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FreeRDP/libfreerdp/core/connection.c

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/*
* FreeRDP: A Remote Desktop Protocol Implementation
* Connection Sequence
*
* Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.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 "info.h"
#include "input.h"
#include "rdp.h"
#include "connection.h"
#include "transport.h"
#include <winpr/crt.h>
#include <winpr/crypto.h>
#include <winpr/ssl.h>
#include <freerdp/log.h>
#include <freerdp/error.h>
#include <freerdp/listener.h>
#include <freerdp/cache/pointer.h>
#define TAG FREERDP_TAG("core.connection")
/**
* Connection Sequence
* client server
* | |
* |-----------------------X.224 Connection Request PDU--------------------->|
* |<----------------------X.224 Connection Confirm PDU----------------------|
* |-------MCS Connect-Initial PDU with GCC Conference Create Request------->|
* |<-----MCS Connect-Response PDU with GCC Conference Create Response-------|
* |------------------------MCS Erect Domain Request PDU-------------------->|
* |------------------------MCS Attach User Request PDU--------------------->|
* |<-----------------------MCS Attach User Confirm PDU----------------------|
* |------------------------MCS Channel Join Request PDU-------------------->|
* |<-----------------------MCS Channel Join Confirm PDU---------------------|
* |----------------------------Security Exchange PDU----------------------->|
* |-------------------------------Client Info PDU-------------------------->|
* |<---------------------License Error PDU - Valid Client-------------------|
* |<-----------------------------Demand Active PDU--------------------------|
* |------------------------------Confirm Active PDU------------------------>|
* |-------------------------------Synchronize PDU-------------------------->|
* |---------------------------Control PDU - Cooperate---------------------->|
* |------------------------Control PDU - Request Control------------------->|
* |--------------------------Persistent Key List PDU(s)-------------------->|
* |--------------------------------Font List PDU--------------------------->|
* |<------------------------------Synchronize PDU---------------------------|
* |<--------------------------Control PDU - Cooperate-----------------------|
* |<-----------------------Control PDU - Granted Control--------------------|
* |<-------------------------------Font Map PDU-----------------------------|
*
*/
/**
*
* Connection Sequence
*
* 1. Connection Initiation: The client initiates the connection by sending the server a
* Class 0 X.224 Connection Request PDU (section 2.2.1.1). The server responds with a
* Class 0 X.224 Connection Confirm PDU (section 2.2.1.2). From this point, all subsequent
* data sent between client and server is wrapped in an X.224 Data Protocol Data Unit (PDU).
*
* 2. Basic Settings Exchange: Basic settings are exchanged between the client and server by
* using the MCS Connect Initial PDU (section 2.2.1.3) and MCS Connect Response PDU (section 2.2.1.4).
* The Connect Initial PDU contains a Generic Conference Control (GCC) Conference Create Request,
* while the Connect Response PDU contains a GCC Conference Create Response. These two GCC packets
* contain concatenated blocks of settings data (such as core data, security data, and network data)
* which are read by client and server.
*
* 3. Channel Connection: The client sends an MCS Erect Domain Request PDU (section 2.2.1.5),
* followed by an MCS Attach User Request PDU (section 2.2.1.6) to attach the primary user identity
* to the MCS domain. The server responds with an MCS Attach User Confirm PDU (section 2.2.1.7)
* containing the User Channel ID. The client then proceeds to join the user channel, the
* input/output (I/O) channel, and all of the static virtual channels (the I/O and static virtual
* channel IDs are obtained from the data embedded in the GCC packets) by using multiple MCS Channel
* Join Request PDUs (section 2.2.1.8). The server confirms each channel with an MCS Channel Join
* Confirm PDU (section 2.2.1.9). (The client only sends a Channel Join Request after it has received
* the Channel Join Confirm for the previously sent request.)
*
* From this point, all subsequent data sent from the client to the server is wrapped in an MCS Send
* Data Request PDU, while data sent from the server to the client is wrapped in an MCS Send Data
* Indication PDU. This is in addition to the data being wrapped by an X.224 Data PDU.
*
* 4. RDP Security Commencement: If Standard RDP Security mechanisms (section 5.3) are being employed and
* encryption is in force (this is determined by examining the data embedded in the GCC Conference Create
* Response packet) then the client sends a Security Exchange PDU (section 2.2.1.10) containing an encrypted
* 32-byte random number to the server. This random number is encrypted with the public key of the server
* as described in section 5.3.4.1 (the server's public key, as well as a 32-byte server-generated random
* number, are both obtained from the data embedded in the GCC Conference Create Response packet). The client
* and server then utilize the two 32-byte random numbers to generate session keys which are used to encrypt
* and validate the integrity of subsequent RDP traffic.
*
* From this point, all subsequent RDP traffic can be encrypted and a security header is included with the
* data if encryption is in force. (The Client Info PDU (section 2.2.1.11) and licensing PDUs ([MS-RDPELE]
* section 2.2.2) are an exception in that they always have a security header). The Security Header follows
* the X.224 and MCS Headers and indicates whether the attached data is encrypted. Even if encryption is in
* force, server-to-client traffic may not always be encrypted, while client-to-server traffic must always be
* encrypted (encryption of licensing PDUs is optional, however).
*
* 5. Secure Settings Exchange: Secure client data (such as the username, password, and auto-reconnect cookie)
* is sent to the server by using the Client Info PDU (section 2.2.1.11).
*
* 6. Optional Connect-Time Auto-Detection: During the optional connect-time auto-detect phase the goal is to
* determine characteristics of the network, such as the round-trip latency time and the bandwidth of the link
* between the server and client. This is accomplished by exchanging a collection of PDUs (specified in section 2.2.1.4)
* over a predetermined period of time with enough data to ensure that the results are statistically relevant.
*
* 7. Licensing: The goal of the licensing exchange is to transfer a license from the server to the client.
* The client stores this license and on subsequent connections sends the license to the server for validation.
* However, in some situations the client may not be issued a license to store. In effect, the packets exchanged
* during this phase of the protocol depend on the licensing mechanisms employed by the server. Within the context
* of this document, it is assumed that the client will not be issued a license to store. For details regarding
* more advanced licensing scenarios that take place during the Licensing Phase, see [MS-RDPELE] section 1.3.
*
* 8. Optional Multitransport Bootstrapping: After the connection has been secured and the Licensing Phase has run
* to completion, the server can choose to initiate multitransport connections ([MS-RDPEMT] section 1.3).
* The Initiate Multitransport Request PDU (section 2.2.15.1) is sent by the server to the client and results
* in the out-of-band creation of a multitransport connection using messages from the RDP-UDP, TLS, DTLS, and
* multitransport protocols ([MS-RDPEMT] section 1.3.1).
*
* 9. Capabilities Exchange: The server sends the set of capabilities it supports to the client in a Demand Active PDU
* (section 2.2.1.13.1). The client responds with its capabilities by sending a Confirm Active PDU (section 2.2.1.13.2).
*
* 10. Connection Finalization: The client and server exchange PDUs to finalize the connection details. The client-to-server
* PDUs sent during this phase have no dependencies on any of the server-to-client PDUs; they may be sent as a single batch,
* provided that sequencing is maintained.
*
* - The Client Synchronize PDU (section 2.2.1.14) is sent after transmitting the Confirm Active PDU.
* - The Client Control (Cooperate) PDU (section 2.2.1.15) is sent after transmitting the Client Synchronize PDU.
* - The Client Control (Request Control) PDU (section 2.2.1.16) is sent after transmitting the Client Control (Cooperate) PDU.
* - The optional Persistent Key List PDUs (section 2.2.1.17) are sent after transmitting the Client Control (Request Control) PDU.
* - The Font List PDU (section 2.2.1.18) is sent after transmitting the Persistent Key List PDUs or, if the Persistent Key List
* PDUs were not sent, it is sent after transmitting the Client Control (Request Control) PDU (section 2.2.1.16).
*
* The server-to-client PDUs sent during the Connection Finalization Phase have dependencies on the client-to-server PDUs.
*
* - The optional Monitor Layout PDU (section 2.2.12.1) has no dependency on any client-to-server PDUs and is sent after the Demand Active PDU.
* - The Server Synchronize PDU (section 2.2.1.19) is sent in response to the Confirm Active PDU.
* - The Server Control (Cooperate) PDU (section 2.2.1.20) is sent after transmitting the Server Synchronize PDU.
* - The Server Control (Granted Control) PDU (section 2.2.1.21) is sent in response to the Client Control (Request Control) PDU.
* - The Font Map PDU (section 2.2.1.22) is sent in response to the Font List PDU.
*
* Once the client has sent the Confirm Active PDU, it can start sending mouse and keyboard input to the server, and upon receipt
* of the Font List PDU the server can start sending graphics output to the client.
*
* Besides input and graphics data, other data that can be exchanged between client and server after the connection has been
* finalized includes connection management information and virtual channel messages (exchanged between client-side plug-ins
* and server-side applications).
*/
static int rdp_client_connect_finalize(rdpRdp* rdp);
static BOOL rdp_client_reset_codecs(rdpContext* context)
{
rdpSettings* settings;
if (!context || !context->settings)
return FALSE;
settings = context->settings;
context->codecs = codecs_new(context);
if (!context->codecs)
return FALSE;
return freerdp_client_codecs_prepare(context->codecs, FREERDP_CODEC_ALL,
settings->DesktopWidth, settings->DesktopHeight);
}
/**
* Establish RDP Connection based on the settings given in the 'rdp' parameter.
* @msdn{cc240452}
* @param rdp RDP module
* @return true if the connection succeeded. FALSE otherwise.
*/
BOOL rdp_client_connect(rdpRdp* rdp)
{
UINT32 SelectedProtocol;
BOOL status;
rdpSettings* settings = rdp->settings;
/* make sure SSL is initialize for earlier enough for crypto, by taking advantage of winpr SSL FIPS flag for openssl initialization */
DWORD flags = WINPR_SSL_INIT_DEFAULT;
if (!rdp_client_reset_codecs(rdp->context))
return FALSE;
if (settings->FIPSMode)
flags |= WINPR_SSL_INIT_ENABLE_FIPS;
winpr_InitializeSSL(flags);
/* FIPS Mode forces the following and overrides the following(by happening later */
/* in the command line processing): */
/* 1. Disables NLA Security since NLA in freerdp uses NTLM(no Kerberos support yet) which uses algorithms */
/* not allowed in FIPS for sensitive data. So, we disallow NLA when FIPS is required. */
