Is it possible to subclass a web browser using winapi c++? - winapi

Question

The main goal is to block maximalize web browser window using subclassing and dll.
I have 2 apps: injector and the dll.
In injector app I load that dll, find window by title, get functions from dll and execute that functions ( their names are hook and unhook ) from dll. So this is standard injector. Of course I check is something NULL and I don't get any errors.
In dll I have 5 functions:
dllMain (here I only set global hInstance variable, which is in shared memory ):
BOOL WINAPI DllMain(HINSTANCE hinstDLL,DWORD fdwReason,LPVOID lpvReserved)
{
switch(fdwReason)
{
case DLL_PROCESS_ATTACH:
{
if (hInstance == NULL)
{
hInstance = hinstDLL;
}
break;
}
...
}
return TRUE;
}
Hook ( HandleofTarget is the HWND, which I get from FindWindow ; I use this function in injector ):
extern "C" __declspec(dllexport) bool hook( HWND HandleofTarget)
{
hTarget=HandleofTarget;
hhook=SetWindowsHookEx(WH_CBT,cbtHookProc,hInstance, GetWindowThreadProcessId(hTarget,NULL));
if(hhook==NULL)
return 0;
else
return 1;
}
Unhook ( here I unhook hooks - I use this function in injector):
extern "C" __declspec(dllexport) void unhook(void)
{
if(hhook != NULL)
UnhookWindowsHookEx( hhook );
}
cbtHookProc ( hook callback, where I change window procedure ):
LRESULT CALLBACK cbtHookProc( int code, WPARAM wParam, LPARAM lParam )
{
if( code < 0 ) return CallNextHookEx( 0, code, wParam, lParam );
if (code == HCBT_ACTIVATE)
{
if((HWND)(wParam)==hTarget)
{
if(done == FALSE)
{
g_OldWndProc =(WNDPROC)(SetWindowLongPtr ( (HWND)(wParam), GWLP_WNDPROC,reinterpret_cast<LONG_PTR>( NewWndProc )));
done = TRUE;
}
}
}
return CallNextHookEx( 0, code, wParam, lParam );
}
NewWndProc ( new Window procedure, where I would like to block maximalize ):
LRESULT CALLBACK NewWndProc( HWND hwnd, UINT mesg, WPARAM wParam, LPARAM lParam )
{
switch( mesg )
{
case WM_SYSCOMMAND:
{
if(wParam == SC_MAXIMIZE)
{
return 1;
}
}
break;
}
return CallWindowProc( g_OldWndProc, hwnd, mesg, wParam, lParam );
}
When I test this dll with other apps - it works. When I use this dll with web browser like Internet Edge and Google Chrome - it doesn't works. That web browser, which I try injected works slower, but I can still maximalize that window. When I debuq dll, in web browser after SetWindowsHookEx I see that hook is not NULL, but my code doesn't go to cbtHookProc. What is going on with web browser?
UPDATE:
One more time - thank you Strive Sun - MSFT for helping me.
I change the lines in cbtHookProc, but it still doesn't work. My cbtHookProc is don't called by webBrowser - that is problem.
When I looked at your gif I see something what I don't have and I think that is the problem. My injector app looks like this:
hDll = LoadLibrary( L"dllka10" );
hHookedWindow=FindWindow(TEXT("Chrome_WidgetWin_1"),TEXT("Nowa karta - Google Chrome"));
if( hDll && hHookedWindow)
{
qDebug()<<"hDll and hHookedWindow are not NULL!";
funHook =( MYPROC2 ) GetProcAddress( hDll, (LPCSTR) "hook" );
funUnhook = ( MYPROC ) GetProcAddress( hDll, (LPCSTR) "unhook" );
if( funHook )
{
qDebug()<<funHook(hHookedWindow);
}
}
I don't use CreateThread(). Is it important here?
UPDATED 2
LRESULT CALLBACK cbtHookProc( int code, WPARAM wParam, LPARAM lParam )
{
if( code < 0 ) return CallNextHookEx( 0, code, wParam, lParam );
std::fstream file;
file.open("C:\\Users\\tom\\Desktop\\logs.txt",std::ios::out|std::ios::app);
file<<"In cbtHook function!"<<std::endl;
file.close();
if (code == HCBT_MINMAX)
{
if (LOWORD(lParam) == SW_SHOWMAXIMIZED)
{
return 1;
}
}
return CallNextHookEx( 0, code, wParam, lParam );
}
When I run chrome application - my logs.txt is empty. When I run other app - I have logs.
UPDATED 3
In my dll I have:
#ifdef __GNUC__
HWND hTarget __attribute__((section (".shared"), shared)) =NULL;
HWND hApp __attribute__((section (".shared"), shared)) = NULL;
bool done __attribute__((section (".shared"), shared)) =FALSE;
HINSTANCE hInstance __attribute__((section (".shared"), shared)) =NULL;
HHOOK hhook __attribute__((section (".shared"), shared)) = NULL;
WNDPROC g_OldWndProc __attribute__((section (".shared"), shared)) = NULL;
#endif
#ifdef _MSC_VER
#pragma data_seg(".shared")
HWND hTarget=NULL;
HWND hApp = NULL;
bool done=FALSE;
HINSTANCE hInstance=NULL;
HHOOK hhook = NULL;
WNDPROC g_OldWndProc = NULL;
#pragma data_seg()
#pragma comment(linker, "/section:.shared,RWS")
#endif
in my injector I don't have any pragma - I have only ( QT ):
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
#include <iostream>
#include "string.h"
#include "windows.h"

