在笔者上篇文章《驱动开发:内核扫描SSDT挂钩状态》
中简单介绍了如何扫描被挂钩的SSDT函数,并简单介绍了如何解析导出表,本章将继续延申PE导出表的解析,实现一系列灵活的解析如通过传入函数名解析出函数的RVA偏移,ID索引,Index下标等参数,并将其封装为可直接使用的函数,以在后期需要时可以被直接引用,同样为了节约篇幅本章中的LoadKernelFile()
内存映射函数如需要使用请去前一篇文章中自行摘取。
首先实现GetRvaFromModuleName()
函数,当用户传入参数后自动将函数名解析为对应的RVA偏移或Index下标索引值,该函数接收三个参数传递,分别是wzFileName
模块名,FunctionName
所在模块内的函数名,Flag
标志参数,函数输出ULONG64
类型的数据。
// 署名权 // right to sign one's name on a piece of work // PowerBy: LyShark // Email: me@lyshark.com // 从指定模块中得到特定函数的RVA或相对序号相对偏移 ULONG64 GetRvaFromModuleName(WCHAR *wzFileName, UCHAR *FunctionName, INT Flag) { // 加载内核模块 PVOID BaseAddress = LoadKernelFile(wzFileName); // 取出导出表 PIMAGE_DOS_HEADER pDosHeader; PIMAGE_NT_HEADERS pNtHeaders; PIMAGE_SECTION_HEADER pSectionHeader; ULONGLONG FileOffset; PIMAGE_EXPORT_DIRECTORY pExportDirectory; // DLL内存数据转成DOS头结构 pDosHeader = (PIMAGE_DOS_HEADER)BaseAddress; // 取出PE头结构 pNtHeaders = (PIMAGE_NT_HEADERS)((ULONGLONG)BaseAddress + pDosHeader->e_lfanew); // 判断PE头导出表是否为空 if (pNtHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress == 0) { return 0; } // 取出导出表偏移 FileOffset = pNtHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress; // 取出节头结构 pSectionHeader = (PIMAGE_SECTION_HEADER)((ULONGLONG)pNtHeaders + sizeof(IMAGE_NT_HEADERS)); PIMAGE_SECTION_HEADER pOldSectionHeader = pSectionHeader; // 遍历节结构进行地址运算 for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } // 导出表地址 pExportDirectory = (PIMAGE_EXPORT_DIRECTORY)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数地址 PULONG AddressOfFunctions; FileOffset = pExportDirectory->AddressOfFunctions; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfFunctions = (PULONG)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数名字 PUSHORT AddressOfNameOrdinals; FileOffset = pExportDirectory->AddressOfNameOrdinals; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfNameOrdinals = (PUSHORT)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数序号 PULONG AddressOfNames; FileOffset = pExportDirectory->AddressOfNames; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfNames = (PULONG)((ULONGLONG)BaseAddress + FileOffset); // 分析导出表 ULONG uOffset; LPSTR FunName; ULONG uAddressOfNames; ULONG TargetOff = 0; for (ULONG uIndex = 0; uIndex < pExportDirectory->NumberOfNames; uIndex++, AddressOfNames++, AddressOfNameOrdinals++) { uAddressOfNames = *AddressOfNames; pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= uAddressOfNames && uAddressOfNames <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { uOffset = uAddressOfNames - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } FunName = (LPSTR)((ULONGLONG)BaseAddress + uOffset); // 如果找到则返回RVA if (!_stricmp((const char *)FunctionName, FunName)) { // 等于1则返回RVA if (Flag == 1) { TargetOff = (ULONG)AddressOfFunctions[*AddressOfNameOrdinals]; // DbgPrint("索引 [ %p ] 函数名 [ %s ] 相对RVA [ %p ] \n", *AddressOfNameOrdinals, FunName, TargetOff); return TargetOff; } // 返回索引 else if (Flag == 0) { return *AddressOfNameOrdinals; } } } // 结束后释放内存 ExFreePoolWithTag(BaseAddress, (ULONG)"LyShark"); return 0; }
调用该函数很容易,传入模块路径以及该模块内的函数名,解析出RVA地址或Index下标。
NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath) { // 函数分别传入 [模块路径,函数名,标志=1] 返回该导出函数的RVA ULONG64 get_rva = GetRvaFromModuleName(L"\\SystemRoot\\system32\\ntoskrnl.exe", "NtReadFile", 1); DbgPrint("NtReadFile RVA = %p \n", get_rva); // 函数分别传入 [模块路径,函数名,标志=0] 返回该导出函数的ID下标 ULONG64 get_id = GetRvaFromModuleName(L"\\SystemRoot\\system32\\ntoskrnl.exe", "NtReadFile", 0); DbgPrint("NtReadFile ID = %d \n", get_id); Driver->DriverUnload = UnDriver; return STATUS_SUCCESS; }
编译并运行程序,分别获取到ntoskrnl.exe
模块内NtReadFile
函数的RVA,Index索引,调用效果如下;
第二个函数GetModuleNameFromRVA()
则实现传入RVA或者函数Index序号,解析出函数名,具体实现方法与如上函数基本一致,仅仅只是在过滤时做了调整。
// 署名权 // right to sign one's name on a piece of work // PowerBy: LyShark // Email: me@lyshark.com // 根据传入的函数RVA或Index下标,获取该函数的函数名 PCHAR GetModuleNameFromRVA(WCHAR *wzFileName, ULONG64 uRVA, INT Flag) { // 加载内核模块 PVOID BaseAddress = LoadKernelFile(wzFileName); // 取出导出表 PIMAGE_DOS_HEADER pDosHeader; PIMAGE_NT_HEADERS pNtHeaders; PIMAGE_SECTION_HEADER pSectionHeader; ULONGLONG FileOffset; PIMAGE_EXPORT_DIRECTORY pExportDirectory; // DLL内存数据转成DOS头结构 pDosHeader = (PIMAGE_DOS_HEADER)BaseAddress; // 取出PE头结构 pNtHeaders = (PIMAGE_NT_HEADERS)((ULONGLONG)BaseAddress + pDosHeader->e_lfanew); // 判断PE头导出表是否为空 if (pNtHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress == 0) { return 0; } // 取出导出表偏移 FileOffset = pNtHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress; // 取出节头结构 pSectionHeader = (PIMAGE_SECTION_HEADER)((ULONGLONG)pNtHeaders + sizeof(IMAGE_NT_HEADERS)); PIMAGE_SECTION_HEADER pOldSectionHeader = pSectionHeader; // 遍历节结构进行地址运算 for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } // 导出表地址 pExportDirectory = (PIMAGE_EXPORT_DIRECTORY)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数地址 PULONG AddressOfFunctions; FileOffset = pExportDirectory->AddressOfFunctions; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfFunctions = (PULONG)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数名字 PUSHORT AddressOfNameOrdinals; FileOffset = pExportDirectory->AddressOfNameOrdinals; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfNameOrdinals = (PUSHORT)((ULONGLONG)BaseAddress + FileOffset); // 取出导出表函数序号 PULONG AddressOfNames; FileOffset = pExportDirectory->AddressOfNames; // 遍历节结构进行地址运算 pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= FileOffset && FileOffset <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { FileOffset = FileOffset - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } AddressOfNames = (PULONG)((ULONGLONG)BaseAddress + FileOffset); // 分析导出表 ULONG uOffset; LPSTR FunName; ULONG uAddressOfNames; ULONG TargetOff = 0; for (ULONG uIndex = 0; uIndex < pExportDirectory->NumberOfNames; uIndex++, AddressOfNames++, AddressOfNameOrdinals++) { uAddressOfNames = *AddressOfNames; pSectionHeader = pOldSectionHeader; for (UINT16 Index = 0; Index < pNtHeaders->FileHeader.NumberOfSections; Index++, pSectionHeader++) { if (pSectionHeader->VirtualAddress <= uAddressOfNames && uAddressOfNames <= pSectionHeader->VirtualAddress + pSectionHeader->SizeOfRawData) { uOffset = uAddressOfNames - pSectionHeader->VirtualAddress + pSectionHeader->PointerToRawData; } } FunName = (LPSTR)((ULONGLONG)BaseAddress + uOffset); TargetOff = (ULONG)AddressOfFunctions[*AddressOfNameOrdinals]; // 等于1则通过RVA返回函数名 if (Flag == 1) { if (uRVA == TargetOff) { return FunName; } } // 返回索引 else if (Flag == 0) { if (uRVA == *AddressOfNameOrdinals) { return FunName; } } } // 结束后释放内存 ExFreePoolWithTag(BaseAddress, (ULONG)"LyShark"); return "None"; }
调用GetModuleNameFromRVA()
并传入相应的RVA偏移或Index下标。
NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath) { DbgPrint("hello lyshark.com \n"); PCHAR function_name; // 传入函数RVA得到函数名 function_name = GetModuleNameFromRVA(L"\\SystemRoot\\system32\\ntoskrnl.exe", 0x5e5220, 1); DbgPrint("根据RVA得到函数名 = %s \n", function_name); // 传入函数下标得到函数名 function_name = GetModuleNameFromRVA(L"\\SystemRoot\\system32\\ntoskrnl.exe", 1472, 0); DbgPrint("根据Index得到函数名 = %s \n", function_name); Driver->DriverUnload = UnDriver; return STATUS_SUCCESS; }
编译并运行程序,调用后分别获取到RVA=0x5e5220
或Index=1472
的函数名;