本篇文章与上一篇文章《驱动开发：内核注册并监控对象回调》所使用的方式是一样的都是使用ObRegisterCallbacks注册回调事件，只不过上一篇博文中LyShark将回调结构体OB_OPERATION_REGISTRATION中的ObjectType填充为了PsProcessType和PsThreadType格式从而实现监控进程与线程，本章我们需要将该结构填充为IoFileObjectType以此来实现对文件的监控，文件过滤驱动不仅仅可以用来监控文件的打开，还可以用它实现对文件的保护，一旦驱动加载则文件是不可被删除和改动的。
与进程线程回调有少许的不同，文件回调需要开启驱动的TypeInfo.SupportsObjectCallbacks开关，并定义一些微软结构，如下是我们所需要的公开结构体，可在微软官方或WinDBG中获取到最新的，将其保存为lyshark.h方便后期引用。
// 署名权 // right to sign one's name on a piece of work // PowerBy: LyShark // Email: me@lyshark.com #include <ntddk.h> #include <ntstrsafe.h> typedef struct _CALLBACK_ENTRY { LIST_ENTRY CallbackList; OB_OPERATION Operations; ULONG Active; PVOID Handle; POBJECT_TYPE ObjectType; POB_PRE_OPERATION_CALLBACK PreOperation; POB_POST_OPERATION_CALLBACK PostOperation; ULONG unknown; } CALLBACK_ENTRY, *PCALLBACK_ENTRY; typedef struct _LDR_DATA // 24 elements, 0xE0 bytes (sizeof) { /*0x000*/ struct _LIST_ENTRY InLoadOrderLinks; // 2 elements, 0x10 bytes (sizeof) /*0x010*/ struct _LIST_ENTRY InMemoryOrderLinks; // 2 elements, 0x10 bytes (sizeof) /*0x020*/ struct _LIST_ENTRY InInitializationOrderLinks; // 2 elements, 0x10 bytes (sizeof) /*0x030*/ VOID* DllBase; /*0x038*/ VOID* EntryPoint; /*0x040*/ ULONG32 SizeOfImage; /*0x044*/ UINT8 _PADDING0_[0x4]; /*0x048*/ struct _UNICODE_STRING FullDllName; // 3 elements, 0x10 bytes (sizeof) /*0x058*/ struct _UNICODE_STRING BaseDllName; // 3 elements, 0x10 bytes (sizeof) /*0x068*/ ULONG32 Flags; /*0x06C*/ UINT16 LoadCount; /*0x06E*/ UINT16 TlsIndex; union // 2 elements, 0x10 bytes (sizeof) { /*0x070*/ struct _LIST_ENTRY HashLinks; // 2 elements, 0x10 bytes (sizeof) struct // 2 elements, 0x10 bytes (sizeof) { /*0x070*/ VOID* SectionPointer; /*0x078*/ ULONG32 CheckSum; /*0x07C*/ UINT8 _PADDING1_[0x4]; }; }; union // 2 elements, 0x8 bytes (sizeof) { /*0x080*/ ULONG32 TimeDateStamp; /*0x080*/ VOID* LoadedImports; }; /*0x088*/ struct _ACTIVATION_CONTEXT* EntryPointActivationContext; /*0x090*/ VOID* PatchInformation; /*0x098*/ struct _LIST_ENTRY ForwarderLinks; // 2 elements, 0x10 bytes (sizeof) /*0x0A8*/ struct _LIST_ENTRY ServiceTagLinks; // 2 elements, 0x10 bytes (sizeof) /*0x0B8*/ struct _LIST_ENTRY StaticLinks; // 2 elements, 0x10 bytes (sizeof) /*0x0C8*/ VOID* ContextInformation; /*0x0D0*/ UINT64 OriginalBase; /*0x0D8*/ union _LARGE_INTEGER LoadTime; // 4 elements, 0x8 bytes (sizeof) }LDR_DATA, *PLDR_DATA; typedef struct _OBJECT_TYPE_INITIALIZER // 25 elements, 0x70 bytes (sizeof) { /*0x000*/ UINT16 Length; union // 2 elements, 0x1 bytes (sizeof) { /*0x002*/ UINT8 ObjectTypeFlags; struct // 7 elements, 0x1 bytes (sizeof) { /*0x002*/ UINT8 CaseInsensitive : 1; // 0 BitPosition /*0x002*/ UINT8 UnnamedObjectsOnly : 1; // 1 BitPosition /*0x002*/ UINT8 UseDefaultObject : 1; // 2 BitPosition /*0x002*/ UINT8 SecurityRequired : 1; // 3 BitPosition /*0x002*/ UINT8 MaintainHandleCount : 1; // 4 BitPosition /*0x002*/ UINT8 MaintainTypeList : 1; // 5 BitPosition /*0x002*/ UINT8 SupportsObjectCallbacks : 1; // 6 BitPosition }; }; /*0x004*/ ULONG32 ObjectTypeCode; /*0x008*/ ULONG32 InvalidAttributes; /*0x00C*/ struct _GENERIC_MAPPING GenericMapping; // 4 elements, 0x10 bytes (sizeof) /*0x01C*/ ULONG32 ValidAccessMask; /*0x020*/ ULONG32 RetainAccess; /*0x024*/ enum _POOL_TYPE PoolType; /*0x028*/ ULONG32 DefaultPagedPoolCharge; /*0x02C*/ ULONG32 DefaultNonPagedPoolCharge; /*0x030*/ PVOID DumpProcedure; /*0x038*/ PVOID OpenProcedure; /*0x040*/ PVOID CloseProcedure; /*0x048*/ PVOID DeleteProcedure; /*0x050*/ PVOID ParseProcedure; /*0x058*/ PVOID SecurityProcedure; /*0x060*/ PVOID QueryNameProcedure; /*0x068*/ PVOID OkayToCloseProcedure; }OBJECT_TYPE_INITIALIZER, *POBJECT_TYPE_INITIALIZER; typedef struct _EX_PUSH_LOCK // 7 elements, 0x8 bytes (sizeof) { union // 3 elements, 0x8 bytes (sizeof) { struct // 5 elements, 0x8 bytes (sizeof) { /*0x000*/ UINT64 Locked : 1; // 0 BitPosition /*0x000*/ UINT64 Waiting : 1; // 1 BitPosition /*0x000*/ UINT64 Waking : 1; // 2 BitPosition /*0x000*/ UINT64 MultipleShared : 1; // 3 BitPosition /*0x000*/ UINT64 Shared : 60; // 4 BitPosition }; /*0x000*/ UINT64 Value; /*0x000*/ VOID* Ptr; }; }EX_PUSH_LOCK, *PEX_PUSH_LOCK; typedef struct _MY_OBJECT_TYPE // 12 elements, 0xD0 bytes (sizeof) { /*0x000*/ struct _LIST_ENTRY TypeList; // 2 elements, 0x10 bytes (sizeof) /*0x010*/ struct _UNICODE_STRING Name; // 3 elements, 0x10 bytes (sizeof) /*0x020*/ VOID* DefaultObject; /*0x028*/ UINT8 Index; /*0x029*/ UINT8 _PADDING0_[0x3]; /*0x02C*/ ULONG32 TotalNumberOfObjects; /*0x030*/ ULONG32 TotalNumberOfHandles; /*0x034*/ ULONG32 HighWaterNumberOfObjects; /*0x038*/ ULONG32 HighWaterNumberOfHandles; /*0x03C*/ UINT8 _PADDING1_[0x4]; /*0x040*/ struct _OBJECT_TYPE_INITIALIZER TypeInfo; // 25 elements, 0x70 bytes (sizeof) /*0x0B0*/ struct _EX_PUSH_LOCK TypeLock; // 7 elements, 0x8 bytes (sizeof) /*0x0B8*/ ULONG32 Key; /*0x0BC*/ UINT8 _PADDING2_[0x4]; /*0x0C0*/ struct _LIST_ENTRY CallbackList; // 2 elements, 0x10 bytes (sizeof) }MY_OBJECT_TYPE, *PMY_OBJECT_TYPE; 对于开启了TypeInfo.SupportsObjectCallbacks属性的驱动来说自然就支持文件路径转换，当系统中有文件被加载则自动执行LySharkFileObjectpreCall回调事件，过滤掉无效路径后即可直接输出，完整代码如下所示；
// 署名权 // right to sign one's name on a piece of work // PowerBy: LyShark // Email: me@lyshark.com #include "lyshark.h" PVOID obHandle; DRIVER_INITIALIZE DriverEntry; // 文件回调 OB_PREOP_CALLBACK_STATUS LySharkFileObjectpreCall(PVOID RegistrationContext, POB_PRE_OPERATION_INFORMATION OperationInformation) { UNICODE_STRING DosName; PFILE_OBJECT fileo = OperationInformation->Object; HANDLE CurrentProcessId = PsGetCurrentProcessId(); UNREFERENCED_PARAMETER(RegistrationContext); if (OperationInformation->ObjectType != *IoFileObjectType) { return OB_PREOP_SUCCESS; } // 过滤无效指针 if (fileo->FileName.Buffer == NULL || !MmIsAddressValid(fileo->FileName.Buffer) || fileo->DeviceObject == NULL || !MmIsAddressValid(fileo->DeviceObject)) { return OB_PREOP_SUCCESS; } // 过滤无效路径 if (!_wcsicmp(fileo->FileName.Buffer, L"\Endpoint") || !_wcsicmp(fileo->FileName.Buffer, L"?") || !_wcsicmp(fileo->FileName.Buffer, L"\.\.") || !