1: <?php
  2: /**
  3:  * Session class for CakePHP.
  4:  *
  5:  * CakePHP abstracts the handling of sessions.
  6:  * There are several convenient methods to access session information.
  7:  * This class is the implementation of those methods.
  8:  * They are mostly used by the Session Component.
  9:  *
 10:  * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 11:  * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 12:  *
 13:  * Licensed under The MIT License
 14:  * For full copyright and license information, please see the LICENSE.txt
 15:  * Redistributions of files must retain the above copyright notice.
 16:  *
 17:  * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 18:  * @link          http://cakephp.org CakePHP(tm) Project
 19:  * @package       Cake.Model.Datasource
 20:  * @since         CakePHP(tm) v .0.10.0.1222
 21:  * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 22:  */
 23: 
 24: App::uses('Hash', 'Utility');
 25: App::uses('Security', 'Utility');
 26: 
 27: /**
 28:  * Session class for CakePHP.
 29:  *
 30:  * CakePHP abstracts the handling of sessions. There are several convenient methods to access session information.
 31:  * This class is the implementation of those methods. They are mostly used by the Session Component.
 32:  *
 33:  * @package       Cake.Model.Datasource
 34:  */
 35: class CakeSession {
 36: 
 37: /**
 38:  * True if the Session is still valid
 39:  *
 40:  * @var bool
 41:  */
 42:     public static $valid = false;
 43: 
 44: /**
 45:  * Error messages for this session
 46:  *
 47:  * @var array
 48:  */
 49:     public static $error = false;
 50: 
 51: /**
 52:  * User agent string
 53:  *
 54:  * @var string
 55:  */
 56:     protected static $_userAgent = '';
 57: 
 58: /**
 59:  * Path to where the session is active.
 60:  *
 61:  * @var string
 62:  */
 63:     public static $path = '/';
 64: 
 65: /**
 66:  * Error number of last occurred error
 67:  *
 68:  * @var int
 69:  */
 70:     public static $lastError = null;
 71: 
 72: /**
 73:  * Start time for this session.
 74:  *
 75:  * @var int
 76:  */
 77:     public static $time = false;
 78: 
 79: /**
 80:  * Cookie lifetime
 81:  *
 82:  * @var int
 83:  */
 84:     public static $cookieLifeTime;
 85: 
 86: /**
 87:  * Time when this session becomes invalid.
 88:  *
 89:  * @var int
 90:  */
 91:     public static $sessionTime = false;
 92: 
 93: /**
 94:  * Current Session id
 95:  *
 96:  * @var string
 97:  */
 98:     public static $id = null;
 99: 
100: /**
101:  * Hostname
102:  *
103:  * @var string
104:  */
105:     public static $host = null;
106: 
107: /**
108:  * Session timeout multiplier factor
109:  *
110:  * @var int
111:  */
112:     public static $timeout = null;
113: 
114: /**
115:  * Number of requests that can occur during a session time without the session being renewed.
116:  * This feature is only used when config value `Session.autoRegenerate` is set to true.
117:  *
118:  * @var int
119:  * @see CakeSession::_checkValid()
120:  */
121:     public static $requestCountdown = 10;
122: 
123: /**
124:  * Whether or not the init function in this class was already called
125:  *
126:  * @var bool
127:  */
128:     protected static $_initialized = false;
129: 
130: /**
131:  * Session cookie name
132:  *
133:  * @var string
134:  */
135:     protected static $_cookieName = null;
136: 
137: /**
138:  * Pseudo constructor.
139:  *
140:  * @param string|null $base The base path for the Session
141:  * @return void
142:  */
143:     public static function init($base = null) {
144:         static::$time = time();
145: 
146:         if (env('HTTP_USER_AGENT')) {
147:             static::$_userAgent = md5(env('HTTP_USER_AGENT') . Configure::read('Security.salt'));
148:         }
149: 
150:         static::_setPath($base);
151:         static::_setHost(env('HTTP_HOST'));
152: 
153:         if (!static::$_initialized) {
154:             register_shutdown_function('session_write_close');
155:         }
156: 
157:         static::$_initialized = true;
158:     }
159: 
160: /**
161:  * Setup the Path variable
162:  *
163:  * @param string|null $base base path
164:  * @return void
165:  */
166:     protected static function _setPath($base = null) {
167:         if (empty($base)) {
168:             static::$path = '/';
169:             return;
170:         }
171:         if (strpos($base, 'index.php') !== false) {
172:             $base = str_replace('index.php', '', $base);
173:         }
174:         if (strpos($base, '?') !== false) {
175:             $base = str_replace('?', '', $base);
176:         }
177:         static::$path = $base;
178:     }
179: 
180: /**
181:  * Set the host name
182:  *
183:  * @param string $host Hostname
184:  * @return void
185:  */
186:     protected static function _setHost($host) {
187:         static::$host = $host;
188:         if (strpos(static::$host, ':') !== false) {
189:             static::$host = substr(static::$host, 0, strpos(static::$host, ':'));
190:         }
191:     }
192: 
193: /**
194:  * Starts the Session.
195:  *
196:  * @return bool True if session was started
197:  */
198:     public static function start() {
199:         if (static::started()) {
200:             return true;
201:         }
202: 
203:         $id = static::id();
204:         static::_startSession();
205: 
206:         if (!$id && static::started()) {
207:             static::_checkValid();
208:         }
209: 
210:         static::$error = false;
211:         static::$valid = true;
212:         return static::started();
213:     }
214: 
215: /**
216:  * Determine if Session has been started.
217:  *
218:  * @return bool True if session has been started.
219:  */
220:     public static function started() {
221:         return isset($_SESSION) && session_id();
222:     }
223: 
224: /**
225:  * Returns true if given variable is set in session.
226:  *
227:  * @param string $name Variable name to check for
228:  * @return bool True if variable is there
229:  */
230:     public static function check($name) {
231:         if (empty($name) || !static::_hasSession() || !static::start()) {
232:             return false;
233:         }
234: 
235:         return Hash::get($_SESSION, $name) !== null;
236:     }
237: 
238: /**
239:  * Returns the session id.
240:  * Calling this method will not auto start the session. You might have to manually
241:  * assert a started session.
242:  *
243:  * Passing an id into it, you can also replace the session id if the session
244:  * has not already been started.
245:  * Note that depending on the session handler, not all characters are allowed
246:  * within the session id. For example, the file session handler only allows
247:  * characters in the range a-z A-Z 0-9 , (comma) and - (minus).
248:  *
249:  * @param string|null $id Id to replace the current session id
250:  * @return string Session id
251:  */
252:     public static function id($id = null) {
253:         if ($id) {
254:             static::$id = $id;
255:             session_id(static::$id);
256:         }
257:         if (static::started()) {
258:             return session_id();
259:         }
260:         return static::$id;
261:     }
262: 
263: /**
264:  * Removes a variable from session.
265:  *
266:  * @param string $name Session variable to remove
267:  * @return bool Success
268:  */
269:     public static function delete($name) {
270:         if (static::check($name)) {
271:             static::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
272:             return !static::check($name);
273:         }
274:         return false;
275:     }
276: 
277: /**
278:  * Used to write new data to _SESSION, since PHP doesn't like us setting the _SESSION var itself.
279:  *
280:  * @param array &$old Set of old variables => values
281:  * @param array $new New set of variable => value
282:  * @return void
283:  */
284:     protected static function _overwrite(&$old, $new) {
285:         if (!empty($old)) {
286:             foreach ($old as $key => $var) {
287:                 if (!isset($new[$key])) {
288:                     unset($old[$key]);
289:                 }
290:             }
291:         }
292:         foreach ($new as $key => $var) {
293:             $old[$key] = $var;
294:         }
295:     }
296: 
297: /**
298:  * Return error description for given error number.
