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1206 lines
43 KiB
1206 lines
43 KiB
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* Session manager class.
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*
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* @package core
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* @copyright 2013 Petr Skoda {@link http://skodak.org}
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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namespace core\session;
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defined('MOODLE_INTERNAL') || die();
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use html_writer;
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/**
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* Session manager, this is the public Moodle API for sessions.
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*
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* Following PHP functions MUST NOT be used directly:
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* - session_start() - not necessary, lib/setup.php starts session automatically,
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* use define('NO_MOODLE_COOKIE', true) if session not necessary.
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* - session_write_close() - use \core\session\manager::write_close() instead.
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* - session_destroy() - use require_logout() instead.
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*
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* @package core
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* @copyright 2013 Petr Skoda {@link http://skodak.org}
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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class manager {
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/** @var int A hard cutoff of maximum stored history */
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const MAXIMUM_STORED_SESSION_HISTORY = 50;
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/** @var int The recent session locks array is reset if there is a time gap more than this value in seconds */
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const SESSION_RESET_GAP_THRESHOLD = 1;
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/** @var handler $handler active session handler instance */
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protected static $handler;
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/** @var bool $sessionactive Is the session active? */
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protected static $sessionactive = null;
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/** @var string $logintokenkey Key used to get and store request protection for login form. */
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protected static $logintokenkey = 'core_auth_login';
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/**
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* Start user session.
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*
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* Note: This is intended to be called only from lib/setup.php!
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*/
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public static function start() {
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global $CFG, $DB, $PERF;
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if (isset(self::$sessionactive)) {
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debugging('Session was already started!', DEBUG_DEVELOPER);
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return;
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}
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// Grab the time before session lock starts.
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$PERF->sessionlock['start'] = microtime(true);
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self::load_handler();
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// Init the session handler only if everything initialised properly in lib/setup.php file
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// and the session is actually required.
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if (empty($DB) or empty($CFG->version) or !defined('NO_MOODLE_COOKIES') or NO_MOODLE_COOKIES or CLI_SCRIPT) {
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self::$sessionactive = false;
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self::init_empty_session();
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return;
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}
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try {
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self::$handler->init();
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self::prepare_cookies();
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$isnewsession = empty($_COOKIE[session_name()]);
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if (!self::$handler->start()) {
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// Could not successfully start/recover session.
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throw new \core\session\exception(get_string('servererror'));
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}
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// Grab the time when session lock starts.
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$PERF->sessionlock['gained'] = microtime(true);
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$PERF->sessionlock['wait'] = $PERF->sessionlock['gained'] - $PERF->sessionlock['start'];
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self::initialise_user_session($isnewsession);
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self::$sessionactive = true; // Set here, so the session can be cleared if the security check fails.
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self::check_security();
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// Link global $USER and $SESSION,
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// this is tricky because PHP does not allow references to references
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// and global keyword uses internally once reference to the $GLOBALS array.
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// The solution is to use the $GLOBALS['USER'] and $GLOBALS['$SESSION']
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// as the main storage of data and put references to $_SESSION.
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$GLOBALS['USER'] = $_SESSION['USER'];
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$_SESSION['USER'] =& $GLOBALS['USER'];
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$GLOBALS['SESSION'] = $_SESSION['SESSION'];
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$_SESSION['SESSION'] =& $GLOBALS['SESSION'];
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} catch (\Exception $ex) {
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self::init_empty_session();
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self::$sessionactive = false;
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throw $ex;
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}
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}
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/**
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* Returns current page performance info.
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*
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* @return array perf info
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*/
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public static function get_performance_info() {
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global $CFG, $PERF;
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if (!session_id()) {
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return array();
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}
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self::load_handler();
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$size = display_size(strlen(session_encode()));
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$handler = get_class(self::$handler);
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$info = array();
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$info['size'] = $size;
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$info['html'] = html_writer::div("Session ($handler): $size", "sessionsize");
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$info['txt'] = "Session ($handler): $size ";
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if (!empty($CFG->debugsessionlock)) {
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$sessionlock = self::get_session_lock_info();
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if (!empty($sessionlock['held'])) {
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// The page displays the footer and the session has been closed.
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$sessionlocktext = "Session lock held: ".number_format($sessionlock['held'], 3)." secs";
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} else {
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// The session hasn't yet been closed and so we assume now with microtime.
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$sessionlockheld = microtime(true) - $PERF->sessionlock['gained'];
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$sessionlocktext = "Session lock open: ".number_format($sessionlockheld, 3)." secs";
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}
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$info['txt'] .= $sessionlocktext;
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$info['html'] .= html_writer::div($sessionlocktext, "sessionlockstart");
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$sessionlockwaittext = "Session lock wait: ".number_format($sessionlock['wait'], 3)." secs";
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$info['txt'] .= $sessionlockwaittext;
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$info['html'] .= html_writer::div($sessionlockwaittext, "sessionlockwait");
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}
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return $info;
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}
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/**
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* Get fully qualified name of session handler class.
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*
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* @return string The name of the handler class
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*/
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public static function get_handler_class() {
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global $CFG, $DB;
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if (PHPUNIT_TEST) {
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return '\core\session\file';
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} else if (!empty($CFG->session_handler_class)) {
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return $CFG->session_handler_class;
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} else if (!empty($CFG->dbsessions) and $DB->session_lock_supported()) {
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return '\core\session\database';
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}
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return '\core\session\file';
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}
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/**
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* Create handler instance.
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*/
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protected static function load_handler() {
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if (self::$handler) {
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return;
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}
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// Find out which handler to use.
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$class = self::get_handler_class();
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self::$handler = new $class();
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}
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/**
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* Empty current session, fill it with not-logged-in user info.
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*
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* This is intended for installation scripts, unit tests and other
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* special areas. Do NOT use for logout and session termination
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* in normal requests!
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*/
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public static function init_empty_session() {
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global $CFG;
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if (isset($GLOBALS['SESSION']->notifications)) {
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// Backup notifications. These should be preserved across session changes until the user fetches and clears them.
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$notifications = $GLOBALS['SESSION']->notifications;
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}
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$GLOBALS['SESSION'] = new \stdClass();
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$GLOBALS['USER'] = new \stdClass();
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$GLOBALS['USER']->id = 0;
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if (!empty($notifications)) {
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// Restore notifications.
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$GLOBALS['SESSION']->notifications = $notifications;
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}
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if (isset($CFG->mnet_localhost_id)) {
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$GLOBALS['USER']->mnethostid = $CFG->mnet_localhost_id;
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} else {
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// Not installed yet, the future host id will be most probably 1.
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$GLOBALS['USER']->mnethostid = 1;
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}
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// Link global $USER and $SESSION.
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$_SESSION = array();
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$_SESSION['USER'] =& $GLOBALS['USER'];
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$_SESSION['SESSION'] =& $GLOBALS['SESSION'];
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}
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/**
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* Make sure all cookie and session related stuff is configured properly before session start.
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*/
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protected static function prepare_cookies() {
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global $CFG;
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$cookiesecure = is_moodle_cookie_secure();
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if (!isset($CFG->cookiehttponly)) {
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$CFG->cookiehttponly = 0;
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}
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// Set sessioncookie variable if it isn't already.
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if (!isset($CFG->sessioncookie)) {
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$CFG->sessioncookie = '';
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}
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$sessionname = 'MoodleSession'.$CFG->sessioncookie;
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// Make sure cookie domain makes sense for this wwwroot.
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if (!isset($CFG->sessioncookiedomain)) {
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$CFG->sessioncookiedomain = '';
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} else if ($CFG->sessioncookiedomain !== '') {
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$host = parse_url($CFG->wwwroot, PHP_URL_HOST);
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if ($CFG->sessioncookiedomain !== $host) {
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if (substr($CFG->sessioncookiedomain, 0, 1) === '.') {
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if (!preg_match('|^.*'.preg_quote($CFG->sessioncookiedomain, '|').'$|', $host)) {
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// Invalid domain - it must be end part of host.
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$CFG->sessioncookiedomain = '';
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}
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} else {
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if (!preg_match('|^.*\.'.preg_quote($CFG->sessioncookiedomain, '|').'$|', $host)) {
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// Invalid domain - it must be end part of host.
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$CFG->sessioncookiedomain = '';
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}
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}
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}
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}
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// Make sure the cookiepath is valid for this wwwroot or autodetect if not specified.
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if (!isset($CFG->sessioncookiepath)) {
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$CFG->sessioncookiepath = '';
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}
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if ($CFG->sessioncookiepath !== '/') {
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$path = parse_url($CFG->wwwroot, PHP_URL_PATH).'/';
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if ($CFG->sessioncookiepath === '') {
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$CFG->sessioncookiepath = $path;
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} else {
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if (strpos($path, $CFG->sessioncookiepath) !== 0 or substr($CFG->sessioncookiepath, -1) !== '/') {
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$CFG->sessioncookiepath = $path;
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}
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}
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}
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// Discard session ID from POST, GET and globals to tighten security,
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// this is session fixation prevention.
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unset($GLOBALS[$sessionname]);
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unset($_GET[$sessionname]);
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unset($_POST[$sessionname]);
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unset($_REQUEST[$sessionname]);
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// Compatibility hack for non-browser access to our web interface.
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if (!empty($_COOKIE[$sessionname]) && $_COOKIE[$sessionname] == "deleted") {
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unset($_COOKIE[$sessionname]);
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}
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// Set configuration.
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session_name($sessionname);
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session_set_cookie_params(0, $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $cookiesecure, $CFG->cookiehttponly);
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ini_set('session.use_trans_sid', '0');
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ini_set('session.use_only_cookies', '1');
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ini_set('session.hash_function', '0'); // For now MD5 - we do not have room for sha-1 in sessions table.
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ini_set('session.use_strict_mode', '0'); // We have custom protection in session init.
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ini_set('session.serialize_handler', 'php'); // We can move to 'php_serialize' after we require PHP 5.5.4 form Moodle.
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// Moodle does normal session timeouts, this is for leftovers only.
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ini_set('session.gc_probability', 1);
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ini_set('session.gc_divisor', 1000);
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ini_set('session.gc_maxlifetime', 60*60*24*4);
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}
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/**
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* Initialise $_SESSION, handles google access
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* and sets up not-logged-in user properly.
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*
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* WARNING: $USER and $SESSION are set up later, do not use them yet!
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*
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* @param bool $newsid is this a new session in first http request?
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*/
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protected static function initialise_user_session($newsid) {
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global $CFG, $DB;
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$sid = session_id();
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if (!$sid) {
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// No session, very weird.
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error_log('Missing session ID, session not started!');
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self::init_empty_session();
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return;
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}
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if (!$record = $DB->get_record('sessions', array('sid'=>$sid), 'id, sid, state, userid, lastip, timecreated, timemodified')) {
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if (!$newsid) {
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if (!empty($_SESSION['USER']->id)) {
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// This should not happen, just log it, we MUST not produce any output here!
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error_log("Cannot find session record $sid for user ".$_SESSION['USER']->id.", creating new session.");
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}
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// Prevent session fixation attacks.
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session_regenerate_id(true);
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}
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$_SESSION = array();
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}
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unset($sid);
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if (isset($_SESSION['USER']->id)) {
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if (!empty($_SESSION['USER']->realuser)) {
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$userid = $_SESSION['USER']->realuser;
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} else {
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$userid = $_SESSION['USER']->id;
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}
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// Verify timeout first.
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$maxlifetime = $CFG->sessiontimeout;
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$timeout = false;
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if (isguestuser($userid) or empty($userid)) {
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// Ignore guest and not-logged in timeouts, there is very little risk here.
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$timeout = false;
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} else if ($record->timemodified < time() - $maxlifetime) {
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$timeout = true;
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$authsequence = get_enabled_auth_plugins(); // Auths, in sequence.
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foreach ($authsequence as $authname) {
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$authplugin = get_auth_plugin($authname);
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if ($authplugin->ignore_timeout_hook($_SESSION['USER'], $record->sid, $record->timecreated, $record->timemodified)) {
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$timeout = false;
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break;
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}
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}
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}
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if ($timeout) {
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session_regenerate_id(true);
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$_SESSION = array();
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$DB->delete_records('sessions', array('id'=>$record->id));
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} else {
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// Update session tracking record.
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$update = new \stdClass();
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$updated = false;
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if ($record->userid != $userid) {
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$update->userid = $record->userid = $userid;
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$updated = true;
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}
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$ip = getremoteaddr();
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if ($record->lastip != $ip) {
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$update->lastip = $record->lastip = $ip;
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$updated = true;
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}
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$updatefreq = empty($CFG->session_update_timemodified_frequency) ? 20 : $CFG->session_update_timemodified_frequency;
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if ($record->timemodified == $record->timecreated) {
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// Always do first update of existing record.
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$update->timemodified = $record->timemodified = time();
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$updated = true;
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} else if ($record->timemodified < time() - $updatefreq) {
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// Update the session modified flag only once every 20 seconds.
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$update->timemodified = $record->timemodified = time();
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$updated = true;
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}
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if ($updated) {
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$update->id = $record->id;
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$DB->update_record('sessions', $update);
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}
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return;
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}
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} else {
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if ($record) {
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// This happens when people switch session handlers...
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session_regenerate_id(true);
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$_SESSION = array();
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$DB->delete_records('sessions', array('id'=>$record->id));
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}
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}
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unset($record);
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$timedout = false;
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if (!isset($_SESSION['SESSION'])) {
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$_SESSION['SESSION'] = new \stdClass();
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if (!$newsid) {
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$timedout = true;
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}
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}
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$user = null;
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if (!empty($CFG->opentogoogle)) {
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if (\core_useragent::is_web_crawler()) {
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$user = guest_user();
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}
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$referer = get_local_referer(false);
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if (!empty($CFG->guestloginbutton) and !$user and !empty($referer)) {
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// Automatically log in users coming from search engine results.
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if (strpos($referer, 'google') !== false ) {
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$user = guest_user();
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} else if (strpos($referer, 'altavista') !== false ) {
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$user = guest_user();
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}
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}
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}
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// Setup $USER and insert the session tracking record.
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if ($user) {
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self::set_user($user);
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self::add_session_record($user->id);
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} else {
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self::init_empty_session();
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self::add_session_record(0);
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}
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if ($timedout) {
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$_SESSION['SESSION']->has_timed_out = true;
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}
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}
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/**
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* Insert new empty session record.
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* @param int $userid
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* @return \stdClass the new record
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*/
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protected static function add_session_record($userid) {
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global $DB;
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$record = new \stdClass();
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$record->state = 0;
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$record->sid = session_id();
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$record->sessdata = null;
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$record->userid = $userid;
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$record->timecreated = $record->timemodified = time();
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$record->firstip = $record->lastip = getremoteaddr();
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$record->id = $DB->insert_record('sessions', $record);
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return $record;
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}
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/**
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* Do various session security checks.
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*
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* WARNING: $USER and $SESSION are set up later, do not use them yet!
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* @throws \core\session\exception
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*/
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protected static function check_security() {
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global $CFG;
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if (!empty($_SESSION['USER']->id) and !empty($CFG->tracksessionip)) {
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// Make sure current IP matches the one for this session.
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$remoteaddr = getremoteaddr();
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if (empty($_SESSION['USER']->sessionip)) {
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$_SESSION['USER']->sessionip = $remoteaddr;
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}
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if ($_SESSION['USER']->sessionip != $remoteaddr) {
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// This is a security feature - terminate the session in case of any doubt.
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self::terminate_current();
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throw new exception('sessionipnomatch2', 'error');
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}
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}
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}
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/**
|
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* Login user, to be called from complete_user_login() only.
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* @param \stdClass $user
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*/
|
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public static function login_user(\stdClass $user) {
|
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global $DB;
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// Regenerate session id and delete old session,
|
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// this helps prevent session fixation attacks from the same domain.
|
|
|
|
$sid = session_id();
|
|
session_regenerate_id(true);
|
|
$DB->delete_records('sessions', array('sid'=>$sid));
|
|
self::add_session_record($user->id);
|
|
|
|
// Let enrol plugins deal with new enrolments if necessary.
|
|
enrol_check_plugins($user);
|
|
|
|
// Setup $USER object.
|
|
self::set_user($user);
|
|
}
|
|
|
|
/**
|
|
* Terminate current user session.
|
|
* @return void
|
|
*/
|
|
public static function terminate_current() {
|
|
global $DB;
|
|
|
|
if (!self::$sessionactive) {
|
|
self::init_empty_session();
|
|
self::$sessionactive = false;
|
|
return;
|
|
}
|
|
|
|
try {
|
|
$DB->delete_records('external_tokens', array('sid'=>session_id(), 'tokentype'=>EXTERNAL_TOKEN_EMBEDDED));
|
|
} catch (\Exception $ignored) {
|
|
// Probably install/upgrade - ignore this problem.
|
|
}
|
|
|
|
// Initialize variable to pass-by-reference to headers_sent(&$file, &$line).
|
|
$file = null;
|
|
$line = null;
|
|
if (headers_sent($file, $line)) {
|
|
error_log('Cannot terminate session properly - headers were already sent in file: '.$file.' on line '.$line);
|
|
}
|
|
|
|
// Write new empty session and make sure the old one is deleted.
|
|
$sid = session_id();
|
|
session_regenerate_id(true);
|
|
$DB->delete_records('sessions', array('sid'=>$sid));
|
|
self::init_empty_session();
|
|
self::add_session_record($_SESSION['USER']->id); // Do not use $USER here because it may not be set up yet.
|
|
session_write_close();
|
|
self::$sessionactive = false;
|
|
}
|
|
|
|
/**
|
|
* No more changes in session expected.
|
|
* Unblocks the sessions, other scripts may start executing in parallel.
|
|
*/
|
|
public static function write_close() {
|
|
global $PERF;
|
|
|
|
if (self::$sessionactive) {
|
|
// Grab the time when session lock is released.
|
|
$PERF->sessionlock['released'] = microtime(true);
|
|
if (!empty($PERF->sessionlock['gained'])) {
|
|
$PERF->sessionlock['held'] = $PERF->sessionlock['released'] - $PERF->sessionlock['gained'];
|
|
}
|
|
$PERF->sessionlock['url'] = me();
|
|
self::update_recent_session_locks($PERF->sessionlock);
|
|
self::sessionlock_debugging();
|
|
}
|
|
|
|
if (version_compare(PHP_VERSION, '5.6.0', '>=')) {
|
|
// More control over whether session data
|
|
// is persisted or not.
|
|
if (self::$sessionactive && session_id()) {
|
|
// Write session and release lock only if
|
|
// indication session start was clean.
|
|
session_write_close();
|
|
} else {
|
|
// Otherwise, if possibile lock exists want
|
|
// to clear it, but do not write session.
|
|
@session_abort();
|
|
}
|
|
} else {
|
|
// Any indication session was started, attempt
|
|
// to close it.
|
|
if (self::$sessionactive || session_id()) {
|
|
session_write_close();
|
|
}
|
|
}
|
|
self::$sessionactive = false;
|
|
}
|
|
|
|
/**
|
|
* Does the PHP session with given id exist?
|
|
*
|
|
* The session must exist both in session table and actual
|
|
* session backend and the session must not be timed out.
|
|
*
|
|
* Timeout evaluation is simplified, the auth hooks are not executed.
|
|
*
|
|
* @param string $sid
|
|
* @return bool
|
|
*/
|
|
public static function session_exists($sid) {
|
|
global $DB, $CFG;
|
|
|
|
if (empty($CFG->version)) {
|
|
// Not installed yet, do not try to access database.
|
|
return false;
|
|
}
|
|
|
|
// Note: add sessions->state checking here if it gets implemented.
|
|
if (!$record = $DB->get_record('sessions', array('sid' => $sid), 'id, userid, timemodified')) {
|
|
return false;
|
|
}
|
|
|
|
if (empty($record->userid) or isguestuser($record->userid)) {
|
|
// Ignore guest and not-logged-in timeouts, there is very little risk here.
|
|
} else if ($record->timemodified < time() - $CFG->sessiontimeout) {
|
|
return false;
|
|
}
|
|
|
|
// There is no need the existence of handler storage in public API.
|
|
self::load_handler();
|
|
return self::$handler->session_exists($sid);
|
|
}
|
|
|
|
/**
|
|
* Fake last access for given session, this prevents session timeout.
|
|
* @param string $sid
|
|
*/
|
|
public static function touch_session($sid) {
|
|
global $DB;
|
|
|
|
// Timeouts depend on core sessions table only, no need to update anything in external stores.
|
|
|
|
$sql = "UPDATE {sessions} SET timemodified = :now WHERE sid = :sid";
|
|
$DB->execute($sql, array('now'=>time(), 'sid'=>$sid));
|
|
}
|
|
|
|
/**
|
|
* Terminate all sessions unconditionally.
|
|
*/
|
|
public static function kill_all_sessions() {
|
|
global $DB;
|
|
|
|
self::terminate_current();
|
|
|
|
self::load_handler();
|
|
self::$handler->kill_all_sessions();
|
|
|
|
try {
|
|
$DB->delete_records('sessions');
|
|
} catch (\dml_exception $ignored) {
|
|
// Do not show any warnings - might be during upgrade/installation.
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Terminate give session unconditionally.
|
|
* @param string $sid
|
|
*/
|
|
public static function kill_session($sid) {
|
|
global $DB;
|
|
|
|
self::load_handler();
|
|
|
|
if ($sid === session_id()) {
|
|
self::write_close();
|
|
}
|
|
|
|
self::$handler->kill_session($sid);
|
|
|
|
$DB->delete_records('sessions', array('sid'=>$sid));
|
|
}
|
|
|
|
/**
|
|
* Terminate all sessions of given user unconditionally.
|
|
* @param int $userid
|
|
* @param string $keepsid keep this sid if present
|
|
*/
|
|
public static function kill_user_sessions($userid, $keepsid = null) {
|
|
global $DB;
|
|
|
|
$sessions = $DB->get_records('sessions', array('userid'=>$userid), 'id DESC', 'id, sid');
|
|
foreach ($sessions as $session) {
|
|
if ($keepsid and $keepsid === $session->sid) {
|
|
continue;
|
|
}
|
|
self::kill_session($session->sid);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Terminate other sessions of current user depending
|
|
* on $CFG->limitconcurrentlogins restriction.
|
|
*
|
|
* This is expected to be called right after complete_user_login().
|
|
*
|
|
* NOTE:
|
|
* * Do not use from SSO auth plugins, this would not work.
|
|
* * Do not use from web services because they do not have sessions.
|
|
*
|
|
* @param int $userid
|
|
* @param string $sid session id to be always keep, usually the current one
|
|
* @return void
|
|
*/
|
|
public static function apply_concurrent_login_limit($userid, $sid = null) {
|
|
global $CFG, $DB;
|
|
|
|
// NOTE: the $sid parameter is here mainly to allow testing,
|
|
// in most cases it should be current session id.
|
|
|
|
if (isguestuser($userid) or empty($userid)) {
|
|
// This applies to real users only!
|
|
return;
|
|
}
|
|
|
|
if (empty($CFG->limitconcurrentlogins) or $CFG->limitconcurrentlogins < 0) {
|
|
return;
|
|
}
|
|
|
|
$count = $DB->count_records('sessions', array('userid' => $userid));
|
|
|
|
if ($count <= $CFG->limitconcurrentlogins) {
|
|
return;
|
|
}
|
|
|
|
$i = 0;
|
|
$select = "userid = :userid";
|
|
$params = array('userid' => $userid);
|
|
if ($sid) {
|
|
if ($DB->record_exists('sessions', array('sid' => $sid, 'userid' => $userid))) {
|
|
$select .= " AND sid <> :sid";
|
|
$params['sid'] = $sid;
|
|
$i = 1;
|
|
}
|
|
}
|
|
|
|
$sessions = $DB->get_records_select('sessions', $select, $params, 'timecreated DESC', 'id, sid');
|
|
foreach ($sessions as $session) {
|
|
$i++;
|
|
if ($i <= $CFG->limitconcurrentlogins) {
|
|
continue;
|
|
}
|
|
self::kill_session($session->sid);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Set current user.
|
|
*
|
|
* @param \stdClass $user record
|
|
*/
|
|
public static function set_user(\stdClass $user) {
|
|
global $ADMIN;
|
|
$GLOBALS['USER'] = $user;
|
|
unset($GLOBALS['USER']->description); // Conserve memory.
|
|
unset($GLOBALS['USER']->password); // Improve security.
|
|
if (isset($GLOBALS['USER']->lang)) {
|
|
// Make sure it is a valid lang pack name.
|
|
$GLOBALS['USER']->lang = clean_param($GLOBALS['USER']->lang, PARAM_LANG);
|
|
}
|
|
|
|
// Relink session with global $USER just in case it got unlinked somehow.
|
|
$_SESSION['USER'] =& $GLOBALS['USER'];
|
|
|
|
// Nullify the $ADMIN tree global. If we're changing users, then this is now stale and must be generated again if needed.
|
|
$ADMIN = null;
|
|
|
|
// Init session key.
|
|
sesskey();
|
|
}
|
|
|
|
/**
|
|
* Periodic timed-out session cleanup.
|
|
*/
|
|
public static function gc() {
|
|
global $CFG, $DB;
|
|
|
|
// This may take a long time...
|
|
\core_php_time_limit::raise();
|
|
|
|
$maxlifetime = $CFG->sessiontimeout;
|
|
|
|
try {
|
|
// Kill all sessions of deleted and suspended users without any hesitation.
|
|
$rs = $DB->get_recordset_select('sessions', "userid IN (SELECT id FROM {user} WHERE deleted <> 0 OR suspended <> 0)", array(), 'id DESC', 'id, sid');
|
|
foreach ($rs as $session) {
|
|
self::kill_session($session->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
// Kill sessions of users with disabled plugins.
|
|
$auth_sequence = get_enabled_auth_plugins(true);
|
|
$auth_sequence = array_flip($auth_sequence);
|
|
unset($auth_sequence['nologin']); // No login means user cannot login.
|
|
$auth_sequence = array_flip($auth_sequence);
|
|
|
|
list($notplugins, $params) = $DB->get_in_or_equal($auth_sequence, SQL_PARAMS_QM, '', false);
|
|
$rs = $DB->get_recordset_select('sessions', "userid IN (SELECT id FROM {user} WHERE auth $notplugins)", $params, 'id DESC', 'id, sid');
|
|
foreach ($rs as $session) {
|
|
self::kill_session($session->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
// Now get a list of time-out candidates - real users only.
|
|
$sql = "SELECT u.*, s.sid, s.timecreated AS s_timecreated, s.timemodified AS s_timemodified
|
|
FROM {user} u
|
|
JOIN {sessions} s ON s.userid = u.id
|
|
WHERE s.timemodified < :purgebefore AND u.id <> :guestid";
|
|
$params = array('purgebefore' => (time() - $maxlifetime), 'guestid'=>$CFG->siteguest);
|
|
|
|
$authplugins = array();
|
|
foreach ($auth_sequence as $authname) {
|
|
$authplugins[$authname] = get_auth_plugin($authname);
|
|
}
|
|
$rs = $DB->get_recordset_sql($sql, $params);
|
|
foreach ($rs as $user) {
|
|
foreach ($authplugins as $authplugin) {
|
|
/** @var \auth_plugin_base $authplugin*/
|
|
if ($authplugin->ignore_timeout_hook($user, $user->sid, $user->s_timecreated, $user->s_timemodified)) {
|
|
continue 2;
|
|
}
|
|
}
|
|
self::kill_session($user->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
// Delete expired sessions for guest user account, give them larger timeout, there is no security risk here.
|
|
$params = array('purgebefore' => (time() - ($maxlifetime * 5)), 'guestid'=>$CFG->siteguest);
|
|
$rs = $DB->get_recordset_select('sessions', 'userid = :guestid AND timemodified < :purgebefore', $params, 'id DESC', 'id, sid');
|
|
foreach ($rs as $session) {
|
|
self::kill_session($session->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
// Delete expired sessions for userid = 0 (not logged in), better kill them asap to release memory.
|
|
$params = array('purgebefore' => (time() - $maxlifetime));
|
|
$rs = $DB->get_recordset_select('sessions', 'userid = 0 AND timemodified < :purgebefore', $params, 'id DESC', 'id, sid');
|
|
foreach ($rs as $session) {
|
|
self::kill_session($session->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
// Cleanup letfovers from the first browser access because it may set multiple cookies and then use only one.
|
|
$params = array('purgebefore' => (time() - 60*3));
|
|
$rs = $DB->get_recordset_select('sessions', 'userid = 0 AND timemodified = timecreated AND timemodified < :purgebefore', $params, 'id ASC', 'id, sid');
|
|
foreach ($rs as $session) {
|
|
self::kill_session($session->sid);
|
|
}
|
|
$rs->close();
|
|
|
|
} catch (\Exception $ex) {
|
|
debugging('Error gc-ing sessions: '.$ex->getMessage(), DEBUG_NORMAL, $ex->getTrace());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Is current $USER logged-in-as somebody else?
|
|
* @return bool
|
|
*/
|
|
public static function is_loggedinas() {
|
|
return !empty($GLOBALS['USER']->realuser);
|
|
}
|
|
|
|
/**
|
|
* Returns the $USER object ignoring current login-as session
|
|
* @return \stdClass user object
|
|
*/
|
|
public static function get_realuser() {
|
|
if (self::is_loggedinas()) {
|
|
return $_SESSION['REALUSER'];
|
|
} else {
|
|
return $GLOBALS['USER'];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Login as another user - no security checks here.
|
|
* @param int $userid
|
|
* @param \context $context
|
|
* @param bool $generateevent Set to false to prevent the loginas event to be generated
|
|
* @return void
|
|
*/
|
|
public static function loginas($userid, \context $context, $generateevent = true) {
|
|
global $USER;
|
|
|
|
if (self::is_loggedinas()) {
|
|
return;
|
|
}
|
|
|
|
// Switch to fresh new $_SESSION.
|
|
$_SESSION = array();
|
|
$_SESSION['REALSESSION'] = clone($GLOBALS['SESSION']);
|
|
$GLOBALS['SESSION'] = new \stdClass();
|
|
$_SESSION['SESSION'] =& $GLOBALS['SESSION'];
|
|
|
|
// Create the new $USER object with all details and reload needed capabilities.
