Fltsendmessage & fltgetmessage issues

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C

.NET

I was pretty sure at the time my issue with this was figured out but I am running into some pretty crazy errors with accessing protected memory and what not that I am unable to pin down to the source cause. At the moment I am able to build my mini filter driver with no errors, my user application is in vb.net this is were it gets complicated further but I am almost there also.

my driver code is:

ULONG PROC_TAG = 0;
						UNICODE_STRING processName;

						processName.Length = 0;
						processName.MaximumLength = (USHORT)DoSPath.MaximumLength + Data->Iopb->TargetFileObject->FileName.MaximumLength + 2;
						processName.Buffer = ExAllocatePoolWithTag(PagedPool, processName.MaximumLength, PROC_TAG);

						RtlCopyUnicodeString(&processName, &DoSPath);
						RtlAppendUnicodeStringToString(&processName, &Data->Iopb->TargetFileObject->FileName);

						KdPrint(("%wZ \r\n", processName));
						RtlCopyUnicodeString(&ImageP, &processName);

						if (SendClientPort) {
							USHORT nameLen = processName.Length;
							USHORT len = sizeof(processName.MaximumLength) + nameLen;
							processName.Buffer = ExAllocatePoolWithTag(PagedPool, len, PROC_TAG);
							if (processName.Buffer) {
								RtlCopyMemory(processName.Buffer, processName.Buffer, nameLen);
								LARGE_INTEGER timeout;
								timeout.QuadPart = -10000 * 100;
								FltSendMessage(FilterHandle, &SendClientPort, processName.Buffer, len, NULL, NULL, &timeout);
							}
						}

And the code in vb.net is like this

What I have tried:

<StructLayout(LayoutKind.Sequential)>
    Public Structure FILTER_MESSAGE_HEADER
        Public ReplyLength As UInteger
        Public MessageId As ULong
    End Structure

Public Structure DATA_RECEIVE
       Public messageHeader As FILTER_MESSAGE_HEADER
       <MarshalAs(UnmanagedType.ByValArray, SizeConst:=BUFFER_SIZE)>
       Public messageContent As Byte()
   End Structure

<DllImport("fltlib.dll")>
    Public Shared Function FilterConnectCommunicationPort(<MarshalAs(UnmanagedType.LPWStr)>
                                                          portName As String,
                                                          options As UInteger,
                                                          context As IntPtr,
                                                          sizeOfContext As UInteger,
                                                          securityAttributes As IntPtr,
                                                          <Out> ByRef portHandle As SafeFileHandle) As UInteger

    End Function

<DllImport("fltlib.dll")>
  Public Shared Function FilterGetMessage(portHandle As SafeFileHandle,
                                          ByRef messageBuffer As FILTER_MESSAGE_HEADER,
                                          messageBufferSize As Integer,
                                          overlapped As IntPtr) As UInteger

  End Function

Dim OpenPortStatus = FilterConnectCommunicationPort("\BitPort", 0, Nothing, 0, Nothing, OpenPortHandle)
        MsgBox("Open Communication Port Status: " & OpenPortStatus & " Port Number: " & OpenPortHandle.DangerousGetHandle.ToString)

        Dim dataReceive As DATA_RECEIVE = New DATA_RECEIVE()
        dataReceive.messageContent = New Byte(BUFFER_SIZE - 1) {}
        Dim headerSize As Integer = Marshal.SizeOf(dataReceive.messageHeader)
        Dim dataSize As Integer = BUFFER_SIZE + headerSize

        Dim status = FilterGetMessage(OpenPortHandle, dataReceive.messageHeader, dataSize, IntPtr.Zero)
        If status = 0 Then
            Dim message As String = Encoding.Unicode.GetString(dataReceive.messageContent)
            MsgBox(message)
        End If

Thank you for taking a look I am seriously stuck as to why I get no message or I always get a access violation.