// HookWProc.cpp.
#include "stdafx.h"
#include <stdio.h>

//---------------------------------------------------------------------
typedef LONG	(WINAPI *SETWINDOWLONG)	 (HWND,int,LONG); 
typedef BOOL	(WINAPI *SETWINDOWTEXT)	 (HWND,LPCSTR); 
typedef LRESULT	(WINAPI *CALLWINDOWPROC) (WNDPROC,HWND,UINT,WPARAM,LPARAM);

typedef struct {
	SETWINDOWLONG	fnSetWindowLong;
	CALLWINDOWPROC	fnCallWindowProc;	
	SETWINDOWTEXT	fnSetWindowText;
	HWND	        hwnd;
	WNDPROC	        fnNewProc;
	char            pszStr[20];
	WNDPROC         fnOldProc;	
} INJDATA, *PINJDATA;

//---------------------------------------------------------------------
DWORD WINAPI InjectFunc (INJDATA *pData) 
{
	pData->fnOldProc = (WNDPROC)pData->fnSetWindowLong 
		( pData->hwnd, GWL_WNDPROC,(long)pData->fnNewProc );

	return (pData->fnOldProc != NULL);
}

//---------------------------------------------------------------------
// 新的Windows過程函數(shù).
static LRESULT CALLBACK NewProc(HWND hwnd, 
								UINT uMsg, 
								WPARAM wParam, 
								LPARAM lParam )  
{	
	// 計(jì)算INJDATA的位置，注意在遠(yuǎn)進(jìn)程中INJDATA緊放在NewProc前.
	INJDATA* pData;

	_asm {				
		call	dummy
    dummy:
		pop		ecx			// 此時(shí)ECX 指向當(dāng)前 EIP (指示指針).
		sub		ecx,   14	// 此時(shí)ECX 指向 NewProc的地址.
		mov		pData, ecx
	}

	pData--;

	switch (uMsg) 
	{
		case WM_LBUTTONDOWN:
			break;
		case WM_PAINT:
			pData->fnSetWindowText(hwnd,pData->pszStr);
			break;
	}

	return pData->fnCallWindowProc
		 (pData->fnOldProc, hwnd,uMsg,wParam,lParam );		
}

//---------------------------------------------------------------------
int InjectCode (HWND hWnd, char *pszText)
{
	HANDLE	hProcess; 
	HANDLE	hThread;	
	DWORD   dwPID;
	BYTE	*pCodeRemote;
	BYTE    *pDataRemote;
	BYTE    *pNewProcRemote;
	DWORD	dwThreadId;
	DWORD   dwNumBytes;
	int	    nSuccess	= 0; 
	int     nNewProc    = 250;
    int     nInjectFunc = 1024;

	__try {
		GetWindowThreadProcessId( hWnd, &dwPID );
		hProcess = OpenProcess(	PROCESS_ALL_ACCESS, FALSE, dwPID);
		if (hProcess == NULL)
			__leave;		
		int size = sizeof(INJDATA) + nNewProc;
		
		pDataRemote = (BYTE*) VirtualAllocEx( hProcess, 0, 
			size, MEM_COMMIT, PAGE_EXECUTE_READWRITE );		

		if ( pDataRemote == NULL ) 
			__leave;		


		pNewProcRemote = pDataRemote + sizeof(INJDATA);
		WriteProcessMemory( hProcess, pNewProcRemote, 
			                 NewProc, nNewProc, &dwNumBytes);
		
		// 初始化INJDATA結(jié)構(gòu).
		HMODULE hUser32 = GetModuleHandle("user32");
		INJDATA DataLocal = {
			    (SETWINDOWLONG) GetProcAddress(hUser32, "SetWindowLongA"),
				(CALLWINDOWPROC)GetProcAddress(hUser32, "CallWindowProcA"),
				(SETWINDOWTEXT) GetProcAddress(hUser32, "SetWindowTextA"),
				hWnd,
				(WNDPROC) (pNewProcRemote)
		};
		
		strcpy(DataLocal.pszStr,pszText);

		if (DataLocal.fnSetWindowLong  == NULL || 			
			DataLocal.fnCallWindowProc == NULL ||
			DataLocal.fnSetWindowText  == NULL)
			__leave;		
		
		// 把初始化的INJDATA拷貝到遠(yuǎn)進(jìn)程中.
		WriteProcessMemory( hProcess,pDataRemote, 
			 &DataLocal, sizeof(INJDATA), &dwNumBytes);
		
		pCodeRemote = (BYTE*) VirtualAllocEx( 
			hProcess, 0, nInjectFunc, MEM_COMMIT, PAGE_EXECUTE_READWRITE );

		if ( pCodeRemote == 0 )
			__leave;

		WriteProcessMemory( hProcess, pCodeRemote,
			          InjectFunc, nInjectFunc, &dwNumBytes);

		// Start execution of remote InjectFunc
		hThread = CreateRemoteThread(hProcess, NULL, 0, 
				(LPTHREAD_START_ROUTINE) pCodeRemote,
				pDataRemote, 0 , &dwThreadId);
		if ( hThread == 0 )
			__leave;

		WaitForSingleObject(hThread, INFINITE);
		GetExitCodeThread(hThread, (PDWORD) &nSuccess);
	}
	__finally {
		if( !nSuccess )		
			VirtualFreeEx( hProcess, pDataRemote, 0, MEM_RELEASE );

		if ( pCodeRemote != NULL )
			VirtualFreeEx( hProcess, pCodeRemote, 0, MEM_RELEASE );

		if ( hThread != NULL )			
			CloseHandle(hThread);

		if ( hProcess != NULL )			
			CloseHandle( hProcess );
	}

	return nSuccess;
}

void NewProcCode()
{
// 定義最大代碼長度.
#define Max_Sc_Len     45   
	
	char buffer[Max_Sc_Len];
	// 復(fù)制代碼到buffer.
	memcpy(buffer,(char *)NewProc,Max_Sc_Len);
	
	// 顯示代碼.
	for(int i=0;i<Max_Sc_Len;i++){
		printf("  %02x", buffer[i]&0xff);
	}

	getchar();
}

void main()
{
//  調(diào)用顯示NewProc()函數(shù)代碼的函數(shù).
//	NewProcCode();

	HWND hWnd;
	hWnd = FindWindow (NULL,TEXT("HookMsgbx"));
	if(!hWnd) return;
	hWnd = FindWindowEx (hWnd, NULL,TEXT("BUTTON"),"確定");	
	if(!hWnd) return;
    InjectCode(hWnd,"Hello!");
}