/src/FreeRDP/libfreerdp/core/transport.c

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/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Network Transport Layer
 *
 * Copyright 2011 Vic Lee
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <freerdp/config.h>

#include "settings.h"

#include <winpr/assert.h>

#include <winpr/crt.h>
#include <winpr/synch.h>
#include <winpr/print.h>
#include <winpr/stream.h>
#include <winpr/winsock.h>
#include <winpr/crypto.h>

#include <freerdp/log.h>
#include <freerdp/error.h>
#include <freerdp/utils/ringbuffer.h>

#include <openssl/bio.h>
#include <time.h>
#include <errno.h>
#include <fcntl.h>

#ifndef _WIN32
#include <netdb.h>
#include <sys/socket.h>
#endif /* _WIN32 */

#ifdef FREERDP_HAVE_VALGRIND_MEMCHECK_H
#include <valgrind/memcheck.h>
#endif

#include "tpkt.h"
#include "fastpath.h"
#include "transport.h"
#include "rdp.h"
#include "proxy.h"
#include "utils.h"
#include "state.h"
#include "childsession.h"
#include "settings.h"

#include "gateway/rdg.h"
#include "gateway/wst.h"
#include "gateway/arm.h"

#define TAG FREERDP_TAG("core.transport")

#define BUFFER_SIZE 16384

struct rdp_transport
{
  TRANSPORT_LAYER layer;
  BIO* frontBio;
  rdpRdg* rdg;
  rdpTsg* tsg;
  rdpWst* wst;
  rdpTls* tls;
  rdpContext* context;
  rdpNla* nla;
  void* ReceiveExtra;
  wStream* ReceiveBuffer;
  TransportRecv ReceiveCallback;
  wStreamPool* ReceivePool;
  HANDLE connectedEvent;
  BOOL NlaMode;
  BOOL RdstlsMode;
  BOOL AadMode;
  BOOL blocking;
  BOOL GatewayEnabled;
  CRITICAL_SECTION ReadLock;
  CRITICAL_SECTION WriteLock;
  ULONG written;
  HANDLE rereadEvent;
  BOOL haveMoreBytesToRead;
  wLog* log;
  rdpTransportIo io;
  HANDLE ioEvent;
  BOOL useIoEvent;
  BOOL earlyUserAuth;
};

static void transport_ssl_cb(SSL* ssl, int where, int ret)
{
  if (where & SSL_CB_ALERT)
  {
    rdpTransport* transport = (rdpTransport*)SSL_get_app_data(ssl);
    WINPR_ASSERT(transport);

    switch (ret)
    {
      case (SSL3_AL_FATAL << 8) | SSL_AD_ACCESS_DENIED:
      {
        if (!freerdp_get_last_error(transport_get_context(transport)))
        {
          WLog_Print(transport->log, WLOG_ERROR, "ACCESS DENIED");
          freerdp_set_last_error_log(transport_get_context(transport),
                                     FREERDP_ERROR_AUTHENTICATION_FAILED);
        }
      }
      break;

      case (SSL3_AL_FATAL << 8) | SSL_AD_INTERNAL_ERROR:
      {
        if (transport->NlaMode)
        {
          if (!freerdp_get_last_error(transport_get_context(transport)))
          {
            UINT32 kret = 0;
            if (transport->nla)
              kret = nla_get_error(transport->nla);
            if (kret == 0)
              kret = FREERDP_ERROR_CONNECT_PASSWORD_CERTAINLY_EXPIRED;
            freerdp_set_last_error_log(transport_get_context(transport), kret);
          }
        }

        break;

        case (SSL3_AL_WARNING << 8) | SSL3_AD_CLOSE_NOTIFY:
          break;

        default:
          WLog_Print(transport->log, WLOG_WARN,
                     "Unhandled SSL error (where=%d, ret=%d [%s, %s])", where, ret,
                     SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret));
          break;
      }
    }
  }
}

wStream* transport_send_stream_init(rdpTransport* transport, size_t size)
{
  wStream* s;
  WINPR_ASSERT(transport);

  if (!(s = StreamPool_Take(transport->ReceivePool, size)))
    return NULL;

  if (!Stream_EnsureCapacity(s, size))
  {
    Stream_Release(s);
    return NULL;
  }

  Stream_SetPosition(s, 0);
  return s;
}

BOOL transport_attach(rdpTransport* transport, int sockfd)
{
  if (!transport)
    return FALSE;
  return IFCALLRESULT(FALSE, transport->io.TransportAttach, transport, sockfd);
}

static BOOL transport_default_attach(rdpTransport* transport, int sockfd)
{
  BIO* socketBio = NULL;
  BIO* bufferedBio;
  const rdpSettings* settings;
  rdpContext* context = transport_get_context(transport);

  if (sockfd < 0)
  {
    WLog_WARN(TAG, "Running peer without socket (sockfd=%d)", sockfd);
    return TRUE;
  }

  settings = context->settings;
  WINPR_ASSERT(settings);

  if (sockfd >= 0)
  {
    if (!freerdp_tcp_set_keep_alive_mode(settings, sockfd))
      goto fail;

    socketBio = BIO_new(BIO_s_simple_socket());

    if (!socketBio)
      goto fail;

    BIO_set_fd(socketBio, sockfd, BIO_CLOSE);
  }

  bufferedBio = BIO_new(BIO_s_buffered_socket());
  if (!bufferedBio)
    goto fail;

  if (socketBio)
    bufferedBio = BIO_push(bufferedBio, socketBio);
  WINPR_ASSERT(bufferedBio);
  transport->frontBio = bufferedBio;
  return TRUE;
fail:

  if (socketBio)
    BIO_free_all(socketBio);
  else
    closesocket(sockfd);

  return FALSE;
}

BOOL transport_connect_rdp(rdpTransport* transport)
{
  if (!transport)
    return FALSE;

  switch (utils_authenticate(transport_get_context(transport)->instance, AUTH_RDP, FALSE))
  {
    case AUTH_SKIP:
    case AUTH_SUCCESS:
    case AUTH_NO_CREDENTIALS:
      return TRUE;
    case AUTH_CANCELLED:
      freerdp_set_last_error_if_not(transport_get_context(transport),
                                    FREERDP_ERROR_CONNECT_CANCELLED);
      return FALSE;
    default:
      return FALSE;
  }
}

