Merge "docs: Fix typo"

[mediawiki.git] / includes / session / SessionManager.php

<?php
/**
 * MediaWiki\Session entry point
 *
 * 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 InvalidArgumentException;
use LogicException;
use MediaWiki\Config\Config;
use MediaWiki\Context\RequestContext;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Request\FauxRequest;
use MediaWiki\Request\WebRequest;
use MediaWiki\User\User;
use MediaWiki\User\UserNameUtils;
use MWException;
use Psr\Log\LoggerInterface;
use Psr\Log\LogLevel;
use Wikimedia\ObjectCache\BagOStuff;
use Wikimedia\ObjectCache\CachedBagOStuff;

/**
 * This serves as the entry point to the MediaWiki session handling system.
 *
 * Most methods here are for internal use by session handling code. Other callers
 * should only use getGlobalSession and the methods of SessionManagerInterface;
 * the rest of the functionality is exposed via MediaWiki\Session\Session methods.
 *
 * To provide custom session handling, implement a MediaWiki\Session\SessionProvider.
 *
 * @anchor SessionManager-storage-expectations
 *
 * ## Storage expectations
 *
 * The SessionManager should be configured with a very fast storage system that is
 * optimized for holding key-value pairs. It expects:
 *
 * - Low latencies. Session data is read or written to during nearly all web requests from
 *   people that have contributed to or otherwise engaged with the site, including those not
 *   logged in with a registered account.
 *
 * - Locally writable data. The data must be writable from both primary and secondary
 *   data centres.
 *
 * - Locally latest reads. Writes must by default be immediately consistent within
 *   the local data centre, and visible to other reads from web servers in that data centre.
 *
 * - Replication. The data must be eventually consistent across all data centres. Writes
 *   are either synced to all remote data centres, or locally overwritten by another write
 *   that is.
 *
 * The SessionManager uses `set()` and `delete()` for write operations, which should be
 * synchronous in the local data centre, and replicate asynchronously to any others.
 *
 * @ingroup Session
 * @since 1.27
 * @see https://www.mediawiki.org/wiki/Manual:SessionManager_and_AuthManager
 */
class SessionManager implements SessionManagerInterface {
        private static ?SessionManager $instance = null;
        private static ?Session $globalSession = null;
        private static ?WebRequest $globalSessionRequest = null;

        private LoggerInterface $logger;
        private HookContainer $hookContainer;
        private HookRunner $hookRunner;
        private Config $config;
        private UserNameUtils $userNameUtils;
        private CachedBagOStuff $store;

        /** @var SessionProvider[] */
        private $sessionProviders = null;

        /** @var string[] */
        private $varyCookies = null;

        /** @var array */
        private $varyHeaders = null;

        /** @var SessionBackend[] */
        private $allSessionBackends = [];

        /** @var SessionId[] */
        private $allSessionIds = [];

        /** @var true[] */
        private $preventUsers = [];

        /**
         * Get the global SessionManager
         * @return self
         */
        public static function singleton() {
                if ( self::$instance === null ) {
                        self::$instance = new self();
                }
                return self::$instance;
        }

        /**
         * If PHP's session_id() has been set, returns that session. Otherwise
         * returns the session for RequestContext::getMain()->getRequest().
         */
        public static function getGlobalSession(): Session {
                if ( !PHPSessionHandler::isEnabled() ) {
                        $id = '';
                } else {
                        $id = session_id();
                }

                $request = RequestContext::getMain()->getRequest();
                if (
                        !self::$globalSession // No global session is set up yet
                        || self::$globalSessionRequest !== $request // The global WebRequest changed
                        || ( $id !== '' && self::$globalSession->getId() !== $id ) // Someone messed with session_id()
                ) {
                        self::$globalSessionRequest = $request;
                        if ( $id === '' ) {
                                // session_id() wasn't used, so fetch the Session from the WebRequest.
                                // We use $request->getSession() instead of $singleton->getSessionForRequest()
                                // because doing the latter would require a public
                                // "$request->getSessionId()" method that would confuse end
                                // users by returning SessionId|null where they'd expect it to
                                // be short for $request->getSession()->getId(), and would
                                // wind up being a duplicate of the code in
                                // $request->getSession() anyway.
                                self::$globalSession = $request->getSession();
                        } else {
                                // Someone used session_id(), so we need to follow suit.
                                // Note this overwrites whatever session might already be
                                // associated with $request with the one for $id.
                                self::$globalSession = self::singleton()->getSessionById( $id, true, $request )
                                        ?: $request->getSession();
                        }
                }
                return self::$globalSession;
        }

        /**
         * @param array $options
         *  - config: Config to fetch configuration from. Defaults to the default 'main' config.
         *  - logger: LoggerInterface to use for logging. Defaults to the 'session' channel.
         *  - store: BagOStuff to store session data in.
         */
        public function __construct( $options = [] ) {
                $services = MediaWikiServices::getInstance();

                $this->config = $options['config'] ?? $services->getMainConfig();
                $this->setLogger( $options['logger'] ?? \MediaWiki\Logger\LoggerFactory::getInstance( 'session' ) );
                $this->setHookContainer( $options['hookContainer'] ?? $services->getHookContainer() );

                $store = $options['store'] ?? $services->getObjectCacheFactory()
                        ->getInstance( $this->config->get( MainConfigNames::SessionCacheType ) );
                $this->logger->debug( 'SessionManager using store ' . get_class( $store ) );
                $this->store = $store instanceof CachedBagOStuff ? $store : new CachedBagOStuff( $store );

                $this->userNameUtils = $services->getUserNameUtils();

                register_shutdown_function( [ $this, 'shutdown' ] );
        }

        public function setLogger( LoggerInterface $logger ) {
                $this->logger = $logger;
        }

        /**
         * @internal
         * @param HookContainer $hookContainer
         */
        public function setHookContainer( HookContainer $hookContainer ) {
                $this->hookContainer = $hookContainer;
                $this->hookRunner = new HookRunner( $hookContainer );
        }

        public function getSessionForRequest( WebRequest $request ) {
                $info = $this->getSessionInfoForRequest( $request );

                if ( !$info ) {
                        $session = $this->getInitialSession( $request );
                } else {
                        $session = $this->getSessionFromInfo( $info, $request );
                }
                return $session;
        }

        public function getSessionById( $id, $create = false, ?WebRequest $request = null ) {
                if ( !self::validateSessionId( $id ) ) {
                        throw new InvalidArgumentException( 'Invalid session ID' );
                }
                if ( !$request ) {
                        $request = new FauxRequest;
                }

                $session = null;
                $info = new SessionInfo( SessionInfo::MIN_PRIORITY, [ 'id' => $id, 'idIsSafe' => true ] );

                // If we already have the backend loaded, use it directly
                if ( isset( $this->allSessionBackends[$id] ) ) {
                        return $this->getSessionFromInfo( $info, $request );
                }

                // Test if the session is in storage, and if so try to load it.
                $key = $this->store->makeKey( 'MWSession', $id );
                if ( is_array( $this->store->get( $key ) ) ) {
                        $create = false; // If loading fails, don't bother creating because it probably will fail too.
                        if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
                                $session = $this->getSessionFromInfo( $info, $request );
                        }
                }

                if ( $create && $session === null ) {
                        try {
                                $session = $this->getEmptySessionInternal( $request, $id );
                        } catch ( \Exception $ex ) {
                                $this->logger->error( 'Failed to create empty session: {exception}',
                                        [
                                                'method' => __METHOD__,
                                                'exception' => $ex,
                                ] );
                                $session = null;
                        }
                }

                return $session;
        }

        public function getEmptySession( ?WebRequest $request = null ) {
                return $this->getEmptySessionInternal( $request );
        }

        /**
         * @see SessionManagerInterface::getEmptySession
         * @param WebRequest|null $request
         * @param string|null $id ID to force on the new session
         * @return Session
         */
        private function getEmptySessionInternal( ?WebRequest $request = null, $id = null ) {
                if ( $id !== null ) {
                        if ( !self::validateSessionId( $id ) ) {
                                throw new InvalidArgumentException( 'Invalid session ID' );
                        }

                        $key = $this->store->makeKey( 'MWSession', $id );
                        if ( is_array( $this->store->get( $key ) ) ) {
                                throw new InvalidArgumentException( 'Session ID already exists' );
                        }
                }
                if ( !$request ) {
                        $request = new FauxRequest;
                }

                $infos = [];
                foreach ( $this->getProviders() as $provider ) {
                        $info = $provider->newSessionInfo( $id );
                        if ( !$info ) {
                                continue;
                        }
                        if ( $info->getProvider() !== $provider ) {
                                throw new \UnexpectedValueException(
                                        "$provider returned an empty session info for a different provider: $info"
                                );
                        }
                        if ( $id !== null && $info->getId() !== $id ) {
                                throw new \UnexpectedValueException(
                                        "$provider returned empty session info with a wrong id: " .
                                                $info->getId() . ' != ' . $id
                                );
                        }
                        if ( !$info->isIdSafe() ) {
                                throw new \UnexpectedValueException(
                                        "$provider returned empty session info with id flagged unsafe"
                                );
                        }
                        $compare = $infos ? SessionInfo::compare( $infos[0], $info ) : -1;
                        if ( $compare > 0 ) {
                                continue;
                        }
                        if ( $compare === 0 ) {
                                $infos[] = $info;
                        } else {
                                $infos = [ $info ];
                        }
                }

                // Make sure there's exactly one
                if ( count( $infos ) > 1 ) {
                        throw new \UnexpectedValueException(
                                'Multiple empty sessions tied for top priority: ' . implode( ', ', $infos )
                        );
                } elseif ( count( $infos ) < 1 ) {
                        throw new \UnexpectedValueException( 'No provider could provide an empty session!' );
                }

                // @phan-suppress-next-line PhanTypePossiblyInvalidDimOffset False positive
                return $this->getSessionFromInfo( $infos[0], $request );
        }

        /**
         * Create a new session. Populate it with a default secret token, to avoid
         * a session replication race on a subsequent edit/save cycle (e.g. in
         * a multi-dc setup, ref https://phabricator.wikimedia.org/T279664#8139533).
         *
         * @param WebRequest|null $request Corresponding request. Any existing
         *  session associated with this WebRequest object will be overwritten.
         * @return Session
         */
        private function getInitialSession( ?WebRequest $request = null ) {
                $session = $this->getEmptySession( $request );
                $session->getToken();
                return $session;
        }

        public function invalidateSessionsForUser( User $user ) {
                $user->setToken();
                $user->saveSettings();

                foreach ( $this->getProviders() as $provider ) {
                        $provider->invalidateSessionsForUser( $user );
                }
        }

        /**
         * @return array<string,null>
         */
        public function getVaryHeaders() {
                // @codeCoverageIgnoreStart
                if ( defined( 'MW_NO_SESSION' ) && MW_NO_SESSION !== 'warn' ) {
                        return [];
                }
                // @codeCoverageIgnoreEnd
                if ( $this->varyHeaders === null ) {
                        $headers = [];
                        foreach ( $this->getProviders() as $provider ) {
                                foreach ( $provider->getVaryHeaders() as $header => $_ ) {
                                        $headers[$header] = null;
                                }
                        }
                        $this->varyHeaders = $headers;
                }
                return $this->varyHeaders;
        }

        public function getVaryCookies() {
                // @codeCoverageIgnoreStart
                if ( defined( 'MW_NO_SESSION' ) && MW_NO_SESSION !== 'warn' ) {
                        return [];
                }
                // @codeCoverageIgnoreEnd
                if ( $this->varyCookies === null ) {
                        $cookies = [];
                        foreach ( $this->getProviders() as $provider ) {
                                $cookies = array_merge( $cookies, $provider->getVaryCookies() );
                        }
                        $this->varyCookies = array_values( array_unique( $cookies ) );
                }
                return $this->varyCookies;
        }

        /**
         * Validate a session ID
         * @param string $id
         * @return bool
         */
        public static function validateSessionId( $id ) {
                return is_string( $id ) && preg_match( '/^[a-zA-Z0-9_-]{32,}$/', $id );
        }

        /***************************************************************************/
        // region   Internal methods
        /** @name   Internal methods */

        /**
         * Prevent future sessions for the user
         *
         * The intention is that the named account will never again be usable for
         * normal login (i.e. there is no way to undo the prevention of access).
         *
         * @internal For use from \MediaWiki\User\User::newSystemUser only
         * @param string $username
         */
        public function preventSessionsForUser( $username ) {
                $this->preventUsers[$username] = true;

                // Instruct the session providers to kill any other sessions too.
                foreach ( $this->getProviders() as $provider ) {
                        $provider->preventSessionsForUser( $username );
                }
        }

        /**
         * Test if a user is prevented
         * @internal For use from SessionBackend only
         * @param string $username
         * @return bool
         */
        public function isUserSessionPrevented( $username ) {
                return !empty( $this->preventUsers[$username] );
        }

        /**
         * Get the available SessionProviders
         * @return SessionProvider[]
         */
        protected function getProviders() {
                if ( $this->sessionProviders === null ) {
                        $this->sessionProviders = [];
                        $objectFactory = MediaWikiServices::getInstance()->getObjectFactory();
                        foreach ( $this->config->get( MainConfigNames::SessionProviders ) as $spec ) {
                                /** @var SessionProvider $provider */
                                $provider = $objectFactory->createObject( $spec );
                                $provider->init(
                                        $this->logger,
                                        $this->config,
                                        $this,
                                        $this->hookContainer,
                                        $this->userNameUtils
                                );
                                if ( isset( $this->sessionProviders[(string)$provider] ) ) {
                                        // @phan-suppress-next-line PhanTypeSuspiciousStringExpression
                                        throw new \UnexpectedValueException( "Duplicate provider name \"$provider\"" );
                                }
                                $this->sessionProviders[(string)$provider] = $provider;
                        }
                }
                return $this->sessionProviders;
        }

        /**
         * Get a session provider by name
         *
         * Generally, this will only be used by internal implementation of some
         * special session-providing mechanism. General purpose code, if it needs
         * to access a SessionProvider at all, will use Session::getProvider().
         *
         * @param string $name
         * @return SessionProvider|null
         */
        public function getProvider( $name ) {
                $providers = $this->getProviders();
                return $providers[$name] ?? null;
        }

        /**
         * Save all active sessions on shutdown
         * @internal For internal use with register_shutdown_function()
         */
        public function shutdown() {
                if ( $this->allSessionBackends ) {
                        $this->logger->debug( 'Saving all sessions on shutdown' );
                        if ( session_id() !== '' ) {
                                // @codeCoverageIgnoreStart
                                session_write_close();
                        }
                        // @codeCoverageIgnoreEnd
                        foreach ( $this->allSessionBackends as $backend ) {
                                $backend->shutdown();
                        }
                }
        }

        /**
         * Fetch the SessionInfo(s) for a request
         * @param WebRequest $request
         * @return SessionInfo|null
         */
        private function getSessionInfoForRequest( WebRequest $request ) {
                // Call all providers to fetch "the" session
                $infos = [];
                foreach ( $this->getProviders() as $provider ) {
                        $info = $provider->provideSessionInfo( $request );
                        if ( !$info ) {
                                continue;
                        }
                        if ( $info->getProvider() !== $provider ) {
                                throw new \UnexpectedValueException(
                                        "$provider returned session info for a different provider: $info"
                                );
                        }
                        $infos[] = $info;
                }

                // Sort the SessionInfos. Then find the first one that can be
                // successfully loaded, and then all the ones after it with the same
                // priority.
                usort( $infos, [ SessionInfo::class, 'compare' ] );
                $retInfos = [];
                while ( $infos ) {
                        $info = array_pop( $infos );
                        if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
                                $retInfos[] = $info;
                                while ( $infos ) {
                                        /** @var SessionInfo $info */
                                        $info = array_pop( $infos );
                                        if ( SessionInfo::compare( $retInfos[0], $info ) ) {
                                                // We hit a lower priority, stop checking.
                                                break;
                                        }
                                        if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
                                                // This is going to error out below, but we want to
                                                // provide a complete list.
                                                $retInfos[] = $info;
                                        } else {
                                                // Session load failed, so unpersist it from this request
                                                $this->logUnpersist( $info, $request );
                                                $info->getProvider()->unpersistSession( $request );
                                        }
                                }
                        } else {
                                // Session load failed, so unpersist it from this request
                                $this->logUnpersist( $info, $request );
                                $info->getProvider()->unpersistSession( $request );
                        }
                }

                if ( count( $retInfos ) > 1 ) {
                        throw new SessionOverflowException(
                                $retInfos,
                                'Multiple sessions for this request tied for top priority: ' . implode( ', ', $retInfos )
                        );
                }

                return $retInfos[0] ?? null;
        }

        /**
         * Load and verify the session info against the store
         *
         * @param SessionInfo &$info Will likely be replaced with an updated SessionInfo instance
         * @param WebRequest $request
         * @return bool Whether the session info matches the stored data (if any)
         */
        private function loadSessionInfoFromStore( SessionInfo &$info, WebRequest $request ) {
                $key = $this->store->makeKey( 'MWSession', $info->getId() );
                $blob = $this->store->get( $key );

                // If we got data from the store and the SessionInfo says to force use,
                // "fail" means to delete the data from the store and retry. Otherwise,
                // "fail" is just return false.
                if ( $info->forceUse() && $blob !== false ) {
                        $failHandler = function () use ( $key, &$info, $request ) {
                                $this->store->delete( $key );
                                return $this->loadSessionInfoFromStore( $info, $request );
                        };
                } else {
                        $failHandler = static function () {
                                return false;
                        };
                }

                $newParams = [];

                if ( $blob !== false ) {
                        // Double check: blob must be an array, if it's saved at all
                        if ( !is_array( $blob ) ) {
                                $this->logger->warning( 'Session "{session}": Bad data', [
                                        'session' => $info->__toString(),
                                ] );
                                $this->store->delete( $key );
                                return $failHandler();
                        }

                        // Double check: blob has data and metadata arrays
                        if ( !isset( $blob['data'] ) || !is_array( $blob['data'] ) ||
                                !isset( $blob['metadata'] ) || !is_array( $blob['metadata'] )
                        ) {
                                $this->logger->warning( 'Session "{session}": Bad data structure', [
                                        'session' => $info->__toString(),
                                ] );
                                $this->store->delete( $key );
                                return $failHandler();
                        }

                        $data = $blob['data'];
                        $metadata = $blob['metadata'];

                        // Double check: metadata must be an array and must contain certain
                        // keys, if it's saved at all
                        if ( !array_key_exists( 'userId', $metadata ) ||
                                !array_key_exists( 'userName', $metadata ) ||
                                !array_key_exists( 'userToken', $metadata ) ||
                                !array_key_exists( 'provider', $metadata )
                        ) {
                                $this->logger->warning( 'Session "{session}": Bad metadata', [
                                        'session' => $info->__toString(),
                                ] );
                                $this->store->delete( $key );
                                return $failHandler();
                        }

                        // First, load the provider from metadata, or validate it against the metadata.
                        $provider = $info->getProvider();
                        if ( $provider === null ) {
                                $newParams['provider'] = $provider = $this->getProvider( $metadata['provider'] );
                                if ( !$provider ) {
                                        $this->logger->warning(
                                                'Session "{session}": Unknown provider ' . $metadata['provider'],
                                                [
                                                        'session' => $info->__toString(),
                                                ]
                                        );
                                        $this->store->delete( $key );
                                        return $failHandler();
                                }
                        } elseif ( $metadata['provider'] !== (string)$provider ) {
                                $this->logger->warning( 'Session "{session}": Wrong provider ' .
                                        $metadata['provider'] . ' !== ' . $provider,
                                        [
                                                'session' => $info->__toString(),
                                ] );
                                return $failHandler();
                        }

                        // Load provider metadata from metadata, or validate it against the metadata
                        $providerMetadata = $info->getProviderMetadata();
                        if ( isset( $metadata['providerMetadata'] ) ) {
                                if ( $providerMetadata === null ) {
                                        $newParams['metadata'] = $metadata['providerMetadata'];
                                } else {
                                        try {
                                                $newProviderMetadata = $provider->mergeMetadata(
                                                        $metadata['providerMetadata'], $providerMetadata
                                                );
                                                if ( $newProviderMetadata !== $providerMetadata ) {
                                                        $newParams['metadata'] = $newProviderMetadata;
                                                }
                                        } catch ( MetadataMergeException $ex ) {
                                                $this->logger->warning(
                                                        'Session "{session}": Metadata merge failed: {exception}',
                                                        [
                                                                'session' => $info->__toString(),
                                                                'exception' => $ex,
                                                        ] + $ex->getContext()
                                                );
                                                return $failHandler();
                                        }
                                }
                        }

                        // Next, load the user from metadata, or validate it against the metadata.
                        $userInfo = $info->getUserInfo();
                        if ( !$userInfo ) {
                                // For loading, id is preferred to name.
                                try {
                                        if ( $metadata['userId'] ) {
                                                $userInfo = UserInfo::newFromId( $metadata['userId'] );
                                        } elseif ( $metadata['userName'] !== null ) { // Shouldn't happen, but just in case
                                                $userInfo = UserInfo::newFromName( $metadata['userName'] );
                                        } else {
                                                $userInfo = UserInfo::newAnonymous();
                                        }
                                } catch ( InvalidArgumentException $ex ) {
                                        $this->logger->error( 'Session "{session}": {exception}', [
                                                'session' => $info->__toString(),
                                                'exception' => $ex,
                                        ] );
                                        return $failHandler();
                                }
                                $newParams['userInfo'] = $userInfo;
                        } else {
                                // User validation passes if user ID matches, or if there
                                // is no saved ID and the names match.
                                if ( $metadata['userId'] ) {
                                        if ( $metadata['userId'] !== $userInfo->getId() ) {
                                                // Maybe something like UserMerge changed the user ID. Or it's manual tampering.
                                                $this->logger->warning(
                                                        'Session "{session}": User ID mismatch, {uid_a} !== {uid_b}',
                                                        [
                                                                'session' => $info->__toString(),
                                                                'uid_a' => $metadata['userId'],
                                                                'uid_b' => $userInfo->getId(),
                                                                'uname_a' => $metadata['userName'] ?? '<null>',
                                                                'uname_b' => $userInfo->getName() ?? '<null>',
                                                        ] );
                                                return $failHandler();
                                        }

                                        // If the user was renamed, probably best to fail here.
                                        if ( $metadata['userName'] !== null &&
                                                $userInfo->getName() !== $metadata['userName']
                                        ) {
                                                $this->logger->warning(
                                                        'Session "{session}": User ID matched but name didn\'t (rename?), {uname_a} !== {uname_b}',
                                                        [
                                                                'session' => $info->__toString(),
                                                                'uname_a' => $metadata['userName'],
                                                                'uname_b' => $userInfo->getName(),
                                                        ] );
                                                return $failHandler();
                                        }

                                } elseif ( $metadata['userName'] !== null ) { // Shouldn't happen, but just in case
                                        if ( $metadata['userName'] !== $userInfo->getName() ) {
                                                $this->logger->warning(
                                                        'Session "{session}": User name mismatch, {uname_a} !== {uname_b}',
                                                        [
                                                                'session' => $info->__toString(),
                                                                'uname_a' => $metadata['userName'],
                                                                'uname_b' => $userInfo->getName(),
                                                        ] );
                                                return $failHandler();
                                        }
                                } elseif ( !$userInfo->isAnon() ) {
                                        // The metadata in the session store entry indicates this is an anonymous session,
                                        // but the request metadata (e.g. the username cookie) says otherwise. Maybe the
                                        // user logged out but unsetting the cookies failed?
                                        $this->logger->warning(
                                                'Session "{session}": the session store entry is for an anonymous user, '
                                                        . 'but the session metadata indicates a non-anonynmous user',
                                                [
                                                        'session' => $info->__toString(),
                                                ] );
                                        return $failHandler();
                                }
                        }

