includes/session/SessionManager.php

   1 <?php
   2 /**
   3  * MediaWiki\Session entry point
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Session
  22  */
  23
  24 namespace MediaWiki\Session;
  25
  26 use Psr\Log\LoggerInterface;
  27 use BagOStuff;
  28 use CachedBagOStuff;
  29 use Config;
  30 use FauxRequest;
  31 use User;
  32 use WebRequest;
  33
  34 /**
  35  * This serves as the entry point to the MediaWiki session handling system.
  36  *
  37  * @ingroup Session
  38  * @since 1.27
  39  */
  40 final class SessionManager implements SessionManagerInterface {
  41         /** @var SessionManager|null */
  42         private static $instance = null;
  43
  44         /** @var Session|null */
  45         private static $globalSession = null;
  46
  47         /** @var WebRequest|null */
  48         private static $globalSessionRequest = null;
  49
  50         /** @var LoggerInterface */
  51         private $logger;
  52
  53         /** @var Config */
  54         private $config;
  55
  56         /** @var CachedBagOStuff|null */
  57         private $store;
  58
  59         /** @var SessionProvider[] */
  60         private $sessionProviders = null;
  61
  62         /** @var string[] */
  63         private $varyCookies = null;
  64
  65         /** @var array */
  66         private $varyHeaders = null;
  67
  68         /** @var SessionBackend[] */
  69         private $allSessionBackends = [];
  70
  71         /** @var SessionId[] */
  72         private $allSessionIds = [];
  73
  74         /** @var string[] */
  75         private $preventUsers = [];
  76
  77         /**
  78          * Get the global SessionManager
  79          * @return SessionManagerInterface
  80          *  (really a SessionManager, but this is to make IDEs less confused)
  81          */
  82         public static function singleton() {
  83                 if ( self::$instance === null ) {
  84                         self::$instance = new self();
  85                 }
  86                 return self::$instance;
  87         }
  88
  89         /**
  90          * Get the "global" session
  91          *
  92          * If PHP's session_id() has been set, returns that session. Otherwise
  93          * returns the session for RequestContext::getMain()->getRequest().
  94          *
  95          * @return Session
  96          */
  97         public static function getGlobalSession() {
  98                 if ( !PHPSessionHandler::isEnabled() ) {
  99                         $id = '';
 100                 } else {
 101                         $id = session_id();
 102                 }
 103
 104                 $request = \RequestContext::getMain()->getRequest();
 105                 if (
 106                         !self::$globalSession // No global session is set up yet
 107                         || self::$globalSessionRequest !== $request // The global WebRequest changed
 108                         || $id !== '' && self::$globalSession->getId() !== $id // Someone messed with session_id()
 109                 ) {
 110                         self::$globalSessionRequest = $request;
 111                         if ( $id === '' ) {
 112                                 // session_id() wasn't used, so fetch the Session from the WebRequest.
 113                                 // We use $request->getSession() instead of $singleton->getSessionForRequest()
 114                                 // because doing the latter would require a public
 115                                 // "$request->getSessionId()" method that would confuse end
 116                                 // users by returning SessionId|null where they'd expect it to
 117                                 // be short for $request->getSession()->getId(), and would
 118                                 // wind up being a duplicate of the code in
 119                                 // $request->getSession() anyway.
 120                                 self::$globalSession = $request->getSession();
 121                         } else {
 122                                 // Someone used session_id(), so we need to follow suit.
 123                                 // Note this overwrites whatever session might already be
 124                                 // associated with $request with the one for $id.
 125                                 self::$globalSession = self::singleton()->getSessionById( $id, true, $request )
 126                                         ?: $request->getSession();
 127                         }
 128                 }
 129                 return self::$globalSession;
 130         }
 131
 132         /**
 133          * @param array $options
 134          *  - config: Config to fetch configuration from. Defaults to the default 'main' config.
 135          *  - logger: LoggerInterface to use for logging. Defaults to the 'session' channel.
 136          *  - store: BagOStuff to store session data in.