BOOL transport_connect_tls(rdpTransport* transport)
{
  const rdpSettings* settings;
  rdpContext* context = transport_get_context(transport);

  settings = context->settings;
  WINPR_ASSERT(settings);

  /* Only prompt for password if we use TLS (NLA also calls this function) */
  if (settings->SelectedProtocol == PROTOCOL_SSL)
  {
    switch (utils_authenticate(context->instance, AUTH_TLS, FALSE))
    {
      case AUTH_SKIP:
      case AUTH_SUCCESS:
      case AUTH_NO_CREDENTIALS:
        break;
      case AUTH_CANCELLED:
        freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_CANCELLED);
        return FALSE;
      default:
        return FALSE;
    }
  }

  return IFCALLRESULT(FALSE, transport->io.TLSConnect, transport);
}

static BOOL transport_default_connect_tls(rdpTransport* transport)
{
  int tlsStatus;
  rdpTls* tls = NULL;
  rdpContext* context;
  rdpSettings* settings;

  WINPR_ASSERT(transport);

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  settings = context->settings;
  WINPR_ASSERT(settings);

  if (!(tls = freerdp_tls_new(settings)))
    return FALSE;

  transport->tls = tls;

  if (transport->GatewayEnabled)
    transport->layer = TRANSPORT_LAYER_TSG_TLS;
  else
    transport->layer = TRANSPORT_LAYER_TLS;

  tls->hostname = settings->ServerHostname;
  tls->serverName = settings->UserSpecifiedServerName;
  tls->port = settings->ServerPort;

  if (tls->port == 0)
    tls->port = 3389;

  tls->isGatewayTransport = FALSE;
  tlsStatus = freerdp_tls_connect(tls, transport->frontBio);

  if (tlsStatus < 1)
  {
    if (tlsStatus < 0)
    {
      freerdp_set_last_error_if_not(context, FREERDP_ERROR_TLS_CONNECT_FAILED);
    }
    else
    {
      freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_CANCELLED);
    }

    return FALSE;
  }

  transport->frontBio = tls->bio;
  BIO_callback_ctrl(tls->bio, BIO_CTRL_SET_CALLBACK, (bio_info_cb*)(void*)transport_ssl_cb);
  SSL_set_app_data(tls->ssl, transport);

  if (!transport->frontBio)
  {
    WLog_Print(transport->log, WLOG_ERROR, "unable to prepend a filtering TLS bio");
    return FALSE;
  }

  return TRUE;
}

BOOL transport_connect_nla(rdpTransport* transport, BOOL earlyUserAuth)
{
  rdpContext* context = NULL;
  rdpSettings* settings = NULL;
  rdpRdp* rdp = NULL;
  if (!transport)
    return FALSE;

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  settings = context->settings;
  WINPR_ASSERT(settings);

  rdp = context->rdp;
  WINPR_ASSERT(rdp);

  if (!transport_connect_tls(transport))
    return FALSE;

  if (!settings->Authentication)
    return TRUE;

  nla_free(rdp->nla);
  rdp->nla = nla_new(context, transport);

  if (!rdp->nla)
    return FALSE;

  nla_set_early_user_auth(rdp->nla, earlyUserAuth);

  transport_set_nla_mode(transport, TRUE);

  if (settings->AuthenticationServiceClass)
  {
    if (!nla_set_service_principal(rdp->nla, settings->AuthenticationServiceClass,
                                   freerdp_settings_get_server_name(settings)))
      return FALSE;
  }

  if (nla_client_begin(rdp->nla) < 0)
  {
    WLog_Print(transport->log, WLOG_ERROR, "NLA begin failed");

    freerdp_set_last_error_if_not(context, FREERDP_ERROR_AUTHENTICATION_FAILED);

    transport_set_nla_mode(transport, FALSE);
    return FALSE;
  }

  return rdp_client_transition_to_state(rdp, CONNECTION_STATE_NLA);
}

BOOL transport_connect_rdstls(rdpTransport* transport)
{
  BOOL rc = FALSE;
  rdpRdstls* rdstls = NULL;
  rdpContext* context = NULL;

  WINPR_ASSERT(transport);

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  if (!transport_connect_tls(transport))
    goto fail;

  rdstls = rdstls_new(context, transport);
  if (!rdstls)
    goto fail;

  transport_set_rdstls_mode(transport, TRUE);

  if (rdstls_authenticate(rdstls) < 0)
  {
    WLog_Print(transport->log, WLOG_ERROR, "RDSTLS authentication failed");
    freerdp_set_last_error_if_not(context, FREERDP_ERROR_AUTHENTICATION_FAILED);
    goto fail;
  }

  transport_set_rdstls_mode(transport, FALSE);
  rc = TRUE;
fail:
  rdstls_free(rdstls);
  return rc;
}

BOOL transport_connect_aad(rdpTransport* transport)
{
  rdpContext* context = NULL;
  rdpSettings* settings = NULL;
  rdpRdp* rdp = NULL;
  if (!transport)
    return FALSE;

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  settings = context->settings;
  WINPR_ASSERT(settings);

  rdp = context->rdp;
  WINPR_ASSERT(rdp);

  if (!transport_connect_tls(transport))
    return FALSE;

  if (!settings->Authentication)
    return TRUE;

  if (!rdp->aad)
    return FALSE;

  transport_set_aad_mode(transport, TRUE);

  if (aad_client_begin(rdp->aad) < 0)
  {
    WLog_Print(transport->log, WLOG_ERROR, "AAD begin failed");

    freerdp_set_last_error_if_not(context, FREERDP_ERROR_AUTHENTICATION_FAILED);

    transport_set_aad_mode(transport, FALSE);
    return FALSE;
  }

  return rdp_client_transition_to_state(rdp, CONNECTION_STATE_AAD);
}

BOOL transport_connect(rdpTransport* transport, const char* hostname, UINT16 port, DWORD timeout)
{
  int sockfd;
  BOOL status = FALSE;
  rdpSettings* settings;
  rdpContext* context = transport_get_context(transport);
  BOOL rpcFallback;

