/* * SSLv3/TLSv1 client-side functions * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * 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. * * This file is part of mbed TLS (https://tls.mbed.org) */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_SSL_CLI_C) #include "mbedtls/debug.h" #include "mbedtls/ssl.h" #include "mbedtls/ssl_internal.h" #include #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include #define mbedtls_calloc calloc #define mbedtls_free free #endif #include #if defined(MBEDTLS_HAVE_TIME) #include #endif #if defined(MBEDTLS_SSL_SESSION_TICKETS) /* Implementation that should never be optimized out by the compiler */ static void mbedtls_zeroize( void *v, size_t n ) { volatile unsigned char *p = v; while( n-- ) *p++ = 0; } #endif #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) static void ssl_write_hostname_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; size_t hostname_len; *olen = 0; if( ssl->hostname == NULL ) return; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding server name extension: %s", ssl->hostname ) ); hostname_len = strlen( ssl->hostname ); if( end < p || (size_t)( end - p ) < hostname_len + 9 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } /* * Sect. 3, RFC 6066 (TLS Extensions Definitions) * * In order to provide any of the server names, clients MAY include an * extension of type "server_name" in the (extended) client hello. The * "extension_data" field of this extension SHALL contain * "ServerNameList" where: * * struct { * NameType name_type; * select (name_type) { * case host_name: HostName; * } name; * } ServerName; * * enum { * host_name(0), (255) * } NameType; * * opaque HostName<1..2^16-1>; * * struct { * ServerName server_name_list<1..2^16-1> * } ServerNameList; * */ *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME ) & 0xFF ); *p++ = (unsigned char)( ( (hostname_len + 5) >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( (hostname_len + 5) ) & 0xFF ); *p++ = (unsigned char)( ( (hostname_len + 3) >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( (hostname_len + 3) ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME ) & 0xFF ); *p++ = (unsigned char)( ( hostname_len >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( hostname_len ) & 0xFF ); memcpy( p, ssl->hostname, hostname_len ); *olen = hostname_len + 9; } #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ #if defined(MBEDTLS_SSL_RENEGOTIATION) static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; if( ssl->renego_status != MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS ) return; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding renegotiation extension" ) ); if( end < p || (size_t)( end - p ) < 5 + ssl->verify_data_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } /* * Secure renegotiation */ *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF ); *p++ = 0x00; *p++ = ( ssl->verify_data_len + 1 ) & 0xFF; *p++ = ssl->verify_data_len & 0xFF; memcpy( p, ssl->own_verify_data, ssl->verify_data_len ); *olen = 5 + ssl->verify_data_len; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ /* * Only if we handle at least one key exchange that needs signatures. */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED) static void ssl_write_signature_algorithms_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; size_t sig_alg_len = 0; const int *md; #if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECDSA_C) unsigned char *sig_alg_list = buf + 6; #endif *olen = 0; if( ssl->conf->max_minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 ) return; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding signature_algorithms extension" ) ); for( md = ssl->conf->sig_hashes; *md != MBEDTLS_MD_NONE; md++ ) { #if defined(MBEDTLS_ECDSA_C) sig_alg_len += 2; #endif #if defined(MBEDTLS_RSA_C) sig_alg_len += 2; #endif } if( end < p || (size_t)( end - p ) < sig_alg_len + 6 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } /* * Prepare signature_algorithms extension (TLS 1.2) */ sig_alg_len = 0; for( md = ssl->conf->sig_hashes; *md != MBEDTLS_MD_NONE; md++ ) { #if defined(MBEDTLS_ECDSA_C) sig_alg_list[sig_alg_len++] = mbedtls_ssl_hash_from_md_alg( *md ); sig_alg_list[sig_alg_len++] = MBEDTLS_SSL_SIG_ECDSA; #endif #if defined(MBEDTLS_RSA_C) sig_alg_list[sig_alg_len++] = mbedtls_ssl_hash_from_md_alg( *md ); sig_alg_list[sig_alg_len++] = MBEDTLS_SSL_SIG_RSA; #endif } /* * enum { * none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5), * sha512(6), (255) * } HashAlgorithm; * * enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) } * SignatureAlgorithm; * * struct { * HashAlgorithm hash; * SignatureAlgorithm signature; * } SignatureAndHashAlgorithm; * * SignatureAndHashAlgorithm * supported_signature_algorithms<2..2^16-2>; */ *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG ) & 0xFF ); *p++ = (unsigned char)( ( ( sig_alg_len + 2 ) >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( ( sig_alg_len + 2 ) ) & 0xFF ); *p++ = (unsigned char)( ( sig_alg_len >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( sig_alg_len ) & 0xFF ); *olen = 6 + sig_alg_len; } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; unsigned char *elliptic_curve_list = p + 6; size_t elliptic_curve_len = 0; const mbedtls_ecp_curve_info *info; #if defined(MBEDTLS_ECP_C) const mbedtls_ecp_group_id *grp_id; #else ((void) ssl); #endif *olen = 0; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_elliptic_curves extension" ) ); #if defined(MBEDTLS_ECP_C) for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ ) { info = mbedtls_ecp_curve_info_from_grp_id( *grp_id ); #else for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ ) { #endif if( info == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid curve in ssl configuration" ) ); return; } elliptic_curve_len += 2; } if( end < p || (size_t)( end - p ) < 6 + elliptic_curve_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } elliptic_curve_len = 0; #if defined(MBEDTLS_ECP_C) for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ ) { info = mbedtls_ecp_curve_info_from_grp_id( *grp_id ); #else for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ ) { #endif elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8; elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF; } if( elliptic_curve_len == 0 ) return; *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES ) & 0xFF ); *p++ = (unsigned char)( ( ( elliptic_curve_len + 2 ) >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( ( elliptic_curve_len + 2 ) ) & 0xFF ); *p++ = (unsigned char)( ( ( elliptic_curve_len ) >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( ( elliptic_curve_len ) ) & 0xFF ); *olen = 6 + elliptic_curve_len; } static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_point_formats extension" ) ); if( end < p || (size_t)( end - p ) < 6 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF ); *p++ = 0x00; *p++ = 2; *p++ = 1; *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED; *olen = 6; } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */ #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; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; if( ssl->conf->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding max_fragment_length extension" ) ); if( end < p || (size_t)( end - p ) < 5 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF ); *p++ = 0x00; *p++ = 1; *p++ = ssl->conf->mfl_code; *olen = 5; } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #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; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding truncated_hmac extension" ) ); if( end < p || (size_t)( end - p ) < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *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_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 unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED || ssl->conf->max_minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding encrypt_then_mac " "extension" ) ); if( end < p || (size_t)( end - p ) < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF ); *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; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; *olen = 0; if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED || ssl->conf->max_minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding extended_master_secret " "extension" ) ); if( end < p || (size_t)( end - p ) < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF ); *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; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; size_t tlen = ssl->session_negotiate->ticket_len; *olen = 0; if( ssl->conf->session_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding session ticket extension" ) ); if( end < p || (size_t)( end - p ) < 4 + tlen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF ); *p++ = (unsigned char)( ( tlen >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( tlen ) & 0xFF ); *olen = 4; if( ssl->session_negotiate->ticket == NULL || tlen == 0 ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "sending session ticket of length %d", tlen ) ); memcpy( p, ssl->session_negotiate->ticket, tlen ); *olen += tlen; } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_ALPN) static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN; size_t alpnlen = 0; const char **cur; *olen = 0; if( ssl->conf->alpn_list == NULL ) { return; } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding alpn extension" ) ); for( cur = ssl->conf->alpn_list; *cur != NULL; cur++ ) alpnlen += (unsigned char)( strlen( *cur ) & 0xFF ) + 1; if( end < p || (size_t)( end - p ) < 6 + alpnlen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) ); return; } *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF ); /* * opaque ProtocolName<1..2^8-1>; * * struct { * ProtocolName protocol_name_list<2..2^16-1> * } ProtocolNameList; */ /* Skip writing extension and list length for now */ p += 4; for( cur = ssl->conf->alpn_list; *cur != NULL; cur++ ) { *p = (unsigned char)( strlen( *cur ) & 0xFF ); memcpy( p + 1, *cur, *p ); p += 1 + *p; } *olen = p - buf; /* List length = olen - 2 (ext_type) - 2 (ext_len) - 2 (list_len) */ buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF ); buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF ); /* Extension length = olen - 2 (ext_type) - 2 (ext_len) */ buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF ); buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF ); } #endif /* MBEDTLS_SSL_ALPN */ /* * Generate random bytes for ClientHello */ static int ssl_generate_random( mbedtls_ssl_context *ssl ) { int ret; unsigned char *p = ssl->handshake->randbytes; #if defined(MBEDTLS_HAVE_TIME) time_t t; #endif /* * When responding to a verify request, MUST reuse random (RFC 6347 4.2.1) */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake->verify_cookie != NULL ) { return( 0 ); } #endif #if defined(MBEDTLS_HAVE_TIME) t = 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, ( "client hello, current time: %lu", 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 ); return( 0 ); } /** * \brief Validate cipher suite against config in SSL context. * * \param suite_info cipher suite to validate * \param ssl SSL context * \param min_minor_ver Minimal minor version to accept a cipher suite * \param max_minor_ver Maximal minor version to accept a cipher suite * * \return 0 if valid, else 1 */ static int ssl_validate_ciphersuite( const mbedtls_ssl_ciphersuite_t * suite_info, const mbedtls_ssl_context * ssl, int min_minor_ver, int max_minor_ver ) { (void) ssl; if( suite_info == NULL ) return( 1 ); if( suite_info->min_minor_ver > max_minor_ver || suite_info->max_minor_ver < min_minor_ver ) return( 1 ); #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) ) return( 1 ); #endif #if defined(MBEDTLS_ARC4_C) if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED && suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 ) return( 1 ); #endif return( 0 ); } static int ssl_write_client_hello( mbedtls_ssl_context *ssl ) { int ret; size_t i, n, olen, ext_len = 0; unsigned char *buf; unsigned char *p, *q; unsigned char offer_compress; const int *ciphersuites; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) int uses_ec = 0; #endif MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) ); if( ssl->conf->f_rng == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") ); return( MBEDTLS_ERR_SSL_NO_RNG ); } #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE ) #endif { ssl->major_ver = ssl->conf->min_major_ver; ssl->minor_ver = ssl->conf->min_minor_ver; } if( ssl->conf->max_major_ver == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "configured max major version is invalid, " "consider using mbedtls_ssl_config_defaults()" ) ); return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 highest version supported * 6 . 9 current UNIX time * 10 . 37 random bytes */ buf = ssl->out_msg; p = buf + 4; mbedtls_ssl_write_version( ssl->conf->max_major_ver, ssl->conf->max_minor_ver, ssl->conf->transport, p ); p += 2; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, max version: [%d:%d]", buf[4], buf[5] ) ); if( ( ret = ssl_generate_random( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "ssl_generate_random", ret ); return( ret ); } memcpy( p, ssl->handshake->randbytes, 32 ); MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", p, 32 ); p += 32; /* * 38 . 38 session id length * 39 . 39+n session id * 39+n . 39+n DTLS only: cookie length (1 byte) * 40+n . .. DTSL only: cookie * .. . .. ciphersuitelist length (2 bytes) * .. . .. ciphersuitelist * .. . .. compression methods length (1 byte) * .. . .. compression methods * .. . .. extensions length (2 bytes) * .. . .. extensions */ n = ssl->session_negotiate->id_len; if( n < 16 || n > 32 || #if defined(MBEDTLS_SSL_RENEGOTIATION) ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE || #endif ssl->handshake->resume == 0 ) { n = 0; } #if defined(MBEDTLS_SSL_SESSION_TICKETS) /* * RFC 5077 section 3.4: "When presenting a ticket, the client MAY * generate and include a Session ID in the TLS ClientHello." */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE ) #endif { if( ssl->session_negotiate->ticket != NULL && ssl->session_negotiate->ticket_len != 0 ) { ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id, 32 ); if( ret != 0 ) return( ret ); ssl->session_negotiate->id_len = n = 32; } } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ *p++ = (unsigned char) n; for( i = 0; i < n; i++ ) *p++ = ssl->session_negotiate->id[i]; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, session id len.: %d", n ) ); MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 39, n ); /* * DTLS cookie */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { if( ssl->handshake->verify_cookie == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "no verify cookie to send" ) ); *p++ = 0; } else { MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie", ssl->handshake->verify_cookie, ssl->handshake->verify_cookie_len ); *p++ = ssl->handshake->verify_cookie_len; memcpy( p, ssl->handshake->verify_cookie, ssl->handshake->verify_cookie_len ); p += ssl->handshake->verify_cookie_len; } } #endif /* * Ciphersuite list */ ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver]; /* Skip writing ciphersuite length for now */ n = 0; q = p; p += 2; for( i = 0; ciphersuites[i] != 0; i++ ) { ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuites[i] ); if( ssl_validate_ciphersuite( ciphersuite_info, ssl, ssl->conf->min_minor_ver, ssl->conf->max_minor_ver ) != 0 ) continue; MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %2d", ciphersuites[i] ) ); #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) uses_ec |= mbedtls_ssl_ciphersuite_uses_ec( ciphersuite_info ); #endif n++; *p++ = (unsigned char)( ciphersuites[i] >> 8 ); *p++ = (unsigned