/* * FreeRDP: A Remote Desktop Protocol Implementation * Connection Sequence * * Copyright 2011 Marc-Andre Moreau * Copyright 2015 Thincast Technologies GmbH * Copyright 2015 DI (FH) Martin Haimberger * * 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 #include "info.h" #include "input.h" #include "rdp.h" #include "connection.h" #include "transport.h" #include #include #include #include #include #include #include #include "utils.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_set_state(rdpRdp* rdp, CONNECTION_STATE state); static BOOL rdp_client_reset_codecs(rdpContext* context) { rdpSettings* settings; if (!context || !context->settings) return FALSE; settings = context->settings; if (!freerdp_settings_get_bool(settings, FreeRDP_DeactivateClientDecoding)) { codecs_free(context->codecs); context->codecs = codecs_new(context); if (!context->codecs) return FALSE; if (!freerdp_client_codecs_prepare(context->codecs, freerdp_settings_get_codecs_flags(settings), settings->DesktopWidth, settings->DesktopHeight)) return FALSE; /* Runtime H264 detection. (only available if dynamic backend loading is defined) * If no backend is available disable it before the channel is loaded. */ #if defined(WITH_GFX_H264) && defined(WITH_OPENH264_LOADING) if (!context->codecs->h264) { settings->GfxH264 = FALSE; settings->GfxAVC444 = FALSE; settings->GfxAVC444v2 = FALSE; } #endif } return TRUE; } /** * 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; /* 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; UINT32 timeout; WINPR_ASSERT(rdp); settings = rdp->settings; WINPR_ASSERT(settings); 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; size_t user_length = 0; size_t domain_length = 0; size_t 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; } if (!freerdp_settings_get_bool(settings, FreeRDP_TransportDumpReplay)) { 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_log(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) && ((freerdp_settings_get_string(settings, FreeRDP_Password) != NULL) || (settings->RedirectionPassword != NULL && settings->RedirectionPasswordLength > 0))) settings->AutoLogonEnabled = TRUE; } transport_set_blocking_mode(rdp->transport, FALSE); } /* everything beyond this point is event-driven and non blocking */ transport_set_recv_callbacks(rdp->transport, rdp_recv_callback, rdp); if (rdp_get_state(rdp) != CONNECTION_STATE_NLA) { rdp_client_transition_to_state(rdp, CONNECTION_STATE_MCS_CONNECT); if (!mcs_client_begin(rdp->mcs)) return FALSE; } for (timeout = 0; timeout < freerdp_settings_get_uint32(settings, FreeRDP_TcpAckTimeout); timeout += 100) { if (rdp_check_fds(rdp) < 0) { freerdp_set_last_error_if_not(rdp->context, FREERDP_ERROR_CONNECT_TRANSPORT_FAILED); return FALSE; } if (rdp_get_state(rdp) == CONNECTION_STATE_ACTIVE) return TRUE; Sleep(100); } WLog_ERR(TAG, "Timeout waiting for activation"); freerdp_set_last_error_if_not(rdp->context, FREERDP_ERROR_CONNECT_ACTIVATION_TIMEOUT); return FALSE; } BOOL rdp_client_disconnect(rdpRdp* rdp) { rdpContext* context; if (!rdp || !rdp->settings || !rdp->context) return FALSE; context = rdp->context; if (rdp->nego) { if (!nego_disconnect(rdp->nego)) return FALSE; } if (!rdp_reset(rdp)) return FALSE; 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); context->codecs = NULL; return TRUE; } BOOL rdp_client_disconnect_and_clear(rdpRdp* rdp) { rdpContext* context; if (!rdp_client_disconnect(rdp)) return FALSE; WINPR_ASSERT(rdp); context = rdp->context; WINPR_ASSERT(context); if (freerdp_get_last_error(context) == FREERDP_ERROR_CONNECT_CANCELLED) return FALSE; context->LastError = FREERDP_ERROR_SUCCESS; clearChannelError(context); return utils_reset_abort(rdp); } 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)) { if (!freerdp_settings_set_string(settings, FreeRDP_ServerHostname, settings->RedirectionTargetFQDN)) return FALSE; return TRUE; } } return FALSE; } static BOOL rdp_client_redirect_try_ip(rdpSettings* settings) { if (settings->RedirectionFlags & LB_TARGET_NET_ADDRESS) { if (!freerdp_settings_set_string(settings, FreeRDP_ServerHostname, settings->TargetNetAddress)) 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)) { if (!freerdp_settings_set_string(settings, FreeRDP_ServerHostname, settings->RedirectionTargetNetBiosName)) return FALSE; return TRUE; } } return FALSE; } BOOL rdp_client_redirect(rdpRdp* rdp) { BOOL status; rdpSettings* settings; if (!rdp_client_disconnect_and_clear(rdp)) return FALSE; if (rdp_redirection_apply_settings(rdp) != 0) return FALSE; WINPR_ASSERT(rdp); settings = rdp->settings; WINPR_ASSERT(settings); 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) { if (!freerdp_settings_set_string( settings, FreeRDP_Username, freerdp_settings_get_string(settings, FreeRDP_RedirectionUsername))) return FALSE; } if (settings->RedirectionFlags & LB_DOMAIN) { if (!freerdp_settings_set_string( settings, FreeRDP_Domain, freerdp_settings_get_string(settings, FreeRDP_RedirectionDomain))) return FALSE; } WINPR_ASSERT(rdp->context); WINPR_ASSERT(rdp->context->instance); if (!IFCALLRESULT(TRUE, rdp->context->instance->Redirect, rdp->context->instance)) 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_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)) 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_CheckAndLogRequiredLength(TAG, s, 4)) return FALSE; Stream_Read_UINT32(s, rand_len); /* rand_len already includes 8 bytes of padding */ if (!Stream_CheckAndLogRequiredLength(TAG, 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 = tpkt_ensure_stream_consumed(s, length); 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) { const rdpMcsChannel* cur = &mcs->channels[0]; if (!mcs_send_channel_join_request(mcs, cur->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) { const rdpMcsChannel* cur = &mcs->channels[0]; if (!mcs_send_channel_join_request(mcs, cur->ChannelId)) return FALSE; allJoined = FALSE; } } else { for (i = 0; i < mcs->channelCount; i++) { rdpMcsChannel* cur = &mcs->channels[i]; if (cur->joined) continue; if (cur->ChannelId != channelId) return FALSE; cur->joined = TRUE; break; } if (i + 1 < mcs->channelCount) { const rdpMcsChannel* cur = &mcs->channels[i + 1]; if (!mcs_send_channel_join_request(mcs, cur->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) { size_t pos; UINT16 length; UINT16 channelId; /* If the MCS message channel has been joined... */ if (rdp->mcs->messageChannelId != 0) { /* Process any MCS message channel PDUs. */ pos = Stream_GetPosition(s); 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 tpkt_ensure_stream_consumed(s, length); } } Stream_SetPosition(s, pos); } 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) { size_t pos; UINT16 width; UINT16 height; UINT16 length; width = rdp->settings->DesktopWidth; height = rdp->settings->DesktopHeight; pos = Stream_GetPosition(s); if (!rdp_recv_demand_active(rdp, s)) { int rc; UINT16 channelId; Stream_SetPosition(s, pos); if (!rdp_recv_get_active_header(rdp, s, &channelId, &length)) return -1; /* 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. */ rc = rdp_recv_out_of_sequence_pdu(rdp, s); if (rc < 0) return rc; if (!tpkt_ensure_stream_consumed(s, length)) return -1; return rc; } if (freerdp_shall_disconnect_context(rdp->context)) 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, CONNECTION_STATE state) { int status = 0; WLog_DBG(TAG, "%s %s --> %s", __FUNCTION__, rdp_get_state_string(rdp), rdp_state_string(state)); rdp_set_state(rdp, state); switch (state) { case CONNECTION_STATE_FINALIZATION: update_reset_state(rdp->update); rdp->finalize_sc_pdus = 0; break; case CONNECTION_STATE_ACTIVE: { ActivatedEventArgs activatedEvent; rdpContext* context = rdp->context; EventArgsInit(&activatedEvent, "libfreerdp"); activatedEvent.firstActivation = !rdp->deactivation_reactivation; PubSub_OnActivated(context->pubSub, context, &activatedEvent); } break; default: break; } { ConnectionStateChangeEventArgs stateEvent; rdpContext* context = rdp->context; EventArgsInit(&stateEvent, "libfreerdp"); stateEvent.state = rdp_get_state(rdp); stateEvent.active = rdp_get_state(rdp) == CONNECTION_STATE_ACTIVE; PubSub_OnConnectionStateChange(context->pubSub, context, &stateEvent); } return status; } BOOL rdp_server_accept_nego(rdpRdp* rdp, wStream* s) { UINT32 SelectedProtocol = 0; UINT32 RequestedProtocols; BOOL status; rdpSettings* settings; rdpNego* nego; WINPR_ASSERT(rdp); WINPR_ASSERT(s); settings = rdp->settings; WINPR_ASSERT(settings); nego = rdp->nego; WINPR_ASSERT(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++) { rdpMcsChannel* cur = &mcs->channels[i]; WLog_INFO(TAG, " %s", cur->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++) { rdpMcsChannel* cur = &mcs->channels[i]; if (cur->ChannelId == channelId) cur->joined = TRUE; if (!cur->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, UINT16 pduLength) { freerdp_peer* peer = rdp->context->peer; if (rdp_get_state(rdp) != CONNECTION_STATE_CAPABILITIES_EXCHANGE) return FALSE; if (!rdp_recv_confirm_active(rdp, s, pduLength)) 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; } BOOL rdp_server_transition_to_state(rdpRdp* rdp, CONNECTION_STATE state) { BOOL status = FALSE; freerdp_peer* client = NULL; const CONNECTION_STATE cstate = rdp_get_state(rdp); if (cstate >= CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT) client = rdp->context->peer; if (cstate < CONNECTION_STATE_ACTIVE) { if (client) client->activated = FALSE; } WLog_DBG(TAG, "%s %s --> %s", __FUNCTION__, rdp_get_state_string(rdp), rdp_state_string(state)); if (!rdp_set_state(rdp, state)) goto fail; switch (state) { case CONNECTION_STATE_CAPABILITIES_EXCHANGE: rdp->AwaitCapabilities = FALSE; break; case CONNECTION_STATE_FINALIZATION: rdp->finalize_sc_pdus = 0; break; case 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) goto fail; } if (rdp_get_state(rdp) >= CONNECTION_STATE_ACTIVE) { IFCALLRET(client->Activate, client->activated, client); if (!client->activated) goto fail; } } break; default: break; } status = TRUE; fail: return status; } const char* rdp_client_connection_state_string(int state) { switch (state) { case CLIENT_STATE_INITIAL: return "CLIENT_STATE_INITIAL"; case CLIENT_STATE_PRECONNECT_PASSED: return "CLIENT_STATE_PRECONNECT_PASSED"; case CLIENT_STATE_POSTCONNECT_PASSED: return "CLIENT_STATE_POSTCONNECT_PASSED"; default: return "UNKNOWN"; } } const char* rdp_state_string(CONNECTION_STATE state) { switch (state) { case CONNECTION_STATE_INITIAL: return "CONNECTION_STATE_INITIAL"; case CONNECTION_STATE_NEGO: return "CONNECTION_STATE_NEGO"; case CONNECTION_STATE_NLA: return "CONNECTION_STATE_NLA"; case CONNECTION_STATE_MCS_CONNECT: return "CONNECTION_STATE_MCS_CONNECT"; case CONNECTION_STATE_MCS_ERECT_DOMAIN: return "CONNECTION_STATE_MCS_ERECT_DOMAIN"; case CONNECTION_STATE_MCS_ATTACH_USER: return "CONNECTION_STATE_MCS_ATTACH_USER"; case CONNECTION_STATE_MCS_CHANNEL_JOIN: return "CONNECTION_STATE_MCS_CHANNEL_JOIN"; case CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT: return "CONNECTION_STATE_RDP_SECURITY_COMMENCEMENT"; case CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE: return "CONNECTION_STATE_SECURE_SETTINGS_EXCHANGE"; case CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT: return "CONNECTION_STATE_CONNECT_TIME_AUTO_DETECT"; case CONNECTION_STATE_LICENSING: return "CONNECTION_STATE_LICENSING"; case CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING: return "CONNECTION_STATE_MULTITRANSPORT_BOOTSTRAPPING"; case CONNECTION_STATE_CAPABILITIES_EXCHANGE: return "CONNECTION_STATE_CAPABILITIES_EXCHANGE"; case CONNECTION_STATE_FINALIZATION: return "CONNECTION_STATE_FINALIZATION"; case CONNECTION_STATE_ACTIVE: return "CONNECTION_STATE_ACTIVE"; default: return "UNKNOWN"; } } CONNECTION_STATE rdp_get_state(const rdpRdp* rdp) { WINPR_ASSERT(rdp); return rdp->state; } BOOL rdp_set_state(rdpRdp* rdp, CONNECTION_STATE state) { WINPR_ASSERT(rdp); rdp->state = state; return TRUE; } const char* rdp_get_state_string(rdpRdp* rdp) { CONNECTION_STATE state = rdp_get_state(rdp); return rdp_state_string(state); } BOOL rdp_channels_from_mcs(rdpSettings* settings, const rdpRdp* rdp) { size_t x; const rdpMcs* mcs; WINPR_ASSERT(rdp); mcs = rdp->mcs; WINPR_ASSERT(mcs); if (!freerdp_settings_set_pointer_len(settings, FreeRDP_ChannelDefArray, NULL, mcs->channelCount)) return FALSE; for (x = 0; x < mcs->channelCount; x++) { const rdpMcsChannel* mchannel = &mcs->channels[x]; CHANNEL_DEF cur = { 0 }; memcpy(cur.name, mchannel->Name, sizeof(cur.name)); cur.options = mchannel->options; if (!freerdp_settings_set_pointer_array(settings, FreeRDP_ChannelDefArray, x, &cur)) return FALSE; } return TRUE; }