  WINPR_ASSERT(context);
  WINPR_ASSERT(hostname);

  settings = context->settings;
  WINPR_ASSERT(settings);

  rpcFallback = !settings->GatewayHttpTransport;

  if (transport->GatewayEnabled)
  {
    if (settings->GatewayUrl)
    {
      WINPR_ASSERT(!transport->wst);
      transport->wst = wst_new(context);

      if (!transport->wst)
        return FALSE;

      status = wst_connect(transport->wst, timeout);

      if (status)
      {
        transport->frontBio = wst_get_front_bio_and_take_ownership(transport->wst);
        WINPR_ASSERT(transport->frontBio);
        BIO_set_nonblock(transport->frontBio, 0);
        transport->layer = TRANSPORT_LAYER_TSG;
        status = TRUE;
      }
      else
      {
        wst_free(transport->wst);
        transport->wst = NULL;
      }
    }
    if (!status && settings->GatewayHttpTransport)
    {
      WINPR_ASSERT(!transport->rdg);
      transport->rdg = rdg_new(context);

      if (!transport->rdg)
        return FALSE;

      status = rdg_connect(transport->rdg, timeout, &rpcFallback);

      if (status)
      {
        transport->frontBio = rdg_get_front_bio_and_take_ownership(transport->rdg);
        WINPR_ASSERT(transport->frontBio);
        BIO_set_nonblock(transport->frontBio, 0);
        transport->layer = TRANSPORT_LAYER_TSG;
        status = TRUE;
      }
      else
      {
        rdg_free(transport->rdg);
        transport->rdg = NULL;
      }
    }

    if (!status && settings->GatewayRpcTransport && rpcFallback)
    {
      WINPR_ASSERT(!transport->tsg);
      transport->tsg = tsg_new(transport);

      if (!transport->tsg)
        return FALSE;

      /* Reset error condition from RDG */
      freerdp_set_last_error_log(context, FREERDP_ERROR_SUCCESS);
      status = tsg_connect(transport->tsg, hostname, port, timeout);

      if (status)
      {
        transport->frontBio = tsg_get_bio(transport->tsg);
        transport->layer = TRANSPORT_LAYER_TSG;
        status = TRUE;
      }
      else
      {
        tsg_free(transport->tsg);
        transport->tsg = NULL;
      }
    }
  }
  else
  {
    UINT16 peerPort;
    const char *proxyHostname, *proxyUsername, *proxyPassword;
    BOOL isProxyConnection =
        proxy_prepare(settings, &proxyHostname, &peerPort, &proxyUsername, &proxyPassword);

    if (isProxyConnection)
      sockfd = transport_tcp_connect(transport, proxyHostname, peerPort, timeout);
    else
      sockfd = transport_tcp_connect(transport, hostname, port, timeout);

    if (sockfd < 0)
      return FALSE;

    if (!transport_attach(transport, sockfd))
      return FALSE;

    if (isProxyConnection)
    {
      if (!proxy_connect(settings, transport->frontBio, proxyUsername, proxyPassword,
                         hostname, port))
        return FALSE;
    }

    status = TRUE;
  }

  return status;
}

BOOL transport_connect_childsession(rdpTransport* transport)
{
  WINPR_ASSERT(transport);

  transport->frontBio = createChildSessionBio();
  if (!transport->frontBio)
    return FALSE;

  transport->layer = TRANSPORT_LAYER_TSG;
  return TRUE;
}

BOOL transport_accept_rdp(rdpTransport* transport)
{
  if (!transport)
    return FALSE;
  /* RDP encryption */
  return TRUE;
}

BOOL transport_accept_tls(rdpTransport* transport)
{
  if (!transport)
    return FALSE;
  return IFCALLRESULT(FALSE, transport->io.TLSAccept, transport);
}

static BOOL transport_default_accept_tls(rdpTransport* transport)
{
  rdpContext* context = transport_get_context(transport);
  rdpSettings* settings;

  WINPR_ASSERT(context);

  settings = context->settings;
  WINPR_ASSERT(settings);

  if (!transport->tls)
    transport->tls = freerdp_tls_new(settings);

  transport->layer = TRANSPORT_LAYER_TLS;

  if (!freerdp_tls_accept(transport->tls, transport->frontBio, settings))
    return FALSE;

  transport->frontBio = transport->tls->bio;
  return TRUE;
}

BOOL transport_accept_nla(rdpTransport* transport)
{
  rdpContext* context = transport_get_context(transport);
  rdpSettings* settings;

  WINPR_ASSERT(context);

  settings = context->settings;
  WINPR_ASSERT(settings);

  if (!IFCALLRESULT(FALSE, transport->io.TLSAccept, transport))
    return FALSE;

  /* Network Level Authentication */

  if (!settings->Authentication)
    return TRUE;

  if (!transport->nla)
  {
    transport->nla = nla_new(context, transport);
    transport_set_nla_mode(transport, TRUE);
  }

  if (nla_authenticate(transport->nla) < 0)
  {
    WLog_Print(transport->log, WLOG_ERROR, "client authentication failure");
    transport_set_nla_mode(transport, FALSE);
    nla_free(transport->nla);
    transport->nla = NULL;
    freerdp_tls_set_alert_code(transport->tls, TLS_ALERT_LEVEL_FATAL,
                               TLS_ALERT_DESCRIPTION_ACCESS_DENIED);
    freerdp_tls_send_alert(transport->tls);
    return FALSE;
  }

  /* don't free nla module yet, we need to copy the credentials from it first */
  transport_set_nla_mode(transport, FALSE);
  return TRUE;
}

BOOL transport_accept_rdstls(rdpTransport* transport)
{
  BOOL rc = FALSE;
  rdpRdstls* rdstls = NULL;
  rdpContext* context = NULL;

  WINPR_ASSERT(transport);

