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 $base The base path for the Session
141:  * @return void
142:  */
143:     public static function init($base = null) {
144:         self::$time = time();
145: 
146:         if (env('HTTP_USER_AGENT')) {
147:             self::$_userAgent = md5(env('HTTP_USER_AGENT') . Configure::read('Security.salt'));
148:         }
149: 
150:         self::_setPath($base);
151:         self::_setHost(env('HTTP_HOST'));
152: 
153:         if (!self::$_initialized) {
154:             register_shutdown_function('session_write_close');
155:         }
156: 
157:         self::$_initialized = true;
158:     }
159: 
160: /**
161:  * Setup the Path variable
162:  *
163:  * @param string $base base path
164:  * @return void
165:  */
166:     protected static function _setPath($base = null) {
167:         if (empty($base)) {
168:             self::$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('?', '', $base);
176:         }
177:         self::$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:         self::$host = $host;
188:         if (strpos(self::$host, ':') !== false) {
189:             self::$host = substr(self::$host, 0, strpos(self::$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 (self::started()) {
200:             return true;
201:         }
202: 
203:         $id = self::id();
204:         self::_startSession();
205: 
206:         if (!$id && self::started()) {
207:             self::_checkValid();
208:         }
209: 
210:         self::$error = false;
211:         self::$valid = true;
212:         return self::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 = null) {
231:         if (empty($name) || !self::_hasSession() || !self::start()) {
232:             return false;
233:         }
234: 
235:         return Hash::get($_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 $id Id to replace the current session id
250:  * @return string Session id
251:  */
252:     public static function id($id = null) {
253:         if ($id) {
254:             self::$id = $id;
255:             session_id(self::$id);
256:         }
257:         if (self::started()) {
258:             return session_id();
259:         }
260:         return self::$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 (self::check($name)) {
271:             self::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
272:             return !self::check($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(self::$error) || !array_key_exists($errorNumber, self::$error)) {
305:             return false;
306:         }
307:         return self::$error[$errorNumber];
308:     }
309: 
310: /**
311:  * Returns last occurred error as a string, if any.
312:  *
313:  * @return mixed Error description as a string, or false.
314:  */
315:     public static function error() {
316:         if (self::$lastError) {
317:             return self::_error(self::$lastError);
318:         }
319:         return false;
320:     }
321: 
322: /**
323:  * Returns true if session is valid.
324:  *
325:  * @return bool Success
326:  */
327:     public static function valid() {
328:         if (self::start() && self::read('Config')) {
329:             if (self::_validAgentAndTime() && self::$error === false) {
330:                 self::$valid = true;
331:             } else {
332:                 self::$valid = false;
333:                 self::_setError(1, 'Session Highjacking Attempted !!!');
334:             }
335:         }
336:         return self::$valid;
337:     }
338: 
339: /**
340:  * Tests that the user agent is valid and that the session hasn't 'timed out'.
341:  * Since timeouts are implemented in CakeSession it checks the current self::$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 = self::read('Config');
349:         $validAgent = (
350:             Configure::read('Session.checkAgent') === false ||
351:             isset($config['userAgent']) && self::$_userAgent === $config['userAgent']
352:         );
353:         return ($validAgent && self::$time <= $config['time']);
354:     }
355: 
356: /**
357:  * Get / Set the user agent
358:  *
359:  * @param string $userAgent Set the user agent
360:  * @return string Current user agent
361:  */
362:     public static function userAgent($userAgent = null) {
363:         if ($userAgent) {
364:             self::$_userAgent = $userAgent;
365:         }
366:         if (empty(self::$_userAgent)) {
367:             CakeSession::init(self::$path);
368:         }
369:         return self::$_userAgent;
370:     }
371: 
372: /**
373:  * Returns given session variable, or all of them, if no parameters given.
374:  *
375:  * @param string|array $name The name of the session variable (or a path as sent to Set.extract)
376:  * @return mixed The value of the session variable, null if session not available,
377:  *   session not started, or provided name not found in the session.
378:  */
379:     public static function read($name = null) {
380:         if (empty($name) && $name !== null) {
381:             return null;
382:         }
383:         if (!self::_hasSession() || !self::start()) {
384:             return null;
385:         }
386:         if ($name === null) {
387:             return self::_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:         self::_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) || !self::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 => $val) {
427:             self::_overwrite($_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:  * Helper method to destroy invalid sessions.
437:  *
438:  * @return void
439:  */
440:     public static function destroy() {
441:         if (!self::started()) {
442:             self::_startSession();
443:         }
444: 
445:         session_destroy();
446: 
447:         $_SESSION = null;
448:         self::$id = null;
449:         self::$_cookieName = null;
450:     }
451: 
452: /**
453:  * Clears the session, the session id, and renews the session.
454:  *
455:  * @return void
456:  */
457:     public static function clear() {
458:         $_SESSION = null;
459:         self::$id = null;
460:         self::renew();
461:     }
462: 
463: /**
464:  * Helper method to initialize a session, based on CakePHP core settings.
465:  *
466:  * Sessions can be configured with a few shortcut names as well as have any number of ini settings declared.
467:  *
468:  * @return void
469:  * @throws CakeSessionException Throws exceptions when ini_set() fails.
470:  */
471:     protected static function _configureSession() {
472:         $sessionConfig = Configure::read('Session');
473: 
474:         if (isset($sessionConfig['defaults'])) {
475:             $defaults = self::_defaultConfig($sessionConfig['defaults']);
476:             if ($defaults) {
477:                 $sessionConfig = Hash::merge($defaults, $sessionConfig);
478:             }
479:         }
480:         if (!isset($sessionConfig['ini']['session.cookie_secure']) && env('HTTPS')) {
481:             $sessionConfig['ini']['session.cookie_secure'] = 1;
482:         }
483:         if (isset($sessionConfig['timeout']) && !isset($sessionConfig['cookieTimeout'])) {
484:             $sessionConfig['cookieTimeout'] = $sessionConfig['timeout'];
485:         }
486:         if (!isset($sessionConfig['ini']['session.cookie_lifetime'])) {
487:             $sessionConfig['ini']['session.cookie_lifetime'] = $sessionConfig['cookieTimeout'] * 60;
488:         }
489: 
490:         if (!isset($sessionConfig['ini']['session.name'])) {
491:             $sessionConfig['ini']['session.name'] = $sessionConfig['cookie'];
492:         }
493:         self::$_cookieName = $sessionConfig['ini']['session.name'];
494: 
495:         if (!empty($sessionConfig['handler'])) {
496:             $sessionConfig['ini']['session.save_handler'] = 'user';
497:         }
498:         if (!isset($sessionConfig['ini']['session.gc_maxlifetime'])) {
499:             $sessionConfig['ini']['session.gc_maxlifetime'] = $sessionConfig['timeout'] * 60;
500:         }
501:         if (!isset($sessionConfig['ini']['session.cookie_httponly'])) {
502:             $sessionConfig['ini']['session.cookie_httponly'] = 1;
503:         }
504: 
505:         if (empty($_SESSION)) {
506:             if (!empty($sessionConfig['ini']) && is_array($sessionConfig['ini'])) {
507:                 foreach ($sessionConfig['ini'] as $setting => $value) {
508:                     if (ini_set($setting, $value) === false) {
509:                         throw new CakeSessionException(__d('cake_dev', 'Unable to configure the session, setting %s failed.', $setting));
510:                     }
511:                 }
512:             }
513:         }
514:         if (!empty($sessionConfig['handler']) && !isset($sessionConfig['handler']['engine'])) {
515:             call_user_func_array('session_set_save_handler', $sessionConfig['handler']);
516:         }
517:         if (!empty($sessionConfig['handler']['engine'])) {
518:             $handler = self::_getHandler($sessionConfig['handler']['engine']);
519:             session_set_save_handler(
520:                 array($handler, 'open'),
521:                 array($handler, 'close'),
522:                 array($handler, 'read'),
523:                 array($handler, 'write'),
524:                 array($handler, 'destroy'),
525:                 array($handler, 'gc')
526:             );
527:         }
528:         Configure::write('Session', $sessionConfig);
529:         self::$sessionTime = self::$time + ($sessionConfig['timeout'] * 60);
530:     }
531: 
532: /**
533:  * Get session cookie name.
534:  *
535:  * @return string
536:  */
537:     protected static function _cookieName() {
538:         if (self::$_cookieName !== null) {
539:             return self::$_cookieName;
540:         }
541: 
542:         self::init();
543:         self::_configureSession();
544: 
545:         return self::$_cookieName = session_name();
546:     }
547: 
548: /**
549:  * Returns whether a session exists
550:  *
551:  * @return bool
552:  */
553:     protected static function _hasSession() {
554:         return self::started() || isset($_COOKIE[self::_cookieName()]);
555:     }
556: 
557: /**
558:  * Find the handler class and make sure it implements the correct interface.
559:  *
560:  * @param string $handler Handler name.
561:  * @return void
562:  * @throws CakeSessionException
563:  */
564:     protected static function _getHandler($handler) {
565:         list($plugin, $class) = pluginSplit($handler, true);
566:         App::uses($class, $plugin . 'Model/Datasource/Session');
567:         if (!class_exists($class)) {
568:             throw new CakeSessionException(__d('cake_dev', 'Could not load %s to handle the session.', $class));
569:         }
570:         $handler = new $class();
571:         if ($handler instanceof CakeSessionHandlerInterface) {
572:             return $handler;
573:         }
574:         throw new CakeSessionException(__d('cake_dev', 'Chosen SessionHandler does not implement CakeSessionHandlerInterface it cannot be used with an engine key.'));
575:     }
576: 
577: /**
578:  * Get one of the prebaked default session configurations.
579:  *
580:  * @param string $name Config name.
