]> scripts.mit.edu Git - autoinstallsdev/mediawiki.git/blobdiff - includes/session/PHPSessionHandler.php
MediaWiki 1.30.2
[autoinstallsdev/mediawiki.git] / includes / session / PHPSessionHandler.php
diff --git a/includes/session/PHPSessionHandler.php b/includes/session/PHPSessionHandler.php
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+<?php
+/**
+ * Session storage in object cache.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Session
+ */
+
+namespace MediaWiki\Session;
+
+use Psr\Log\LoggerInterface;
+use BagOStuff;
+
+/**
+ * Adapter for PHP's session handling
+ * @ingroup Session
+ * @since 1.27
+ */
+class PHPSessionHandler implements \SessionHandlerInterface {
+       /** @var PHPSessionHandler */
+       protected static $instance = null;
+
+       /** @var bool Whether PHP session handling is enabled */
+       protected $enable = false;
+       protected $warn = true;
+
+       /** @var SessionManager|null */
+       protected $manager;
+
+       /** @var BagOStuff|null */
+       protected $store;
+
+       /** @var LoggerInterface */
+       protected $logger;
+
+       /** @var array Track original session fields for later modification check */
+       protected $sessionFieldCache = [];
+
+       protected function __construct( SessionManager $manager ) {
+               $this->setEnableFlags(
+                       \RequestContext::getMain()->getConfig()->get( 'PHPSessionHandling' )
+               );
+               $manager->setupPHPSessionHandler( $this );
+       }
+
+       /**
+        * Set $this->enable and $this->warn
+        *
+        * Separate just because there doesn't seem to be a good way to test it
+        * otherwise.
+        *
+        * @param string $PHPSessionHandling See $wgPHPSessionHandling
+        */
+       private function setEnableFlags( $PHPSessionHandling ) {
+               switch ( $PHPSessionHandling ) {
+                       case 'enable':
+                               $this->enable = true;
+                               $this->warn = false;
+                               break;
+
+                       case 'warn':
+                               $this->enable = true;
+                               $this->warn = true;
+                               break;
+
+                       case 'disable':
+                               $this->enable = false;
+                               $this->warn = false;
+                               break;
+               }
+       }
+
+       /**
+        * Test whether the handler is installed
+        * @return bool
+        */
+       public static function isInstalled() {
+               return (bool)self::$instance;
+       }
+
+       /**
+        * Test whether the handler is installed and enabled
+        * @return bool
+        */
+       public static function isEnabled() {
+               return self::$instance && self::$instance->enable;
+       }
+
+       /**
+        * Install a session handler for the current web request
+        * @param SessionManager $manager
+        */
+       public static function install( SessionManager $manager ) {
+               if ( self::$instance ) {
+                       $manager->setupPHPSessionHandler( self::$instance );
+                       return;
+               }
+
+               // @codeCoverageIgnoreStart
+               if ( defined( 'MW_NO_SESSION_HANDLER' ) ) {
+                       throw new \BadMethodCallException( 'MW_NO_SESSION_HANDLER is defined' );
+               }
+               // @codeCoverageIgnoreEnd
+
+               self::$instance = new self( $manager );
+
+               // Close any auto-started session, before we replace it
+               session_write_close();
+
+               // Tell PHP not to mess with cookies itself
+               ini_set( 'session.use_cookies', 0 );
+               ini_set( 'session.use_trans_sid', 0 );
+
+               // T124510: Disable automatic PHP session related cache headers.
+               // MediaWiki adds it's own headers and the default PHP behavior may
+               // set headers such as 'Pragma: no-cache' that cause problems with
+               // some user agents.
+               session_cache_limiter( '' );
+
+               // Also set a sane serialization handler
+               \Wikimedia\PhpSessionSerializer::setSerializeHandler();
+
+               // Register this as the save handler, and register an appropriate
+               // shutdown function.
+               session_set_save_handler( self::$instance, true );
+       }
+
+       /**
+        * Set the manager, store, and logger
+        * @private Use self::install().