/* 2. Forces the only supported RDP encryption method to be FIPS. */
if (settings->FIPSMode || winpr_FIPSMode())
{
settings->NlaSecurity = FALSE;
settings->EncryptionMethods = ENCRYPTION_METHOD_FIPS;
}
nego_init(rdp->nego);
nego_set_target(rdp->nego, settings->ServerHostname, settings->ServerPort);
if (settings->GatewayEnabled)
{
char* user = NULL;
char* domain = NULL;
char* cookie = NULL;
int user_length = 0;
int domain_length = 0;
int cookie_length = 0;
if (settings->Username)
{
user = settings->Username;
user_length = strlen(settings->Username);
}
if (settings->Domain)
domain = settings->Domain;
else
domain = settings->ComputerName;
domain_length = strlen(domain);
cookie_length = domain_length + 1 + user_length;
cookie = (char*) malloc(cookie_length + 1);
if (!cookie)
return FALSE;
CopyMemory(cookie, domain, domain_length);
CharUpperBuffA(cookie, domain_length);
cookie[domain_length] = '\\';
if (settings->Username)
CopyMemory(&cookie[domain_length + 1], user, user_length);
cookie[cookie_length] = '\0';
status = nego_set_cookie(rdp->nego, cookie);
free(cookie);
}
else
{
status = nego_set_cookie(rdp->nego, settings->Username);
}
if (!status)
return FALSE;
nego_set_send_preconnection_pdu(rdp->nego, settings->SendPreconnectionPdu);
nego_set_preconnection_id(rdp->nego, settings->PreconnectionId);
nego_set_preconnection_blob(rdp->nego, settings->PreconnectionBlob);
nego_set_negotiation_enabled(rdp->nego, settings->NegotiateSecurityLayer);
nego_set_restricted_admin_mode_required(rdp->nego, settings->RestrictedAdminModeRequired);
nego_set_gateway_enabled(rdp->nego, settings->GatewayEnabled);
nego_set_gateway_bypass_local(rdp->nego, settings->GatewayBypassLocal);
nego_enable_rdp(rdp->nego, settings->RdpSecurity);
nego_enable_tls(rdp->nego, settings->TlsSecurity);
nego_enable_nla(rdp->nego, settings->NlaSecurity);
nego_enable_ext(rdp->nego, settings->ExtSecurity);
if (settings->MstscCookieMode)
settings->CookieMaxLength = MSTSC_COOKIE_MAX_LENGTH;
nego_set_cookie_max_length(rdp->nego, settings->CookieMaxLength);
if (settings->LoadBalanceInfo && (settings->LoadBalanceInfoLength > 0))
{
if (!nego_set_routing_token(rdp->nego, settings->LoadBalanceInfo, settings->LoadBalanceInfoLength))
return FALSE;
}
rdp_client_transition_to_state(rdp, CONNECTION_STATE_NEGO);
if (!nego_connect(rdp->nego))
{
if (!freerdp_get_last_error(rdp->context))
{
freerdp_set_last_error(rdp->context, FREERDP_ERROR_SECURITY_NEGO_CONNECT_FAILED);
WLog_ERR(TAG, "Error: protocol security negotiation or connection failure");
}
return FALSE;
}
SelectedProtocol = nego_get_selected_protocol(rdp->nego);
if ((SelectedProtocol & PROTOCOL_SSL) || (SelectedProtocol == PROTOCOL_RDP))
{
if ((settings->Username != NULL) && ((settings->Password != NULL) ||
(settings->RedirectionPassword != NULL && settings->RedirectionPasswordLength > 0)))
settings->AutoLogonEnabled = TRUE;
}
/* everything beyond this point is event-driven and non blocking */
rdp->transport->ReceiveCallback = rdp_recv_callback;
rdp->transport->ReceiveExtra = rdp;
transport_set_blocking_mode(rdp->transport, FALSE);
if (rdp->state != CONNECTION_STATE_NLA)
{
if (!mcs_client_begin(rdp->mcs))
return FALSE;
}
while (rdp->state != CONNECTION_STATE_ACTIVE)
{
if (rdp_check_fds(rdp) < 0)
{
if (!freerdp_get_last_error(rdp->context))
freerdp_set_last_error(rdp->context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED);
return FALSE;
}
SwitchToThread();
}
return TRUE;
}
BOOL rdp_client_disconnect(rdpRdp* rdp)
{
rdpContext* context;
if (!rdp || !rdp->settings || !rdp->context)
return FALSE;
context = rdp->context;
if (!nego_disconnect(rdp->nego))
return FALSE;
rdp_reset(rdp);
rdp_client_transition_to_state(rdp, CONNECTION_STATE_INITIAL);
if (freerdp_channels_disconnect(context->channels, context->instance) != CHANNEL_RC_OK)
return FALSE;
codecs_free(context->codecs);
return TRUE;
}
BOOL rdp_client_disconnect_and_clear(rdpRdp* rdp)
{
rdpContext* context;
if (!rdp_client_disconnect(rdp))
return FALSE;
context = rdp->context;
context->LastError = FREERDP_ERROR_SUCCESS;
clearChannelError(context);
ResetEvent(context->abortEvent);
return TRUE;
}
static BOOL rdp_client_reconnect_channels(rdpRdp* rdp, BOOL redirect)
{
BOOL status = FALSE;
rdpContext* context;
if (!rdp || !rdp->context || !rdp->context->channels)
return FALSE;
context = rdp->context;
if (context->instance->ConnectionCallbackState == CLIENT_STATE_INITIAL)
return FALSE;
if (context->instance->ConnectionCallbackState == CLIENT_STATE_PRECONNECT_PASSED)
{
if (redirect)
return TRUE;
pointer_cache_register_callbacks(context->update);
if (!IFCALLRESULT(FALSE, context->instance->PostConnect, context->instance))
return FALSE;