581:  * @return bool|array
582:  */
583:     protected static function _defaultConfig($name) {
584:         $defaults = array(
585:             'php' => array(
586:                 'cookie' => 'CAKEPHP',
587:                 'timeout' => 240,
588:                 'ini' => array(
589:                     'session.use_trans_sid' => 0,
590:                     'session.cookie_path' => self::$path
591:                 )
592:             ),
593:             'cake' => array(
594:                 'cookie' => 'CAKEPHP',
595:                 'timeout' => 240,
596:                 'ini' => array(
597:                     'session.use_trans_sid' => 0,
598:                     'url_rewriter.tags' => '',
599:                     'session.serialize_handler' => 'php',
600:                     'session.use_cookies' => 1,
601:                     'session.cookie_path' => self::$path,
602:                     'session.save_path' => TMP . 'sessions',
603:                     'session.save_handler' => 'files'
604:                 )
605:             ),
606:             'cache' => array(
607:                 'cookie' => 'CAKEPHP',
608:                 'timeout' => 240,
609:                 'ini' => array(
610:                     'session.use_trans_sid' => 0,
611:                     'url_rewriter.tags' => '',
612:                     'session.use_cookies' => 1,
613:                     'session.cookie_path' => self::$path,
614:                     'session.save_handler' => 'user',
615:                 ),
616:                 'handler' => array(
617:                     'engine' => 'CacheSession',
618:                     'config' => 'default'
619:                 )
620:             ),
621:             'database' => array(
622:                 'cookie' => 'CAKEPHP',
623:                 'timeout' => 240,
624:                 'ini' => array(
625:                     'session.use_trans_sid' => 0,
626:                     'url_rewriter.tags' => '',
627:                     'session.use_cookies' => 1,
628:                     'session.cookie_path' => self::$path,
629:                     'session.save_handler' => 'user',
630:                     'session.serialize_handler' => 'php',
631:                 ),
632:                 'handler' => array(
633:                     'engine' => 'DatabaseSession',
634:                     'model' => 'Session'
635:                 )
636:             )
637:         );
638:         if (isset($defaults[$name])) {
639:             return $defaults[$name];
640:         }
641:         return false;
642:     }
643: 
644: /**
645:  * Helper method to start a session
646:  *
647:  * @return bool Success
648:  */
649:     protected static function _startSession() {
650:         self::init();
651:         session_write_close();
652:         self::_configureSession();
653: 
654:         if (headers_sent()) {
655:             if (empty($_SESSION)) {
656:                 $_SESSION = array();
657:             }
658:         } else {
659:             // For IE<=8
660:             session_cache_limiter("must-revalidate");
661:             session_start();
662:         }
663:         return true;
664:     }
665: 
666: /**
667:  * Helper method to create a new session.
668:  *
669:  * @return void
670:  */
671:     protected static function _checkValid() {
672:         $config = self::read('Config');
673:         if ($config) {
674:             $sessionConfig = Configure::read('Session');
675: 
676:             if (self::valid()) {
677:                 self::write('Config.time', self::$sessionTime);
678:                 if (isset($sessionConfig['autoRegenerate']) && $sessionConfig['autoRegenerate'] === true) {
679:                     $check = $config['countdown'];
680:                     $check -= 1;
681:                     self::write('Config.countdown', $check);
682: 
683:                     if ($check < 1) {
684:                         self::renew();
685:                         self::write('Config.countdown', self::$requestCountdown);
686:                     }
687:                 }
688:             } else {
689:                 $_SESSION = array();
690:                 self::destroy();
691:                 self::_setError(1, 'Session Highjacking Attempted !!!');
692:                 self::_startSession();
693:                 self::_writeConfig();
694:             }
695:         } else {
696:             self::_writeConfig();
697:         }
698:     }
699: 
700: /**
701:  * Writes configuration variables to the session
702:  *
703:  * @return void
704:  */
705:     protected static function _writeConfig() {
706:         self::write('Config.userAgent', self::$_userAgent);
707:         self::write('Config.time', self::$sessionTime);
708:         self::write('Config.countdown', self::$requestCountdown);
709:     }
710: 
711: /**
712:  * Restarts this session.
713:  *
714:  * @return void
715:  */
716:     public static function renew() {
717:         if (!session_id()) {
718:             return;
719:         }
720:         if (isset($_COOKIE[session_name()])) {
721:             setcookie(Configure::read('Session.cookie'), '', time() - 42000, self::$path);
722:         }
723:         session_regenerate_id(true);
724:     }
725: 
726: /**
727:  * Helper method to set an internal error message.
728:  *
729:  * @param int $errorNumber Number of the error
730:  * @param string $errorMessage Description of the error
731:  * @return void
732:  */
733:     protected static function _setError($errorNumber, $errorMessage) {
734:         if (self::$error === false) {
735:             self::$error = array();
736:         }
737:         self::$error[$errorNumber] = $errorMessage;
738:         self::$lastError = $errorNumber;
739:     }
740: 
741: }
742: