 _asm { lea eax,MyMessageBoxA mov ebx,pfMessageBoxA sub eax,ebx sub eax,5 mov dword ptr [NewMessageBoxACode+1],eax } dwIdNew=GetCurrentProcessId(); //得到所属进程的ID dwIdOld=dwIdNew; HookOn();//开始拦截 return(true); } int WINAPI MyMessageBoxA(HWND hWnd, LPCTSTR lpText,LPCTSTR lpCaption, UINT uType )//首先关闭拦截，然后才能调用被拦截的Api 函数 { int nReturn=0; HookOff(); nReturn=MessageBoxA(hWnd,"Hook",lpCaption,uType); HookOn(); return(nReturn); } void HookOn() { HANDLE hProc; dwIdOld=dwIdNew; hProc=OpenProcess(PROCESS_ALL_ACCESS,0,dwIdOld);//得到所属进程的句柄 VirtualProtectEx(hProc,pfMessageBoxA,5,PAGE_READWRITE,&dwIdOld); //修改所属进程中MessageBoxA的前5个字节的属性为可写 WriteProcessMemory(hProc,pfMessageBoxA,NewMessageBoxACode,5,0); //将所属进程中MessageBoxA的前5个字节改为JMP 到MyMessageBoxA VirtualProtectEx(hProc,pfMessageBoxA,5,dwIdOld,&dwIdOld); //修改所属进程中MessageBoxA的前5个字节的属性为原来的属性 bHook=true; } void HookOff()//将所属进程中JMP MyMessageBoxA的代码改为Jmp MessageBoxA { HANDLE hProc; dwIdOld=dwIdNew; hProc=OpenProcess(PROCESS_ALL_ACCESS,0,dwIdOld); VirtualProtectEx(hProc,pfMessageBoxA,5,PAGE_READWRITE,&dwIdOld); WriteProcessMemory(hProc,pfMessageBoxA,OldMessageBoxACode,5,0); VirtualProtectEx(hProc,pfMessageBoxA,5,dwIdOld,&dwIdOld); bHook=false; } //测试文件： int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { if(!InstallHook()) { MessageBoxA(NULL,"Hook Error!","Hook",MB_OK); return 1; } MessageBoxA(NULL,"TEST","TEST",MB_OK);//可以看见Test变成了Hook,也可以在其他进程中看见 if(!UninstallHook()) { MessageBoxA(NULL,"Uninstall Error!","Hook",MB_OK); return 1; } return 0; } |