diff --git a/ChangeLog b/ChangeLog index 869a77c800..c26974285b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -21,6 +21,10 @@ Features last paragraph). * Add support for packing multiple records within a single datagram, enabled by default. + * Add support for buffering out-of-order handshake messages in DTLS. + The maximum amount of RAM used for this can be controlled by the + compile-time constant MBEDTLS_SSL_DTLS_MAX_BUFFERING defined + in mbedtls/config.h. API Changes * Add function mbedtls_ssl_set_datagram_packing() to configure @@ -66,6 +70,7 @@ Changes * Fix a miscalculation of the maximum record expansion in mbedtls_ssl_get_record_expansion() in case of ChachaPoly ciphersuites, or CBC ciphersuites in (D)TLS versions 1.1 or higher. Fixes #1913, #1914. + * Add support for buffering of out-of-order handshake messages. INTERNAL NOTE: need to bump soversion of libmbedtls: - added new member 'mtu' to public 'mbedtls_ssl_conf' structure diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h index 70820be56f..052aed0d3f 100644 --- a/include/mbedtls/config.h +++ b/include/mbedtls/config.h @@ -3010,6 +3010,23 @@ */ //#define MBEDTLS_SSL_OUT_CONTENT_LEN 16384 +/** \def MBEDTLS_SSL_DTLS_MAX_BUFFERING + * + * Maximum number of heap-allocated bytes for the purpose of + * DTLS handshake message reassembly and future message buffering. + * + * This should be at least 9/8 * MBEDTLSSL_IN_CONTENT_LEN + * to account for a reassembled handshake message of maximum size, + * together with its reassembly bitmap. + * + * A value of 2 * MBEDTLS_SSL_IN_CONTENT_LEN (32768 by default) + * should be sufficient for all practical situations as it allows + * to reassembly a large handshake message (such as a certificate) + * while buffering multiple smaller handshake messages. + * + */ +//#define MBEDTLS_SSL_DTLS_MAX_BUFFERING 32768 + //#define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME 86400 /**< Lifetime of session tickets (if enabled) */ //#define MBEDTLS_PSK_MAX_LEN 32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */ //#define MBEDTLS_SSL_COOKIE_TIMEOUT 60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */ diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h index da4b688287..83849a5645 100644 --- a/include/mbedtls/ssl.h +++ b/include/mbedtls/ssl.h @@ -121,6 +121,7 @@ #define MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH -0x6600 /**< Couldn't set the hash for verifying CertificateVerify */ #define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -0x6580 /**< Internal-only message signaling that further message-processing should be done */ #define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS -0x6500 /**< The asynchronous operation is not completed yet. */ +#define MBEDTLS_ERR_SSL_EARLY_MESSAGE -0x6480 /**< Internal-only message signaling that a message arrived early. */ /* * Various constants @@ -242,6 +243,14 @@ #define MBEDTLS_SSL_OUT_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN #endif +/* + * Maximum number of heap-allocated bytes for the purpose of + * DTLS handshake message reassembly and future message buffering. + */ +#if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING) +#define MBEDTLS_SSL_DTLS_MAX_BUFFERING 32768 +#endif + /* \} name SECTION: Module settings */ /* @@ -1022,14 +1031,14 @@ struct mbedtls_ssl_context int renego_records_seen; /*!< Records since renego request, or with DTLS, number of retransmissions of request if renego_max_records is < 0 */ -#endif +#endif /* MBEDTLS_SSL_RENEGOTIATION */ int major_ver; /*!< equal to MBEDTLS_SSL_MAJOR_VERSION_3 */ int minor_ver; /*!< either 0 (SSL3) or 1 (TLS1.0) */ #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT) unsigned badmac_seen; /*!< records with a bad MAC received */ -#endif +#endif /* MBEDTLS_SSL_DTLS_BADMAC_LIMIT */ mbedtls_ssl_send_t *f_send; /*!< Callback for network send */ mbedtls_ssl_recv_t *f_recv; /*!< Callback for network receive */ @@ -1085,11 +1094,11 @@ struct mbedtls_ssl_context uint16_t in_epoch; /*!< DTLS epoch for incoming records */ size_t next_record_offset; /*!< offset of the next record in datagram (equal to in_left if none) */ -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) uint64_t in_window_top; /*!< last validated record seq_num */ uint64_t in_window; /*!< bitmask for replay detection */ -#endif +#endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */ size_t in_hslen; /*!< current handshake message length, including the handshake header */ @@ -1121,14 +1130,14 @@ struct mbedtls_ssl_context #if defined(MBEDTLS_SSL_PROTO_DTLS) uint16_t mtu; /*!< path mtu, used to fragment outgoing messages */ -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ #if defined(MBEDTLS_ZLIB_SUPPORT) unsigned char *compress_buf; /*!< zlib data buffer */ -#endif +#endif /* MBEDTLS_ZLIB_SUPPORT */ #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING) signed char split_done; /*!< current record already splitted? */ -#endif +#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */ /* * PKI layer @@ -1141,11 +1150,11 @@ struct mbedtls_ssl_context #if defined(MBEDTLS_X509_CRT_PARSE_C) char *hostname; /*!< expected peer CN for verification (and SNI if available) */ -#endif +#endif /* MBEDTLS_X509_CRT_PARSE_C */ #if defined(MBEDTLS_SSL_ALPN) const char *alpn_chosen; /*!< negotiated protocol */ -#endif +#endif /* MBEDTLS_SSL_ALPN */ /* * Information for DTLS hello verify @@ -1153,7 +1162,7 @@ struct mbedtls_ssl_context #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C) unsigned char *cli_id; /*!< transport-level ID of the client */ size_t cli_id_len; /*!< length of cli_id */ -#endif +#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */ /* * Secure renegotiation @@ -1165,7 +1174,7 @@ struct mbedtls_ssl_context size_t verify_data_len; /*!< length of verify data stored */ char own_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!< previous handshake verify data */ char peer_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!< previous handshake verify data */ -#endif +#endif /* MBEDTLS_SSL_RENEGOTIATION */ }; #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) @@ -1400,8 +1409,9 @@ void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl, * encapsulation and encryption/authentication if any. * * \note This can be called at any point during the connection, for - * example when a PMTU estimate becomes available from other - * sources, such as lower (or higher) protocol layers. + * example when a Path Maximum Transfer Unit (PMTU) + * estimate becomes available from other sources, + * such as lower (or higher) protocol layers. * * \note This setting only controls the size of the packets we send, * and does not restrict the size of the datagrams we're diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h index 65b1fc9e75..4b4417a5fa 100644 --- a/include/mbedtls/ssl_internal.h +++ b/include/mbedtls/ssl_internal.h @@ -155,6 +155,9 @@ #define MBEDTLS_SSL_OUT_PAYLOAD_LEN ( MBEDTLS_SSL_PAYLOAD_OVERHEAD + \ ( MBEDTLS_SSL_OUT_CONTENT_LEN ) ) +/* The maximum number of buffered handshake messages. */ +#define MBEDTLS_SSL_MAX_BUFFERED_HS 4 + /* Maximum length we can advertise as our max content length for RFC 6066 max_fragment_length extension negotiation purposes (the lesser of both sizes, if they are unequal.) @@ -294,8 +297,6 @@ struct mbedtls_ssl_handshake_params unsigned char verify_cookie_len; /*!< Cli: cookie length Srv: flag for sending a cookie */ - unsigned char *hs_msg; /*!< Reassembled handshake message */ - uint32_t retransmit_timeout; /*!< Current value of timeout */ unsigned char retransmit_state; /*!< Retransmission state */ mbedtls_ssl_flight_item *flight; /*!< Current outgoing flight */ @@ -307,6 +308,33 @@ struct mbedtls_ssl_handshake_params resending messages */ unsigned char alt_out_ctr[8]; /*!< Alternative record epoch/counter for resending messages */ + + struct + { + size_t total_bytes_buffered; /*!< Cumulative size of heap allocated + * buffers used for message buffering. */ + + uint8_t seen_ccs; /*!< Indicates if a CCS message has + * been seen in the current flight. */ + + struct mbedtls_ssl_hs_buffer + { + unsigned is_valid : 1; + unsigned is_fragmented : 1; + unsigned is_complete : 1; + unsigned char *data; + size_t data_len; + } hs[MBEDTLS_SSL_MAX_BUFFERED_HS]; + + struct + { + unsigned char *data; + size_t len; + unsigned epoch; + } future_record; + + } buffering; + uint16_t mtu; /*!< Handshake mtu, used to fragment outgoing messages */ #endif /* MBEDTLS_SSL_PROTO_DTLS */ @@ -366,6 +394,8 @@ struct mbedtls_ssl_handshake_params #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ }; +typedef struct mbedtls_ssl_hs_buffer mbedtls_ssl_hs_buffer; + /* * This structure contains a full set of runtime transform parameters * either in negotiation or active. @@ -480,7 +510,6 @@ int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl ); void mbedtls_ssl_reset_checksum( mbedtls_ssl_context *ssl ); int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl ); -int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl ); int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl ); int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ); void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ); @@ -492,7 +521,10 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ); * of the logic of (D)TLS from the implementation * of the secure transport. * - * \param ssl SSL context to use + * \param ssl The SSL context to use. + * \param update_hs_digest This indicates if the handshake digest + * should be automatically updated in case + * a handshake message is found. * * \return 0 or non-zero error code. * @@ -558,7 +590,8 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ); * following the above definition. * */ -int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ); +int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl, + unsigned update_hs_digest ); int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want ); int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl ); diff --git a/library/error.c b/library/error.c index 774244b454..6c88689190 100644 --- a/library/error.c +++ b/library/error.c @@ -515,6 +515,8 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen ) mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that further message-processing should be done" ); if( use_ret == -(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) ) mbedtls_snprintf( buf, buflen, "SSL - The asynchronous operation is not completed yet" ); + if( use_ret == -(MBEDTLS_ERR_SSL_EARLY_MESSAGE) ) + mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that a message arrived early" ); #endif /* MBEDTLS_SSL_TLS_C */ #if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C) diff --git a/library/ssl_cli.c b/library/ssl_cli.c index 82d76af79f..8385720115 100644 --- a/library/ssl_cli.c +++ b/library/ssl_cli.c @@ -1101,7 +1101,7 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret ); return( ret ); } -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) ); @@ -1500,7 +1500,7 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl ) buf = ssl->in_msg; - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { /* No alert on a read error. */ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); @@ -2349,7 +2349,7 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl ) #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -2656,7 +2656,7 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl ) return( 0 ); } - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -2808,7 +2808,7 @@ static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) ); - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -3297,7 +3297,7 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) ); - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -3414,7 +3414,7 @@ int mbedtls_ssl_handshake_client_step( mbedtls_ssl_context *ssl ) if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) return( ret ); } -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ /* Change state now, so that it is right in mbedtls_ssl_read_record(), used * by DTLS for dropping out-of-sequence ChangeCipherSpec records */ diff --git a/library/ssl_srv.c b/library/ssl_srv.c index 7101f461f3..36ca0d69f9 100644 --- a/library/ssl_srv.c +++ b/library/ssl_srv.c @@ -2397,7 +2397,7 @@ static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret ); return( ret ); } -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) ); @@ -3385,7 +3385,7 @@ static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret ); return( ret ); } -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) ); @@ -3728,7 +3728,7 @@ static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl ) } else #endif - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -4038,25 +4038,10 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl ) } /* Read the message without adding it to the checksum */ - do { - - do ret = mbedtls_ssl_read_record_layer( ssl ); - while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); - - if( ret != 0 ) - { - MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret ); - return( ret ); - } - - ret = mbedtls_ssl_handle_message_type( ssl ); - - } while( MBEDTLS_ERR_SSL_NON_FATAL == ret || - MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret ); - + ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ ); if( 0 != ret ) { - MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret ); + MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret ); return( ret ); } @@ -4279,7 +4264,7 @@ int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl ) if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) return( ret ); } -#endif +#endif /* MBEDTLS_SSL_PROTO_DTLS */ switch( ssl->state ) { diff --git a/library/ssl_tls.c b/library/ssl_tls.c index 30b2f658fc..8bd74db8d7 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -55,6 +55,7 @@ #endif static void ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl ); +static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ); /* Length of the "epoch" field in the record header */ static inline size_t ssl_ep_len( const mbedtls_ssl_context *ssl ) @@ -108,6 +109,17 @@ static void ssl_update_in_pointers( mbedtls_ssl_context *ssl, #if defined(MBEDTLS_SSL_PROTO_DTLS) +/* Forward declarations for functions related to message buffering. */ +static void ssl_buffering_free( mbedtls_ssl_context *ssl ); +static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, + uint8_t slot ); +static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ); +static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ); +static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ); +static int ssl_buffer_message( mbedtls_ssl_context *ssl ); +static int ssl_buffer_future_record( mbedtls_ssl_context *ssl ); +static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ); + static size_t ssl_get_current_mtu( const mbedtls_ssl_context *ssl ); static size_t ssl_get_maximum_datagram_size( mbedtls_ssl_context const *ssl ) { @@ -3035,7 +3047,7 @@ int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_BUF( 3, "handshake header", ssl->out_msg, 12 ); - /* Copy the handshame message content and set records fields */ + /* Copy the handshake message content and set records fields */ memcpy( ssl->out_msg + 12, p, cur_hs_frag_len ); ssl->out_msglen = cur_hs_frag_len + 12; ssl->out_msgtype = cur->type; @@ -3097,6 +3109,12 @@ void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl ) /* The next incoming flight will start with this msg_seq */ ssl->handshake->in_flight_start_seq = ssl->handshake->in_msg_seq; + /* We don't want to remember CCS's across flight boundaries. */ + ssl->handshake->buffering.seen_ccs = 0; + + /* Clear future message buffering structure. */ + ssl_buffering_free( ssl ); + /* Cancel timer */ ssl_set_timer( ssl, 0 ); @@ -3266,7 +3284,7 @@ int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl ) } #endif /* MBEDTLS_SSL_PROTO_DTLS */ - /* Update running hashes of hanshake messages seen */ + /* Update running hashes of handshake messages seen */ if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) ssl->handshake->update_checksum( ssl, ssl->out_msg, ssl->out_msglen ); } @@ -3394,12 +3412,12 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush ) #endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG( 3, ( "output record: msgtype = %d, " - "version = [%d:%d], msglen = %d", - ssl->out_hdr[0], ssl->out_hdr[1], ssl->out_hdr[2], len ) ); - + "version = [%d:%d], msglen = %d", + ssl->out_hdr[0], ssl->out_hdr[1], + ssl->out_hdr[2], len ) ); MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network", - ssl->out_hdr, protected_record_size ); + ssl->out_hdr, protected_record_size ); ssl->out_left += protected_record_size; ssl->out_hdr += protected_record_size; @@ -3432,7 +3450,9 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush ) remaining = (size_t) ret; if( remaining == 0 ) + { flush = SSL_FORCE_FLUSH; + } else { MBEDTLS_SSL_DEBUG_MSG( 2, ( "Still %u bytes available in current datagram", (unsigned) remaining ) ); @@ -3453,6 +3473,52 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush ) } #if defined(MBEDTLS_SSL_PROTO_DTLS) + +static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl ) +{ + if( ssl->in_msglen < ssl->in_hslen || + memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 || + memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 ) + { + return( 1 ); + } + return( 0 ); +} + +static uint32_t ssl_get_hs_frag_len( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[9] << 16 ) | + ( ssl->in_msg[10] << 8 ) | + ssl->in_msg[11] ); +} + +static uint32_t ssl_get_hs_frag_off( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[6] << 16 ) | + ( ssl->in_msg[7] << 8 ) | + ssl->in_msg[8] ); +} + +static int ssl_check_hs_header( mbedtls_ssl_context const *ssl ) +{ + uint32_t msg_len, frag_off, frag_len; + + msg_len = ssl_get_hs_total_len( ssl ); + frag_off = ssl_get_hs_frag_off( ssl ); + frag_len = ssl_get_hs_frag_len( ssl ); + + if( frag_off > msg_len ) + return( -1 ); + + if( frag_len > msg_len - frag_off ) + return( -1 ); + + if( frag_len + 12 > ssl->in_msglen ) + return( -1 ); + + return( 0 ); +} + /* * Mark bits in bitmask (used for DTLS HS reassembly) */ @@ -3514,162 +3580,30 @@ static int ssl_bitmask_check( unsigned char *mask, size_t len ) return( 0 ); } -/* - * Reassemble fragmented DTLS handshake messages. - * - * Use a temporary buffer for reassembly, divided in two parts: - * - the first holds the reassembled message (including handshake header), - * - the second holds a bitmask indicating which parts of the message - * (excluding headers) have been received so far. - */ -static int ssl_reassemble_dtls_handshake( mbedtls_ssl_context *ssl ) +/* msg_len does not include the handshake header */ +static size_t ssl_get_reassembly_buffer_size( size_t msg_len, + unsigned add_bitmap ) { - unsigned char *msg, *bitmask; - size_t frag_len, frag_off; - size_t msg_len = ssl->in_hslen - 12; /* Without headers */ + size_t alloc_len; - if( ssl->handshake == NULL ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "not supported outside handshake (for now)" ) ); - return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); - } + alloc_len = 12; /* Handshake header */ + alloc_len += msg_len; /* Content buffer */ - /* - * For first fragment, check size and allocate buffer - */ - if( ssl->handshake->hs_msg == NULL ) - { - size_t alloc_len; + if( add_bitmap ) + alloc_len += msg_len / 8 + ( msg_len % 8 != 0 ); /* Bitmap */ - MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d", - msg_len ) ); - - if( ssl->in_hslen > MBEDTLS_SSL_IN_CONTENT_LEN ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake message too large" ) ); - return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); - } - - /* The bitmask needs one bit per byte of message excluding header */ - alloc_len = 12 + msg_len + msg_len / 8 + ( msg_len % 8 != 0 ); - - ssl->handshake->hs_msg = mbedtls_calloc( 1, alloc_len ); - if( ssl->handshake->hs_msg == NULL ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc failed (%d bytes)", alloc_len ) ); - return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); - } - - /* Prepare final header: copy msg_type, length and message_seq, - * then add standardised fragment_offset and fragment_length */ - memcpy( ssl->handshake->hs_msg, ssl->in_msg, 6 ); - memset( ssl->handshake->hs_msg + 6, 0, 3 ); - memcpy( ssl->handshake->hs_msg + 9, - ssl->handshake->hs_msg + 1, 3 ); - } - else - { - /* Make sure msg_type and length are consistent */ - if( memcmp( ssl->handshake->hs_msg, ssl->in_msg, 4 ) != 0 ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "fragment header mismatch" ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } - } - - msg = ssl->handshake->hs_msg + 12; - bitmask = msg + msg_len; - - /* - * Check and copy current fragment - */ - frag_off = ( ssl->in_msg[6] << 16 ) | - ( ssl->in_msg[7] << 8 ) | - ssl->in_msg[8]; - frag_len = ( ssl->in_msg[9] << 16 ) | - ( ssl->in_msg[10] << 8 ) | - ssl->in_msg[11]; - - if( frag_off + frag_len > msg_len ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment offset/len: %d + %d > %d", - frag_off, frag_len, msg_len ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } - - if( frag_len + 12 > ssl->in_msglen ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment length: %d + 12 > %d", - frag_len, ssl->in_msglen ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } - - MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d", - frag_off, frag_len ) ); - - memcpy( msg + frag_off, ssl->in_msg + 12, frag_len ); - ssl_bitmask_set( bitmask, frag_off, frag_len ); - - /* - * Do we have the complete message by now? - * If yes, finalize it, else ask to read the next record. - */ - if( ssl_bitmask_check( bitmask, msg_len ) != 0 ) - { - MBEDTLS_SSL_DEBUG_MSG( 2, ( "message is not complete yet" ) ); - return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); - } - - MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake message completed" ) ); - - if( frag_len + 12 < ssl->in_msglen ) - { - /* - * We'got more handshake messages in the same record. - * This case is not handled now because no know implementation does - * that and it's hard to test, so we prefer to fail cleanly for now. - */ - MBEDTLS_SSL_DEBUG_MSG( 1, ( "last fragment not alone in its record" ) ); - return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); - } - - if( ssl->in_left > ssl->next_record_offset ) - { - /* - * We've got more data in the buffer after the current record, - * that we don't want to overwrite. Move it before writing the - * reassembled message, and adjust in_left and next_record_offset. - */ - unsigned char *cur_remain = ssl->in_hdr + ssl->next_record_offset; - unsigned char *new_remain = ssl->in_msg + ssl->in_hslen; - size_t remain_len = ssl->in_left - ssl->next_record_offset; - - /* First compute and check new lengths */ - ssl->next_record_offset = new_remain - ssl->in_hdr; - ssl->in_left = ssl->next_record_offset + remain_len; - - if( ssl->in_left > MBEDTLS_SSL_IN_BUFFER_LEN - - (size_t)( ssl->in_hdr - ssl->in_buf ) ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "reassembled message too large for buffer" ) ); - return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); - } - - memmove( new_remain, cur_remain, remain_len ); - } - - memcpy( ssl->in_msg, ssl->handshake->hs_msg, ssl->in_hslen ); - - mbedtls_free( ssl->handshake->hs_msg ); - ssl->handshake->hs_msg = NULL; - - MBEDTLS_SSL_DEBUG_BUF( 3, "reassembled handshake message", - ssl->in_msg, ssl->in_hslen ); - - return( 0 ); + return( alloc_len ); } + #endif /* MBEDTLS_SSL_PROTO_DTLS */ +static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[1] << 16 ) | + ( ssl->in_msg[2] << 8 ) | + ssl->in_msg[3] ); +} + int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) { if( ssl->in_msglen < mbedtls_ssl_hs_hdr_len( ssl ) ) @@ -3679,10 +3613,7 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) return( MBEDTLS_ERR_SSL_INVALID_RECORD ); } - ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ( - ( ssl->in_msg[1] << 16 ) | - ( ssl->in_msg[2] << 8 ) | - ssl->in_msg[3] ); + ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ssl_get_hs_total_len( ssl ); MBEDTLS_SSL_DEBUG_MSG( 3, ( "handshake message: msglen =" " %d, type = %d, hslen = %d", @@ -3694,12 +3625,26 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) int ret; unsigned int recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; + if( ssl_check_hs_header( ssl ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid handshake header" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + if( ssl->handshake != NULL && ( ( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && recv_msg_seq != ssl->handshake->in_msg_seq ) || ( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) ) { + if( recv_msg_seq > ssl->handshake->in_msg_seq ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)", + recv_msg_seq, + ssl->handshake->in_msg_seq ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + /* Retransmit only on last message from previous flight, to avoid * too many retransmissions. * Besides, No sane server ever retransmits HelloVerifyRequest */ @@ -3729,20 +3674,14 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) } /* Wait until message completion to increment in_msg_seq */ - /* Reassemble if current message is fragmented or reassembly is - * already in progress */ - if( ssl->in_msglen < ssl->in_hslen || - memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 || - memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 || - ( ssl->handshake != NULL && ssl->handshake->hs_msg != NULL ) ) + /* Message reassembly is handled alongside buffering of future + * messages; the commonality is that both handshake fragments and + * future messages cannot be forwarded immediately to the + * handshake logic layer. */ + if( ssl_hs_is_proper_fragment( ssl ) == 1 ) { MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) ); - - if( ( ret = ssl_reassemble_dtls_handshake( ssl ) ) != 0 ) - { - MBEDTLS_SSL_DEBUG_RET( 1, "ssl_reassemble_dtls_handshake", ret ); - return( ret ); - } + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); } } else @@ -3759,9 +3698,9 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ) { + mbedtls_ssl_handshake_params * const hs = ssl->handshake; - if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && - ssl->handshake != NULL ) + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && hs != NULL ) { ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen ); } @@ -3771,7 +3710,29 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake != NULL ) { - ssl->handshake->in_msg_seq++; + unsigned offset; + mbedtls_ssl_hs_buffer *hs_buf; + + /* Increment handshake sequence number */ + hs->in_msg_seq++; + + /* + * Clear up handshake buffering and reassembly structure. + */ + + /* Free first entry */ + ssl_buffering_free_slot( ssl, 0 ); + + /* Shift all other entries */ + for( offset = 0, hs_buf = &hs->buffering.hs[0]; + offset + 1 < MBEDTLS_SSL_MAX_BUFFERED_HS; + offset++, hs_buf++ ) + { + *hs_buf = *(hs_buf + 1); + } + + /* Create a fresh last entry */ + memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); } #endif } @@ -4172,7 +4133,16 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl ) } else #endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */ + { + /* Consider buffering the record. */ + if( rec_epoch == (unsigned int) ssl->in_epoch + 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Consider record for buffering" ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } } #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) @@ -4185,15 +4155,6 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl ) } #endif - /* Drop unexpected ChangeCipherSpec messages */ - if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC && - ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC && - ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ChangeCipherSpec" ) ); - return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); - } - /* Drop unexpected ApplicationData records, * except at the beginning of renegotiations */ if( ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA && @@ -4330,7 +4291,14 @@ static void ssl_handshake_wrapup_free_hs_transform( mbedtls_ssl_context *ssl ); * RFC 6347 4.1.2.7) and continue reading until a valid record is found. * */ -int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ) + +/* Helper functions for mbedtls_ssl_read_record(). */ +static int ssl_consume_current_message( mbedtls_ssl_context *ssl ); +static int ssl_get_next_record( mbedtls_ssl_context *ssl ); +static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ); + +int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl, + unsigned update_hs_digest ) { int ret; @@ -4340,17 +4308,53 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ) { do { - do ret = mbedtls_ssl_read_record_layer( ssl ); - while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); - + ret = ssl_consume_current_message( ssl ); if( ret != 0 ) - { - MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret ); return( ret ); + + if( ssl_record_is_in_progress( ssl ) == 0 ) + { +#if defined(MBEDTLS_SSL_PROTO_DTLS) + int have_buffered = 0; + + /* We only check for buffered messages if the + * current datagram is fully consumed. */ + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl_next_record_is_in_datagram( ssl ) == 0 ) + { + if( ssl_load_buffered_message( ssl ) == 0 ) + have_buffered = 1; + } + + if( have_buffered == 0 ) +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + { + ret = ssl_get_next_record( ssl ); + if( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ) + continue; + + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_get_next_record" ), ret ); + return( ret ); + } + } } ret = mbedtls_ssl_handle_message_type( ssl ); +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) + { + /* Buffer future message */ + ret = ssl_buffer_message( ssl ); + if( ret != 0 ) + return( ret ); + + ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING; + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + } while( MBEDTLS_ERR_SSL_NON_FATAL == ret || MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret ); @@ -4360,14 +4364,15 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ) return( ret ); } - if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + update_hs_digest == 1 ) { mbedtls_ssl_update_handshake_status( ssl ); } } else { - MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= reuse previously read message" ) ); + MBEDTLS_SSL_DEBUG_MSG( 2, ( "reuse previously read message" ) ); ssl->keep_current_message = 0; } @@ -4376,13 +4381,350 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ) return( 0 ); } -int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl ) +#if defined(MBEDTLS_SSL_PROTO_DTLS) +static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ) { - int ret; + if( ssl->in_left > ssl->next_record_offset ) + return( 1 ); + return( 0 ); +} + +static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + mbedtls_ssl_hs_buffer * hs_buf; + int ret = 0; + + if( hs == NULL ) + return( -1 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_messsage" ) ); + + if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC || + ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) + { + /* Check if we have seen a ChangeCipherSpec before. + * If yes, synthesize a CCS record. */ + if( !hs->buffering.seen_ccs ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "CCS not seen in the current flight" ) ); + ret = -1; + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Injecting buffered CCS message" ) ); + ssl->in_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC; + ssl->in_msglen = 1; + ssl->in_msg[0] = 1; + + /* As long as they are equal, the exact value doesn't matter. */ + ssl->in_left = 0; + ssl->next_record_offset = 0; + + hs->buffering.seen_ccs = 0; + goto exit; + } + +#if defined(MBEDTLS_DEBUG_C) + /* Debug only */ + { + unsigned offset; + for( offset = 1; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) + { + hs_buf = &hs->buffering.hs[offset]; + if( hs_buf->is_valid == 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Future message with sequence number %u %s buffered.", + hs->in_msg_seq + offset, + hs_buf->is_complete ? "fully" : "partially" ) ); + } + } + } +#endif /* MBEDTLS_DEBUG_C */ + + /* Check if we have buffered and/or fully reassembled the + * next handshake message. */ + hs_buf = &hs->buffering.hs[0]; + if( ( hs_buf->is_valid == 1 ) && ( hs_buf->is_complete == 1 ) ) + { + /* Synthesize a record containing the buffered HS message. */ + size_t msg_len = ( hs_buf->data[1] << 16 ) | + ( hs_buf->data[2] << 8 ) | + hs_buf->data[3]; + + /* Double-check that we haven't accidentally buffered + * a message that doesn't fit into the input buffer. */ + if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message has been buffered - load" ) ); + MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered handshake message (incl. header)", + hs_buf->data, msg_len + 12 ); + + ssl->in_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; + ssl->in_hslen = msg_len + 12; + ssl->in_msglen = msg_len + 12; + memcpy( ssl->in_msg, hs_buf->data, ssl->in_hslen ); + + ret = 0; + goto exit; + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message %u not or only partially bufffered", + hs->in_msg_seq ) ); + } + + ret = -1; + +exit: + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_message" ) ); + return( ret ); +} + +static int ssl_buffer_make_space( mbedtls_ssl_context *ssl, + size_t desired ) +{ + int offset; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Attempt to free buffered messages to have %u bytes available", + (unsigned) desired ) ); + + /* Get rid of future records epoch first, if such exist. */ + ssl_free_buffered_record( ssl ); + + /* Check if we have enough space available now. */ + if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing future epoch record" ) ); + return( 0 ); + } + + /* We don't have enough space to buffer the next expected handshake + * message. Remove buffers used for future messages to gain space, + * starting with the most distant one. */ + for( offset = MBEDTLS_SSL_MAX_BUFFERED_HS - 1; + offset >= 0; offset-- ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Free buffering slot %d to make space for reassembly of next handshake message", + offset ) ); + + ssl_buffering_free_slot( ssl, (uint8_t) offset ); + + /* Check if we have enough space available now. */ + if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing buffered HS messages" ) ); + return( 0 ); + } + } + + return( -1 ); +} + +static int ssl_buffer_message( mbedtls_ssl_context *ssl ) +{ + int ret = 0; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + if( hs == NULL ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_buffer_message" ) ); + + switch( ssl->in_msgtype ) + { + case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC: + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Remember CCS message" ) ); + + hs->buffering.seen_ccs = 1; + break; + + case MBEDTLS_SSL_MSG_HANDSHAKE: + { + unsigned recv_msg_seq_offset; + unsigned recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; + mbedtls_ssl_hs_buffer *hs_buf; + size_t msg_len = ssl->in_hslen - 12; + + /* We should never receive an old handshake + * message - double-check nonetheless. */ + if( recv_msg_seq < ssl->handshake->in_msg_seq ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + recv_msg_seq_offset = recv_msg_seq - ssl->handshake->in_msg_seq; + if( recv_msg_seq_offset >= MBEDTLS_SSL_MAX_BUFFERED_HS ) + { + /* Silently ignore -- message too far in the future */ + MBEDTLS_SSL_DEBUG_MSG( 2, + ( "Ignore future HS message with sequence number %u, " + "buffering window %u - %u", + recv_msg_seq, ssl->handshake->in_msg_seq, + ssl->handshake->in_msg_seq + MBEDTLS_SSL_MAX_BUFFERED_HS - 1 ) ); + + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering HS message with sequence number %u, offset %u ", + recv_msg_seq, recv_msg_seq_offset ) ); + + hs_buf = &hs->buffering.hs[ recv_msg_seq_offset ]; + + /* Check if the buffering for this seq nr has already commenced. */ + if( !hs_buf->is_valid ) + { + size_t reassembly_buf_sz; + + hs_buf->is_fragmented = + ( ssl_hs_is_proper_fragment( ssl ) == 1 ); + + /* We copy the message back into the input buffer + * after reassembly, so check that it's not too large. + * This is an implementation-specific limitation + * and not one from the standard, hence it is not + * checked in ssl_check_hs_header(). */ + if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + /* Ignore message */ + goto exit; + } + + /* Check if we have enough space to buffer the message. */ + if( hs->buffering.total_bytes_buffered > + MBEDTLS_SSL_DTLS_MAX_BUFFERING ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + reassembly_buf_sz = ssl_get_reassembly_buffer_size( msg_len, + hs_buf->is_fragmented ); + + if( reassembly_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + if( recv_msg_seq_offset > 0 ) + { + /* If we can't buffer a future message because + * of space limitations -- ignore. */ + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n", + (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING, + (unsigned) hs->buffering.total_bytes_buffered ) ); + goto exit; + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- attempt to make space by freeing buffered future messages\n", + (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING, + (unsigned) hs->buffering.total_bytes_buffered ) ); + } + + if( ssl_buffer_make_space( ssl, reassembly_buf_sz ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reassembly of next message of size %u (%u with bitmap) would exceed the compile-time limit %u (already %u bytes buffered) -- fail\n", + (unsigned) msg_len, + (unsigned) reassembly_buf_sz, + MBEDTLS_SSL_DTLS_MAX_BUFFERING, + (unsigned) hs->buffering.total_bytes_buffered ) ); + ret = MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL; + goto exit; + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d", + msg_len ) ); + + hs_buf->data = mbedtls_calloc( 1, reassembly_buf_sz ); + if( hs_buf->data == NULL ) + { + ret = MBEDTLS_ERR_SSL_ALLOC_FAILED; + goto exit; + } + hs_buf->data_len = reassembly_buf_sz; + + /* Prepare final header: copy msg_type, length and message_seq, + * then add standardised fragment_offset and fragment_length */ + memcpy( hs_buf->data, ssl->in_msg, 6 ); + memset( hs_buf->data + 6, 0, 3 ); + memcpy( hs_buf->data + 9, hs_buf->data + 1, 3 ); + + hs_buf->is_valid = 1; + + hs->buffering.total_bytes_buffered += reassembly_buf_sz; + } + else + { + /* Make sure msg_type and length are consistent */ + if( memcmp( hs_buf->data, ssl->in_msg, 4 ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Fragment header mismatch - ignore" ) ); + /* Ignore */ + goto exit; + } + } + + if( !hs_buf->is_complete ) + { + size_t frag_len, frag_off; + unsigned char * const msg = hs_buf->data + 12; + + /* + * Check and copy current fragment + */ + + /* Validation of header fields already done in + * mbedtls_ssl_prepare_handshake_record(). */ + frag_off = ssl_get_hs_frag_off( ssl ); + frag_len = ssl_get_hs_frag_len( ssl ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d", + frag_off, frag_len ) ); + memcpy( msg + frag_off, ssl->in_msg + 12, frag_len ); + + if( hs_buf->is_fragmented ) + { + unsigned char * const bitmask = msg + msg_len; + ssl_bitmask_set( bitmask, frag_off, frag_len ); + hs_buf->is_complete = ( ssl_bitmask_check( bitmask, + msg_len ) == 0 ); + } + else + { + hs_buf->is_complete = 1; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "message %scomplete", + hs_buf->is_complete ? "" : "not yet " ) ); + } + + break; + } + + default: + /* We don't buffer other types of messages. */ + break; + } + +exit: + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_buffer_message" ) ); + return( ret ); +} +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +static int ssl_consume_current_message( mbedtls_ssl_context *ssl ) +{ /* - * Step A - * * Consume last content-layer message and potentially * update in_msglen which keeps track of the contents' * consumption state. @@ -4464,20 +4806,161 @@ int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl ) ssl->in_msglen = 0; } - /* - * Step B - * - * Fetch and decode new record if current one is fully consumed. - * - */ + return( 0 ); +} +static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ) +{ if( ssl->in_msglen > 0 ) + return( 1 ); + + return( 0 ); +} + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + if( hs == NULL ) + return; + + if( hs->buffering.future_record.data != NULL ) { - /* There's something left to be processed in the current record. */ + hs->buffering.total_bytes_buffered -= + hs->buffering.future_record.len; + + mbedtls_free( hs->buffering.future_record.data ); + hs->buffering.future_record.data = NULL; + } +} + +static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + unsigned char * rec; + size_t rec_len; + unsigned rec_epoch; + + if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + return( 0 ); + + if( hs == NULL ) + return( 0 ); + + rec = hs->buffering.future_record.data; + rec_len = hs->buffering.future_record.len; + rec_epoch = hs->buffering.future_record.epoch; + + if( rec == NULL ) + return( 0 ); + + /* Only consider loading future records if the + * input buffer is empty. */ + if( ssl_next_record_is_in_datagram( ssl ) == 1 ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_record" ) ); + + if( rec_epoch != ssl->in_epoch ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffered record not from current epoch." ) ); + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Found buffered record from current epoch - load" ) ); + + /* Double-check that the record is not too large */ + if( rec_len > MBEDTLS_SSL_IN_BUFFER_LEN - + (size_t)( ssl->in_hdr - ssl->in_buf ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + memcpy( ssl->in_hdr, rec, rec_len ); + ssl->in_left = rec_len; + ssl->next_record_offset = 0; + + ssl_free_buffered_record( ssl ); + +exit: + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_record" ) ); + return( 0 ); +} + +static int ssl_buffer_future_record( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + size_t const rec_hdr_len = 13; + size_t const total_buf_sz = rec_hdr_len + ssl->in_msglen; + + /* Don't buffer future records outside handshakes. */ + if( hs == NULL ) + return( 0 ); + + /* Only buffer handshake records (we are only interested + * in Finished messages). */ + if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ) + return( 0 ); + + /* Don't buffer more than one future epoch record. */ + if( hs->buffering.future_record.data != NULL ) + return( 0 ); + + /* Don't buffer record if there's not enough buffering space remaining. */ + if( total_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future epoch record of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n", + (unsigned) total_buf_sz, MBEDTLS_SSL_DTLS_MAX_BUFFERING, + (unsigned) hs->buffering.total_bytes_buffered ) ); return( 0 ); } - /* Current record either fully processed or to be discarded. */ + /* Buffer record */ + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffer record from epoch %u", + ssl->in_epoch + 1 ) ); + MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered record", ssl->in_hdr, + rec_hdr_len + ssl->in_msglen ); + + /* ssl_parse_record_header() only considers records + * of the next epoch as candidates for buffering. */ + hs->buffering.future_record.epoch = ssl->in_epoch + 1; + hs->buffering.future_record.len = total_buf_sz; + + hs->buffering.future_record.data = + mbedtls_calloc( 1, hs->buffering.future_record.len ); + if( hs->buffering.future_record.data == NULL ) + { + /* If we run out of RAM trying to buffer a + * record from the next epoch, just ignore. */ + return( 0 ); + } + + memcpy( hs->buffering.future_record.data, ssl->in_hdr, total_buf_sz ); + + hs->buffering.total_bytes_buffered += total_buf_sz; + return( 0 ); +} + +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +static int ssl_get_next_record( mbedtls_ssl_context *ssl ) +{ + int ret; + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + /* We might have buffered a future record; if so, + * and if the epoch matches now, load it. + * On success, this call will set ssl->in_left to + * the length of the buffered record, so that + * the calls to ssl_fetch_input() below will + * essentially be no-ops. */ + ret = ssl_load_buffered_record( ssl ); + if( ret != 0 ) + return( ret ); +#endif /* MBEDTLS_SSL_PROTO_DTLS */ if( ( ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_hdr_len( ssl ) ) ) != 0 ) { @@ -4491,6 +4974,16 @@ int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl ) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ret != MBEDTLS_ERR_SSL_CLIENT_RECONNECT ) { + if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) + { + ret = ssl_buffer_future_record( ssl ); + if( ret != 0 ) + return( ret ); + + /* Fall through to handling of unexpected records */ + ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD; + } + if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ) { /* Skip unexpected record (but not whole datagram) */ @@ -4622,6 +5115,39 @@ int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl ) } } + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) + { + if( ssl->in_msglen != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, len: %d", + ssl->in_msglen ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + if( ssl->in_msg[0] != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, content: %02x", + ssl->in_msg[0] ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC && + ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) + { + if( ssl->handshake == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping ChangeCipherSpec outside handshake" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "received out-of-order ChangeCipherSpec - remember" ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } +#endif + } + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT ) { if( ssl->in_msglen != 2 ) @@ -4947,7 +5473,7 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl ) } #endif - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { /* mbedtls_ssl_read_record may have sent an alert already. We let it decide whether to alert. */ @@ -5322,7 +5848,7 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl ) MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) ); - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -5336,13 +5862,8 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl ) return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); } - if( ssl->in_msglen != 1 || ssl->in_msg[0] != 1 ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) ); - mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, - MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR ); - return( MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC ); - } + /* CCS records are only accepted if they have length 1 and content '1', + * so we don't need to check this here. */ /* * Switch to our negotiated transform and session parameters for inbound @@ -5951,7 +6472,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl ) ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 ); - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); return( ret ); @@ -7235,7 +7756,7 @@ int mbedtls_ssl_check_pending( const mbedtls_ssl_context *ssl ) /* * In all other cases, the rest of the message can be dropped. - * As in ssl_read_record_layer, this needs to be adapted if + * As in ssl_get_next_record, this needs to be adapted if * we implement support for multiple alerts in single records. */ @@ -7743,7 +8264,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len ) ssl_set_timer( ssl, ssl->conf->read_timeout ); } - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) return( 0 ); @@ -7758,7 +8279,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len ) /* * OpenSSL sends empty messages to randomize the IV */ - if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) { if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) return( 0 ); @@ -8192,6 +8713,41 @@ static void ssl_key_cert_free( mbedtls_ssl_key_cert *key_cert ) } #endif /* MBEDTLS_X509_CRT_PARSE_C */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +static void ssl_buffering_free( mbedtls_ssl_context *ssl ) +{ + unsigned offset; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + if( hs == NULL ) + return; + + ssl_free_buffered_record( ssl ); + + for( offset = 0; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) + ssl_buffering_free_slot( ssl, offset ); +} + +static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, + uint8_t slot ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + mbedtls_ssl_hs_buffer * const hs_buf = &hs->buffering.hs[slot]; + + if( slot >= MBEDTLS_SSL_MAX_BUFFERED_HS ) + return; + + if( hs_buf->is_valid == 1 ) + { + hs->buffering.total_bytes_buffered -= hs_buf->data_len; + mbedtls_free( hs_buf->data ); + memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); + } +} + +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + void mbedtls_ssl_handshake_free( mbedtls_ssl_context *ssl ) { mbedtls_ssl_handshake_params *handshake = ssl->handshake; @@ -8271,8 +8827,8 @@ void mbedtls_ssl_handshake_free( mbedtls_ssl_context *ssl ) #if defined(MBEDTLS_SSL_PROTO_DTLS) mbedtls_free( handshake->verify_cookie ); - mbedtls_free( handshake->hs_msg ); ssl_flight_free( handshake->flight ); + ssl_buffering_free( ssl ); #endif mbedtls_platform_zeroize( handshake, diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c index 55e0f249ce..41739d057f 100644 --- a/programs/test/udp_proxy.c +++ b/programs/test/udp_proxy.c @@ -40,6 +40,8 @@ #define mbedtls_time time #define mbedtls_time_t time_t #define mbedtls_printf printf +#define mbedtls_calloc calloc +#define mbedtls_free free #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE #endif /* MBEDTLS_PLATFORM_C */ @@ -106,6 +108,21 @@ int main( void ) " delay=%%d default: 0 (no delayed packets)\n" \ " delay about 1:N packets randomly\n" \ " delay_ccs=0/1 default: 0 (don't delay ChangeCipherSpec)\n" \ + " delay_cli=%%s Handshake message from client that should be\n"\ + " delayed. Possible values are 'ClientHello',\n" \ + " 'Certificate', 'CertificateVerify', and\n" \ + " 'ClientKeyExchange'.\n" \ + " May be used multiple times, even for the same\n"\ + " message, in which case the respective message\n"\ + " gets delayed multiple times.\n" \ + " delay_srv=%%s Handshake message from server that should be\n"\ + " delayed. Possible values are 'HelloRequest',\n"\ + " 'ServerHello', 'ServerHelloDone', 'Certificate'\n"\ + " 'ServerKeyExchange', 'NewSessionTicket',\n"\ + " 'HelloVerifyRequest' and ''CertificateRequest'.\n"\ + " May be used multiple times, even for the same\n"\ + " message, in which case the respective message\n"\ + " gets delayed multiple times.\n" \ " drop=%%d default: 0 (no dropped packets)\n" \ " drop about 1:N packets randomly\n" \ " mtu=%%d default: 0 (unlimited)\n" \ @@ -121,6 +138,9 @@ int main( void ) /* * global options */ + +#define MAX_DELAYED_HS 10 + static struct options { const char *server_addr; /* address to forward packets to */ @@ -131,6 +151,12 @@ static struct options int duplicate; /* duplicate 1 in N packets (none if 0) */ int delay; /* delay 1 packet in N (none if 0) */ int delay_ccs; /* delay ChangeCipherSpec */ + char* delay_cli[MAX_DELAYED_HS]; /* handshake types of messages from + * client that should be delayed. */ + uint8_t delay_cli_cnt; /* Number of entries in delay_cli. */ + char* delay_srv[MAX_DELAYED_HS]; /* handshake types of messages from + * server that should be delayed. */ + uint8_t delay_srv_cnt; /* Number of entries in delay_srv. */ int drop; /* drop 1 packet in N (none if 0) */ int mtu; /* drop packets larger than this */ int bad_ad; /* inject corrupted ApplicationData record */ @@ -164,6 +190,11 @@ static void get_options( int argc, char *argv[] ) opt.pack = DFL_PACK; /* Other members default to 0 */ + opt.delay_cli_cnt = 0; + opt.delay_srv_cnt = 0; + memset( opt.delay_cli, 0, sizeof( opt.delay_cli ) ); + memset( opt.delay_srv, 0, sizeof( opt.delay_srv ) ); + for( i = 1; i < argc; i++ ) { p = argv[i]; @@ -197,6 +228,43 @@ static void get_options( int argc, char *argv[] ) if( opt.delay_ccs < 0 || opt.delay_ccs > 1 ) exit_usage( p, q ); } + else if( strcmp( p, "delay_cli" ) == 0 || + strcmp( p, "delay_srv" ) == 0 ) + { + uint8_t *delay_cnt; + char **delay_list; + size_t len; + char *buf; + + if( strcmp( p, "delay_cli" ) == 0 ) + { + delay_cnt = &opt.delay_cli_cnt; + delay_list = opt.delay_cli; + } + else + { + delay_cnt = &opt.delay_srv_cnt; + delay_list = opt.delay_srv; + } + + if( *delay_cnt == MAX_DELAYED_HS ) + { + mbedtls_printf( " too many uses of %s: only %d allowed\n", + p, MAX_DELAYED_HS ); + exit_usage( p, NULL ); + } + + len = strlen( q ); + buf = mbedtls_calloc( 1, len + 1 ); + if( buf == NULL ) + { + mbedtls_printf( " Allocation failure\n" ); + exit( 1 ); + } + memcpy( buf, q, len + 1 ); + + delay_list[ (*delay_cnt)++ ] = buf; + } else if( strcmp( p, "drop" ) == 0 ) { opt.drop = atoi( q ); @@ -488,11 +556,37 @@ int send_packet( const packet *p, const char *why ) return( 0 ); } -static packet prev; +#define MAX_DELAYED_MSG 5 +static size_t prev_len; +static packet prev[MAX_DELAYED_MSG]; void clear_pending( void ) { - memset( &prev, 0, sizeof( packet ) ); + memset( &prev, 0, sizeof( prev ) ); + prev_len = 0; +} + +void delay_packet( packet *delay ) +{ + if( prev_len == MAX_DELAYED_MSG ) + return; + + memcpy( &prev[prev_len++], delay, sizeof( packet ) ); +} + +int send_delayed() +{ + uint8_t offset; + int ret; + for( offset = 0; offset < prev_len; offset++ ) + { + ret = send_packet( &prev[offset], "delayed" ); + if( ret != 0 ) + return( ret ); + } + + clear_pending(); + return( 0 ); } /* @@ -540,6 +634,10 @@ int handle_message( const char *way, packet cur; size_t id; + uint8_t delay_idx; + char ** delay_list; + uint8_t delay_list_len; + /* receive packet */ if( ( ret = mbedtls_net_recv( src, cur.buf, sizeof( cur.buf ) ) ) <= 0 ) { @@ -555,6 +653,37 @@ int handle_message( const char *way, id = cur.len % sizeof( dropped ); + if( strcmp( way, "S <- C" ) == 0 ) + { + delay_list = opt.delay_cli; + delay_list_len = opt.delay_cli_cnt; + } + else + { + delay_list = opt.delay_srv; + delay_list_len = opt.delay_srv_cnt; + } + + /* Check if message type is in the list of messages + * that should be delayed */ + for( delay_idx = 0; delay_idx < delay_list_len; delay_idx++ ) + { + if( delay_list[ delay_idx ] == NULL ) + continue; + + if( strcmp( delay_list[ delay_idx ], cur.type ) == 0 ) + { + /* Delay message */ + delay_packet( &cur ); + + /* Remove entry from list */ + mbedtls_free( delay_list[delay_idx] ); + delay_list[delay_idx] = NULL; + + return( 0 ); + } + } + /* do we want to drop, delay, or forward it? */ if( ( opt.mtu != 0 && cur.len > (unsigned) opt.mtu ) || @@ -574,12 +703,11 @@ int handle_message( const char *way, strcmp( cur.type, "ApplicationData" ) != 0 && ! ( opt.protect_hvr && strcmp( cur.type, "HelloVerifyRequest" ) == 0 ) && - prev.dst == NULL && cur.len != (size_t) opt.protect_len && dropped[id] < DROP_MAX && rand() % opt.delay == 0 ) ) { - memcpy( &prev, &cur, sizeof( packet ) ); + delay_packet( &cur ); } else { @@ -587,14 +715,10 @@ int handle_message( const char *way, if( ( ret = send_packet( &cur, "forwarded" ) ) != 0 ) return( ret ); - /* send previously delayed message if any */ - if( prev.dst != NULL ) - { - ret = send_packet( &prev, "delayed" ); - memset( &prev, 0, sizeof( packet ) ); - if( ret != 0 ) - return( ret ); - } + /* send previously delayed messages if any */ + ret = send_delayed(); + if( ret != 0 ) + return( ret ); } return( 0 ); @@ -604,6 +728,7 @@ int main( int argc, char *argv[] ) { int ret = 1; int exit_code = MBEDTLS_EXIT_FAILURE; + uint8_t delay_idx; mbedtls_net_context listen_fd, client_fd, server_fd; @@ -798,6 +923,12 @@ exit: } #endif + for( delay_idx = 0; delay_idx < MAX_DELAYED_HS; delay_idx++ ) + { + mbedtls_free( opt.delay_cli + delay_idx ); + mbedtls_free( opt.delay_srv + delay_idx ); + } + mbedtls_net_free( &client_fd ); mbedtls_net_free( &server_fd ); mbedtls_net_free( &listen_fd ); diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh index ca9c93ef2d..1faa5d561b 100755 --- a/tests/scripts/all.sh +++ b/tests/scripts/all.sh @@ -558,6 +558,26 @@ make msg "test: small SSL_IN_CONTENT_LEN - ssl-opt.sh MFL tests" if_build_succeeded tests/ssl-opt.sh -f "Max fragment" +msg "build: small MBEDTLS_SSL_DTLS_MAX_BUFFERING #0" +cleanup +cp "$CONFIG_H" "$CONFIG_BAK" +scripts/config.pl set MBEDTLS_SSL_DTLS_MAX_BUFFERING 1000 +CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan . +make + +msg "test: small MBEDTLS_SSL_DTLS_MAX_BUFFERING #0 - ssl-opt.sh specific reordering test" +if_build_succeeded tests/ssl-opt.sh -f "DTLS reordering: Buffer out-of-order hs msg before reassembling next, free buffered msg" + +msg "build: small MBEDTLS_SSL_DTLS_MAX_BUFFERING #1" +cleanup +cp "$CONFIG_H" "$CONFIG_BAK" +scripts/config.pl set MBEDTLS_SSL_DTLS_MAX_BUFFERING 240 +CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan . +make + +msg "test: small MBEDTLS_SSL_DTLS_MAX_BUFFERING #1 - ssl-opt.sh specific reordering test" +if_build_succeeded tests/ssl-opt.sh -f "DTLS reordering: Buffer encrypted Finished message, drop for fragmented NewSessionTicket" + msg "build: cmake, full config, clang" # ~ 50s cleanup cp "$CONFIG_H" "$CONFIG_BAK" diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh index 53c88bec87..227d04280b 100755 --- a/tests/ssl-opt.sh +++ b/tests/ssl-opt.sh @@ -142,6 +142,14 @@ get_options() { done } +# Skip next test; use this macro to skip tests which are legitimate +# in theory and expected to be re-introduced at some point, but +# aren't expected to succeed at the moment due to problems outside +# our control (such as bugs in other TLS implementations). +skip_next_test() { + SKIP_NEXT="YES" +} + # skip next test if the flag is not enabled in config.h requires_config_enabled() { if grep "^#define $1" $CONFIG_H > /dev/null; then :; else @@ -156,6 +164,27 @@ requires_config_disabled() { fi } +get_config_value_or_default() { + NAME="$1" + DEF_VAL=$( grep ".*#define.*${NAME}" ../include/mbedtls/config.h | + sed 's/^.*\s\([0-9]*\)$/\1/' ) + ../scripts/config.pl get $NAME || echo "$DEF_VAL" +} + +requires_config_value_at_least() { + VAL=$( get_config_value_or_default "$1" ) + if [ "$VAL" -lt "$2" ]; then + SKIP_NEXT="YES" + fi +} + +requires_config_value_at_most() { + VAL=$( get_config_value_or_default "$1" ) + if [ "$VAL" -gt "$2" ]; then + SKIP_NEXT="YES" + fi +} + # skip next test if OpenSSL doesn't support FALLBACK_SCSV requires_openssl_with_fallback_scsv() { if [ -z "${OPENSSL_HAS_FBSCSV:-}" ]; then @@ -5297,9 +5326,8 @@ run_test "DTLS fragmenting: proxy MTU, simple handshake, nbio" \ -c "found fragmented DTLS handshake message" \ -C "error" -# This ensures things still work after session_reset(), -# for example it would have caught #1941. -# It also exercises the "resumed hanshake" flow. +# This ensures things still work after session_reset(). +# It also exercises the "resumed handshake" flow. # Since we don't support reading fragmented ClientHello yet, # up the MTU to 1450 (larger than ClientHello with session ticket, # but still smaller than client's Certificate to ensure fragmentation). @@ -5551,6 +5579,13 @@ run_test "DTLS fragmenting: gnutls server, DTLS 1.0" \ -c "fragmenting handshake message" \ -C "error" +# We use --insecure for the GnuTLS client because it expects +# the hostname / IP it connects to to be the name used in the +# certificate obtained from the server. Here, however, it +# connects to 127.0.0.1 while our test certificates use 'localhost' +# as the server name in the certificate. This will make the +# certifiate validation fail, but passing --insecure makes +# GnuTLS continue the connection nonetheless. requires_config_enabled MBEDTLS_SSL_PROTO_DTLS requires_config_enabled MBEDTLS_RSA_C requires_config_enabled MBEDTLS_ECDSA_C @@ -5565,6 +5600,7 @@ run_test "DTLS fragmenting: gnutls client, DTLS 1.2" \ 0 \ -s "fragmenting handshake message" +# See previous test for the reason to use --insecure requires_config_enabled MBEDTLS_SSL_PROTO_DTLS requires_config_enabled MBEDTLS_RSA_C requires_config_enabled MBEDTLS_ECDSA_C @@ -5676,38 +5712,39 @@ run_test "DTLS fragmenting: 3d, gnutls server, DTLS 1.0" \ ## https://gitlab.com/gnutls/gnutls/issues/543 ## We can re-enable them when a fixed version fo GnuTLS is available ## and installed in our CI system. -## -## requires_gnutls -## requires_config_enabled MBEDTLS_SSL_PROTO_DTLS -## requires_config_enabled MBEDTLS_RSA_C -## requires_config_enabled MBEDTLS_ECDSA_C -## requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2 -## client_needs_more_time 4 -## run_test "DTLS fragmenting: 3d, gnutls client, DTLS 1.2" \ -## -p "$P_PXY drop=8 delay=8 duplicate=8" \ -## "$P_SRV dtls=1 debug_level=2 \ -## crt_file=data_files/server7_int-ca.crt \ -## key_file=data_files/server7.key \ -## hs_timeout=250-60000 mtu=512 force_version=dtls1_2" \ -## "$G_CLI -u --insecure 127.0.0.1" \ -## 0 \ -## -s "fragmenting handshake message" -## -## requires_gnutls -## requires_config_enabled MBEDTLS_SSL_PROTO_DTLS -## requires_config_enabled MBEDTLS_RSA_C -## requires_config_enabled MBEDTLS_ECDSA_C -## requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_1 -## client_needs_more_time 4 -## run_test "DTLS fragmenting: 3d, gnutls client, DTLS 1.0" \ -## -p "$P_PXY drop=8 delay=8 duplicate=8" \ -## "$P_SRV dtls=1 debug_level=2 \ -## crt_file=data_files/server7_int-ca.crt \ -## key_file=data_files/server7.key \ -## hs_timeout=250-60000 mtu=512 force_version=dtls1" \ -## "$G_CLI -u --insecure 127.0.0.1" \ -## 0 \ -## -s "fragmenting handshake message" +skip_next_test +requires_gnutls +requires_config_enabled MBEDTLS_SSL_PROTO_DTLS +requires_config_enabled MBEDTLS_RSA_C +requires_config_enabled MBEDTLS_ECDSA_C +requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2 +client_needs_more_time 4 +run_test "DTLS fragmenting: 3d, gnutls client, DTLS 1.2" \ + -p "$P_PXY drop=8 delay=8 duplicate=8" \ + "$P_SRV dtls=1 debug_level=2 \ + crt_file=data_files/server7_int-ca.crt \ + key_file=data_files/server7.key \ + hs_timeout=250-60000 mtu=512 force_version=dtls1_2" \ + "$G_CLI -u --insecure 127.0.0.1" \ + 0 \ + -s "fragmenting handshake message" + +skip_next_test +requires_gnutls +requires_config_enabled MBEDTLS_SSL_PROTO_DTLS +requires_config_enabled MBEDTLS_RSA_C +requires_config_enabled MBEDTLS_ECDSA_C +requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_1 +client_needs_more_time 4 +run_test "DTLS fragmenting: 3d, gnutls client, DTLS 1.0" \ + -p "$P_PXY drop=8 delay=8 duplicate=8" \ + "$P_SRV dtls=1 debug_level=2 \ + crt_file=data_files/server7_int-ca.crt \ + key_file=data_files/server7.key \ + hs_timeout=250-60000 mtu=512 force_version=dtls1" \ + "$G_CLI -u --insecure 127.0.0.1" \ + 0 \ + -s "fragmenting handshake message" ## Interop test with OpenSSL might triger a bug in recent versions (that ## probably won't be fixed before 1.1.1X), so we use an old version that @@ -5716,22 +5753,22 @@ run_test "DTLS fragmenting: 3d, gnutls server, DTLS 1.0" \ ## Bug report: https://github.com/openssl/openssl/issues/6902 ## They should be re-enabled (and the DTLS 1.0 switched back to a non-legacy ## version of OpenSSL once a fixed version of OpenSSL is available) -## -## requires_config_enabled MBEDTLS_SSL_PROTO_DTLS -## requires_config_enabled MBEDTLS_RSA_C -## requires_config_enabled MBEDTLS_ECDSA_C -## requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2 -## client_needs_more_time 4 -## run_test "DTLS fragmenting: 3d, openssl server, DTLS 1.2" \ -## -p "$P_PXY drop=8 delay=8 duplicate=8" \ -## "$O_SRV -dtls1_2 -verify 10" \ -## "$P_CLI dtls=1 debug_level=2 \ -## crt_file=data_files/server8_int-ca2.crt \ -## key_file=data_files/server8.key \ -## hs_timeout=250-60000 mtu=512 force_version=dtls1_2" \ -## 0 \ -## -c "fragmenting handshake message" \ -## -C "error" +skip_next_test +requires_config_enabled MBEDTLS_SSL_PROTO_DTLS +requires_config_enabled MBEDTLS_RSA_C +requires_config_enabled MBEDTLS_ECDSA_C +requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2 +client_needs_more_time 4 +run_test "DTLS fragmenting: 3d, openssl server, DTLS 1.2" \ + -p "$P_PXY drop=8 delay=8 duplicate=8" \ + "$O_SRV -dtls1_2 -verify 10" \ + "$P_CLI dtls=1 debug_level=2 \ + crt_file=data_files/server8_int-ca2.crt \ + key_file=data_files/server8.key \ + hs_timeout=250-60000 mtu=512 force_version=dtls1_2" \ + 0 \ + -c "fragmenting handshake message" \ + -C "error" requires_openssl_legacy requires_config_enabled MBEDTLS_SSL_PROTO_DTLS @@ -5904,6 +5941,158 @@ run_test "DTLS proxy: delay ChangeCipherSpec" \ -s "Extra-header:" \ -c "HTTP/1.0 200 OK" +# Tests for reordering support with DTLS + +run_test "DTLS reordering: Buffer out-of-order handshake message on client" \ + -p "$P_PXY delay_srv=ServerHello" \ + "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -c "Buffering HS message" \ + -c "Next handshake message has been buffered - load"\ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load"\ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +run_test "DTLS reordering: Buffer out-of-order handshake message fragment on client" \ + -p "$P_PXY delay_srv=ServerHello" \ + "$P_SRV mtu=512 dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -c "Buffering HS message" \ + -c "found fragmented DTLS handshake message"\ + -c "Next handshake message 1 not or only partially bufffered" \ + -c "Next handshake message has been buffered - load"\ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load"\ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +# The client buffers the ServerKeyExchange before receiving the fragmented +# Certificate message; at the time of writing, together these are aroudn 1200b +# in size, so that the bound below ensures that the certificate can be reassembled +# while keeping the ServerKeyExchange. +requires_config_value_at_least "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 1300 +run_test "DTLS reordering: Buffer out-of-order hs msg before reassembling next" \ + -p "$P_PXY delay_srv=Certificate delay_srv=Certificate" \ + "$P_SRV mtu=512 dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -c "Buffering HS message" \ + -c "Next handshake message has been buffered - load"\ + -C "attempt to make space by freeing buffered messages" \ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load"\ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +# The size constraints ensure that the delayed certificate message can't +# be reassembled while keeping the ServerKeyExchange message, but it can +# when dropping it first. +requires_config_value_at_least "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 900 +requires_config_value_at_most "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 1299 +run_test "DTLS reordering: Buffer out-of-order hs msg before reassembling next, free buffered msg" \ + -p "$P_PXY delay_srv=Certificate delay_srv=Certificate" \ + "$P_SRV mtu=512 dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -c "Buffering HS message" \ + -c "attempt to make space by freeing buffered future messages" \ + -c "Enough space available after freeing buffered HS messages" \ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load"\ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +run_test "DTLS reordering: Buffer out-of-order handshake message on server" \ + -p "$P_PXY delay_cli=Certificate" \ + "$P_SRV dgram_packing=0 auth_mode=required cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -C "Buffering HS message" \ + -C "Next handshake message has been buffered - load"\ + -s "Buffering HS message" \ + -s "Next handshake message has been buffered - load" \ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +run_test "DTLS reordering: Buffer out-of-order CCS message on client"\ + -p "$P_PXY delay_srv=NewSessionTicket" \ + "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -C "Buffering HS message" \ + -C "Next handshake message has been buffered - load"\ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load" \ + -c "Injecting buffered CCS message" \ + -c "Remember CCS message" \ + -S "Injecting buffered CCS message" \ + -S "Remember CCS message" + +run_test "DTLS reordering: Buffer out-of-order CCS message on server"\ + -p "$P_PXY delay_cli=ClientKeyExchange" \ + "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -C "Buffering HS message" \ + -C "Next handshake message has been buffered - load"\ + -S "Buffering HS message" \ + -S "Next handshake message has been buffered - load" \ + -C "Injecting buffered CCS message" \ + -C "Remember CCS message" \ + -s "Injecting buffered CCS message" \ + -s "Remember CCS message" + +run_test "DTLS reordering: Buffer encrypted Finished message" \ + -p "$P_PXY delay_ccs=1" \ + "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \ + 0 \ + -s "Buffer record from epoch 1" \ + -s "Found buffered record from current epoch - load" \ + -c "Buffer record from epoch 1" \ + -c "Found buffered record from current epoch - load" + +# In this test, both the fragmented NewSessionTicket and the ChangeCipherSpec +# from the server are delayed, so that the encrypted Finished message +# is received and buffered. When the fragmented NewSessionTicket comes +# in afterwards, the encrypted Finished message must be freed in order +# to make space for the NewSessionTicket to be reassembled. +# This works only in very particular circumstances: +# - MBEDTLS_SSL_DTLS_MAX_BUFFERING must be large enough to allow buffering +# of the NewSessionTicket, but small enough to also allow buffering of +# the encrypted Finished message. +# - The MTU setting on the server must be so small that the NewSessionTicket +# needs to be fragmented. +# - All messages sent by the server must be small enough to be either sent +# without fragmentation or be reassembled within the bounds of +# MBEDTLS_SSL_DTLS_MAX_BUFFERING. Achieve this by testing with a PSK-based +# handshake, omitting CRTs. +requires_config_value_at_least "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 240 +requires_config_value_at_most "MBEDTLS_SSL_DTLS_MAX_BUFFERING" 280 +run_test "DTLS reordering: Buffer encrypted Finished message, drop for fragmented NewSessionTicket" \ + -p "$P_PXY delay_srv=NewSessionTicket delay_srv=NewSessionTicket delay_ccs=1" \ + "$P_SRV mtu=190 dgram_packing=0 psk=abc123 psk_identity=foo cookies=0 dtls=1 debug_level=2" \ + "$P_CLI dgram_packing=0 dtls=1 debug_level=2 force_ciphersuite=TLS-PSK-WITH-AES-128-CCM-8 psk=abc123 psk_identity=foo" \ + 0 \ + -s "Buffer record from epoch 1" \ + -s "Found buffered record from current epoch - load" \ + -c "Buffer record from epoch 1" \ + -C "Found buffered record from current epoch - load" \ + -c "Enough space available after freeing future epoch record" + # Tests for "randomly unreliable connection": try a variety of flows and peers client_needs_more_time 2