/*

 * Copyright (C) 2015-2016 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/>

 *

 */

/* Functions that relate to the TLS handshake procedure.

 */

#include "gnutls_int.h"

#include "errors.h"

#include "debug.h"

#include "handshake.h"

#include <auth/cert.h>

#include "constate.h"

#include <record.h>

#include <state.h>

#include <ext/safe_renegotiation.h>

#include <auth/anon.h>		/* for gnutls_anon_server_credentials_t */

#include <auth/psk.h>		/* for gnutls_psk_server_credentials_t */

#ifdef ENABLE_SRP

# include <auth/srp_kx.h>

#endif

int _gnutls_check_id_for_change(gnutls_session_t session)

{

	int cred_type;

	/* This checks in PSK and SRP ciphersuites that the username remained the

	 * same on a rehandshake. */

	if (session->internals.flags & GNUTLS_ALLOW_ID_CHANGE)

		return 0;

	cred_type = gnutls_auth_get_type(session);

	if (cred_type == GNUTLS_CRD_PSK || cred_type == GNUTLS_CRD_SRP) {

		const char *username = NULL;

		int username_length;

		if (cred_type == GNUTLS_CRD_PSK) {

			psk_auth_info_t ai;

			ai = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);

			if (ai == NULL)

				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

			username = ai->username;

			username_length = ai->username_len;

#ifdef ENABLE_SRP

		} else {

			srp_server_auth_info_t ai = _gnutls_get_auth_info(session, GNUTLS_CRD_SRP);

			if (ai == NULL)

				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

			username = ai->username;

			username_length = strlen(ai->username);

#endif

		}

		if (username == NULL)

			return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

		if (session->internals.saved_username_size != -1) {

			if (session->internals.saved_username_size == username_length &&

			    strncmp(session->internals.saved_username, username, username_length) != 0) {

				_gnutls_debug_log("Session's PSK username changed during rehandshake; aborting!\n");

				return gnutls_assert_val(GNUTLS_E_SESSION_USER_ID_CHANGED);

			}

		} else {

			memcpy(session->internals.saved_username, username, username_length);

			session->internals.saved_username[username_length] = 0;

			session->internals.saved_username_size = username_length;

		}

	}

	return 0;

}

int _gnutls_check_if_cert_hash_is_same(gnutls_session_t session, gnutls_certificate_credentials_t cred)

{

	cert_auth_info_t ai;

	char tmp[32];

	int ret;

	if (session->internals.flags & GNUTLS_ALLOW_ID_CHANGE)

		return 0;

	ai = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);

	if (ai == NULL || ai->ncerts == 0)

		return 0;

	ret = gnutls_hash_fast(GNUTLS_DIG_SHA256, 

			       ai->raw_certificate_list[0].data,

			       ai->raw_certificate_list[0].size,

			       tmp);

	if (ret < 0)

		return gnutls_assert_val(ret);

	if (session->internals.cert_hash_set) {

		if (memcmp(tmp, session->internals.cert_hash, 32) != 0) {

			_gnutls_debug_log("Session certificate changed during rehandshake; aborting!\n");

			return gnutls_assert_val(GNUTLS_E_SESSION_USER_ID_CHANGED);

		}

	} else {

		memcpy(session->internals.cert_hash, tmp, 32);

		session->internals.cert_hash_set = 1;

	}

	return 0;

}