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FreeRDP/libfreerdp/core/nego.c
Steve Pronovost 592f8d95be Fix connection negotiation with mstsc/msrdc 
mstsc/msrdc includes an optional correlation info
(RDP_NEG_CORRELATION_INFO) during connection negotiation. This confuses
FreeRDP which interpret this as a cookie and eventually fails the
negotiation, preventing a successful connection to these RDP client.

This commit addresses 3 things.

1) When processing connection token or cookie, skip if the remaining
bytes are neither.
2) After processing the RDP_NEG_REQ info, skip the optional correlation
info (RDP_NEG_CORRELATION_INFO) if one is present.
3) Allow local connection without server certificate when the client
inherently trust the server.
2021-10-21 13:11:21 +02:00

1549 lines
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/**
* FreeRDP: A Remote Desktop Protocol Implementation
* RDP Protocol Security Negotiation
*
* Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
* Copyright 2014 Norbert Federa <norbert.federa@thincast.com>
* Copyright 2015 Thincast Technologies GmbH
* Copyright 2015 DI (FH) Martin Haimberger <martin.haimberger@thincast.com>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <winpr/crt.h>
#include <winpr/assert.h>
#include <freerdp/log.h>
#include "tpkt.h"
#include "nego.h"
#include "transport.h"
#define TAG FREERDP_TAG("core.nego")
struct rdp_nego
{
UINT16 port;
UINT32 flags;
const char* hostname;
char* cookie;
BYTE* RoutingToken;
DWORD RoutingTokenLength;
BOOL SendPreconnectionPdu;
UINT32 PreconnectionId;
const char* PreconnectionBlob;
NEGO_STATE state;
BOOL TcpConnected;
BOOL SecurityConnected;
UINT32 CookieMaxLength;
BOOL sendNegoData;
UINT32 SelectedProtocol;
UINT32 RequestedProtocols;
BOOL NegotiateSecurityLayer;
BOOL EnabledProtocols[16];
BOOL RestrictedAdminModeRequired;
BOOL GatewayEnabled;
BOOL GatewayBypassLocal;
rdpTransport* transport;
};
static const char* nego_state_string(NEGO_STATE state)
{
static const char* const NEGO_STATE_STRINGS[] = { "NEGO_STATE_INITIAL", "NEGO_STATE_EXT",
"NEGO_STATE_NLA", "NEGO_STATE_TLS",
"NEGO_STATE_RDP", "NEGO_STATE_FAIL",
"NEGO_STATE_FINAL", "NEGO_STATE_INVALID" };
if (state >= ARRAYSIZE(NEGO_STATE_STRINGS))
return NEGO_STATE_STRINGS[ARRAYSIZE(NEGO_STATE_STRINGS) - 1];
return NEGO_STATE_STRINGS[state];
}
static const char* protocol_security_string(UINT32 security)
{
static const char* PROTOCOL_SECURITY_STRINGS[] = { "RDP", "TLS", "NLA", "UNK", "UNK",
"UNK", "UNK", "UNK", "EXT", "UNK" };
if (security >= ARRAYSIZE(PROTOCOL_SECURITY_STRINGS))
return PROTOCOL_SECURITY_STRINGS[ARRAYSIZE(PROTOCOL_SECURITY_STRINGS) - 1];
return PROTOCOL_SECURITY_STRINGS[security];
}
static BOOL nego_transport_connect(rdpNego* nego);
static BOOL nego_transport_disconnect(rdpNego* nego);
static BOOL nego_security_connect(rdpNego* nego);
static BOOL nego_send_preconnection_pdu(rdpNego* nego);
static BOOL nego_recv_response(rdpNego* nego);
static void nego_send(rdpNego* nego);
static BOOL nego_process_negotiation_request(rdpNego* nego, wStream* s);
static BOOL nego_process_negotiation_response(rdpNego* nego, wStream* s);
static BOOL nego_process_negotiation_failure(rdpNego* nego, wStream* s);
/**
* Negotiate protocol security and connect.
* @param nego
* @return
*/
BOOL nego_connect(rdpNego* nego)
{
rdpContext* context;
rdpSettings* settings;
WINPR_ASSERT(nego);
context = transport_get_context(nego->transport);
WINPR_ASSERT(context);
settings = context->settings;
WINPR_ASSERT(settings);
if (nego_get_state(nego) == NEGO_STATE_INITIAL)
{
if (nego->EnabledProtocols[PROTOCOL_HYBRID_EX])
{
nego_set_state(nego, NEGO_STATE_EXT);
}
else if (nego->EnabledProtocols[PROTOCOL_HYBRID])
{
nego_set_state(nego, NEGO_STATE_NLA);
}
else if (nego->EnabledProtocols[PROTOCOL_SSL])
{
nego_set_state(nego, NEGO_STATE_TLS);
}
else if (nego->EnabledProtocols[PROTOCOL_RDP])
{
nego_set_state(nego, NEGO_STATE_RDP);
}
else
{
WLog_ERR(TAG, "No security protocol is enabled");
nego_set_state(nego, NEGO_STATE_FAIL);
return FALSE;
}
if (!nego->NegotiateSecurityLayer)
{
WLog_DBG(TAG, "Security Layer Negotiation is disabled");
/* attempt only the highest enabled protocol (see nego_attempt_*) */
nego->EnabledProtocols[PROTOCOL_HYBRID] = FALSE;
nego->EnabledProtocols[PROTOCOL_SSL] = FALSE;
nego->EnabledProtocols[PROTOCOL_RDP] = FALSE;
nego->EnabledProtocols[PROTOCOL_HYBRID_EX] = FALSE;
switch (nego_get_state(nego))
{
case NEGO_STATE_EXT:
nego->EnabledProtocols[PROTOCOL_HYBRID_EX] = TRUE;
nego->EnabledProtocols[PROTOCOL_HYBRID] = TRUE;
nego->SelectedProtocol = PROTOCOL_HYBRID_EX;
break;
case NEGO_STATE_NLA:
nego->EnabledProtocols[PROTOCOL_HYBRID] = TRUE;
nego->SelectedProtocol = PROTOCOL_HYBRID;
break;
case NEGO_STATE_TLS:
nego->EnabledProtocols[PROTOCOL_SSL] = TRUE;
nego->SelectedProtocol = PROTOCOL_SSL;
break;
case NEGO_STATE_RDP:
nego->EnabledProtocols[PROTOCOL_RDP] = TRUE;
nego->SelectedProtocol = PROTOCOL_RDP;
break;
default:
WLog_ERR(TAG, "Invalid NEGO state 0x%08" PRIx32, nego_get_state(nego));
return FALSE;
}
}
if (nego->SendPreconnectionPdu)
{
if (!nego_send_preconnection_pdu(nego))
{
WLog_ERR(TAG, "Failed to send preconnection pdu");
nego_set_state(nego, NEGO_STATE_FINAL);
return FALSE;
}
}
}
if (!nego->NegotiateSecurityLayer)
{
nego_set_state(nego, NEGO_STATE_FINAL);
}
else
{
do
{
WLog_DBG(TAG, "state: %s", nego_state_string(nego_get_state(nego)));
nego_send(nego);
if (nego_get_state(nego) == NEGO_STATE_FAIL)
{
if (freerdp_get_last_error(transport_get_context(nego->transport)) ==
FREERDP_ERROR_SUCCESS)
WLog_ERR(TAG, "Protocol Security Negotiation Failure");
nego_set_state(nego, NEGO_STATE_FINAL);
return FALSE;
}
} while (nego_get_state(nego) != NEGO_STATE_FINAL);
}
WLog_DBG(TAG, "Negotiated %s security", protocol_security_string(nego->SelectedProtocol));
/* update settings with negotiated protocol security */
settings->RequestedProtocols = nego->RequestedProtocols;
settings->SelectedProtocol = nego->SelectedProtocol;
settings->NegotiationFlags = nego->flags;
if (nego->SelectedProtocol == PROTOCOL_RDP)
{
settings->UseRdpSecurityLayer = TRUE;
if (!settings->EncryptionMethods)
{
/**
* Advertise all supported encryption methods if the client
* implementation did not set any security methods
*/
settings->EncryptionMethods = ENCRYPTION_METHOD_40BIT | ENCRYPTION_METHOD_56BIT |
ENCRYPTION_METHOD_128BIT | ENCRYPTION_METHOD_FIPS;
}
}
/* finally connect security layer (if not already done) */
if (!nego_security_connect(nego))
{
WLog_DBG(TAG, "Failed to connect with %s security",
protocol_security_string(nego->SelectedProtocol));
return FALSE;
}
return TRUE;
}
BOOL nego_disconnect(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego_set_state(nego, NEGO_STATE_INITIAL);
return nego_transport_disconnect(nego);
}
/* connect to selected security layer */
BOOL nego_security_connect(rdpNego* nego)
{
WINPR_ASSERT(nego);
if (!nego->TcpConnected)
{
nego->SecurityConnected = FALSE;
}
else if (!nego->SecurityConnected)
{
if (nego->SelectedProtocol == PROTOCOL_HYBRID)
{
WLog_DBG(TAG, "nego_security_connect with PROTOCOL_HYBRID");
nego->SecurityConnected = transport_connect_nla(nego->transport);
}
else if (nego->SelectedProtocol == PROTOCOL_SSL)
{
WLog_DBG(TAG, "nego_security_connect with PROTOCOL_SSL");
nego->SecurityConnected = transport_connect_tls(nego->transport);
}
else if (nego->SelectedProtocol == PROTOCOL_RDP)
{
WLog_DBG(TAG, "nego_security_connect with PROTOCOL_RDP");
nego->SecurityConnected = transport_connect_rdp(nego->transport);
}
else
{
WLog_ERR(TAG,
"cannot connect security layer because no protocol has been selected yet.");
}
}
return nego->SecurityConnected;
}
/**
* Connect TCP layer.
* @param nego
* @return
*/
static BOOL nego_tcp_connect(rdpNego* nego)
{
rdpContext* context;
WINPR_ASSERT(nego);
if (!nego->TcpConnected)
{
UINT32 TcpConnectTimeout;
context = transport_get_context(nego->transport);
WINPR_ASSERT(context);
TcpConnectTimeout =
freerdp_settings_get_uint32(context->settings, FreeRDP_TcpConnectTimeout);
if (nego->GatewayEnabled)
{
if (nego->GatewayBypassLocal)
{
/* Attempt a direct connection first, and then fallback to using the gateway */
WLog_INFO(TAG,
"Detecting if host can be reached locally. - This might take some time.");
WLog_INFO(TAG, "To disable auto detection use /gateway-usage-method:direct");
transport_set_gateway_enabled(nego->transport, FALSE);
nego->TcpConnected = transport_connect(nego->transport, nego->hostname, nego->port,
TcpConnectTimeout);
}
if (!nego->TcpConnected)
{
transport_set_gateway_enabled(nego->transport, TRUE);
nego->TcpConnected = transport_connect(nego->transport, nego->hostname, nego->port,
TcpConnectTimeout);
}
}
else
{
nego->TcpConnected =
transport_connect(nego->transport, nego->hostname, nego->port, TcpConnectTimeout);
}
}
return nego->TcpConnected;
}
/**
* Connect TCP layer. For direct approach, connect security layer as well.
* @param nego
* @return
*/
BOOL nego_transport_connect(rdpNego* nego)
{
WINPR_ASSERT(nego);
if (!nego_tcp_connect(nego))
return FALSE;
if (nego->TcpConnected && !nego->NegotiateSecurityLayer)
return nego_security_connect(nego);
return nego->TcpConnected;
}
/**
* Disconnect TCP layer.
* @param nego
* @return
*/
BOOL nego_transport_disconnect(rdpNego* nego)
{
WINPR_ASSERT(nego);
if (nego->TcpConnected)
transport_disconnect(nego->transport);
nego->TcpConnected = FALSE;
nego->SecurityConnected = FALSE;
return TRUE;
}
/**
* Send preconnection information if enabled.
* @param nego
* @return
*/
BOOL nego_send_preconnection_pdu(rdpNego* nego)
{
wStream* s;
UINT32 cbSize;
UINT16 cchPCB = 0;
WCHAR* wszPCB = NULL;
WINPR_ASSERT(nego);
WLog_DBG(TAG, "Sending preconnection PDU");
if (!nego_tcp_connect(nego))
return FALSE;
/* it's easier to always send the version 2 PDU, and it's just 2 bytes overhead */
cbSize = PRECONNECTION_PDU_V2_MIN_SIZE;
if (nego->PreconnectionBlob)
{
cchPCB = (UINT16)ConvertToUnicode(CP_UTF8, 0, nego->PreconnectionBlob, -1, &wszPCB, 0);
cchPCB += 1; /* zero-termination */
cbSize += cchPCB * 2;
}
s = Stream_New(NULL, cbSize);
if (!s)
{
free(wszPCB);
WLog_ERR(TAG, "Stream_New failed!");
return FALSE;
}
Stream_Write_UINT32(s, cbSize); /* cbSize */
Stream_Write_UINT32(s, 0); /* Flags */
Stream_Write_UINT32(s, PRECONNECTION_PDU_V2); /* Version */
Stream_Write_UINT32(s, nego->PreconnectionId); /* Id */
Stream_Write_UINT16(s, cchPCB); /* cchPCB */
if (wszPCB)
{
Stream_Write(s, wszPCB, cchPCB * 2); /* wszPCB */
free(wszPCB);
}
Stream_SealLength(s);
if (transport_write(nego->transport, s) < 0)
{
Stream_Free(s, TRUE);
return FALSE;
}
Stream_Free(s, TRUE);
return TRUE;
}
/**
* Attempt negotiating NLA + TLS extended security.
* @param nego
*/
static void nego_attempt_ext(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego->RequestedProtocols = PROTOCOL_HYBRID | PROTOCOL_SSL | PROTOCOL_HYBRID_EX;
WLog_DBG(TAG, "Attempting NLA extended security");
if (!nego_transport_connect(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_send_negotiation_request(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_recv_response(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
WLog_DBG(TAG, "state: %s", nego_state_string(nego_get_state(nego)));
if (nego_get_state(nego) != NEGO_STATE_FINAL)
{
nego_transport_disconnect(nego);
if (nego->EnabledProtocols[PROTOCOL_HYBRID])
nego_set_state(nego, NEGO_STATE_NLA);
else if (nego->EnabledProtocols[PROTOCOL_SSL])
nego_set_state(nego, NEGO_STATE_TLS);
else if (nego->EnabledProtocols[PROTOCOL_RDP])
nego_set_state(nego, NEGO_STATE_RDP);
else
nego_set_state(nego, NEGO_STATE_FAIL);
}
}
/**
* Attempt negotiating NLA + TLS security.
* @param nego
*/
static void nego_attempt_nla(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego->RequestedProtocols = PROTOCOL_HYBRID | PROTOCOL_SSL;
WLog_DBG(TAG, "Attempting NLA security");
if (!nego_transport_connect(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_send_negotiation_request(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_recv_response(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
WLog_DBG(TAG, "state: %s", nego_state_string(nego_get_state(nego)));
if (nego_get_state(nego) != NEGO_STATE_FINAL)
{
nego_transport_disconnect(nego);
if (nego->EnabledProtocols[PROTOCOL_SSL])
nego_set_state(nego, NEGO_STATE_TLS);
else if (nego->EnabledProtocols[PROTOCOL_RDP])
nego_set_state(nego, NEGO_STATE_RDP);
else
nego_set_state(nego, NEGO_STATE_FAIL);
}
}
/**
* Attempt negotiating TLS security.
* @param nego
*/
static void nego_attempt_tls(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego->RequestedProtocols = PROTOCOL_SSL;
WLog_DBG(TAG, "Attempting TLS security");
if (!nego_transport_connect(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_send_negotiation_request(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_recv_response(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (nego_get_state(nego) != NEGO_STATE_FINAL)
{
nego_transport_disconnect(nego);
if (nego->EnabledProtocols[PROTOCOL_RDP])
nego_set_state(nego, NEGO_STATE_RDP);
else
nego_set_state(nego, NEGO_STATE_FAIL);
}
}
/**
* Attempt negotiating standard RDP security.
* @param nego
*/
static void nego_attempt_rdp(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego->RequestedProtocols = PROTOCOL_RDP;
WLog_DBG(TAG, "Attempting RDP security");
if (!nego_transport_connect(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_send_negotiation_request(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
if (!nego_recv_response(nego))
{
nego_set_state(nego, NEGO_STATE_FAIL);
return;
}
}
/**
* Wait to receive a negotiation response
* @param nego
*/
BOOL nego_recv_response(rdpNego* nego)
{
int status;
wStream* s;
WINPR_ASSERT(nego);
s = Stream_New(NULL, 1024);
if (!s)
{
WLog_ERR(TAG, "Stream_New failed!");
return FALSE;
}
status = transport_read_pdu(nego->transport, s);
if (status < 0)
{
Stream_Free(s, TRUE);
return FALSE;
}
status = nego_recv(nego->transport, s, nego);
Stream_Free(s, TRUE);
if (status < 0)
return FALSE;
return TRUE;
}
/**
* Receive protocol security negotiation message.\n
* @msdn{cc240501}
* @param transport transport
* @param s stream
* @param extra nego pointer
*/
int nego_recv(rdpTransport* transport, wStream* s, void* extra)
{
BYTE li;
BYTE type;
UINT16 length;
rdpNego* nego = (rdpNego*)extra;
WINPR_ASSERT(nego);
if (!tpkt_read_header(s, &length))
return -1;
if (!tpdu_read_connection_confirm(s, &li, length))
return -1;
if (li > 6)
{
/* rdpNegData (optional) */
Stream_Read_UINT8(s, type); /* Type */
switch (type)
{
case TYPE_RDP_NEG_RSP:
if (!nego_process_negotiation_response(nego, s))
return -1;
WLog_DBG(TAG, "selected_protocol: %" PRIu32 "", nego->SelectedProtocol);
/* enhanced security selected ? */
if (nego->SelectedProtocol)
{
if ((nego->SelectedProtocol == PROTOCOL_HYBRID) &&
(!nego->EnabledProtocols[PROTOCOL_HYBRID]))
{
nego_set_state(nego, NEGO_STATE_FAIL);
}
if ((nego->SelectedProtocol == PROTOCOL_SSL) &&
(!nego->EnabledProtocols[PROTOCOL_SSL]))
{
nego_set_state(nego, NEGO_STATE_FAIL);
}
}
else if (!nego->EnabledProtocols[PROTOCOL_RDP])
{
nego_set_state(nego, NEGO_STATE_FAIL);
}
break;
case TYPE_RDP_NEG_FAILURE:
if (!nego_process_negotiation_failure(nego, s))
return -1;
break;
}
}
else if (li == 6)
{
WLog_DBG(TAG, "no rdpNegData");
if (!nego->EnabledProtocols[PROTOCOL_RDP])
nego_set_state(nego, NEGO_STATE_FAIL);
else
nego_set_state(nego, NEGO_STATE_FINAL);
}
else
{
WLog_ERR(TAG, "invalid negotiation response");
nego_set_state(nego, NEGO_STATE_FAIL);
}
if (!tpkt_ensure_stream_consumed(s, length))
return -1;
return 0;
}
/**
* Read optional routing token or cookie of X.224 Connection Request PDU.
* @msdn{cc240470}
* @param nego
* @param s stream
*/
static BOOL nego_read_request_token_or_cookie(rdpNego* nego, wStream* s)
{
/* routingToken and cookie are optional and mutually exclusive!
*
* routingToken (variable): An optional and variable-length routing
* token (used for load balancing) terminated by a 0x0D0A two-byte
* sequence: (check [MSFT-SDLBTS] for details!)
* Cookie:[space]msts=[ip address].[port].[reserved][\x0D\x0A]
*
* cookie (variable): An optional and variable-length ANSI character
* string terminated by a 0x0D0A two-byte sequence:
* Cookie:[space]mstshash=[ANSISTRING][\x0D\x0A]
*/
BYTE* str = NULL;
UINT16 crlf = 0;
size_t pos, len;
BOOL result = FALSE;
BOOL isToken = FALSE;
size_t remain = Stream_GetRemainingLength(s);
WINPR_ASSERT(nego);
str = Stream_Pointer(s);
pos = Stream_GetPosition(s);
/* minimum length for token is 15 */
if (remain < 15)
return TRUE;
if (memcmp(Stream_Pointer(s), "Cookie: mstshash=", 17) != 0)
{
if (memcmp(Stream_Pointer(s), "Cookie: msts=", 13) != 0)
{
/* remaining bytes are neither a token nor a cookie */
return TRUE;
}
isToken = TRUE;
}
else
{
/* not a token, minimum length for cookie is 19 */
if (remain < 19)
return TRUE;
Stream_Seek(s, 17);
}
while ((remain = Stream_GetRemainingLength(s)) >= 2)
{
Stream_Read_UINT16(s, crlf);
if (crlf == 0x0A0D)
break;
Stream_Rewind(s, 1);
}
if (crlf == 0x0A0D)
{
Stream_Rewind(s, 2);
len = Stream_GetPosition(s) - pos;
remain = Stream_GetRemainingLength(s);
Stream_Write_UINT16(s, 0);
if (strnlen((char*)str, len) == len)
{
if (isToken)
result = nego_set_routing_token(nego, str, len);
else
result = nego_set_cookie(nego, (char*)str);
}
}
if (!result)
{
Stream_SetPosition(s, pos);
WLog_ERR(TAG, "invalid %s received", isToken ? "routing token" : "cookie");
}
else
{
WLog_DBG(TAG, "received %s [%s]", isToken ? "routing token" : "cookie", str);
}
return result;
}
/**
* Read protocol security negotiation request message.\n
* @param nego
* @param s stream
*/
BOOL nego_read_request(rdpNego* nego, wStream* s)
{
BYTE li;
BYTE type;
UINT16 length;
WINPR_ASSERT(nego);
WINPR_ASSERT(s);
if (!tpkt_read_header(s, &length))
return FALSE;
if (!tpdu_read_connection_request(s, &li, length))
return FALSE;
if (li != Stream_GetRemainingLength(s) + 6)
{
WLog_ERR(TAG, "Incorrect TPDU length indicator.");
return FALSE;
}
if (!nego_read_request_token_or_cookie(nego, s))
{
WLog_ERR(TAG, "Failed to parse routing token or cookie.");
return FALSE;
}
if (Stream_GetRemainingLength(s) >= 8)
{
/* rdpNegData (optional) */
Stream_Read_UINT8(s, type); /* Type */
if (type != TYPE_RDP_NEG_REQ)
{
WLog_ERR(TAG, "Incorrect negotiation request type %" PRIu8 "", type);
return FALSE;
}
if (!nego_process_negotiation_request(nego, s))
return FALSE;
}
/* Skip over optional RDP_NEG_CORRELATION_INFO
* see MS-RDPBCGR 2.2.1.1.2 RDP Correlation Info (RDP_NEG_CORRELATION_INFO)
*/
if (Stream_GetRemainingLength(s) >= 36)
{
Stream_Seek(s, 36);
}
return tpkt_ensure_stream_consumed(s, length);
}
/**
* Send protocol security negotiation message.
* @param nego
*/
void nego_send(rdpNego* nego)
{
WINPR_ASSERT(nego);
switch (nego_get_state(nego))
{
case NEGO_STATE_EXT:
nego_attempt_ext(nego);
break;
case NEGO_STATE_NLA:
nego_attempt_nla(nego);
break;
case NEGO_STATE_TLS:
nego_attempt_tls(nego);
break;
case NEGO_STATE_RDP:
nego_attempt_rdp(nego);
break;
default:
WLog_ERR(TAG, "invalid negotiation state for sending");
break;
}
}
/**
* Send RDP Negotiation Request (RDP_NEG_REQ).\n
* @msdn{cc240500}\n
* @msdn{cc240470}
* @param nego
*/
BOOL nego_send_negotiation_request(rdpNego* nego)
{
BOOL rc = FALSE;
wStream* s;
size_t length;
size_t bm, em;
BYTE flags = 0;
size_t cookie_length;
s = Stream_New(NULL, 512);
WINPR_ASSERT(nego);
if (!s)
{
WLog_ERR(TAG, "Stream_New failed!");
return FALSE;
}
length = TPDU_CONNECTION_REQUEST_LENGTH;
bm = Stream_GetPosition(s);
Stream_Seek(s, length);
if (nego->RoutingToken)
{
Stream_Write(s, nego->RoutingToken, nego->RoutingTokenLength);
/* Ensure Routing Token is correctly terminated - may already be present in string */
if ((nego->RoutingTokenLength > 2) &&
(nego->RoutingToken[nego->RoutingTokenLength - 2] == 0x0D) &&
(nego->RoutingToken[nego->RoutingTokenLength - 1] == 0x0A))
{
WLog_DBG(TAG, "Routing token looks correctly terminated - use verbatim");
length += nego->RoutingTokenLength;
}
else
{
WLog_DBG(TAG, "Adding terminating CRLF to routing token");
Stream_Write_UINT8(s, 0x0D); /* CR */
Stream_Write_UINT8(s, 0x0A); /* LF */
length += nego->RoutingTokenLength + 2;
}
}
else if (nego->cookie)
{
cookie_length = strlen(nego->cookie);
if (cookie_length > nego->CookieMaxLength)
cookie_length = nego->CookieMaxLength;
Stream_Write(s, "Cookie: mstshash=", 17);
Stream_Write(s, (BYTE*)nego->cookie, cookie_length);
Stream_Write_UINT8(s, 0x0D); /* CR */
Stream_Write_UINT8(s, 0x0A); /* LF */
length += cookie_length + 19;
}
WLog_DBG(TAG, "RequestedProtocols: %" PRIu32 "", nego->RequestedProtocols);
if ((nego->RequestedProtocols > PROTOCOL_RDP) || (nego->sendNegoData))
{
/* RDP_NEG_DATA must be present for TLS and NLA */
if (nego->RestrictedAdminModeRequired)
flags |= RESTRICTED_ADMIN_MODE_REQUIRED;
Stream_Write_UINT8(s, TYPE_RDP_NEG_REQ);
Stream_Write_UINT8(s, flags);
Stream_Write_UINT16(s, 8); /* RDP_NEG_DATA length (8) */
Stream_Write_UINT32(s, nego->RequestedProtocols); /* requestedProtocols */
length += 8;
}
if (length > UINT16_MAX)
goto fail;
em = Stream_GetPosition(s);
Stream_SetPosition(s, bm);
tpkt_write_header(s, (UINT16)length);
tpdu_write_connection_request(s, (UINT16)length - 5);
Stream_SetPosition(s, em);
Stream_SealLength(s);
rc = (transport_write(nego->transport, s) >= 0);
fail:
Stream_Free(s, TRUE);
return rc;
}
/**
* Process Negotiation Request from Connection Request message.
* @param nego
* @param s
*/
BOOL nego_process_negotiation_request(rdpNego* nego, wStream* s)
{
BYTE flags;
UINT16 length;
WINPR_ASSERT(nego);
WINPR_ASSERT(s);
if (Stream_GetRemainingLength(s) < 7)
return FALSE;
Stream_Read_UINT8(s, flags);
Stream_Read_UINT16(s, length);
Stream_Read_UINT32(s, nego->RequestedProtocols);
WLog_DBG(TAG, "RDP_NEG_REQ: RequestedProtocol: 0x%08" PRIX32 "", nego->RequestedProtocols);
nego_set_state(nego, NEGO_STATE_FINAL);
return TRUE;
}
/**
* Process Negotiation Response from Connection Confirm message.
* @param nego
* @param s
*/
BOOL nego_process_negotiation_response(rdpNego* nego, wStream* s)
{
UINT16 length;
WLog_DBG(TAG, "RDP_NEG_RSP");
WINPR_ASSERT(nego);
WINPR_ASSERT(s);
if (Stream_GetRemainingLength(s) < 7)
{
WLog_ERR(TAG, "Invalid RDP_NEG_RSP");
nego_set_state(nego, NEGO_STATE_FAIL);
return FALSE;
}
Stream_Read_UINT8(s, nego->flags);
Stream_Read_UINT16(s, length);
Stream_Read_UINT32(s, nego->SelectedProtocol);
nego_set_state(nego, NEGO_STATE_FINAL);
return TRUE;
}
/**
* Process Negotiation Failure from Connection Confirm message.
* @param nego
* @param s
*/
BOOL nego_process_negotiation_failure(rdpNego* nego, wStream* s)
{
BYTE flags;
UINT16 length;
UINT32 failureCode;
WINPR_ASSERT(nego);
WINPR_ASSERT(s);
WLog_DBG(TAG, "RDP_NEG_FAILURE");
if (Stream_GetRemainingLength(s) < 7)
return FALSE;
Stream_Read_UINT8(s, flags);
Stream_Read_UINT16(s, length);
Stream_Read_UINT32(s, failureCode);
switch (failureCode)
{
case SSL_REQUIRED_BY_SERVER:
WLog_WARN(TAG, "Error: SSL_REQUIRED_BY_SERVER");
break;
case SSL_NOT_ALLOWED_BY_SERVER:
WLog_WARN(TAG, "Error: SSL_NOT_ALLOWED_BY_SERVER");
nego->sendNegoData = TRUE;
break;
case SSL_CERT_NOT_ON_SERVER:
WLog_ERR(TAG, "Error: SSL_CERT_NOT_ON_SERVER");
nego->sendNegoData = TRUE;
break;
case INCONSISTENT_FLAGS:
WLog_ERR(TAG, "Error: INCONSISTENT_FLAGS");
break;
case HYBRID_REQUIRED_BY_SERVER:
WLog_WARN(TAG, "Error: HYBRID_REQUIRED_BY_SERVER");
break;
default:
WLog_ERR(TAG, "Error: Unknown protocol security error %" PRIu32 "", failureCode);
break;
}
nego_set_state(nego, NEGO_STATE_FAIL);
return TRUE;
}
/**
* Send RDP Negotiation Response (RDP_NEG_RSP).\n
* @param nego
*/
BOOL nego_send_negotiation_response(rdpNego* nego)
{
UINT16 length;
size_t bm, em;
BOOL status;
wStream* s;
BYTE flags;
rdpContext* context;
rdpSettings* settings;
WINPR_ASSERT(nego);
context = transport_get_context(nego->transport);
WINPR_ASSERT(context);
settings = context->settings;
WINPR_ASSERT(settings);
status = TRUE;
s = Stream_New(NULL, 512);
if (!s)
{
WLog_ERR(TAG, "Stream_New failed!");
return FALSE;
}
length = TPDU_CONNECTION_CONFIRM_LENGTH;
bm = Stream_GetPosition(s);
Stream_Seek(s, length);
if (nego->SelectedProtocol & PROTOCOL_FAILED_NEGO)
{
UINT32 errorCode = (nego->SelectedProtocol & ~PROTOCOL_FAILED_NEGO);
flags = 0;
Stream_Write_UINT8(s, TYPE_RDP_NEG_FAILURE);
Stream_Write_UINT8(s, flags); /* flags */
Stream_Write_UINT16(s, 8); /* RDP_NEG_DATA length (8) */
Stream_Write_UINT32(s, errorCode);
length += 8;
status = FALSE;
}
else
{
flags = EXTENDED_CLIENT_DATA_SUPPORTED;
if (settings->SupportGraphicsPipeline)
flags |= DYNVC_GFX_PROTOCOL_SUPPORTED;
/* RDP_NEG_DATA must be present for TLS, NLA, and RDP */
Stream_Write_UINT8(s, TYPE_RDP_NEG_RSP);
Stream_Write_UINT8(s, flags); /* flags */
Stream_Write_UINT16(s, 8); /* RDP_NEG_DATA length (8) */
Stream_Write_UINT32(s, nego->SelectedProtocol); /* selectedProtocol */
length += 8;
}
em = Stream_GetPosition(s);
Stream_SetPosition(s, bm);
status = tpkt_write_header(s, length);
if (status)
{
tpdu_write_connection_confirm(s, length - 5);
Stream_SetPosition(s, em);
Stream_SealLength(s);
status = (transport_write(nego->transport, s) >= 0);
}
Stream_Free(s, TRUE);
if (status)
{
/* update settings with negotiated protocol security */
settings->RequestedProtocols = nego->RequestedProtocols;
settings->SelectedProtocol = nego->SelectedProtocol;
if (settings->SelectedProtocol == PROTOCOL_RDP)
{
settings->TlsSecurity = FALSE;
settings->NlaSecurity = FALSE;
settings->RdpSecurity = TRUE;
settings->UseRdpSecurityLayer = TRUE;
if (settings->EncryptionLevel == ENCRYPTION_LEVEL_NONE)
{
/**
* If the server implementation did not explicitely set a
* encryption level we default to client compatible
*/
settings->EncryptionLevel = ENCRYPTION_LEVEL_CLIENT_COMPATIBLE;
}
if (settings->LocalConnection)
{
/**
* Note: This hack was firstly introduced in commit 95f5e115 to
* disable the unnecessary encryption with peers connecting to
* 127.0.0.1 or local unix sockets.
* This also affects connections via port tunnels! (e.g. ssh -L)
*/
WLog_INFO(TAG, "Turning off encryption for local peer with standard rdp security");
settings->UseRdpSecurityLayer = FALSE;
settings->EncryptionLevel = ENCRYPTION_LEVEL_NONE;
}
else if (!settings->RdpServerRsaKey && !settings->RdpKeyFile &&
!settings->RdpKeyContent)
{
WLog_ERR(TAG, "Missing server certificate");
return FALSE;
}
}
else if (settings->SelectedProtocol == PROTOCOL_SSL)
{
settings->TlsSecurity = TRUE;
settings->NlaSecurity = FALSE;
settings->RdpSecurity = FALSE;
settings->UseRdpSecurityLayer = FALSE;
settings->EncryptionLevel = ENCRYPTION_LEVEL_NONE;
}
else if (settings->SelectedProtocol == PROTOCOL_HYBRID)
{
settings->TlsSecurity = TRUE;
settings->NlaSecurity = TRUE;
settings->RdpSecurity = FALSE;
settings->UseRdpSecurityLayer = FALSE;
settings->EncryptionLevel = ENCRYPTION_LEVEL_NONE;
}
}
return status;
}
/**
* Initialize NEGO state machine.
* @param nego
*/
void nego_init(rdpNego* nego)
{
WINPR_ASSERT(nego);
nego_set_state(nego, NEGO_STATE_INITIAL);
nego->RequestedProtocols = PROTOCOL_RDP;
nego->CookieMaxLength = DEFAULT_COOKIE_MAX_LENGTH;
nego->sendNegoData = FALSE;
nego->flags = 0;
}
/**
* Create a new NEGO state machine instance.
* @param transport
* @return
*/
rdpNego* nego_new(rdpTransport* transport)
{
rdpNego* nego = (rdpNego*)calloc(1, sizeof(rdpNego));
if (!nego)
return NULL;
nego->transport = transport;
nego_init(nego);
return nego;
}
/**
* Free NEGO state machine.
* @param nego
*/
void nego_free(rdpNego* nego)
{
if (nego)
{
free(nego->RoutingToken);
free(nego->cookie);
free(nego);
}
}
/**
* Set target hostname and port.
* @param nego
* @param hostname
* @param port
*/
BOOL nego_set_target(rdpNego* nego, const char* hostname, UINT16 port)
{
if (!nego || !hostname)
return FALSE;
nego->hostname = hostname;
nego->port = port;
return TRUE;
}
/**
* Enable security layer negotiation.
* @param nego pointer to the negotiation structure
* @param enable_rdp whether to enable security layer negotiation (TRUE for enabled, FALSE for
* disabled)
*/
void nego_set_negotiation_enabled(rdpNego* nego, BOOL NegotiateSecurityLayer)
{
WLog_DBG(TAG, "Enabling security layer negotiation: %s",
NegotiateSecurityLayer ? "TRUE" : "FALSE");
nego->NegotiateSecurityLayer = NegotiateSecurityLayer;
}
/**
* Enable restricted admin mode.
* @param nego pointer to the negotiation structure
* @param enable_restricted whether to enable security layer negotiation (TRUE for enabled, FALSE
* for disabled)
*/
void nego_set_restricted_admin_mode_required(rdpNego* nego, BOOL RestrictedAdminModeRequired)
{
WLog_DBG(TAG, "Enabling restricted admin mode: %s",
RestrictedAdminModeRequired ? "TRUE" : "FALSE");
nego->RestrictedAdminModeRequired = RestrictedAdminModeRequired;
}
void nego_set_gateway_enabled(rdpNego* nego, BOOL GatewayEnabled)
{
nego->GatewayEnabled = GatewayEnabled;
}
void nego_set_gateway_bypass_local(rdpNego* nego, BOOL GatewayBypassLocal)
{
nego->GatewayBypassLocal = GatewayBypassLocal;
}
/**
* Enable RDP security protocol.
* @param nego pointer to the negotiation structure
* @param enable_rdp whether to enable normal RDP protocol (TRUE for enabled, FALSE for disabled)
*/
void nego_enable_rdp(rdpNego* nego, BOOL enable_rdp)
{
WLog_DBG(TAG, "Enabling RDP security: %s", enable_rdp ? "TRUE" : "FALSE");
nego->EnabledProtocols[PROTOCOL_RDP] = enable_rdp;
}
/**
* Enable TLS security protocol.
* @param nego pointer to the negotiation structure
* @param enable_tls whether to enable TLS + RDP protocol (TRUE for enabled, FALSE for disabled)
*/
void nego_enable_tls(rdpNego* nego, BOOL enable_tls)
{
WLog_DBG(TAG, "Enabling TLS security: %s", enable_tls ? "TRUE" : "FALSE");
nego->EnabledProtocols[PROTOCOL_SSL] = enable_tls;
}
/**
* Enable NLA security protocol.
* @param nego pointer to the negotiation structure
* @param enable_nla whether to enable network level authentication protocol (TRUE for enabled,
* FALSE for disabled)
*/
void nego_enable_nla(rdpNego* nego, BOOL enable_nla)
{
WLog_DBG(TAG, "Enabling NLA security: %s", enable_nla ? "TRUE" : "FALSE");
nego->EnabledProtocols[PROTOCOL_HYBRID] = enable_nla;
}
/**
* Enable NLA extended security protocol.
* @param nego pointer to the negotiation structure
* @param enable_ext whether to enable network level authentication extended protocol (TRUE for
* enabled, FALSE for disabled)
*/
void nego_enable_ext(rdpNego* nego, BOOL enable_ext)
{
WLog_DBG(TAG, "Enabling NLA extended security: %s", enable_ext ? "TRUE" : "FALSE");
nego->EnabledProtocols[PROTOCOL_HYBRID_EX] = enable_ext;
}
/**
* Set routing token.
* @param nego
* @param RoutingToken
* @param RoutingTokenLength
*/
BOOL nego_set_routing_token(rdpNego* nego, const BYTE* RoutingToken, DWORD RoutingTokenLength)
{
if (RoutingTokenLength == 0)
return FALSE;
free(nego->RoutingToken);
nego->RoutingTokenLength = RoutingTokenLength;
nego->RoutingToken = (BYTE*)malloc(nego->RoutingTokenLength);
if (!nego->RoutingToken)
return FALSE;
CopyMemory(nego->RoutingToken, RoutingToken, nego->RoutingTokenLength);
return TRUE;
}
/**
* Set cookie.
* @param nego
* @param cookie
*/
BOOL nego_set_cookie(rdpNego* nego, const char* cookie)
{
if (nego->cookie)
{
free(nego->cookie);
nego->cookie = NULL;
}
if (!cookie)
return TRUE;
nego->cookie = _strdup(cookie);
if (!nego->cookie)
return FALSE;
return TRUE;
}
/**
* Set cookie maximum length
* @param nego
* @param CookieMaxLength
*/
void nego_set_cookie_max_length(rdpNego* nego, UINT32 CookieMaxLength)
{
nego->CookieMaxLength = CookieMaxLength;
}
/**
* Enable / disable preconnection PDU.
* @param nego
* @param send_pcpdu
*/
void nego_set_send_preconnection_pdu(rdpNego* nego, BOOL SendPreconnectionPdu)
{
nego->SendPreconnectionPdu = SendPreconnectionPdu;
}
/**
* Set preconnection id.
* @param nego
* @param id
*/
void nego_set_preconnection_id(rdpNego* nego, UINT32 PreconnectionId)
{
nego->PreconnectionId = PreconnectionId;
}
/**
* Set preconnection blob.
* @param nego
* @param blob
*/
void nego_set_preconnection_blob(rdpNego* nego, const char* PreconnectionBlob)
{
nego->PreconnectionBlob = PreconnectionBlob;
}
UINT32 nego_get_selected_protocol(rdpNego* nego)
{
if (!nego)
return 0;
return nego->SelectedProtocol;
}
BOOL nego_set_selected_protocol(rdpNego* nego, UINT32 SelectedProtocol)
{
if (!nego)
return FALSE;
nego->SelectedProtocol = SelectedProtocol;
return TRUE;
}
UINT32 nego_get_requested_protocols(rdpNego* nego)
{
if (!nego)
return 0;
return nego->RequestedProtocols;
}
BOOL nego_set_requested_protocols(rdpNego* nego, UINT32 RequestedProtocols)
{
if (!nego)
return FALSE;
nego->RequestedProtocols = RequestedProtocols;
return TRUE;
}
NEGO_STATE nego_get_state(rdpNego* nego)
{
if (!nego)
return NEGO_STATE_FAIL;
return nego->state;
}
BOOL nego_set_state(rdpNego* nego, NEGO_STATE state)
{
if (!nego)
return FALSE;
nego->state = state;
return TRUE;
}
SEC_WINNT_AUTH_IDENTITY* nego_get_identity(rdpNego* nego)
{
rdpNla* nla;
if (!nego)
return NULL;
nla = transport_get_nla(nego->transport);
return nla_get_identity(nla);
}
void nego_free_nla(rdpNego* nego)
{
if (!nego || !nego->transport)
return;
transport_set_nla(nego->transport, NULL);
}
const BYTE* nego_get_routing_token(rdpNego* nego, DWORD* RoutingTokenLength)
{
if (!nego)
return NULL;
if (RoutingTokenLength)
*RoutingTokenLength = nego->RoutingTokenLength;
return nego->RoutingToken;
}
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