diff --git a/library/ssl_cli.c b/library/ssl_cli.c index 9dbf4e6033..9050edb845 100644 --- a/library/ssl_cli.c +++ b/library/ssl_cli.c @@ -526,6 +526,23 @@ static int ssl_parse_renegotiation_info( ssl_context *ssl, return( 0 ); } +static int ssl_parse_max_fragment_length_ext( ssl_context *ssl, + unsigned char *buf, + size_t len ) +{ + /* + * server should use the extension only if we did, + * and if so the server's value should match ours (and len is always 1) + */ + if( ssl->mfl_code == SSL_MAX_FRAG_LEN_NONE || + len != 1 || + buf[0] != ssl->mfl_code ) + { + return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO ); + } + + return( 0 ); +} static int ssl_parse_server_hello( ssl_context *ssl ) { @@ -743,6 +760,17 @@ static int ssl_parse_server_hello( ssl_context *ssl ) break; + case TLS_EXT_MAX_FRAGMENT_LENGTH: + SSL_DEBUG_MSG( 3, ( "found max_fragment_length extension" ) ); + + if( ( ret = ssl_parse_max_fragment_length_ext( ssl, + ext + 4, ext_size ) ) != 0 ) + { + return( ret ); + } + + break; + default: SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)", ext_id ) );