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::$time = time();
145: 
146:         if (env('HTTP_USER_AGENT') && !static::$_userAgent) {
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:         $id = static::id();
204:         static::_startSession();
205:         if (!$id && static::started()) {
206:             static::_checkValid();
207:         }
208: 
209:         static::$error = false;
210:         static::$valid = true;
211:         return static::started();
212:     }
213: 
214: /**
215:  * Determine if Session has been started.
216:  *
217:  * @return bool True if session has been started.
218:  */
219:     public static function started() {
220:         if (function_exists('session_status')) {
221:             return isset($_SESSION) && (session_status() === PHP_SESSION_ACTIVE);
222:         }
223:         return isset($_SESSION) && session_id();
224:     }
225: 
226: /**
227:  * Returns true if given variable is set in session.
228:  *
229:  * @param string $name Variable name to check for
230:  * @return bool True if variable is there
231:  */
232:     public static function check($name) {
233:         if (empty($name) || !static::_hasSession() || !static::start()) {
234:             return false;
235:         }
236: 
237:         return Hash::get($_SESSION, $name) !== null;
238:     }
239: 
240: /**
241:  * Returns the session id.
242:  * Calling this method will not auto start the session. You might have to manually
243:  * assert a started session.
244:  *
245:  * Passing an id into it, you can also replace the session id if the session
246:  * has not already been started.
247:  * Note that depending on the session handler, not all characters are allowed
248:  * within the session id. For example, the file session handler only allows
249:  * characters in the range a-z A-Z 0-9 , (comma) and - (minus).
250:  *
251:  * @param string|null $id Id to replace the current session id
252:  * @return string Session id
253:  */
254:     public static function id($id = null) {
255:         if ($id) {
256:             static::$id = $id;
257:             session_id(static::$id);
258:         }
259:         if (static::started()) {
260:             return session_id();
261:         }
262:         return static::$id;
263:     }
264: 
265: /**
266:  * Removes a variable from session.
267:  *
268:  * @param string $name Session variable to remove
269:  * @return bool Success
270:  */
271:     public static function delete($name) {
272:         if (static::check($name)) {
273:             static::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
274:             return !static::check($name);
275:         }
276:         return false;
277:     }
278: 
279: /**
280:  * Used to write new data to _SESSION, since PHP doesn't like us setting the _SESSION var itself.
281:  *
282:  * @param array &$old Set of old variables => values
283:  * @param array $new New set of variable => value
284:  * @return void
285:  */
286:     protected static function _overwrite(&$old, $new) {
287:         if (!empty($old)) {
288:             foreach ($old as $key => $var) {
289:                 if (!isset($new[$key])) {
290:                     unset($old[$key]);
291:                 }
292:             }
293:         }
294:         foreach ($new as $key => $var) {
295:             $old[$key] = $var;
296:         }
297:     }
298: 
299: /**
300:  * Return error description for given error number.
301:  *
302:  * @param int $errorNumber Error to set
303:  * @return string Error as string
304:  */
305:     protected static function _error($errorNumber) {
306:         if (!is_array(static::$error) || !array_key_exists($errorNumber, static::$error)) {
307:             return false;
308:         }
309:         return static::$error[$errorNumber];
310:     }
311: 
312: /**
313:  * Returns last occurred error as a string, if any.
314:  *
315:  * @return mixed Error description as a string, or false.
316:  */
317:     public static function error() {
318:         if (static::$lastError) {
319:             return static::_error(static::$lastError);
320:         }
321:         return false;
322:     }
323: 
324: /**
325:  * Returns true if session is valid.
326:  *
327:  * @return bool Success
328:  */
329:     public static function valid() {
330:         if (static::start() && static::read('Config')) {
331:             if (static::_validAgentAndTime() && static::$error === false) {
332:                 static::$valid = true;
333:             } else {
334:                 static::$valid = false;
335:                 static::_setError(1, 'Session Highjacking Attempted !!!');
336:             }
337:         }
338:         return static::$valid;
339:     }
340: 
341: /**
342:  * Tests that the user agent is valid and that the session hasn't 'timed out'.
343:  * Since timeouts are implemented in CakeSession it checks the current static::$time
344:  * against the time the session is set to expire. The User agent is only checked
345:  * if Session.checkAgent == true.
346:  *
347:  * @return bool
348:  */
349:     protected static function _validAgentAndTime() {
350:         $userAgent = static::read('Config.userAgent');
351:         $time = static::read('Config.time');
352:         $validAgent = (
353:             Configure::read('Session.checkAgent') === false ||
354:             isset($userAgent) && static::$_userAgent === $userAgent
355:         );
356:         return ($validAgent && static::$time <= $time);
357:     }
358: 
359: /**
360:  * Get / Set the user agent
361:  *
362:  * @param string|null $userAgent Set the user agent
363:  * @return string Current user agent.
364:  */
365:     public static function userAgent($userAgent = null) {
366:         if ($userAgent) {
367:             static::$_userAgent = $userAgent;
368:         }
369:         if (empty(static::$_userAgent)) {
370:             CakeSession::init(static::$path);
371:         }
372:         return static::$_userAgent;
373:     }
374: 
375: /**
376:  * Returns given session variable, or all of them, if no parameters given.
377:  *
378:  * @param string|null $name The name of the session variable (or a path as sent to Set.extract)
379:  * @return mixed The value of the session variable, null if session not available,
380:  *   session not started, or provided name not found in the session, false on failure.
381:  */
382:     public static function read($name = null) {
383:         if (empty($name) && $name !== null) {
384:             return null;
385:         }
386:         if (!static::_hasSession() || !static::start()) {
387:             return null;
388:         }
389:         if ($name === null) {
390:             return static::_returnSessionVars();
391:         }
392:         $result = Hash::get($_SESSION, $name);
393: 
394:         if (isset($result)) {
395:             return $result;
396:         }
397:         return null;
398:     }
399: 
400: /**
401:  * Returns all session variables.
402:  *
403:  * @return mixed Full $_SESSION array, or false on error.
404:  */
405:     protected static function _returnSessionVars() {
406:         if (!empty($_SESSION)) {
407:             return $_SESSION;
408:         }
409:         static::_setError(2, 'No Session vars set');
410:         return false;
411:     }
412: 
413: /**
414:  * Writes value to given session variable name.
415:  *
416:  * @param string|array $name Name of variable
417:  * @param string $value Value to write
418:  * @return bool True if the write was successful, false if the write failed
419:  */
420:     public static function write($name, $value = null) {
421:         if (empty($name) || !static::start()) {
422:             return false;
423:         }
424: 
425:         $write = $name;
426:         if (!is_array($name)) {
427:             $write = array($name => $value);
428:         }
429:         foreach ($write as $key => $val) {
430:             static::_overwrite($_SESSION, Hash::insert($_SESSION, $key, $val));
431:             if (Hash::get($_SESSION, $key) !== $val) {
432:                 return false;
433:             }
434:         }
435:         return true;
436:     }
437: 
438: /**
439:  * Reads and deletes a variable from session.
440:  *
441:  * @param string $name The key to read and remove (or a path as sent to Hash.extract).
442:  * @return mixed The value of the session variable, null if session not available,
443:  *   session not started, or provided name not found in the session.
444:  */
445:     public static function consume($name) {
446:         if (empty($name)) {
447:             return null;
448:         }
449:         $value = static::read($name);
450:         if ($value !== null) {
451:             static::_overwrite($_SESSION, Hash::remove($_SESSION, $name));
452:         }
453:         return $value;
454:     }
455: 
456: /**
457:  * Helper method to destroy invalid sessions.
458:  *
459:  * @return void
460:  */
461:     public static function destroy() {
462:         if (!static::started()) {
463:             static::_startSession();
464:         }
465: 
466:         if (static::started()) {
467:             if (session_id() && static::_hasSession()) {
468:                 session_write_close();
469:                 session_start();
470:             }
471:             session_destroy();
472:             unset($_COOKIE[static::_cookieName()]);
473:         }
474: 
475:         $_SESSION = null;
476:         static::$id = null;
477:         static::$_cookieName = null;
478:     }
479: 
480: /**
481:  * Clears the session.
482:  *
483:  * Optionally also clears the session id and renews the session.
484:  *
485:  * @param bool $renew If the session should also be renewed. Defaults to true.
486:  * @return void
487:  */
488:     public static function clear($renew = true) {
489:         if (!$renew) {
490:             $_SESSION = array();
491:             return;
492:         }
493: 
494:         $_SESSION = null;
495:         static::$id = null;
496:         static::renew();
497:     }
498: 
499: /**
500:  * Helper method to initialize a session, based on CakePHP core settings.
501:  *
502:  * Sessions can be configured with a few shortcut names as well as have any number of ini settings declared.
503:  *
504:  * @return void
505:  * @throws CakeSessionException Throws exceptions when ini_set() fails.
506:  */
507:     protected static function _configureSession() {
508:         $sessionConfig = Configure::read('Session');
509: 
510:         if (isset($sessionConfig['defaults'])) {
511:             $defaults = static::_defaultConfig($sessionConfig['defaults']);
512:             if ($defaults) {
513:                 $sessionConfig = Hash::merge($defaults, $sessionConfig);
514:             }
515:         }
516:         if (!isset($sessionConfig['ini']['session.cookie_secure']) && env('HTTPS')) {
517:             $sessionConfig['ini']['session.cookie_secure'] = 1;
518:         }
519:         if (isset($sessionConfig['timeout']) && !isset($sessionConfig['cookieTimeout'])) {
520:             $sessionConfig['cookieTimeout'] = $sessionConfig['timeout'];
521:         }
522:         if (!isset($sessionConfig['ini']['session.cookie_lifetime'])) {
523:             $sessionConfig['ini']['session.cookie_lifetime'] = $sessionConfig['cookieTimeout'] * 60;
524:         }
525: 
526:         if (!isset($sessionConfig['ini']['session.name'])) {
527:             $sessionConfig['ini']['session.name'] = $sessionConfig['cookie'];
528:         }
529:         static::$_cookieName = $sessionConfig['ini']['session.name'];
530: 
531:         if (!empty($sessionConfig['handler'])) {
532:             $sessionConfig['ini']['session.save_handler'] = 'user';
533:         } elseif (!empty($sessionConfig['session.save_path']) && Configure::read('debug')) {
534:             if (!is_dir($sessionConfig['session.save_path'])) {
535:                 mkdir($sessionConfig['session.save_path'], 0775, true);
536:             }
537:         }
538: 
539:         if (!isset($sessionConfig['ini']['session.gc_maxlifetime'])) {
540:             $sessionConfig['ini']['session.gc_maxlifetime'] = $sessionConfig['timeout'] * 60;
541:         }
542:         if (!isset($sessionConfig['ini']['session.cookie_httponly'])) {
543:             $sessionConfig['ini']['session.cookie_httponly'] = 1;
544:         }
545:         // For IE<=8
546:         if (!isset($sessionConfig['cacheLimiter'])) {
547:             $sessionConfig['cacheLimiter'] = 'must-revalidate';
548:         }
549: 
550:         if (empty($_SESSION)) {
551:             if (!empty($sessionConfig['ini']) && is_array($sessionConfig['ini'])) {
552:                 foreach ($sessionConfig['ini'] as $setting => $value) {
553:                     if (ini_set($setting, $value) === false) {
554:                         throw new CakeSessionException(__d('cake_dev', 'Unable to configure the session, setting %s failed.', $setting));
555:                     }
556:                 }
557:             }
558:         }
559:         if (!empty($sessionConfig['handler']) && !isset($sessionConfig['handler']['engine'])) {
560:             call_user_func_array('session_set_save_handler', $sessionConfig['handler']);
561:         }
562:         if (!empty($sessionConfig['handler']['engine'])) {
563:             $handler = static::_getHandler($sessionConfig['handler']['engine']);
564:             session_set_save_handler(
565:                 array($handler, 'open'),
566:                 array($handler, 'close'),
567:                 array($handler, 'read'),
568:                 array($handler, 'write'),
569:                 array($handler, 'destroy'),
570:                 array($handler, 'gc')
571:             );
572:         }
573:         Configure::write('Session', $sessionConfig);
574:         static::$sessionTime = static::$time + ($sessionConfig['timeout'] * 60);
575:     }
576: 
577: /**
578:  * Get session cookie name.
579:  *
580:  * @return string
581:  */
582:     protected static function _cookieName() {
583:         if (static::$_cookieName !== null) {
584:             return static::$_cookieName;
585:         }
586: 
587:         static::init();
588:         static::_configureSession();
589: 
590:         return static::$_cookieName = session_name();
591:     }
592: 
593: /**
594:  * Returns whether a session exists
595:  *
596:  * @return bool
597:  */
598:     protected static function _hasSession() {
599:         return static::started() || isset($_COOKIE[static::_cookieName()]) || (PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg');
600:     }
601: 
602: /**
603:  * Find the handler class and make sure it implements the correct interface.
604:  *
605:  * @param string $handler Handler name.
606:  * @return void
607:  * @throws CakeSessionException
608:  */
609:     protected static function _getHandler($handler) {
610:         list($plugin, $class) = pluginSplit($handler, true);
611:         App::uses($class, $plugin . 'Model/Datasource/Session');
612:         if (!class_exists($class)) {
613:             throw new CakeSessionException(__d('cake_dev', 'Could not load %s to handle the session.', $class));
614:         }
615:         $handler = new $class();
616:         if ($handler instanceof CakeSessionHandlerInterface) {
617:             return $handler;
618:         }
619:         throw new CakeSessionException(__d('cake_dev', 'Chosen SessionHandler does not implement CakeSessionHandlerInterface it cannot be used with an engine key.'));
620:     }
621: 
622: /**
623:  * Get one of the prebaked default session configurations.
624:  *
625:  * @param string $name Config name.