char)( ciphersuites[i] ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, got %d ciphersuites (excluding SCSVs)", n ) ); /* * Add TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE ) #endif { MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding EMPTY_RENEGOTIATION_INFO_SCSV" ) ); *p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO >> 8 ); *p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO ); n++; } /* Some versions of OpenSSL don't handle it correctly if not at end */ #if defined(MBEDTLS_SSL_FALLBACK_SCSV) if( ssl->conf->fallback == MBEDTLS_SSL_IS_FALLBACK ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding FALLBACK_SCSV" ) ); *p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ); *p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ); n++; } #endif *q++ = (unsigned char)( n >> 7 ); *q++ = (unsigned char)( n << 1 ); #if defined(MBEDTLS_ZLIB_SUPPORT) offer_compress = 1; #else offer_compress = 0; #endif /* * We don't support compression with DTLS right now: is many records come * in the same datagram, uncompressing one could overwrite the next one. * We don't want to add complexity for handling that case unless there is * an actual need for it. */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) offer_compress = 0; #endif if( offer_compress ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 2 ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d %d", MBEDTLS_SSL_COMPRESS_DEFLATE, MBEDTLS_SSL_COMPRESS_NULL ) ); *p++ = 2; *p++ = MBEDTLS_SSL_COMPRESS_DEFLATE; *p++ = MBEDTLS_SSL_COMPRESS_NULL; } else { MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 1 ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d", MBEDTLS_SSL_COMPRESS_NULL ) ); *p++ = 1; *p++ = MBEDTLS_SSL_COMPRESS_NULL; } // First write extensions, then the total length // #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) ssl_write_hostname_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_RENEGOTIATION) ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED) ssl_write_signature_algorithms_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) if( uses_ec ) { ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; } #endif #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_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_ALPN) ssl_write_alpn_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 /* olen unused if all extensions are disabled */ ((void) olen); MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %d", ext_len ) ); if( ext_len > 0 ) { *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( ext_len ) & 0xFF ); p += ext_len; } ssl->out_msglen = p - buf; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_CLIENT_HELLO; 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_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) ); return( 0 ); } static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret; #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 * 2 || buf[0] != ssl->verify_data_len * 2 || mbedtls_ssl_safer_memcmp( buf + 1, ssl->own_verify_data, ssl->verify_data_len ) != 0 || mbedtls_ssl_safer_memcmp( buf + 1 + ssl->verify_data_len, ssl->peer_verify_data, ssl->verify_data_len ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) ); if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } } else #endif /* MBEDTLS_SSL_RENEGOTIATION */ { if( len != 1 || buf[0] != 0x00 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) ); if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; } return( 0 ); } #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 ) { /* * server should use the extension only if we did, * and if so the server's value should match ours (and len is always 1) */ if( ssl->conf->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE || len != 1 || buf[0] != ssl->conf->mfl_code ) { return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } return( 0 ); } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #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( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED || len != 0 ) { return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ((void) buf); 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( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED || ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 || len != 0 ) { return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ((void) buf); 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( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED || ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 || len != 0 ) { return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ((void) buf); 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, const unsigned char *buf, size_t len ) { if( ssl->conf->session_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED || len != 0 ) { return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ((void) buf); ssl->handshake->new_session_ticket = 1; return( 0 ); } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) static int ssl_parse_supported_point_formats_ext( 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 server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_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 ) { ssl->handshake->ecdh_ctx.point_format = p[0]; MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) ); return( 0 ); } list_size--; p++; } MBEDTLS_SSL_DEBUG_MSG( 1, ( "no point format in common" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */ #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, name_len; const char **p; /* If we didn't send it, the server shouldn't send it */ if( ssl->conf->alpn_list == NULL ) return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); /* * opaque ProtocolName<1..2^8-1>; * * struct { * ProtocolName protocol_name_list<2..2^16-1> * } ProtocolNameList; * * the "ProtocolNameList" MUST contain exactly one "ProtocolName" */ /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */ if( len < 4 ) return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); list_len = ( buf[0] << 8 ) | buf[1]; if( list_len != len - 2 ) return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); name_len = buf[2]; if( name_len != list_len - 1 ) return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); /* Check that the server chosen protocol was in our list and save it */ for( p = ssl->conf->alpn_list; *p != NULL; p++ ) { if( name_len == strlen( *p ) && memcmp( buf + 3, *p, name_len ) == 0 ) { ssl->alpn_chosen = *p; return( 0 ); } } return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } #endif /* MBEDTLS_SSL_ALPN */ /* * Parse HelloVerifyRequest. Only called after verifying the HS type. */ #if defined(MBEDTLS_SSL_PROTO_DTLS) static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl ) { const unsigned char *p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ); int major_ver, minor_ver; unsigned char cookie_len; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse hello verify request" ) ); /* * struct { * ProtocolVersion server_version; * opaque cookie<0..2^8-1>; * } HelloVerifyRequest; */ MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 ); mbedtls_ssl_read_version( &major_ver, &minor_ver, ssl->conf->transport, p ); p += 2; /* * Since the RFC is not clear on this point, accept DTLS 1.0 (TLS 1.1) * even is lower than our min version. */ if( major_ver < MBEDTLS_SSL_MAJOR_VERSION_3 || minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 || major_ver > ssl->conf->max_major_ver || minor_ver > ssl->conf->max_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server version" ) ); 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 ); } cookie_len = *p++; MBEDTLS_SSL_DEBUG_BUF( 3, "cookie", p, cookie_len ); if( ( ssl->in_msg + ssl->in_msglen ) - p < cookie_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "cookie length does not match incoming message size" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } mbedtls_free( ssl->handshake->verify_cookie ); ssl->handshake->verify_cookie = mbedtls_calloc( 1, cookie_len ); if( ssl->handshake->verify_cookie == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc failed (%d bytes)", cookie_len ) ); return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); } memcpy( ssl->handshake->verify_cookie, p, cookie_len ); ssl->handshake->verify_cookie_len = cookie_len; /* Start over at ClientHello */ ssl->state = MBEDTLS_SSL_CLIENT_HELLO; mbedtls_ssl_reset_checksum( ssl ); mbedtls_ssl_recv_flight_completed( ssl ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse hello verify request" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_PROTO_DTLS */ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl ) { int ret, i; size_t n; size_t ext_len; unsigned char *buf, *ext; unsigned char comp; #if defined(MBEDTLS_ZLIB_SUPPORT) int accept_comp; #endif #if defined(MBEDTLS_SSL_RENEGOTIATION) int renegotiation_info_seen = 0; #endif int handshake_failure = 0; const mbedtls_ssl_ciphersuite_t *suite_info; #if defined(MBEDTLS_DEBUG_C) uint32_t t; #endif MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello" ) ); buf = ssl->in_msg; if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { #if defined(MBEDTLS_SSL_RENEGOTIATION) if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS ) { ssl->renego_records_seen++; if( ssl->conf->renego_max_records >= 0 && ssl->renego_records_seen > ssl->conf->renego_max_records ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation requested, " "but not honored by server" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-handshake message during renego" ) ); ssl->keep_current_message = 1; return( MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO ); } #endif /* MBEDTLS_SSL_RENEGOTIATION */ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { if( buf[0] == MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "received hello verify request" ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse server hello" ) ); return( ssl_parse_hello_verify_request( ssl ) ); } else { /* We made it through the verification process */ mbedtls_free( ssl->handshake->verify_cookie ); ssl->handshake->verify_cookie = NULL; ssl->handshake->verify_cookie_len = 0; } } #endif /* MBEDTLS_SSL_PROTO_DTLS */ if( ssl->in_hslen < 38 + mbedtls_ssl_hs_hdr_len( ssl ) || buf[0] != MBEDTLS_SSL_HS_SERVER_HELLO ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } /* * 0 . 1 server_version * 2 . 33 random (maybe including 4 bytes of Unix time) * 34 . 34 session_id length = n * 35 . 34+n session_id * 35+n . 36+n cipher_suite * 37+n . 37+n compression_method * * 38+n . 39+n extensions length (optional) * 40+n . .. extensions */ buf += mbedtls_ssl_hs_hdr_len( ssl ); MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, version", buf + 0, 2 ); mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver, ssl->conf->transport, buf + 0 ); if( ssl->major_ver < ssl->conf->min_major_ver || ssl->minor_ver < ssl->conf->min_minor_ver || ssl->major_ver > ssl->conf->max_major_ver || ssl->minor_ver > ssl->conf->max_minor_ver ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server version out of bounds - " " min: [%d:%d], server: [%d:%d], max: [%d:%d]", ssl->conf->min_major_ver, ssl->conf->min_minor_ver, ssl->major_ver, ssl->minor_ver, ssl->conf->max_major_ver, ssl->conf->max_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 defined(MBEDTLS_DEBUG_C) t = ( (uint32_t) buf[2] << 24 ) | ( (uint32_t) buf[3] << 16 ) | ( (uint32_t) buf[4] << 8 ) | ( (uint32_t) buf[5] ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) ); #endif memcpy( ssl->handshake->randbytes + 32, buf + 2, 32 ); n = buf[34]; MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 2, 32 ); if( n > 32 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } if( ssl->in_hslen > mbedtls_ssl_hs_hdr_len( ssl ) + 39 + n ) { ext_len = ( ( buf[38 + n] << 8 ) | ( buf[39 + n] ) ); if( ( ext_len > 0 && ext_len < 4 ) || ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) + 40 + n + ext_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } } else if( ssl->in_hslen == mbedtls_ssl_hs_hdr_len( ssl ) + 38 + n ) { ext_len = 0; } else { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } /* ciphersuite (used later) */ i = ( buf[35 + n] << 8 ) | buf[36 + n]; /* * Read and check compression */ comp = buf[37 + n]; #if defined(MBEDTLS_ZLIB_SUPPORT) /* See comments in ssl_write_client_hello() */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) accept_comp = 0; else #endif accept_comp = 1; if( comp != MBEDTLS_SSL_COMPRESS_NULL && ( comp != MBEDTLS_SSL_COMPRESS_DEFLATE || accept_comp == 0 ) ) #else /* MBEDTLS_ZLIB_SUPPORT */ if( comp != MBEDTLS_SSL_COMPRESS_NULL ) #endif/* MBEDTLS_ZLIB_SUPPORT */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server hello, bad compression: %d", comp ) ); return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); } /* * Initialize update checksum functions */ ssl->transform_negotiate->ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( i ); if( ssl->transform_negotiate->ciphersuite_info == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "ciphersuite info for %04x not found", i ) ); return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); } mbedtls_ssl_optimize_checksum( ssl, ssl->transform_negotiate->ciphersuite_info ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) ); MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 35, n ); /* * Check if the session can be resumed */ if( ssl->handshake->resume == 0 || n == 0 || #if defined(MBEDTLS_SSL_RENEGOTIATION) ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE || #endif ssl->session_negotiate->ciphersuite != i || ssl->session_negotiate->compression != comp || ssl->session_negotiate->id_len != n || memcmp( ssl->session_negotiate->id, buf + 35, n ) != 0 ) { ssl->state++; ssl->handshake->resume = 0; #if defined(MBEDTLS_HAVE_TIME) ssl->session_negotiate->start = time( NULL ); #endif ssl->session_negotiate->ciphersuite = i; ssl->session_negotiate->compression = comp; ssl->session_negotiate->id_len = n; memcpy( ssl->session_negotiate->id, buf + 35, n ); } else { 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 ); } } MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed", ssl->handshake->resume ? "a" : "no" ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %d", i ) ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", buf[37 + n] ) ); /* * Perform cipher suite validation in same way as in ssl_write_client_hello. */ i = 0; while( 1 ) { if( ssl->conf->ciphersuite_list[ssl->minor_ver][i] == 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } if( ssl->conf->ciphersuite_list[ssl->minor_ver][i++] == ssl->session_negotiate->ciphersuite ) { break; } } suite_info = mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ); if( ssl_validate_ciphersuite( suite_info, ssl, ssl->minor_ver, ssl->minor_ver ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s", suite_info->name ) ); if( comp != MBEDTLS_SSL_COMPRESS_NULL #if defined(MBEDTLS_ZLIB_SUPPORT) && comp != MBEDTLS_SSL_COMPRESS_DEFLATE #endif ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } ssl->session_negotiate->compression = comp; ext = buf + 40 + n; MBEDTLS_SSL_DEBUG_MSG( 2, ( "server hello, total extension length: %d", ext_len ) ); while( ext_len ) { unsigned int ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) ); unsigned int ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) ); if( ext_size + 4 > ext_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } switch( ext_id ) { case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) ); #if defined(MBEDTLS_SSL_RENEGOTIATION) renegotiation_info_seen = 1; #endif if( ( ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size ) ) != 0 ) return( ret ); break; #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max_fragment_length extension" ) ); if( ( ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size ) ) != 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" ) ); if( ( ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size ) ) != 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" ) ); if( ( ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size ) ) != 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" ) ); if( ( ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size ) ) != 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" ) ); if( ( ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size ) ) != 0 ) { return( ret ); } break; #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported_point_formats extension" ) ); if( ( ret = ssl_parse_supported_point_formats_ext( ssl, ext + 4, ext_size ) ) != 0 ) { return( ret ); } break; #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */ #if defined(MBEDTLS_SSL_ALPN) case MBEDTLS_TLS_EXT_ALPN: MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) ); if( ( ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size ) ) != 0 ) return( ret ); break; #endif /* MBEDTLS_SSL_ALPN */ default: MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)", ext_id ) ); } ext_len -= 4 + ext_size; ext += 4 + ext_size; if( ext_len > 0 && ext_len < 4 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } } /* * 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" ) ); 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 ) { if( ( ret = mbedtls_ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse server hello" ) ); return( 0 ); } #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) static int ssl_parse_server_dh_params( mbedtls_ssl_context *ssl, unsigned char **p, unsigned char *end ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; /* * 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_read_params( &ssl->handshake->dhm_ctx, p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 2, ( "mbedtls_dhm_read_params" ), ret ); return( ret ); } if( ssl->handshake->dhm_ctx.len * 8 < ssl->conf->dhm_min_bitlen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "DHM prime too short: %d < %d", ssl->handshake->dhm_ctx.len * 8, ssl->conf->dhm_min_bitlen ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } 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: 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_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) static int ssl_check_server_ecdh_params( const mbedtls_ssl_context *ssl ) { const mbedtls_ecp_curve_info *curve_info; curve_info = mbedtls_ecp_curve_info_from_grp_id( ssl->handshake->ecdh_ctx.grp.id ); if( curve_info == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDH curve: %s", curve_info->name ) ); #if defined(MBEDTLS_ECP_C) if( mbedtls_ssl_check_curve( ssl, ssl->handshake->ecdh_ctx.grp.id ) != 0 ) #else if( ssl->handshake->ecdh_ctx.grp.nbits < 163 || ssl->handshake->ecdh_ctx.grp.nbits > 521 ) #endif return( -1 ); MBEDTLS_SSL_DEBUG_ECP( 3, "ECDH: Qp", &ssl->handshake->ecdh_ctx.Qp ); return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) static int ssl_parse_server_ecdh_params( mbedtls_ssl_context *ssl, unsigned char **p, unsigned char *end ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; /* * Ephemeral ECDH parameters: * * struct { * ECParameters curve_params; * ECPoint public; * } ServerECDHParams; */ if( ( ret = mbedtls_ecdh_read_params( &ssl->handshake->ecdh_ctx, (const unsigned char **) p, end ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_read_params" ), ret ); return( ret ); } if( ssl_check_server_ecdh_params( ssl ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message (ECDHE curve)" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED) static int ssl_parse_server_psk_hint( mbedtls_ssl_context *ssl, unsigned char **p, unsigned char *end ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; size_t len; ((void) ssl); /* * PSK parameters: * * opaque psk_identity_hint<0..2^16-1>; */ if( end - (*p) < 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message " "(psk_identity_hint length)" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } len = (*p)[0] << 8 | (*p)[1]; *p += 2; if( end - (*p) < (int) len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message " "(psk_identity_hint length)" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } *p += len; ret = 0; return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) /* * Generate a pre-master secret and encrypt it with the server's RSA key */ static int ssl_write_encrypted_pms( mbedtls_ssl_context *ssl, size_t offset, size_t *olen, size_t pms_offset ) { int ret; size_t len_bytes = ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ? 0 : 2; unsigned char *p = ssl->handshake->premaster + pms_offset; if( offset + len_bytes > MBEDTLS_SSL_MAX_CONTENT_LEN ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small for encrypted pms" ) ); return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); } /* * Generate (part of) the pre-master as * struct { * ProtocolVersion client_version; * opaque random[46]; * } PreMasterSecret; */ mbedtls_ssl_write_version( ssl->conf->max_major_ver, ssl->conf->max_minor_ver, ssl->conf->transport, p ); if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p + 2, 46 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret ); return( ret ); } ssl->handshake->pmslen = 48; if( ssl->session_negotiate->peer_cert == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } /* * Now write it out, encrypted */ if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, MBEDTLS_PK_RSA ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "certificate key type mismatch" ) ); return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH ); } if( ( ret = mbedtls_pk_encrypt( &ssl->session_negotiate->peer_cert->pk, p, ssl->handshake->pmslen, ssl->out_msg + offset + len_bytes, olen, MBEDTLS_SSL_MAX_CONTENT_LEN - offset - len_bytes, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_rsa_pkcs1_encrypt", ret ); return( ret ); } #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_2) if( len_bytes == 2 ) { ssl->out_msg[offset+0] = (unsigned char)( *olen >> 8 ); ssl->out_msg[offset+1] = (unsigned char)( *olen ); *olen += 2; } #endif return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) static int ssl_parse_signature_algorithm( mbedtls_ssl_context *ssl, unsigned char **p, unsigned char *end, mbedtls_md_type_t *md_alg, mbedtls_pk_type_t *pk_alg ) { ((void) ssl); *md_alg = MBEDTLS_MD_NONE; *pk_alg = MBEDTLS_PK_NONE; /* Only in TLS 1.2 */ if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 ) { return( 0 ); } if( (*p) + 2 > end ) return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); /* * Get hash algorithm */ if( ( *md_alg = mbedtls_ssl_md_alg_from_hash( (*p)[0] ) ) == MBEDTLS_MD_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "Server used unsupported " "HashAlgorithm %d", *(p)[0] ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } /* * Get signature algorithm */ if( ( *pk_alg = mbedtls_ssl_pk_alg_from_sig( (*p)[1] ) ) == MBEDTLS_PK_NONE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server used unsupported " "SignatureAlgorithm %d", (*p)[1] ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } /* * Check if the hash is acceptable */ if( mbedtls_ssl_check_sig_hash( ssl, *md_alg ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server used HashAlgorithm %d that was not offered", *(p)[0] ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "Server used SignatureAlgorithm %d", (*p)[1] ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "Server used HashAlgorithm %d", (*p)[0] ) ); *p += 2; return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */ #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ #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; const mbedtls_ecp_keypair *peer_key; if( ssl->session_negotiate->peer_cert == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, MBEDTLS_PK_ECKEY ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) ); return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH ); } peer_key = mbedtls_pk_ec( ssl->session_negotiate->peer_cert->pk ); if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx, peer_key, MBEDTLS_ECDH_THEIRS ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret ); return( ret ); } if( ssl_check_server_ecdh_params( ssl ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server certificate (ECDH curve)" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ); } return( ret ); } #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl ) { int ret; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; unsigned char *p = NULL, *end = NULL; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server key exchange" ) ); #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse server key exchange" ) ); ssl->state++; return( 0 ); } ((void) p); ((void) end); #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA ) { if( ( ret = ssl_get_ecdh_params_from_cert( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "ssl_get_ecdh_params_from_cert", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse server key exchange" ) ); ssl->state++; return( 0 ); } ((void) p); ((void) end); #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } /* * ServerKeyExchange may be skipped with PSK and RSA-PSK when the server * doesn't use a psk_identity_hint */ if( ssl->in_msg[0] != MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE ) { if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ) { /* Current message is probably either * CertificateRequest or ServerHelloDone */ ssl->keep_current_message = 1; goto exit; } MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key exchange message must " "not be skipped" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ); end = ssl->in_msg + ssl->in_hslen; MBEDTLS_SSL_DEBUG_BUF( 3, "server key exchange", p, end - p ); #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ) { if( ssl_parse_server_psk_hint( ssl, &p, end ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } } /* FALLTROUGH */ #endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ) ; /* nothing more to do */ else #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ) { if( ssl_parse_server_dh_params( ssl, &p, end ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ) { if( ssl_parse_server_ecdh_params( ssl, &p, end ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } #if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) ) { size_t sig_len, hashlen; unsigned char hash[64]; mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE; mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE; unsigned char *params = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ); size_t params_len = p - params; /* * Handle the digitally-signed structure */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { if( ssl_parse_signature_algorithm( ssl, &p, end, &md_alg, &pk_alg ) != 0 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } if( pk_alg != mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } } 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( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 ) { pk_alg = mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); /* Default hash for ECDSA is SHA-1 */ if( pk_alg == MBEDTLS_PK_ECDSA && md_alg == MBEDTLS_MD_NONE ) md_alg = MBEDTLS_MD_SHA1; } else #endif { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } /* * Read signature */ if( p > end - 2 ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } sig_len = ( p[0] << 8 ) | p[1]; p += 2; if( p != end - sig_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); } MBEDTLS_SSL_DEBUG_BUF( 3, "signature", p, sig_len ); /* * Compute the hash that has been signed */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if( md_alg == MBEDTLS_MD_NONE ) { mbedtls_md5_context mbedtls_md5; mbedtls_sha1_context mbedtls_sha1; mbedtls_md5_init( &mbedtls_md5 ); mbedtls_sha1_init( &mbedtls_sha1 ); hashlen = 36; /* * digitally-signed struct { * opaque md5_hash[16]; * opaque sha_hash[20]; * }; * * md5_hash * MD5(ClientHello.random + ServerHello.random * + ServerParams); * sha_hash * SHA(ClientHello.random + ServerHello.random * + ServerParams); */ mbedtls_md5_starts( &mbedtls_md5 ); mbedtls_md5_update( &mbedtls_md5, ssl->handshake->randbytes, 64 ); mbedtls_md5_update( &mbedtls_md5, params, params_len ); mbedtls_md5_finish( &mbedtls_md5, hash ); mbedtls_sha1_starts( &mbedtls_sha1 ); mbedtls_sha1_update( &mbedtls_sha1, ssl->handshake->randbytes, 64 ); mbedtls_sha1_update( &mbedtls_sha1, params, params_len ); mbedtls_sha1_finish( &mbedtls_sha1, hash + 16 ); mbedtls_md5_free( &mbedtls_md5 ); mbedtls_sha1_free( &mbedtls_sha1 ); } 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 ) { mbedtls_md_context_t ctx; mbedtls_md_init( &ctx ); /* Info from md_alg will be used instead */ hashlen = 0; /* * digitally-signed struct { * opaque client_random[32]; * opaque server_random[32]; * ServerDHParams params; * }; */ if( ( ret = mbedtls_md_setup( &ctx, mbedtls_md_info_from_type( md_alg ), 0 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret ); return( ret ); } mbedtls_md_starts( &ctx ); mbedtls_md_update( &ctx, ssl->handshake->randbytes, 64 ); mbedtls_md_update( &ctx, params, params_len ); mbedtls_md_finish( &ctx, hash ); mbedtls_md_free( &ctx ); } 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 != 0 ? hashlen : (unsigned int) ( mbedtls_md_get_size( mbedtls_md_info_from_type( md_alg ) ) ) ); if( ssl->session_negotiate->peer_cert == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "certificate required" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } /* * Verify signature */ if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) ); return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH ); } if( ( ret = mbedtls_pk_verify( &ssl->session_negotiate->peer_cert->pk, md_alg, hash, hashlen, p, sig_len ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret ); return( ret ); } } #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */ exit: ssl->state++; MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse server key exchange" ) ); return( 0 ); } #if !defined(MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED) static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl ) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate request" ) ); if( ! mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse 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_parse_certificate_request( mbedtls_ssl_context *ssl ) { int ret; unsigned char *buf, *p; size_t n = 0; size_t cert_type_len = 0, dn_len = 0; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate request" ) ); if( ! mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate request" ) ); ssl->state++; return( 0 ); } if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } ssl->state++; ssl->client_auth = ( ssl->in_msg[0] == MBEDTLS_SSL_HS_CERTIFICATE_REQUEST ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "got %s certificate request", ssl->client_auth ? "a" : "no" ) ); if( ssl->client_auth == 0 ) { /* Current message is probably the ServerHelloDone */ ssl->keep_current_message = 1; goto exit; } /* * struct { * ClientCertificateType certificate_types<1..2^8-1>; * SignatureAndHashAlgorithm * supported_signature_algorithms<2^16-1>; -- TLS 1.2 only * DistinguishedName certificate_authorities<0..2^16-1>; * } CertificateRequest; */ buf = ssl->in_msg; // Retrieve cert types // if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST ); } cert_type_len = buf[mbedtls_ssl_hs_hdr_len( ssl )]; n = cert_type_len; /* * In the subsequent code there are two paths that read from buf: * * the length of the signature algorithms field (if minor version of * SSL is 3), * * distinguished name length otherwise. * Both reach at most the index: * ...hdr_len + 2 + n, * therefore the buffer length at this point must be greater than that * regardless of the actual code path. */ if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST ); } p = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 