CODEWITHSUNDEEP
c++dllhookdll-injectionsetwindowshookex
Binder
Binder

Reputation: 83

SetWindowsHookEx with WH_KEYBOARD stuck in a loop/queue

I am trying to hook a Notepad with dll-injection. After the exe is run and hooks the Notepad (form what I can tell successfully) and some keys are pressed, what seems to happan is that the key presses get stuck in a loop or a queue (Notepad not responding). After the exe unhooks the Notepad responds and all pressed keys appear in the text field.

exe

#include <iostream>
#include <fstream>
#include <windows.h>
#include <stdio.h>

HHOOK       hHook     = NULL;
HWND        handle    = NULL;
HMODULE     dll       = NULL;
HOOKPROC    address   = NULL;
DWORD       thread_id = 0;

using namespace std;

int main(){

    handle=FindWindow(NULL,L"Untitled - Notepad");
    if(handle==NULL){
        cout<<"Window not found"<<endl;
        getchar();
        return 0;
    }

    thread_id=GetWindowThreadProcessId(handle,NULL);
    if(thread_id==0){
        cout<<"ID not found"<<endl;
        getchar();
        return 0;
    }

    dll = LoadLibrary(TEXT("X:\\qt\\hook\\debug\\hook.dll"));
    if(dll==NULL){
        cout<<"hook.dll not found"<<endl;
        getchar();
        return 0;
    }

    address=(HOOKPROC)GetProcAddress(dll,"CallWndProc@12");
    if(address==NULL){
        cout<<"Address not found"<<endl;
        getchar();
        return 0;
    }

    hHook=SetWindowsHookEx(WH_KEYBOARD,address,dll,thread_id);
    if(hHook==NULL){
        cout<<"hook was not set"<<endl;
        return 0;
    }

    cout<<"Program successfully hooked"<<endl;
    cout<<"Press enter to unhook the function and stop the program"<<endl;
    getchar();
    UnhookWindowsHookEx(hHook);

    return 0;
}

dll

#include "hook.h"
#include <windows.h>
#include <iostream>
#include <fstream>

using namespace std;

extern "C"{
    __declspec(dllexport) LRESULT CALLBACK CallWndProc(int nCode,WPARAM wParam,LPARAM lParam){

        if(nCode<0){
           return CallNextHookEx(NULL,nCode,wParam,lParam);
        }

        ofstream file;
        file.open("X:\\qt\\klog\\debug\\function.txt");
        file<<"Function keyboard_hook called\n";
        file.close();
        return CallNextHookEx(NULL,nCode,wParam,lParam);
    }
}

BOOL APIENTRY DllMain(HMODULE hDLL, DWORD Reason, LPVOID Reserved){

    switch(Reason) {
    case DLL_PROCESS_ATTACH: break;
    case DLL_PROCESS_DETACH: break;
    case DLL_THREAD_ATTACH:  break;
    case DLL_THREAD_DETACH:  break;
    }

    return TRUE;
}

Upvotes: 2

Views: 1283

Answers (1)

Binder
Binder

Reputation: 83

Adding an message loop between SetWindowsHookEx and UnhookWindowsHookEx fixed it

while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
    TranslateMessage(&Msg);
    DispatchMessage(&Msg);
}

Upvotes: 1

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