context->instance->ConnectionCallbackState = CLIENT_STATE_POSTCONNECT_PASSED;
}
if (context->instance->ConnectionCallbackState == CLIENT_STATE_POSTCONNECT_PASSED)
status = (freerdp_channels_post_connect(context->channels, context->instance) == CHANNEL_RC_OK);
return status;
}
static BOOL rdp_client_redirect_resolvable(const char* host)
{
struct addrinfo* result = freerdp_tcp_resolve_host(host, -1, 0);
if (!result)
return FALSE;
freeaddrinfo(result);
return TRUE;
}
static BOOL rdp_client_redirect_try_fqdn(rdpSettings* settings)
{
if (settings->RedirectionFlags & LB_TARGET_FQDN)
{
if (settings->GatewayEnabled || rdp_client_redirect_resolvable(settings->RedirectionTargetFQDN))
{
free(settings->ServerHostname);
settings->ServerHostname = _strdup(settings->RedirectionTargetFQDN);
if (!settings->ServerHostname)
return FALSE;
return TRUE;
}
}
return FALSE;
}
static BOOL rdp_client_redirect_try_ip(rdpSettings* settings)
{
if (settings->RedirectionFlags & LB_TARGET_NET_ADDRESS)
{
free(settings->ServerHostname);
settings->ServerHostname = _strdup(settings->TargetNetAddress);
if (!settings->ServerHostname)
return FALSE;
return TRUE;
}
return FALSE;
}
static BOOL rdp_client_redirect_try_netbios(rdpSettings* settings)
{
if (settings->RedirectionFlags & LB_TARGET_NETBIOS_NAME)
{
if (settings->GatewayEnabled || rdp_client_redirect_resolvable(settings->RedirectionTargetNetBiosName))
{
free(settings->ServerHostname);
settings->ServerHostname = _strdup(settings->RedirectionTargetNetBiosName);
if (!settings->ServerHostname)
return FALSE;
return TRUE;
}
}
return FALSE;
}
BOOL rdp_client_redirect(rdpRdp* rdp)
{
BOOL status;
rdpSettings* settings;
if (!rdp || !rdp->settings)
return FALSE;
settings = rdp->settings;
if (!rdp_client_disconnect_and_clear(rdp))
return FALSE;
if (rdp_redirection_apply_settings(rdp) != 0)
return FALSE;
if (settings->RedirectionFlags & LB_LOAD_BALANCE_INFO)
{
if (settings->LoadBalanceInfo && (settings->LoadBalanceInfoLength > 0))
{
if (!nego_set_routing_token(rdp->nego, settings->LoadBalanceInfo, settings->LoadBalanceInfoLength))
return FALSE;
}
}
else
{
BOOL haveRedirectAddress = FALSE;
UINT32 redirectionMask = settings->RedirectionPreferType;
do
{
const BOOL tryFQDN = (redirectionMask & 0x01) == 0;
const BOOL tryNetAddress = (redirectionMask & 0x02) == 0;
const BOOL tryNetbios = (redirectionMask & 0x04) == 0;
if (tryFQDN && !haveRedirectAddress)
haveRedirectAddress = rdp_client_redirect_try_fqdn(settings);
if (tryNetAddress && !haveRedirectAddress)
haveRedirectAddress = rdp_client_redirect_try_ip(settings);
if (tryNetbios && !haveRedirectAddress)
haveRedirectAddress = rdp_client_redirect_try_netbios(settings);
redirectionMask >>= 3;
}
while (!haveRedirectAddress && (redirectionMask != 0));
}
if (settings->RedirectionFlags & LB_USERNAME)
{
free(settings->Username);
settings->Username = _strdup(settings->RedirectionUsername);
if (!settings->Username)
return FALSE;
}
if (settings->RedirectionFlags & LB_DOMAIN)
{
free(settings->Domain);
settings->Domain = _strdup(settings->RedirectionDomain);
if (!settings->Domain)
return FALSE;
}
status = rdp_client_connect(rdp);
if (status)
status = rdp_client_reconnect_channels(rdp, TRUE);
return status;
}
BOOL rdp_client_reconnect(rdpRdp* rdp)
{
BOOL status;
if (!rdp || !rdp->context || !rdp->context->channels)
return FALSE;
if (!rdp_client_disconnect_and_clear(rdp))
return FALSE;
status = rdp_client_connect(rdp);
if (status)
status = rdp_client_reconnect_channels(rdp, FALSE);
return status;
}
static const BYTE fips_ivec[8] = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
static BOOL rdp_client_establish_keys(rdpRdp* rdp)
{
BYTE* mod;
BYTE* exp;
wStream* s;
UINT32 length;
UINT32 key_len;
int status = 0;
BOOL ret = FALSE;
rdpSettings* settings;
BYTE* crypt_client_random = NULL;
settings = rdp->settings;
if (!settings->UseRdpSecurityLayer)
{
/* no RDP encryption */
return TRUE;
}
/* encrypt client random */
free(settings->ClientRandom);
settings->ClientRandomLength = CLIENT_RANDOM_LENGTH;
settings->ClientRandom = malloc(settings->ClientRandomLength);
if (!settings->ClientRandom)
return FALSE;
winpr_RAND(settings->ClientRandom, settings->ClientRandomLength);
key_len = settings->RdpServerCertificate->cert_info.ModulusLength;
mod = settings->RdpServerCertificate->cert_info.Modulus;
exp = settings->RdpServerCertificate->cert_info.exponent;
/*
* client random must be (bitlen / 8) + 8 - see [MS-RDPBCGR] 5.3.4.1
* for details
*/
crypt_client_random = calloc(key_len + 8, 1);
if (!crypt_client_random)
return FALSE;
crypto_rsa_public_encrypt(settings->ClientRandom, settings->ClientRandomLength, key_len, mod, exp,
crypt_client_random);
/* send crypt client random to server */
length = RDP_PACKET_HEADER_MAX_LENGTH + RDP_SECURITY_HEADER_LENGTH + 4 + key_len + 8;