1; while( cert_type_len > 0 ) { #if defined(MBEDTLS_RSA_C) if( *p == MBEDTLS_SSL_CERT_TYPE_RSA_SIGN && mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_RSA ) ) { ssl->handshake->cert_type = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN; break; } else #endif #if defined(MBEDTLS_ECDSA_C) if( *p == MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN && mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECDSA ) ) { ssl->handshake->cert_type = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN; break; } else #endif { ; /* Unsupported cert type, ignore */ } cert_type_len--; p++; } #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 ) { /* Ignored, see comments about hash in write_certificate_verify */ size_t sig_alg_len = ( ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 1 + n] << 8 ) | ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n] ) ); #if defined(MBEDTLS_DEBUG_C) unsigned char* sig_alg; size_t i; #endif /* * The furthest access in buf is in the loop few lines below: * sig_alg[i + 1], * where: * sig_alg = buf + ...hdr_len + 3 + n, * max(i) = sig_alg_len - 1. * Therefore the furthest access is: * buf[...hdr_len + 3 + n + sig_alg_len - 1 + 1], * which reduces to: * buf[...hdr_len + 3 + n + sig_alg_len], * which is one less than we need the buf to be. */ if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n + sig_alg_len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) ); mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST ); } #if defined(MBEDTLS_DEBUG_C) sig_alg = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n; for( i = 0; i < sig_alg_len; i += 2 ) { MBEDTLS_SSL_DEBUG_MSG( 3, ( "Supported Signature Algorithm found: %d" ",%d", sig_alg[i], sig_alg[i + 1] ) ); } #endif n += 2 + sig_alg_len; } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ /* Ignore certificate_authorities, we only have one cert anyway */ dn_len = ( ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 1 + n] << 8 ) | ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n] ) ); n += dn_len; if( ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST ); } exit: MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate request" ) ); return( 0 ); } #endif /* MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */ static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl ) { int ret; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) ); if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello done message" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } if( ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) || ssl->in_msg[0] != MBEDTLS_SSL_HS_SERVER_HELLO_DONE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server hello done message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO_DONE ); } ssl->state++; #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) mbedtls_ssl_recv_flight_completed( ssl ); #endif MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse server hello done" ) ); return( 0 ); } static int ssl_write_client_key_exchange( mbedtls_ssl_context *ssl ) { int ret; size_t i, n; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client key exchange" ) ); #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA ) { /* * DHM key exchange -- send G^X mod P */ n = ssl->handshake->dhm_ctx.len; ssl->out_msg[4] = (unsigned char)( n >> 8 ); ssl->out_msg[5] = (unsigned char)( n ); i = 6; ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx, (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ), &ssl->out_msg[i], n, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_public", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X ); MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX ); 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( ret ); } 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 ) { /* * ECDH key exchange -- send client public value */ i = 4; ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx, &n, &ssl->out_msg[i], 1000, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_public", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_ECP( 3, "ECDH: Q", &ssl->handshake->ecdh_ctx.Q ); 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( ret ); } MBEDTLS_SSL_DEBUG_MPI( 3, "ECDH: z", &ssl->handshake->ecdh_ctx.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__SOME__PSK_ENABLED) if( mbedtls_ssl_ciphersuite_uses_psk( ciphersuite_info ) ) { /* * opaque psk_identity<0..2^16-1>; */ if( ssl->conf->psk == NULL || ssl->conf->psk_identity == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key for PSK" ) ); return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ); } i = 4; n = ssl->conf->psk_identity_len; if( i + 2 + n > MBEDTLS_SSL_MAX_CONTENT_LEN ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity too long or " "SSL buffer too short" ) ); return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); } ssl->out_msg[i++] = (unsigned char)( n >> 8 ); ssl->out_msg[i++] = (unsigned char)( n ); memcpy( ssl->out_msg + i, ssl->conf->psk_identity, ssl->conf->psk_identity_len ); i += ssl->conf->psk_identity_len; #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ) { n = 0; } else #endif #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ) { if( ( ret = ssl_write_encrypted_pms( ssl, i, &n, 2 ) ) != 0 ) return( ret ); } else #endif #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ) { /* * ClientDiffieHellmanPublic public (DHM send G^X mod P) */ n = ssl->handshake->dhm_ctx.len; if( i + 2 + n > MBEDTLS_SSL_MAX_CONTENT_LEN ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity or DHM size too long" " or SSL buffer too short" ) ); return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); } ssl->out_msg[i++] = (unsigned char)( n >> 8 ); ssl->out_msg[i++] = (unsigned char)( n ); ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx, (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ), &ssl->out_msg[i], n, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_public", 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 ) { /* * ClientECDiffieHellmanPublic public; */ ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx, &n, &ssl->out_msg[i], MBEDTLS_SSL_MAX_CONTENT_LEN - i, ssl->conf->f_rng, ssl->conf->p_rng ); if( ret != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_public", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_ECP( 3, "ECDH: Q", &ssl->handshake->ecdh_ctx.Q ); } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } 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__SOME__PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) { i = 4; if( ( ret = ssl_write_encrypted_pms( ssl, i, &n, 0 ) ) != 0 ) return( ret ); } else #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */ { ((void) ciphersuite_info); MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } ssl->out_msglen = i + n; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE; ssl->state++; if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client key exchange" ) ); return( 0 ); } #if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) && \ !defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) && \ !defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) && \ !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \ !defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \ !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl ) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; int ret; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate verify" ) ); if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret ); return( ret ); } if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) ); ssl->state++; return( 0 ); } MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } #else static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl ) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; size_t n = 0, offset = 0; unsigned char hash[48]; unsigned char *hash_start = hash; mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE; unsigned int hashlen; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate verify" ) ); if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret ); return( ret ); } if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) ); ssl->state++; return( 0 ); } if( ssl->client_auth == 0 || mbedtls_ssl_own_cert( ssl ) == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) ); ssl->state++; return( 0 ); } if( mbedtls_ssl_own_key( ssl ) == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key for certificate" ) ); return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Make an RSA signature of the handshake digests */ ssl->handshake->calc_verify( ssl, hash ); #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 ) { /* * digitally-signed struct { * opaque md5_hash[16]; * opaque sha_hash[20]; * }; * * md5_hash * MD5(handshake_messages); * * sha_hash * SHA(handshake_messages); */ hashlen = 36; md_alg = MBEDTLS_MD_NONE; /* * For ECDSA, default hash is SHA-1 only */ if( mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), 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 ) { /* * digitally-signed struct { * opaque handshake_messages[handshake_messages_length]; * }; * * Taking shortcut here. We assume that the server always allows the * PRF Hash function and has sent it in the allowed signature * algorithms list received in the Certificate Request message. * * Until we encounter a server that does not, we will take this * shortcut. * * Reason: Otherwise we should have running hashes for SHA512 and SHA224 * in order to satisfy 'weird' needs from the server side. */ if( ssl->transform_negotiate->ciphersuite_info->mac == MBEDTLS_MD_SHA384 ) { md_alg = MBEDTLS_MD_SHA384; ssl->out_msg[4] = MBEDTLS_SSL_HASH_SHA384; } else { md_alg = MBEDTLS_MD_SHA256; ssl->out_msg[4] = MBEDTLS_SSL_HASH_SHA256; } ssl->out_msg[5] = mbedtls_ssl_sig_from_pk( mbedtls_ssl_own_key( ssl ) ); /* Info from md_alg will be used instead */ hashlen = 0; offset = 2; } else #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ { MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); } if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ), md_alg, hash_start, hashlen, ssl->out_msg + 6 + offset, &n, ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret ); return( ret ); } ssl->out_msg[4 + offset] = (unsigned char)( n >> 8 ); ssl->out_msg[5 + offset] = (unsigned char)( n ); ssl->out_msglen = 6 + n + offset; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_VERIFY; ssl->state++; if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); return( ret ); } MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate verify" ) ); return( ret ); } #endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED && !MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED && !MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED && !MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED && !MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED && !MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl ) { int ret; uint32_t lifetime; size_t ticket_len; unsigned char *ticket; const unsigned char *msg; MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) ); if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); } if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) ); return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } /* * struct { * uint32 ticket_lifetime_hint; * opaque ticket<0..2^16-1>; * } NewSessionTicket; * * 0 . 3 ticket_lifetime_hint * 4 . 5 ticket_len (n) * 6 . 5+n ticket content */ if( ssl->in_msg[0] != MBEDTLS_SSL_HS_NEW_SESSION_TICKET || ssl->in_hslen < 6 + mbedtls_ssl_hs_hdr_len( ssl ) ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET ); } msg = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ); lifetime = ( ((uint32_t) msg[0]) << 24 ) | ( msg[1] << 16 ) | ( msg[2] << 8 ) | ( msg[3] ); ticket_len = ( msg[4] << 8 ) | ( msg[5] ); if( ticket_len + 6 + mbedtls_ssl_hs_hdr_len( ssl ) != ssl->in_hslen ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad new session ticket message" ) ); return( MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET ); } MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %d", ticket_len ) ); /* We're not waiting for a NewSessionTicket message any more */ ssl->handshake->new_session_ticket = 0; ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC; /* * Zero-length ticket means the server changed his mind and doesn't want * to send a ticket after all, so just forget it */ if( ticket_len == 0 ) return( 0 ); mbedtls_zeroize( ssl->session_negotiate->ticket, ssl->session_negotiate->ticket_len ); mbedtls_free( ssl->session_negotiate->ticket ); ssl->session_negotiate->ticket = NULL; ssl->session_negotiate->ticket_len = 0; if( ( ticket = mbedtls_calloc( 1, ticket_len ) ) == NULL ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "ticket alloc failed" ) ); return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); } memcpy( ticket, msg + 6, ticket_len ); ssl->session_negotiate->ticket = ticket; ssl->session_negotiate->ticket_len = ticket_len; ssl->session_negotiate->ticket_lifetime = lifetime; /* * RFC 5077 section 3.4: * "If the client receives a session ticket from the server, then it * discards any Session ID that was sent in the ServerHello." */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket in use, discarding session id" ) ); ssl->session_negotiate->id_len = 0; MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse new session ticket" ) ); return( 0 ); } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ /* * SSL handshake -- client side -- single step */ int mbedtls_ssl_handshake_client_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, ( "client 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_resend( ssl ) ) != 0 ) return( ret ); } #endif /* Change state now, so that it is right in mbedtls_ssl_read_record(), used * by DTLS for dropping out-of-sequence ChangeCipherSpec records */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) if( ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC && ssl->handshake->new_session_ticket != 0 ) { ssl->state = MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET; } #endif switch( ssl->state ) { case MBEDTLS_SSL_HELLO_REQUEST: ssl->state = MBEDTLS_SSL_CLIENT_HELLO; break; /* * ==> ClientHello */ case MBEDTLS_SSL_CLIENT_HELLO: ret = ssl_write_client_hello( ssl ); break; /* * <== ServerHello * Certificate * ( ServerKeyExchange ) * ( CertificateRequest ) * ServerHelloDone */ case MBEDTLS_SSL_SERVER_HELLO: ret = ssl_parse_server_hello( ssl ); break; case MBEDTLS_SSL_SERVER_CERTIFICATE: ret = mbedtls_ssl_parse_certificate( ssl ); break; case MBEDTLS_SSL_SERVER_KEY_EXCHANGE: ret = ssl_parse_server_key_exchange( ssl ); break; case MBEDTLS_SSL_CERTIFICATE_REQUEST: ret = ssl_parse_certificate_request( ssl ); break; case MBEDTLS_SSL_SERVER_HELLO_DONE: ret = ssl_parse_server_hello_done( ssl ); break; /* * ==> ( Certificate/Alert ) * ClientKeyExchange * ( CertificateVerify ) * ChangeCipherSpec * Finished */ case MBEDTLS_SSL_CLIENT_CERTIFICATE: ret = mbedtls_ssl_write_certificate( ssl ); break; case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE: ret = ssl_write_client_key_exchange( ssl ); break; case MBEDTLS_SSL_CERTIFICATE_VERIFY: ret = ssl_write_certificate_verify( ssl ); break; case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC: ret = mbedtls_ssl_write_change_cipher_spec( ssl ); break; case MBEDTLS_SSL_CLIENT_FINISHED: ret = mbedtls_ssl_write_finished( ssl ); break; /* * <== ( NewSessionTicket ) * ChangeCipherSpec * Finished */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) case MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET: ret = ssl_parse_new_session_ticket( ssl ); break; #endif case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC: ret = mbedtls_ssl_parse_change_cipher_spec( ssl ); break; case MBEDTLS_SSL_SERVER_FINISHED: ret = mbedtls_ssl_parse_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_CLI_C */