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  if (!IFCALLRESULT(FALSE, transport->io.TLSAccept, transport))
    goto fail;

  rdstls = rdstls_new(context, transport);
  if (!rdstls)
    goto fail;

  transport_set_rdstls_mode(transport, TRUE);

  if (rdstls_authenticate(rdstls) < 0)
  {
    WLog_Print(transport->log, WLOG_ERROR, "client authentication failure");
    freerdp_tls_set_alert_code(transport->tls, TLS_ALERT_LEVEL_FATAL,
                               TLS_ALERT_DESCRIPTION_ACCESS_DENIED);
    freerdp_tls_send_alert(transport->tls);
    goto fail;
  }

  transport_set_rdstls_mode(transport, FALSE);
  rc = TRUE;
fail:
  rdstls_free(rdstls);
  return rc;
}

#define WLog_ERR_BIO(transport, biofunc, bio) \
  transport_bio_error_log(transport, biofunc, bio, __FILE__, __func__, __LINE__)

static void transport_bio_error_log(rdpTransport* transport, LPCSTR biofunc, BIO* bio, LPCSTR file,
                                    LPCSTR func, DWORD line)
{
  unsigned long sslerr;
  int saveerrno;
  DWORD level;

  WINPR_ASSERT(transport);

  saveerrno = errno;
  level = WLOG_ERROR;

  if (level < WLog_GetLogLevel(transport->log))
    return;

  if (ERR_peek_error() == 0)
  {
    const char* fmt = "%s returned a system error %d: %s";
    if (saveerrno == 0)
      fmt = "%s retries exceeded";
    WLog_PrintMessage(transport->log, WLOG_MESSAGE_TEXT, level, line, file, func, fmt, biofunc,
                      saveerrno, strerror(saveerrno));
    return;
  }

  while ((sslerr = ERR_get_error()))
  {
    char buf[120] = { 0 };
    const char* fmt = "%s returned an error: %s";

    ERR_error_string_n(sslerr, buf, 120);
    WLog_PrintMessage(transport->log, WLOG_MESSAGE_TEXT, level, line, file, func, fmt, biofunc,
                      buf);
  }
}

static SSIZE_T transport_read_layer(rdpTransport* transport, BYTE* data, size_t bytes)
{
  SSIZE_T read = 0;
  rdpRdp* rdp;
  rdpContext* context;

  WINPR_ASSERT(transport);

  context = transport_get_context(transport);
  WINPR_ASSERT(context);

  rdp = context->rdp;
  WINPR_ASSERT(rdp);

  if (!transport->frontBio || (bytes > SSIZE_MAX))
  {
    transport->layer = TRANSPORT_LAYER_CLOSED;
    freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED);
    return -1;
  }

  while (read < (SSIZE_T)bytes)
  {
    const SSIZE_T tr = (SSIZE_T)bytes - read;
    int r = (int)((tr > INT_MAX) ? INT_MAX : tr);
    ERR_clear_error();
    int status = BIO_read(transport->frontBio, data + read, r);

    if (freerdp_shall_disconnect_context(context))
      return -1;

    if (status <= 0)
    {
      if (!transport->frontBio || !BIO_should_retry(transport->frontBio))
      {
        /* something unexpected happened, let's close */
        if (!transport->frontBio)
        {
          WLog_Print(transport->log, WLOG_ERROR, "BIO_read: transport->frontBio null");
          return -1;
        }

        WLog_ERR_BIO(transport, "BIO_read", transport->frontBio);
        transport->layer = TRANSPORT_LAYER_CLOSED;
        freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED);
        return -1;
      }

      /* non blocking will survive a partial read */
      if (!transport->blocking)
        return read;

      /* blocking means that we can't continue until we have read the number of requested
       * bytes */
      if (BIO_wait_read(transport->frontBio, 100) < 0)
      {
        WLog_ERR_BIO(transport, "BIO_wait_read", transport->frontBio);
        return -1;
      }

      continue;
    }

#ifdef FREERDP_HAVE_VALGRIND_MEMCHECK_H
    VALGRIND_MAKE_MEM_DEFINED(data + read, bytes - read);
#endif
    read += status;
    rdp->inBytes += status;
  }

  return read;
}

/**
 * @brief Tries to read toRead bytes from the specified transport
 *
 * Try to read toRead bytes from the transport to the stream.
 * In case it was not possible to read toRead bytes 0 is returned. The stream is always advanced by
 * the number of bytes read.
 *
 * The function assumes that the stream has enough capacity to hold the data.
 *
 * @param[in] transport rdpTransport
 * @param[in] s wStream
 * @param[in] toRead number of bytes to read
 * @return < 0 on error; 0 if not enough data is available (non blocking mode); 1 toRead bytes read
 */
static SSIZE_T transport_read_layer_bytes(rdpTransport* transport, wStream* s, size_t toRead)
{
  SSIZE_T status;
  if (!transport)
    return -1;

  if (toRead > SSIZE_MAX)
    return 0;

  status = IFCALLRESULT(-1, transport->io.ReadBytes, transport, Stream_Pointer(s), toRead);

  if (status <= 0)
    return status;

  Stream_Seek(s, (size_t)status);
  return status == (SSIZE_T)toRead ? 1 : 0;
}

/**
 * @brief Try to read a complete PDU (NLA, fast-path or tpkt) from the underlying transport.
 *
 * If possible a complete PDU is read, in case of non blocking transport this might not succeed.
 * Except in case of an error the passed stream will point to the last byte read (correct
 * position). When the pdu read is completed the stream is sealed and the pointer set to 0
 *
 * @param[in] transport rdpTransport
 * @param[in] s wStream
 * @return < 0 on error; 0 if not enough data is available (non blocking mode); > 0 number of
 * bytes of the *complete* pdu read
 */
int transport_read_pdu(rdpTransport* transport, wStream* s)
{
  if (!transport)
    return -1;
  return IFCALLRESULT(-1, transport->io.ReadPdu, transport, s);
}