s = Stream_New(NULL, length);
if (!s)
{
WLog_ERR(TAG, "Stream_New failed!");
goto end;
}
rdp_write_header(rdp, s, length, MCS_GLOBAL_CHANNEL_ID);
rdp_write_security_header(s, SEC_EXCHANGE_PKT | SEC_LICENSE_ENCRYPT_SC);
length = key_len + 8;
Stream_Write_UINT32(s, length);
Stream_Write(s, crypt_client_random, length);
Stream_SealLength(s);
status = transport_write(rdp->mcs->transport, s);
Stream_Free(s, TRUE);
if (status < 0)
goto end;
rdp->do_crypt_license = TRUE;
/* now calculate encrypt / decrypt and update keys */
if (!security_establish_keys(settings->ClientRandom, rdp))
goto end;
rdp->do_crypt = TRUE;
if (settings->SaltedChecksum)
rdp->do_secure_checksum = TRUE;
if (settings->EncryptionMethods == ENCRYPTION_METHOD_FIPS)
{
rdp->fips_encrypt = winpr_Cipher_New(WINPR_CIPHER_DES_EDE3_CBC,
WINPR_ENCRYPT,
rdp->fips_encrypt_key,
fips_ivec);
if (!rdp->fips_encrypt)
{
WLog_ERR(TAG, "unable to allocate des3 encrypt key");
goto end;
}
rdp->fips_decrypt = winpr_Cipher_New(WINPR_CIPHER_DES_EDE3_CBC,
WINPR_DECRYPT,
rdp->fips_decrypt_key,
fips_ivec);
if (!rdp->fips_decrypt)
{
WLog_ERR(TAG, "unable to allocate des3 decrypt key");
goto end;
}
ret = TRUE;
goto end;
}
rdp->rc4_decrypt_key = winpr_RC4_New(rdp->decrypt_key, rdp->rc4_key_len);
rdp->rc4_encrypt_key = winpr_RC4_New(rdp->encrypt_key, rdp->rc4_key_len);
if (!rdp->rc4_decrypt_key || !rdp->rc4_encrypt_key)
goto end;
ret = TRUE;
end:
free(crypt_client_random);
if (!ret)
{
winpr_Cipher_Free(rdp->fips_decrypt);
winpr_Cipher_Free(rdp->fips_encrypt);
winpr_RC4_Free(rdp->rc4_decrypt_key);
winpr_RC4_Free(rdp->rc4_encrypt_key);
rdp->fips_decrypt = NULL;
rdp->fips_encrypt = NULL;
rdp->rc4_decrypt_key = NULL;
rdp->rc4_encrypt_key = NULL;
}
return ret;
}
BOOL rdp_server_establish_keys(rdpRdp* rdp, wStream* s)
{
BYTE* client_random = NULL;
BYTE* crypt_client_random = NULL;
UINT32 rand_len, key_len;
UINT16 channel_id, length, sec_flags;
BYTE* mod;
BYTE* priv_exp;
BOOL ret = FALSE;
if (!rdp->settings->UseRdpSecurityLayer)
{
/* No RDP Security. */
return TRUE;
}
if (!rdp_read_header(rdp, s, &length, &channel_id))
{
WLog_ERR(TAG, "invalid RDP header");
return FALSE;
}
if (!rdp_read_security_header(s, &sec_flags, NULL))
{
WLog_ERR(TAG, "invalid security header");
return FALSE;
}
if ((sec_flags & SEC_EXCHANGE_PKT) == 0)
{
WLog_ERR(TAG, "missing SEC_EXCHANGE_PKT in security header");
return FALSE;
}
rdp->do_crypt_license = (sec_flags & SEC_LICENSE_ENCRYPT_SC) != 0 ? TRUE : FALSE;
if (Stream_GetRemainingLength(s) < 4)
return FALSE;
Stream_Read_UINT32(s, rand_len);
/* rand_len already includes 8 bytes of padding */
if (Stream_GetRemainingLength(s) < rand_len)
return FALSE;
key_len = rdp->settings->RdpServerRsaKey->ModulusLength;
client_random = malloc(key_len);
if (!client_random)
return FALSE;
if (rand_len != key_len + 8)
{
WLog_ERR(TAG, "invalid encrypted client random length");
free(client_random);
goto end;
}
crypt_client_random = calloc(1, rand_len);
if (!crypt_client_random)
{
free(client_random);
goto end;
}
Stream_Read(s, crypt_client_random, rand_len);
mod = rdp->settings->RdpServerRsaKey->Modulus;
priv_exp = rdp->settings->RdpServerRsaKey->PrivateExponent;
if (crypto_rsa_private_decrypt(crypt_client_random, rand_len - 8, key_len, mod, priv_exp,
client_random) <= 0)
{
free(client_random);
goto end;
}
rdp->settings->ClientRandom = client_random;
rdp->settings->ClientRandomLength = 32;
/* now calculate encrypt / decrypt and update keys */
if (!security_establish_keys(client_random, rdp))
goto end;
rdp->do_crypt = TRUE;
if (rdp->settings->EncryptionMethods == ENCRYPTION_METHOD_FIPS)
{
rdp->fips_encrypt = winpr_Cipher_New(WINPR_CIPHER_DES_EDE3_CBC,
WINPR_ENCRYPT,
rdp->fips_encrypt_key,
fips_ivec);
if (!rdp->fips_encrypt)
{
WLog_ERR(TAG, "unable to allocate des3 encrypt key");
goto end;
}
rdp->fips_decrypt = winpr_Cipher_New(WINPR_CIPHER_DES_EDE3_CBC,
WINPR_DECRYPT,
rdp->fips_decrypt_key,
fips_ivec);
if (!rdp->fips_decrypt)
{
WLog_ERR(TAG, "unable to allocate des3 decrypt key");
goto end;
}
ret = TRUE;
goto end;
}
rdp->rc4_decrypt_key = winpr_RC4_New(rdp->decrypt_key, rdp->rc4_key_len);
rdp->rc4_encrypt_key = winpr_RC4_New(rdp->encrypt_key, rdp->rc4_key_len);
if (!rdp->rc4_decrypt_key || !rdp->rc4_encrypt_key)
goto end;
ret = TRUE;
end:
free(crypt_client_random);
if (!ret)
{
winpr_Cipher_Free(rdp->fips_encrypt);
winpr_Cipher_Free(rdp->fips_decrypt);
winpr_RC4_Free(rdp->rc4_encrypt_key);
winpr_RC4_Free(rdp->rc4_decrypt_key);
rdp->fips_encrypt = NULL;
rdp->fips_decrypt = NULL;
rdp->rc4_encrypt_key = NULL;
rdp->rc4_decrypt_key = NULL;
}
return ret;
}
BOOL rdp_client_connect_mcs_channel_join_confirm(rdpRdp* rdp, wStream* s)
{
UINT32 i;
UINT16 channelId;
BOOL allJoined = TRUE;
