/* * SSLv3/TLSv1 server-side functions * * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * * 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 "common.h" #if defined(MBEDTLS_SSL_SRV_C) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include #define mbedtls_calloc calloc #define mbedtls_free free #endif #include "mbedtls/ssl.h" #include "mbedtls/ssl_internal.h" #include "mbedtls/debug.h" #include "mbedtls/error.h" #include "mbedtls/platform_util.h" #include #if defined(MBEDTLS_ECP_C) #include "mbedtls/ecp.h" #endif #if defined(MBEDTLS_HAVE_TIME) #include "mbedtls/platform_time.h" #endif #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl, const unsigned char *info, size_t ilen ) { if( ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER ) return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); mbedtls_free( ssl->cli_id ); if( ( ssl->cli_id = mbedtls_calloc( 1, ilen ) ) == NULL ) return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); memcpy( ssl->cli_id, info, ilen ); ssl->cli_id_len = ilen; return( 0 ); } void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf, mbedtls_ssl_cookie_write_t *f_cookie_write, mbedtls_ssl_cookie_check_t *f_cookie_check, void *p_cookie ) { conf->f_cookie_write = f_cookie_write; conf->f_cookie_check = f_cookie_check; conf->p_cookie = p_cookie; } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t servername_list_size, hostname_len; const unsigned char *p; MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) ); if( len < 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( servername_list_size + 2 != len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } p = buf + 2; while( servername_list_size > 2 ) { hostname_len = ( ( p[1] << 8 ) | p[2] ); if( hostname_len + 3 > servername_list_size ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME ) { ret = ssl->conf->f_sni( ssl->conf->p_sni, ssl, p + 3, hostname_len ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } servername_list_size -= hostname_len + 3; p += hostname_len + 3; } if( servername_list_size != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) static int ssl_conf_has_psk_or_cb( mbedtls_ssl_config const *conf ) { if( conf->f_psk != NULL ) return( 1 ); if( conf->psk_identity_len == 0 || conf->psk_identity == NULL ) return( 0 ); if( conf->psk != NULL && conf->psk_len != 0 ) return( 1 ); #if defined(MBEDTLS_USE_PSA_CRYPTO) if( ! mbedtls_svc_key_id_is_null( conf->psk_opaque ) ) return( 1 ); #endif /* MBEDTLS_USE_PSA_CRYPTO */ return( 0 ); } #if defined(MBEDTLS_USE_PSA_CRYPTO) static int ssl_use_opaque_psk( mbedtls_ssl_context const *ssl ) { if( ssl->conf->f_psk != NULL ) { /* If we've used a callback to select the PSK, * the static configuration is irrelevant. */ if( ! mbedtls_svc_key_id_is_null( ssl->handshake->psk_opaque ) ) return( 1 ); return( 0 ); } if( ! mbedtls_svc_key_id_is_null( ssl->conf->psk_opaque ) ) return( 1 ); return( 0 ); } #endif /* MBEDTLS_USE_PSA_CRYPTO */ #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) { /* Check verify-data in constant-time. The length OTOH is no secret */ if( len != 1 + ssl->verify_data_len || buf[0] != ssl->verify_data_len || mbedtls_ssl_safer_memcmp( buf + 1, ssl->peer_verify_data, ssl->verify_data_len ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } else #endif /* MBEDTLS_SSL_RENEGOTIATION */ { if( len != 1 || buf[0] != 0x0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; } return( 0 ); } #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* * Status of the implementation of signature-algorithms extension: * * Currently, we are only considering the signature-algorithm extension * to pick a ciphersuite which allows us to send the ServerKeyExchange * message with a signature-hash combination that the user allows. * * We do *not* check whether all certificates in our certificate * chain are signed with an allowed signature-hash pair. * This needs to be done at a later stage. * */ static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t sig_alg_list_size; const unsigned char *p; const unsigned char *end = buf + len; mbedtls_md_type_t md_cur; mbedtls_pk_type_t sig_cur; if ( len < 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( sig_alg_list_size + 2 != len || sig_alg_list_size % 2 != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Currently we only guarantee signing the ServerKeyExchange message according * to the constraints specified in this extension (see above), so it suffices * to remember only one suitable hash for each possible signature algorithm. * * This will change when we also consider certificate signatures, * in which case we will need to remember the whole signature-hash * pair list from the extension. */ for( p = buf + 2; p < end; p += 2 ) { /* Silently ignore unknown signature or hash algorithms. */ if( ( sig_cur = mbedtls_ssl_pk_alg_from_sig( p[1] ) ) == MBEDTLS_PK_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext" " unknown sig alg encoding %d", p[1] ) ); continue; } /* Check if we support the hash the user proposes */ md_cur = mbedtls_ssl_md_alg_from_hash( p[0] ); if( md_cur == MBEDTLS_MD_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:" " unknown hash alg encoding %d", p[0] ) ); continue; } if( mbedtls_ssl_check_sig_hash( ssl, md_cur ) == 0 ) { mbedtls_ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:" " match sig %u and hash %u", (unsigned) sig_cur, (unsigned) md_cur ) ); } else { MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: " "hash alg %u not supported", (unsigned) md_cur ) ); } } return( 0 ); } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t list_size, our_size; const unsigned char *p; const mbedtls_ecp_curve_info *curve_info, **curves; if ( len < 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( list_size + 2 != len || list_size % 2 != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Should never happen unless client duplicates the extension */ if( ssl->handshake->curves != NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Don't allow our peer to make us allocate too much memory, * and leave room for a final 0 */ our_size = list_size / 2 + 1; if( our_size > MBEDTLS_ECP_DP_MAX ) our_size = MBEDTLS_ECP_DP_MAX; if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR ); return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); } ssl->handshake->curves = curves; p = buf + 2; while( list_size > 0 && our_size > 1 ) { curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] ); if( curve_info != NULL ) { *curves++ = curve_info; our_size--; } list_size -= 2; p += 2; } return( 0 ); } static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t list_size; const unsigned char *p; if( len == 0 || (size_t)( buf[0] + 1 ) != len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } list_size = buf[0]; p = buf + 1; while( list_size > 0 ) { if( p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED || p[0] == MBEDTLS_ECP_PF_COMPRESSED ) { #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) ssl->handshake->ecdh_ctx.point_format = p[0]; #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) ssl->handshake->ecjpake_ctx.point_format = p[0]; #endif MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) ); return( 0 ); } list_size--; p++; } return( 0 ); } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) ); return( 0 ); } if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx, buf, len ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( ret ); } /* Only mark the extension as OK when we're sure it is */ ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK; return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->session_negotiate->mfl_code = buf[0]; return( 0 ); } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t peer_cid_len; /* CID extension only makes sense in DTLS */ if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Quoting draft-ietf-tls-dtls-connection-id-05 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05 * * struct { * opaque cid<0..2^8-1>; * } ConnectionId; */ if( len < 1 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } peer_cid_len = *buf++; len--; if( len != peer_cid_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Ignore CID if the user has disabled its use. */ if( ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED ) { /* Leave ssl->handshake->cid_in_use in its default * value of MBEDTLS_SSL_CID_DISABLED. */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "Client sent CID extension, but CID disabled" ) ); return( 0 ); } if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED; ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len; memcpy( ssl->handshake->peer_cid, buf, peer_cid_len ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) ); MBEDTLS_SSL_DEBUG_BUF( 3, "Client CID", buf, peer_cid_len ); return( 0 ); } #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED ) ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED; return( 0 ); } #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED && ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 ) { ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED; } return( 0 ); } #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED && ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 ) { ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED; } return( 0 ); } #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; mbedtls_ssl_session session; mbedtls_ssl_session_init( &session ); if( ssl->conf->f_ticket_parse == NULL || ssl->conf->f_ticket_write == NULL ) { return( 0 ); } /* Remember the client asked us to send a new ticket */ ssl->handshake->new_session_ticket = 1; MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %" MBEDTLS_PRINTF_SIZET, len ) ); if( len == 0 ) return( 0 ); #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_RENEGOTIATION */ /* * Failures are ok: just ignore the ticket and proceed. */ if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session, buf, len ) ) != 0 ) { mbedtls_ssl_session_free( &session ); if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) ); else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED ) MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) ); else MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret ); return( 0 ); } /* * Keep the session ID sent by the client, since we MUST send it back to * inform them we're accepting the ticket (RFC 5077 section 3.4) */ session.id_len = ssl->session_negotiate->id_len; memcpy( &session.id, ssl->session_negotiate->id, session.id_len ); mbedtls_ssl_session_free( ssl->session_negotiate ); memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) ); /* Zeroize instead of free as we copied the content */ mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) ); ssl->handshake->resume = 1; /* Don't send a new ticket after all, this one is OK */ ssl->handshake->new_session_ticket = 0; return( 0 ); } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_ALPN) static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t list_len, cur_len, ours_len; const unsigned char *theirs, *start, *end; const char **ours; /* If ALPN not configured, just ignore the extension */ if( ssl->conf->alpn_list == NULL ) return( 0 ); /* * opaque ProtocolName<1..2^8-1>; * * struct { * ProtocolName protocol_name_list<2..2^16-1> * } ProtocolNameList; */ /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */ if( len < 4 ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } list_len = ( buf[0] << 8 ) | buf[1]; if( list_len != len - 2 ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Validate peer's list (lengths) */ start = buf + 2; end = buf + len; for( theirs = start; theirs != end; theirs += cur_len ) { cur_len = *theirs++; /* Current identifier must fit in list */ if( cur_len > (size_t)( end - theirs ) ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Empty strings MUST NOT be included */ if( cur_len == 0 ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } /* * Use our order of preference */ for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ ) { ours_len = strlen( *ours ); for( theirs = start; theirs != end; theirs += cur_len ) { cur_len = *theirs++; if( cur_len == ours_len && memcmp( theirs, *ours, cur_len ) == 0 ) { ssl->alpn_chosen = *ours; return( 0 ); } } } /* If we get there, no match was found */ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* MBEDTLS_SSL_ALPN */ #if defined(MBEDTLS_SSL_DTLS_SRTP) static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET; size_t i,j; size_t profile_length; uint16_t mki_length; /*! 