static SSIZE_T parse_nla_mode_pdu(rdpTransport* transport, wStream* stream)
{
  SSIZE_T pduLength = 0;
  wStream sbuffer = { 0 };
  wStream* s = Stream_StaticConstInit(&sbuffer, Stream_Buffer(stream), Stream_Length(stream));
  /*
   * In case NlaMode is set TSRequest package(s) are expected
   * 0x30 = DER encoded data with these bits set:
   * bit 6 P/C constructed
   * bit 5 tag number - sequence
   */
  UINT8 typeEncoding;
  if (Stream_GetRemainingLength(s) < 1)
    return 0;
  Stream_Read_UINT8(s, typeEncoding);
  if (typeEncoding == 0x30)
  {
    /* TSRequest (NLA) */
    UINT8 lengthEncoding;
    if (Stream_GetRemainingLength(s) < 1)
      return 0;
    Stream_Read_UINT8(s, lengthEncoding);
    if (lengthEncoding & 0x80)
    {
      if ((lengthEncoding & ~(0x80)) == 1)
      {
        UINT8 length;
        if (Stream_GetRemainingLength(s) < 1)
          return 0;
        Stream_Read_UINT8(s, length);
        pduLength = length;
        pduLength += 3;
      }
      else if ((lengthEncoding & ~(0x80)) == 2)
      {
        /* check for header bytes already was readed in previous calls */
        UINT16 length;
        if (Stream_GetRemainingLength(s) < 2)
          return 0;
        Stream_Read_UINT16_BE(s, length);
        pduLength = length;
        pduLength += 4;
      }
      else
      {
        WLog_Print(transport->log, WLOG_ERROR, "Error reading TSRequest!");
        return -1;
      }
    }
    else
    {
      pduLength = lengthEncoding;
      pduLength += 2;
    }
  }

  return pduLength;
}

static SSIZE_T parse_default_mode_pdu(rdpTransport* transport, wStream* stream)
{
  SSIZE_T pduLength = 0;
  wStream sbuffer = { 0 };
  wStream* s = Stream_StaticConstInit(&sbuffer, Stream_Buffer(stream), Stream_Length(stream));

  UINT8 version;
  if (Stream_GetRemainingLength(s) < 1)
    return 0;
  Stream_Read_UINT8(s, version);
  if (version == 0x03)
  {
    /* TPKT header */
    UINT16 length;
    if (Stream_GetRemainingLength(s) < 3)
      return 0;
    Stream_Seek(s, 1);
    Stream_Read_UINT16_BE(s, length);
    pduLength = length;

    /* min and max values according to ITU-T Rec. T.123 (01/2007) section 8 */
    if ((pduLength < 7) || (pduLength > 0xFFFF))
    {
      WLog_Print(transport->log, WLOG_ERROR, "tpkt - invalid pduLength: %" PRIdz, pduLength);
      return -1;
    }
  }
  else
  {
    /* Fast-Path Header */
    UINT8 length1;
    if (Stream_GetRemainingLength(s) < 1)
      return 0;
    Stream_Read_UINT8(s, length1);
    if (length1 & 0x80)
    {
      UINT8 length2;
      if (Stream_GetRemainingLength(s) < 1)
        return 0;
      Stream_Read_UINT8(s, length2);
      pduLength = ((length1 & 0x7F) << 8) | length2;
    }
    else
      pduLength = length1;

    /*
     * fast-path has 7 bits for length so the maximum size, including headers is 0x8000
     * The theoretical minimum fast-path PDU consists only of two header bytes plus one
     * byte for data (e.g. fast-path input synchronize pdu)
     */
    if (pduLength < 3 || pduLength > 0x8000)
    {
      WLog_Print(transport->log, WLOG_ERROR, "fast path - invalid pduLength: %" PRIdz,
                 pduLength);
      return -1;
    }
  }

  return pduLength;
}

SSIZE_T transport_parse_pdu(rdpTransport* transport, wStream* s, BOOL* incomplete)
{
  size_t pduLength = 0;

  if (!transport)
    return -1;

  if (!s)
    return -1;

  if (incomplete)
    *incomplete = TRUE;

  Stream_SealLength(s);
  if (transport->NlaMode)
    pduLength = parse_nla_mode_pdu(transport, s);
  else if (transport->RdstlsMode)
    pduLength = rdstls_parse_pdu(transport->log, s);
  else
    pduLength = parse_default_mode_pdu(transport, s);

  if (pduLength == 0)
    return pduLength;

  const size_t len = Stream_Length(s);
  if (len > pduLength)
    return -1;

  if (incomplete)
    *incomplete = len < pduLength;

  return pduLength;
}

static int transport_default_read_pdu(rdpTransport* transport, wStream* s)
{
  BOOL incomplete;
  SSIZE_T status;
  size_t pduLength;
  size_t position;

  WINPR_ASSERT(transport);
  WINPR_ASSERT(s);

  /* RDS AAD Auth PDUs have no length indicator. We need to determine the end of the PDU by
   * reading in one byte at a time until we encounter the terminating null byte */
  if (transport->AadMode)
  {
    BYTE c = '\0';
    do
    {
      const int rc = transport_read_layer(transport, &c, 1);
      if (rc != 1)
        return rc;
      if (!Stream_EnsureRemainingCapacity(s, 1))
        return -1;
      Stream_Write_UINT8(s, c);
    } while (c != '\0');
  }
  else if (transport->earlyUserAuth)
  {
    if (!Stream_EnsureCapacity(s, 4))
      return -1;
    const int rc = transport_read_layer_bytes(transport, s, 4);
    if (rc != 1)
      return rc;
  }
  else
  {
    /* Read in pdu length */
    status = transport_parse_pdu(transport, s, &incomplete);
    while ((status == 0) && incomplete)
    {
      int rc;
      if (!Stream_EnsureRemainingCapacity(s, 1))
        return -1;
      rc = transport_read_layer_bytes(transport, s, 1);
      if (rc != 1)
        return rc;
      status = transport_parse_pdu(transport, s, &incomplete);
    }

    if (status < 0)
      return -1;

    pduLength = (size_t)status;

    /* Read in rest of the PDU */
    if (!Stream_EnsureCapacity(s, pduLength))
      return -1;

    position = Stream_GetPosition(s);
    if (position > pduLength)
      return -1;

    status = transport_read_layer_bytes(transport, s, pduLength - Stream_GetPosition(s));

    if (status != 1)
      return status;

    if (Stream_GetPosition(s) >= pduLength)
      WLog_Packet(transport->log, WLOG_TRACE, Stream_Buffer(s), pduLength,
                  WLOG_PACKET_INBOUND);
  }

  Stream_SealLength(s);
  Stream_SetPosition(s, 0);
  return Stream_Length(s);
}

int transport_write(rdpTransport* transport, wStream* s)
{
  if (!transport)
    return -1;

  return IFCALLRESULT(-1, transport->io.WritePdu, transport, s);
}

static int transport_default_write(rdpTransport* transport, wStream* s)
{
  size_t length;
  int status = -1;
  int writtenlength = 0;
  rdpRdp* rdp;
  rdpContext* context = transport_get_context(transport);

  WINPR_ASSERT(transport);
  WINPR_ASSERT(context);

  if (!s)
    return -1;

  Stream_AddRef(s);

  rdp = context->rdp;
  if (!rdp)
    goto fail;

  EnterCriticalSection(&(transport->WriteLock));
  if (!transport->frontBio)
    goto out_cleanup;

  length = Stream_GetPosition(s);
  writtenlength = length;
  Stream_SetPosition(s, 0);

  if (length > 0)
  {
    rdp->outBytes += length;
    WLog_Packet(transport->log, WLOG_TRACE, Stream_Buffer(s), length, WLOG_PACKET_OUTBOUND);
  }

  while (length > 0)
  {
    ERR_clear_error();
    status = BIO_write(transport->frontBio, Stream_ConstPointer(s), length);

    if (status <= 0)
    {
      /* the buffered BIO that is at the end of the chain always says OK for writing,
       * so a retry means that for any reason we need to read. The most probable
       * is a SSL or TSG BIO in the chain.
       */
      if (!BIO_should_retry(transport->frontBio))
      {
        WLog_ERR_BIO(transport, "BIO_should_retry", transport->frontBio);
        goto out_cleanup;
      }

      /* non-blocking can live with blocked IOs */
      if (!transport->blocking)
      {
        WLog_ERR_BIO(transport, "BIO_write", transport->frontBio);
        goto out_cleanup;
      }

      if (BIO_wait_write(transport->frontBio, 100) < 0)
      {
        WLog_ERR_BIO(transport, "BIO_wait_write", transport->frontBio);
        status = -1;
        goto out_cleanup;
      }

      continue;
    }

    WINPR_ASSERT(context->settings);
    if (transport->blocking || context->settings->WaitForOutputBufferFlush)
    {
      while (BIO_write_blocked(transport->frontBio))
      {
        if (BIO_wait_write(transport->frontBio, 100) < 0)
        {
          WLog_Print(transport->log, WLOG_ERROR, "error when selecting for write");
          status = -1;
          goto out_cleanup;
        }

        if (BIO_flush(transport->frontBio) < 1)
        {
          WLog_Print(transport->log, WLOG_ERROR, "error when flushing outputBuffer");
          status = -1;
          goto out_cleanup;
        }
      }
    }

    length -= status;
    Stream_Seek(s, status);
  }

  transport->written += writtenlength;
out_cleanup:

  if (status < 0)
  {
    /* A write error indicates that the peer has dropped the connection */
    transport->layer = TRANSPORT_LAYER_CLOSED;
    freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED);
  }

  LeaveCriticalSection(&(transport->WriteLock));
fail:
  Stream_Release(s);
  return status;
}

DWORD transport_get_event_handles(rdpTransport* transport, HANDLE* events, DWORD count)
{
  DWORD nCount = 0; /* always the reread Event */

  WINPR_ASSERT(transport);
  WINPR_ASSERT(events);
  WINPR_ASSERT(count > 0);

  if (events)
  {
    if (count < 1)
    {
      WLog_Print(transport->log, WLOG_ERROR, "provided handles array is too small");
      return 0;
    }

    events[nCount++] = transport->rereadEvent;

    if (transport->useIoEvent)
    {
      if (count < 2)
        return 0;
      events[nCount++] = transport->ioEvent;
    }
  }

  if (!transport->GatewayEnabled)
  {
    if (events)
    {
      if (nCount >= count)
      {
        WLog_Print(transport->log, WLOG_ERROR,
                   "provided handles array is too small (count=%" PRIu32 " nCount=%" PRIu32
                   ")",
                   count, nCount);
        return 0;
      }

      if (transport->frontBio)
      {
        if (BIO_get_event(transport->frontBio, &events[nCount]) != 1)
        {
          WLog_Print(transport->log, WLOG_ERROR, "error getting the frontBio handle");
          return 0;
        }
        nCount++;
      }
    }
  }
  else
  {
    if (transport->rdg)
    {
      const DWORD tmp =
          rdg_get_event_handles(transport->rdg, &events[nCount], count - nCount);

      if (tmp == 0)
        return 0;

      nCount += tmp;
    }
    else if (transport->tsg)
    {
      const DWORD tmp =
          tsg_get_event_handles(transport->tsg, &events[nCount], count - nCount);

      if (tmp == 0)
        return 0;

      nCount += tmp;
    }
    else if (transport->wst)
    {
      const DWORD tmp =
          wst_get_event_handles(transport->wst, &events[nCount], count - nCount);

      if (tmp == 0)
        return 0;

      nCount += tmp;
    }
  }

  return nCount;
}

#if defined(WITH_FREERDP_DEPRECATED)
void transport_get_fds(rdpTransport* transport, void** rfds, int* rcount)
{
  DWORD index;
  DWORD nCount;
  HANDLE events[MAXIMUM_WAIT_OBJECTS] = { 0 };

  WINPR_ASSERT(transport);
  WINPR_ASSERT(rfds);
  WINPR_ASSERT(rcount);

  nCount = transport_get_event_handles(transport, events, ARRAYSIZE(events));
  *rcount = nCount + 1;

  for (index = 0; index < nCount; index++)
  {
    rfds[index] = GetEventWaitObject(events[index]);
  }

  rfds[nCount] = GetEventWaitObject(transport->rereadEvent);
}
#endif

BOOL transport_is_write_blocked(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  WINPR_ASSERT(transport->frontBio);
  return BIO_write_blocked(transport->frontBio);
}

int transport_drain_output_buffer(rdpTransport* transport)
{
  BOOL status = FALSE;

  WINPR_ASSERT(transport);
  WINPR_ASSERT(transport->frontBio);
  if (BIO_write_blocked(transport->frontBio))
  {
    if (BIO_flush(transport->frontBio) < 1)
      return -1;

    status |= BIO_write_blocked(transport->frontBio);
  }

  return status;
}

int transport_check_fds(rdpTransport* transport)
{
  int status;
  state_run_t recv_status;
  wStream* received;
  rdpContext* context = transport_get_context(transport);

  WINPR_ASSERT(context);

  if (transport->layer == TRANSPORT_LAYER_CLOSED)
  {
    WLog_Print(transport->log, WLOG_DEBUG, "transport_check_fds: transport layer closed");
    freerdp_set_last_error_if_not(context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED);
    return -1;
  }

  /**
   * Note: transport_read_pdu tries to read one PDU from
   * the transport layer.
   * The ReceiveBuffer might have a position > 0 in case of a non blocking
   * transport. If transport_read_pdu returns 0 the pdu couldn't be read at
   * this point.
   * Note that transport->ReceiveBuffer is replaced after each iteration
   * of this loop with a fresh stream instance from a pool.
   */
  if ((status = transport_read_pdu(transport, transport->ReceiveBuffer)) <= 0)
  {
    if (status < 0)
      WLog_Print(transport->log, WLOG_DEBUG, "transport_check_fds: transport_read_pdu() - %i",
                 status);
    if (transport->haveMoreBytesToRead)
    {
      transport->haveMoreBytesToRead = FALSE;
      ResetEvent(transport->rereadEvent);
    }
    return status;
  }

  received = transport->ReceiveBuffer;

  if (!(transport->ReceiveBuffer = StreamPool_Take(transport->ReceivePool, 0)))
    return -1;

  /**
   * status:
   *  -1: error
   *   0: success
   *   1: redirection
   */
  WINPR_ASSERT(transport->ReceiveCallback);
  recv_status = transport->ReceiveCallback(transport, received, transport->ReceiveExtra);
  Stream_Release(received);

  if (state_run_failed(recv_status))
  {
    char buffer[64] = { 0 };
    WLog_Print(transport->log, WLOG_ERROR,
               "transport_check_fds: transport->ReceiveCallback() - %s",
               state_run_result_string(recv_status, buffer, ARRAYSIZE(buffer)));
    return -1;
  }

  /* Run this again to be sure we consumed all input data.
   * This will be repeated until a (not fully) received packet is in buffer
   */
  if (!transport->haveMoreBytesToRead)
  {
    transport->haveMoreBytesToRead = TRUE;
    SetEvent(transport->rereadEvent);
  }
  return recv_status;
}

BOOL transport_set_blocking_mode(rdpTransport* transport, BOOL blocking)
{
  WINPR_ASSERT(transport);

  transport->blocking = blocking;

  if (transport->frontBio)
  {
    if (!BIO_set_nonblock(transport->frontBio, blocking ? FALSE : TRUE))
      return FALSE;
  }

  return TRUE;
}

void transport_set_gateway_enabled(rdpTransport* transport, BOOL GatewayEnabled)
{
  WINPR_ASSERT(transport);
  transport->GatewayEnabled = GatewayEnabled;
}

void transport_set_nla_mode(rdpTransport* transport, BOOL NlaMode)
{
  WINPR_ASSERT(transport);
  transport->NlaMode = NlaMode;
}

void transport_set_rdstls_mode(rdpTransport* transport, BOOL RdstlsMode)
{
  WINPR_ASSERT(transport);
  transport->RdstlsMode = RdstlsMode;
}

void transport_set_aad_mode(rdpTransport* transport, BOOL AadMode)
{
  WINPR_ASSERT(transport);
  transport->AadMode = AadMode;
}

BOOL transport_disconnect(rdpTransport* transport)
{
  if (!transport)
    return FALSE;
  return IFCALLRESULT(FALSE, transport->io.TransportDisconnect, transport);
}

static BOOL transport_default_disconnect(rdpTransport* transport)
{
  BOOL status = TRUE;

  if (!transport)
    return FALSE;

  if (transport->tls)
  {
    freerdp_tls_free(transport->tls);
    transport->tls = NULL;
  }
  else
  {
    if (transport->frontBio)
      BIO_free_all(transport->frontBio);
  }

  if (transport->tsg)
  {
    tsg_free(transport->tsg);
    transport->tsg = NULL;
  }

  if (transport->rdg)
  {
    rdg_free(transport->rdg);
    transport->rdg = NULL;
  }

  if (transport->wst)
  {
    wst_free(transport->wst);
    transport->wst = NULL;
  }

  transport->frontBio = NULL;
  transport->layer = TRANSPORT_LAYER_TCP;
  transport->earlyUserAuth = FALSE;
  return status;
}

rdpTransport* transport_new(rdpContext* context)
{
  rdpTransport* transport = (rdpTransport*)calloc(1, sizeof(rdpTransport));

  WINPR_ASSERT(context);
  if (!transport)
    return NULL;

  transport->log = WLog_Get(TAG);

  if (!transport->log)
    goto fail;

  // transport->io.DataHandler = transport_data_handler;
  transport->io.TCPConnect = freerdp_tcp_default_connect;
  transport->io.TLSConnect = transport_default_connect_tls;
  transport->io.TLSAccept = transport_default_accept_tls;
  transport->io.TransportAttach = transport_default_attach;
  transport->io.TransportDisconnect = transport_default_disconnect;
  transport->io.ReadPdu = transport_default_read_pdu;
  transport->io.WritePdu = transport_default_write;
  transport->io.ReadBytes = transport_read_layer;

  transport->context = context;
  transport->ReceivePool = StreamPool_New(TRUE, BUFFER_SIZE);

  if (!transport->ReceivePool)
    goto fail;

  /* receive buffer for non-blocking read. */
  transport->ReceiveBuffer = StreamPool_Take(transport->ReceivePool, 0);

  if (!transport->ReceiveBuffer)
    goto fail;

  transport->connectedEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

  if (!transport->connectedEvent || transport->connectedEvent == INVALID_HANDLE_VALUE)
    goto fail;

  transport->rereadEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

  if (!transport->rereadEvent || transport->rereadEvent == INVALID_HANDLE_VALUE)
    goto fail;

  transport->ioEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

  if (!transport->ioEvent || transport->ioEvent == INVALID_HANDLE_VALUE)
    goto fail;

  transport->haveMoreBytesToRead = FALSE;
  transport->blocking = TRUE;
  transport->GatewayEnabled = FALSE;
  transport->layer = TRANSPORT_LAYER_TCP;

  if (!InitializeCriticalSectionAndSpinCount(&(transport->ReadLock), 4000))
    goto fail;

  if (!InitializeCriticalSectionAndSpinCount(&(transport->WriteLock), 4000))
    goto fail;

  return transport;
fail:
  transport_free(transport);
  return NULL;
}

void transport_free(rdpTransport* transport)
{
  if (!transport)
    return;

  transport_disconnect(transport);

  if (transport->ReceiveBuffer)
    Stream_Release(transport->ReceiveBuffer);

  nla_free(transport->nla);
  StreamPool_Free(transport->ReceivePool);
  CloseHandle(transport->connectedEvent);
  CloseHandle(transport->rereadEvent);
  CloseHandle(transport->ioEvent);
  DeleteCriticalSection(&(transport->ReadLock));
  DeleteCriticalSection(&(transport->WriteLock));
  free(transport);
}

BOOL transport_set_io_callbacks(rdpTransport* transport, const rdpTransportIo* io_callbacks)
{
  if (!transport || !io_callbacks)
    return FALSE;

  transport->io = *io_callbacks;
  return TRUE;
}

const rdpTransportIo* transport_get_io_callbacks(rdpTransport* transport)
{
  if (!transport)
    return NULL;
  return &transport->io;
}

rdpContext* transport_get_context(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->context;
}

rdpTransport* freerdp_get_transport(rdpContext* context)
{
  WINPR_ASSERT(context);
  WINPR_ASSERT(context->rdp);
  return context->rdp->transport;
}

BOOL transport_set_nla(rdpTransport* transport, rdpNla* nla)
{
  WINPR_ASSERT(transport);
  nla_free(transport->nla);
  transport->nla = nla;
  return TRUE;
}

rdpNla* transport_get_nla(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->nla;
}

BOOL transport_set_tls(rdpTransport* transport, rdpTls* tls)
{
  WINPR_ASSERT(transport);
  freerdp_tls_free(transport->tls);
  transport->tls = tls;
  return TRUE;
}

rdpTls* transport_get_tls(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->tls;
}

BOOL transport_set_tsg(rdpTransport* transport, rdpTsg* tsg)
{
  WINPR_ASSERT(transport);
  tsg_free(transport->tsg);
  transport->tsg = tsg;
  return TRUE;
}

rdpTsg* transport_get_tsg(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->tsg;
}

wStream* transport_take_from_pool(rdpTransport* transport, size_t size)
{
  WINPR_ASSERT(transport);
  return StreamPool_Take(transport->ReceivePool, size);
}

ULONG transport_get_bytes_sent(rdpTransport* transport, BOOL resetCount)
{
  ULONG rc;
  WINPR_ASSERT(transport);
  rc = transport->written;
  if (resetCount)
    transport->written = 0;
  return rc;
}

TRANSPORT_LAYER transport_get_layer(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->layer;
}

BOOL transport_set_layer(rdpTransport* transport, TRANSPORT_LAYER layer)
{
  WINPR_ASSERT(transport);
  transport->layer = layer;
  return TRUE;
}

BOOL transport_set_connected_event(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return SetEvent(transport->connectedEvent);
}

BOOL transport_set_recv_callbacks(rdpTransport* transport, TransportRecv recv, void* extra)
{
  WINPR_ASSERT(transport);
  transport->ReceiveCallback = recv;
  transport->ReceiveExtra = extra;
  return TRUE;
}

BOOL transport_get_blocking(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->blocking;
}

BOOL transport_set_blocking(rdpTransport* transport, BOOL blocking)
{
  WINPR_ASSERT(transport);
  transport->blocking = blocking;
  return TRUE;
}

BOOL transport_have_more_bytes_to_read(rdpTransport* transport)
{
  WINPR_ASSERT(transport);
  return transport->haveMoreBytesToRead;
}

int transport_tcp_connect(rdpTransport* transport, const char* hostname, int port, DWORD timeout)
{
  rdpContext* context = transport_get_context(transport);
  WINPR_ASSERT(context);
  WINPR_ASSERT(context->settings);
  return IFCALLRESULT(-1, transport->io.TCPConnect, context, context->settings, hostname, port,
                      timeout);
}

HANDLE transport_get_front_bio(rdpTransport* transport)
{
  HANDLE hEvent = NULL;
  WINPR_ASSERT(transport);
  WINPR_ASSERT(transport->frontBio);

  BIO_get_event(transport->frontBio, &hEvent);
  return hEvent;
}

BOOL transport_io_callback_set_event(rdpTransport* transport, BOOL set)
{
  WINPR_ASSERT(transport);
  transport->useIoEvent = TRUE;
  if (!set)
    return ResetEvent(transport->ioEvent);
  return SetEvent(transport->ioEvent);
}

void transport_set_early_user_auth_mode(rdpTransport* transport, BOOL EUAMode)
{
  WINPR_ASSERT(transport);
  transport->earlyUserAuth = EUAMode;
  WLog_Print(transport->log, WLOG_DEBUG, "Early User Auth Mode: %s", EUAMode ? "on" : "off");
}

Coverage Report

Created: 2023-11-27 07:17