/* * 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 "polarssl/config.h" #else #include POLARSSL_CONFIG_FILE #endif #if defined(POLARSSL_SSL_SRV_C) #include "polarssl/debug.h" #include "polarssl/ssl.h" #include #if defined(POLARSSL_ECP_C) #include "polarssl/ecp.h" #endif #if defined(POLARSSL_PLATFORM_C) #include "polarssl/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_ctr ) - 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 ) */ sha256_hmac( ssl->ticket_keys->mac_key, 16, start, p - start, p, 0 ); 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 */ sha256_hmac( ssl->ticket_keys->mac_key, 16, buf, len - 32, computed_mac, 0 ); 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_SERVER_NAME_INDICATION) /* * Wrapper around f_sni, allowing use of ssl_set_own_cert() but * making it act on ssl->hanshake->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->renegotiation != 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) /* * Status of the implementation of signature-algorithms extension: * * Currently, we are only considering the signature-algorithm extension * to pick a ciphersuite which allows us to send the ServerKeyExchange * message with a signature-hash combination that the user allows. * * We do *not* check whether all certificates in our certificate * chain are signed with an allowed signature-hash pair. * This needs to be done at a later stage. * */ static int ssl_parse_signature_algorithms_ext( 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; md_type_t md_cur; pk_type_t sig_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 ); } /* Currently we only guarantee signing the ServerKeyExchange message according * to the constraints specified in this extension (see above), so it suffices * to remember only one suitable hash for each possible signature algorithm. * * This will change when we also consider certificate signatures, * in which case we will need to remember the whole signature-hash * pair list from the extension. */ for( p = buf + 2; p < end; p += 2 ) { /* Silently ignore unknown signature or hash algorithms. */ if( (sig_cur = ssl_pk_alg_from_sig( p[1] ) ) == POLARSSL_PK_NONE ) { SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: unknown sig alg encoding %d", p[1] ) ); continue; } /* Check if we support the hash the user proposes */ md_cur = ssl_md_alg_from_hash( p[0] ); if( md_cur == POLARSSL_MD_NONE ) { SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: " "unknown hash alg encoding %d", p[0] ) ); continue; } if( ssl_check_sig_hash( md_cur ) == 0 ) { ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur ); SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: match sig %d and hash %d", sig_cur, md_cur ) ); } else { SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: hash alg %d not supported", md_cur ) ); } } 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 + 1; 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->renegotiation != 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 ); int flags; #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, &flags ) != 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; #if defined(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) pk_type_t sig_type; #endif 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( 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_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) /* If the ciphersuite requires signing, check whether * a suitable hash algorithm is present. */ if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { sig_type = ssl_get_ciphersuite_sig_alg( suite_info ); if( sig_type != POLARSSL_PK_NONE && ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == POLARSSL_MD_NONE ) { SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm " "for signature algorithm %d", sig_type ) ); return( 0 ); } } #endif /* POLARSSL_SSL_PROTO_TLS1_2 && POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */ #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->renegotiation != 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->renegotiation == SSL_RENEGOTIATION ) { 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 >> 8 ) & 0xff ) && p[2] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 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; size_t n; unsigned int ciph_len, sess_len; unsigned int comp_len; unsigned int ext_len = 0; 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; /* If there is no signature-algorithm extension present, * we need to fall back to the default values for allowed * signature-hash pairs. */ #if defined(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) int sig_hash_alg_ext_present = 0; #endif /* POLARSSL_SSL_PROTO_TLS1_2 && POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */ SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) ); #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renegotiation == 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( ( buf[0] & 0x80 ) != 0 ) return ssl_parse_client_hello_v2( ssl ); #endif SSL_DEBUG_BUF( 4, "record header", buf, 5 ); SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d", buf[0] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d", ( buf[3] << 8 ) | buf[4] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, protocol ver: [%d:%d]", buf[1], buf[2] ) ); /* * SSLv3/TLS Client Hello * * Record layer: * 0 . 0 message type * 1 . 2 protocol version * 3 . 4 message length */ /* 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( buf[0] != SSL_MSG_HANDSHAKE || buf[1] < SSL_MAJOR_VERSION_3 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } n = ( buf[3] << 8 ) | buf[4]; if( n < 45 || n > SSL_MAX_CONTENT_LEN ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE ) #endif { if( ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 ) { SSL_DEBUG_RET( 1, "ssl_fetch_input", ret ); return( ret ); } } buf = ssl->in_msg; #if defined(POLARSSL_SSL_RENEGOTIATION) if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE ) n = ssl->in_msglen; else #endif n = ssl->in_left - 5; ssl->handshake->update_checksum( ssl, buf, n ); /* * SSL layer: * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 protocol version * 6 . 9 UNIX time() * 10 . 37 random bytes * 38 . 38 session id length * 39 . 