_wcsicmp(fileo->FileName.Buffer, L"\")) { return OB_PREOP_SUCCESS; } // 将对象转为DOS路径 RtlVolumeDeviceToDosName(fileo->DeviceObject, &DosName); DbgPrint("[LyShark] 进程PID = %ld | 文件路径 = %wZ%wZ n", (ULONG64)CurrentProcessId, &DosName, &fileo->FileName); return OB_PREOP_SUCCESS; } VOID EnableObType(POBJECT_TYPE ObjectType) { PMY_OBJECT_TYPE myobtype = (PMY_OBJECT_TYPE)ObjectType; myobtype->TypeInfo.SupportsObjectCallbacks = 1; } VOID UnDriver(PDRIVER_OBJECT driver) { UNREFERENCED_PARAMETER(driver); ObUnRegisterCallbacks(obHandle); } NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath) { NTSTATUS status = STATUS_SUCCESS; PLDR_DATA ldr; DbgPrint("hello lyshark.com n"); OB_CALLBACK_REGISTRATION obRegFileCallBack; OB_OPERATION_REGISTRATION opRegFileCallBack; // enable IoFileObjectType EnableObType(*IoFileObjectType); // bypass MmVerifyCallbackFunction ldr = (PLDR_DATA)Driver->DriverSection; ldr->Flags |= 0x20; // 初始化回调 memset(&obRegFileCallBack, 0, sizeof(obRegFileCallBack)); obRegFileCallBack.Version = ObGetFilterVersion(); obRegFileCallBack.OperationRegistrationCount = 1; obRegFileCallBack.RegistrationContext = NULL; RtlInitUnicodeString(&obRegFileCallBack.Altitude, L"321000"); obRegFileCallBack.OperationRegistration = &opRegFileCallBack; memset(&opRegFileCallBack, 0, sizeof(opRegFileCallBack)); opRegFileCallBack.ObjectType = IoFileObjectType; opRegFileCallBack.Operations = OB_OPERATION_HANDLE_CREATE | OB_OPERATION_HANDLE_DUPLICATE; opRegFileCallBack.PreOperation = (POB_PRE_OPERATION_CALLBACK)&LySharkFileObjectpreCall; status = ObRegisterCallbacks(&obRegFileCallBack, &obHandle); if (!NT_SUCCESS(status)) { DbgPrint("注册回调错误 n"); status = STATUS_UNSUCCESSFUL; } UNREFERENCED_PARAMETER(RegistryPath); Driver->DriverUnload = &UnDriver; return status; } 运行这个驱动程序，当系统中有新文件被加载时则自动输出该文件所属进程PID以及该文件的详细路径。
至于如何阻止打开一个文件其实与《驱动开发：内核注册并监控对象回调》文章中使用的方法是一致的，首先判断OperationInformation->Operation是不是OB_OPERATION_HANDLE_CREATE或OB_OPERATION_HANDLE_DUPLICATE如果是，则直接设置Parameters->CreateHandleInformation.DesiredAccess为0直接拒绝加载。
// 文件回调 OB_PREOP_CALLBACK_STATUS LySharkFileObjectpreCall(PVOID RegistrationContext, POB_PRE_OPERATION_INFORMATION OperationInformation) { UNICODE_STRING DosName; PFILE_OBJECT fileo = OperationInformation->Object; HANDLE CurrentProcessId = PsGetCurrentProcessId(); UNREFERENCED_PARAMETER(RegistrationContext); if (OperationInformation->ObjectType != *IoFileObjectType) { return OB_PREOP_SUCCESS; } // 过滤无效指针 if (fileo->FileName.Buffer == NULL || !MmIsAddressValid(fileo->FileName.Buffer) || fileo->DeviceObject == NULL || !MmIsAddressValid(fileo->DeviceObject)) { return OB_PREOP_SUCCESS; } // 过滤无效路径 if (!_wcsicmp(fileo->FileName.Buffer, L"\Endpoint") || !_wcsicmp(fileo->FileName.Buffer, L"?") || !_wcsicmp(fileo->FileName.Buffer, L"\.\.") || !_wcsicmp(fileo->FileName.Buffer, L"\")) { return OB_PREOP_SUCCESS; } // 阻止打开lyshark_com.txt文本 if (wcsstr(_wcslwr(fileo->FileName.Buffer), L"lyshark_com.txt")) { if (OperationInformation->Operation == OB_OPERATION_HANDLE_CREATE) { OperationInformation->Parameters->CreateHandleInformation.DesiredAccess = 0; } if (OperationInformation->Operation == OB_OPERATION_HANDLE_DUPLICATE) { OperationInformation->Parameters->DuplicateHandleInformation.DesiredAccess = 0; } DbgPrint("[LyShark] 已拦截 lyshark_com 文件打开 n"); } return OB_PREOP_SUCCESS; } 运行修改后的驱动程序，然后尝试打开lyshark_com.txt则会提示系统找不到指定文件。