|
|
$_SESSION['REALUSER'] = clone($GLOBALS['USER']);
|
|
$user = get_complete_user_data('id', $userid);
|
|
$user->realuser = $_SESSION['REALUSER']->id;
|
|
$user->loginascontext = $context;
|
|
|
|
// Let enrol plugins deal with new enrolments if necessary.
|
|
enrol_check_plugins($user);
|
|
|
|
if ($generateevent) {
|
|
// Create event before $USER is updated.
|
|
$event = \core\event\user_loggedinas::create(
|
|
array(
|
|
'objectid' => $USER->id,
|
|
'context' => $context,
|
|
'relateduserid' => $userid,
|
|
'other' => array(
|
|
'originalusername' => fullname($USER, true),
|
|
'loggedinasusername' => fullname($user, true)
|
|
)
|
|
)
|
|
);
|
|
}
|
|
|
|
// Set up global $USER.
|
|
\core\session\manager::set_user($user);
|
|
|
|
if ($generateevent) {
|
|
$event->trigger();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Add a JS session keepalive to the page.
|
|
*
|
|
* A JS session keepalive script will be called to update the session modification time every $frequency seconds.
|
|
*
|
|
* Upon failure, the specified error message will be shown to the user.
|
|
*
|
|
* @param string $identifier The string identifier for the message to show on failure.
|
|
* @param string $component The string component for the message to show on failure.
|
|
* @param int $frequency The update frequency in seconds.
|
|
* @throws coding_exception IF the frequency is longer than the session lifetime.
|
|
*/
|
|
public static function keepalive($identifier = 'sessionerroruser', $component = 'error', $frequency = null) {
|
|
global $CFG, $PAGE;
|
|
|
|
if ($frequency) {
|
|
if ($frequency > $CFG->sessiontimeout) {
|
|
// Sanity check the frequency.
|
|
throw new \coding_exception('Keepalive frequency is longer than the session lifespan.');
|
|
}
|
|
} else {
|
|
// A frequency of sessiontimeout / 3 allows for one missed request whilst still preserving the session.
|
|
$frequency = $CFG->sessiontimeout / 3;
|
|
}
|
|
|
|
// Add the session keepalive script to the list of page output requirements.
|
|
$sessionkeepaliveurl = new \moodle_url('/lib/sessionkeepalive_ajax.php');
|
|
$PAGE->requires->string_for_js($identifier, $component);
|
|
$PAGE->requires->yui_module('moodle-core-checknet', 'M.core.checknet.init', array(array(
|
|
// The JS config takes this is milliseconds rather than seconds.
|
|
'frequency' => $frequency * 1000,
|
|
'message' => array($identifier, $component),
|
|
'uri' => $sessionkeepaliveurl->out(),
|
|
)));
|
|
}
|
|
|
|
/**
|
|
* Generate a new login token and store it in the session.
|
|
*
|
|
* @return array The current login state.
|
|
*/
|
|
private static function create_login_token() {
|
|
global $SESSION;
|
|
|
|
$state = [
|
|
'token' => random_string(32),
|
|
'created' => time() // Server time - not user time.
|
|
];
|
|
|
|
if (!isset($SESSION->logintoken)) {
|
|
$SESSION->logintoken = [];
|
|
}
|
|
|
|
// Overwrite any previous values.
|
|
$SESSION->logintoken[self::$logintokenkey] = $state;
|
|
|
|
return $state;
|
|
}
|
|
|
|
/**
|
|
* Get the current login token or generate a new one.
|
|
*
|
|
* All login forms generated from Moodle must include a login token
|
|
* named "logintoken" with the value being the result of this function.
|
|
* Logins will be rejected if they do not include this token as well as
|
|
* the username and password fields.
|
|
*
|
|
* @return string The current login token.
|
|
*/
|
|
public static function get_login_token() {
|
|
global $CFG, $SESSION;
|
|
|
|
$state = false;
|
|
|
|
if (!isset($SESSION->logintoken)) {
|
|
$SESSION->logintoken = [];
|
|
}
|
|
|
|
if (array_key_exists(self::$logintokenkey, $SESSION->logintoken)) {
|
|
$state = $SESSION->logintoken[self::$logintokenkey];
|
|
}
|
|
if (empty($state)) {
|
|
$state = self::create_login_token();
|
|
}
|
|
|
|
// Check token lifespan.
|
|
if ($state['created'] < (time() - $CFG->sessiontimeout)) {
|
|
$state = self::create_login_token();
|
|
}
|
|
|
|
// Return the current session login token.
|
|
if (array_key_exists('token', $state)) {
|
|
return $state['token'];
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Check the submitted value against the stored login token.
|
|
*
|
|
* @param mixed $token The value submitted in the login form that we are validating.
|
|
* If false is passed for the token, this function will always return true.
|
|
* @return boolean If the submitted token is valid.
|
|
*/
|
|
public static function validate_login_token($token = false) {
|
|
global $CFG;
|
|
|
|
if (!empty($CFG->alternateloginurl) || !empty($CFG->disablelogintoken)) {
|
|
// An external login page cannot generate the login token we need to protect CSRF on
|
|
// login requests.
|
|
// Other custom login workflows may skip this check by setting disablelogintoken in config.
|
|
return true;
|
|
}
|
|
if ($token === false) {
|
|
// authenticate_user_login is a core function was extended to validate tokens.
|
|
// For existing uses other than the login form it does not
|
|
// validate that a token was generated.
|
|
// Some uses that do not validate the token are login/token.php,
|
|
// or an auth plugin like auth/ldap/auth.php.
|
|
return true;
|
|
}
|
|
|
|
$currenttoken = self::get_login_token();
|
|
|
|
// We need to clean the login token so the old one is not valid again.
|
|
self::create_login_token();
|
|
|
|
if ($currenttoken !== $token) {
|
|
// Fail the login.
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Get the recent session locks array.
|
|
*
|
|
* @return array Recent session locks array.
|
|
*/
|
|
public static function get_recent_session_locks() {
|
|
global $SESSION;
|
|
|
|
if (!isset($SESSION->recentsessionlocks)) {
|
|
// This will hold the pages that blocks other page.
|
|
$SESSION->recentsessionlocks = array();
|
|
}
|
|
|
|
return $SESSION->recentsessionlocks;
|
|
}
|
|
|
|
/**
|
|
* Updates the recent session locks.
|
|
*
|
|
* This function will store session lock info of all the pages visited.
|
|
*
|
|
* @param array $sessionlock Session lock array.
|
|
*/
|
|
public static function update_recent_session_locks($sessionlock) {
|
|
global $CFG, $SESSION;
|
|
|
|
if (empty($CFG->debugsessionlock)) {
|
|
return;
|
|
}
|
|
|
|
$SESSION->recentsessionlocks = self::get_recent_session_locks();
|
|
array_push($SESSION->recentsessionlocks, $sessionlock);
|
|
|
|
self::cleanup_recent_session_locks();
|
|
}
|
|
|
|
/**
|
|
* Reset recent session locks array if there is a time gap more than SESSION_RESET_GAP_THRESHOLD.
|
|
*/
|
|
public static function cleanup_recent_session_locks() {
|
|
global $SESSION;
|
|
|
|
$locks = self::get_recent_session_locks();
|
|
|
|
if (count($locks) > self::MAXIMUM_STORED_SESSION_HISTORY) {
|
|
// Keep the last MAXIMUM_STORED_SESSION_HISTORY locks and ignore the rest.
|
|
$locks = array_slice($locks, -1 * self::MAXIMUM_STORED_SESSION_HISTORY);
|
|
}
|
|
|
|
if (count($locks) > 2) {
|
|
for ($i = count($locks) - 1; $i > 0; $i--) {
|
|
// Calculate the gap between session locks.
|
|
$gap = $locks[$i]['released'] - $locks[$i - 1]['start'];
|
|
if ($gap >= self::SESSION_RESET_GAP_THRESHOLD) {
|
|
// Remove previous locks if the gap is 1 second or more.
|
|
$SESSION->recentsessionlocks = array_slice($locks, $i);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Get the page that blocks other pages at a specific timestamp.
|
|
*
|
|
* Look for a page whose lock was gained before that timestamp, and released after that timestamp.
|
|
*
|
|
* @param float $time Time before session lock starts.
|
|
* @return array|null
|
|
*/
|
|
public static function get_locked_page_at($time) {
|
|
$recentsessionlocks = self::get_recent_session_locks();
|
|
foreach ($recentsessionlocks as $recentsessionlock) {
|
|
if ($time >= $recentsessionlock['gained'] &&
|
|
$time <= $recentsessionlock['released']) {
|
|
return $recentsessionlock;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Display the page which blocks other pages.
|
|
*
|
|
* @return string
|
|
*/
|
|
public static function display_blocking_page() {
|
|
global $PERF;
|
|
|
|
$page = self::get_locked_page_at($PERF->sessionlock['start']);
|
|
$output = "Script ".me()." was blocked for ";
|
|
$output .= number_format($PERF->sessionlock['wait'], 3);
|
|
if ($page != null) {
|
|
$output .= " second(s) by script: ";
|
|
$output .= $page['url'];
|
|
} else {
|
|
$output .= " second(s) by an unknown script.";
|
|
}
|
|
|
|
return $output;
|
|
}
|
|
|
|
/**
|
|
* Get session lock info of the current page.
|
|
*
|
|
* @return array
|
|
*/
|
|
public static function get_session_lock_info() {
|
|
global $PERF;
|
|
|
|
if (!isset($PERF->sessionlock)) {
|
|
return null;
|
|
}
|
|
return $PERF->sessionlock;
|
|
}
|
|
|
|
/**
|
|
* Display debugging info about slow and blocked script.
|
|
*/
|
|
public static function sessionlock_debugging() {
|
|
global $CFG, $PERF;
|
|
|
|
if (!empty($CFG->debugsessionlock)) {
|
|
if (isset($PERF->sessionlock['held']) && $PERF->sessionlock['held'] > $CFG->debugsessionlock) {
|
|
debugging("Script ".me()." locked the session for ".number_format($PERF->sessionlock['held'], 3)
|
|
." seconds, it should close the session using \core\session\manager::write_close().", DEBUG_NORMAL);
|
|
}
|
|
|
|
if (isset($PERF->sessionlock['wait']) && $PERF->sessionlock['wait'] > $CFG->debugsessionlock) {
|
|
$output = self::display_blocking_page();
|
|
debugging($output, DEBUG_DEVELOPER);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|