X-Git-Url: https://scripts.mit.edu/gitweb/autoinstallsdev/mediawiki.git/blobdiff_plain/19e297c21b10b1b8a3acad5e73fc71dcb35db44a..6932310fd58ebef145fa01eb76edf7150284d8ea:/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();
+	}
+}