【文章标题】:Hook Com接口函数
  【文章作者】:yhswwr(SilenceRet)
  【作者ＱＱ】:3412259
  【编写语言】:C++
  【使用工具】:VS2008.VC++9
  【本文链接】:http://bbs.pediy.com/showthread.php?p=1266677
  【参考链接】:http://bbs.pediy.com/showthread.php?p=1266677
  【作者声明】:该贴仅供参考，失误之处请指教　转载请注名出处

DWORD* CHook::GetComProcAddrPointer( HMODULE hMod,LPCTSTR szClsGuid,LPCTSTR szDispatchGuid,LPCTSTR szFunctionName,LPSTR szErrMsg/*=NULL*/ )
{
	DWORD *pdwResult=NULL;

	USES_CONVERSION;
	CString strDispatchGuid(szDispatchGuid);

	//得到模块全路径
	CStringW strDllFilePathW;
	DWORD dwSize=::GetModuleFileNameW(hMod,strDllFilePathW.GetBuffer(1025),1024);
	strDllFilePathW.ReleaseBuffer(dwSize);

	//载入TypeLib
	ITypeLib *pLib;
	HRESULT ret=::LoadTypeLib(strDllFilePathW,&pLib);
	if (ret!=S_OK)
	{
		if(szErrMsg) strcpy(szErrMsg,"载入TypeLib失败");
		return pdwResult;
	}

	//得到接口函数偏移
	int nFunctionOffset=-1;

	int nTypeInfoCount=pLib->GetTypeInfoCount();
	for (int i=0;i<nTypeInfoCount;i++)
	{
		ITypeInfo *pTypeInfo;
		ret=pLib->GetTypeInfo(i,&pTypeInfo);

		TYPEATTR* pta;
		ret=pTypeInfo->GetTypeAttr(&pta);

		if (pta->typekind==TKIND_DISPATCH)
		{
			CString strGuid;
			strGuid.Format(_T("{%08X-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X}"),
				pta->guid.Data1,pta->guid.Data2,pta->guid.Data3  
				,pta->guid.Data4[0],pta->guid.Data4[1],pta->guid.Data4[2],pta->guid.Data4[3],
				pta->guid.Data4[4],pta->guid.Data4[5],pta->guid.Data4[6],pta->guid.Data4[7]);
			
			if (strDispatchGuid.CompareNoCase(strGuid)==0)	//比较DispatchGuid
			{
				int nFunCount=pta->cFuncs;
				for (int j=0;j<nFunCount;j++)
				{
					FUNCDESC* pfd;
					pTypeInfo->GetFuncDesc(j, &pfd);

					BSTR bstrName;
					pTypeInfo->GetDocumentation(pfd->memid, &bstrName,NULL, NULL, NULL);
					pTypeInfo->ReleaseFuncDesc(pfd);
					CString strFunName(W2A(bstrName));
					if (strFunName.CompareNoCase(szFunctionName)==0)	//比较函数名
					{
						nFunctionOffset=j;
						break;
					}
				}
			}
		}
		pTypeInfo->ReleaseTypeAttr(pta);
		if (nFunctionOffset!=-1) break;
	}
	if (nFunctionOffset==-1)
	{
		if(szErrMsg) strcpy(szErrMsg,"查找接口函数失败");
		return pdwResult;
	}

	typedef int (WINAPI *DllGetClassObjectPtr)(REFCLSID, REFIID, LPVOID*);

	//得到DllGetClassObject函数地址
	DllGetClassObjectPtr pDllGetClassObject = (DllGetClassObjectPtr)GetProcAddress(hMod, "DllGetClassObject");

	CoInitialize(NULL);

	CLSID rclsid;
	IID riid;
	::CLSIDFromString(A2W(szClsGuid), &rclsid);//类ID
	::IIDFromString(A2W(szDispatchGuid), &riid);//接口ID

	IClassFactory *pICF = NULL;//类工厂接口指针
	
	if(pDllGetClassObject(rclsid, IID_IClassFactory, (void**)(&pICF))==S_OK)//获取类工厂接口指针
	{
		DWORD *pClassObject=NULL;
		if(pICF->CreateInstance(NULL, riid, (void**)&pClassObject)==S_OK)//创建COM对象	
		{
			pdwResult=(DWORD *)*pClassObject+nFunctionOffset;
		}else{
			if(szErrMsg) strcpy(szErrMsg,"创建COM对象失败");
		}
		pICF->Release();
	}else{
		if(szErrMsg) strcpy(szErrMsg,"获取类工厂接口指针失败");
	}
	
	CoUninitialize();
	return pdwResult;
}

DWORD CHook::HookComFunction( HMODULE hMod,LPCTSTR szClsGuid,LPCTSTR szDispatchGuid,LPCTSTR szFunctionName,DWORD dwNewFunAddr )
{
	CHAR szErrMsg[64]={0};
	DWORD *pAddress=GetComProcAddrPointer(hMod,szClsGuid,szDispatchGuid,szFunctionName,szErrMsg);
	if (!pAddress) MsgErrorAndExitProcess(szErrMsg);
	
	DWORD dwResult=*pAddress;
	
	DWORD dwTmp=dwNewFunAddr;
	CMemory::WriteMemory((DWORD)pAddress,(BYTE *)&dwTmp,4);
	return dwResult;
}

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