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[SOLVED] My Recv Hook Crashes

 
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kinghamza
How do I cheat?
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Joined: 14 Aug 2009
Posts: 5
PostPosted: Sat Aug 22, 2009 6:20 am    Post subject: [SOLVED] My Recv Hook Crashes Reply with quote
Code:
typedef int (WINAPI *HOOKSEND)( SOCKET sendSocket, const char *szBuffer, int iLength, int iFlag );
typedef int (WINAPI *HOOKRECV)( SOCKET sendSocket, char FAR* szBuffer, int iLength, int iFlag );

int WINAPI HookSend( SOCKET sendSocket, const char *szBuffer, int iLength, int iFlag );
int WINAPI HookRecv( SOCKET sendSocket, char FAR* szBuffer, int iLength, int iFlag );
HOOKSEND HookSend_o;
HOOKRECV HookRecv_o;

BOOL WINAPI DllMain( HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved )
{
    static HANDLE hMainThread = NULL;

    switch( fdwReason )
    {
        case DLL_PROCESS_ATTACH:
        {
            hMainThread = CreateThread( 0, 0, (LPTHREAD_START_ROUTINE)ThreadMain, (void*)hinstDLL, 0, 0 );
            HookSend_o = (HOOKSEND)HookFunction( hinstDLL, "Ws2_32.dll", "send", (DWORD)HookSend, 5 );
            HookRecv_o = (HOOKRECV)HookFunction( hinstDLL, "Ws2_32.dll", "recv", (DWORD)HookRecv, 5 );
        }break;

        case DLL_PROCESS_DETACH:
        {
            if( hMainThread )
                CloseHandle( hMainThread );
        }break;
    }
    return TRUE;
}


DWORD HookFunction( HMODULE hModule, LPCWSTR DllName, LPCSTR ProcName, DWORD dwReplaced, DWORD dwReturn )
{
    DWORD dwOldProtect;
    DWORD dwAddressToHook = (DWORD)GetProcAddress(GetModuleHandle(DllName), ProcName);
    BYTE *pbTargetCode = (BYTE *)dwAddressToHook;
    BYTE *pbReplaced = (BYTE *)dwReplaced;
    VirtualProtect((LPVOID)dwAddressToHook, 5, PAGE_EXECUTE_READWRITE, &dwOldProtect);
    *pbTargetCode++ = 0xE9;
    *((signed int*)(pbTargetCode)) = pbReplaced - (pbTargetCode + 4);
    VirtualProtect( (LPVOID)dwAddressToHook, 5, PAGE_EXECUTE, &dwOldProtect );
    FlushInstructionCache( GetCurrentProcess(), NULL, NULL );

    return dwAddressToHook+dwReturn;
}


int WINAPI HookSend( SOCKET sendSocket, const char *szBuffer, int iLength, int iFlag )
{
    g_Socket = sendSocket;

    // works nice
    return HookSend_o( sendSocket, szBuffer, iLength, iFlag );
}


int WINAPI HookRecv( SOCKET sendSocket, char FAR* szBuffer, int iLength, int iFlag )
{

   
    // on return, the program crashes
    return HookRecv_o( sendSocket, szBuffer, iLength, iFlag );
}


//I made it work by modifying it like this
int WINAPI HookRecv( SOCKET sendSocket, char FAR* szBuffer, int iLength, int iFlag )
{
    int iResult = HookRecv_o( sendSocket, szBuffer, iLength, iFlag );
   
    //although it is working, the problem is that
   //the HookRecv_o never returns, this means
   //the code below never gets executed

    return iResult;
}


Last edited by kinghamza on Sat Aug 22, 2009 8:08 pm; edited 1 time in total
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Slugsnack
Grandmaster Cheater Supreme
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Joined: 24 Jan 2007
Posts: 1857
PostPosted: Sat Aug 22, 2009 7:02 am    Post subject: Reply with quote
looks like you have corrupted the stack because you never replaced the instructions you overwrote when placing your hook. those instructions were more than likely setting up the stack frame. but because you didn't replace them in your hook function, the return address changes to something random
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kinghamza
How do I cheat?
Reputation: 0

Joined: 14 Aug 2009
Posts: 5
PostPosted: Sat Aug 22, 2009 11:15 am    Post subject: Reply with quote
this solved it all. placed right before the end of the hook.
Code:

    __asm( "mov edi, edi\n" );
    __asm( "push ebp\n" );
    __asm( "mov ebp, esp\n" );

aww, i thought i didn't have to use inlines Crying or Very sad
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Slugsnack
Grandmaster Cheater Supreme
Reputation: 71

Joined: 24 Jan 2007
Posts: 1857
PostPosted: Sat Aug 22, 2009 3:28 pm    Post subject: Reply with quote
first line can be omitted, second and third can be put into the same line, eg :

Code:
__asm
{
  push ebp
  mov ebp, esp
}


or even

Code:
__asm push ebp __asm mov ebp, esp
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kinghamza
How do I cheat?
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Joined: 14 Aug 2009
Posts: 5
PostPosted: Sat Aug 22, 2009 8:08 pm    Post subject: Reply with quote
thanks Very Happy
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