                        // And if we have a token in the metadata, it must match the loaded/provided user.
                        // A mismatch probably means the session was invalidated.
                        if ( $metadata['userToken'] !== null &&
                                $userInfo->getToken() !== $metadata['userToken']
                        ) {
                                $this->logger->warning( 'Session "{session}": User token mismatch', [
                                        'session' => $info->__toString(),
                                ] );
                                return $failHandler();
                        }
                        if ( !$userInfo->isVerified() ) {
                                $newParams['userInfo'] = $userInfo->verified();
                        }

                        if ( !empty( $metadata['remember'] ) && !$info->wasRemembered() ) {
                                $newParams['remembered'] = true;
                        }
                        if ( !empty( $metadata['forceHTTPS'] ) && !$info->forceHTTPS() ) {
                                $newParams['forceHTTPS'] = true;
                        }
                        if ( !empty( $metadata['persisted'] ) && !$info->wasPersisted() ) {
                                $newParams['persisted'] = true;
                        }

                        if ( !$info->isIdSafe() ) {
                                $newParams['idIsSafe'] = true;
                        }
                } else {
                        // No metadata, so we can't load the provider if one wasn't given.
                        if ( $info->getProvider() === null ) {
                                $this->logger->warning(
                                        'Session "{session}": Null provider and no metadata',
                                        [
                                                'session' => $info->__toString(),
                                        ] );
                                return $failHandler();
                        }

                        // If no user was provided and no metadata, it must be anon.
                        if ( !$info->getUserInfo() ) {
                                if ( $info->getProvider()->canChangeUser() ) {
                                        $newParams['userInfo'] = UserInfo::newAnonymous();
                                } else {
                                        // This is a session provider bug - providers with canChangeUser() === false
                                        // should never return an anonymous SessionInfo.
                                        $this->logger->info(
                                                'Session "{session}": No user provided and provider cannot set user',
                                                [
                                                        'session' => $info->__toString(),
                                                ] );
                                        return $failHandler();
                                }
                        } elseif ( !$info->getUserInfo()->isVerified() ) {
                                // The session was not found in the session store, and the request contains no
                                // information beyond the session ID that could be used to verify it.
                                // Probably just a session timeout.
                                $this->logger->info(
                                        'Session "{session}": Unverified user provided and no metadata to auth it',
                                        [
                                                'session' => $info->__toString(),
                                        ] );
                                return $failHandler();
                        }

                        $data = false;
                        $metadata = false;

                        if ( !$info->getProvider()->persistsSessionId() && !$info->isIdSafe() ) {
                                // The ID doesn't come from the user, so it should be safe
                                // (and if not, nothing we can do about it anyway)
                                $newParams['idIsSafe'] = true;
                        }
                }

                // Construct the replacement SessionInfo, if necessary
                if ( $newParams ) {
                        $newParams['copyFrom'] = $info;
                        $info = new SessionInfo( $info->getPriority(), $newParams );
                }

                // Allow the provider to check the loaded SessionInfo
                $providerMetadata = $info->getProviderMetadata();
                if ( !$info->getProvider()->refreshSessionInfo( $info, $request, $providerMetadata ) ) {
                        return $failHandler();
                }
                if ( $providerMetadata !== $info->getProviderMetadata() ) {
                        $info = new SessionInfo( $info->getPriority(), [
                                'metadata' => $providerMetadata,
                                'copyFrom' => $info,
                        ] );
                }

                // Give hooks a chance to abort. Combined with the SessionMetadata
                // hook, this can allow for tying a session to an IP address or the
                // like.
                $reason = 'Hook aborted';
                if ( !$this->hookRunner->onSessionCheckInfo(
                        $reason, $info, $request, $metadata, $data )
                ) {
                        $this->logger->warning( 'Session "{session}": ' . $reason, [
                                'session' => $info->__toString(),
                        ] );
                        return $failHandler();
                }

                return true;
        }

        /**
         * Create a Session corresponding to the passed SessionInfo
         * @internal For use by a SessionProvider that needs to specially create its
         *  own Session. Most session providers won't need this.
         * @param SessionInfo $info
         * @param WebRequest $request
         * @return Session
         */
        public function getSessionFromInfo( SessionInfo $info, WebRequest $request ) {
                // @codeCoverageIgnoreStart
                if ( defined( 'MW_NO_SESSION' ) ) {
                        $ep = defined( 'MW_ENTRY_POINT' ) ? MW_ENTRY_POINT : 'this';

                        if ( MW_NO_SESSION === 'warn' ) {
                                // Undocumented safety case for converting existing entry points
                                $this->logger->error( 'Sessions are supposed to be disabled for this entry point', [
                                        'exception' => new \BadMethodCallException( "Sessions are disabled for $ep entry point" ),
                                ] );
                        } else {
                                throw new \BadMethodCallException( "Sessions are disabled for $ep entry point" );
                        }
                }
                // @codeCoverageIgnoreEnd

                $id = $info->getId();

                if ( !isset( $this->allSessionBackends[$id] ) ) {
                        if ( !isset( $this->allSessionIds[$id] ) ) {
                                $this->allSessionIds[$id] = new SessionId( $id );
                        }
                        $backend = new SessionBackend(
                                $this->allSessionIds[$id],
                                $info,
                                $this->store,
                                $this->logger,
                                $this->hookContainer,
                                $this->config->get( MainConfigNames::ObjectCacheSessionExpiry )
                        );
                        $this->allSessionBackends[$id] = $backend;
                        $delay = $backend->delaySave();
                } else {
                        $backend = $this->allSessionBackends[$id];
                        $delay = $backend->delaySave();
                        if ( $info->wasPersisted() ) {
                                $backend->persist();
                        }
                        if ( $info->wasRemembered() ) {
                                $backend->setRememberUser( true );
                        }
                }

                $request->setSessionId( $backend->getSessionId() );
                $session = $backend->getSession( $request );

                if ( !$info->isIdSafe() ) {
                        $session->resetId();
                }

                \Wikimedia\ScopedCallback::consume( $delay );
                return $session;
        }

        /**
         * Deregister a SessionBackend
         * @internal For use from \MediaWiki\Session\SessionBackend only
         * @param SessionBackend $backend
         */
        public function deregisterSessionBackend( SessionBackend $backend ) {
                $id = $backend->getId();
                if ( !isset( $this->allSessionBackends[$id] ) || !isset( $this->allSessionIds[$id] ) ||
                        $this->allSessionBackends[$id] !== $backend ||
                        $this->allSessionIds[$id] !== $backend->getSessionId()
                ) {
                        throw new InvalidArgumentException( 'Backend was not registered with this SessionManager' );
                }

                unset( $this->allSessionBackends[$id] );
                // Explicitly do not unset $this->allSessionIds[$id]
        }

        /**
         * Change a SessionBackend's ID
         * @internal For use from \MediaWiki\Session\SessionBackend only
         * @param SessionBackend $backend
         */
        public function changeBackendId( SessionBackend $backend ) {
                $sessionId = $backend->getSessionId();
                $oldId = (string)$sessionId;
                if ( !isset( $this->allSessionBackends[$oldId] ) || !isset( $this->allSessionIds[$oldId] ) ||
                        $this->allSessionBackends[$oldId] !== $backend ||
                        $this->allSessionIds[$oldId] !== $sessionId
                ) {
                        throw new InvalidArgumentException( 'Backend was not registered with this SessionManager' );
                }

                $newId = $this->generateSessionId();

                unset( $this->allSessionBackends[$oldId], $this->allSessionIds[$oldId] );
                $sessionId->setId( $newId );
                $this->allSessionBackends[$newId] = $backend;
                $this->allSessionIds[$newId] = $sessionId;
        }

        /**
         * Generate a new random session ID
         * @return string
         */
        public function generateSessionId() {
                $id = \Wikimedia\base_convert( \MWCryptRand::generateHex( 40 ), 16, 32, 32 );
                // Cache non-existence to avoid a later fetch
                $key = $this->store->makeKey( 'MWSession', $id );
                $this->store->set( $key, false, 0, BagOStuff::WRITE_CACHE_ONLY );
                return $id;
        }

        /**
         * Call setters on a PHPSessionHandler
         * @internal Use PhpSessionHandler::install()
         * @param PHPSessionHandler $handler
         */
        public function setupPHPSessionHandler( PHPSessionHandler $handler ) {
                $handler->setManager( $this, $this->store, $this->logger );
        }

        /**
         * Reset the internal caching for unit testing
         * @note Unit tests only
         * @internal
         */
        public static function resetCache() {
                if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
                        // @codeCoverageIgnoreStart
                        throw new LogicException( __METHOD__ . ' may only be called from unit tests!' );
                        // @codeCoverageIgnoreEnd
                }

                self::$globalSession = null;
                self::$globalSessionRequest = null;
        }

        private function logUnpersist( SessionInfo $info, WebRequest $request ) {
                $logData = [
                        'id' => $info->getId(),
                        'provider' => get_class( $info->getProvider() ),
                        'user' => '<anon>',
                        'supposedUser' => $info->getUserInfo() ? $info->getUserInfo()->getName() : null,
                        'clientip' => $request->getIP(),
                        'userAgent' => $request->getHeader( 'user-agent' ),
                ];
                if ( $info->getUserInfo() ) {
                        if ( !$info->getUserInfo()->isAnon() ) {
                                $logData['user'] = $info->getUserInfo()->getName();
                        }
                        $logData['userVerified'] = $info->getUserInfo()->isVerified();
                }
                $this->logger->info( 'Failed to load session, unpersisting', $logData );
        }

        /**
         * If the same session is suddenly used from a different IP, that's potentially due
         * to a session leak, so log it. In the vast majority of cases it is a false positive
         * due to a user switching connections, but we are interested in an audit track where
         * we can look up a specific username, so a noisy log is fine.
         * Also log changes to the mwuser cookie, an analytics cookie set by mediawiki.user.js
         * which should be a little less noisy.
         * @private For use in Setup.php only
         * @param Session|null $session For testing only
         */
        public function logPotentialSessionLeakage( ?Session $session = null ) {
                $proxyLookup = MediaWikiServices::getInstance()->getProxyLookup();
                $session = $session ?: self::getGlobalSession();
                $suspiciousIpExpiry = $this->config->get( MainConfigNames::SuspiciousIpExpiry );

                if ( $suspiciousIpExpiry === false
                        // We only care about logged-in users.
                        || !$session->isPersistent() || $session->getUser()->isAnon()
                        // We only care about cookie-based sessions.
                        || !( $session->getProvider() instanceof CookieSessionProvider )
                ) {
                        return;
                }
                try {
                        $ip = $session->getRequest()->getIP();
                } catch ( MWException $e ) {
                        return;
                }
                if ( $ip === '127.0.0.1' || $proxyLookup->isConfiguredProxy( $ip ) ) {
                        return;
                }
                $mwuser = $session->getRequest()->getCookie( 'mwuser-sessionId' );
                $now = (int)\MediaWiki\Utils\MWTimestamp::now( TS_UNIX );

                // Record (and possibly log) that the IP is using the current session.
                // Don't touch the stored data unless we are changing the IP or re-adding an expired one.
                // This is slightly inaccurate (when an existing IP is seen again, the expiry is not
                // extended) but that shouldn't make much difference and limits the session write frequency.
                $data = $session->get( 'SessionManager-logPotentialSessionLeakage', [] )
                        + [ 'ip' => null, 'mwuser' => null, 'timestamp' => 0 ];
                // Ignore old IP records; users change networks over time. mwuser is a session cookie and the
                // SessionManager session id is also a session cookie so there shouldn't be any problem there.
                if ( $data['ip'] &&
                        ( $now - $data['timestamp'] > $suspiciousIpExpiry )
                ) {
                        $data['ip'] = $data['timestamp'] = null;
                }

                if ( $data['ip'] !== $ip || $data['mwuser'] !== $mwuser ) {
                        $session->set( 'SessionManager-logPotentialSessionLeakage',
                                [ 'ip' => $ip, 'mwuser' => $mwuser, 'timestamp' => $now ] );
                }

                $ipChanged = ( $data['ip'] && $data['ip'] !== $ip );
                $mwuserChanged = ( $data['mwuser'] && $data['mwuser'] !== $mwuser );
                $logLevel = $message = null;
                $logData = [];
                // IPs change all the time. mwuser is a session cookie that's only set when missing,
                // so it should only change when the browser session ends which ends the SessionManager
                // session as well. Unless we are dealing with a very weird client, such as a bot that
                //manipulates cookies and can run Javascript, it should not change.
                // IP and mwuser changing at the same time would be *very* suspicious.
                if ( $ipChanged ) {
                        $logLevel = LogLevel::INFO;
                        $message = 'IP change within the same session';
                        $logData += [
                                'oldIp' => $data['ip'],
                                'oldIpRecorded' => $data['timestamp'],
                        ];
                }
                if ( $mwuserChanged ) {
                        $logLevel = LogLevel::NOTICE;
                        $message = 'mwuser change within the same session';
                        $logData += [
                                'oldMwuser' => $data['mwuser'],
                                'newMwuser' => $mwuser,
                        ];
                }
                if ( $ipChanged && $mwuserChanged ) {
                        $logLevel = LogLevel::WARNING;
                        $message = 'IP and mwuser change within the same session';
                }
                if ( $logLevel ) {
                        $logData += [
                                'session' => $session->getId(),
                                'user' => $session->getUser()->getName(),
                                'clientip' => $ip,
                                'userAgent' => $session->getRequest()->getHeader( 'user-agent' ),
                        ];
                        $logger = \MediaWiki\Logger\LoggerFactory::getInstance( 'session-ip' );
                        // @phan-suppress-next-line PhanTypeMismatchArgumentNullable message is set when used here
                        $logger->log( $logLevel, $message, $logData );
                }
        }

        // endregion -- end of Internal methods

}