2 bytes for profile length and 1 byte for mki len */ const size_t size_of_lengths = 3; /* If use_srtp is not configured, just ignore the extension */ if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) || ( ssl->conf->dtls_srtp_profile_list == NULL ) || ( ssl->conf->dtls_srtp_profile_list_len == 0 ) ) { return( 0 ); } /* RFC5764 section 4.1.1 * uint8 SRTPProtectionProfile[2]; * * struct { * SRTPProtectionProfiles SRTPProtectionProfiles; * opaque srtp_mki<0..255>; * } UseSRTPData; * SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>; */ /* * Min length is 5: at least one protection profile(2 bytes) * and length(2 bytes) + srtp_mki length(1 byte) * Check here that we have at least 2 bytes of protection profiles length * and one of srtp_mki length */ if( len < size_of_lengths ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET; /* first 2 bytes are protection profile length(in bytes) */ profile_length = ( buf[0] << 8 ) | buf[1]; buf += 2; /* The profile length cannot be bigger than input buffer size - lengths fields */ if( profile_length > len - size_of_lengths || profile_length % 2 != 0 ) /* profiles are 2 bytes long, so the length must be even */ { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * parse the extension list values are defined in * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml */ for( j = 0; j < profile_length; j += 2 ) { uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1]; client_protection = mbedtls_ssl_check_srtp_profile_value( protection_profile_value ); if( client_protection != MBEDTLS_TLS_SRTP_UNSET ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s", mbedtls_ssl_get_srtp_profile_as_string( client_protection ) ) ); } else { continue; } /* check if suggested profile is in our list */ for( i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++) { if( client_protection == ssl->conf->dtls_srtp_profile_list[i] ) { ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i]; MBEDTLS_SSL_DEBUG_MSG( 3, ( "selected srtp profile: %s", mbedtls_ssl_get_srtp_profile_as_string( client_protection ) ) ); break; } } if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET ) break; } buf += profile_length; /* buf points to the mki length */ mki_length = *buf; buf++; if( mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH || mki_length + profile_length + size_of_lengths != len ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Parse the mki only if present and mki is supported locally */ if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED && mki_length > 0 ) { ssl->dtls_srtp_info.mki_len = mki_length; memcpy( ssl->dtls_srtp_info.mki_value, buf, mki_length ); MBEDTLS_SSL_DEBUG_BUF( 3, "using mki", ssl->dtls_srtp_info.mki_value, ssl->dtls_srtp_info.mki_len ); } return( 0 ); } #endif /* MBEDTLS_SSL_DTLS_SRTP */ /* * Auxiliary functions for ServerHello parsing and related actions */ #if defined(MBEDTLS_X509_CRT_PARSE_C) /* * Return 0 if the given key uses one of the acceptable curves, -1 otherwise */ #if defined(MBEDTLS_ECDSA_C) static int ssl_check_key_curve( mbedtls_pk_context *pk, const mbedtls_ecp_curve_info **curves ) { const mbedtls_ecp_curve_info **crv = curves; mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id; while( *crv != NULL ) { if( (*crv)->grp_id == grp_id ) return( 0 ); crv++; } return( -1 ); } #endif /* MBEDTLS_ECDSA_C */ /* * Try picking a certificate for this ciphersuite, * return 0 on success and -1 on failure. */ static int ssl_pick_cert( mbedtls_ssl_context *ssl, const mbedtls_ssl_ciphersuite_t * ciphersuite_info ) { mbedtls_ssl_key_cert *cur, *list, *fallback = NULL; mbedtls_pk_type_t pk_alg = mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); uint32_t flags; #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) if( ssl->handshake->sni_key_cert != NULL ) list = ssl->handshake->sni_key_cert; else #endif list = ssl->conf->key_cert; if( pk_alg == MBEDTLS_PK_NONE ) return( 0 ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) ); if( list == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) ); return( -1 ); } for( cur = list; cur != NULL; cur = cur->next ) { flags = 0; MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate", cur->cert ); if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) ); continue; } /* * This avoids sending the client a cert it'll reject based on * keyUsage or other extensions. * * It also allows the user to provision different certificates for * different uses based on keyUsage, eg if they want to avoid signing * and decrypting with the same RSA key. */ if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info, MBEDTLS_SSL_IS_SERVER, &flags ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: " "(extended) key usage extension" ) ); continue; } #if defined(MBEDTLS_ECDSA_C) if( pk_alg == MBEDTLS_PK_ECDSA && ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) ); continue; } #endif /* * Try to select a SHA-1 certificate for pre-1.2 clients, but still * present them a SHA-higher cert rather than failing if it's the only * one we got that satisfies the other conditions. */ if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 && cur->cert->sig_md != MBEDTLS_MD_SHA1 ) { if( fallback == NULL ) fallback = cur; { MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: " "sha-2 with pre-TLS 1.2 client" ) ); continue; } } /* If we get there, we got a winner */ break; } if( cur == NULL ) cur = fallback; /* Do not update ssl->handshake->key_cert unless there is a match */ if( cur != NULL ) { ssl->handshake->key_cert = cur; MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate", ssl->handshake->key_cert->cert ); return( 0 ); } return( -1 ); } #endif /* MBEDTLS_X509_CRT_PARSE_C */ /* * Check if a given ciphersuite is suitable for use with our config/keys/etc * Sets ciphersuite_info only if the suite matches. */ static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id, const mbedtls_ssl_ciphersuite_t **ciphersuite_info ) { const mbedtls_ssl_ciphersuite_t *suite_info; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) mbedtls_pk_type_t sig_type; #endif suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id ); if( suite_info == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %#04x (%s)", (unsigned int) suite_id, suite_info->name ) ); if( suite_info->min_minor_ver > ssl->minor_ver || suite_info->max_minor_ver < ssl->minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) ); return( 0 ); } #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) ) return( 0 ); #endif #if defined(MBEDTLS_ARC4_C) if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED && suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) ); return( 0 ); } #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE && ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake " "not configured or ext missing" ) ); return( 0 ); } #endif #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) && ( ssl->handshake->curves == NULL || ssl->handshake->curves[0] == NULL ) ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: " "no common elliptic curve" ) ); return( 0 ); } #endif #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) /* If the ciphersuite requires a pre-shared key and we don't * have one, skip it now rather than failing later */ if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) && ssl_conf_has_psk_or_cb( ssl->conf ) == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) ); return( 0 ); } #endif #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* If the ciphersuite requires signing, check whether * a suitable hash algorithm is present. */ if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info ); if( sig_type != MBEDTLS_PK_NONE && mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm " "for signature algorithm %u", (unsigned) sig_type ) ); return( 0 ); } } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_X509_CRT_PARSE_C) /* * Final check: if ciphersuite requires us to have a * certificate/key of a particular type: * - select the appropriate certificate if we have one, or * - try the next ciphersuite if we don't * This must be done last since we modify the key_cert list. */ if( ssl_pick_cert( ssl, suite_info ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: " "no suitable certificate" ) ); return( 0 ); } #endif *ciphersuite_info = suite_info; return( 0 ); } #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl ) { int ret, got_common_suite; unsigned int i, j; size_t n; unsigned int ciph_len, sess_len, chal_len; unsigned char *buf, *p; const int *ciphersuites; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) ); #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* MBEDTLS_SSL_RENEGOTIATION */ buf = ssl->in_hdr; MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d", buf[2] ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d", ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]", buf[3], buf[4] ) ); /* * SSLv2 Client Hello * * Record layer: * 0 . 1 message length * * SSL layer: * 2 . 2 message type * 3 . 4 protocol version */ if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO || buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF; if( n < 17 || n > 512 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3; ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver ) ? buf[4] : ssl->conf->max_minor_ver; if( ssl->minor_ver < ssl->conf->min_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION ); return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION ); } ssl->handshake->max_major_ver = buf[3]; ssl->handshake->max_minor_ver = buf[4]; if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); return( ret ); } ssl->handshake->update_checksum( ssl, buf + 2, n ); buf = ssl->in_msg; n = ssl->in_left - 5; /* * 0 . 1 ciphersuitelist length * 2 . 3 session id length * 4 . 