server/remdesk_main.c

 
#include <freerdp/config.h>
 
#include <winpr/crt.h>
#include <winpr/print.h>
#include <winpr/stream.h>
 
#include <freerdp/freerdp.h>
 
#include "remdesk_main.h"
#include "remdesk_common.h"
 
WINPR_ATTR_NODISCARD
static UINT remdesk_virtual_channel_write(RemdeskServerContext* context, wStream* s)
{
  const size_t len = Stream_Length(s);
  WINPR_ASSERT(len <= UINT32_MAX);
  ULONG BytesWritten = 0;
  BOOL status = WTSVirtualChannelWrite(context->priv->ChannelHandle, Stream_BufferAs(s, char),
                                       (UINT32)len, &BytesWritten);
  return (status) ? CHANNEL_RC_OK : ERROR_INTERNAL_ERROR;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_send_ctl_result_pdu(RemdeskServerContext* context, UINT32 result)
{
  wStream* s = nullptr;
  REMDESK_CTL_RESULT_PDU pdu;
  UINT error = 0;
  pdu.result = result;
 
  if ((error = remdesk_prepare_ctl_header(&(pdu.ctlHeader), REMDESK_CTL_RESULT, 4)))
  {
    WLog_ERR(TAG, "remdesk_prepare_ctl_header failed with error %" PRIu32 "!", error);
    return error;
  }
 
  s = Stream_New(nullptr, REMDESK_CHANNEL_CTL_SIZE + pdu.ctlHeader.ch.DataLength);
 
  if (!s)
  {
    WLog_ERR(TAG, "Stream_New failed!");
    return CHANNEL_RC_NO_MEMORY;
  }
 
  if ((error = remdesk_write_ctl_header(s, &(pdu.ctlHeader))))
  {
    WLog_ERR(TAG, "remdesk_write_ctl_header failed with error %" PRIu32 "!", error);
    goto out;
  }
 
  Stream_Write_UINT32(s, pdu.result); /* result (4 bytes) */
  Stream_SealLength(s);
 
  if ((error = remdesk_virtual_channel_write(context, s)))
    WLog_ERR(TAG, "remdesk_virtual_channel_write failed with error %" PRIu32 "!", error);
 
out:
  Stream_Free(s, TRUE);
  return error;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_send_ctl_version_info_pdu(RemdeskServerContext* context)
{
  wStream* s = nullptr;
  REMDESK_CTL_VERSION_INFO_PDU pdu;
  UINT error = 0;
 
  if ((error = remdesk_prepare_ctl_header(&(pdu.ctlHeader), REMDESK_CTL_VERSIONINFO, 8)))
  {
    WLog_ERR(TAG, "remdesk_prepare_ctl_header failed with error %" PRIu32 "!", error);
    return error;
  }
 
  pdu.versionMajor = 1;
  pdu.versionMinor = 2;
  s = Stream_New(nullptr, REMDESK_CHANNEL_CTL_SIZE + pdu.ctlHeader.ch.DataLength);
 
  if (!s)
  {
    WLog_ERR(TAG, "Stream_New failed!");
    return CHANNEL_RC_NO_MEMORY;
  }
 
  if ((error = remdesk_write_ctl_header(s, &(pdu.ctlHeader))))
  {
    WLog_ERR(TAG, "remdesk_write_ctl_header failed with error %" PRIu32 "!", error);
    goto out;
  }
 
  Stream_Write_UINT32(s, pdu.versionMajor); /* versionMajor (4 bytes) */
  Stream_Write_UINT32(s, pdu.versionMinor); /* versionMinor (4 bytes) */
  Stream_SealLength(s);
 
  if ((error = remdesk_virtual_channel_write(context, s)))
    WLog_ERR(TAG, "remdesk_virtual_channel_write failed with error %" PRIu32 "!", error);
 
out:
  Stream_Free(s, TRUE);
  return error;
}
 
WINPR_ATTR_NODISCARD
static UINT
remdesk_recv_ctl_version_info_pdu(WINPR_ATTR_UNUSED RemdeskServerContext* context, wStream* s,
                                  WINPR_ATTR_UNUSED const REMDESK_CHANNEL_HEADER* header)
{
  UINT32 versionMajor = 0;
  UINT32 versionMinor = 0;
 
  if (header->DataLength < 12ull)
  {
    WLog_ERR(TAG, "remdesk: HEADER::DataLength=%" PRIu32 ", but expected >= 12",
             header->DataLength);
    return ERROR_INVALID_DATA;
  }
 
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 8))
    return ERROR_INVALID_DATA;
 
  Stream_Read_UINT32(s, versionMajor); /* versionMajor (4 bytes) */
  Stream_Read_UINT32(s, versionMinor); /* versionMinor (4 bytes) */
  if ((versionMajor != 1) || (versionMinor != 2))
  {
    WLog_ERR(TAG, "REMOTEDESKTOP_CTL_VERSIONINFO_PACKET invalid version %" PRIu32 ".%" PRIu32,
             versionMajor, versionMinor);
    return ERROR_INVALID_DATA;
  }
 
  return CHANNEL_RC_OK;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_recv_ctl_remote_control_desktop_pdu(RemdeskServerContext* context, wStream* s,
                                                        const REMDESK_CHANNEL_HEADER* header)
{
  size_t cchStringW = 0;
  REMDESK_CTL_REMOTE_CONTROL_DESKTOP_PDU pdu = WINPR_C_ARRAY_INIT;
  UINT error = 0;
 
  size_t cchMax = header->DataLength - 4ull;
  const size_t remaining = Stream_GetRemainingLength(s);
  if (cchMax > remaining)
    cchMax = remaining;
  cchMax /= sizeof(WCHAR);
 
  const WCHAR* pStringW = Stream_ConstPointer(s);
  const WCHAR* raConnectionStringW = pStringW;
 
  while ((cchStringW < cchMax) && pStringW[cchStringW])
    cchStringW++;
 
  if ((cchStringW >= cchMax) || !cchStringW)
    return ERROR_INVALID_DATA;
 
  cchStringW++;
  const size_t cbRaConnectionStringW = cchStringW * sizeof(WCHAR);
  pdu.raConnectionString = ConvertWCharNToUtf8Alloc(
      raConnectionStringW, cbRaConnectionStringW / sizeof(WCHAR), nullptr);
  if (!pdu.raConnectionString)
    return ERROR_INTERNAL_ERROR;
 
  WLog_INFO(TAG, "RaConnectionString: %s", pdu.raConnectionString);
  free(pdu.raConnectionString);
 
  if ((error = remdesk_send_ctl_result_pdu(context, 0)))
    WLog_ERR(TAG, "remdesk_send_ctl_result_pdu failed with error %" PRIu32 "!", error);
 
  return error;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_recv_ctl_authenticate_pdu(WINPR_ATTR_UNUSED RemdeskServerContext* context,
                                              wStream* s, const REMDESK_CHANNEL_HEADER* header)
{
  size_t cchTmpStringW = 0;
  const WCHAR* expertBlobW = nullptr;
  REMDESK_CTL_AUTHENTICATE_PDU pdu = WINPR_C_ARRAY_INIT;
 
  size_t cchRemaining = header->DataLength - 4ull;
  const size_t remaining = Stream_GetRemainingLength(s);
  if (cchRemaining > remaining)
    cchRemaining = remaining;
  cchRemaining /= sizeof(WCHAR);
 
  const WCHAR* pStringW = Stream_ConstPointer(s);
  const WCHAR* raConnectionStringW = pStringW;
 
  while ((cchTmpStringW < cchRemaining) && pStringW[cchTmpStringW])
    cchTmpStringW++;
 
  if ((cchTmpStringW >= cchRemaining) || !cchTmpStringW)
    return ERROR_INVALID_DATA;
 
  cchTmpStringW++;
  const size_t cbRaConnectionStringW = cchTmpStringW * sizeof(WCHAR);
  pStringW += cchTmpStringW;
  expertBlobW = pStringW;
  cchRemaining -= cchTmpStringW;
 
  size_t cchStringW = 0;
  while ((cchStringW < cchRemaining) && pStringW[cchStringW])
    cchStringW++;
 
  if ((cchStringW >= cchRemaining) || !cchStringW)
    return ERROR_INVALID_DATA;
 
  cchStringW++;
  const size_t cbExpertBlobW = cchStringW * sizeof(WCHAR);
  pdu.raConnectionString = ConvertWCharNToUtf8Alloc(
      raConnectionStringW, cbRaConnectionStringW / sizeof(WCHAR), nullptr);
  if (!pdu.raConnectionString)
    return ERROR_INTERNAL_ERROR;
 
  pdu.expertBlob = ConvertWCharNToUtf8Alloc(expertBlobW, cbExpertBlobW / sizeof(WCHAR), nullptr);
  if (!pdu.expertBlob)
  {
    free(pdu.raConnectionString);
    return ERROR_INTERNAL_ERROR;
  }
 
  WLog_INFO(TAG, "RaConnectionString: %s ExpertBlob: %s", pdu.raConnectionString, pdu.expertBlob);
  free(pdu.raConnectionString);
  free(pdu.expertBlob);
  return CHANNEL_RC_OK;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_recv_ctl_verify_password_pdu(RemdeskServerContext* context, wStream* s,
                                                 const REMDESK_CHANNEL_HEADER* header)
{
  REMDESK_CTL_VERIFY_PASSWORD_PDU pdu = WINPR_C_ARRAY_INIT;
 
  if (header->DataLength < 12ull)
  {
    WLog_ERR(TAG, "remdesk: HEADER::DataLength=%" PRIu32 ", but expected >= 12",
             header->DataLength);
    return ERROR_INVALID_DATA;
  }
 
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 8))
    return ERROR_INVALID_DATA;
 
  const WCHAR* expertBlobW = Stream_ConstPointer(s);
 
  size_t cbExpertBlobW = header->DataLength - 4;
  const size_t remaining = Stream_GetRemainingLength(s);
  if (cbExpertBlobW > remaining)
    cbExpertBlobW = remaining;
 
  pdu.expertBlob = ConvertWCharNToUtf8Alloc(expertBlobW, cbExpertBlobW / sizeof(WCHAR), nullptr);
  if (!pdu.expertBlob)
    return ERROR_INTERNAL_ERROR;
 
  WLog_INFO(TAG, "ExpertBlob: %s", pdu.expertBlob);
 
  // TODO: Callback?
 
  free(pdu.expertBlob);
  return remdesk_send_ctl_result_pdu(context, 0);
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_recv_ctl_pdu(RemdeskServerContext* context, wStream* s,
                                 const REMDESK_CHANNEL_HEADER* header)
{
  UINT error = CHANNEL_RC_OK;
  UINT32 msgType = 0;
 
  if (header->DataLength < 4)
  {
    WLog_ERR(TAG, "remdesk: HEADER::DataLength=%" PRIu32 ", but expected >= 4",
             header->DataLength);
    return ERROR_INVALID_DATA;
  }
 
  if (!Stream_CheckAndLogRequiredLength(TAG, s, header->DataLength))
    return ERROR_INVALID_DATA;
 
  Stream_Read_UINT32(s, msgType); /* msgType (4 bytes) */
  WLog_INFO(TAG, "msgType: %" PRIu32 "", msgType);
 
  switch (msgType)
  {
    case REMDESK_CTL_REMOTE_CONTROL_DESKTOP:
      if ((error = remdesk_recv_ctl_remote_control_desktop_pdu(context, s, header)))
      {
        WLog_ERR(TAG,
                 "remdesk_recv_ctl_remote_control_desktop_pdu failed with error %" PRIu32
                 "!",
                 error);
        return error;
      }
 
      break;
 
    case REMDESK_CTL_AUTHENTICATE:
      if ((error = remdesk_recv_ctl_authenticate_pdu(context, s, header)))
      {
        WLog_ERR(TAG, "remdesk_recv_ctl_authenticate_pdu failed with error %" PRIu32 "!",
                 error);
        return error;
      }
 
      break;
 
    case REMDESK_CTL_DISCONNECT:
      break;
 
    case REMDESK_CTL_VERSIONINFO:
      if ((error = remdesk_recv_ctl_version_info_pdu(context, s, header)))
      {
        WLog_ERR(TAG, "remdesk_recv_ctl_version_info_pdu failed with error %" PRIu32 "!",
                 error);
        return error;
      }
 
      break;
 
    case REMDESK_CTL_ISCONNECTED:
      break;
 
    case REMDESK_CTL_VERIFY_PASSWORD:
      if ((error = remdesk_recv_ctl_verify_password_pdu(context, s, header)))
      {
        WLog_ERR(TAG, "remdesk_recv_ctl_verify_password_pdu failed with error %" PRIu32 "!",
                 error);
        return error;
      }
 
      break;
 
    case REMDESK_CTL_EXPERT_ON_VISTA:
      break;
 
    case REMDESK_CTL_RANOVICE_NAME:
      break;
 
    case REMDESK_CTL_RAEXPERT_NAME:
      break;
 
    case REMDESK_CTL_TOKEN:
      break;
 
    default:
      WLog_ERR(TAG, "remdesk_recv_control_pdu: unknown msgType: %" PRIu32 "", msgType);
      error = ERROR_INVALID_DATA;
      break;
  }
 
  return error;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_server_receive_pdu(RemdeskServerContext* context, wStream* s)
{
  REMDESK_CHANNEL_HEADER header = WINPR_C_ARRAY_INIT;
 
  UINT error = remdesk_read_channel_header(s, &header);
  if (error)
  {
    WLog_ERR(TAG, "remdesk_read_channel_header failed with error %" PRIu32 "!", error);
    return error;
  }
 
  if (strcmp(header.ChannelName, "RC_CTL") == 0)
  {
    error = remdesk_recv_ctl_pdu(context, s, &header);
    if (error)
    {
      WLog_ERR(TAG, "remdesk_recv_ctl_pdu failed with error %" PRIu32 "!", error);
      return error;
    }
  }
  else if (strcmp(header.ChannelName, "70") == 0)
  {
  }
  else if (strcmp(header.ChannelName, "71") == 0)
  {
  }
  else if (strcmp(header.ChannelName, ".") == 0)
  {
  }
  else if (strcmp(header.ChannelName, "1000.") == 0)
  {
  }
  else if (strcmp(header.ChannelName, "RA_FX") == 0)
  {
  }
  else
  {
  }
 
  return error;
}
 
WINPR_ATTR_NODISCARD
static DWORD WINAPI remdesk_server_thread(LPVOID arg)
{
  void* buffer = nullptr;
  HANDLE events[8] = WINPR_C_ARRAY_INIT;
  HANDLE ChannelEvent = nullptr;
  DWORD BytesReturned = 0;
  UINT error = 0;
  RemdeskServerContext* context = (RemdeskServerContext*)arg;
  WINPR_ASSERT(context);
  wStream* s = Stream_New(nullptr, 4096);
 
  if (!s)
  {
    WLog_ERR(TAG, "Stream_New failed!");
    error = CHANNEL_RC_NO_MEMORY;
    goto out;
  }
 
  if (WTSVirtualChannelQuery(context->priv->ChannelHandle, WTSVirtualEventHandle, &buffer,
                             &BytesReturned) == TRUE)
  {
    if (BytesReturned == sizeof(HANDLE))
      ChannelEvent = *(HANDLE*)buffer;
 
    WTSFreeMemory(buffer);
  }
  else
  {
    WLog_ERR(TAG, "WTSVirtualChannelQuery failed!");
    error = ERROR_INTERNAL_ERROR;
    goto out;
  }
 
  {
    DWORD nCount = 0;
    events[nCount++] = ChannelEvent;
    events[nCount++] = context->priv->StopEvent;
 
    if ((error = remdesk_send_ctl_version_info_pdu(context)))
    {
      WLog_ERR(TAG, "remdesk_send_ctl_version_info_pdu failed with error %" PRIu32 "!",
               error);
      goto out;
    }
 
    while (1)
    {
      DWORD status = WaitForMultipleObjects(nCount, events, FALSE, INFINITE);
 
      if (status == WAIT_FAILED)
      {
        error = GetLastError();
        WLog_ERR(TAG, "WaitForMultipleObjects failed with error %" PRIu32 "", error);
        break;
      }
 
      status = WaitForSingleObject(context->priv->StopEvent, 0);
 
      if (status == WAIT_FAILED)
      {
        error = GetLastError();
        WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);
        break;
      }
 
      if (status == WAIT_OBJECT_0)
      {
        break;
      }
 
      const size_t len = Stream_Capacity(s);
      if (len > UINT32_MAX)
      {
        error = ERROR_INTERNAL_ERROR;
        break;
      }
      if (WTSVirtualChannelRead(context->priv->ChannelHandle, 0, Stream_BufferAs(s, char),
                                (UINT32)len, &BytesReturned))
      {
        if (BytesReturned)
          Stream_Seek(s, BytesReturned);
      }
      else
      {
        if (!Stream_EnsureRemainingCapacity(s, BytesReturned))
        {
          WLog_ERR(TAG, "Stream_EnsureRemainingCapacity failed!");
          error = CHANNEL_RC_NO_MEMORY;
          break;
        }
      }
 
      const size_t pos = Stream_GetPosition(s);
      if (pos >= 8)
      {
        Stream_ResetPosition(s);
        const UINT32 LengthLow = Stream_Get_UINT32(s);
        const UINT32 LengthHigh = Stream_Get_UINT32(s);
        if (!Stream_SetPosition(s, pos))
        {
          error = ERROR_INTERNAL_ERROR;
          break;
        }
        const UINT64 PduLength = LengthLow + LengthHigh + 8ull;
 
        if (PduLength >= pos)
        {
          Stream_SealLength(s);
          Stream_ResetPosition(s);
 
          error = remdesk_server_receive_pdu(context, s);
          if (error)
          {
            WLog_ERR(TAG, "remdesk_server_receive_pdu failed with error %" PRIu32 "!",
                     error);
            break;
          }
 
          Stream_ResetPosition(s);
        }
      }
    }
  }
out:
  Stream_Free(s, TRUE);
 
  if (error && context->rdpcontext)
    setChannelError(context->rdpcontext, error, "remdesk_server_thread reported an error");
 
  ExitThread(error);
  return error;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_server_start(RemdeskServerContext* context)
{
  context->priv->ChannelHandle =
      WTSVirtualChannelOpen(context->vcm, WTS_CURRENT_SESSION, REMDESK_SVC_CHANNEL_NAME);
 
  if (!context->priv->ChannelHandle)
  {
    WLog_ERR(TAG, "WTSVirtualChannelOpen failed!");
    return ERROR_INTERNAL_ERROR;
  }
 
  if (!(context->priv->StopEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr)))
  {
    WLog_ERR(TAG, "CreateEvent failed!");
    return ERROR_INTERNAL_ERROR;
  }
 
  if (!(context->priv->Thread =
            CreateThread(nullptr, 0, remdesk_server_thread, (void*)context, 0, nullptr)))
  {
    WLog_ERR(TAG, "CreateThread failed!");
    (void)CloseHandle(context->priv->StopEvent);
    context->priv->StopEvent = nullptr;
    return ERROR_INTERNAL_ERROR;
  }
 
  return CHANNEL_RC_OK;
}
 
WINPR_ATTR_NODISCARD
static UINT remdesk_server_stop(RemdeskServerContext* context)
{
  UINT error = 0;
  (void)SetEvent(context->priv->StopEvent);
 
  if (WaitForSingleObject(context->priv->Thread, INFINITE) == WAIT_FAILED)
  {
    error = GetLastError();
    WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "!", error);
    return error;
  }
 
  (void)CloseHandle(context->priv->Thread);
  (void)CloseHandle(context->priv->StopEvent);
  return CHANNEL_RC_OK;
}
 
RemdeskServerContext* remdesk_server_context_new(HANDLE vcm)
{
  RemdeskServerContext* context = nullptr;
  context = (RemdeskServerContext*)calloc(1, sizeof(RemdeskServerContext));
 
  if (context)
  {
    context->vcm = vcm;
    context->Start = remdesk_server_start;
    context->Stop = remdesk_server_stop;
    context->priv = (RemdeskServerPrivate*)calloc(1, sizeof(RemdeskServerPrivate));
 
    if (!context->priv)
    {
      free(context);
      return nullptr;
    }
 
    context->priv->Version = 1;
  }
 
  return context;
}
 
void remdesk_server_context_free(RemdeskServerContext* context)
{
  if (context)
  {
    if (context->priv->ChannelHandle != INVALID_HANDLE_VALUE)
      (void)WTSVirtualChannelClose(context->priv->ChannelHandle);
 
    free(context->priv);
    free(context);
  }
}