38+x session id * 39+x . 40+x ciphersuitelist length * 41+x . 40+y ciphersuitelist * 41+y . 41+y compression alg length * 42+y . 41+z compression algs * .. . .. extensions */ SSL_DEBUG_BUF( 4, "record contents", buf, n ); SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d", ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) ); SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]", buf[4], buf[5] ) ); /* * Check the handshake type and protocol version */ if( buf[0] != SSL_HS_CLIENT_HELLO ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->major_ver = buf[4]; ssl->minor_ver = buf[5]; 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; memcpy( ssl->handshake->randbytes, buf + 6, 32 ); /* * Check the handshake message length */ if( buf[1] != 0 || n != (unsigned int) 4 + ( ( buf[2] << 8 ) | buf[3] ) ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the session length */ sess_len = buf[38]; if( sess_len > 32 || sess_len > n - 42 ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } ssl->session_negotiate->length = sess_len; memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) ); memcpy( ssl->session_negotiate->id, buf + 39, ssl->session_negotiate->length ); /* * Check the ciphersuitelist length */ ciph_len = ( buf[39 + sess_len] << 8 ) | ( buf[40 + sess_len] ); if( ciph_len < 2 || ( ciph_len % 2 ) != 0 || ciph_len > n - 42 - sess_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the compression algorithms length */ comp_len = buf[41 + sess_len + ciph_len]; if( comp_len < 1 || comp_len > 16 || comp_len > n - 42 - sess_len - ciph_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } /* * Check the extension length */ if( n > 42 + sess_len + ciph_len + comp_len ) { ext_len = ( buf[42 + sess_len + ciph_len + comp_len] << 8 ) | ( buf[43 + sess_len + ciph_len + comp_len] ); if( ( ext_len > 0 && ext_len < 4 ) || n != 44 + sess_len + ciph_len + comp_len + ext_len ) { SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); SSL_DEBUG_BUF( 3, "Ext", buf + 44 + sess_len + ciph_len + comp_len, ext_len); return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO ); } } ssl->session_negotiate->compression = SSL_COMPRESS_NULL; #if defined(POLARSSL_ZLIB_SUPPORT) for( i = 0; i < comp_len; ++i ) { if( buf[42 + sess_len + ciph_len + i] == SSL_COMPRESS_DEFLATE ) { ssl->session_negotiate->compression = SSL_COMPRESS_DEFLATE; break; } } #endif SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 6, 32 ); SSL_DEBUG_BUF( 3, "client hello, session id", buf + 38, sess_len ); SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist", buf + 41 + sess_len, ciph_len ); SSL_DEBUG_BUF( 3, "client hello, compression", buf + 42 + sess_len + ciph_len, comp_len ); /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for( i = 0, p = buf + 41 + sess_len; 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->renegotiation == SSL_RENEGOTIATION ) { 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 ); } renegotiation_info_seen = 1; #endif /* POLARSSL_SSL_RENEGOTIATION */ ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION; break; } } #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 >> 8 ) & 0xff ) && p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 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 */ /* Do not parse the extensions if the protocol is SSLv3 */ #if defined(POLARSSL_SSL_PROTO_SSL3) if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) ) { #endif ext = buf + 44 + sess_len + ciph_len + comp_len; SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len ); while( ext_len ) { unsigned int ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) ); unsigned int ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) ); if( ext_size + 4 > ext_len ) { 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" ) ); ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size ); if( ret != 0 ) return( ret ); sig_hash_alg_ext_present = 1; 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_PROTO_SSL3) } #endif /* * 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->renegotiation == SSL_RENEGOTIATION && 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->renegotiation == SSL_RENEGOTIATION && 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->renegotiation == SSL_RENEGOTIATION && 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 ); } #if defined(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) /* * Try to fall back to default hash SHA1 if the client * hasn't provided any preferred signature-hash combinations. */ if( sig_hash_alg_ext_present == 0 ) { md_type_t md_default = POLARSSL_MD_SHA1; if( ssl_check_sig_hash( md_default ) != 0 ) md_default = POLARSSL_MD_NONE; ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default ); } #endif /* POLARSSL_SSL_PROTO_TLS1_2 && POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED */ /* * 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 + 41 + sess_len; 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 + 41 + sess_len; 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->in_left = 0; ssl->state++; /* Debugging-only output for testsuite */ #if defined(POLARSSL_DEBUG_C) && \ defined(POLARSSL_SSL_PROTO_TLS1_2) && \ defined(POLARSSL_KEY_EXCHANGE__WITH_CERT__ENABLED) if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { pk_type_t sig_alg = ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); if( sig_alg != POLARSSL_PK_NONE ) { md_type_t md_alg = ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_alg ); SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d", ssl_hash_from_md_alg( md_alg ) ) ); } else { SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm %d - should not happen", sig_alg ) ); } } #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->renegotiation != 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 */ 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( 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; *p++ = (unsigned char) ssl->major_ver; *p++ = (unsigned char) ssl->minor_ver; 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->renegotiation == 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 ) ); /* Do not write the extensions if the protocol is SSLv3 */ #if defined(POLARSSL_SSL_PROTO_SSL3) if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) ) { #endif /* * First write extensions, then the total length */ ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen ); ext_len += olen; #if defined(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; } #if defined(POLARSSL_SSL_PROTO_SSL3) } #endif 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_ECDH_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_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; const unsigned char * const end = ssl->out_msg + SSL_MAX_CONTENT_LEN; 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 ) { dn_size = crt->subject_raw.len; if( end < p || (size_t)( end - p ) < dn_size || (size_t)( end - p ) < 2 + dn_size ) { SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) ); break; } *p++ = (unsigned char)( dn_size >> 8 ); *p++ = (unsigned char)( dn_size ); memcpy( p, crt->subject_raw.p, dn_size ); p += dn_size; 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_ECDH_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_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 || *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]; /* * Choose hash algorithm: * - For TLS 1.2, obey signature-hash-algorithm extension to choose appropriate hash. * - For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1 (RFC 4492, Sec. 5.4) * - Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3) */ md_type_t md_alg; #if defined(POLARSSL_SSL_PROTO_TLS1_2) pk_type_t sig_alg = ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info ); if( ssl->minor_ver == SSL_MINOR_VERSION_3 ) { /* For TLS 1.2, obey signature-hash-algorithm extension * (RFC 5246, Sec. 7.4.1.4.1). */ if( sig_alg == POLARSSL_PK_NONE || ( md_alg = ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_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; } SSL_DEBUG_MSG( 3, ( "pick hash algorithm %d for signing", md_alg ) ); /* * 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_info_from_type( md_alg ) )->size ); /* * 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_hash_from_md_alg( md_alg ); *(p++) = ssl_sig_from_pk_alg( sig_alg ); 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( ( 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 fake_pms[48], peer_pms[48]; unsigned char mask; size_t i, peer_pmslen; unsigned int diff; 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 ); } /* * 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, &peer_pmslen, sizeof( peer_pms ), ssl->f_rng, ssl->p_rng ); diff = (unsigned int) ret; diff |= peer_pmslen ^ 48; diff |= peer_pms[0] ^ ssl->handshake->max_major_ver; diff |= peer_pms[1] ^ ssl->handshake->max_minor_ver; #if defined(POLARSSL_SSL_DEBUG_ALL) if( diff != 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 = diff ? 0xff : 0x00 */ /* MSVC has a warning about unary minus on unsigned, but this is * well-defined and precisely what we want to do here */ #if defined(_MSC_VER) #pragma warning( push ) #pragma warning( disable : 4146 ) #endif mask = - ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ); #if defined(_MSC_VER) #pragma warning( pop ) #endif 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( end - *p < 2 ) { 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 || n > (size_t) ( end - *p ) ) { 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; 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 ); } 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 ) { unsigned char *p = ssl->in_msg + 4; unsigned char *end = ssl->in_msg + ssl->in_hslen; 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, ssl->in_msg + 4, ssl->in_hslen - 4 ) ) != 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 ) { unsigned char *p = ssl->in_msg + 4; unsigned char *end = ssl->in_msg + ssl->in_hslen; 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 ) { unsigned char *p = ssl->in_msg + 4; unsigned char *end = ssl->in_msg + ssl->in_hslen; 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 ) { unsigned char *p = ssl->in_msg + 4; unsigned char *end = ssl->in_msg + ssl->in_hslen; 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 ) { unsigned char *p = ssl->in_msg + 4; unsigned char *end = ssl->in_msg + ssl->in_hslen; 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, ssl->in_msg + 4, ssl->in_msg + ssl->in_hslen, 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_ECDH_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \ !defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_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 sa_len, 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_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } if( ssl->session_negotiate->peer_cert == NULL ) { SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) ); ssl->state++; return( 0 ); } 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_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } if( ssl->in_msg[0] != SSL_HS_CERTIFICATE_VERIFY ) { SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) ); return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY ); } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 sig alg (TLS 1.2 only) * 4+n . 5+n signature length (n = sa_len) * 6+n . 6+n+m signature (m = sig_len) */ #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 ) { sa_len = 0; 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 ) { sa_len = 2; /* * Hash */ if( ssl->in_msg[4] != 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; /* * Signature */ if( ( pk_alg = ssl_pk_alg_from_sig( ssl->in_msg[5] ) ) == 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 ); } } else #endif /* POLARSSL_SSL_PROTO_TLS1_2 */ { SSL_DEBUG_MSG( 1, ( "should never happen" ) ); return( POLARSSL_ERR_SSL_INTERNAL_ERROR ); } sig_len = ( ssl->in_msg[4 + sa_len] << 8 ) | ssl->in_msg[5 + sa_len]; if( sa_len + sig_len + 6 != 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 + 6 + sa_len, 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_ECDH_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED && !POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_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 ); 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; /* * ==> 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 */