Answer 1

I can't reproduce your problem, but you can try another easier method.
HCBT_MINMAX : Specifies, in the low-order word, a show-window value
(SW_) specifying the operation. For a list of show-window values, see
the ShowWindow. The high-order word is undefined.
if (code == HCBT_MINMAX)
{
if (LOWORD(lParam) == SW_SHOWMAXIMIZED)
{
return 1;
}
}
No need to use HCBT_ACTIVATE to obtain window handles and compare their handles.
Updated:
Code works fine.
My code sample:
DLL:
// dllmain.cpp : Defines the entry point for the DLL application.
#include "pch.h"
#include "stdio.h"
#include <windows.h>
HHOOK hCBT = NULL;
HWND hTarget;
HMODULE thisModule;
LRESULT CALLBACK _cbtProc(int code, WPARAM wParam, LPARAM lParam)
{
if (code < 0) return CallNextHookEx(0, code, wParam, lParam);
if (code == HCBT_MINMAX)
{
if (LOWORD(lParam) == SW_SHOWMAXIMIZED)
{
return 1;
}
}
return CallNextHookEx(0, code, wParam, lParam);
}
#ifdef __cplusplus //If used by C++ code.
extern "C" { //we need to export the C interface
#endif
__declspec(dllexport) BOOL WINAPI InstallHooks(HWND HandleofTarget)
{
hTarget = HandleofTarget;
DWORD tid = GetWindowThreadProcessId(hTarget, NULL);
hCBT = SetWindowsHookEx(WH_CBT, _cbtProc, thisModule, tid);
return (hCBT) ? TRUE : FALSE;
}
#ifdef __cplusplus
}
#endif
#ifdef __cplusplus //If used by C++ code.
extern "C" { //we need to export the C interface
#endif
__declspec(dllexport) void WINAPI RemoveHooks()
{
UnhookWindowsHookEx(hCBT);
MessageBox(NULL, L"unhook", L" ", MB_OK);
hCBT = NULL;
}
#ifdef __cplusplus
}
#endif
BOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
thisModule = hModule;
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
main.cpp
#include <Windows.h>
#include <stdio.h>
#include <psapi.h>
#include <shlwapi.h>
#include <tchar.h>
#pragma comment(lib,"Kernel32.lib")
#pragma comment(lib,"shlwapi.lib")
#pragma comment(linker, "/SECTION:.shared,RWS")
using namespace std;
HINSTANCE hinstDLL;
typedef void (*RemoveHooks)();
DWORD __stdcall CreateThreadFunc(LPVOID)
{
while (1)
{
if (GetAsyncKeyState(0x50) & 0x0001)
{
RemoveHooks removeHooks = (RemoveHooks)GetProcAddress(hinstDLL, "RemoveHooks");
removeHooks();
}
}
return 0;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
if (message == WM_DESTROY) {
PostQuitMessage(0);
}
return DefWindowProc(hwnd, message, wParam, lParam);
};
int main()
{
HWND hwnd = FindWindow(L"Chrome_WidgetWin_1", L"Google Translate - Google Chrome");
CreateThread(NULL, 0, CreateThreadFunc, 0, 0, 0);
hinstDLL = LoadLibrary(TEXT("D:\\Start from 11.2\\WM_CBT_DLL\\x64\\Debug\\WM_CBT_DLL.dll"));
BOOL(*InstallHooks)(HWND);
InstallHooks = (BOOL(*)(HWND)) GetProcAddress(hinstDLL, "InstallHooks");
BOOL l = InstallHooks(hwnd);
int err = GetLastError();
MSG msg = {};
while (GetMessage(&msg, NULL, 0, 0)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}