#include "stdafx.h" typedef BOOL (__stdcall *ProcDllMain)(HINSTANCE, DWORD, LPVOID ); class CMemLoadDll { public: CMemLoadDll(); ~CMemLoadDll(); BOOL MemLoadLibrary( void* lpFileData , int DataLength); // Dll file data buffer FARPROC MemGetProcAddress(LPCSTR lpProcName); private: BOOL isLoadOk; BOOL CheckDataValide(void* lpFileData, int DataLength); int CalcTotalImageSize(); void CopyDllDatas(void* pDest, void* pSrc); BOOL FillRavAddress(void* pBase); void DoRelocation(void* pNewBase); int GetAlignedSize(int Origin, int Alignment); private: ProcDllMain pDllMain; private: DWORD pImageBase; PIMAGE_DOS_HEADER pDosHeader; PIMAGE_NT_HEADERS pNTHeader; PIMAGE_SECTION_HEADER pSectionHeader; }; CMemLoadDll::CMemLoadDll() { isLoadOk = FALSE; pImageBase = NULL; pDllMain = NULL; } CMemLoadDll::~CMemLoadDll() { if(isLoadOk) { ASSERT(pImageBase != NULL); ASSERT(pDllMain != NULL); //脱钩，准备卸载dll pDllMain((HINSTANCE)pImageBase,DLL_PROCESS_DETACH,0); VirtualFree((LPVOID)pImageBase, 0, MEM_RELEASE); } } //MemLoadLibrary函数从内存缓冲区数据中加载一个dll到当前进程的地址空间，缺省位置0x10000000 //返回值： 成功返回TRUE , 失败返回FALSE //lpFileData: 存放dll文件数据的缓冲区 //DataLength: 缓冲区中数据的总长度 BOOL CMemLoadDll::MemLoadLibrary(void* lpFileData, int DataLength) { if(pImageBase != NULL) { return FALSE; //已经加载一个dll，还没有释放，不能加载新的dll } //检查数据有效性，并初始化 if(!CheckDataValide(lpFileData, DataLength))return FALSE; //计算所需的加载空间 int ImageSize = CalcTotalImageSize(); if(ImageSize == 0) return FALSE; // 分配虚拟内存 void *pMemoryAddress = VirtualAlloc((LPVOID)0x10000000, ImageSize, MEM_COMMIT|MEM_RESERVE, PAGE_EXECUTE_READWRITE); if(pMemoryAddress == NULL) return FALSE; else { CopyDllDatas(pMemoryAddress, lpFileData); //复制dll数据，并对齐每个段 //重定位信息 if(pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress >0 && pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size>0) { DoRelocation(pMemoryAddress); } //填充引入地址表 if(!FillRavAddress(pMemoryAddress)) { //修正引入地址表失败 VirtualFree(pMemoryAddress,0,MEM_RELEASE); return FALSE; } //修改页属性。应该根据每个页的属性单独设置其对应内存页的属性。这里简化一下。 //统一设置成一个属性PAGE_EXECUTE_READWRITE unsigned long old; VirtualProtect(pMemoryAddress, ImageSize, PAGE_EXECUTE_READWRITE,&old); } //修正基地址 pNTHeader->OptionalHeader.ImageBase = (DWORD)pMemoryAddress; //接下来要调用一下dll的入口函数，做初始化工作。 pDllMain = (ProcDllMain)(pNTHeader->OptionalHeader.AddressOfEntryPoint +(DWORD) pMemoryAddress); BOOL InitResult = pDllMain((HINSTANCE)pMemoryAddress,DLL_PROCESS_ATTACH,0); if(!InitResult) { //初始化失败 pDllMain((HINSTANCE)pMemoryAddress,DLL_PROCESS_DETACH,0); VirtualFree(pMemoryAddress,0,MEM_RELEASE); pDllMain = NULL; return FALSE; } isLoadOk = TRUE; pImageBase = (DWORD)pMemoryAddress; return TRUE; } //MemGetProcAddress函数从dll中获取指定函数的地址 //返回值： 成功返回函数地址 , 失败返回NULL //lpProcName: 要查找函数的名字或者序号 FARPROC CMemLoadDll::MemGetProcAddress(LPCSTR