 137          */
 138         public function __construct( $options = [] ) {
 139                 if ( isset( $options['config'] ) ) {
 140                         $this->config = $options['config'];
 141                         if ( !$this->config instanceof Config ) {
 142                                 throw new \InvalidArgumentException(
 143                                         '$options[\'config\'] must be an instance of Config'
 144                                 );
 145                         }
 146                 } else {
 147                         $this->config = \ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
 148                 }
 149
 150                 if ( isset( $options['logger'] ) ) {
 151                         if ( !$options['logger'] instanceof LoggerInterface ) {
 152                                 throw new \InvalidArgumentException(
 153                                         '$options[\'logger\'] must be an instance of LoggerInterface'
 154                                 );
 155                         }
 156                         $this->setLogger( $options['logger'] );
 157                 } else {
 158                         $this->setLogger( \MediaWiki\Logger\LoggerFactory::getInstance( 'session' ) );
 159                 }
 160
 161                 if ( isset( $options['store'] ) ) {
 162                         if ( !$options['store'] instanceof BagOStuff ) {
 163                                 throw new \InvalidArgumentException(
 164                                         '$options[\'store\'] must be an instance of BagOStuff'
 165                                 );
 166                         }
 167                         $store = $options['store'];
 168                 } else {
 169                         $store = \ObjectCache::getInstance( $this->config->get( 'SessionCacheType' ) );
 170                 }
 171                 $this->store = $store instanceof CachedBagOStuff ? $store : new CachedBagOStuff( $store );
 172
 173                 register_shutdown_function( [ $this, 'shutdown' ] );
 174         }
 175
 176         public function setLogger( LoggerInterface $logger ) {
 177                 $this->logger = $logger;
 178         }
 179
 180         public function getSessionForRequest( WebRequest $request ) {
 181                 $info = $this->getSessionInfoForRequest( $request );
 182
 183                 if ( !$info ) {
 184                         $session = $this->getEmptySession( $request );
 185                 } else {
 186                         $session = $this->getSessionFromInfo( $info, $request );
 187                 }
 188                 return $session;
 189         }
 190
 191         public function getSessionById( $id, $create = false, WebRequest $request = null ) {
 192                 if ( !self::validateSessionId( $id ) ) {
 193                         throw new \InvalidArgumentException( 'Invalid session ID' );
 194                 }
 195                 if ( !$request ) {
 196                         $request = new FauxRequest;
 197                 }
 198
 199                 $session = null;
 200
 201                 // Test this here to provide a better log message for the common case
 202                 // of "no such ID"
 203                 $key = wfMemcKey( 'MWSession', $id );
 204                 if ( is_array( $this->store->get( $key ) ) ) {
 205                         $info = new SessionInfo( SessionInfo::MIN_PRIORITY, [ 'id' => $id, 'idIsSafe' => true ] );
 206                         if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
 207                                 $session = $this->getSessionFromInfo( $info, $request );
 208                         }
 209                 }
 210
 211                 if ( $create && $session === null ) {
 212                         $ex = null;
 213                         try {
 214                                 $session = $this->getEmptySessionInternal( $request, $id );
 215                         } catch ( \Exception $ex ) {
 216                                 $this->logger->error( 'Failed to create empty session: {exception}',
 217                                         [
 218                                                 'method' => __METHOD__,
 219                                                 'exception' => $ex,
 220                                 ] );
 221                                 $session = null;
 222                         }
 223                 }
 224
 225                 return $session;
 226         }
 227
 228         public function getEmptySession( WebRequest $request = null ) {
 229                 return $this->getEmptySessionInternal( $request );
 230         }
 231
 232         /**
 233          * @see SessionManagerInterface::getEmptySession
 234          * @param WebRequest|null $request
 235          * @param string|null $id ID to force on the new session
 236          * @return Session
 237          */
 238         private function getEmptySessionInternal( WebRequest $request = null, $id = null ) {
 239                 if ( $id !== null ) {
 240                         if ( !self::validateSessionId( $id ) ) {
 241                                 throw new \InvalidArgumentException( 'Invalid session ID' );
 242                         }
 243
 244                         $key = wfMemcKey( 'MWSession', $id );
 245                         if ( is_array( $this->store->get( $key ) ) ) {
 246                                 throw new \InvalidArgumentException( 'Session ID already exists' );
 247                         }
 248                 }
 249                 if ( !$request ) {
 250                         $request = new FauxRequest;
 251                 }
 252
 253                 $infos = [];
 254                 foreach ( $this->getProviders() as $provider ) {
 255                         $info = $provider->newSessionInfo( $id );
 256                         if ( !$info ) {
 257                                 continue;
 258                         }
 259                         if ( $info->getProvider() !== $provider ) {
 260                                 throw new \UnexpectedValueException(
 261                                         "$provider returned an empty session info for a different provider: $info"
 262                                 );
 263                         }
 264                         if ( $id !== null && $info->getId() !== $id ) {
 265                                 throw new \UnexpectedValueException(
 266                                         "$provider returned empty session info with a wrong id: " .
 267                                                 $info->getId() . ' != ' . $id
 268                                 );
 269                         }
 270                         if ( !$info->isIdSafe() ) {
 271                                 throw new \UnexpectedValueException(
 272                                         "$provider returned empty session info with id flagged unsafe"
 273                                 );
 274                         }
 275                         $compare = $infos ? SessionInfo::compare( $infos[0], $info ) : -1;
 276                         if ( $compare > 0 ) {
 277                                 continue;
 278                         }
 279                         if ( $compare === 0 ) {
 280                                 $infos[] = $info;
 281                         } else {
 282                                 $infos = [ $info ];
 283                         }
 284                 }
 285
 286                 // Make sure there's exactly one
 287                 if ( count( $infos ) > 1 ) {
 288                         throw new \UnexpectedValueException(
 289                                 'Multiple empty sessions tied for top priority: ' . join( ', ', $infos )
 290                         );
 291                 } elseif ( count( $infos ) < 1 ) {
 292                         throw new \UnexpectedValueException( 'No provider could provide an empty session!' );
 293                 }
 294
 295                 return $this->getSessionFromInfo( $infos[0], $request );
 296         }
 297
 298         public function getVaryHeaders() {
 299                 if ( $this->varyHeaders === null ) {
 300                         $headers = [];
 301                         foreach ( $this->getProviders() as $provider ) {
 302                                 foreach ( $provider->getVaryHeaders() as $header => $options ) {
 303                                         if ( !isset( $headers[$header] ) ) {
 304                                                 $headers[$header] = [];
 305                                         }
 306                                         if ( is_array( $options ) ) {
 307                                                 $headers[$header] = array_unique( array_merge( $headers[$header], $options ) );
 308                                         }
 309                                 }
 310                         }
 311                         $this->varyHeaders = $headers;
 312                 }
 313                 return $this->varyHeaders;
 314         }
 315
 316         public function getVaryCookies() {
 317                 if ( $this->varyCookies === null ) {
 318                         $cookies = [];
 319                         foreach ( $this->getProviders() as $provider ) {
 320                                 $cookies = array_merge( $cookies, $provider->getVaryCookies() );
 321                         }
 322                         $this->varyCookies = array_values( array_unique( $cookies ) );
 323                 }
 324                 return $this->varyCookies;
 325         }
 326
 327         /**
 328          * Validate a session ID
 329          * @param string $id
 330          * @return bool
 331          */
 332         public static function validateSessionId( $id ) {
 333                 return is_string( $id ) && preg_match( '/^[a-zA-Z0-9_-]{32,}$/', $id );
 334         }
 335
 336         /**
 337          * @name Internal methods
 338          * @{
 339          */
 340
 341         /**
 342          * Auto-create the given user, if necessary
 343          * @private Don't call this yourself. Let Setup.php do it for you at the right time.