299:  *
300:  * @param int $errorNumber Error to set
301:  * @return string Error as string
302:  */
303:     protected static function _error($errorNumber) {
304:         if (!is_array(static::$error) || !array_key_exists($errorNumber, static::$error)) {
305:             return false;
306:         }
307:         return static::$error[$errorNumber];
308:     }
309: 
310: /**
311:  * Returns last occurred error as a string, if any.
312:  *
313:  * @return mixed Error description as a string, or false.
314:  */
315:     public static function error() {
316:         if (static::$lastError) {
317:             return static::_error(static::$lastError);
318:         }
319:         return false;
320:     }
321: 
322: /**
323:  * Returns true if session is valid.
324:  *
325:  * @return bool Success
326:  */
327:     public static function valid() {
328:         if (static::start() && static::read('Config')) {
329:             if (static::_validAgentAndTime() && static::$error === false) {
330:                 static::$valid = true;
331:             } else {
332:                 static::$valid = false;
333:                 static::_setError(1, 'Session Highjacking Attempted !!!');
334:             }
335:         }
336:         return static::$valid;
337:     }
338: 
339: /**
340:  * Tests that the user agent is valid and that the session hasn't 'timed out'.
341:  * Since timeouts are implemented in CakeSession it checks the current static::$time
342:  * against the time the session is set to expire. The User agent is only checked
343:  * if Session.checkAgent == true.
344:  *
345:  * @return bool
346:  */
347:     protected static function _validAgentAndTime() {
348:         $config = static::read('Config');
349:         $validAgent = (
350:             Configure::read('Session.checkAgent') === false ||
351:             isset($config['userAgent']) && static::$_userAgent === $config['userAgent']
352:         );
353:         return ($validAgent && static::$time <= $config['time']);
354:     }
355: 
356: /**
357:  * Get / Set the user agent
358:  *
359:  * @param string|null $userAgent Set the user agent
360:  * @return string Current user agent.
361:  */
362:     public static function userAgent($userAgent = null) {
363:         if ($userAgent) {
364:             static::$_userAgent = $userAgent;
365:         }
366:         if (empty(static::$_userAgent)) {
367:             CakeSession::init(static::$path);
368:         }
369:         return static::$_userAgent;
370:     }
371: 
372: /**
373:  * Returns given session variable, or all of them, if no parameters given.
374:  *
375:  * @param string|null $name The name of the session variable (or a path as sent to Set.extract)
376:  * @return mixed The value of the session variable, null if session not available,
377:  *   session not started, or provided name not found in the session, false on failure.
378:  */
379:     public static function read($name = null) {
380:         if (empty($name) && $name !== null) {
381:             return null;
382:         }
383:         if (!static::_hasSession() || !static::start()) {
384:             return null;
385:         }
386:         if ($name === null) {
387:             return static::_returnSessionVars();
388:         }
389:         $result = Hash::get($_SESSION, $name);
390: 
391:         if (isset($result)) {
392:             return $result;
393:         }
394:         return null;
395:     }
396: 
397: /**
398:  * Returns all session variables.
399:  *
400:  * @return mixed Full $_SESSION array, or false on error.
401:  */
402:     protected static function _returnSessionVars() {
403:         if (!empty($_SESSION)) {
404:             return $_SESSION;
405:         }
406:         static::_setError(2, 'No Session vars set');
407:         return false;
408:     }
409: 
410: /**
411:  * Writes value to given session variable name.
412:  *
413:  * @param string|array $name Name of variable
414:  * @param string $value Value to write
415:  * @return bool True if the write was successful, false if the write failed
416:  */
417:     public static function write($name, $value = null) {
418:         if (empty($name) || !static::start()) {
419:             return false;
420:         }
421: 
422:         $write = $name;
423:         if (!is_array($name)) {
424:             $write = array($name => $value);
425:         }
426:         foreach ($write as $key => $val) {
427:             static::_overwrite($_SESSION, Hash::insert($_SESSION, $key, $val));
428:             if (Hash::get($_SESSION, $key) !== $val) {
429:                 return false;
430:             }
431:         }
432:         return true;
433:     }
434: 
435: /**
436:  * Reads and deletes a variable from session.
437:  *
438:  * @param string $name The key to read and remove (or a path as sent to Hash.extract).
439:  * @return mixed The value of the session variable, null if session not available,
440:  *   session not started, or provided name not found in the session.
441:  */
442:     public static function consume($name) {
443:         if (empty($name)) {
444:             return null;
445:         }
446:         $value = static::read($name);
447:         if ($value !== null) {
448:             static::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
449:         }
450:         return $value;
451:     }
452: 
453: /**
454:  * Helper method to destroy invalid sessions.
455:  *
456:  * @return void
457:  */
458:     public static function destroy() {
459:         if (!static::started()) {
460:             static::_startSession();
461:         }
462: 
463:         if (static::started()) {
464:             session_destroy();
465:         }
466: 
467:         $_SESSION = null;
468:         static::$id = null;
469:         static::$_cookieName = null;
470:     }
471: 
472: /**
473:  * Clears the session.
474:  *
475:  * Optionally also clears the session id and renews the session.
476:  *
477:  * @param bool $renew If the session should also be renewed. Defaults to true.
478:  * @return void
479:  */
480:     public static function clear($renew = true) {
481:         if (!$renew) {
482:             $_SESSION = array();
483:             return;
484:         }
485: 
486:         $_SESSION = null;
487:         static::$id = null;
488:         static::renew();
489:     }
490: 
491: /**
492:  * Helper method to initialize a session, based on CakePHP core settings.
493:  *
494:  * Sessions can be configured with a few shortcut names as well as have any number of ini settings declared.
495:  *
496:  * @return void
497:  * @throws CakeSessionException Throws exceptions when ini_set() fails.
498:  */
499:     protected static function _configureSession() {
500:         $sessionConfig = Configure::read('Session');
501: 
502:         if (isset($sessionConfig['defaults'])) {
503:             $defaults = static::_defaultConfig($sessionConfig['defaults']);
504:             if ($defaults) {
505:                 $sessionConfig = Hash::merge($defaults, $sessionConfig);
506:             }
507:         }
508:         if (!isset($sessionConfig['ini']['session.cookie_secure']) && env('HTTPS')) {
509:             $sessionConfig['ini']['session.cookie_secure'] = 1;
510:         }
511:         if (isset($sessionConfig['timeout']) && !isset($sessionConfig['cookieTimeout'])) {
512:             $sessionConfig['cookieTimeout'] = $sessionConfig['timeout'];
513:         }
514:         if (!isset($sessionConfig['ini']['session.cookie_lifetime'])) {
515:             $sessionConfig['ini']['session.cookie_lifetime'] = $sessionConfig['cookieTimeout'] * 60;
516:         }
517: 
518:         if (!isset($sessionConfig['ini']['session.name'])) {
519:             $sessionConfig['ini']['session.name'] = $sessionConfig['cookie'];
520:         }
521:         static::$_cookieName = $sessionConfig['ini']['session.name'];
522: 
523:         if (!empty($sessionConfig['handler'])) {
524:             $sessionConfig['ini']['session.save_handler'] = 'user';
525:         } elseif (!empty($sessionConfig['session.save_path']) && Configure::read('debug')) {
526:             if (!is_dir($sessionConfig['session.save_path'])) {
527:                 mkdir($sessionConfig['session.save_path'], 0775, true);
528:             }
529:         }
530: 
531:         if (!isset($sessionConfig['ini']['session.gc_maxlifetime'])) {
532:             $sessionConfig['ini']['session.gc_maxlifetime'] = $sessionConfig['timeout'] * 60;
533:         }
534:         if (!isset($sessionConfig['ini']['session.cookie_httponly'])) {
535:             $sessionConfig['ini']['session.cookie_httponly'] = 1;
536:         }
537: 
538:         if (empty($_SESSION)) {
539:             if (!empty($sessionConfig['ini']) && is_array($sessionConfig['ini'])) {
540:                 foreach ($sessionConfig['ini'] as $setting => $value) {
541:                     if (ini_set($setting, $value) === false) {
542:                         throw new CakeSessionException(__d('cake_dev', 'Unable to configure the session, setting %s failed.', $setting));
543:                     }
544:                 }
545:             }
546:         }
547:         if (!empty($sessionConfig['handler']) && !isset($sessionConfig['handler']['engine'])) {
548:             call_user_func_array('session_set_save_handler', $sessionConfig['handler']);
549:         }
550:         if (!empty($sessionConfig['handler']['engine'])) {
551:             $handler = static::_getHandler($sessionConfig['handler']['engine']);
552:             session_set_save_handler(
553:                 array($handler, 'open'),
554:                 array($handler, 'close'),
555:                 array($handler, 'read'),
556:                 array($handler, 'write'),
557:                 array($handler, 'destroy'),
558:                 array($handler, 'gc')
559:             );
560:         }
561:         Configure::write('Session', $sessionConfig);
562:         static::$sessionTime = static::$time + ($sessionConfig['timeout'] * 60);
563:     }
564: 
565: /**
566:  * Get session cookie name.
567:  *
568:  * @return string
569:  */
570:     protected static function _cookieName() {
571:         if (static::$_cookieName !== null) {
572:             return static::$_cookieName;
573:         }
574: 
575:         static::init();
576:         static::_configureSession();
577: 
578:         return static::$_cookieName = session_name();
579:     }
580: 
581: /**
582:  * Returns whether a session exists
583:  *
584:  * @return bool
585:  */
586:     protected static function _hasSession() {
587:         return static::started() || isset($_COOKIE[static::_cookieName()]);
588:     }
589: 
590: /**
591:  * Find the handler class and make sure it implements the correct interface.
592:  *
593:  * @param string $handler Handler name.
594:  * @return void
595:  * @throws CakeSessionException
596:  */
597:     protected static function _getHandler($handler) {
598:         list($plugin, $class) = pluginSplit($handler, true);
599:         App::uses($class, $plugin . 'Model/Datasource/Session');
600:         if (!class_exists($class)) {
601:             throw new CakeSessionException(__d('cake_dev', 'Could not load %s to handle the session.', $class));
602:         }
603:         $handler = new $class();
604:         if ($handler instanceof CakeSessionHandlerInterface) {
605:             return $handler;
606:         }
607:         throw new CakeSessionException(__d('cake_dev', 'Chosen SessionHandler does not implement CakeSessionHandlerInterface it cannot be used with an engine key.'));
608:     }
609: 
610: /**
611:  * Get one of the prebaked default session configurations.
612:  *
613:  * @param string $name Config name.
614:  * @return bool|array
615:  */
616:     protected static function _defaultConfig($name) {
617:         $defaults = array(
618:             'php' => array(
619:                 'cookie' => 'CAKEPHP',
620:                 'timeout' => 240,
621:                 'ini' => array(
622:                     'session.use_trans_sid' => 0,
623:                     'session.cookie_path' => static::$path
624:                 )
625:             ),
626:             'cake' => array(
627:                 'cookie' => 'CAKEPHP',
628:                 'timeout' => 240,
629:                 'ini' => array(
630:                     'session.use_trans_sid' => 0,
631:                     'url_rewriter.tags' => '',
632:                     'session.serialize_handler' => 'php',
633:                     'session.use_cookies' => 1,
634:                     'session.cookie_path' => static::$path,
635:                     'session.save_path' => TMP . 'sessions',
636:                     'session.save_handler' => 'files'
637:                 )
638:             ),
639:             'cache' => array(
640:                 'cookie' => 'CAKEPHP',
641:                 'timeout' => 240,
642:                 'ini' => array(
643:                     'session.use_trans_sid' => 0,
644:                     'url_rewriter.tags' => '',
645:                     'session.use_cookies' => 1,
646:                     'session.cookie_path' => static::$path,
647:                     'session.save_handler' => 'user',
648:                 ),
649:                 'handler' => array(
650:                     'engine' => 'CacheSession',
651:                     'config' => 'default'
652:                 )
653:             ),
654:             'database' => array(
655:                 'cookie' => 'CAKEPHP',
656:                 'timeout' => 240,
657:                 'ini' => array(
658:                     'session.use_trans_sid' => 0,
659:                     'url_rewriter.tags' => '',
660:                     'session.use_cookies' => 1,
661:                     'session.cookie_path' => static::$path,
662:                     'session.save_handler' => 'user',
663:                     'session.serialize_handler' => 'php',
664:                 ),
665:                 'handler' => array(
666:                     'engine' => 'DatabaseSession',
667:                     'model' => 'Session'
668:                 )
669:             )
670:         );
671:         if (isset($defaults[$name])) {
672:             return $defaults[$name];
673:         }
674:         return false;
675:     }
676: 
677: /**
678:  * Helper method to start a session
679:  *
680:  * @return bool Success
681:  */
682:     protected static function _startSession() {
683:         static::init();
684:         session_write_close();
685:         static::_configureSession();
686: 
687:         if (headers_sent()) {
688:             if (empty($_SESSION)) {
689:                 $_SESSION = array();
690:             }
691:         } else {
692:             // For IE<=8
693:             session_cache_limiter("must-revalidate");
694:             session_start();
695:         }
696:         return true;
697:     }
698: 
699: /**
700:  * Helper method to create a new session.
701:  *
702:  * @return void
703:  */
704:     protected static function _checkValid() {
705:         $config = static::read('Config');
706:         if ($config) {
707:             $sessionConfig = Configure::read('Session');
708: 
709:             if (static::valid()) {
710:                 static::write('Config.time', static::$sessionTime);
711:                 if (isset($sessionConfig['autoRegenerate']) && $sessionConfig['autoRegenerate'] === true) {
712:                     $check = $config['countdown'];
713:                     $check -= 1;
714:                     static::write('Config.countdown', $check);
715: 
716:                     if ($check < 1) {
717:                         static::renew();
718:                         static::write('Config.countdown', static::$requestCountdown);
719:                     }
720:                 }
721:             } else {
722:                 $_SESSION = array();
723:                 static::destroy();
724:                 static::_setError(1, 'Session Highjacking Attempted !!!');
725:                 static::_startSession();
726:                 static::_writeConfig();
727:             }
728:         } else {
729:             static::_writeConfig();
730:         }
731:     }
732: 
733: /**
734:  * Writes configuration variables to the session
735:  *
736:  * @return void
737:  */
738:     protected static function _writeConfig() {
739:         static::write('Config.userAgent', static::$_userAgent);
740:         static::write('Config.time', static::$sessionTime);
741:         static::write('Config.countdown', static::$requestCountdown);
742:     }
743: 
744: /**
745:  * Restarts this session.
746:  *
747:  * @return void
748:  */
749:     public static function renew() {
750:         if (session_id() === '') {
751:             return;
752:         }
753:         if (isset($_COOKIE[session_name()])) {
754:             setcookie(Configure::read('Session.cookie'), '', time() - 42000, static::$path);
755:         }
756:         session_regenerate_id(true);
757:     }
758: 
759: /**
760:  * Helper method to set an internal error message.
761:  *
762:  * @param int $errorNumber Number of the error
763:  * @param string $errorMessage Description of the error
764:  * @return void
765:  */
766:     protected static function _setError($errorNumber, $errorMessage) {
767:         if (static::$error === false) {
768:             static::$error = array();
769:         }
770:         static::$error[$errorNumber] = $errorMessage;
771:         static::$lastError = $errorNumber;
772:     }
773: 
774: }
775: