Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle 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 General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * @package    core

 * @subpackage session

 * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}

 * @copyright  2008, 2009 Petr Skoda  {@link http://skodak.org}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

/**

 * Makes sure that $USER->sesskey exists, if $USER itself exists. It sets a new sesskey

 * if one does not already exist, but does not overwrite existing sesskeys. Returns the

 * sesskey string if $USER exists, or boolean false if not.

 *

 * @uses $USER

 * @return string

 */

function sesskey() {

    // note: do not use $USER because it may not be initialised yet

    if (empty($_SESSION['USER']->sesskey)) {

        if (!isset($_SESSION['USER'])) {

            // This should never happen,

            // do not mess with session and globals here,

            // let any checks fail instead!

            return false;

        }

        $_SESSION['USER']->sesskey = random_string(10);

    }

    return $_SESSION['USER']->sesskey;

}

/**

 * Check the sesskey and return true of false for whether it is valid.

 * (You might like to imagine this function is called sesskey_is_valid().)

 *

 * Every script that lets the user perform a significant action (that is,

 * changes data in the database) should check the sesskey before doing the action.

 * Depending on your code flow, you may want to use the {@link require_sesskey()}

 * helper function.

 *

 * @param string $sesskey The sesskey value to check (optional). Normally leave this blank

 *      and this function will do required_param('sesskey', ...).

 * @return bool whether the sesskey sent in the request matches the one stored in the session.

 */

function confirm_sesskey($sesskey=NULL) {

    global $USER;

    if (!empty($USER->ignoresesskey)) {

        return true;

    }

    if (empty($sesskey)) {

        $sesskey = required_param('sesskey', PARAM_RAW);  // Check script parameters

    }

    return (sesskey() === $sesskey);

}

/**

 * Check the session key using {@link confirm_sesskey()},

 * and cause a fatal error if it does not match.

 */

function require_sesskey() {

    if (!confirm_sesskey()) {

        throw new \moodle_exception('invalidsesskey');

    }

}

/**

 * Determine wether the secure flag should be set on cookies

 * @return bool

 */

function is_moodle_cookie_secure() {

    global $CFG;

    if (!isset($CFG->cookiesecure)) {

        return false;

    }

    if (!is_https() and empty($CFG->sslproxy)) {

        return false;

    }

    return !empty($CFG->cookiesecure);

}

/**

 * Sets a moodle cookie with a weakly encrypted username

 *

 * @param string $username to encrypt and place in a cookie, '' means delete current cookie

 * @return void

 */

function set_moodle_cookie($username) {

    global $CFG;

    if (NO_MOODLE_COOKIES) {

        return;

    }

    if (empty($CFG->rememberusername)) {

        // erase current and do not store permanent cookies

        $username = '';

    }

    if ($username === 'guest') {

        // keep previous cookie in case of guest account login

        return;

    }

    $cookiename = 'MOODLEID1_'.$CFG->sessioncookie;

    $cookiesecure = is_moodle_cookie_secure();

    // Delete old cookie.

    setcookie($cookiename, '', time() - HOURSECS, $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $cookiesecure, $CFG->cookiehttponly);

    if ($username !== '') {

        // Set username cookie for 60 days.

        setcookie($cookiename, rc4encrypt($username), time() + (DAYSECS * 60), $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $cookiesecure, $CFG->cookiehttponly);

    }

}

/**

 * Gets a moodle cookie with a weakly encrypted username

 *

 * @return string username

 */

function get_moodle_cookie() {

    global $CFG;

    if (NO_MOODLE_COOKIES) {

        return '';

    }

    if (empty($CFG->rememberusername)) {

        return '';

    }

    $cookiename = 'MOODLEID1_'.$CFG->sessioncookie;

    if (empty($_COOKIE[$cookiename])) {

        return '';

    } else {

        $username = rc4decrypt($_COOKIE[$cookiename]);

        if ($username === 'guest' or $username === 'nobody') {

            // backwards compatibility - we do not set these cookies any more

            $username = '';

        }

        return $username;

    }

}