rdpMcs* mcs = rdp->mcs;
if (!mcs_recv_channel_join_confirm(mcs, s, &channelId))
return FALSE;
if (!mcs->userChannelJoined)
{
if (channelId != mcs->userId)
return FALSE;
mcs->userChannelJoined = TRUE;
if (!mcs_send_channel_join_request(mcs, MCS_GLOBAL_CHANNEL_ID))
return FALSE;
}
else if (!mcs->globalChannelJoined)
{
if (channelId != MCS_GLOBAL_CHANNEL_ID)
return FALSE;
mcs->globalChannelJoined = TRUE;
if (mcs->messageChannelId != 0)
{
if (!mcs_send_channel_join_request(mcs, mcs->messageChannelId))
return FALSE;
allJoined = FALSE;
}
else
{
if (mcs->channelCount > 0)
{
if (!mcs_send_channel_join_request(mcs, mcs->channels[0].ChannelId))
return FALSE;
allJoined = FALSE;
}
}
}
else if ((mcs->messageChannelId != 0) && !mcs->messageChannelJoined)
{
if (channelId != mcs->messageChannelId)
return FALSE;
mcs->messageChannelJoined = TRUE;
if (mcs->channelCount > 0)
{
if (!mcs_send_channel_join_request(mcs, mcs->channels[0].ChannelId))
return FALSE;
allJoined = FALSE;
}
}
else
{
for (i = 0; i < mcs->channelCount; i++)
{
if (mcs->channels[i].joined)
continue;
if (mcs->channels[i].ChannelId != channelId)
return FALSE;
mcs->channels[i].joined = TRUE;
break;
}
if (i + 1 < mcs->channelCount)
{
if (!mcs_send_channel_join_request(mcs, mcs->channels[i + 1].ChannelId))
return FALSE;
allJoined = FALSE;
}
}
if (mcs->userChannelJoined && mcs->globalChannelJoined && allJoined)
{
if (!rdp_client_establish_keys(rdp))
return FALSE;
if (!rdp_send_client_info(rdp))
return FALSE;
rdp_client_transition_to_state(rdp, CONNECTION_STATE_LICENSING);
}
return TRUE;
}
BOOL rdp_client_connect_auto_detect(rdpRdp* rdp, wStream* s)
{
BYTE* mark;
UINT16 length;
UINT16 channelId;
/* If the MCS message channel has been joined... */
if (rdp->mcs->messageChannelId != 0)
{
/* Process any MCS message channel PDUs. */
Stream_GetPointer(s, mark);
if (rdp_read_header(rdp, s, &length, &channelId))
{
if (channelId == rdp->mcs->messageChannelId)
{
UINT16 securityFlags = 0;
if (!rdp_read_security_header(s, &securityFlags, &length))
return FALSE;
if (securityFlags & SEC_ENCRYPT)
{
if (!rdp_decrypt(rdp, s, length, securityFlags))
{
WLog_ERR(TAG, "rdp_decrypt failed");
return FALSE;
}
}
if (rdp_recv_message_channel_pdu(rdp, s, securityFlags) == 0)
return TRUE;
}
}
Stream_SetPointer(s, mark);
}
return FALSE;
}
int rdp_client_connect_license(rdpRdp* rdp, wStream* s)
{
int status;
status = license_recv(rdp->license, s);
if (status < 0)
return status;
if (rdp->license->state == LICENSE_STATE_ABORTED)
{
WLog_ERR(TAG, "license connection sequence aborted.");
return -1;
}
if (rdp->license->state == LICENSE_STATE_COMPLETED)
{
rdp_client_transition_to_state(rdp, CONNECTION_STATE_CAPABILITIES_EXCHANGE);
}
return 0;
}
int rdp_client_connect_demand_active(rdpRdp* rdp, wStream* s)
{
BYTE* mark;
UINT16 width;
UINT16 height;
width = rdp->settings->DesktopWidth;
height = rdp->settings->DesktopHeight;
Stream_GetPointer(s, mark);
if (!rdp_recv_demand_active(rdp, s))
{
UINT16 channelId;
Stream_SetPointer(s, mark);
rdp_recv_get_active_header(rdp, s, &channelId);
/* Was Stream_Seek(s, RDP_PACKET_HEADER_MAX_LENGTH);
* but the headers aren't always that length,
* so that could result in a bad offset.
*/
return rdp_recv_out_of_sequence_pdu(rdp, s);
}
if (freerdp_shall_disconnect(rdp->instance))
return 0;
if (!rdp_send_confirm_active(rdp))
return -1;
if (!input_register_client_callbacks(rdp->input))
{
WLog_ERR(TAG, "error registering client callbacks");
return -1;
}
/**
* The server may request a different desktop size during Deactivation-Reactivation sequence.
* In this case, the UI should be informed and do actual window resizing at this point.
*/
if (width != rdp->settings->DesktopWidth || height != rdp->settings->DesktopHeight)
{
BOOL status = TRUE;
IFCALLRET(rdp->update->DesktopResize, status, rdp->update->context);
if (!status)
{
WLog_ERR(TAG, "client desktop resize callback failed");
return -1;
}
}
rdp_client_transition_to_state(rdp, CONNECTION_STATE_FINALIZATION);
return rdp_client_connect_finalize(rdp);
}
int rdp_client_connect_finalize(rdpRdp* rdp)
{
/**
* [MS-RDPBCGR] 1.3.1.1 - 8.
* The client-to-server PDUs sent during this phase have no dependencies on any of the server-to-
* client PDUs; they may be sent as a single batch, provided that sequencing is maintained.
*/
if (!rdp_send_client_synchronize_pdu(rdp))
return -1;
if (!rdp_send_client_control_pdu(rdp, CTRLACTION_COOPERATE))
return -1;
if (!rdp_send_client_control_pdu(rdp, CTRLACTION_REQUEST_CONTROL))
return -1;
/**
* [MS-RDPBCGR] 2.2.1.17
* Client persistent key list must be sent if a bitmap is
* stored in persistent bitmap cache or the server has advertised support for bitmap
* host cache and a deactivation reactivation sequence is *not* in progress.
