diff options
Diffstat (limited to 'lib/ext/ec_point_formats.c')
-rw-r--r-- | lib/ext/ec_point_formats.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/lib/ext/ec_point_formats.c b/lib/ext/ec_point_formats.c new file mode 100644 index 0000000000..657eb6625d --- /dev/null +++ b/lib/ext/ec_point_formats.c @@ -0,0 +1,124 @@ +/* + * Copyright (C) 2011-2012 Free Software Foundation, Inc. + * Copyright (C) 2017 Red Hat, Inc. + * + * Author: Nikos Mavrogiannopoulos + * + * This file is part of GnuTLS. + * + * The GnuTLS is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/> + * + */ + +/* This file contains the code for the Elliptic Curve Point Formats extension. + */ + +#include "ext/ec_point_formats.h" +#include "str.h" +#include "state.h" +#include <gnutls/gnutls.h> + + +static int _gnutls_supported_ec_point_formats_recv_params(gnutls_session_t session, + const uint8_t * data, + size_t data_size); +static int _gnutls_supported_ec_point_formats_send_params(gnutls_session_t session, + gnutls_buffer_st * extdata); + + +const hello_ext_entry_st ext_mod_supported_ec_point_formats = { + .name = "Supported EC Point Formats", + .tls_id = 11, + .gid = GNUTLS_EXTENSION_SUPPORTED_EC_POINT_FORMATS, + .parse_type = GNUTLS_EXT_TLS, + .validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_DTLS | + GNUTLS_EXT_FLAG_CLIENT_HELLO | GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO, + .recv_func = _gnutls_supported_ec_point_formats_recv_params, + .send_func = _gnutls_supported_ec_point_formats_send_params, + .pack_func = NULL, + .unpack_func = NULL, + .deinit_func = NULL +}; + + +/* Receive point formats + */ +static int +_gnutls_supported_ec_point_formats_recv_params(gnutls_session_t session, + const uint8_t * data, + size_t _data_size) +{ + int len, i; + int uncompressed = 0; + int data_size = _data_size; + + if (session->security_parameters.entity == GNUTLS_CLIENT) { + if (data_size < 1) + return + gnutls_assert_val + (GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION); + + len = data[0]; + if (len < 1) + return + gnutls_assert_val + (GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION); + + DECR_LEN(data_size, len + 1); + + for (i = 1; i <= len; i++) + if (data[i] == 0) { /* uncompressed */ + uncompressed = 1; + break; + } + + if (uncompressed == 0) + return + gnutls_assert_val + (GNUTLS_E_UNKNOWN_PK_ALGORITHM); + } else { + /* only sanity check here. We only support uncompressed points + * and a client must support it thus nothing to check. + */ + if (_data_size < 1) + return + gnutls_assert_val + (GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION); + } + + return 0; +} + +/* returns data_size or a negative number on failure + */ +static int +_gnutls_supported_ec_point_formats_send_params(gnutls_session_t session, + gnutls_buffer_st * extdata) +{ + const uint8_t p[2] = { 0x01, 0x00 }; /* only support uncompressed point format */ + int ret; + + if (session->security_parameters.entity == GNUTLS_SERVER + && !_gnutls_session_is_ecc(session)) + return 0; + + if (session->internals.priorities->groups.size > 0) { + ret = _gnutls_buffer_append_data(extdata, p, 2); + if (ret < 0) + return gnutls_assert_val(ret); + + return 2; + } + return 0; +} |