/*

 * 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 Post-Handshake TLS 1.3 extension.

 */

#include "gnutls_int.h"

#include "errors.h"

#include "num.h"

#include <hello_ext.h>

#include <ext/post_handshake.h>

#include "auth/cert.h"

static int _gnutls_post_handshake_recv_params(gnutls_session_t session,

					  const uint8_t * data,

					  size_t data_size);

static int _gnutls_post_handshake_send_params(gnutls_session_t session,

					  gnutls_buffer_st * extdata);

const hello_ext_entry_st ext_mod_post_handshake = {

	.name = "Post Handshake Auth",

	.tls_id = 49,

	.gid = GNUTLS_EXTENSION_POST_HANDSHAKE,

	.client_parse_point = GNUTLS_EXT_TLS,

	.server_parse_point = GNUTLS_EXT_TLS,

	.validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_CLIENT_HELLO,

	.recv_func = _gnutls_post_handshake_recv_params,

	.send_func = _gnutls_post_handshake_send_params,

	.pack_func = NULL,

	.unpack_func = NULL,

	.deinit_func = NULL,

	.cannot_be_overriden = 1

};

static int

_gnutls_post_handshake_recv_params(gnutls_session_t session,

			       const uint8_t * data, size_t _data_size)

{

	const version_entry_st *vers;

	if (session->security_parameters.entity == GNUTLS_SERVER) {

		vers = get_version(session);

		if (unlikely(vers == NULL))

			return 0;

		if ((session->internals.flags & GNUTLS_POST_HANDSHAKE_AUTH) &&

		    vers->post_handshake_auth)

			session->security_parameters.post_handshake_auth = 1;

	}

	return 0;

}

/* returns data_size or a negative number on failure

 */

static int

_gnutls_post_handshake_send_params(gnutls_session_t session,

			       gnutls_buffer_st * extdata)

{

	gnutls_certificate_credentials_t cred;

	const version_entry_st *max;

	if (session->security_parameters.entity != GNUTLS_CLIENT ||

	    !(session->internals.flags & GNUTLS_POST_HANDSHAKE_AUTH)) {

		/* not sent on server side */

		return 0;

	}

	cred = (gnutls_certificate_credentials_t)

	    _gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE);

	if (cred == NULL)	/* no certificate authentication */

		return gnutls_assert_val(0);

	max = _gnutls_version_max(session);

	if (unlikely(max == NULL))

		return gnutls_assert_val(0);

	if (max->post_handshake_auth)

		return GNUTLS_E_INT_RET_0;

	else

		return 0;

}