lpProcName) { if(pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress == 0 || pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size == 0) return NULL; if(!isLoadOk) return NULL; DWORD OffsetStart = pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress; DWORD Size = pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size; PIMAGE_EXPORT_DIRECTORY pExport = (PIMAGE_EXPORT_DIRECTORY)((DWORD)pImageBase + pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress); int iBase = pExport->Base; int iNumberOfFunctions = pExport->NumberOfFunctions; int iNumberOfNames = pExport->NumberOfNames; //<= iNumberOfFunctions LPDWORD pAddressOfFunctions = (LPDWORD)(pExport->AddressOfFunctions + pImageBase); LPWORD pAddressOfOrdinals = (LPWORD)(pExport->AddressOfNameOrdinals + pImageBase); LPDWORD pAddressOfNames = (LPDWORD)(pExport->AddressOfNames + pImageBase); int iOrdinal = -1; if(((DWORD)lpProcName & 0xFFFF0000) == 0) { //IT IS A ORDINAL! iOrdinal = (DWORD)lpProcName & 0x0000FFFF - iBase; } else { //use name int iFound = -1; for(int i=0; i<iNumberOfNames; i++) { char* pName= (char* )(pAddressOfNames[i] + pImageBase); if(strcmp(pName, lpProcName) == 0) { iFound = i; break; } } if(iFound >= 0) { iOrdinal = (int)(pAddressOfOrdinals[iFound]); } } if(iOrdinal < 0 || iOrdinal >= iNumberOfFunctions ) return NULL; else { DWORD pFunctionOffset = pAddressOfFunctions[iOrdinal]; if(pFunctionOffset > OffsetStart && pFunctionOffset < (OffsetStart+Size))//maybe Export Forwarding return NULL; else return (FARPROC)(pFunctionOffset + pImageBase); } } // 重定向PE用到的地址 void CMemLoadDll::DoRelocation( void *NewBase) { /* 重定位表的结构： // DWORD sectionAddress, DWORD size (包括本节需要重定位的数据) // 例如 1000节需要修正5个重定位数据的话，重定位表的数据是 // 00 10 00 00 14 00 00 00 xxxx xxxx xxxx xxxx xxxx 0000 // ----------- ----------- ---- // 给出节的偏移 总尺寸=8+6*2 需要修正的地址 用于对齐4字节 // 重定位表是若干个相连，如果address 和 size都是0 表示结束 // 需要修正的地址是12位的，高4位是形态字，intel cpu下是3 */ //假设NewBase是0x600000,而文件中设置的缺省ImageBase是0x400000,则修正偏移量就是0x200000 DWORD Delta = (DWORD)NewBase - pNTHeader->OptionalHeader.ImageBase; //注意重定位表的位置可能和硬盘文件中的偏移地址不同，应该使用加载后的地址 PIMAGE_BASE_RELOCATION pLoc = (PIMAGE_BASE_RELOCATION)((unsigned long)NewBase + pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress); while((pLoc->VirtualAddress + pLoc->SizeOfBlock) != 0) { //开始扫描重定位表 WORD *pLocData = (WORD *)((int)pLoc + sizeof(IMAGE_BASE_RELOCATION)); //计算本节需要修正的重定位项（地址）的数目 int NumberOfReloc = (pLoc->SizeOfBlock - sizeof(IMAGE_BASE_RELOCATION))/sizeof(WORD); for( int i=0 ; i < NumberOfReloc; i++) { if( (DWORD)(pLocData[i] & 0xF000) == 0x00003000) { //这是一个需要修正的地址 // 举例： // pLoc->VirtualAddress = 0x1000; // pLocData[i] = 0x313E; 表示本节偏移地址0x13E处需要修正 // 因此 pAddress = 基地址 + 0x113E // 里面的内容是 A1 ( 0c d4 02 10) 汇编代码是： mov eax , [1002d40c] // 需要修正1002d40c这个地址 DWORD * pAddress = (DWORD *)((unsigned long)NewBase + pLoc->VirtualAddress + (pLocData[i] & 0x0FFF)); *pAddress += Delta; } } //转移到下一个节进行处理 pLoc = (PIMAGE_BASE_RELOCATION)((DWORD)pLoc + pLoc->SizeOfBlock); } } //填充引入地址表 BOOL CMemLoadDll::FillRavAddress(void *pImageBase) { // 引入表实际上是一个 IMAGE_IMPORT_DESCRIPTOR 结构数组，全部是0表示结束 // 数组定义如下： // // DWORD OriginalFirstThunk; // 0表示结束，否则指向未绑定的IAT结构数组 // DWORD TimeDateStamp; // DWORD ForwarderChain; // -1 if no forwarders // DWORD Name; // 给出dll的名字 // DWORD FirstThunk; // 指向IAT结构数组的地址(绑定后，这些IAT里面就是实际的函数地址) unsigned long Offset = pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress ; if(Offset == 0) return TRUE; //No Import Table PIMAGE_IMPORT_DESCRIPTOR pID = (PIMAGE_IMPORT_DESCRIPTOR)((unsigned long) pImageBase + Offset); while(pID->Characteristics != 0 ) { PIMAGE_THUNK_DATA pRealIAT = (PIMAGE_THUNK_DATA)((unsigned long)pImageBase + pID->FirstThunk); PIMAGE_THUNK_DATA pOriginalIAT = (PIMAGE_THUNK_DATA)((unsigned long)pImageBase + pID->OriginalFirstThunk); //获取dll的名字 char buf[256]; //dll name; BYTE* pName = (BYTE*)((unsigned long)pImageBase + pID->Name); for(int i=0; i<256; i++) { if(pName[i] == 0)break; buf[i] = pName[i]; } if(i>=256) return FALSE; // bad dll name else buf[i] = 0; HMODULE hDll = GetModuleHandle(buf); if(hDll == NULL)return FALSE; //NOT FOUND DLL //获取DLL中每个导出函数的地址，填入IAT //每个IAT结构是 ： // union { PBYTE ForwarderString; // PDWORD Function; // DWORD Ordinal; // PIMAGE_IMPORT_BY_NAME AddressOfData; // } u1; // 长度是一个DWORD ，正好容纳一个地址。 for(i=0; ; i++) { if(pOriginalIAT[i].u1.Function == 0)break; FARPROC lpFunction = NULL; if(pOriginalIAT[i].u1.Ordinal & IMAGE_ORDINAL_FLAG) { //这里的值给出的是导出序号 lpFunction = GetProcAddress(hDll, (LPCSTR)(pOriginalIAT[i].u1.Ordinal & 0x0000FFFF)); } else { //按照名字导入 //获取此IAT项所描述的函数名称 PIMAGE_IMPORT_BY_NAME pByName = (PIMAGE_IMPORT_BY_NAME) ((DWORD)pImageBase + (DWORD)(pOriginalIAT[i].u1.AddressOfData)); // if(pByName->Hint !=0) // lpFunction = GetProcAddress(hDll, (LPCSTR)pByName->Hint); // else lpFunction = GetProcAddress(hDll, (char *)pByName->Name); } if(lpFunction != NULL) { //找到了！ pRealIAT[i].u1.Function = (PDWORD) lpFunction; } else return FALSE; } //move to next pID = (PIMAGE_IMPORT_DESCRIPTOR)( (DWORD)pID + sizeof(IMAGE_IMPORT_DESCRIPTOR)); } return TRUE; } //CheckDataValide函数用于检查缓冲区中的数据是否有效的dll文件 //返回值： 是一个可执行的dll则返回TRUE，否则返回FALSE。 //lpFileData: 存放dll数据的内存缓冲区 //DataLength: dll文件的长度 BOOL CMemLoadDll::CheckDataValide(void* lpFileData, int DataLength) { //检查长度 if(DataLength < sizeof(IMAGE_DOS_HEADER)) return FALSE; pDosHeader = (PIMAGE_DOS_HEADER)lpFileData; // DOS头 //检查dos头的标记 if(pDosHeader->e_magic != IMAGE_DOS_SIGNATURE) return FALSE; //0x5A4D : MZ //检查长度 if((DWORD)DataLength < (pDosHeader->e_lfanew + sizeof(IMAGE_NT_HEADERS)) ) return FALSE; //取得pe头 pNTHeader = (PIMAGE_NT_HEADERS)( (unsigned long)lpFileData + pDosHeader->e_lfanew); // PE头 //检查pe头的合法性 if(pNTHeader->Signature != IMAGE_NT_SIGNATURE) return FALSE; //0x00004550 : PE00 if((pNTHeader->FileHeader.Characteristics & IMAGE_FILE_DLL) == 0) //0x2000 : File is a DLL return FALSE; if((pNTHeader->FileHeader.Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE) == 0) //0x0002 : 指出文件可以运行 return FALSE; if(pNTHeader->FileHeader.SizeOfOptionalHeader != sizeof(IMAGE_OPTIONAL_HEADER)) return FALSE; //取得节表（段表） pSectionHeader = (PIMAGE_SECTION_HEADER)((int)pNTHeader + sizeof(IMAGE_NT_HEADERS)); //验证每个节表的空间 for(int i=0; i< pNTHeader->FileHeader.NumberOfSections; i++) { if((pSectionHeader[i].PointerToRawData + pSectionHeader[i].SizeOfRawData) > (DWORD)DataLength)return FALSE; } return TRUE; } //计算对齐边界 int CMemLoadDll::GetAlignedSize(int Origin, int Alignment) { return (Origin + Alignment - 1) / Alignment * Alignment; } //计算整个dll映像文件的尺寸 int CMemLoadDll::CalcTotalImageSize() { int Size; if(pNTHeader == NULL)return 0; int nAlign = pNTHeader->OptionalHeader.SectionAlignment; //段对齐字节数 // 计算所有头的尺寸。包括dos, coff, pe头 和 段表的大小 Size = GetAlignedSize(pNTHeader->OptionalHeader.SizeOfHeaders, nAlign); // 计算所有节的大小 for(int i=0; i < pNTHeader->FileHeader.NumberOfSections; ++i) { //得到该节的大小 int CodeSize = pSectionHeader[i].Misc.VirtualSize ; int LoadSize = pSectionHeader[i].SizeOfRawData; int MaxSize = (LoadSize > CodeSize)?(LoadSize):(CodeSize); int SectionSize = GetAlignedSize(pSectionHeader[i].VirtualAddress + MaxSize, nAlign); if(Size < SectionSize) Size = SectionSize; //Use the Max; } return Size; } //CopyDllDatas函数将dll数据复制到指定内存区域，并对齐所有节 //pSrc: 存放dll数据的原始缓冲区 //pDest:目标内存地址 void CMemLoadDll::CopyDllDatas(void* pDest, void* pSrc) { // 计算需要复制的PE头+段表字节数 int HeaderSize = pNTHeader->OptionalHeader.SizeOfHeaders; int SectionSize = pNTHeader->FileHeader.NumberOfSections * sizeof(IMAGE_SECTION_HEADER); int MoveSize = HeaderSize + SectionSize; //复制头和段信息 memmove(pDest, pSrc, MoveSize); //复制每个节 for(int i=0; i < pNTHeader->FileHeader.NumberOfSections; ++i) { if(pSectionHeader[i].VirtualAddress == 0 || pSectionHeader[i].SizeOfRawData == 0)continue; // 定位该节在内存中的位置 void *pSectionAddress = (void *)((unsigned long)pDest + pSectionHeader[i].VirtualAddress); // 复制段数据到虚拟内存 memmove((void *)pSectionAddress, (void *)((DWORD)pSrc + pSectionHeader[i].PointerToRawData), pSectionHeader[i].SizeOfRawData); } //修正指针，指向新分配的内存 //新的dos头 pDosHeader = (PIMAGE_DOS_HEADER)pDest; //新的pe头地址 pNTHeader = (PIMAGE_NT_HEADERS)((int)pDest + (pDosHeader->e_lfanew)); //新的节表地址 pSectionHeader = (PIMAGE_SECTION_HEADER)((int)pNTHeader + sizeof(IMAGE_NT_HEADERS)); return ; }
