/* * SSLv3/TLSv1 server-side functions * * Copyright (C) 2006-2014, ARM Limited, All Rights Reserved * * This file is part of mbed TLS (https://tls.mbed.org) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #if !defined(POLARSSL_CONFIG_FILE) #include "mbedtls/config.h" #else #include POLARSSL_CONFIG_FILE #endif #if defined(POLARSSL_SSL_SRV_C) #include "mbedtls/debug.h" #include "mbedtls/ssl.h" #include #if defined(POLARSSL_ECP_C) #include "mbedtls/ecp.h" #endif #if defined(POLARSSL_PLATFORM_C) #include "mbedtls/platform.h" #else #include #define polarssl_malloc malloc #define polarssl_free free #endif #if defined(POLARSSL_HAVE_TIME) #include #endif #if defined(POLARSSL_SSL_SESSION_TICKETS) /* Implementation that should never be optimized out by the compiler */ static void polarssl_zeroize( void *v, size_t n ) { volatile unsigned char *p = v; while( n-- ) *p++ = 0; } /* * Serialize a session in the following format: * 0 . n-1 session structure, n = sizeof(ssl_session) * n . n+2 peer_cert length = m (0 if no certificate) * n+3 . n+2+m peer cert ASN.1 * * Assumes ticket is NULL (always true on server side). */ static int ssl_save_session( const ssl_session *session, unsigned char *buf, size_t buf_len, size_t *olen ) { unsigned char *p = buf; size_t left = buf_len; #if defined(POLARSSL_X509_CRT_PARSE_C) size_t cert_len; #endif /* POLARSSL_X509_CRT_PARSE_C */ if( left < sizeof( ssl_session ) ) return( -1 ); memcpy( p, session, sizeof( ssl_session ) ); p += sizeof( ssl_session ); left -= sizeof( ssl_session ); #if defined(POLARSSL_X509_CRT_PARSE_C) if( session->peer_cert == NULL ) cert_len = 0; else cert_len = session->peer_cert->raw.len; if( left < 3 + cert_len ) return( -1 ); *p++ = (unsigned char)( cert_len >> 16 & 0xFF ); *p++ = (unsigned char)( cert_len >> 8 & 0xFF ); *p++ = (unsigned char)( cert_len & 0xFF ); if( session->peer_cert != NULL ) memcpy( p, session->peer_cert->raw.p, cert_len ); p += cert_len; #endif /* POLARSSL_X509_CRT_PARSE_C */ *olen = p - buf; return( 0 ); } /* * Unserialise session, see ssl_save_session() */ static int ssl_load_session( ssl_session *session, const unsigned char *buf, size_t len ) { const unsigned char *p = buf; const unsigned char * const end = buf + len; #if defined(POLARSSL_X509_CRT_PARSE_C) size_t cert_len; #endif /* POLARSSL_X509_CRT_PARSE_C */ if( p + sizeof( ssl_session ) > end ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); memcpy( session, p, sizeof( ssl_session ) ); p += sizeof( ssl_session ); #if defined(POLARSSL_X509_CRT_PARSE_C) if( p + 3 > end ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); cert_len = ( p[0] << 16 ) | ( p[1] << 8 ) | p[2]; p += 3; if( cert_len == 0 ) { session->peer_cert = NULL; } else { int ret; if( p + cert_len > end ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); session->peer_cert = polarssl_malloc( sizeof( x509_crt ) ); if( session->peer_cert == NULL ) return( POLARSSL_ERR_SSL_MALLOC_FAILED ); x509_crt_init( session->peer_cert ); if( ( ret = x509_crt_parse_der( session->peer_cert, p, cert_len ) ) != 0 ) { x509_crt_free( session->peer_cert ); polarssl_free( session->peer_cert ); session->peer_cert = NULL; return( ret ); } p += cert_len; } #endif /* POLARSSL_X509_CRT_PARSE_C */ if( p != end ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); return( 0 ); } /* * Create session ticket, secured as recommended in RFC 5077 section 4: * * struct { * opaque key_name[16]; * opaque iv[16]; * opaque encrypted_state<0..2^16-1>; * opaque mac[32]; * } ticket; * * (the internal state structure differs, however). */ static int ssl_write_ticket( ssl_context *ssl, size_t *tlen ) { int ret; unsigned char * const start = ssl->out_msg + 10; unsigned char *p = start; unsigned char *state; unsigned char iv[16]; size_t clear_len, enc_len, pad_len, i; *tlen = 0; if( ssl->ticket_keys == NULL ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); /* Write key name */ memcpy( p, ssl->ticket_keys->key_name, 16 ); p += 16; /* Generate and write IV (with a copy for aes_crypt) */ if( ( ret = ssl->f_rng( ssl->p_rng, p, 16 ) ) != 0 ) return( ret ); memcpy( iv, p, 16 ); p += 16; /* * Dump session state * * After the session state itself, we still need room for 16 bytes of * padding and 32 bytes of MAC, so there's only so much room left */ state = p + 2; if( ssl_save_session( ssl->session_negotiate, state, SSL_MAX_CONTENT_LEN - ( state - ssl->out_msg ) - 48, &clear_len ) != 0 ) { return( POLARSSL_ERR_SSL_CERTIFICATE_TOO_LARGE ); } SSL_DEBUG_BUF( 3, "session ticket cleartext", state, clear_len ); /* Apply PKCS padding */ pad_len = 16 - clear_len % 16; enc_len = clear_len + pad_len; for( i = clear_len; i < enc_len; i++ ) state[i] = (unsigned char) pad_len; /* Encrypt */ if( ( ret = aes_crypt_cbc( &ssl->ticket_keys->enc, AES_ENCRYPT, enc_len, iv, state, state ) ) != 0 ) { return( ret ); } /* Write length */ *p++ = (unsigned char)( ( enc_len >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( enc_len ) & 0xFF ); p = state + enc_len; /* Compute and write MAC( key_name + iv + enc_state_len + enc_state ) */ if( ( ret = md_hmac( md_info_from_type( POLARSSL_MD_SHA256 ), ssl->ticket_keys->mac_key, 16, start, p - start, p ) ) != 0 ) { return( ret ); } p += 32; *tlen = p - start; SSL_DEBUG_BUF( 3, "session ticket structure", start, *tlen ); return( 0 ); } /* * Load session ticket (see ssl_write_ticket for structure) */ static int ssl_parse_ticket( ssl_context *ssl, unsigned char *buf, size_t len ) { int ret; ssl_session session; unsigned char *key_name = buf; unsigned char *iv = buf + 16; unsigned char *enc_len_p = iv + 16; unsigned char *ticket = enc_len_p + 2; unsigned char *mac; unsigned char computed_mac[32]; size_t enc_len, clear_len, i; unsigned char pad_len, diff; SSL_DEBUG_BUF( 3, "session ticket structure", buf, len ); if( len < 34 || ssl->ticket_keys == NULL ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); enc_len = ( enc_len_p[0] << 8 ) | enc_len_p[1]; mac = ticket + enc_len; if( len != enc_len + 66 ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); /* Check name, in constant time though it's not a big secret */ diff = 0; for( i = 0; i < 16; i++ ) diff |= key_name[i] ^ ssl->ticket_keys->key_name[i]; /* don't return yet, check the MAC anyway */ /* Check mac, with constant-time buffer comparison */ if( ( ret = md_hmac( md_info_from_type( POLARSSL_MD_SHA256 ), ssl->ticket_keys->mac_key, 16, buf, len - 32, computed_mac ) ) != 0 ) { return( ret ); } for( i = 0; i < 32; i++ ) diff |= mac[i] ^ computed_mac[i]; /* Now return if ticket is not authentic, since we want to avoid * decrypting arbitrary attacker-chosen data */ if( diff != 0 ) return( POLARSSL_ERR_SSL_INVALID_MAC ); /* Decrypt */ if( ( ret = aes_crypt_cbc( &ssl->ticket_keys->dec, AES_DECRYPT, enc_len, iv, ticket, ticket ) ) != 0 ) { return( ret ); } /* Check PKCS padding */ pad_len = ticket[enc_len - 1]; ret = 0; for( i = 2; i < pad_len; i++ ) if( ticket[enc_len - i] != pad_len ) ret = POLARSSL_ERR_SSL_BAD_INPUT_DATA; if( ret != 0 ) return( ret ); clear_len = enc_len - pad_len; SSL_DEBUG_BUF( 3, "session ticket cleartext", ticket, clear_len ); /* Actually load session */ if( ( ret = ssl_load_session( &session, ticket, clear_len ) ) != 0 ) { SSL_DEBUG_MSG( 1, ( "failed to parse ticket content" ) ); ssl_session_free( &session ); return( ret ); } #if defined(POLARSSL_HAVE_TIME) /* Check if still valid */ if( (int) ( time( NULL) - session.start ) > ssl->ticket_lifetime ) { SSL_DEBUG_MSG( 1, ( "session ticket expired" ) ); ssl_session_free( &session ); return( POLARSSL_ERR_SSL_SESSION_TICKET_EXPIRED ); } #endif /* * Keep the session ID sent by the client, since we MUST send it back to * inform him we're accepting the ticket (RFC 5077 section 3.4) */ session.length = ssl->session_negotiate->length; memcpy( &session.id, ssl->session_negotiate->id, session.length ); ssl_session_free( ssl->session_negotiate ); memcpy( ssl->session_negotiate, &session, sizeof( ssl_session ) ); /* Zeroize instead of free as we copied the content */ polarssl_zeroize( &session, sizeof( ssl_session ) ); return( 0 ); } #endif /* POLARSSL_SSL_SESSION_TICKETS */ #if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY) int ssl_set_client_transport_id( ssl_context *ssl, const unsigned char *info, size_t ilen ) { if( ssl->endpoint != SSL_IS_SERVER ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); polarssl_free( ssl->cli_id ); if( ( ssl->cli_id = polarssl_malloc( ilen ) ) == NULL ) return( POLARSSL_ERR_SSL_MALLOC_FAILED ); memcpy( ssl->cli_id, info, ilen ); ssl->cli_id_len = ilen; return( 0 ); } void ssl_set_dtls_cookies( ssl_context *ssl, ssl_cookie_write_t *f_cookie_write, ssl_cookie_check_t *f_cookie_check, void *p_cookie ) { ssl->f_cookie_write = f_cookie_write; ssl->f_cookie_check = f_cookie_check; ssl->p_cookie = p_cookie; } #endif /* POLARSSL_SSL_DTLS_HELLO_VERIFY */ #if defined(POLARSSL_SSL_SERVER_NAME_INDICATION) /* * Wrapper around f_sni, allowing use of ssl_set_own_cert() but * making it act on ssl->handshake->sni_key_cert instead. */ static int ssl_sni_wrapper( ssl_context *ssl, const unsigned char* name, size_t len ) { int ret; ssl_key_cert *key_cert_ori = ssl->key_cert; ssl->key_cert = NULL; ret = ssl->f_sni( ssl->p_sni, ssl, name, len ); ssl->handshake->sni_key_cert = ssl->key_cert; ssl->key_cert = key_cert_ori; return( ret ); } static int ssl_parse_servername_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret; size_t servername_list_size, hostname_len; const unsigned char *p; SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) ); servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( servername_list_size + 2 != len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } p = buf + 2; while( servername_list_size > 0 ) { hostname_len = ( ( p[1] << 8 ) | p[2] ); if( hostname_len + 3 > servername_list_size ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( p[0] == TLS_EXT_SERVERNAME_HOSTNAME ) { ret = ssl_sni_wrapper( ssl, p + 3, hostname_len ); if( ret != 0 ) { SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_UNRECOGNIZED_NAME ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } servername_list_size -= hostname_len + 3; p += hostname_len + 3; } if( servername_list_size != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } return( 0 ); } #endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */ static int ssl_parse_renegotiation_info( ssl_context *ssl, const unsigned char *buf, size_t len ) { int ret; #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status != 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 || safer_memcmp( buf + 1, ssl->peer_verify_data, ssl->verify_data_len ) != 0 ) { SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } else #endif /* POLARSSL_SSL_RENEGOTIATION */ { if( len != 1 || buf[0] != 0x0 ) { SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; } return( 0 ); } #if defined(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) static int ssl_parse_signature_algorithms_ext( 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; const int *md_cur; sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( sig_alg_list_size + 2 != len || sig_alg_list_size % 2 != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * For now, ignore the SignatureAlgorithm part and rely on offered * ciphersuites only for that part. To be fixed later. * * So, just look at the HashAlgorithm part. */ for( md_cur = md_list(); *md_cur != POLARSSL_MD_NONE; md_cur++ ) { for( p = buf + 2; p < end; p += 2 ) { if( *md_cur == (int) ssl_md_alg_from_hash( p[0] ) ) { ssl->handshake->sig_alg = p[0]; goto have_sig_alg; } } } /* Some key echanges do not need signatures at all */ SSL_DEBUG_MSG( 3, ( "no signature_algorithm in common" ) ); return( 0 ); have_sig_alg: SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d", ssl->handshake->sig_alg ) ); return( 0 ); } #endif /* POLARSSL_SSL_PROTO_TLS1_2 && POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */ #if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C) static int ssl_parse_supported_elliptic_curves( ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t list_size, our_size; const unsigned char *p; const ecp_curve_info *curve_info, **curves; list_size = ( ( buf[0] << 8 ) | ( buf[1] ) ); if( list_size + 2 != len || list_size % 2 != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* Should never happen unless client duplicates the extension */ if( ssl->handshake->curves != NULL ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_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 > POLARSSL_ECP_DP_MAX ) our_size = POLARSSL_ECP_DP_MAX; if( ( curves = polarssl_malloc( our_size * sizeof( *curves ) ) ) == NULL ) return( POLARSSL_ERR_SSL_MALLOC_FAILED ); /* explicit void pointer cast for buggy MS compiler */ memset( (void *) curves, 0, our_size * sizeof( *curves ) ); ssl->handshake->curves = curves; p = buf + 2; while( list_size > 0 && our_size > 1 ) { curve_info = 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( ssl_context *ssl, const unsigned char *buf, size_t len ) { size_t list_size; const unsigned char *p; list_size = buf[0]; if( list_size + 1 != len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } p = buf + 2; while( list_size > 0 ) { if( p[0] == POLARSSL_ECP_PF_UNCOMPRESSED || p[0] == POLARSSL_ECP_PF_COMPRESSED ) { ssl->handshake->ecdh_ctx.point_format = p[0]; SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) ); return( 0 ); } list_size--; p++; } return( 0 ); } #endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */ #if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH) static int ssl_parse_max_fragment_length_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 1 || buf[0] >= SSL_MAX_FRAG_LEN_INVALID ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->session_negotiate->mfl_code = buf[0]; return( 0 ); } #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */ #if defined(POLARSSL_SSL_TRUNCATED_HMAC) static int ssl_parse_truncated_hmac_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->trunc_hmac == SSL_TRUNC_HMAC_ENABLED ) ssl->session_negotiate->trunc_hmac = SSL_TRUNC_HMAC_ENABLED; return( 0 ); } #endif /* POLARSSL_SSL_TRUNCATED_HMAC */ #if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC) static int ssl_parse_encrypt_then_mac_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->encrypt_then_mac == SSL_ETM_ENABLED && ssl->minor_ver != SSL_MINOR_VERSION_0 ) { ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED; } return( 0 ); } #endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */ #if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET) static int ssl_parse_extended_ms_ext( ssl_context *ssl, const unsigned char *buf, size_t len ) { if( len != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ((void) buf); if( ssl->extended_ms == SSL_EXTENDED_MS_ENABLED && ssl->minor_ver != SSL_MINOR_VERSION_0 ) { ssl->handshake->extended_ms = SSL_EXTENDED_MS_ENABLED; } return( 0 ); } #endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */ #if defined(POLARSSL_SSL_SESSION_TICKETS) static int ssl_parse_session_ticket_ext( ssl_context *ssl, unsigned char *buf, size_t len ) { int ret; if( ssl->session_tickets == SSL_SESSION_TICKETS_DISABLED ) return( 0 ); /* Remember the client asked us to send a new ticket */ ssl->handshake->new_session_ticket = 1; SSL_DEBUG_MSG( 3, ( "ticket length: %d", len ) ); if( len == 0 ) return( 0 ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status != SSL_INITIAL_HANDSHAKE ) { SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) ); return( 0 ); } #endif /* POLARSSL_SSL_RENEGOTIATION */ /* * Failures are ok: just ignore the ticket and proceed. */ if( ( ret = ssl_parse_ticket( ssl, buf, len ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_parse_ticket", ret ); return( 0 ); } 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 /* POLARSSL_SSL_SESSION_TICKETS */ #if defined(POLARSSL_SSL_ALPN) static int ssl_parse_alpn_ext( 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->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 ) return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); list_len = ( buf[0] << 8 ) | buf[1]; if( list_len != len - 2 ) return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); /* * Use our order of preference */ start = buf + 2; end = buf + len; for( ours = ssl->alpn_list; *ours != NULL; ours++ ) { ours_len = strlen( *ours ); for( theirs = start; theirs != end; theirs += cur_len ) { /* If the list is well formed, we should get equality first */ if( theirs > end ) return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); cur_len = *theirs++; /* Empty strings MUST NOT be included */ if( cur_len == 0 ) return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); 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 */ ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* POLARSSL_SSL_ALPN */ /* * Auxiliary functions for ServerHello parsing and related actions */ #if defined(POLARSSL_X509_CRT_PARSE_C) /* * Return 0 if the given key uses one of the acceptable curves, -1 otherwise */ #if defined(POLARSSL_ECDSA_C) static int ssl_check_key_curve( pk_context *pk, const ecp_curve_info **curves ) { const ecp_curve_info **crv = curves; ecp_group_id grp_id = pk_ec( *pk )->grp.id; while( *crv != NULL ) { if( (*crv)->grp_id == grp_id ) return( 0 ); crv++; } return( -1 ); } #endif /* POLARSSL_ECDSA_C */ /* * Try picking a certificate for this ciphersuite, * return 0 on success and -1 on failure. */ static int ssl_pick_cert( ssl_context *ssl, const ssl_ciphersuite_t * ciphersuite_info ) { ssl_key_cert *cur, *list, *fallback = NULL; pk_type_t pk_alg = ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); #if defined(POLARSSL_SSL_SERVER_NAME_INDICATION) if( ssl->handshake->sni_key_cert != NULL ) list = ssl->handshake->sni_key_cert; else #endif list = ssl->handshake->key_cert; if( pk_alg == POLARSSL_PK_NONE ) return( 0 ); SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) ); for( cur = list; cur != NULL; cur = cur->next ) { SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate", cur->cert ); if( ! pk_can_do( cur->key, pk_alg ) ) { 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( ssl_check_cert_usage( cur->cert, ciphersuite_info, SSL_IS_SERVER ) != 0 ) { SSL_DEBUG_MSG( 3, ( "certificate mismatch: " "(extended) key usage extension" ) ); continue; } #if defined(POLARSSL_ECDSA_C) if( pk_alg == POLARSSL_PK_ECDSA && ssl_check_key_curve( cur->key, ssl->handshake->curves ) != 0 ) { 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 < SSL_MINOR_VERSION_3 && cur->cert->sig_md != POLARSSL_MD_SHA1 ) { if( fallback == NULL ) fallback = cur; { 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 the is a match */ if( cur != NULL ) { ssl->handshake->key_cert = cur; SSL_DEBUG_CRT( 3, "selected certificate chain, certificate", ssl->handshake->key_cert->cert ); return( 0 ); } return( -1 ); } #endif /* POLARSSL_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( ssl_context *ssl, int suite_id, const ssl_ciphersuite_t **ciphersuite_info ) { const ssl_ciphersuite_t *suite_info; suite_info = ssl_ciphersuite_from_id( suite_id ); if( suite_info == NULL ) { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %s", suite_info->name ) ); if( suite_info->min_minor_ver > ssl->minor_ver || suite_info->max_minor_ver < ssl->minor_ver ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) ); return( 0 ); } #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM && ( suite_info->flags & POLARSSL_CIPHERSUITE_NODTLS ) ) return( 0 ); #endif if( ssl->arc4_disabled == SSL_ARC4_DISABLED && suite_info->cipher == POLARSSL_CIPHER_ARC4_128 ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) ); return( 0 ); } #if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C) if( ssl_ciphersuite_uses_ec( suite_info ) && ( ssl->handshake->curves == NULL || ssl->handshake->curves[0] == NULL ) ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: " "no common elliptic curve" ) ); return( 0 ); } #endif #if defined(POLARSSL_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( ssl_ciphersuite_uses_psk( suite_info ) && ssl->f_psk == NULL && ( ssl->psk == NULL || ssl->psk_identity == NULL || ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) ); return( 0 ); } #endif #if defined(POLARSSL_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 ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: " "no suitable certificate" ) ); return( 0 ); } #endif *ciphersuite_info = suite_info; return( 0 ); } #if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) static int ssl_parse_client_hello_v2( 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 ssl_ciphersuite_t *ciphersuite_info; SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status != SSL_INITIAL_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* POLARSSL_SSL_RENEGOTIATION */ buf = ssl->in_hdr; SSL_DEBUG_BUF( 4, "record header", buf, 5 ); SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d", buf[2] ) ); SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d", ( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) ); 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] != SSL_HS_CLIENT_HELLO || buf[3] != SSL_MAJOR_VERSION_3 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF; if( n < 17 || n > 512 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->major_ver = SSL_MAJOR_VERSION_3; ssl->minor_ver = ( buf[4] <= ssl->max_minor_ver ) ? buf[4] : ssl->max_minor_ver; if( ssl->minor_ver < ssl->min_minor_ver ) { SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->min_major_ver, ssl->min_minor_ver ) ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_PROTOCOL_VERSION ); return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION ); } ssl->handshake->max_major_ver = buf[3]; ssl->handshake->max_minor_ver = buf[4]; if( ( ret = ssl_fetch_input( ssl, 2 + n ) ) != 0 ) { SSL_DEBUG_RET( 1, "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 */ 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]; SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d", ciph_len, sess_len, chal_len ) ); /* * Make sure each parameter length is valid */ if( ciph_len < 3 || ( ciph_len % 3 ) != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( sess_len > 32 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( chal_len < 8 || chal_len > 32 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( n != 6 + ciph_len + sess_len + chal_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", buf + 6, ciph_len ); SSL_DEBUG_BUF( 3, "client hello, session id", buf + 6 + ciph_len, sess_len ); SSL_DEBUG_BUF( 3, "client hello, challenge", buf + 6 + ciph_len + sess_len, chal_len ); p = buf + 6 + ciph_len; ssl->session_negotiate->length = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->length ); 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] == SSL_EMPTY_RENEGOTIATION_INFO ) { SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS ) { SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV " "during renegotiation" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif /* POLARSSL_SSL_RENEGOTIATION */ ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; break; } } #if defined(POLARSSL_SSL_FALLBACK_SCSV) for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 ) { if( p[0] == 0 && p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) && p[2] == (unsigned char)( ( SSL_FALLBACK_SCSV_VALUE ) & 0xff ) ) { SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) ); if( ssl->minor_ver < ssl->max_minor_ver ) { SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_INAPROPRIATE_FALLBACK ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } break; } } #endif /* POLARSSL_SSL_FALLBACK_SCSV */ got_common_suite = 0; ciphersuites = ssl->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(POLARSSL_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 ) { SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, " "but none of them usable" ) ); return( POLARSSL_ERR_SSL_NO_USABLE_CIPHERSUITE ); } else { SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) ); return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN ); } have_ciphersuite_v2: SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) ); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->transform_negotiate->ciphersuite_info = ciphersuite_info; ssl_optimize_checksum( ssl, ssl->transform_negotiate->ciphersuite_info ); /* * SSLv2 Client Hello relevant renegotiation security checks */ if( ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->in_left = 0; ssl->state++; SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) ); return( 0 ); } #endif /* POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */ static int ssl_parse_client_hello( ssl_context *ssl ) { int ret, got_common_suite; unsigned int i, j; unsigned int ciph_offset, comp_offset, ext_offset; unsigned int msg_len, ciph_len, sess_len, comp_len, ext_len; #if defined(POLARSSL_SSL_PROTO_DTLS) unsigned int cookie_offset, cookie_len; #endif unsigned char *buf, *p, *ext; #if defined(POLARSSL_SSL_RENEGOTIATION) int renegotiation_info_seen = 0; #endif int handshake_failure = 0; const int *ciphersuites; const ssl_ciphersuite_t *ciphersuite_info; int major, minor; SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) ); #if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY) read_record_header: #endif /* * If renegotiating, then the input was read with 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(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status == SSL_INITIAL_HANDSHAKE ) #endif { if( ( ret = ssl_fetch_input( ssl, 5 ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_fetch_input", ret ); return( ret ); } } buf = ssl->in_hdr; #if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_STREAM ) #endif if( ( buf[0] & 0x80 ) != 0 ) return ssl_parse_client_hello_v2( ssl ); #endif SSL_DEBUG_BUF( 4, "record header", buf, ssl_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 */ SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d", buf[0] ) ); if( buf[0] != SSL_MSG_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d", ( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]", buf[1], buf[2] ) ); ssl_read_version( &major, &minor, ssl->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 < SSL_MAJOR_VERSION_3 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_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(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM #if defined(POLARSSL_SSL_RENEGOTIATION) && ssl->renego_status == SSL_INITIAL_HANDSHAKE #endif ) { /* Epoch should be 0 for initial handshakes */ if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } memcpy( ssl->out_ctr + 2, ssl->in_ctr + 2, 6 ); #if defined(POLARSSL_SSL_DTLS_ANTI_REPLAY) if( ssl_dtls_replay_check( ssl ) != 0 ) { 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 */ ssl_dtls_replay_update( ssl ); #endif } #endif /* POLARSSL_SSL_PROTO_DTLS */ msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1]; #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status != SSL_INITIAL_HANDSHAKE ) { /* Set by ssl_read_record() */ msg_len = ssl->in_hslen; } else #endif { if( msg_len > SSL_MAX_CONTENT_LEN ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } if( ( ret = ssl_fetch_input( ssl, ssl_hdr_len( ssl ) + msg_len ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_fetch_input", ret ); return( ret ); } /* Done reading this record, get ready for the next one */ #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) ssl->next_record_offset = msg_len + ssl_hdr_len( ssl ); else #endif ssl->in_left = 0; } buf = ssl->in_msg; 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 < ssl_hs_hdr_len( ssl ) ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) ); if( buf[0] != SSL_HS_CLIENT_HELLO ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } 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 != ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) { /* * Copy the client's handshake message_seq on initial handshakes, * check sequence number on renego. */ #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status == 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 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: " "%d (expected %d)", cli_msg_seq, ssl->handshake->in_msg_seq ) ); return( POLARSSL_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 ) { SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) ); return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE ); } } #endif /* POLARSSL_SSL_PROTO_DTLS */ buf += ssl_hs_hdr_len( ssl ); msg_len -= 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 ommitted) 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 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check and save the protocol version */ SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 ); ssl_read_version( &ssl->major_ver, &ssl->minor_ver, ssl->transport, buf ); ssl->handshake->max_major_ver = ssl->major_ver; ssl->handshake->max_minor_ver = ssl->minor_ver; if( ssl->major_ver < ssl->min_major_ver || ssl->minor_ver < ssl->min_minor_ver ) { SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->min_major_ver, ssl->min_minor_ver ) ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_PROTOCOL_VERSION ); return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION ); } if( ssl->major_ver > ssl->max_major_ver ) { ssl->major_ver = ssl->max_major_ver; ssl->minor_ver = ssl->max_minor_ver; } else if( ssl->minor_ver > ssl->max_minor_ver ) ssl->minor_ver = ssl->max_minor_ver; /* * Save client random (inc. Unix time) */ 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 */ { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len ); ssl->session_negotiate->length = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, buf + 35, ssl->session_negotiate->length ); /* * Check the cookie length and content */ #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) { cookie_offset = 35 + sess_len; cookie_len = buf[cookie_offset]; if( cookie_offset + 1 + cookie_len + 2 > msg_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_BUF( 3, "client hello, cookie", buf + cookie_offset + 1, cookie_len ); #if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY) if( ssl->f_cookie_check != NULL #if defined(POLARSSL_SSL_RENEGOTIATION) && ssl->renego_status == SSL_INITIAL_HANDSHAKE #endif ) { if( ssl->f_cookie_check( ssl->p_cookie, buf + cookie_offset + 1, cookie_len, ssl->cli_id, ssl->cli_id_len ) != 0 ) { SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) ); ssl->handshake->verify_cookie_len = 1; } else { SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) ); ssl->handshake->verify_cookie_len = 0; } } else #endif /* POLARSSL_SSL_DTLS_HELLO_VERIFY */ { /* We know we didn't send a cookie, so it should be empty */ if( cookie_len != 0 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) ); } /* * Check the ciphersuitelist length (will be parsed later) */ ciph_offset = cookie_offset + 1 + cookie_len; } else #endif /* POLARSSL_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 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } 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 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } SSL_DEBUG_BUF( 3, "client hello, compression", buf + comp_offset + 1, comp_len ); ssl->session_negotiate->compression = SSL_COMPRESS_NULL; #if defined(POLARSSL_ZLIB_SUPPORT) for( i = 0; i < comp_len; ++i ) { if( buf[comp_offset + 1 + i] == SSL_COMPRESS_DEFLATE ) { ssl->session_negotiate->compression = SSL_COMPRESS_DEFLATE; break; } } #endif /* See comments in ssl_write_client_hello() */ #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) ssl->session_negotiate->compression = SSL_COMPRESS_NULL; #endif /* * Check the extension length */ ext_offset = comp_offset + 1 + comp_len; if( msg_len > ext_offset ) { if( msg_len < ext_offset + 2 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ext_len = ( buf[ext_offset + 0] << 8 ) | ( buf[ext_offset + 1] ); if( ( ext_len > 0 && ext_len < 4 ) || msg_len != ext_offset + 2 + ext_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); SSL_DEBUG_BUF( 3, "client hello extensions", buf + ext_offset + 2, ext_len ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } else ext_len = 0; ext = buf + ext_offset + 2; while( ext_len != 0 ) { unsigned int ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) ); unsigned int ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) ); if( ext_size + 4 > ext_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } switch( ext_id ) { #if defined(POLARSSL_SSL_SERVER_NAME_INDICATION) case TLS_EXT_SERVERNAME: SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) ); if( ssl->f_sni == NULL ) break; ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */ case TLS_EXT_RENEGOTIATION_INFO: SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) ); #if defined(POLARSSL_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(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) case TLS_EXT_SIG_ALG: SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS ) break; #endif ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* POLARSSL_SSL_PROTO_TLS1_2 && POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */ #if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C) case TLS_EXT_SUPPORTED_ELLIPTIC_CURVES: 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 TLS_EXT_SUPPORTED_POINT_FORMATS: SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) ); ssl->handshake->cli_exts |= TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT; ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */ #if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH) case TLS_EXT_MAX_FRAGMENT_LENGTH: 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 /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */ #if defined(POLARSSL_SSL_TRUNCATED_HMAC) case TLS_EXT_TRUNCATED_HMAC: 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 /* POLARSSL_SSL_TRUNCATED_HMAC */ #if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC) case TLS_EXT_ENCRYPT_THEN_MAC: 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 /* POLARSSL_SSL_ENCRYPT_THEN_MAC */ #if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET) case TLS_EXT_EXTENDED_MASTER_SECRET: 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 /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */ #if defined(POLARSSL_SSL_SESSION_TICKETS) case TLS_EXT_SESSION_TICKET: 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 /* POLARSSL_SSL_SESSION_TICKETS */ #if defined(POLARSSL_SSL_ALPN) case TLS_EXT_ALPN: SSL_DEBUG_MSG( 3, ( "found alpn extension" ) ); ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); break; #endif /* POLARSSL_SSL_SESSION_TICKETS */ default: 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 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } #if defined(POLARSSL_SSL_FALLBACK_SCSV) for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 ) { if( p[0] == (unsigned char)( ( SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) && p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV_VALUE ) & 0xff ) ) { SSL_DEBUG_MSG( 0, ( "received FALLBACK_SCSV" ) ); if( ssl->minor_ver < ssl->max_minor_ver ) { SSL_DEBUG_MSG( 0, ( "inapropriate fallback" ) ); ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_INAPROPRIATE_FALLBACK ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } break; } } #endif /* POLARSSL_SSL_FALLBACK_SCSV */ /* * 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] == SSL_EMPTY_RENEGOTIATION_INFO ) { SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS ) { SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV during renegotiation" ) ); if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #endif ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; break; } } /* * Renegotiation security checks */ if( ssl->secure_renegotiation != SSL_SECURE_RENEGOTIATION && ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) ); handshake_failure = 1; } #if defined(POLARSSL_SSL_RENEGOTIATION) else if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == SSL_SECURE_RENEGOTIATION && renegotiation_info_seen == 0 ) { SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) ); handshake_failure = 1; } else if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && ssl->allow_legacy_renegotiation == SSL_LEGACY_NO_RENEGOTIATION ) { SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) ); handshake_failure = 1; } else if( ssl->renego_status == SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION && renegotiation_info_seen == 1 ) { SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) ); handshake_failure = 1; } #endif /* POLARSSL_SSL_RENEGOTIATION */ if( handshake_failure == 1 ) { if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 ) return( ret ); return( POLARSSL_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->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(POLARSSL_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] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) || p[1] != ( ( 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; } } if( got_common_suite ) { SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, " "but none of them usable" ) ); ssl_send_fatal_handshake_failure( ssl ); return( POLARSSL_ERR_SSL_NO_USABLE_CIPHERSUITE ); } else { SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) ); ssl_send_fatal_handshake_failure( ssl ); return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN ); } have_ciphersuite: SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) ); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->transform_negotiate->ciphersuite_info = ciphersuite_info; ssl_optimize_checksum( ssl, ssl->transform_negotiate->ciphersuite_info ); ssl->state++; #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) ssl_recv_flight_completed( ssl ); #endif SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) ); return( 0 ); } #if defined(POLARSSL_SSL_TRUNCATED_HMAC) static void ssl_write_truncated_hmac_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->session_negotiate->trunc_hmac == SSL_TRUNC_HMAC_DISABLED ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC ) & 0xFF ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* POLARSSL_SSL_TRUNCATED_HMAC */ #if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC) static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; const ssl_ciphersuite_t *suite = NULL; const cipher_info_t *cipher = NULL; if( ssl->session_negotiate->encrypt_then_mac == SSL_EXTENDED_MS_DISABLED || ssl->minor_ver == 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 = ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) == NULL || ( cipher = cipher_info_from_type( suite->cipher ) ) == NULL || cipher->mode != POLARSSL_MODE_CBC ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */ #if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET) static void ssl_write_extended_ms_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->handshake->extended_ms == SSL_EXTENDED_MS_DISABLED || ssl->minor_ver == SSL_MINOR_VERSION_0 ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret " "extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */ #if defined(POLARSSL_SSL_SESSION_TICKETS) static void ssl_write_session_ticket_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->handshake->new_session_ticket == 0 ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET ) & 0xFF ); *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* POLARSSL_SSL_SESSION_TICKETS */ static void ssl_write_renegotiation_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->secure_renegotiation != SSL_SECURE_RENEGOTIATION ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO ) & 0xFF ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renego_status != 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; *olen = 5 + ssl->verify_data_len * 2; } else #endif /* POLARSSL_SSL_RENEGOTIATION */ { *p++ = 0x00; *p++ = 0x01; *p++ = 0x00; *olen = 5; } } #if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH) static void ssl_write_max_fragment_length_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; if( ssl->session_negotiate->mfl_code == SSL_MAX_FRAG_LEN_NONE ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF ); *p++ = 0x00; *p++ = 1; *p++ = ssl->session_negotiate->mfl_code; *olen = 5; } #endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */ #if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C) static void ssl_write_supported_point_formats_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { unsigned char *p = buf; ((void) ssl); if( ( ssl->handshake->cli_exts & TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 ) { *olen = 0; return; } SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) ); *p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF ); *p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF ); *p++ = 0x00; *p++ = 2; *p++ = 1; *p++ = POLARSSL_ECP_PF_UNCOMPRESSED; *olen = 6; } #endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */ #if defined(POLARSSL_SSL_ALPN ) static void ssl_write_alpn_ext( ssl_context *ssl, unsigned char *buf, size_t *olen ) { if( ssl->alpn_chosen == NULL ) { *olen = 0; return; } 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] = (unsigned char)( ( TLS_EXT_ALPN >> 8 ) & 0xFF ); buf[1] = (unsigned char)( ( TLS_EXT_ALPN ) & 0xFF ); *olen = 7 + strlen( ssl->alpn_chosen ); buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF ); buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF ); buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF ); buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF ); buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF ); memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 ); } #endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */ #if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY) static int ssl_write_hello_verify_request( ssl_context *ssl ) { int ret; unsigned char *p = ssl->out_msg + 4; unsigned char *cookie_len_byte; 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. */ ssl_write_version( ssl->major_ver, ssl->minor_ver, ssl->transport, p ); SSL_DEBUG_BUF( 3, "server version", p, 2 ); p += 2; /* If we get here, f_cookie_check is not null */ if( ssl->f_cookie_write == NULL ) { SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } /* Skip length byte until we know the length */ cookie_len_byte = p++; if( ( ret = ssl->f_cookie_write( ssl->p_cookie, &p, ssl->out_buf + SSL_BUFFER_LEN, ssl->cli_id, ssl->cli_id_len ) ) != 0 ) { SSL_DEBUG_RET( 1, "f_cookie_write", ret ); return( ret ); } *cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) ); SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte ); ssl->out_msglen = p - ssl->out_msg; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_HELLO_VERIFY_REQUEST; ssl->state = SSL_SERVER_HELLO_VERIFY_REQUEST_SENT; if( ( ret = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) ); return( 0 ); } #endif /* POLARSSL_SSL_DTLS_HELLO_VERIFY */ static int ssl_write_server_hello( ssl_context *ssl ) { #if defined(POLARSSL_HAVE_TIME) time_t t; #endif int ret; size_t olen, ext_len = 0, n; unsigned char *buf, *p; SSL_DEBUG_MSG( 2, ( "=> write server hello" ) ); #if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY) if( ssl->transport == SSL_TRANSPORT_DATAGRAM && ssl->handshake->verify_cookie_len != 0 ) { SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) ); SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); return( ssl_write_hello_verify_request( ssl ) ); } #endif /* POLARSSL_SSL_DTLS_HELLO_VERIFY */ if( ssl->f_rng == NULL ) { SSL_DEBUG_MSG( 1, ( "no RNG provided") ); return( POLARSSL_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; ssl_write_version( ssl->major_ver, ssl->minor_ver, ssl->transport, p ); p += 2; SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]", buf[4], buf[5] ) ); #if defined(POLARSSL_HAVE_TIME) t = time( NULL ); *p++ = (unsigned char)( t >> 24 ); *p++ = (unsigned char)( t >> 16 ); *p++ = (unsigned char)( t >> 8 ); *p++ = (unsigned char)( t ); SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) ); #else if( ( ret = ssl->f_rng( ssl->p_rng, p, 4 ) ) != 0 ) return( ret ); p += 4; #endif /* POLARSSL_HAVE_TIME */ if( ( ret = ssl->f_rng( ssl->p_rng, p, 28 ) ) != 0 ) return( ret ); p += 28; memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 ); SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 ); /* * Resume is 0 by default, see ssl_handshake_init(). * It may be already set to 1 by ssl_parse_session_ticket_ext(). * If not, try looking up session ID in our cache. */ if( ssl->handshake->resume == 0 && #if defined(POLARSSL_SSL_RENEGOTIATION) ssl->renego_status == SSL_INITIAL_HANDSHAKE && #endif ssl->session_negotiate->length != 0 && ssl->f_get_cache != NULL && ssl->f_get_cache( ssl->p_get_cache, ssl->session_negotiate ) == 0 ) { SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) ); ssl->handshake->resume = 1; } 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(POLARSSL_HAVE_TIME) ssl->session_negotiate->start = time( NULL ); #endif #if defined(POLARSSL_SSL_SESSION_TICKETS) if( ssl->handshake->new_session_ticket != 0 ) { ssl->session_negotiate->length = n = 0; memset( ssl->session_negotiate->id, 0, 32 ); } else #endif /* POLARSSL_SSL_SESSION_TICKETS */ { ssl->session_negotiate->length = n = 32; if( ( ret = ssl->f_rng( ssl->p_rng, ssl->session_negotiate->id, n ) ) != 0 ) return( ret ); } } else { /* * Resuming a session */ n = ssl->session_negotiate->length; ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC; if( ( ret = ssl_derive_keys( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "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->length; memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->length ); p += ssl->session_negotiate->length; SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) ); SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n ); 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 ); SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s", ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) ); SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X", ssl->session_negotiate->compression ) ); /* * First write extensions, then the total length */ ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH) ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_SSL_TRUNCATED_HMAC) ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC) ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET) ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_SSL_SESSION_TICKETS) ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C) ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif #if defined(POLARSSL_SSL_ALPN) ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #endif SSL_DEBUG_MSG( 3, ( "server 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 = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_HELLO; ret = ssl_write_record( ssl ); SSL_DEBUG_MSG( 2, ( "<= write server hello" ) ); return( ret ); } #if !defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) static int ssl_write_certificate_request( ssl_context *ssl ) { const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ) { SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) ); ssl->state++; return( 0 ); } SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } #else static int ssl_write_certificate_request( ssl_context *ssl ) { int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE; const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; size_t dn_size, total_dn_size; /* excluding length bytes */ size_t ct_len, sa_len; /* including length bytes */ unsigned char *buf, *p; const x509_crt *crt; SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) ); ssl->state++; if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK || ssl->authmode == SSL_VERIFY_NONE ) { 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(POLARSSL_RSA_C) p[1 + ct_len++] = SSL_CERT_TYPE_RSA_SIGN; #endif #if defined(POLARSSL_ECDSA_C) p[1 + ct_len++] = SSL_CERT_TYPE_ECDSA_SIGN; #endif p[0] = (unsigned char) ct_len++; p += ct_len; sa_len = 0; #if defined(POLARSSL_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 == SSL_MINOR_VERSION_3 ) { /* * Only use current running hash algorithm that is already required * for requested ciphersuite. */ ssl->handshake->verify_sig_alg = SSL_HASH_SHA256; if( ssl->transform_negotiate->ciphersuite_info->mac == POLARSSL_MD_SHA384 ) { ssl->handshake->verify_sig_alg = SSL_HASH_SHA384; } /* * Supported signature algorithms */ #if defined(POLARSSL_RSA_C) p[2 + sa_len++] = ssl->handshake->verify_sig_alg; p[2 + sa_len++] = SSL_SIG_RSA; #endif #if defined(POLARSSL_ECDSA_C) p[2 + sa_len++] = ssl->handshake->verify_sig_alg; p[2 + sa_len++] = SSL_SIG_ECDSA; #endif p[0] = (unsigned char)( sa_len >> 8 ); p[1] = (unsigned char)( sa_len ); sa_len += 2; p += sa_len; } #endif /* POLARSSL_SSL_PROTO_TLS1_2 */ /* * DistinguishedName certificate_authorities<0..2^16-1>; * opaque DistinguishedName<1..2^16-1>; */ p += 2; crt = ssl->ca_chain; total_dn_size = 0; while( crt != NULL && crt->version != 0 ) { if( p - buf > 4096 ) break; dn_size = crt->subject_raw.len; *p++ = (unsigned char)( dn_size >> 8 ); *p++ = (unsigned char)( dn_size ); memcpy( p, crt->subject_raw.p, dn_size ); p += dn_size; SSL_DEBUG_BUF( 3, "requested DN", p, dn_size ); total_dn_size += 2 + dn_size; crt = crt->next; } ssl->out_msglen = p - buf; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = 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 = ssl_write_record( ssl ); SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) ); return( ret ); } #endif /* !POLARSSL_KEY_EXCHANGE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) static int ssl_get_ecdh_params_from_cert( ssl_context *ssl ) { int ret; if( ! pk_can_do( ssl_own_key( ssl ), POLARSSL_PK_ECKEY ) ) { SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) ); return( POLARSSL_ERR_SSL_PK_TYPE_MISMATCH ); } if( ( ret = ecdh_get_params( &ssl->handshake->ecdh_ctx, pk_ec( *ssl_own_key( ssl ) ), POLARSSL_ECDH_OURS ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ecdh_get_params" ), ret ); return( ret ); } return( 0 ); } #endif /* POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ static int ssl_write_server_key_exchange( ssl_context *ssl ) { int ret; size_t n = 0; const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; #if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) unsigned char *p = ssl->out_msg + 4; unsigned char *dig_signed = p; size_t dig_signed_len = 0, len; ((void) dig_signed); ((void) dig_signed_len); #endif SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) ); #if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ) { SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) ); ssl->state++; return( 0 ); } #endif #if defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_ECDSA ) { ssl_get_ecdh_params_from_cert( ssl ); SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) ); ssl->state++; return( 0 ); } #endif #if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ) { /* TODO: Support identity hints */ *(p++) = 0x00; *(p++) = 0x00; n += 2; } #endif /* POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED || POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ) { /* * 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 = mpi_copy( &ssl->handshake->dhm_ctx.P, &ssl->dhm_P ) ) != 0 || ( ret = mpi_copy( &ssl->handshake->dhm_ctx.G, &ssl->dhm_G ) ) != 0 ) { SSL_DEBUG_RET( 1, "mpi_copy", ret ); return( ret ); } if( ( ret = dhm_make_params( &ssl->handshake->dhm_ctx, (int) mpi_size( &ssl->handshake->dhm_ctx.P ), p, &len, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_make_params", ret ); return( ret ); } dig_signed = p; dig_signed_len = len; p += len; n += len; SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X ); SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P ); SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G ); SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX ); } #endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE__SOME__ECDHE_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ) { /* * Ephemeral ECDH parameters: * * struct { * ECParameters curve_params; * ECPoint public; * } ServerECDHParams; */ const ecp_curve_info **curve = NULL; #if defined(POLARSSL_SSL_SET_CURVES) const ecp_group_id *gid; /* Match our preference list against the offered curves */ for( gid = ssl->curve_list; *gid != POLARSSL_ECP_DP_NONE; gid++ ) for( curve = ssl->handshake->curves; *curve != NULL; curve++ ) if( (*curve)->grp_id == *gid ) goto curve_matching_done; curve_matching_done: #else curve = ssl->handshake->curves; #endif if( *curve == NULL ) { SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) ); return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN ); } SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) ); if( ( ret = ecp_use_known_dp( &ssl->handshake->ecdh_ctx.grp, (*curve)->grp_id ) ) != 0 ) { SSL_DEBUG_RET( 1, "ecp_use_known_dp", ret ); return( ret ); } if( ( ret = ecdh_make_params( &ssl->handshake->ecdh_ctx, &len, p, SSL_MAX_CONTENT_LEN - n, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "ecdh_make_params", ret ); return( ret ); } dig_signed = p; dig_signed_len = len; p += len; n += len; SSL_DEBUG_ECP( 3, "ECDH: Q ", &ssl->handshake->ecdh_ctx.Q ); } #endif /* POLARSSL_KEY_EXCHANGE__SOME__ECDHE_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA ) { size_t signature_len = 0; unsigned int hashlen = 0; unsigned char hash[64]; md_type_t md_alg = POLARSSL_MD_NONE; /* * Choose hash algorithm. NONE means MD5 + SHA1 here. */ #if defined(POLARSSL_SSL_PROTO_TLS1_2) if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { md_alg = ssl_md_alg_from_hash( ssl->handshake->sig_alg ); if( md_alg == POLARSSL_MD_NONE ) { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } } else #endif /* POLARSSL_SSL_PROTO_TLS1_2 */ #if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \ defined(POLARSSL_SSL_PROTO_TLS1_1) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA ) { md_alg = POLARSSL_MD_SHA1; } else #endif { md_alg = POLARSSL_MD_NONE; } /* * Compute the hash to be signed */ #if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \ defined(POLARSSL_SSL_PROTO_TLS1_1) if( md_alg == POLARSSL_MD_NONE ) { md5_context md5; sha1_context sha1; md5_init( &md5 ); sha1_init( &sha1 ); /* * 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); */ md5_starts( &md5 ); md5_update( &md5, ssl->handshake->randbytes, 64 ); md5_update( &md5, dig_signed, dig_signed_len ); md5_finish( &md5, hash ); sha1_starts( &sha1 ); sha1_update( &sha1, ssl->handshake->randbytes, 64 ); sha1_update( &sha1, dig_signed, dig_signed_len ); sha1_finish( &sha1, hash + 16 ); hashlen = 36; md5_free( &md5 ); sha1_free( &sha1 ); } else #endif /* POLARSSL_SSL_PROTO_SSL3 || POLARSSL_SSL_PROTO_TLS1 || \ POLARSSL_SSL_PROTO_TLS1_1 */ #if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \ defined(POLARSSL_SSL_PROTO_TLS1_2) if( md_alg != POLARSSL_MD_NONE ) { md_context_t ctx; const md_info_t *md_info = md_info_from_type( md_alg ); 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 = md_init_ctx( &ctx, md_info ) ) != 0 ) { SSL_DEBUG_RET( 1, "md_init_ctx", ret ); return( ret ); } md_starts( &ctx ); md_update( &ctx, ssl->handshake->randbytes, 64 ); md_update( &ctx, dig_signed, dig_signed_len ); md_finish( &ctx, hash ); md_free( &ctx ); } else #endif /* POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 || \ POLARSSL_SSL_PROTO_TLS1_2 */ { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen != 0 ? hashlen : (unsigned int) ( md_get_size( md_info_from_type( md_alg ) ) ) ); /* * Make the signature */ if( ssl_own_key( ssl ) == NULL ) { SSL_DEBUG_MSG( 1, ( "got no private key" ) ); return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED ); } #if defined(POLARSSL_SSL_PROTO_TLS1_2) if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { *(p++) = ssl->handshake->sig_alg; *(p++) = ssl_sig_from_pk( ssl_own_key( ssl ) ); n += 2; } #endif /* POLARSSL_SSL_PROTO_TLS1_2 */ if( ( ret = pk_sign( ssl_own_key( ssl ), md_alg, hash, hashlen, p + 2 , &signature_len, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "pk_sign", ret ); return( ret ); } *(p++) = (unsigned char)( signature_len >> 8 ); *(p++) = (unsigned char)( signature_len ); n += 2; SSL_DEBUG_BUF( 3, "my signature", p, signature_len ); p += signature_len; n += signature_len; } #endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */ ssl->out_msglen = 4 + n; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_KEY_EXCHANGE; ssl->state++; if( ( ret = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) ); return( 0 ); } static int ssl_write_server_hello_done( ssl_context *ssl ) { int ret; SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) ); ssl->out_msglen = 4; ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = SSL_HS_SERVER_HELLO_DONE; ssl->state++; #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM ) ssl_send_flight_completed( ssl ); #endif if( ( ret = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) ); return( 0 ); } #if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) static int ssl_parse_client_dh_public( ssl_context *ssl, unsigned char **p, const unsigned char *end ) { int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE; size_t n; /* * Receive G^Y mod P, premaster = (G^Y)^X mod P */ if( *p + 2 > end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } n = ( (*p)[0] << 8 ) | (*p)[1]; *p += 2; if( *p + n > end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_read_public", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } *p += n; SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY ); return( ret ); } #endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED) static int ssl_parse_encrypted_pms( ssl_context *ssl, const unsigned char *p, const unsigned char *end, size_t pms_offset ) { int ret; size_t len = pk_get_len( ssl_own_key( ssl ) ); 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; if( ! pk_can_do( ssl_own_key( ssl ), POLARSSL_PK_RSA ) ) { SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) ); return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Decrypt the premaster using own private RSA key */ #if defined(POLARSSL_SSL_PROTO_TLS1) || defined(POLARSSL_SSL_PROTO_TLS1_1) || \ defined(POLARSSL_SSL_PROTO_TLS1_2) if( ssl->minor_ver != SSL_MINOR_VERSION_0 ) { if( *p++ != ( ( len >> 8 ) & 0xFF ) || *p++ != ( ( len ) & 0xFF ) ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } } #endif if( p + len != end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } ssl_write_version( ssl->handshake->max_major_ver, ssl->handshake->max_minor_ver, ssl->transport, ver ); /* * 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. * Also, avoid data-dependant branches here to protect against * timing-based variants. */ ret = ssl->f_rng( ssl->p_rng, fake_pms, sizeof( fake_pms ) ); if( ret != 0 ) return( ret ); ret = pk_decrypt( ssl_own_key( ssl ), p, len, peer_pms, &ssl->handshake->pmslen, sizeof( peer_pms ), ssl->f_rng, ssl->p_rng ); ret |= ssl->handshake->pmslen - 48; ret |= peer_pms[0] - ver[0]; ret |= peer_pms[1] - ver[1]; #if defined(POLARSSL_SSL_DEBUG_ALL) if( ret != 0 ) SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); #endif if( sizeof( ssl->handshake->premaster ) < pms_offset || sizeof( ssl->handshake->premaster ) - pms_offset < 48 ) { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } ssl->handshake->pmslen = 48; mask = (unsigned char)( - ( ret != 0 ) ); /* ret ? 0xff : 0x00 */ for( i = 0; i < ssl->handshake->pmslen; i++ ) pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] ); return( 0 ); } #endif /* POLARSSL_KEY_EXCHANGE_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED) static int ssl_parse_client_psk_identity( ssl_context *ssl, unsigned char **p, const unsigned char *end ) { int ret = 0; size_t n; if( ssl->f_psk == NULL && ( ssl->psk == NULL || ssl->psk_identity == NULL || ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) ) { SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) ); return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED ); } /* * Receive client pre-shared key identity name */ if( *p + 2 > end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } n = ( (*p)[0] << 8 ) | (*p)[1]; *p += 2; if( n < 1 || n > 65535 || *p + n > end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->f_psk != NULL ) { if( ssl->f_psk( ssl->p_psk, ssl, *p, n ) != 0 ) ret = POLARSSL_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->psk_identity_len || safer_memcmp( ssl->psk_identity, *p, n ) != 0 ) { ret = POLARSSL_ERR_SSL_UNKNOWN_IDENTITY; } } if( ret == POLARSSL_ERR_SSL_UNKNOWN_IDENTITY ) { SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n ); if( ( ret = ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL, SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY ) ) != 0 ) { return( ret ); } return( POLARSSL_ERR_SSL_UNKNOWN_IDENTITY ); } *p += n; return( 0 ); } #endif /* POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED */ static int ssl_parse_client_key_exchange( ssl_context *ssl ) { int ret; const ssl_ciphersuite_t *ciphersuite_info; unsigned char *p, *end; ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) ); if( ( ret = ssl_read_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_read_record", ret ); return( ret ); } p = ssl->in_msg + ssl_hs_hdr_len( ssl ); end = ssl->in_msg + ssl->in_hslen; if( ssl->in_msgtype != SSL_MSG_HANDSHAKE ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ssl->in_msg[0] != SSL_HS_CLIENT_KEY_EXCHANGE ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } #if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_RSA ) { if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret ); return( ret ); } if( p != end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } ssl->handshake->pmslen = POLARSSL_PREMASTER_SIZE; if( ( ret = dhm_calc_secret( &ssl->handshake->dhm_ctx, ssl->handshake->premaster, &ssl->handshake->pmslen, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "dhm_calc_secret", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS ); } SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K ); } else #endif /* POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_RSA || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_ECDSA ) { if( ( ret = ecdh_read_public( &ssl->handshake->ecdh_ctx, p, end - p) ) != 0 ) { SSL_DEBUG_RET( 1, "ecdh_read_public", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } SSL_DEBUG_ECP( 3, "ECDH: Qp ", &ssl->handshake->ecdh_ctx.Qp ); if( ( ret = ecdh_calc_secret( &ssl->handshake->ecdh_ctx, &ssl->handshake->pmslen, ssl->handshake->premaster, POLARSSL_MPI_MAX_SIZE, ssl->f_rng, ssl->p_rng ) ) != 0 ) { SSL_DEBUG_RET( 1, "ecdh_calc_secret", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS ); } SSL_DEBUG_MPI( 3, "ECDH: z ", &ssl->handshake->ecdh_ctx.z ); } else #endif /* POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED || POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( p != end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* POLARSSL_KEY_EXCHANGE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret ); return( ret ); } if( ( ret = ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret ); return( ret ); } if( p != end ) { SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE ); } if( ( ret = ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK ) { if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret ); return( ret ); } if( ( ret = ecdh_read_public( &ssl->handshake->ecdh_ctx, p, end - p ) ) != 0 ) { SSL_DEBUG_RET( 1, "ecdh_read_public", ret ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP ); } SSL_DEBUG_ECP( 3, "ECDH: Qp ", &ssl->handshake->ecdh_ctx.Qp ); if( ( ret = ssl_psk_derive_premaster( ssl, ciphersuite_info->key_exchange ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_psk_derive_premaster", ret ); return( ret ); } } else #endif /* POLARSSL_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA ) { if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 ) { SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret ); return( ret ); } } else #endif /* POLARSSL_KEY_EXCHANGE_RSA_ENABLED */ { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } if( ( ret = ssl_derive_keys( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_derive_keys", ret ); return( ret ); } ssl->state++; SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) ); return( 0 ); } #if !defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) static int ssl_parse_certificate_verify( ssl_context *ssl ) { const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) ); if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK ) { SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } #else static int ssl_parse_certificate_verify( ssl_context *ssl ) { int ret = POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE; size_t i, sig_len; unsigned char hash[48]; unsigned char *hash_start = hash; size_t hashlen; #if defined(POLARSSL_SSL_PROTO_TLS1_2) pk_type_t pk_alg; #endif md_type_t md_alg; const ssl_ciphersuite_t *ciphersuite_info = ssl->transform_negotiate->ciphersuite_info; SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) ); if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDHE_PSK || ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_DHE_PSK || ssl->session_negotiate->peer_cert == NULL ) { SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } /* Needs to be done before read_record() to exclude current message */ ssl->handshake->calc_verify( ssl, hash ); if( ( ret = ssl_read_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_read_record", ret ); return( ret ); } ssl->state++; if( ssl->in_msgtype != SSL_MSG_HANDSHAKE || ssl->in_msg[0] != SSL_HS_CERTIFICATE_VERIFY ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } i = ssl_hs_hdr_len( ssl ); /* * struct { * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only * opaque signature<0..2^16-1>; * } DigitallySigned; */ #if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1) || \ defined(POLARSSL_SSL_PROTO_TLS1_1) if( ssl->minor_ver != SSL_MINOR_VERSION_3 ) { md_alg = POLARSSL_MD_NONE; hashlen = 36; /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */ if( pk_can_do( &ssl->session_negotiate->peer_cert->pk, POLARSSL_PK_ECDSA ) ) { hash_start += 16; hashlen -= 16; md_alg = POLARSSL_MD_SHA1; } } else #endif /* POLARSSL_SSL_PROTO_SSL3 || POLARSSL_SSL_PROTO_TLS1 || POLARSSL_SSL_PROTO_TLS1_1 */ #if defined(POLARSSL_SSL_PROTO_TLS1_2) if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { if( i + 2 > ssl->in_hslen ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* * Hash */ if( ssl->in_msg[i] != ssl->handshake->verify_sig_alg ) { SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg" " for verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } md_alg = ssl_md_alg_from_hash( ssl->handshake->verify_sig_alg ); /* Info from md_alg will be used instead */ hashlen = 0; i++; /* * Signature */ if( ( pk_alg = ssl_pk_alg_from_sig( ssl->in_msg[i] ) ) == POLARSSL_PK_NONE ) { SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg" " for verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* * Check the certificate's key type matches the signature alg */ if( ! pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) ) { SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } i++; } else #endif /* POLARSSL_SSL_PROTO_TLS1_2 */ { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } if( i + 2 > ssl->in_hslen ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_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 ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } if( ( ret = pk_verify( &ssl->session_negotiate->peer_cert->pk, md_alg, hash_start, hashlen, ssl->in_msg + i, sig_len ) ) != 0 ) { SSL_DEBUG_RET( 1, "pk_verify", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) ); return( ret ); } #endif /* !POLARSSL_KEY_EXCHANGE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED */ #if defined(POLARSSL_SSL_SESSION_TICKETS) static int ssl_write_new_session_ticket( ssl_context *ssl ) { int ret; size_t tlen; uint32_t lifetime = (uint32_t) ssl->ticket_lifetime; SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) ); ssl->out_msgtype = SSL_MSG_HANDSHAKE; ssl->out_msg[0] = 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 */ ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF; ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF; ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF; ssl->out_msg[7] = ( lifetime ) & 0xFF; if( ( ret = ssl_write_ticket( ssl, &tlen ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_ticket", ret ); tlen = 0; } ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF ); ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF ); 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 = ssl_write_record( ssl ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_write_record", ret ); return( ret ); } SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) ); return( 0 ); } #endif /* POLARSSL_SSL_SESSION_TICKETS */ /* * SSL handshake -- server side -- single step */ int ssl_handshake_server_step( ssl_context *ssl ) { int ret = 0; if( ssl->state == SSL_HANDSHAKE_OVER ) return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) ); if( ( ret = ssl_flush_output( ssl ) ) != 0 ) return( ret ); #if defined(POLARSSL_SSL_PROTO_DTLS) if( ssl->transport == SSL_TRANSPORT_DATAGRAM && ssl->handshake != NULL && ssl->handshake->retransmit_state == SSL_RETRANS_SENDING ) { if( ( ret = ssl_resend( ssl ) ) != 0 ) return( ret ); } #endif switch( ssl->state ) { case SSL_HELLO_REQUEST: ssl->state = SSL_CLIENT_HELLO; break; /* * <== ClientHello */ case SSL_CLIENT_HELLO: ret = ssl_parse_client_hello( ssl ); break; #if defined(POLARSSL_SSL_PROTO_DTLS) case SSL_SERVER_HELLO_VERIFY_REQUEST_SENT: return( POLARSSL_ERR_SSL_HELLO_VERIFY_REQUIRED ); #endif /* * ==> ServerHello * Certificate * ( ServerKeyExchange ) * ( CertificateRequest ) * ServerHelloDone */ case SSL_SERVER_HELLO: ret = ssl_write_server_hello( ssl ); break; case SSL_SERVER_CERTIFICATE: ret = ssl_write_certificate( ssl ); break; case SSL_SERVER_KEY_EXCHANGE: ret = ssl_write_server_key_exchange( ssl ); break; case SSL_CERTIFICATE_REQUEST: ret = ssl_write_certificate_request( ssl ); break; case SSL_SERVER_HELLO_DONE: ret = ssl_write_server_hello_done( ssl ); break; /* * <== ( Certificate/Alert ) * ClientKeyExchange * ( CertificateVerify ) * ChangeCipherSpec * Finished */ case SSL_CLIENT_CERTIFICATE: ret = ssl_parse_certificate( ssl ); break; case SSL_CLIENT_KEY_EXCHANGE: ret = ssl_parse_client_key_exchange( ssl ); break; case SSL_CERTIFICATE_VERIFY: ret = ssl_parse_certificate_verify( ssl ); break; case SSL_CLIENT_CHANGE_CIPHER_SPEC: ret = ssl_parse_change_cipher_spec( ssl ); break; case SSL_CLIENT_FINISHED: ret = ssl_parse_finished( ssl ); break; /* * ==> ( NewSessionTicket ) * ChangeCipherSpec * Finished */ case SSL_SERVER_CHANGE_CIPHER_SPEC: #if defined(POLARSSL_SSL_SESSION_TICKETS) if( ssl->handshake->new_session_ticket != 0 ) ret = ssl_write_new_session_ticket( ssl ); else #endif ret = ssl_write_change_cipher_spec( ssl ); break; case SSL_SERVER_FINISHED: ret = ssl_write_finished( ssl ); break; case SSL_FLUSH_BUFFERS: SSL_DEBUG_MSG( 2, ( "handshake: done" ) ); ssl->state = SSL_HANDSHAKE_WRAPUP; break; case SSL_HANDSHAKE_WRAPUP: ssl_handshake_wrapup( ssl ); break; default: SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) ); return( POLARSSL_ERR_SSL_BAD_INPUT_DATA ); } return( ret ); } #endif /* POLARSSL_SSL_SRV_C */