从C#代码中使用DeviceIoControl总是返回空的输出缓冲区

Question

我有一个驱动程序，我想从我的C#客户端应用程序中使用它。这里的问题是我的输出缓冲区总是空的(0(。当我从C代码中使用这个驱动程序时，一切都像一个魅力，所以我认为问题出在我的客户端C#代码中。

Extern定义如下：

[DllImport(kernel, EntryPoint = "DeviceIoControl", SetLastError = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool DeviceIoControl(
SafeFileHandle hDevice,
UInt32 dwIoControlCode,
IntPtr lpInBuffer,
UInt32 nInBufferSize,
IntPtr lpOutBuffer,
UInt32 nOutBufferSize,
ref UInt32 lpBytesReturned,
[In] ref NativeOverlapped lpOverlapped);

我用它作为：

public static T ReadVirtualMemory<T>(SafeFileHandle driverHandle, int offset) where T : unmanaged
{
var inBuffer = (object)new T();
var nInBufferSize = Marshal.SizeOf(typeof(T));
var outBuffer = (object)new T();
var nOutBufferSize = Marshal.SizeOf(typeof(T));
var data = new KERNEL_READ_REQUEST
{
Address = (ulong)offset,
Size = (ulong)nInBufferSize,
pBuffer = (IntPtr)inBuffer
};
IntPtr lpInBuffer = IntPtr.Zero;
IntPtr lpOutBuffer = IntPtr.Zero;
nInBufferSize = Marshal.SizeOf(data);
lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
Marshal.StructureToPtr(data, lpInBuffer, true);
lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);
Marshal.StructureToPtr(outBuffer, lpOutBuffer, true);
UInt32 lpBytesReturned = 0;
NativeOverlapped lpOverlapped = new NativeOverlapped();
Kernel32.DeviceIoControl(
driverHandle,
(uint)DriverMethod.ReadMemory,
lpInBuffer,
(uint)nInBufferSize,
lpOutBuffer,
(uint)nOutBufferSize,
ref lpBytesReturned,
ref lpOverlapped);
outBuffer = (T)Marshal.PtrToStructure(lpOutBuffer, typeof(T));
return lpBytesReturned == nOutBufferSize ? (T)outBuffer : default;
}

我不知道为什么，返回的字节数=8，尽管应该是4。正如我所说的，out缓冲区是空的。Drver代码：

PKERNEL_READ_REQUEST readRequest = (PKERNEL_READ_REQUEST)pIrp->AssociatedIrp.SystemBuffer;
PEPROCESS process;
if (NT_SUCCESS(PsLookupProcessByProcessId(ProcessId, &process)))
{
DebugMessage("ReadRequest requestedn");
KernelReadVirtualMemory(process, readRequest->Address, readRequest->pBuffer, readRequest->Size);
byteIo = sizeof(PKERNEL_READ_REQUEST);
status = STATUS_SUCCESS;
}

和

NTSTATUS NTAPI MmCopyVirtualMemory
(
PEPROCESS SourceProcess,
PVOID SourceAddress,
PEPROCESS TargetProcess,
PVOID TargetAddress,
SIZE_T BufferSize,
KPROCESSOR_MODE PreviousMode,
PSIZE_T ReturnSize
);
NTSTATUS KernelReadVirtualMemory(PEPROCESS process, PVOID sourceAddress, PVOID targetAddress, SIZE_T size)
{
PSIZE_T bytes;
return MmCopyVirtualMemory(process, sourceAddress, PsGetCurrentProcess(), targetAddress, size, KernelMode, &bytes);
}

这可能是关于结构对齐的smth，但我不确定(在C客户端应用程序中，结构的大小是18字节，在C#中是32字节(。

请告知

Answer 1

首先-我必须在x64中编译。第二个-必须为pBuffer 分配内存

以下是的工作示例

var nInBufferSize = Marshal.SizeOf(typeof(T));
var inBuffer = Marshal.AllocHGlobal(nInBufferSize);
var data = new KERNEL_READ_REQUEST
{
Address = offset,
Size = nInBufferSize,
pBuffer = inBuffer
};
var requestSize = Marshal.SizeOf(data);
var requestBuffer = Marshal.AllocHGlobal(requestSize);
Marshal.StructureToPtr(data, requestBuffer, true);
uint bytesReturned = 0;
var overlapped = new NativeOverlapped();
Kernel32.DeviceIoControl(
driverHandle,
(uint)DriverMethod.ReadMemory,
requestBuffer,
(uint)requestSize,
requestBuffer,
(uint)requestSize,
ref bytesReturned,
ref overlapped);
var result = Marshal.PtrToStructure(data.pBuffer, typeof(T));
return (T?)result ?? default;