5 challenge length * 6 . .. ciphersuitelist * .. . .. session id * .. . .. challenge */ MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n ); ciph_len = ( buf[0] << 8 ) | buf[1]; sess_len = ( buf[2] << 8 ) | buf[3]; chal_len = ( buf[4] << 8 ) | buf[5]; MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %u, sess_len: %u, chal_len: %u", ciph_len, sess_len, chal_len ) ); /* * Make sure each parameter length is valid */ if( ciph_len < 3 || ( ciph_len % 3 ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( sess_len > 32 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( chal_len < 8 || chal_len > 32 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( n != 6 + ciph_len + sess_len + chal_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", buf + 6, ciph_len ); MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 6 + ciph_len, sess_len ); MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge", buf + 6 + ciph_len + sess_len, chal_len ); p = buf + 6 + ciph_len; ssl->session_negotiate->id_len = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len ); p += sess_len; memset( ssl->handshake->randbytes, 0, 64 ); memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len ); /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 ) { if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) ); #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV " "during renegotiation" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* MBEDTLS_SSL_RENEGOTIATION */ ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; break; } } #if defined(MBEDTLS_SSL_FALLBACK_SCSV) for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 ) { if( p[0] == 0 && p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) && p[2] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) ); if( ssl->minor_ver < ssl->conf->max_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } break; } } #endif /* MBEDTLS_SSL_FALLBACK_SCSV */ got_common_suite = 0; ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE) for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 ) for( i = 0; ciphersuites[i] != 0; i++ ) #else for( i = 0; ciphersuites[i] != 0; i++ ) for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 ) #endif { if( p[0] != 0 || p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) || p[2] != ( ( ciphersuites[i] ) & 0xFF ) ) continue; got_common_suite = 1; if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i], &ciphersuite_info ) ) != 0 ) return( ret ); if( ciphersuite_info != NULL ) goto have_ciphersuite_v2; } if( got_common_suite ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, " "but none of them usable" ) ); return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE ); } else { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) ); return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN ); } have_ciphersuite_v2: MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) ); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->handshake->ciphersuite_info = ciphersuite_info; /* * SSLv2 Client Hello relevant renegotiation security checks */ if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->in_left = 0; ssl->state++; MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */ /* This function doesn't alert on errors that happen early during ClientHello parsing because they might indicate that the client is not talking SSL/TLS at all and would not understand our alert. */ static int ssl_parse_client_hello( mbedtls_ssl_context *ssl ) { int ret, got_common_suite; size_t i, j; size_t ciph_offset, comp_offset, ext_offset; size_t msg_len, ciph_len, sess_len, comp_len, ext_len; #if defined(MBEDTLS_SSL_PROTO_DTLS) size_t cookie_offset, cookie_len; #endif unsigned char *buf, *p, *ext; #if defined(MBEDTLS_SSL_RENEGOTIATION) int renegotiation_info_seen = 0; #endif int handshake_failure = 0; const int *ciphersuites; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; int major, minor; /* If there is no signature-algorithm extension present, * we need to fall back to the default values for allowed * signature-hash pairs. */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) int sig_hash_alg_ext_present = 0; #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) ); #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) read_record_header: #endif /* * If renegotiating, then the input was read with mbedtls_ssl_read_record(), * otherwise read it ourselves manually in order to support SSLv2 * ClientHello, which doesn't use the same record layer format. */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE ) #endif { if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 ) { /* No alert on a read error. */ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); return( ret ); } } buf = ssl->in_hdr; #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM ) #endif if( ( buf[0] & 0x80 ) != 0 ) return( ssl_parse_client_hello_v2( ssl ) ); #endif MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_in_hdr_len( ssl ) ); /* * SSLv3/TLS Client Hello * * Record layer: * 0 . 0 message type * 1 . 2 protocol version * 3 . 11 DTLS: epoch + record sequence number * 3 . 4 message length */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d", buf[0] ) ); if( buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d", ( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]", buf[1], buf[2] ) ); mbedtls_ssl_read_version( &major, &minor, ssl->conf->transport, buf + 1 ); /* According to RFC 5246 Appendix E.1, the version here is typically * "{03,00}, the lowest version number supported by the client, [or] the * value of ClientHello.client_version", so the only meaningful check here * is the major version shouldn't be less than 3 */ if( major < MBEDTLS_SSL_MAJOR_VERSION_3 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* For DTLS if this is the initial handshake, remember the client sequence * number to use it in our next message (RFC 6347 4.2.1) */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM #if defined(MBEDTLS_SSL_RENEGOTIATION) && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE #endif ) { /* Epoch should be 0 for initial handshakes */ if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } memcpy( ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6 ); #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record, discarding" ) ); ssl->next_record_offset = 0; ssl->in_left = 0; goto read_record_header; } /* No MAC to check yet, so we can update right now */ mbedtls_ssl_dtls_replay_update( ssl ); #endif } #endif /* MBEDTLS_SSL_PROTO_DTLS */ msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1]; #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) { /* Set by mbedtls_ssl_read_record() */ msg_len = ssl->in_hslen; } else #endif { if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( ( ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_in_hdr_len( ssl ) + msg_len ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); return( ret ); } /* Done reading this record, get ready for the next one */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ssl->next_record_offset = msg_len + mbedtls_ssl_in_hdr_len( ssl ); else #endif ssl->in_left = 0; } buf = ssl->in_msg; MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, msg_len ); ssl->handshake->update_checksum( ssl, buf, msg_len ); /* * Handshake layer: * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 DTLS only: message seqence number * 6 . 8 DTLS only: fragment offset * 9 . 11 DTLS only: fragment length */ if( msg_len < mbedtls_ssl_hs_hdr_len( ssl ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) ); if( buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d", ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) ); /* We don't support fragmentation of ClientHello (yet?) */ if( buf[1] != 0 || msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { /* * Copy the client's handshake message_seq on initial handshakes, * check sequence number on renego. */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS ) { /* This couldn't be done in ssl_prepare_handshake_record() */ unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; if( cli_msg_seq != ssl->handshake->in_msg_seq ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: " "%u (expected %u)", cli_msg_seq, ssl->handshake->in_msg_seq ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->handshake->in_msg_seq++; } else #endif { unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; ssl->handshake->out_msg_seq = cli_msg_seq; ssl->handshake->in_msg_seq = cli_msg_seq + 1; } /* * For now we don't support fragmentation, so make sure * fragment_offset == 0 and fragment_length == length */ if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 || memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) ); return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); } } #endif /* MBEDTLS_SSL_PROTO_DTLS */ buf += mbedtls_ssl_hs_hdr_len( ssl ); msg_len -= mbedtls_ssl_hs_hdr_len( ssl ); /* * ClientHello layer: * 0 . 1 protocol version * 2 . 33 random bytes (starting with 4 bytes of Unix time) * 34 . 35 session id length (1 byte) * 35 . 34+x session id * 35+x . 35+x DTLS only: cookie length (1 byte) * 36+x . .. DTLS only: cookie * .. . .. ciphersuite list length (2 bytes) * .. . .. ciphersuite list * .. . .. compression alg. list length (1 byte) * .. . .. compression alg. list * .. . .. extensions length (2 bytes, optional) * .. . .. extensions (optional) */ /* * Minimal length (with everything empty and extensions omitted) is * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can * read at least up to session id length without worrying. */ if( msg_len < 38 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check and save the protocol version */ MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 ); mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver, ssl->conf->transport, buf ); ssl->handshake->max_major_ver = ssl->major_ver; ssl->handshake->max_minor_ver = ssl->minor_ver; if( ssl->major_ver < ssl->conf->min_major_ver || ssl->minor_ver < ssl->conf->min_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION ); return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION ); } if( ssl->major_ver > ssl->conf->max_major_ver ) { ssl->major_ver = ssl->conf->max_major_ver; ssl->minor_ver = ssl->conf->max_minor_ver; } else if( ssl->minor_ver > ssl->conf->max_minor_ver ) ssl->minor_ver = ssl->conf->max_minor_ver; /* * Save client random (inc. Unix time) */ MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 ); memcpy( ssl->handshake->randbytes, buf + 2, 32 ); /* * Check the session ID length and save session ID */ sess_len = buf[34]; if( sess_len > sizeof( ssl->session_negotiate->id ) || sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len ); ssl->session_negotiate->id_len = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, buf + 35, ssl->session_negotiate->id_len ); /* * Check the cookie length and content */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { cookie_offset = 35 + sess_len; cookie_len = buf[cookie_offset]; if( cookie_offset + 1 + cookie_len + 2 > msg_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie", buf + cookie_offset + 1, cookie_len ); #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) if( ssl->conf->f_cookie_check != NULL #if defined(MBEDTLS_SSL_RENEGOTIATION) && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE #endif ) { if( ssl->conf->f_cookie_check( ssl->conf->p_cookie, buf + cookie_offset + 1, cookie_len, ssl->cli_id, ssl->cli_id_len ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) ); ssl->handshake->verify_cookie_len = 1; } else { MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) ); ssl->handshake->verify_cookie_len = 0; } } else #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ { /* We know we didn't send a cookie, so it should be empty */ if( cookie_len != 0 ) { /* This may be an attacker's probe, so don't send an alert */ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) ); } /* * Check the ciphersuitelist length (will be parsed later) */ ciph_offset = cookie_offset + 1 + cookie_len; } else #endif /* MBEDTLS_SSL_PROTO_DTLS */ ciph_offset = 35 + sess_len; ciph_len = ( buf[ciph_offset + 0] << 8 ) | ( buf[ciph_offset + 1] ); if( ciph_len < 2 || ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */ ( ciph_len % 2 ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", buf + ciph_offset + 2, ciph_len ); /* * Check the compression algorithms length and pick one */ comp_offset = ciph_offset + 2 + ciph_len; comp_len = buf[comp_offset]; if( comp_len < 1 || comp_len > 16 || comp_len + comp_offset + 1 > msg_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, compression", buf + comp_offset + 1, comp_len ); ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL; #if defined(MBEDTLS_ZLIB_SUPPORT) for( i = 0; i < comp_len; ++i ) { if( buf[comp_offset + 1 + i] == MBEDTLS_SSL_COMPRESS_DEFLATE ) { ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_DEFLATE; break; } } #endif /* See comments in ssl_write_client_hello() */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL; #endif /* Do not parse the extensions if the protocol is SSLv3 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) ) { #endif /* * Check the extension length */ ext_offset = comp_offset + 1 + comp_len; if( msg_len > ext_offset ) { if( msg_len < ext_offset + 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ext_len = ( buf[ext_offset + 0] << 8 ) | ( buf[ext_offset + 1] ); if( msg_len != ext_offset + 2 + ext_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } else ext_len = 0; ext = buf + ext_offset + 2; MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len ); while( ext_len != 0 ) { unsigned int ext_id; unsigned int ext_size; if ( ext_len < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) ); ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) ); if( ext_size + 4 > ext_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } switch( ext_id ) { #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) case MBEDTLS_TLS_EXT_SERVERNAME: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) ); if( ssl->conf->f_sni == NULL ) break; ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) ); #if defined(MBEDTLS_SSL_RENEGOTIATION) renegotiation_info_seen = 1; #endif ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) case MBEDTLS_TLS_EXT_SIG_ALG: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) ); ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); sig_hash_alg_ext_present = 1; break; #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) ); ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) ); ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT; ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) case MBEDTLS_TLS_EXT_ECJPAKE_KKPP: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) ); ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) ); ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) case MBEDTLS_TLS_EXT_TRUNCATED_HMAC: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) ); ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) case MBEDTLS_TLS_EXT_CID: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) ); ret = ssl_parse_cid_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) ); ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) ); ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) case MBEDTLS_TLS_EXT_SESSION_TICKET: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) ); ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_ALPN) case MBEDTLS_TLS_EXT_ALPN: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) ); ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_DTLS_SRTP) case MBEDTLS_TLS_EXT_USE_SRTP: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found use_srtp extension" ) ); ret = ssl_parse_use_srtp_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_DTLS_SRTP */ default: MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %u (ignoring)", ext_id ) ); } ext_len -= 4 + ext_size; ext += 4 + ext_size; } #if defined(MBEDTLS_SSL_PROTO_SSL3) } #endif #if defined(MBEDTLS_SSL_FALLBACK_SCSV) for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 ) { if( p[0] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) && p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) ); if( ssl->minor_ver < ssl->conf->max_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } break; } } #endif /* MBEDTLS_SSL_FALLBACK_SCSV */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* * Try to fall back to default hash SHA1 if the client * hasn't provided any preferred signature-hash combinations. */ if( sig_hash_alg_ext_present == 0 ) { mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1; if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 ) md_default = MBEDTLS_MD_NONE; mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default ); } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 ) { if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) ); #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV " "during renegotiation" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; break; } } /* * Renegotiation security checks */ if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) ); handshake_failure = 1; } #if defined(MBEDTLS_SSL_RENEGOTIATION) else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION && renegotiation_info_seen == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) ); handshake_failure = 1; } else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) ); handshake_failure = 1; } else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && renegotiation_info_seen == 1 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) ); handshake_failure = 1; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ if( handshake_failure == 1 ) { mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Search for a matching ciphersuite * (At the end because we need information from the EC-based extensions * and certificate from the SNI callback triggered by the SNI extension.) */ got_common_suite = 0; ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE) for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 ) for( i = 0; ciphersuites[i] != 0; i++ ) #else for( i = 0; ciphersuites[i] != 0; i++ ) for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 ) #endif { if( p[0] != MBEDTLS_BYTE_1( ciphersuites[i] ) || p[1] != MBEDTLS_BYTE_0( ciphersuites[i] )) continue; got_common_suite = 1; if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i], &ciphersuite_info ) ) != 0 ) return( ret ); if( ciphersuite_info != NULL ) goto have_ciphersuite; } if( got_common_suite ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, " "but none of them usable" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE ); } else { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ); return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN ); } have_ciphersuite: MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) ); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->handshake->ciphersuite_info = ciphersuite_info; ssl->state++; #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) mbedtls_ssl_recv_flight_completed( ssl ); #endif /* Debugging-only output for testsuite */ #if defined(MBEDTLS_DEBUG_C) && \ defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info ); if( sig_alg != MBEDTLS_PK_NONE ) { mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_alg ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d", mbedtls_ssl_hash_from_md_alg( md_alg ) ) ); } else { MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm " "%u - should not happen", (unsigned) sig_alg ) ); } } #endif MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) ); return( 0 ); } #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC ) & 0xFF ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) static void ssl_write_cid_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; size_t ext_len; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; *olen = 0; /* Skip writing the extension if we don't want to use it or if * the client hasn't offered it. */ if( ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED ) return; /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX * which is at most 255, so the increment cannot overflow. */ if( end < p || (size_t)( end - p ) < (unsigned)( ssl->own_cid_len + 5 ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding CID extension" ) ); /* * Quoting draft-ietf-tls-dtls-connection-id-05 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05 * * struct { * opaque cid<0..2^8-1>; * } ConnectionId; */ *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_CID ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_CID ); ext_len = (size_t) ssl->own_cid_len + 1; *p++ = MBEDTLS_CHAR_1( ext_len ); *p++ = MBEDTLS_CHAR_0( ext_len ); *p++ = (uint8_t) ssl->own_cid_len; memcpy( p, ssl->own_cid, ssl->own_cid_len ); *olen = ssl->own_cid_len + 5; } #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const mbedtls_ssl_ciphersuite_t *suite = NULL; const mbedtls_cipher_info_t *cipher = NULL; if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED || ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) { *olen = 0; return; } /* * RFC 7366: "If a server receives an encrypt-then-MAC request extension * from a client and then selects a stream or Authenticated Encryption * with Associated Data (AEAD) ciphersuite, it MUST NOT send an * encrypt-then-MAC response extension back to the client." */ if( ( suite = mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) == NULL || ( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL || cipher->mode != MBEDTLS_MODE_CBC ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED || ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret " "extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->handshake->new_session_ticket == 0 ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_SESSION_TICKET ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_SESSION_TICKET ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ); #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) { *p++ = 0x00; *p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF; *p++ = ssl->verify_data_len * 2 & 0xFF; memcpy( p, ssl->peer_verify_data, ssl->verify_data_len ); p += ssl->verify_data_len; memcpy( p, ssl->own_verify_data, ssl->verify_data_len ); p += ssl->verify_data_len; } else #endif /* MBEDTLS_SSL_RENEGOTIATION */ { *p++ = 0x00; *p++ = 0x01; *p++ = 0x00; } *olen = p - buf; } #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ); *p++ = 0x00; *p++ = 1; *p++ = ssl->session_negotiate->mfl_code; *olen = 5; } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; ((void) ssl); if( ( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) ); *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ); *p++ = 0x00; *p++ = 2; *p++ = 1; *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED; *olen = 6; } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; size_t kkpp_len; *olen = 0; /* Skip costly computation if not needed */ if( ssl->handshake->ciphersuite_info->key_exchange != MBEDTLS_KEY_EXCHANGE_ECJPAKE ) return; MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, ecjpake kkpp extension" ) ); if( end - p < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ); *p++ = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ); ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx, p + 2, end - p - 2, &kkpp_len, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret ); return; } *p++ = MBEDTLS_CHAR_1( kkpp_len ); *p++ = MBEDTLS_CHAR_0( kkpp_len ); *olen = kkpp_len + 4; } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_ALPN ) static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { if( ssl->alpn_chosen == NULL ) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) ); /* * 0 . 1 ext identifier * 2 . 3 ext length * 4 . 5 protocol list length * 6 . 6 protocol name length * 7 . 7+n protocol name */ buf[0] = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_ALPN ); buf[1] = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_ALPN ); *olen = 7 + strlen( ssl->alpn_chosen ); buf[2] = MBEDTLS_CHAR_1( *olen - 4 ); buf[3] = MBEDTLS_CHAR_0( *olen - 4 ); buf[4] = MBEDTLS_CHAR_1( *olen - 6 ); buf[5] = MBEDTLS_CHAR_0( *olen - 6 ); buf[6] = MBEDTLS_CHAR_0( *olen - 7 ); memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 ); } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */ #if defined(MBEDTLS_SSL_DTLS_SRTP ) && defined(MBEDTLS_SSL_PROTO_DTLS) static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { size_t mki_len = 0, ext_len = 0; uint16_t profile_value = 0; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; *olen = 0; if( ( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) || ( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET ) ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) ); if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED ) { mki_len = ssl->dtls_srtp_info.mki_len; } /* The extension total size is 9 bytes : * - 2 bytes for the extension tag * - 2 bytes for the total size * - 2 bytes for the protection profile length * - 2 bytes for the protection profile * - 1 byte for the mki length * + the actual mki length * Check we have enough room in the output buffer */ if( (size_t)( end - buf ) < mki_len + 9 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } /* extension */ buf[0] = MBEDTLS_CHAR_1( MBEDTLS_TLS_EXT_USE_SRTP ); buf[1] = MBEDTLS_CHAR_0( MBEDTLS_TLS_EXT_USE_SRTP ); /* * total length 5 and mki value: only one profile(2 bytes) * and length(2 bytes) and srtp_mki ) */ ext_len = 5 + mki_len; buf[2] = MBEDTLS_CHAR_1( ext_len ); buf[3] = MBEDTLS_CHAR_0( ext_len ); /* protection profile length: 2 */ buf[4] = 0x00; buf[5] = 0x02; profile_value = mbedtls_ssl_check_srtp_profile_value( ssl->dtls_srtp_info.chosen_dtls_srtp_profile ); if( profile_value != MBEDTLS_TLS_SRTP_UNSET ) { buf[6] = MBEDTLS_CHAR_1( profile_value ); buf[7] = MBEDTLS_CHAR_0( profile_value ); } else { MBEDTLS_SSL_DEBUG_MSG( 1, ( "use_srtp extension invalid profile" ) ); return; } buf[8] = mki_len & 0xFF; memcpy( &buf[9], ssl->dtls_srtp_info.mki_value, mki_len ); *olen = 9 + mki_len; } #endif /* MBEDTLS_SSL_DTLS_SRTP */ #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *p = ssl->out_msg + 4; unsigned char *cookie_len_byte; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) ); /* * struct { * ProtocolVersion server_version; * opaque cookie<0..2^8-1>; * } HelloVerifyRequest; */ /* The RFC is not clear on this point, but sending the actual negotiated * version looks like the most interoperable thing to do. */ mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, ssl->conf->transport, p ); MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 ); p += 2; /* If we get here, f_cookie_check is not null */ if( ssl->conf->f_cookie_write == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } /* Skip length byte until we know the length */ cookie_len_byte = p++; if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie, &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN, ssl->cli_id, ssl->cli_id_len ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret ); return( ret ); } *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) ); MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte ); ssl->out_msglen = p - ssl->out_msg; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST; ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT; if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); return( ret ); } #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret ); return( ret ); } #endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ static void ssl_handle_id_based_session_resumption( mbedtls_ssl_context *ssl ) { int ret; mbedtls_ssl_session session_tmp; mbedtls_ssl_session * const session = ssl->session_negotiate; /* Resume is 0 by default, see ssl_handshake_init(). * It may be already set to 1 by ssl_parse_session_ticket_ext(). */ if( ssl->handshake->resume == 1 ) return; if( session->id_len == 0 ) return; if( ssl->conf->f_get_cache == NULL ) return; #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ) return; #endif mbedtls_ssl_session_init( &session_tmp ); session_tmp.id_len = session->id_len; memcpy( session_tmp.id, session->id, session->id_len ); ret = ssl->conf->f_get_cache( ssl->conf->p_cache, &session_tmp ); if( ret != 0 ) goto exit; if( session->ciphersuite != session_tmp.ciphersuite || session->compression != session_tmp.compression ) { /* Mismatch between cached and negotiated session */ goto exit; } /* Move semantics */ mbedtls_ssl_session_free( session ); *session = session_tmp; memset( &session_tmp, 0, sizeof( session_tmp ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) ); ssl->handshake->resume = 1; exit: mbedtls_ssl_session_free( &session_tmp ); } static int ssl_write_server_hello( mbedtls_ssl_context *ssl ) { #if defined(MBEDTLS_HAVE_TIME) mbedtls_time_t t; #endif int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t olen, ext_len = 0, n; unsigned char *buf, *p; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) ); #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake->verify_cookie_len != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); return( ssl_write_hello_verify_request( ssl ) ); } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ if( ssl->conf->f_rng == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") ); return( MBEDTLS_ERR_SSL_NO_RNG ); } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 protocol version * 6 . 9 UNIX time() * 10 . 37 random bytes */ buf = ssl->out_msg; p = buf + 4; mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, ssl->conf->transport, p ); p += 2; MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]", buf[4], buf[5] ) ); #if defined(MBEDTLS_HAVE_TIME) t = mbedtls_time( NULL ); *p++ = (unsigned char)( t >> 24 ); *p++ = (unsigned char)( t >> 16 ); *p++ = (unsigned char)( t >> 8 ); *p++ = (unsigned char)( t ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %" MBEDTLS_PRINTF_LONGLONG, (long long) t ) ); #else if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 ) return( ret ); p += 4; #endif /* MBEDTLS_HAVE_TIME */ if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 ) return( ret ); p += 28; memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 ); MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 ); ssl_handle_id_based_session_resumption( ssl ); if( ssl->handshake->resume == 0 ) { /* * New session, create a new session id, * unless we're about to issue a session ticket */ ssl->state++; #if defined(MBEDTLS_HAVE_TIME) ssl->session_negotiate->start = mbedtls_time( NULL ); #endif #if defined(MBEDTLS_SSL_SESSION_TICKETS) if( ssl->handshake->new_session_ticket != 0 ) { ssl->session_negotiate->id_len = n = 0; memset( ssl->session_negotiate->id, 0, 32 ); } else #endif /* MBEDTLS_SSL_SESSION_TICKETS */ { ssl->session_negotiate->id_len = n = 32; if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id, n ) ) != 0 ) return( ret ); } } else { /* * Resuming a session */ n = ssl->session_negotiate->id_len; ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC; if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret ); return( ret ); } } /* * 38 . 38 session id length * 39 . 38+n session id * 39+n . 40+n chosen ciphersuite * 41+n . 41+n chosen compression alg. * 42+n . 43+n extensions length * 44+n . 43+n+m extensions */ *p++ = (unsigned char) ssl->session_negotiate->id_len; memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len ); p += ssl->session_negotiate->id_len; MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n ) ); MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed", ssl->handshake->resume ? "a" : "no" ) ); *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 ); *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite ); *p++ = (unsigned char)( ssl->session_negotiate->compression ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s", mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X", (unsigned int) ssl->session_negotiate->compression ) ); /* Do not write the extensions if the protocol is SSLv3 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) ) { #endif /* * First write extensions, then the total length */ ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) ssl_write_cid_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_SESSION_TICKETS) ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if ( mbedtls_ssl_ciphersuite_uses_ec( mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) ) { ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; } #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_ALPN) ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_DTLS_SRTP) ssl_write_use_srtp_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %" MBEDTLS_PRINTF_SIZET, ext_len ) ); if( ext_len > 0 ) { *p++ = MBEDTLS_CHAR_1( ext_len ); *p++ = MBEDTLS_CHAR_0( ext_len ); p += ext_len; } #if defined(MBEDTLS_SSL_PROTO_SSL3) } #endif ssl->out_msglen = p - buf; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO; ret = mbedtls_ssl_write_handshake_msg( ssl ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); return( ret ); } #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED) static int ssl_write_certificate_request( mbedtls_ssl_context *ssl ) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) ); ssl->state++; return( 0 ); } MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ static int ssl_write_certificate_request( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; uint16_t dn_size, total_dn_size; /* excluding length bytes */ size_t ct_len, sa_len; /* including length bytes */ unsigned char *buf, *p; const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; const mbedtls_x509_crt *crt; int authmode; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); ssl->state++; #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET ) authmode = ssl->handshake->sni_authmode; else #endif authmode = ssl->conf->authmode; if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) || authmode == MBEDTLS_SSL_VERIFY_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) ); return( 0 ); } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 4 cert type count * 5 .. m-1 cert types * m .. m+1 sig alg length (TLS 1.2 only) * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only) * n .. n+1 length of all DNs * n+2 .. n+3 length of DN 