*/
if (!rdp->deactivation_reactivation && rdp->settings->BitmapCachePersistEnabled)
{
if (!rdp_send_client_persistent_key_list_pdu(rdp))
return -1;
}
if (!rdp_send_client_font_list_pdu(rdp, FONTLIST_FIRST | FONTLIST_LAST))
return -1;
return 0;
}
int rdp_client_transition_to_state(rdpRdp* rdp, int state)
{
int status = 0;
switch (state)
{
case CONNECTION_STATE_INITIAL:
rdp->state = CONNECTION_STATE_INITIAL;
break;
case CONNECTION_STATE_NEGO:
rdp->state = CONNECTION_STATE_NEGO;
break;
case CONNECTION_STATE_NLA:
rdp->state = CONNECTION_STATE_NLA;
break;
case CONNECTION_STATE_MCS_CONNECT:
rdp->state = CONNECTION_STATE_MCS_CONNECT;
break;
case CONNECTION_STATE_MCS_ERECT_DOMAIN:
rdp->state = CONNECTION_STATE_MCS_ERECT_DOMAIN;
break;
case CONNECTION_STATE_MCS_ATTACH_USER:
rdp->state = CONNECTION_STATE_MCS_ATTACH_USER;
break;
case CONNECTION_STATE_MCS_CHANNEL_JOIN:
rdp->state = CONNECTION_STATE_MCS_CHANNEL_JOIN;
break;
case CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT:
rdp->state = CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT;
break;
case CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE:
rdp->state = CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE;
break;
case CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT:
rdp->state = CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT;
break;
case CONNECTION_STATE_LICENSING:
rdp->state = CONNECTION_STATE_LICENSING;
break;
case CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING:
rdp->state = CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING;
break;
case CONNECTION_STATE_CAPABILITIES_EXCHANGE:
rdp->state = CONNECTION_STATE_CAPABILITIES_EXCHANGE;
break;
case CONNECTION_STATE_FINALIZATION:
rdp->state = CONNECTION_STATE_FINALIZATION;
update_reset_state(rdp->update);
rdp->finalize_sc_pdus = 0;
break;
case CONNECTION_STATE_ACTIVE:
rdp->state = CONNECTION_STATE_ACTIVE;
break;
default:
status = -1;
break;
}
return status;
}
BOOL rdp_server_accept_nego(rdpRdp* rdp, wStream* s)
{
UINT32 SelectedProtocol = 0;
UINT32 RequestedProtocols;
BOOL status;
rdpSettings* settings = rdp->settings;
rdpNego* nego = rdp->nego;
transport_set_blocking_mode(rdp->transport, TRUE);
if (!nego_read_request(nego, s))
return FALSE;
RequestedProtocols = nego_get_requested_protocols(nego);
WLog_INFO(TAG, "Client Security: NLA:%d TLS:%d RDP:%d",
(RequestedProtocols & PROTOCOL_HYBRID) ? 1 : 0,
(RequestedProtocols & PROTOCOL_SSL) ? 1 : 0,
(RequestedProtocols == PROTOCOL_RDP) ? 1 : 0
);
WLog_INFO(TAG, "Server Security: NLA:%"PRId32" TLS:%"PRId32" RDP:%"PRId32"",
settings->NlaSecurity, settings->TlsSecurity, settings->RdpSecurity);
if ((settings->NlaSecurity) && (RequestedProtocols & PROTOCOL_HYBRID))
{
SelectedProtocol = PROTOCOL_HYBRID;
}
else if ((settings->TlsSecurity) && (RequestedProtocols & PROTOCOL_SSL))
{
SelectedProtocol = PROTOCOL_SSL;
}
else if ((settings->RdpSecurity) && (RequestedProtocols == PROTOCOL_RDP))
{
SelectedProtocol = PROTOCOL_RDP;
}
else
{
/*
* when here client and server aren't compatible, we select the right
* error message to return to the client in the nego failure packet
*/
SelectedProtocol = PROTOCOL_FAILED_NEGO;
if (settings->RdpSecurity)
{
WLog_ERR(TAG, "server supports only Standard RDP Security");
SelectedProtocol |= SSL_NOT_ALLOWED_BY_SERVER;
}
else
{
if (settings->NlaSecurity && !settings->TlsSecurity)
{
WLog_WARN(TAG, "server supports only NLA Security");
SelectedProtocol |= HYBRID_REQUIRED_BY_SERVER;
}
else
{
WLog_WARN(TAG, "server supports only a SSL based Security (TLS or NLA)");
SelectedProtocol |= SSL_REQUIRED_BY_SERVER;
}
}
WLog_ERR(TAG, "Protocol security negotiation failure");
}
if (!(SelectedProtocol & PROTOCOL_FAILED_NEGO))
{
WLog_INFO(TAG, "Negotiated Security: NLA:%d TLS:%d RDP:%d",
(SelectedProtocol & PROTOCOL_HYBRID) ? 1 : 0,
(SelectedProtocol & PROTOCOL_SSL) ? 1 : 0,
(SelectedProtocol == PROTOCOL_RDP) ? 1 : 0
);
}
if (!nego_set_selected_protocol(nego, SelectedProtocol))
return FALSE;
if (!nego_send_negotiation_response(nego))
return FALSE;
SelectedProtocol = nego_get_selected_protocol(nego);
status = FALSE;
if (SelectedProtocol & PROTOCOL_HYBRID)
status = transport_accept_nla(rdp->transport);
else if (SelectedProtocol & PROTOCOL_SSL)
status = transport_accept_tls(rdp->transport);
else if (SelectedProtocol == PROTOCOL_RDP) /* 0 */
status = transport_accept_rdp(rdp->transport);
if (!status)
return FALSE;
transport_set_blocking_mode(rdp->transport, FALSE);
rdp_server_transition_to_state(rdp, CONNECTION_STATE_NEGO);
return TRUE;
}
BOOL rdp_server_accept_mcs_connect_initial(rdpRdp* rdp, wStream* s)
{
UINT32 i;
rdpMcs* mcs = rdp->mcs;
if (!mcs_recv_connect_initial(mcs, s))
return FALSE;
WLog_INFO(TAG, "Accepted client: %s", rdp->settings->ClientHostname);
WLog_INFO(TAG, "Accepted channels:");
for (i = 0; i < mcs->channelCount; i++)
{
WLog_INFO(TAG, " %s", mcs->channels[i].Name);
}
if (!mcs_send_connect_response(mcs))
return FALSE;
rdp_server_transition_to_state(rdp, CONNECTION_STATE_MCS_CONNECT);
return TRUE;
}
BOOL rdp_server_accept_mcs_erect_domain_request(rdpRdp* rdp, wStream* s)
{
if (!mcs_recv_erect_domain_request(rdp->mcs, s))
return FALSE;
rdp_server_transition_to_state(rdp, CONNECTION_STATE_MCS_ERECT_DOMAIN);
return TRUE;
}
BOOL rdp_server_accept_mcs_attach_user_request(rdpRdp* rdp, wStream* s)
{
if (!mcs_recv_attach_user_request(rdp->mcs, s))
return FALSE;
if (!mcs_send_attach_user_confirm(rdp->mcs))
return FALSE;
rdp_server_transition_to_state(rdp, CONNECTION_STATE_MCS_ATTACH_USER);
return TRUE;
}
BOOL rdp_server_accept_mcs_channel_join_request(rdpRdp* rdp, wStream* s)
{
UINT32 i;
UINT16 channelId;
BOOL allJoined = TRUE;
rdpMcs* mcs = rdp->mcs;
if (!mcs_recv_channel_join_request(mcs, s, &channelId))
return FALSE;
if (!mcs_send_channel_join_confirm(mcs, channelId))
return FALSE;
if (channelId == mcs->userId)
mcs->userChannelJoined = TRUE;
else if (channelId == MCS_GLOBAL_CHANNEL_ID)
mcs->globalChannelJoined = TRUE;
else if (channelId == mcs->messageChannelId)
mcs->messageChannelJoined = TRUE;
for (i = 0; i < mcs->channelCount; i++)
{
if (mcs->channels[i].ChannelId == channelId)
mcs->channels[i].joined = TRUE;
if (!mcs->channels[i].joined)
allJoined = FALSE;
}
if ((mcs->userChannelJoined) && (mcs->globalChannelJoined) && (mcs->messageChannelId == 0 ||
mcs->messageChannelJoined) && allJoined)
{
rdp_server_transition_to_state(rdp, CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT);
}
return TRUE;
}
BOOL rdp_server_accept_confirm_active(rdpRdp* rdp, wStream* s)
{
freerdp_peer* peer = rdp->context->peer;
if (rdp->state != CONNECTION_STATE_CAPABILITIES_EXCHANGE)
return FALSE;
if (!rdp_recv_confirm_active(rdp, s))
return FALSE;
if (peer->ClientCapabilities && !peer->ClientCapabilities(peer))
return FALSE;
if (rdp->settings->SaltedChecksum)
rdp->do_secure_checksum = TRUE;
rdp_server_transition_to_state(rdp, CONNECTION_STATE_FINALIZATION);
if (!rdp_send_server_synchronize_pdu(rdp))
return FALSE;
if (!rdp_send_server_control_cooperate_pdu(rdp))
return FALSE;
return TRUE;
}
BOOL rdp_server_reactivate(rdpRdp* rdp)
{
freerdp_peer* client = NULL;
if (rdp->context && rdp->context->peer)
client = rdp->context->peer;
if (client)
client->activated = FALSE;
if (!rdp_send_deactivate_all(rdp))
return FALSE;
rdp_server_transition_to_state(rdp, CONNECTION_STATE_CAPABILITIES_EXCHANGE);
if (!rdp_send_demand_active(rdp))
return FALSE;
rdp->AwaitCapabilities = TRUE;
return TRUE;
}
int rdp_server_transition_to_state(rdpRdp* rdp, int state)
{
int status = 0;
freerdp_peer* client = NULL;
if (rdp->state >= CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT)
client = rdp->context->peer;
if (rdp->state < CONNECTION_STATE_ACTIVE)
{
if (client)
client->activated = FALSE;
}
switch (state)
{
case CONNECTION_STATE_INITIAL:
rdp->state = CONNECTION_STATE_INITIAL;
break;
case CONNECTION_STATE_NEGO:
rdp->state = CONNECTION_STATE_NEGO;
break;
case CONNECTION_STATE_MCS_CONNECT:
rdp->state = CONNECTION_STATE_MCS_CONNECT;
break;
case CONNECTION_STATE_MCS_ERECT_DOMAIN:
rdp->state = CONNECTION_STATE_MCS_ERECT_DOMAIN;
break;
case CONNECTION_STATE_MCS_ATTACH_USER:
rdp->state = CONNECTION_STATE_MCS_ATTACH_USER;
break;
case CONNECTION_STATE_MCS_CHANNEL_JOIN:
rdp->state = CONNECTION_STATE_MCS_CHANNEL_JOIN;
break;
case CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT:
rdp->state = CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT;
break;
case CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE:
rdp->state = CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE;
break;
case CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT:
rdp->state = CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT;
break;
case CONNECTION_STATE_LICENSING:
rdp->state = CONNECTION_STATE_LICENSING;
break;
case CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING:
rdp->state = CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING;
break;
case CONNECTION_STATE_CAPABILITIES_EXCHANGE:
rdp->state = CONNECTION_STATE_CAPABILITIES_EXCHANGE;
rdp->AwaitCapabilities = FALSE;
break;
case CONNECTION_STATE_FINALIZATION:
rdp->state = CONNECTION_STATE_FINALIZATION;
rdp->finalize_sc_pdus = 0;
break;
case CONNECTION_STATE_ACTIVE:
rdp->state = CONNECTION_STATE_ACTIVE;
update_reset_state(rdp->update);
if (client)
{
if (!client->connected)
{
/**
* PostConnect should only be called once and should not
* be called after a reactivation sequence.
*/
IFCALLRET(client->PostConnect, client->connected, client);
if (!client->connected)
return -1;
}
if (rdp->state >= CONNECTION_STATE_ACTIVE)
{
IFCALLRET(client->Activate, client->activated, client);
if (!client->activated)
return -1;
}
}
break;
default:
status = -1;
break;
}
return status;
}
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