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/*
* 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 <https://www.gnu.org/licenses/>
*
*/
/* This file contains the code for the Max Record Size TLS extension.
*/
#include "gnutls_int.h"
#include "errors.h"
#include "num.h"
#include "hello_ext_lib.h"
#include "ext/cookie.h"
static int cookie_recv_params(gnutls_session_t session, const uint8_t *data,
size_t data_size);
static int cookie_send_params(gnutls_session_t session,
gnutls_buffer_st *extdata);
const hello_ext_entry_st ext_mod_cookie = {
.name = "Cookie",
.tls_id = 44,
.gid = GNUTLS_EXTENSION_COOKIE,
.validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_CLIENT_HELLO |
GNUTLS_EXT_FLAG_HRR | GNUTLS_EXT_FLAG_IGNORE_CLIENT_REQUEST,
.client_parse_point =
GNUTLS_EXT_MANDATORY, /* force parsing prior to EXT_TLS extensions */
.server_parse_point =
GNUTLS_EXT_MANDATORY, /* force parsing prior to EXT_TLS extensions */
.recv_func = cookie_recv_params,
.send_func = cookie_send_params,
.pack_func = NULL,
.unpack_func = NULL,
.deinit_func = _gnutls_hello_ext_default_deinit,
.cannot_be_overriden = 0
};
/* Only client sends this extension. */
static int cookie_recv_params(gnutls_session_t session, const uint8_t *data,
size_t data_size)
{
size_t csize;
int ret;
gnutls_datum_t tmp;
if (session->security_parameters.entity == GNUTLS_SERVER) {
/* we don't support it */
return 0;
} else { /* client */
if (_gnutls_ext_get_msg(session) == GNUTLS_EXT_FLAG_HRR) {
DECR_LEN(data_size, 2);
csize = _gnutls_read_uint16(data);
data += 2;
DECR_LEN(data_size, csize);
if (data_size != 0)
return gnutls_assert_val(
GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
tmp.data = (void *)data;
tmp.size = csize;
ret = _gnutls_hello_ext_set_datum(
session, GNUTLS_EXTENSION_COOKIE, &tmp);
if (ret < 0)
return gnutls_assert_val(ret);
return 0;
}
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
}
return 0;
}
/* returns data_size or a negative number on failure
*/
static int cookie_send_params(gnutls_session_t session,
gnutls_buffer_st *extdata)
{
gnutls_datum_t tmp;
int ret;
/* this function sends the client extension data (dnsname) */
if (session->security_parameters.entity == GNUTLS_CLIENT) {
ret = _gnutls_hello_ext_get_datum(
session, GNUTLS_EXTENSION_COOKIE, &tmp);
if (ret < 0)
return 0;
ret = _gnutls_buffer_append_data_prefix(extdata, 16, tmp.data,
tmp.size);
if (ret < 0)
return gnutls_assert_val(ret);
return 0;
}
return 0;
}
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