+        * @param SessionManager $manager
+        * @param BagOStuff $store
+        * @param LoggerInterface $logger
+        */
+       public function setManager(
+               SessionManager $manager, BagOStuff $store, LoggerInterface $logger
+       ) {
+               if ( $this->manager !== $manager ) {
+                       // Close any existing session before we change stores
+                       if ( $this->manager ) {
+                               session_write_close();
+                       }
+                       $this->manager = $manager;
+                       $this->store = $store;
+                       $this->logger = $logger;
+                       \Wikimedia\PhpSessionSerializer::setLogger( $this->logger );
+               }
+       }
+
+       /**
+        * Workaround for PHP5 bug
+        *
+        * PHP5 has a bug in handling boolean return values for
+        * SessionHandlerInterface methods, it expects 0 or -1 instead of true or
+        * false. See <https://wiki.php.net/rfc/session.user.return-value>.
+        *
+        * PHP7 and HHVM are not affected.
+        *
+        * @todo When we drop support for Zend PHP 5, this can be removed.
+        * @return bool|int
+        * @codeCoverageIgnore
+        */
+       protected static function returnSuccess() {
+               return defined( 'HHVM_VERSION' ) || version_compare( PHP_VERSION, '7.0.0', '>=' ) ? true : 0;
+       }
+
+       /**
+        * Workaround for PHP5 bug
+        * @see self::returnSuccess()
+        * @return bool|int
+        * @codeCoverageIgnore
+        */
+       protected static function returnFailure() {
+               return defined( 'HHVM_VERSION' ) || version_compare( PHP_VERSION, '7.0.0', '>=' ) ? false : -1;
+       }
+
+       /**
+        * Initialize the session (handler)
+        * @private For internal use only
+        * @param string $save_path Path used to store session files (ignored)
+        * @param string $session_name Session name (ignored)
+        * @return bool|int Success (see self::returnSuccess())
+        */
+       public function open( $save_path, $session_name ) {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               if ( !$this->enable ) {
+                       throw new \BadMethodCallException( 'Attempt to use PHP session management' );
+               }
+               return self::returnSuccess();
+       }
+
+       /**
+        * Close the session (handler)
+        * @private For internal use only
+        * @return bool|int Success (see self::returnSuccess())
+        */
+       public function close() {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               $this->sessionFieldCache = [];
+               return self::returnSuccess();
+       }
+
+       /**
+        * Read session data
+        * @private For internal use only
+        * @param string $id Session id
+        * @return string Session data
+        */
+       public function read( $id ) {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               if ( !$this->enable ) {
+                       throw new \BadMethodCallException( 'Attempt to use PHP session management' );
+               }
+
+               $session = $this->manager->getSessionById( $id, false );
+               if ( !$session ) {
+                       return '';
+               }
+               $session->persist();
+
+               $data = iterator_to_array( $session );
+               $this->sessionFieldCache[$id] = $data;
+               return (string)\Wikimedia\PhpSessionSerializer::encode( $data );
+       }
+
+       /**
+        * Write session data
+        * @private For internal use only
+        * @param string $id Session id
+        * @param string $dataStr Session data. Not that you should ever call this
+        *   directly, but note that this has the same issues with code injection
+        *   via user-controlled data as does PHP's unserialize function.
+        * @return bool|int Success (see self::returnSuccess())
+        */
+       public function write( $id, $dataStr ) {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               if ( !$this->enable ) {
+                       throw new \BadMethodCallException( 'Attempt to use PHP session management' );
+               }
+
+               $session = $this->manager->getSessionById( $id, true );
+               if ( !$session ) {
+                       // This can happen under normal circumstances, if the session exists but is
+                       // invalid. Let's emit a log warning instead of a PHP warning.
+                       $this->logger->warning(
+                               __METHOD__ . ': Session "{session}" cannot be loaded, skipping write.',
+                               [
+                                       'session' => $id,
+                       ] );
+                       return self::returnSuccess();
+               }
+
+               // First, decode the string PHP handed us
+               $data = \Wikimedia\PhpSessionSerializer::decode( $dataStr );
+               if ( $data === null ) {
+                       // @codeCoverageIgnoreStart
+                       return self::returnFailure();
+                       // @codeCoverageIgnoreEnd
+               }
+
+               // Now merge the data into the Session object.
+               $changed = false;
+               $cache = isset( $this->sessionFieldCache[$id] ) ? $this->sessionFieldCache[$id] : [];
+               foreach ( $data as $key => $value ) {
+                       if ( !array_key_exists( $key, $cache ) ) {
+                               if ( $session->exists( $key ) ) {
+                                       // New in both, so ignore and log
+                                       $this->logger->warning(
+                                               __METHOD__ . ": Key \"$key\" added in both Session and \$_SESSION!"
+                                       );
+                               } else {
+                                       // New in $_SESSION, keep it
+                                       $session->set( $key, $value );
+                                       $changed = true;
+                               }
+                       } elseif ( $cache[$key] === $value ) {
+                               // Unchanged in $_SESSION, so ignore it
+                       } elseif ( !$session->exists( $key ) ) {
+                               // Deleted in Session, keep but log
+                               $this->logger->warning(
+                                       __METHOD__ . ": Key \"$key\" deleted in Session and changed in \$_SESSION!"
+                               );
+                               $session->set( $key, $value );
+                               $changed = true;
+                       } elseif ( $cache[$key] === $session->get( $key ) ) {
+                               // Unchanged in Session, so keep it
+                               $session->set( $key, $value );
+                               $changed = true;
+                       } else {
+                               // Changed in both, so ignore and log
+                               $this->logger->warning(
+                                       __METHOD__ . ": Key \"$key\" changed in both Session and \$_SESSION!"
+                               );
+                       }
+               }
+               // Anything deleted in $_SESSION and unchanged in Session should be deleted too
+               // (but not if $_SESSION can't represent it at all)
+               \Wikimedia\PhpSessionSerializer::setLogger( new \Psr\Log\NullLogger() );
+               foreach ( $cache as $key => $value ) {
+                       if ( !array_key_exists( $key, $data ) && $session->exists( $key ) &&
+                               \Wikimedia\PhpSessionSerializer::encode( [ $key => true ] )
+                       ) {
+                               if ( $cache[$key] === $session->get( $key ) ) {
+                                       // Unchanged in Session, delete it
+                                       $session->remove( $key );
+                                       $changed = true;
+                               } else {
+                                       // Changed in Session, ignore deletion and log
+                                       $this->logger->warning(
+                                               __METHOD__ . ": Key \"$key\" changed in Session and deleted in \$_SESSION!"
+                                       );
+                               }
+                       }
+               }
+               \Wikimedia\PhpSessionSerializer::setLogger( $this->logger );
+
+               // Save and update cache if anything changed
+               if ( $changed ) {
+                       if ( $this->warn ) {
+                               wfDeprecated( '$_SESSION', '1.27' );
+                               $this->logger->warning( 'Something wrote to $_SESSION!' );
+                       }
+
+                       $session->save();
+                       $this->sessionFieldCache[$id] = iterator_to_array( $session );
+               }
+
+               $session->persist();
+
+               return self::returnSuccess();
+       }
+
+       /**
+        * Destroy a session
+        * @private For internal use only
+        * @param string $id Session id
+        * @return bool|int Success (see self::returnSuccess())
+        */
+       public function destroy( $id ) {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               if ( !$this->enable ) {
+                       throw new \BadMethodCallException( 'Attempt to use PHP session management' );
+               }
+               $session = $this->manager->getSessionById( $id, false );
+               if ( $session ) {
+                       $session->clear();
+               }
+               return self::returnSuccess();
+       }
+
+       /**
+        * Execute garbage collection.
+        * @private For internal use only
+        * @param int $maxlifetime Maximum session life time (ignored)
+        * @return bool|int Success (see self::returnSuccess())
+        * @codeCoverageIgnore See T135576
+        */
+       public function gc( $maxlifetime ) {
+               if ( self::$instance !== $this ) {
+                       throw new \UnexpectedValueException( __METHOD__ . ': Wrong instance called!' );
+               }
+               $before = date( 'YmdHis', time() );
+               $this->store->deleteObjectsExpiringBefore( $before );
+               return self::returnSuccess();
+       }
+}