 344          * @note This more properly belongs in AuthManager, but we need it now.
 345          *  When AuthManager comes, this will be deprecated and will pass-through
 346          *  to the corresponding AuthManager method.
 347          * @param User $user User to auto-create
 348          * @return bool Success
 349          */
 350         public static function autoCreateUser( User $user ) {
 351                 global $wgAuth;
 352
 353                 $logger = self::singleton()->logger;
 354
 355                 // Much of this code is based on that in CentralAuth
 356
 357                 // Try the local user from the slave DB
 358                 $localId = User::idFromName( $user->getName() );
 359                 $flags = 0;
 360
 361                 // Fetch the user ID from the master, so that we don't try to create the user
 362                 // when they already exist, due to replication lag
 363                 // @codeCoverageIgnoreStart
 364                 if ( !$localId && wfGetLB()->getReaderIndex() != 0 ) {
 365                         $localId = User::idFromName( $user->getName(), User::READ_LATEST );
 366                         $flags = User::READ_LATEST;
 367                 }
 368                 // @codeCoverageIgnoreEnd
 369
 370                 if ( $localId ) {
 371                         // User exists after all.
 372                         $user->setId( $localId );
 373                         $user->loadFromId( $flags );
 374                         return false;
 375                 }
 376
 377                 // Denied by AuthPlugin? But ignore AuthPlugin itself.
 378                 if ( get_class( $wgAuth ) !== 'AuthPlugin' && !$wgAuth->autoCreate() ) {
 379                         $logger->debug( __METHOD__ . ': denied by AuthPlugin' );
 380                         $user->setId( 0 );
 381                         $user->loadFromId();
 382                         return false;
 383                 }
 384
 385                 // Wiki is read-only?
 386                 if ( wfReadOnly() ) {
 387                         $logger->debug( __METHOD__ . ': denied by wfReadOnly()' );
 388                         $user->setId( 0 );
 389                         $user->loadFromId();
 390                         return false;
 391                 }
 392
 393                 $userName = $user->getName();
 394
 395                 // Check the session, if we tried to create this user already there's
 396                 // no point in retrying.
 397                 $session = self::getGlobalSession();
 398                 $reason = $session->get( 'MWSession::AutoCreateBlacklist' );
 399                 if ( $reason ) {
 400                         $logger->debug( __METHOD__ . ": blacklisted in session ($reason)" );
 401                         $user->setId( 0 );
 402                         $user->loadFromId();
 403                         return false;
 404                 }
 405
 406                 // Is the IP user able to create accounts?
 407                 $anon = new User;
 408                 if ( !$anon->isAllowedAny( 'createaccount', 'autocreateaccount' )
 409                         || $anon->isBlockedFromCreateAccount()
 410                 ) {
 411                         // Blacklist the user to avoid repeated DB queries subsequently
 412                         $logger->debug( __METHOD__ . ': user is blocked from this wiki, blacklisting' );
 413                         $session->set( 'MWSession::AutoCreateBlacklist', 'blocked', 600 );
 414                         $session->persist();
 415                         $user->setId( 0 );
 416                         $user->loadFromId();
 417                         return false;
 418                 }
 419
 420                 // Check for validity of username
 421                 if ( !User::isCreatableName( $userName ) ) {
 422                         $logger->debug( __METHOD__ . ': Invalid username, blacklisting' );
 423                         $session->set( 'MWSession::AutoCreateBlacklist', 'invalid username', 600 );
 424                         $session->persist();
 425                         $user->setId( 0 );
 426                         $user->loadFromId();
 427                         return false;
 428                 }
 429
 430                 // Give other extensions a chance to stop auto creation.
 431                 $user->loadDefaults( $userName );
 432                 $abortMessage = '';
 433                 if ( !\Hooks::run( 'AbortAutoAccount', [ $user, &$abortMessage ] ) ) {
 434                         // In this case we have no way to return the message to the user,
 435                         // but we can log it.
 436                         $logger->debug( __METHOD__ . ": denied by hook: $abortMessage" );
 437                         $session->set( 'MWSession::AutoCreateBlacklist', "hook aborted: $abortMessage", 600 );
 438                         $session->persist();
 439                         $user->setId( 0 );
 440                         $user->loadFromId();
 441                         return false;
 442                 }
 443
 444                 // Make sure the name has not been changed
 445                 if ( $user->getName() !== $userName ) {
 446                         $user->setId( 0 );
 447                         $user->loadFromId();
 448                         throw new \UnexpectedValueException(
 449                                 'AbortAutoAccount hook tried to change the user name'
 450                         );
 451                 }
 452
 453                 // Ignore warnings about master connections/writes...hard to avoid here
 454                 \Profiler::instance()->getTransactionProfiler()->resetExpectations();
 455
 456                 $cache = \ObjectCache::getLocalClusterInstance();
 457                 $backoffKey = wfMemcKey( 'MWSession', 'autocreate-failed', md5( $userName ) );
 458                 if ( $cache->get( $backoffKey ) ) {
 459                         $logger->debug( __METHOD__ . ': denied by prior creation attempt failures' );
 460                         $user->setId( 0 );
 461                         $user->loadFromId();
 462                         return false;
 463                 }
 464
 465                 // Checks passed, create the user...
 466                 $from = isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : 'CLI';
 467                 $logger->info( __METHOD__ . ': creating new user ({username}) - from: {url}',
 468                         [
 469                                 'username' => $userName,
 470                                 'url' => $from,
 471                 ] );
 472
 473                 try {
 474                         // Insert the user into the local DB master
 475                         $status = $user->addToDatabase();
 476                         if ( !$status->isOK() ) {
 477                                 // @codeCoverageIgnoreStart
 478                                 // double-check for a race condition (T70012)
 479                                 $id = User::idFromName( $user->getName(), User::READ_LATEST );
 480                                 if ( $id ) {
 481                                         $logger->info( __METHOD__ . ': tried to autocreate existing user',
 482                                                 [
 483                                                         'username' => $userName,
 484                                                 ] );
 485                                 } else {
 486                                         $logger->error( __METHOD__ . ': failed with message ' . $status->getWikiText(),
 487                                                 [
 488                                                         'username' => $userName,
 489                                                 ] );
 490                                 }
 491                                 $user->setId( $id );
 492                                 $user->loadFromId( User::READ_LATEST );
 493                                 return false;
 494                                 // @codeCoverageIgnoreEnd
 495                         }
 496                 } catch ( \Exception $ex ) {
 497                         // @codeCoverageIgnoreStart
 498                         $logger->error( __METHOD__ . ': failed with exception {exception}', [
 499                                 'exception' => $ex,
 500                                 'username' => $userName,
 501                         ] );
 502                         // Do not keep throwing errors for a while
 503                         $cache->set( $backoffKey, 1, 600 );
 504                         // Bubble up error; which should normally trigger DB rollbacks
 505                         throw $ex;
 506                         // @codeCoverageIgnoreEnd
 507                 }
 508
 509                 # Notify AuthPlugin
 510                 $tmpUser = $user;
 511                 $wgAuth->initUser( $tmpUser, true );
 512                 if ( $tmpUser !== $user ) {
 513                         $logger->warning( __METHOD__ . ': ' .
 514                                 get_class( $wgAuth ) . '::initUser() replaced the user object' );
 515                 }
 516
 517                 # Notify hooks (e.g. Newuserlog)
 518                 \Hooks::run( 'AuthPluginAutoCreate', [ $user ] );
 519                 \Hooks::run( 'LocalUserCreated', [ $user, true ] );
 520
 521                 $user->saveSettings();
 522
 523                 # Update user count
 524                 \DeferredUpdates::addUpdate( new \SiteStatsUpdate( 0, 0, 0, 0, 1 ) );
 525
 526                 # Watch user's userpage and talk page
 527                 $user->addWatch( $user->getUserPage(), \WatchedItem::IGNORE_USER_RIGHTS );
 528
 529                 return true;
 530         }
 531
 532         /**
 533          * Prevent future sessions for the user
 534          *
 535          * The intention is that the named account will never again be usable for
 536          * normal login (i.e. there is no way to undo the prevention of access).
 537          *
 538          * @private For use from \\User::newSystemUser only
 539          * @param string $username
 540          */
 541         public function preventSessionsForUser( $username ) {
 542                 $this->preventUsers[$username] = true;
 543
 544                 // Instruct the session providers to kill any other sessions too.
 545                 foreach ( $this->getProviders() as $provider ) {
 546                         $provider->preventSessionsForUser( $username );
 547                 }
 548         }
 549
 550         /**
 551          * Test if a user is prevented
 552          * @private For use from SessionBackend only
 553          * @param string $username
 554          * @return bool
 555          */
 556         public function isUserSessionPrevented( $username ) {
 557                 return !empty( $this->preventUsers[$username] );
 558         }
 559
 560         /**
 561          * Get the available SessionProviders
 562          * @return SessionProvider[]
 563          */
 564         protected function getProviders() {
 565                 if ( $this->sessionProviders === null ) {
 566                         $this->sessionProviders = [];
 567                         foreach ( $this->config->get( 'SessionProviders' ) as $spec ) {
 568                                 $provider = \ObjectFactory::getObjectFromSpec( $spec );
 569                                 $provider->setLogger( $this->logger );
 570                                 $provider->setConfig( $this->config );
 571                                 $provider->setManager( $this );
 572                                 if ( isset( $this->sessionProviders[(string)$provider] ) ) {
 573                                         throw new \UnexpectedValueException( "Duplicate provider name \"$provider\"" );
 574                                 }
 575                                 $this->sessionProviders[(string)$provider] = $provider;
 576                         }
 577                 }
 578                 return $this->sessionProviders;
 579         }
 580
 581         /**
 582          * Get a session provider by name
 583          *
 584          * Generally, this will only be used by internal implementation of some
 585          * special session-providing mechanism. General purpose code, if it needs
 586          * to access a SessionProvider at all, will use Session::getProvider().
 587          *
 588          * @param string $name
 589          * @return SessionProvider|null
 590          */
 591         public function getProvider( $name ) {
 592                 $providers = $this->getProviders();
 593                 return isset( $providers[$name] ) ? $providers[$name] : null;
 594         }
 595
 596         /**
 597          * Save all active sessions on shutdown
 598          * @private For internal use with register_shutdown_function()
 599          */
 600         public function shutdown() {
 601                 if ( $this->allSessionBackends ) {
 602                         $this->logger->debug( 'Saving all sessions on shutdown' );
 603                         if ( session_id() !== '' ) {
 604                                 // @codeCoverageIgnoreStart
 605                                 session_write_close();
 606                         }
 607                         // @codeCoverageIgnoreEnd
 608                         foreach ( $this->allSessionBackends as $backend ) {
 609                                 $backend->save( true );
 610                         }
 611                 }
 612         }
 613
 614         /**
 615          * Fetch the SessionInfo(s) for a request
 616          * @param WebRequest $request
 617          * @return SessionInfo|null
 618          */
 619         private function getSessionInfoForRequest( WebRequest $request ) {
 620                 // Call all providers to fetch "the" session
 621                 $infos = [];
 622                 foreach ( $this->getProviders() as $provider ) {
 623                         $info = $provider->provideSessionInfo( $request );
 624                         if ( !$info ) {
 625                                 continue;
 626                         }
 627                         if ( $info->getProvider() !== $provider ) {
 628                                 throw new \UnexpectedValueException(
 629                                         "$provider returned session info for a different provider: $info"
 630                                 );
 631                         }
 632                         $infos[] = $info;
 633                 }
 634
 635                 // Sort the SessionInfos. Then find the first one that can be
 636                 // successfully loaded, and then all the ones after it with the same
 637                 // priority.
 638                 usort( $infos, 'MediaWiki\\Session\\SessionInfo::compare' );
 639                 $retInfos = [];
 640                 while ( $infos ) {
 641                         $info = array_pop( $infos );
 642                         if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
 643                                 $retInfos[] = $info;
 644                                 while ( $infos ) {
 645                                         $info = array_pop( $infos );
 646                                         if ( SessionInfo::compare( $retInfos[0], $info ) ) {
 647                                                 // We hit a lower priority, stop checking.
 648                                                 break;
 649                                         }
 650                                         if ( $this->loadSessionInfoFromStore( $info, $request ) ) {
 651                                                 // This is going to error out below, but we want to
 652                                                 // provide a complete list.
 653                                                 $retInfos[] = $info;
 654                                         }
 655                                 }
 656                         }
 657                 }
 658
 659                 if ( count( $retInfos ) > 1 ) {
 660                         $ex = new \OverflowException(
 661                                 'Multiple sessions for this request tied for top priority: ' . join( ', ', $retInfos )
 662                         );
 663                         $ex->sessionInfos = $retInfos;
 664                         throw $ex;
 665                 }
 666
 667                 return $retInfos ? $retInfos[0] : null;
 668         }
 669
 670         /**
 671          * Load and verify the session info against the store
 672          *
 673          * @param SessionInfo &$info Will likely be replaced with an updated SessionInfo instance
 674          * @param WebRequest $request
 675          * @return bool Whether the session info matches the stored data (if any)
 676          */
 677         private function loadSessionInfoFromStore( SessionInfo &$info, WebRequest $request ) {
 678                 $key = wfMemcKey( 'MWSession', $info->getId() );
 679                 $blob = $this->store->get( $key );
 680
 681                 $newParams = [];
 682
 683                 if ( $blob !== false ) {
 684                         // Sanity check: blob must be an array, if it's saved at all
 685                         if ( !is_array( $blob ) ) {
 686                                 $this->logger->warning( 'Session "{session}": Bad data', [
 687                                         'session' => $info,
 688                                 ] );
 689                                 $this->store->delete( $key );
 690                                 return false;
 691                         }
 692
 693                         // Sanity check: blob has data and metadata arrays
 694                         if ( !isset( $blob['data'] ) || !is_array( $blob['data'] ) ||
 695                                 !isset( $blob['metadata'] ) || !is_array( $blob['metadata'] )
 696                         ) {
 697                                 $this->logger->warning( 'Session "{session}": Bad data structure', [
 698                                         'session' => $info,
 699                                 ] );
 700                                 $this->store->delete( $key );
 701                                 return false;
 702                         }
 703
 704                         $data = $blob['data'];
 705                         $metadata = $blob['metadata'];
 706
 707                         // Sanity check: metadata must be an array and must contain certain
 708                         // keys, if it's saved at all
 709                         if ( !array_key_exists( 'userId', $metadata ) ||
 710                                 !array_key_exists( 'userName', $metadata ) ||
 711                                 !array_key_exists( 'userToken', $metadata ) ||
 712                                 !array_key_exists( 'provider', $metadata )
 713                         ) {
 714                                 $this->logger->warning( 'Session "{session}": Bad metadata', [
 715                                         'session' => $info,
 716                                 ] );
 717                                 $this->store->delete( $key );
 718                                 return false;
 719                         }
 720
 721                         // First, load the provider from metadata, or validate it against the metadata.
 722                         $provider = $info->getProvider();
 723                         if ( $provider === null ) {
 724                                 $newParams['provider'] = $provider = $this->getProvider( $metadata['provider'] );
 725                                 if ( !$provider ) {
 726                                         $this->logger->warning(
 727                                                 'Session "{session}": Unknown provider ' . $metadata['provider'],
 728                                                 [
 729                                                         'session' => $info,
 730                                                 ]
 731                                         );
 732                                         $this->store->delete( $key );
 733                                         return false;
 734                                 }
 735                         } elseif ( $metadata['provider'] !== (string)$provider ) {
 736                                 $this->logger->warning( 'Session "{session}": Wrong provider ' .
 737                                         $metadata['provider'] . ' !== ' . $provider,
 738                                         [
 739                                                 'session' => $info,
 740                                 ] );
 741                                 return false;
 742                         }
 743
 744                         // Load provider metadata from metadata, or validate it against the metadata
 745                         $providerMetadata = $info->getProviderMetadata();
 746                         if ( isset( $metadata['providerMetadata'] ) ) {
 747                                 if ( $providerMetadata === null ) {
 748                                         $newParams['metadata'] = $metadata['providerMetadata'];
 749                                 } else {
 750                                         try {
 751                                                 $newProviderMetadata = $provider->mergeMetadata(
 752                                                         $metadata['providerMetadata'], $providerMetadata
 753                                                 );
 754                                                 if ( $newProviderMetadata !== $providerMetadata ) {
 755                                                         $newParams['metadata'] = $newProviderMetadata;
 756                                                 }
 757                                         } catch ( MetadataMergeException $ex ) {
 758                                                 $this->logger->warning(
 759                                                         'Session "{session}": Metadata merge failed: {exception}',
 760                                                         [
 761                                                                 'session' => $info,
 762                                                                 'exception' => $ex,
 763                                                         ] + $ex->getContext()
 764                                                 );
 765                                                 return false;
 766                                         }
 767                                 }
 768                         }
 769
 770                         // Next, load the user from metadata, or validate it against the metadata.
 771                         $userInfo = $info->getUserInfo();
 772                         if ( !$userInfo ) {
 773                                 // For loading, id is preferred to name.
 774                                 try {
 775                                         if ( $metadata['userId'] ) {
 776                                                 $userInfo = UserInfo::newFromId( $metadata['userId'] );
 777                                         } elseif ( $metadata['userName'] !== null ) { // Shouldn't happen, but just in case
 778                                                 $userInfo = UserInfo::newFromName( $metadata['userName'] );
 779                                         } else {
 780                                                 $userInfo = UserInfo::newAnonymous();
 781                                         }
 782                                 } catch ( \InvalidArgumentException $ex ) {
 783                                         $this->logger->error( 'Session "{session}": {exception}', [
 784                                                 'session' => $info,
 785                                                 'exception' => $ex,
 786                                         ] );
 787                                         return false;
 788                                 }
 789                                 $newParams['userInfo'] = $userInfo;
 790                         } else {
 791                                 // User validation passes if user ID matches, or if there
 792                                 // is no saved ID and the names match.
 793                                 if ( $metadata['userId'] ) {
 794                                         if ( $metadata['userId'] !== $userInfo->getId() ) {
 795                                                 $this->logger->warning(
 796                                                         'Session "{session}": User ID mismatch, {uid_a} !== {uid_b}',
 797                                                         [
 798                                                                 'session' => $info,
 799                                                                 'uid_a' => $metadata['userId'],
 800                                                                 'uid_b' => $userInfo->getId(),
 801                                                 ] );
 802                                                 return false;
 803                                         }
 804
 805                                         // If the user was renamed, probably best to fail here.
 806                                         if ( $metadata['userName'] !== null &&
 807                                                 $userInfo->getName() !== $metadata['userName']
 808                                         ) {
 809                                                 $this->logger->warning(
 810                                                         'Session "{session}": User ID matched but name didn\'t (rename?), {uname_a} !== {uname_b}',
 811                                                         [
 812                                                                 'session' => $info,
 813                                                                 'uname_a' => $metadata['userName'],
 814                                                                 'uname_b' => $userInfo->getName(),
 815                                                 ] );
 816                                                 return false;
 817                                         }
 818
 819                                 } elseif ( $metadata['userName'] !== null ) { // Shouldn't happen, but just in case
 820                                         if ( $metadata['userName'] !== $userInfo->getName() ) {
 821                                                 $this->logger->warning(
 822                                                         'Session "{session}": User name mismatch, {uname_a} !== {uname_b}',
 823                                                         [
 824                                                                 'session' => $info,
 825                                                                 'uname_a' => $metadata['userName'],
 826                                                                 'uname_b' => $userInfo->getName(),
 827                                                 ] );
 828                                                 return false;
 829                                         }
 830                                 } elseif ( !$userInfo->isAnon() ) {
 831                                         // Metadata specifies an anonymous user, but the passed-in
 832                                         // user isn't anonymous.
 833                                         $this->logger->warning(
 834                                                 'Session "{session}": Metadata has an anonymous user, but a non-anon user was provided',
 835                                                 [
 836                                                         'session' => $info,
 837                                         ] );
 838                                         return false;
 839                                 }
 840                         }
 841
 842                         // And if we have a token in the metadata, it must match the loaded/provided user.
 843                         if ( $metadata['userToken'] !== null &&
 844                                 $userInfo->getToken() !== $metadata['userToken']
 845                         ) {
 846                                 $this->logger->warning( 'Session "{session}": User token mismatch', [
 847                                         'session' => $info,
 848                                 ] );
 849                                 return false;
 850                         }
 851                         if ( !$userInfo->isVerified() ) {
 852                                 $newParams['userInfo'] = $userInfo->verified();
 853                         }
 854
 855                         if ( !empty( $metadata['remember'] ) && !$info->wasRemembered() ) {
 856                                 $newParams['remembered'] = true;
 857                         }
 858                         if ( !empty( $metadata['forceHTTPS'] ) && !$info->forceHTTPS() ) {
 859                                 $newParams['forceHTTPS'] = true;
 860                         }
 861                         if ( !empty( $metadata['persisted'] ) && !$info->wasPersisted() ) {
 862                                 $newParams['persisted'] = true;
 863                         }
 864
 865                         if ( !$info->isIdSafe() ) {
 866                                 $newParams['idIsSafe'] = true;
 867                         }
 868                 } else {
 869                         // No metadata, so we can't load the provider if one wasn't given.
 870                         if ( $info->getProvider() === null ) {
 871                                 $this->logger->warning(
 872                                         'Session "{session}": Null provider and no metadata',
 873                                         [
 874                                                 'session' => $info,
 875                                 ] );
 876                                 return false;
 877                         }
 878
 879                         // If no user was provided and no metadata, it must be anon.
 880                         if ( !$info->getUserInfo() ) {
 881                                 if ( $info->getProvider()->canChangeUser() ) {
 882                                         $newParams['userInfo'] = UserInfo::newAnonymous();
 883                                 } else {
 884                                         $this->logger->info(
 885                                                 'Session "{session}": No user provided and provider cannot set user',
 886                                                 [
 887                                                         'session' => $info,
 888                                         ] );
 889                                         return false;
 890                                 }
 891                         } elseif ( !$info->getUserInfo()->isVerified() ) {
 892                                 $this->logger->warning(
 893                                         'Session "{session}": Unverified user provided and no metadata to auth it',
 894                                         [
 895                                                 'session' => $info,
 896                                 ] );
 897                                 return false;
 898                         }
 899
 900                         $data = false;
 901                         $metadata = false;
 902
 903                         if ( !$info->getProvider()->persistsSessionId() && !$info->isIdSafe() ) {
 904                                 // The ID doesn't come from the user, so it should be safe
 905                                 // (and if not, nothing we can do about it anyway)
 906                                 $newParams['idIsSafe'] = true;
 907                         }
 908                 }
 909
 910                 // Construct the replacement SessionInfo, if necessary
 911                 if ( $newParams ) {
 912                         $newParams['copyFrom'] = $info;
 913                         $info = new SessionInfo( $info->getPriority(), $newParams );
 914                 }
 915
 916                 // Allow the provider to check the loaded SessionInfo
 917                 $providerMetadata = $info->getProviderMetadata();
 918                 if ( !$info->getProvider()->refreshSessionInfo( $info, $request, $providerMetadata ) ) {
 919                         return false;
 920                 }
 921                 if ( $providerMetadata !== $info->getProviderMetadata() ) {
 922                         $info = new SessionInfo( $info->getPriority(), [
 923                                 'metadata' => $providerMetadata,
 924                                 'copyFrom' => $info,
 925                         ] );
 926                 }
 927
 928                 // Give hooks a chance to abort. Combined with the SessionMetadata
 929                 // hook, this can allow for tying a session to an IP address or the
 930                 // like.
 931                 $reason = 'Hook aborted';
 932                 if ( !\Hooks::run(
 933                         'SessionCheckInfo',
 934                         [ &$reason, $info, $request, $metadata, $data ]
 935                 ) ) {
 936                         $this->logger->warning( 'Session "{session}": ' . $reason, [
 937                                 'session' => $info,
 938                         ] );
 939                         return false;
 940                 }
 941
 942                 return true;
 943         }
 944
 945         /**
 946          * Create a session corresponding to the passed SessionInfo
 947          * @private For use by a SessionProvider that needs to specially create its
 948          *  own session.
 949          * @param SessionInfo $info
 950          * @param WebRequest $request
 951          * @return Session
 952          */
 953         public function getSessionFromInfo( SessionInfo $info, WebRequest $request ) {
 954                 if ( defined( 'MW_NO_SESSION' ) ) {
 955                         if ( MW_NO_SESSION === 'warn' ) {
 956                                 // Undocumented safety case for converting existing entry points
 957                                 $this->logger->error( 'Sessions are supposed to be disabled for this entry point' );
 958                         } else {
 959                                 throw new \BadMethodCallException( 'Sessions are disabled for this entry point' );
 960                         }
 961                 }
 962
 963                 $id = $info->getId();
 964
 965                 if ( !isset( $this->allSessionBackends[$id] ) ) {
 966                         if ( !isset( $this->allSessionIds[$id] ) ) {
 967                                 $this->allSessionIds[$id] = new SessionId( $id );
 968                         }
 969                         $backend = new SessionBackend(
 970                                 $this->allSessionIds[$id],
 971                                 $info,
 972                                 $this->store,
 973                                 $this->logger,
 974                                 $this->config->get( 'ObjectCacheSessionExpiry' )
 975                         );
 976                         $this->allSessionBackends[$id] = $backend;
 977                         $delay = $backend->delaySave();
 978                 } else {
 979                         $backend = $this->allSessionBackends[$id];
 980                         $delay = $backend->delaySave();
 981                         if ( $info->wasPersisted() ) {
 982                                 $backend->persist();
 983                         }
 984                         if ( $info->wasRemembered() ) {
 985                                 $backend->setRememberUser( true );
 986                         }
 987                 }
 988
 989                 $request->setSessionId( $backend->getSessionId() );
 990                 $session = $backend->getSession( $request );
 991
 992                 if ( !$info->isIdSafe() ) {
 993                         $session->resetId();
 994                 }
 995
 996                 \ScopedCallback::consume( $delay );
 997                 return $session;
 998         }
 999
1000         /**
1001          * Deregister a SessionBackend
1002          * @private For use from \\MediaWiki\\Session\\SessionBackend only
1003          * @param SessionBackend $backend
1004          */
1005         public function deregisterSessionBackend( SessionBackend $backend ) {
1006                 $id = $backend->getId();
1007                 if ( !isset( $this->allSessionBackends[$id] ) || !isset( $this->allSessionIds[$id] ) ||
1008                         $this->allSessionBackends[$id] !== $backend ||
1009                         $this->allSessionIds[$id] !== $backend->getSessionId()
1010                 ) {
1011                         throw new \InvalidArgumentException( 'Backend was not registered with this SessionManager' );
1012                 }
1013
1014                 unset( $this->allSessionBackends[$id] );
1015                 // Explicitly do not unset $this->allSessionIds[$id]
1016         }
1017
1018         /**
1019          * Change a SessionBackend's ID
1020          * @private For use from \\MediaWiki\\Session\\SessionBackend only
1021          * @param SessionBackend $backend
1022          */
1023         public function changeBackendId( SessionBackend $backend ) {
1024                 $sessionId = $backend->getSessionId();
1025                 $oldId = (string)$sessionId;
1026                 if ( !isset( $this->allSessionBackends[$oldId] ) || !isset( $this->allSessionIds[$oldId] ) ||
1027                         $this->allSessionBackends[$oldId] !== $backend ||
1028                         $this->allSessionIds[$oldId] !== $sessionId
1029                 ) {
1030                         throw new \InvalidArgumentException( 'Backend was not registered with this SessionManager' );
1031                 }
1032
1033                 $newId = $this->generateSessionId();
1034
1035                 unset( $this->allSessionBackends[$oldId], $this->allSessionIds[$oldId] );
1036                 $sessionId->setId( $newId );
1037                 $this->allSessionBackends[$newId] = $backend;
1038                 $this->allSessionIds[$newId] = $sessionId;
1039         }
1040
1041         /**
1042          * Generate a new random session ID
1043          * @return string
1044          */
1045         public function generateSessionId() {
1046                 do {
1047                         $id = wfBaseConvert( \MWCryptRand::generateHex( 40 ), 16, 32, 32 );
1048                         $key = wfMemcKey( 'MWSession', $id );
1049                 } while ( isset( $this->allSessionIds[$id] ) || is_array( $this->store->get( $key ) ) );
1050                 return $id;
1051         }
1052
1053         /**
1054          * Call setters on a PHPSessionHandler
1055          * @private Use PhpSessionHandler::install()
1056          * @param PHPSessionHandler $handler
1057          */
1058         public function setupPHPSessionHandler( PHPSessionHandler $handler ) {
1059                 $handler->setManager( $this, $this->store, $this->logger );
1060         }
1061
1062         /**
1063          * Reset the internal caching for unit testing
1064          */
1065         public static function resetCache() {
1066                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
1067                         // @codeCoverageIgnoreStart
1068                         throw new MWException( __METHOD__ . ' may only be called from unit tests!' );
1069                         // @codeCoverageIgnoreEnd
1070                 }
1071
1072                 self::$globalSession = null;
1073                 self::$globalSessionRequest = null;
1074         }
1075
1076         /**@}*/
1077
1078 }