Application crashes when using hooked functions

Question

I've been trying to hook a few winapi functions, e.g. DrawText, TextOut, ExtTextOut using detours. In case of injecting my dll into windows calculator the hooked functions are working fine until i press a button on the calculator, which then causes a crash. Injecting my dll into other processes causes similar behaviour. All hooks are working fine until i trigger certain actions like opening the new file dialog in notepad.

I've tested my dll on 32 and 64 bit windows 7 systems, both shows the same behaviour.

Any ideas on what could be causing the problem?

My dll:

main.cpp

#include <Windows.h>
#include <detours.h>
#include "hookedFunctions.h"


BOOL APIENTRY DllMain( HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved )
{   
    switch (ul_reason_for_call){    
        case DLL_PROCESS_ATTACH: 
            DetourTransactionBegin(); 
            DetourUpdateThread(GetCurrentThread());
            DetourAttach(&(PVOID&)pDrawTextW, myDrawTextW);
            DetourAttach(&(PVOID&)pDrawTextA, myDrawTextA);
            DetourAttach(&(PVOID&)pExtTextOutW, myExtTextOutW);
            DetourAttach(&(PVOID&)pExtTextOutA, myExtTextOutA);
            DetourAttach(&(PVOID&)pTextOutW, myTextOutW);
            DetourAttach(&(PVOID&)pTextOutA, myTextOutA);
            DetourAttach(&(PVOID&)myPolyTextOutW, myPolyTextOutW);
            DetourAttach(&(PVOID&)myPolyTextOutA, myPolyTextOutA);
            if(DetourTransactionCommit() == NO_ERROR)
                OutputDebugStringA("Detoured successfully");

            break;
        case DLL_PROCESS_DETACH: 

            DetourTransactionBegin(); 
            DetourUpdateThread(GetCurrentThread());

            DetourDetach(&(PVOID&)pDrawTextW, myDrawTextW);
            DetourDetach(&(PVOID&)pDrawTextA, myDrawTextA);
            DetourDetach(&(PVOID&)pExtTextOutW, myExtTextOutW);
            DetourDetach(&(PVOID&)pExtTextOutA, myExtTextOutA);
            DetourDetach(&(PVOID&)pTextOutW, myTextOutW);
            DetourDetach(&(PVOID&)pTextOutA, myTextOutA);
            DetourDetach(&(PVOID&)myPolyTextOutW, myPolyTextOutW);
            DetourDetach(&(PVOID&)myPolyTextOutA, myPolyTextOutA);
            if(DetourTransactionCommit() == NO_ERROR)
                OutputDebugStringA("Detoured successfully");

            break;
    }
    return TRUE;
}

hookedFunctions.h

#pragma once

#include <Windows.h>

// Declare function pointers to original Windows API functions
extern int (WINAPI *pDrawTextW)(HDC, LPCTSTR, int, LPRECT, UINT);
extern int (WINAPI *pDrawTextA)(HDC, LPCSTR, int, LPRECT, UINT);
extern BOOL (WINAPI *pTextOutW)(HDC, int, int, LPCTSTR, int);
extern BOOL (WINAPI *pTextOutA)(HDC, int, int, LPCSTR, int);
extern BOOL (WINAPI *pExtTextOutW)(HDC, int, int, UINT, const RECT*, LPCTSTR, UINT, const INT*);
extern BOOL (WINAPI *pExtTextOutA)(HDC, int, int, UINT, const RECT*, LPCSTR, UINT, const INT*);
extern BOOL (WINAPI *pPolyTextOutW)(HDC, const POLYTEXTW* , int);
extern BOOL (WINAPI *pPolyTextOutA)(HDC, const POLYTEXTA* , int);


// Declare our custom functions which are used to override the original Windows API functions
int myDrawTextW(HDC, LPCTSTR, int, LPRECT, UINT);
int myDrawTextA(HDC, LPCSTR, int, LPRECT, UINT);
BOOL myTextOutW(HDC, int, int, LPCTSTR, int);
BOOL myTextOutA(HDC, int, int, LPCSTR, int);
BOOL myExtTextOutW(HDC, int, int, UINT, const RECT*, LPCTSTR , UINT, const INT*);
BOOL myExtTextOutA(HDC, int, int, UINT, const RECT*, LPCSTR , UINT, const INT*);
BOOL myPolyTextOutW(HDC, const POLYTEXTW*, int);
BOOL myPolyTextOutA(HDC, const POLYTEXTA*, int);

hookedFunctions.cpp

#include "hookedFunctions.h"


// Create and initialize function pointers to original Windows API functions
int (WINAPI *pDrawTextW)(HDC, LPCTSTR, int, LPRECT, UINT) = DrawTextW;
int (WINAPI *pDrawTextA)(HDC, LPCSTR, int, LPRECT, UINT) = DrawTextA;
BOOL (WINAPI *pTextOutW)( HDC, int, int, LPCTSTR, int) = TextOutW;
BOOL (WINAPI *pTextOutA)(HDC, int, int, LPCSTR, int) = TextOutA;
BOOL (WINAPI *pExtTextOutW)(HDC, int, int, UINT, const RECT*, LPCTSTR, UINT, const INT*) = ExtTextOutW;
BOOL (WINAPI *pExtTextOutA)(HDC, int, int, UINT, const RECT*, LPCSTR, UINT, const INT*) = ExtTextOutA;
BOOL (WINAPI *pPolyTextOutW)(HDC, const POLYTEXTW* , int) = PolyTextOutW;
BOOL (WINAPI *pPolyTextOutA)(HDC, const POLYTEXTA* , int) = PolyTextOutA;

// Custom versions of the Windows API functions, having the same parameters,
// return type, and calling convention as the versions provided by the OS.
int myDrawTextW(HDC hDC, LPCTSTR lpchText, int nCount, LPRECT lpRect, UINT uFormat)
{
    OutputDebugString(lpchText);
    return pDrawTextW(hDC, lpchText, nCount, lpRect, uFormat);
}

int myDrawTextA(HDC hDC, LPCSTR lpchText, int nCount, LPRECT lpRect, UINT uFormat)
{
    OutputDebugStringA(lpchText);
    return pDrawTextA(hDC, lpchText, nCount, lpRect, uFormat);
}


BOOL myTextOutW(HDC hdc, int nXStart, int nYStart, LPCTSTR lpString, int cchString)
{
    OutputDebugString(lpString);
    return pTextOutW(hdc, nXStart, nYStart, lpString, cchString);
}

BOOL myTextOutA(HDC hdc, int nXStart, int nYStart, LPCSTR lpString, int cchString)
{
    OutputDebugStringA(lpString);
    return pTextOutA(hdc, nXStart, nYStart, lpString, cchString);
}

BOOL myExtTextOutW(HDC hdc, int X, int Y, UINT fuOptions, const RECT *lprc, 
                  LPCTSTR lpString, UINT cbCount, const INT *lpDx)
{   
    OutputDebugString(lpString);
    return pExtTextOutW(hdc, X, Y, fuOptions, lprc, lpString, cbCount, lpDx);
}

BOOL myExtTextOutA(HDC hdc, int X, int Y, UINT fuOptions, const RECT *lprc, 
                  LPCSTR lpString, UINT cbCount, const INT *lpDx)
{   
    OutputDebugStringA(lpString);
    return pExtTextOutA(hdc, X, Y, fuOptions, lprc, lpString, cbCount, lpDx);
}

BOOL myPolyTextOutW(HDC hdc, const POLYTEXTW *pptxt, int cStrings)
{
    OutputDebugString(pptxt->lpstr);
    return pPolyTextOutW(hdc, pptxt, cStrings);
}

BOOL myPolyTextOutA(HDC hdc, const POLYTEXTA *pptxt, int cStrings)
{
    OutputDebugStringA(pptxt->lpstr);
    return pPolyTextOutA(hdc, pptxt, cStrings);
}

Answer 1

Problem solved - I forgot to add WINAPI to my functions. Headers must look like this: int WINAPI myDrawTextW(HDC, LPCTSTR, int, LPRECT, UINT);