626:  * @return bool|array
627:  */
628:     protected static function _defaultConfig($name) {
629:         $defaults = array(
630:             'php' => array(
631:                 'cookie' => 'CAKEPHP',
632:                 'timeout' => 240,
633:                 'ini' => array(
634:                     'session.use_trans_sid' => 0,
635:                     'session.cookie_path' => static::$path
636:                 )
637:             ),
638:             'cake' => array(
639:                 'cookie' => 'CAKEPHP',
640:                 'timeout' => 240,
641:                 'ini' => array(
642:                     'session.use_trans_sid' => 0,
643:                     'url_rewriter.tags' => '',
644:                     'session.serialize_handler' => 'php',
645:                     'session.use_cookies' => 1,
646:                     'session.cookie_path' => static::$path,
647:                     'session.save_path' => TMP . 'sessions',
648:                     'session.save_handler' => 'files'
649:                 )
650:             ),
651:             'cache' => array(
652:                 'cookie' => 'CAKEPHP',
653:                 'timeout' => 240,
654:                 'ini' => array(
655:                     'session.use_trans_sid' => 0,
656:                     'url_rewriter.tags' => '',
657:                     'session.use_cookies' => 1,
658:                     'session.cookie_path' => static::$path,
659:                     'session.save_handler' => 'user',
660:                 ),
661:                 'handler' => array(
662:                     'engine' => 'CacheSession',
663:                     'config' => 'default'
664:                 )
665:             ),
666:             'database' => array(
667:                 'cookie' => 'CAKEPHP',
668:                 'timeout' => 240,
669:                 'ini' => array(
670:                     'session.use_trans_sid' => 0,
671:                     'url_rewriter.tags' => '',
672:                     'session.use_cookies' => 1,
673:                     'session.cookie_path' => static::$path,
674:                     'session.save_handler' => 'user',
675:                     'session.serialize_handler' => 'php',
676:                 ),
677:                 'handler' => array(
678:                     'engine' => 'DatabaseSession',
679:                     'model' => 'Session'
680:                 )
681:             )
682:         );
683:         if (isset($defaults[$name])) {
684:             return $defaults[$name];
685:         }
686:         return false;
687:     }
688: 
689: /**
690:  * Helper method to start a session
691:  *
692:  * @return bool Success
693:  */
694:     protected static function _startSession() {
695:         static::init();
696:         session_write_close();
697:         static::_configureSession();
698: 
699:         if (headers_sent()) {
700:             if (empty($_SESSION)) {
701:                 $_SESSION = array();
702:             }
703:         } else {
704:             $limit = Configure::read('Session.cacheLimiter');
705:             if (!empty($limit)) {
706:                 session_cache_limiter($limit);
707:             }
708:             session_start();
709:         }
710:         return true;
711:     }
712: 
713: /**
714:  * Helper method to create a new session.
715:  *
716:  * @return void
717:  */
718:     protected static function _checkValid() {
719:         $config = static::read('Config');
720:         if ($config) {
721:             $sessionConfig = Configure::read('Session');
722: 
723:             if (static::valid()) {
724:                 static::write('Config.time', static::$sessionTime);
725:                 if (isset($sessionConfig['autoRegenerate']) && $sessionConfig['autoRegenerate'] === true) {
726:                     $check = $config['countdown'];
727:                     $check -= 1;
728:                     static::write('Config.countdown', $check);
729: 
730:                     if ($check < 1) {
731:                         static::renew();
732:                         static::write('Config.countdown', static::$requestCountdown);
733:                     }
734:                 }
735:             } else {
736:                 $_SESSION = array();
737:                 static::destroy();
738:                 static::_setError(1, 'Session Highjacking Attempted !!!');
739:                 static::_startSession();
740:                 static::_writeConfig();
741:             }
742:         } else {
743:             static::_writeConfig();
744:         }
745:     }
746: 
747: /**
748:  * Writes configuration variables to the session
749:  *
750:  * @return void
751:  */
752:     protected static function _writeConfig() {
753:         static::write('Config.userAgent', static::$_userAgent);
754:         static::write('Config.time', static::$sessionTime);
755:         static::write('Config.countdown', static::$requestCountdown);
756:     }
757: 
758: /**
759:  * Restarts this session.
760:  *
761:  * @return void
762:  */
763:     public static function renew() {
764:         if (session_id() === '') {
765:             return;
766:         }
767:         if (isset($_COOKIE[static::_cookieName()])) {
768:             setcookie(Configure::read('Session.cookie'), '', time() - 42000, static::$path);
769:         }
770:         if (!headers_sent()) {
771:             session_write_close();
772:             session_start();
773:             session_regenerate_id(true);
774:         }
775:     }
776: 
777: /**
778:  * Helper method to set an internal error message.
779:  *
780:  * @param int $errorNumber Number of the error
781:  * @param string $errorMessage Description of the error
782:  * @return void
783:  */
784:     protected static function _setError($errorNumber, $errorMessage) {
785:         if (static::$error === false) {
786:             static::$error = array();
787:         }
788:         static::$error[$errorNumber] = $errorMessage;
789:         static::$lastError = $errorNumber;
790:     }
791: 
792: }
793: