diff --git a/library/ssl_tls.c b/library/ssl_tls.c index 7e8476cc6..c6aac473c 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -3522,81 +3522,23 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl ) return( MBEDTLS_ERR_SSL_INVALID_RECORD ); } - /* Check length against bounds of the current transform and version */ - if( ssl->transform_in == NULL ) - { - if( ssl->in_msglen < 1 || - ssl->in_msglen > MBEDTLS_SSL_MAX_CONTENT_LEN ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } - } - else - { - if( ssl->in_msglen < ssl->transform_in->minlen ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } - -#if defined(MBEDTLS_SSL_PROTO_SSL3) - if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 && - ssl->in_msglen > ssl->transform_in->minlen + MBEDTLS_SSL_MAX_CONTENT_LEN ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } -#endif -#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ - defined(MBEDTLS_SSL_PROTO_TLS1_2) - /* - * TLS encrypted messages can have up to 256 bytes of padding - */ - if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 && - ssl->in_msglen > ssl->transform_in->minlen + - MBEDTLS_SSL_MAX_CONTENT_LEN + 256 ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); - return( MBEDTLS_ERR_SSL_INVALID_RECORD ); - } -#endif - } - /* - * DTLS-related tests done last, because most of them may result in - * silently dropping the record (but not the whole datagram), and we only - * want to consider that after ensuring that the "basic" fields (type, - * version, length) are sane. + * DTLS-related tests. + * Check epoch before checking length constraint because + * the latter varies with the epoch. E.g., if a ChangeCipherSpec + * message gets duplicated before the corresponding Finished message, + * the second ChangeCipherSpec should be discarded because it belongs + * to an old epoch, but not because its length is shorter than + * the minimum record length for packets using the new record transform. + * Note that these two kinds of failures are handled differently, + * as an unexpected record is silently skipped but an invalid + * record leads to the entire datagram being dropped. */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) { unsigned int rec_epoch = ( ssl->in_ctr[0] << 8 ) | ssl->in_ctr[1]; - /* 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 && - ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER -#if defined(MBEDTLS_SSL_RENEGOTIATION) - && ! ( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && - ssl->state == MBEDTLS_SSL_SERVER_HELLO ) -#endif - ) - { - MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ApplicationData" ) ); - return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); - } - /* Check epoch (and sequence number) with DTLS */ if( rec_epoch != ssl->in_epoch ) { @@ -3636,9 +3578,74 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl ) return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); } #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 && + ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER +#if defined(MBEDTLS_SSL_RENEGOTIATION) + && ! ( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && + ssl->state == MBEDTLS_SSL_SERVER_HELLO ) +#endif + ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ApplicationData" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } } #endif /* MBEDTLS_SSL_PROTO_DTLS */ + + /* Check length against bounds of the current transform and version */ + if( ssl->transform_in == NULL ) + { + if( ssl->in_msglen < 1 || + ssl->in_msglen > MBEDTLS_SSL_MAX_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + } + else + { + if( ssl->in_msglen < ssl->transform_in->minlen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 && + ssl->in_msglen > ssl->transform_in->minlen + MBEDTLS_SSL_MAX_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif +#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_2) + /* + * TLS encrypted messages can have up to 256 bytes of padding + */ + if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 && + ssl->in_msglen > ssl->transform_in->minlen + + MBEDTLS_SSL_MAX_CONTENT_LEN + 256 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif + } + return( 0 ); } diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh index fbb689a0b..57d5e6053 100755 --- a/tests/ssl-opt.sh +++ b/tests/ssl-opt.sh @@ -3702,8 +3702,8 @@ run_test "DTLS proxy: duplicate every packet" \ 0 \ -c "replayed record" \ -s "replayed record" \ - -c "discarding invalid record" \ - -s "discarding invalid record" \ + -c "record from another epoch" \ + -s "record from another epoch" \ -S "resend" \ -s "Extra-header:" \ -c "HTTP/1.0 200 OK" @@ -3715,8 +3715,8 @@ run_test "DTLS proxy: duplicate every packet, server anti-replay off" \ 0 \ -c "replayed record" \ -S "replayed record" \ - -c "discarding invalid record" \ - -s "discarding invalid record" \ + -c "record from another epoch" \ + -s "record from another epoch" \ -c "resend" \ -s "resend" \ -s "Extra-header:" \ @@ -3777,8 +3777,6 @@ run_test "DTLS proxy: delay ChangeCipherSpec" \ 0 \ -c "record from another epoch" \ -s "record from another epoch" \ - -c "discarding invalid record" \ - -s "discarding invalid record" \ -s "Extra-header:" \ -c "HTTP/1.0 200 OK"