1 * n+4 .. ... Distinguished Name #1 * ... .. ... length of DN 2, etc. */ buf = ssl->out_msg; p = buf + 4; /* * Supported certificate types * * ClientCertificateType certificate_types<1..2^8-1>; * enum { (255) } ClientCertificateType; */ ct_len = 0; #if defined(MBEDTLS_RSA_C) p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN; #endif #if defined(MBEDTLS_ECDSA_C) p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN; #endif p[0] = (unsigned char) ct_len++; p += ct_len; sa_len = 0; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) /* * Add signature_algorithms for verify (TLS 1.2) * * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>; * * struct { * HashAlgorithm hash; * SignatureAlgorithm signature; * } SignatureAndHashAlgorithm; * * enum { (255) } HashAlgorithm; * enum { (255) } SignatureAlgorithm; */ if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { const int *cur; /* * Supported signature algorithms */ for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ ) { unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur ); if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) ) continue; #if defined(MBEDTLS_RSA_C) p[2 + sa_len++] = hash; p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA; #endif #if defined(MBEDTLS_ECDSA_C) p[2 + sa_len++] = hash; p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA; #endif } p[0] = (unsigned char)( sa_len >> 8 ); p[1] = (unsigned char)( sa_len ); sa_len += 2; p += sa_len; } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ /* * DistinguishedName certificate_authorities<0..2^16-1>; * opaque DistinguishedName<1..2^16-1>; */ p += 2; total_dn_size = 0; if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED ) { /* NOTE: If trusted certificates are provisioned * via a CA callback (configured through * `mbedtls_ssl_conf_ca_cb()`, then the * CertificateRequest is currently left empty. */ #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) if( ssl->handshake->sni_ca_chain != NULL ) crt = ssl->handshake->sni_ca_chain; else #endif crt = ssl->conf->ca_chain; while( crt != NULL && crt->version != 0 ) { /* It follows from RFC 5280 A.1 that this length * can be represented in at most 11 bits. */ dn_size = (uint16_t) crt->subject_raw.len; if( end < p || (size_t)( end - p ) < 2 + (size_t) dn_size ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) ); break; } *p++ = (unsigned char)( dn_size >> 8 ); *p++ = (unsigned char)( dn_size ); memcpy( p, crt->subject_raw.p, dn_size ); p += dn_size; MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size ); total_dn_size += 2 + dn_size; crt = crt->next; } } ssl->out_msglen = p - buf; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST; ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 ); ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size ); ret = mbedtls_ssl_write_handshake_msg( ssl ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) ); return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) ); return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH ); } if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx, mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ), MBEDTLS_ECDH_OURS ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret ); return( ret ); } return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \ defined(MBEDTLS_SSL_ASYNC_PRIVATE) static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl, size_t *signature_len ) { /* Append the signature to ssl->out_msg, leaving 2 bytes for the * signature length which will be added in ssl_write_server_key_exchange * after the call to ssl_prepare_server_key_exchange. * ssl_write_server_key_exchange also takes care of incrementing * ssl->out_msglen. */ unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2; size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN - sig_start ); int ret = ssl->conf->f_async_resume( ssl, sig_start, signature_len, sig_max_len ); if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ) { ssl->handshake->async_in_progress = 0; mbedtls_ssl_set_async_operation_data( ssl, NULL ); } MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret ); return( ret ); } #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && defined(MBEDTLS_SSL_ASYNC_PRIVATE) */ /* Prepare the ServerKeyExchange message, up to and including * calculating the signature if any, but excluding formatting the * signature and sending the message. */ static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl, size_t *signature_len ) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED) #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) unsigned char *dig_signed = NULL; #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */ (void) ciphersuite_info; /* unused in some configurations */ #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) (void) signature_len; #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */ /* * * Part 1: Provide key exchange parameters for chosen ciphersuite. * */ /* * - ECJPAKE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; ret = mbedtls_ecjpake_write_round_two( &ssl->handshake->ecjpake_ctx, ssl->out_msg + ssl->out_msglen, MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret ); return( ret ); } ssl->out_msglen += len; } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ /* * For (EC)DHE key exchanges with PSK, parameters are prefixed by support * identity hint (RFC 4279, Sec. 3). Until someone needs this feature, * we use empty support identity hints here. **/ #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ) { ssl->out_msg[ssl->out_msglen++] = 0x00; ssl->out_msg[ssl->out_msglen++] = 0x00; } #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ /* * - DHE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED) if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) ); return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); } /* * Ephemeral DH parameters: * * struct { * opaque dh_p<1..2^16-1>; * opaque dh_g<1..2^16-1>; * opaque dh_Ys<1..2^16-1>; * } ServerDHParams; */ if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx, &ssl->conf->dhm_P, &ssl->conf->dhm_G ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret ); return( ret ); } if( ( ret = mbedtls_dhm_make_params( &ssl->handshake->dhm_ctx, (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ), ssl->out_msg + ssl->out_msglen, &len, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret ); return( ret ); } #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) dig_signed = ssl->out_msg + ssl->out_msglen; #endif ssl->out_msglen += len; MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X ); MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P ); MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G ); MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX ); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */ /* * - ECDHE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED) if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) ) { /* * Ephemeral ECDH parameters: * * struct { * ECParameters curve_params; * ECPoint public; * } ServerECDHParams; */ const mbedtls_ecp_curve_info **curve = NULL; const mbedtls_ecp_group_id *gid; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; /* Match our preference list against the offered curves */ for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ ) for( curve = ssl->handshake->curves; *curve != NULL; curve++ ) if( (*curve)->grp_id == *gid ) goto curve_matching_done; curve_matching_done: if( curve == NULL || *curve == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) ); return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) ); if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx, (*curve)->grp_id ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret ); return( ret ); } if( ( ret = mbedtls_ecdh_make_params( &ssl->handshake->ecdh_ctx, &len, ssl->out_msg + ssl->out_msglen, MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret ); return( ret ); } #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) dig_signed = ssl->out_msg + ssl->out_msglen; #endif ssl->out_msglen += len; MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_Q ); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */ /* * * Part 2: For key exchanges involving the server signing the * exchange parameters, compute and add the signature here. * */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) ) { size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed; size_t hashlen = 0; unsigned char hash[MBEDTLS_MD_MAX_SIZE]; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; /* * 2.1: Choose hash algorithm: * A: For TLS 1.2, obey signature-hash-algorithm extension * to choose appropriate hash. * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1 * (RFC 4492, Sec. 5.4) * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3) */ mbedtls_md_type_t md_alg; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { /* A: For TLS 1.2, obey signature-hash-algorithm extension * (RFC 5246, Sec. 7.4.1.4.1). */ if( sig_alg == MBEDTLS_PK_NONE || ( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_alg ) ) == MBEDTLS_MD_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); /* (... because we choose a cipher suite * only if there is a matching hash.) */ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } } else #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ) { /* B: Default hash SHA1 */ md_alg = MBEDTLS_MD_SHA1; } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \ MBEDTLS_SSL_PROTO_TLS1_1 */ { /* C: MD5 + SHA1 */ md_alg = MBEDTLS_MD_NONE; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %u for signing", (unsigned) md_alg ) ); /* * 2.2: Compute the hash to be signed */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if( md_alg == MBEDTLS_MD_NONE ) { hashlen = 36; ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash, dig_signed, dig_signed_len ); if( ret != 0 ) return( ret ); } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \ MBEDTLS_SSL_PROTO_TLS1_1 */ #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_2) if( md_alg != MBEDTLS_MD_NONE ) { ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen, dig_signed, dig_signed_len, md_alg ); if( ret != 0 ) return( ret ); } else #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ MBEDTLS_SSL_PROTO_TLS1_2 */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen ); /* * 2.3: Compute and add the signature */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { /* * For TLS 1.2, we need to specify signature and hash algorithm * explicitly through a prefix to the signature. * * struct { * HashAlgorithm hash; * SignatureAlgorithm signature; * } SignatureAndHashAlgorithm; * * struct { * SignatureAndHashAlgorithm algorithm; * opaque signature<0..2^16-1>; * } DigitallySigned; * */ ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_hash_from_md_alg( md_alg ); ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_sig_from_pk_alg( sig_alg ); } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if( ssl->conf->f_async_sign_start != NULL ) { ret = ssl->conf->f_async_sign_start( ssl, mbedtls_ssl_own_cert( ssl ), md_alg, hash, hashlen ); switch( ret ) { case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH: /* act as if f_async_sign was null */ break; case 0: ssl->handshake->async_in_progress = 1; return( ssl_resume_server_key_exchange( ssl, signature_len ) ); case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS: ssl->handshake->async_in_progress = 1; return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ); default: MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret ); return( ret ); } } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if( mbedtls_ssl_own_key( ssl ) == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) ); return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* Append the signature to ssl->out_msg, leaving 2 bytes for the * signature length which will be added in ssl_write_server_key_exchange * after the call to ssl_prepare_server_key_exchange. * ssl_write_server_key_exchange also takes care of incrementing * ssl->out_msglen. */ if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ), md_alg, hash, hashlen, ssl->out_msg + ssl->out_msglen + 2, signature_len, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret ); return( ret ); } } #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ return( 0 ); } /* Prepare the ServerKeyExchange message and send it. For ciphersuites * that do not include a ServerKeyExchange message, do nothing. Either * way, if successful, move on to the next step in the SSL state * machine. */ static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t signature_len = 0; #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED) const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) ); #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED) /* Extract static ECDH parameters and abort if ServerKeyExchange * is not needed. */ if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) ) { /* For suites involving ECDH, extract DH parameters * from certificate at this point. */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED) if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) ) { ssl_get_ecdh_params_from_cert( ssl ); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */ /* Key exchanges not involving ephemeral keys don't use * ServerKeyExchange, so end here. */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) ); ssl->state++; return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \ defined(MBEDTLS_SSL_ASYNC_PRIVATE) /* If we have already prepared the message and there is an ongoing * signature operation, resume signing. */ if( ssl->handshake->async_in_progress != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) ); ret = ssl_resume_server_key_exchange( ssl, &signature_len ); } else #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && defined(MBEDTLS_SSL_ASYNC_PRIVATE) */ { /* ServerKeyExchange is needed. Prepare the message. */ ret = ssl_prepare_server_key_exchange( ssl, &signature_len ); } if( ret != 0 ) { /* If we're starting to write a new message, set ssl->out_msglen * to 0. But if we're resuming after an asynchronous message, * out_msglen is the amount of data written so far and mst be * preserved. */ if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ) MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) ); else ssl->out_msglen = 0; return( ret ); } /* If there is a signature, write its length. * ssl_prepare_server_key_exchange already wrote the signature * itself at its proper place in the output buffer. */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) if( signature_len != 0 ) { ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len >> 8 ); ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len ); MBEDTLS_SSL_DEBUG_BUF( 3, "my signature", ssl->out_msg + ssl->out_msglen, signature_len ); /* Skip over the already-written signature */ ssl->out_msglen += signature_len; } #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ /* Add header and send. */ ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE; ssl->state++; if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) ); return( 0 ); } static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) ); ssl->out_msglen = 4; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE; ssl->state++; #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) mbedtls_ssl_send_flight_completed( ssl ); #endif if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); return( ret ); } #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret ); return( ret ); } #endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) ); return( 0 ); } #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p, const unsigned char *end ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; size_t n; /* * Receive G^Y mod P, premaster = (G^Y)^X mod P */ if( *p + 2 > end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } n = ( (*p)[0] << 8 ) | (*p)[1]; *p += 2; if( *p + n > end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } *p += n; MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY ); return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl, unsigned char *peer_pms, size_t *peer_pmslen, size_t peer_pmssize ) { int ret = ssl->conf->f_async_resume( ssl, peer_pms, peer_pmslen, peer_pmssize ); if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ) { ssl->handshake->async_in_progress = 0; mbedtls_ssl_set_async_operation_data( ssl, NULL ); } MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret ); return( ret ); } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl, const unsigned char *p, const unsigned char *end, unsigned char *peer_pms, size_t *peer_pmslen, size_t peer_pmssize ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl ); mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk; size_t len = mbedtls_pk_get_len( public_key ); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) /* If we have already started decoding the message and there is an ongoing * decryption operation, resume signing. */ if( ssl->handshake->async_in_progress != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) ); return( ssl_resume_decrypt_pms( ssl, peer_pms, peer_pmslen, peer_pmssize ) ); } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ /* * Prepare to decrypt the premaster using own private RSA key */ #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_2) if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 ) { if ( p + 2 > end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( *p++ != MBEDTLS_CHAR_1( len ) || *p++ != MBEDTLS_CHAR_0( len ) ){ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } } #endif if( p + len != end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } /* * Decrypt the premaster secret */ #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if( ssl->conf->f_async_decrypt_start != NULL ) { ret = ssl->conf->f_async_decrypt_start( ssl, mbedtls_ssl_own_cert( ssl ), p, len ); switch( ret ) { case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH: /* act as if f_async_decrypt_start was null */ break; case 0: ssl->handshake->async_in_progress = 1; return( ssl_resume_decrypt_pms( ssl, peer_pms, peer_pmslen, peer_pmssize ) ); case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS: ssl->handshake->async_in_progress = 1; return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ); default: MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret ); return( ret ); } } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) ); return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ); } ret = mbedtls_pk_decrypt( private_key, p, len, peer_pms, peer_pmslen, peer_pmssize, ssl->conf->f_rng, ssl->conf->p_rng ); return( ret ); } static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl, const unsigned char *p, const unsigned char *end, size_t pms_offset ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *pms = ssl->handshake->premaster + pms_offset; unsigned char ver[2]; unsigned char fake_pms[48], peer_pms[48]; unsigned char mask; size_t i, peer_pmslen; unsigned int diff; /* In case of a failure in decryption, the decryption may write less than * 2 bytes of output, but we always read the first two bytes. It doesn't * matter in the end because diff will be nonzero in that case due to * ret being nonzero, and we only care whether diff is 0. * But do initialize peer_pms and peer_pmslen for robustness anyway. This * also makes memory analyzers happy (don't access uninitialized memory, * even if it's an unsigned char). */ peer_pms[0] = peer_pms[1] = ~0; peer_pmslen = 0; ret = ssl_decrypt_encrypted_pms( ssl, p, end, peer_pms, &peer_pmslen, sizeof( peer_pms ) ); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS ) return( ret ); #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ mbedtls_ssl_write_version( ssl->handshake->max_major_ver, ssl->handshake->max_minor_ver, ssl->conf->transport, ver ); /* Avoid data-dependent branches while checking for invalid * padding, to protect against timing-based Bleichenbacher-type * attacks. */ diff = (unsigned int) ret; diff |= peer_pmslen ^ 48; diff |= peer_pms[0] ^ ver[0]; diff |= peer_pms[1] ^ ver[1]; /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */ /* MSVC has a warning about unary minus on unsigned, but this is * well-defined and precisely what we want to do here */ #if defined(_MSC_VER) #pragma warning( push ) #pragma warning( disable : 4146 ) #endif mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) ); #if defined(_MSC_VER) #pragma warning( pop ) #endif /* * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding * must not cause the connection to end immediately; instead, send a * bad_record_mac later in the handshake. * To protect against timing-based variants of the attack, we must * not have any branch that depends on whether the decryption was * successful. In particular, always generate the fake premaster secret, * regardless of whether it will ultimately influence the output or not. */ ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) ); if( ret != 0 ) { /* It's ok to abort on an RNG failure, since this does not reveal * anything about the RSA decryption. */ return( ret ); } #if defined(MBEDTLS_SSL_DEBUG_ALL) if( diff != 0 ) MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); #endif if( sizeof( ssl->handshake->premaster ) < pms_offset || sizeof( ssl->handshake->premaster ) - pms_offset < 48 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } ssl->handshake->pmslen = 48; /* Set pms to either the true or the fake PMS, without * data-dependent branches. */ for( i = 0; i < ssl->handshake->pmslen; i++ ) pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] ); return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p, const unsigned char *end ) { int ret = 0; uint16_t n; if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) ); return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Receive client pre-shared key identity name */ if( end - *p < 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } n = ( (*p)[0] << 8 ) | (*p)[1]; *p += 2; if( n == 0 || n > end - *p ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->conf->f_psk != NULL ) { if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 ) ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; } else { /* Identity is not a big secret since clients send it in the clear, * but treat it carefully anyway, just in case */ if( n != ssl->conf->psk_identity_len || mbedtls_ssl_safer_memcmp( ssl->conf->psk_identity, *p, n ) != 0 ) { ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; } } if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY ) { MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY ); return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY ); } *p += n; return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */ static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; unsigned char *p, *end; ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) ); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \ ( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) ) if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) && ( ssl->handshake->async_in_progress != 0 ) ) { /* We've already read a record and there is an asynchronous * operation in progress to decrypt it. So skip reading the * record. */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) ); } else #endif if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ); end = ssl->in_msg + ssl->in_hslen; if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA ) { if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret ); return( ret ); } if( p != end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx, ssl->handshake->premaster, MBEDTLS_PREMASTER_SIZE, &ssl->handshake->pmslen, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS ); } MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K ); } else #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA ) { if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx, p, end - p) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_QP ); if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx, &ssl->handshake->pmslen, ssl->handshake->premaster, MBEDTLS_MPI_MAX_SIZE, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS ); } MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_Z ); } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( p != end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* For opaque PSKs, we perform the PSK-to-MS derivation atomatically * and skip the intermediate PMS. */ if( ssl_use_opaque_psk( ssl ) == 1 ) MBEDTLS_SSL_DEBUG_MSG( 1, ( "skip PMS generation for opaque PSK" ) ); else #endif /* MBEDTLS_USE_PSA_CRYPTO */ if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ) { #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if ( ssl->handshake->async_in_progress != 0 ) { /* There is an asynchronous operation in progress to * decrypt the encrypted premaster secret, so skip * directly to resuming this operation. */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) ); /* Update p to skip the PSK identity. ssl_parse_encrypted_pms * won't actually use it, but maintain p anyway for robustness. */ p += ssl->conf->psk_identity_len + 2; } else #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if( ssl_use_opaque_psk( ssl ) == 1 ) return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); #endif if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret ); return( ret ); } if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret ); return( ret ); } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if( ssl_use_opaque_psk( ssl ) == 1 ) return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); #endif if( p != end ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx, p, end - p ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if( ssl_use_opaque_psk( ssl ) == 1 ) return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); #endif MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_QP ); if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) { if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ) { ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx, p, end - p ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx, ssl->handshake->premaster, 32, &ssl->handshake->pmslen, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret ); return( ret ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret ); return( ret ); } ssl->state++; MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) ); return( 0 ); } #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED) static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl ) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) ); if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; size_t i, sig_len; unsigned char hash[48]; unsigned char *hash_start = hash; size_t hashlen; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) mbedtls_pk_type_t pk_alg; #endif mbedtls_md_type_t md_alg; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; mbedtls_pk_context * peer_pk; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) ); if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) if( ssl->session_negotiate->peer_cert == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ if( ssl->session_negotiate->peer_cert_digest == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ /* Read the message without adding it to the checksum */ ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ ); if( 0 != ret ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret ); return( ret ); } ssl->state++; /* Process the message contents */ if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE || ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } i = mbedtls_ssl_hs_hdr_len( ssl ); #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) peer_pk = &ssl->handshake->peer_pubkey; #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ if( ssl->session_negotiate->peer_cert == NULL ) { /* Should never happen */ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } peer_pk = &ssl->session_negotiate->peer_cert->pk; #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ /* * struct { * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only * opaque signature<0..2^16-1>; * } DigitallySigned; */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 ) { md_alg = MBEDTLS_MD_NONE; hashlen = 36; /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */ if( mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECDSA ) ) { hash_start += 16; hashlen -= 16; md_alg = MBEDTLS_MD_SHA1; } } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { if( i + 2 > ssl->in_hslen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* * Hash */ md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] ); if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg" " for verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } #if !defined(MBEDTLS_MD_SHA1) if( MBEDTLS_MD_SHA1 == md_alg ) hash_start += 16; #endif /* Info from md_alg will be used instead */ hashlen = 0; i++; /* * Signature */ if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) ) == MBEDTLS_PK_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg" " for verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* * Check the certificate's key type matches the signature alg */ if( !mbedtls_pk_can_do( peer_pk, pk_alg ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } i++; } else #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } if( i + 2 > ssl->in_hslen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1]; i += 2; if( i + sig_len != ssl->in_hslen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* Calculate hash and verify signature */ { size_t dummy_hlen; ssl->handshake->calc_verify( ssl, hash, &dummy_hlen ); } if( ( ret = mbedtls_pk_verify( peer_pk, md_alg, hash_start, hashlen, ssl->in_msg + i, sig_len ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret ); return( ret ); } mbedtls_ssl_update_handshake_status( ssl ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) ); return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t tlen; uint32_t lifetime; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) ); ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET; /* * struct { * uint32 ticket_lifetime_hint; * opaque ticket<0..2^16-1>; * } NewSessionTicket; * * 4 . 7 ticket_lifetime_hint (0 = unspecified) * 8 . 9 ticket_len (n) * 10 . 9+n ticket content */ if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket, ssl->session_negotiate, ssl->out_msg + 10, ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN, &tlen, &lifetime ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret ); tlen = 0; } ssl->out_msg[4] = MBEDTLS_CHAR_3( lifetime ); ssl->out_msg[5] = MBEDTLS_CHAR_2( lifetime ); ssl->out_msg[6] = MBEDTLS_CHAR_1( lifetime ); ssl->out_msg[7] = MBEDTLS_CHAR_0( lifetime ); ssl->out_msg[8] = MBEDTLS_CHAR_1( tlen ); ssl->out_msg[9] = MBEDTLS_CHAR_0( tlen ); ssl->out_msglen = 10 + tlen; /* * Morally equivalent to updating ssl->state, but NewSessionTicket and * ChangeCipherSpec share the same state. */ ssl->handshake->new_session_ticket = 0; if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ /* * SSL handshake -- server side -- single step */ int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl ) { int ret = 0; if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL ) return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) ); if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) return( ret ); #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING ) { if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) return( ret ); } #endif /* MBEDTLS_SSL_PROTO_DTLS */ switch( ssl->state ) { case MBEDTLS_SSL_HELLO_REQUEST: ssl->state = MBEDTLS_SSL_CLIENT_HELLO; break; /* * <== ClientHello */ case MBEDTLS_SSL_CLIENT_HELLO: ret = ssl_parse_client_hello( ssl ); break; #if defined(MBEDTLS_SSL_PROTO_DTLS) case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT: return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED ); #endif /* * ==> ServerHello * Certificate * ( ServerKeyExchange ) * ( CertificateRequest ) * ServerHelloDone */ case MBEDTLS_SSL_SERVER_HELLO: ret = ssl_write_server_hello( ssl ); break; case MBEDTLS_SSL_SERVER_CERTIFICATE: ret = mbedtls_ssl_write_certificate( ssl ); break; case MBEDTLS_SSL_SERVER_KEY_EXCHANGE: ret = ssl_write_server_key_exchange( ssl ); break; case MBEDTLS_SSL_CERTIFICATE_REQUEST: ret = ssl_write_certificate_request( ssl ); break; case MBEDTLS_SSL_SERVER_HELLO_DONE: ret = ssl_write_server_hello_done( ssl ); break; /* * <== ( Certificate/Alert ) * ClientKeyExchange * ( CertificateVerify ) * ChangeCipherSpec * Finished */ case MBEDTLS_SSL_CLIENT_CERTIFICATE: ret = mbedtls_ssl_parse_certificate( ssl ); break; case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE: ret = ssl_parse_client_key_exchange( ssl ); break; case MBEDTLS_SSL_CERTIFICATE_VERIFY: ret = ssl_parse_certificate_verify( ssl ); break; case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC: ret = mbedtls_ssl_parse_change_cipher_spec( ssl ); break; case MBEDTLS_SSL_CLIENT_FINISHED: ret = mbedtls_ssl_parse_finished( ssl ); break; /* * ==> ( NewSessionTicket ) * ChangeCipherSpec * Finished */ case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC: #if defined(MBEDTLS_SSL_SESSION_TICKETS) if( ssl->handshake->new_session_ticket != 0 ) ret = ssl_write_new_session_ticket( ssl ); else #endif ret = mbedtls_ssl_write_change_cipher_spec( ssl ); break; case MBEDTLS_SSL_SERVER_FINISHED: ret = mbedtls_ssl_write_finished( ssl ); break; case MBEDTLS_SSL_FLUSH_BUFFERS: MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) ); ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP; break; case MBEDTLS_SSL_HANDSHAKE_WRAPUP: mbedtls_ssl_handshake_wrapup( ssl ); break; default: MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) ); return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); } return( ret ); } #endif /* MBEDTLS_SSL_SRV_C */