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[mediawiki.git] / includes / auth / AuthManager.php

<?php
/**
 * Authentication (and possibly Authorization in the future) system 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 Auth
 */

namespace MediaWiki\Auth;

use Config;
use MediaWiki\MediaWikiServices;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Status;
use StatusValue;
use User;
use WebRequest;

/**
 * This serves as the entry point to the authentication system.
 *
 * In the future, it may also serve as the entry point to the authorization
 * system.
 *
 * If you are looking at this because you are working on an extension that creates its own
 * login or signup page, then 1) you really shouldn't do that, 2) if you feel you absolutely
 * have to, subclass AuthManagerSpecialPage or build it on the client side using the clientlogin
 * or the createaccount API. Trying to call this class directly will very likely end up in
 * security vulnerabilities or broken UX in edge cases.
 *
 * If you are working on an extension that needs to integrate with the authentication system
 * (e.g. by providing a new login method, or doing extra permission checks), you'll probably
 * need to write an AuthenticationProvider.
 *
 * If you want to create a "reserved" user programmatically, User::newSystemUser() might be what
 * you are looking for. If you want to change user data, use User::changeAuthenticationData().
 * Code that is related to some SessionProvider or PrimaryAuthenticationProvider can
 * create a (non-reserved) user by calling AuthManager::autoCreateUser(); it is then the provider's
 * responsibility to ensure that the user can authenticate somehow (see especially
 * PrimaryAuthenticationProvider::autoCreatedAccount()).
 * If you are writing code that is not associated with such a provider and needs to create accounts
 * programmatically for real users, you should rethink your architecture. There is no good way to
 * do that as such code has no knowledge of what authentication methods are enabled on the wiki and
 * cannot provide any means for users to access the accounts it would create.
 *
 * The two main control flows when using this class are as follows:
 * * Login, user creation or account linking code will call getAuthenticationRequests(), populate
 *   the requests with data (by using them to build a HTMLForm and have the user fill it, or by
 *   exposing a form specification via the API, so that the client can build it), and pass them to
 *   the appropriate begin* method. That will return either a success/failure response, or more
 *   requests to fill (either by building a form or by redirecting the user to some external
 *   provider which will send the data back), in which case they need to be submitted to the
 *   appropriate continue* method and that step has to be repeated until the response is a success
 *   or failure response. AuthManager will use the session to maintain internal state during the
 *   process.
 * * Code doing an authentication data change will call getAuthenticationRequests(), select
 *   a single request, populate it, and pass it to allowsAuthenticationDataChange() and then
 *   changeAuthenticationData(). If the data change is user-initiated, the whole process needs
 *   to be preceded by a call to securitySensitiveOperationStatus() and aborted if that returns
 *   a non-OK status.
 *
 * @ingroup Auth
 * @since 1.27
 * @see https://www.mediawiki.org/wiki/Manual:SessionManager_and_AuthManager
 */
class AuthManager implements LoggerAwareInterface {
        /** Log in with an existing (not necessarily local) user */
        const ACTION_LOGIN = 'login';
        /** Continue a login process that was interrupted by the need for user input or communication
         * with an external provider */
        const ACTION_LOGIN_CONTINUE = 'login-continue';
        /** Create a new user */
        const ACTION_CREATE = 'create';
        /** Continue a user creation process that was interrupted by the need for user input or
         * communication with an external provider */
        const ACTION_CREATE_CONTINUE = 'create-continue';
        /** Link an existing user to a third-party account */
        const ACTION_LINK = 'link';
        /** Continue a user linking process that was interrupted by the need for user input or
         * communication with an external provider */
        const ACTION_LINK_CONTINUE = 'link-continue';
        /** Change a user's credentials */
        const ACTION_CHANGE = 'change';
        /** Remove a user's credentials */
        const ACTION_REMOVE = 'remove';
        /** Like ACTION_REMOVE but for linking providers only */
        const ACTION_UNLINK = 'unlink';

        /** Security-sensitive operations are ok. */
        const SEC_OK = 'ok';
        /** Security-sensitive operations should re-authenticate. */
        const SEC_REAUTH = 'reauth';
        /** Security-sensitive should not be performed. */
        const SEC_FAIL = 'fail';

        /** Auto-creation is due to SessionManager */
        const AUTOCREATE_SOURCE_SESSION = \MediaWiki\Session\SessionManager::class;

        /** @var AuthManager|null */
        private static $instance = null;

        /** @var WebRequest */
        private $request;

        /** @var Config */
        private $config;

        /** @var LoggerInterface */
        private $logger;

        /** @var AuthenticationProvider[] */
        private $allAuthenticationProviders = [];

        /** @var PreAuthenticationProvider[] */
        private $preAuthenticationProviders = null;

        /** @var PrimaryAuthenticationProvider[] */
        private $primaryAuthenticationProviders = null;

        /** @var SecondaryAuthenticationProvider[] */
        private $secondaryAuthenticationProviders = null;

        /** @var CreatedAccountAuthenticationRequest[] */
        private $createdAccountAuthenticationRequests = [];

        /**
         * Get the global AuthManager
         * @return AuthManager
         */
        public static function singleton() {
                if ( self::$instance === null ) {
                        self::$instance = new self(
                                \RequestContext::getMain()->getRequest(),
                                MediaWikiServices::getInstance()->getMainConfig()
                        );
                }
                return self::$instance;
        }

        /**
         * @param WebRequest $request
         * @param Config $config
         */
        public function __construct( WebRequest $request, Config $config ) {
                $this->request = $request;
                $this->config = $config;
                $this->setLogger( \MediaWiki\Logger\LoggerFactory::getInstance( 'authentication' ) );
        }

        /**
         * @param LoggerInterface $logger
         */
        public function setLogger( LoggerInterface $logger ) {
                $this->logger = $logger;
        }

        /**
         * @return WebRequest
         */
        public function getRequest() {
                return $this->request;
        }

        /**
         * Force certain PrimaryAuthenticationProviders
         * @deprecated For backwards compatibility only
         * @param PrimaryAuthenticationProvider[] $providers
         * @param string $why
         */
        public function forcePrimaryAuthenticationProviders( array $providers, $why ) {
                $this->logger->warning( "Overriding AuthManager primary authn because $why" );

                if ( $this->primaryAuthenticationProviders !== null ) {
                        $this->logger->warning(
                                'PrimaryAuthenticationProviders have already been accessed! I hope nothing breaks.'
                        );

                        $this->allAuthenticationProviders = array_diff_key(
                                $this->allAuthenticationProviders,
                                $this->primaryAuthenticationProviders
                        );
                        $session = $this->request->getSession();
                        $session->remove( 'AuthManager::authnState' );
                        $session->remove( 'AuthManager::accountCreationState' );
                        $session->remove( 'AuthManager::accountLinkState' );
                        $this->createdAccountAuthenticationRequests = [];
                }

                $this->primaryAuthenticationProviders = [];
                foreach ( $providers as $provider ) {
                        if ( !$provider instanceof PrimaryAuthenticationProvider ) {
                                throw new \RuntimeException(
                                        'Expected instance of MediaWiki\\Auth\\PrimaryAuthenticationProvider, got ' .
                                                get_class( $provider )
                                );
                        }
                        $provider->setLogger( $this->logger );
                        $provider->setManager( $this );
                        $provider->setConfig( $this->config );
                        $id = $provider->getUniqueId();
                        if ( isset( $this->allAuthenticationProviders[$id] ) ) {
                                throw new \RuntimeException(
                                        "Duplicate specifications for id $id (classes " .
                                                get_class( $provider ) . ' and ' .
                                                get_class( $this->allAuthenticationProviders[$id] ) . ')'
                                );
                        }
                        $this->allAuthenticationProviders[$id] = $provider;
                        $this->primaryAuthenticationProviders[$id] = $provider;
                }
        }

        /**
         * Call a legacy AuthPlugin method, if necessary
         * @codeCoverageIgnore
         * @deprecated For backwards compatibility only, should be avoided in new code
         * @param string $method AuthPlugin method to call
         * @param array $params Parameters to pass
         * @param mixed $return Return value if AuthPlugin wasn't called
         * @return mixed Return value from the AuthPlugin method, or $return
         */
        public static function callLegacyAuthPlugin( $method, array $params, $return = null ) {
                global $wgAuth;

                if ( $wgAuth && !$wgAuth instanceof AuthManagerAuthPlugin ) {
                        return call_user_func_array( [ $wgAuth, $method ], $params );
                } else {
                        return $return;
                }
        }

        /**
         * @name Authentication
         * @{
         */

        /**
         * Indicate whether user authentication is possible
         *
         * It may not be if the session is provided by something like OAuth
         * for which each individual request includes authentication data.
         *
         * @return bool
         */
        public function canAuthenticateNow() {
                return $this->request->getSession()->canSetUser();
        }

        /**
         * Start an authentication flow
         *
         * In addition to the AuthenticationRequests returned by
         * $this->getAuthenticationRequests(), a client might include a
         * CreateFromLoginAuthenticationRequest from a previous login attempt to
         * preserve state.
         *
         * Instead of the AuthenticationRequests returned by
         * $this->getAuthenticationRequests(), a client might pass a
         * CreatedAccountAuthenticationRequest from an account creation that just
         * succeeded to log in to the just-created account.
         *
         * @param AuthenticationRequest[] $reqs
         * @param string $returnToUrl Url that REDIRECT responses should eventually
         *  return to.
         * @return AuthenticationResponse See self::continueAuthentication()
         */
        public function beginAuthentication( array $reqs, $returnToUrl ) {
                $session = $this->request->getSession();
                if ( !$session->canSetUser() ) {
                        // Caller should have called canAuthenticateNow()
                        $session->remove( 'AuthManager::authnState' );
                        throw new \LogicException( 'Authentication is not possible now' );
                }

                $guessUserName = null;
                foreach ( $reqs as $req ) {
                        $req->returnToUrl = $returnToUrl;
                        // @codeCoverageIgnoreStart
                        if ( $req->username !== null && $req->username !== '' ) {
                                if ( $guessUserName === null ) {
                                        $guessUserName = $req->username;
                                } elseif ( $guessUserName !== $req->username ) {
                                        $guessUserName = null;
                                        break;
                                }
                        }
                        // @codeCoverageIgnoreEnd
                }

                // Check for special-case login of a just-created account
                $req = AuthenticationRequest::getRequestByClass(
                        $reqs, CreatedAccountAuthenticationRequest::class
                );
                if ( $req ) {
                        if ( !in_array( $req, $this->createdAccountAuthenticationRequests, true ) ) {
                                throw new \LogicException(
                                        'CreatedAccountAuthenticationRequests are only valid on ' .
                                                'the same AuthManager that created the account'
                                );
                        }

                        $user = User::newFromName( $req->username );
                        // @codeCoverageIgnoreStart
                        if ( !$user ) {
                                throw new \UnexpectedValueException(
                                        "CreatedAccountAuthenticationRequest had invalid username \"{$req->username}\""
                                );
                        } elseif ( $user->getId() != $req->id ) {
                                throw new \UnexpectedValueException(
                                        "ID for \"{$req->username}\" was {$user->getId()}, expected {$req->id}"
                                );
                        }
                        // @codeCoverageIgnoreEnd

                        $this->logger->info( 'Logging in {user} after account creation', [
                                'user' => $user->getName(),
                        ] );
                        $ret = AuthenticationResponse::newPass( $user->getName() );
                        $this->setSessionDataForUser( $user );
                        $this->callMethodOnProviders( 7, 'postAuthentication', [ $user, $ret ] );
                        $session->remove( 'AuthManager::authnState' );
                        \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $ret, $user, $user->getName() ] );
                        return $ret;
                }

                $this->removeAuthenticationSessionData( null );

                foreach ( $this->getPreAuthenticationProviders() as $provider ) {
                        $status = $provider->testForAuthentication( $reqs );
                        if ( !$status->isGood() ) {
                                $this->logger->debug( 'Login failed in pre-authentication by ' . $provider->getUniqueId() );
                                $ret = AuthenticationResponse::newFail(
                                        Status::wrap( $status )->getMessage()
                                );
                                $this->callMethodOnProviders( 7, 'postAuthentication',
                                        [ User::newFromName( $guessUserName ) ?: null, $ret ]
                                );
                                \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $ret, null, $guessUserName ] );
                                return $ret;
                        }
                }

                $state = [
                        'reqs' => $reqs,
                        'returnToUrl' => $returnToUrl,
                        'guessUserName' => $guessUserName,
                        'primary' => null,
                        'primaryResponse' => null,
                        'secondary' => [],
                        'maybeLink' => [],
                        'continueRequests' => [],
                ];

                // Preserve state from a previous failed login
                $req = AuthenticationRequest::getRequestByClass(
                        $reqs, CreateFromLoginAuthenticationRequest::class
                );
                if ( $req ) {
                        $state['maybeLink'] = $req->maybeLink;
                }

                $session = $this->request->getSession();
                $session->setSecret( 'AuthManager::authnState', $state );
                $session->persist();

                return $this->continueAuthentication( $reqs );
        }

        /**
         * Continue an authentication flow
         *
         * Return values are interpreted as follows:
         * - status FAIL: Authentication failed. If $response->createRequest is
         *   set, that may be passed to self::beginAuthentication() or to
         *   self::beginAccountCreation() to preserve state.
         * - status REDIRECT: The client should be redirected to the contained URL,
         *   new AuthenticationRequests should be made (if any), then
         *   AuthManager::continueAuthentication() should be called.
         * - status UI: The client should be presented with a user interface for
         *   the fields in the specified AuthenticationRequests, then new
         *   AuthenticationRequests should be made, then
         *   AuthManager::continueAuthentication() should be called.
         * - status RESTART: The user logged in successfully with a third-party
         *   service, but the third-party credentials aren't attached to any local
         *   account. This could be treated as a UI or a FAIL.
         * - status PASS: Authentication was successful.
         *
         * @param AuthenticationRequest[] $reqs
         * @return AuthenticationResponse
         */
        public function continueAuthentication( array $reqs ) {
                $session = $this->request->getSession();
                try {
                        if ( !$session->canSetUser() ) {
                                // Caller should have called canAuthenticateNow()
                                // @codeCoverageIgnoreStart
                                throw new \LogicException( 'Authentication is not possible now' );
                                // @codeCoverageIgnoreEnd
                        }

                        $state = $session->getSecret( 'AuthManager::authnState' );
                        if ( !is_array( $state ) ) {
                                return AuthenticationResponse::newFail(
                                        wfMessage( 'authmanager-authn-not-in-progress' )
                                );
                        }
                        $state['continueRequests'] = [];

                        $guessUserName = $state['guessUserName'];

                        foreach ( $reqs as $req ) {
                                $req->returnToUrl = $state['returnToUrl'];
                        }

                        // Step 1: Choose an primary authentication provider, and call it until it succeeds.

                        if ( $state['primary'] === null ) {
                                // We haven't picked a PrimaryAuthenticationProvider yet
                                // @codeCoverageIgnoreStart
                                $guessUserName = null;
                                foreach ( $reqs as $req ) {
                                        if ( $req->username !== null && $req->username !== '' ) {
                                                if ( $guessUserName === null ) {
                                                        $guessUserName = $req->username;
                                                } elseif ( $guessUserName !== $req->username ) {
                                                        $guessUserName = null;
                                                        break;
                                                }
                                        }
                                }
                                $state['guessUserName'] = $guessUserName;
                                // @codeCoverageIgnoreEnd
                                $state['reqs'] = $reqs;

                                foreach ( $this->getPrimaryAuthenticationProviders() as $id => $provider ) {
                                        $res = $provider->beginPrimaryAuthentication( $reqs );
                                        switch ( $res->status ) {
                                                case AuthenticationResponse::PASS;
                                                        $state['primary'] = $id;
                                                        $state['primaryResponse'] = $res;
                                                        $this->logger->debug( "Primary login with $id succeeded" );
                                                        break 2;
                                                case AuthenticationResponse::FAIL;
                                                        $this->logger->debug( "Login failed in primary authentication by $id" );
                                                        if ( $res->createRequest || $state['maybeLink'] ) {
                                                                $res->createRequest = new CreateFromLoginAuthenticationRequest(
                                                                        $res->createRequest, $state['maybeLink']
                                                                );
                                                        }
                                                        $this->callMethodOnProviders( 7, 'postAuthentication',
                                                                [ User::newFromName( $guessUserName ) ?: null, $res ]
                                                        );
                                                        $session->remove( 'AuthManager::authnState' );
                                                        \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $res, null, $guessUserName ] );
                                                        return $res;
                                                case AuthenticationResponse::ABSTAIN;
                                                        // Continue loop
                                                        break;
                                                case AuthenticationResponse::REDIRECT;
                                                case AuthenticationResponse::UI;
                                                        $this->logger->debug( "Primary login with $id returned $res->status" );
                                                        $this->fillRequests( $res->neededRequests, self::ACTION_LOGIN, $guessUserName );
                                                        $state['primary'] = $id;
                                                        $state['continueRequests'] = $res->neededRequests;
                                                        $session->setSecret( 'AuthManager::authnState', $state );
                                                        return $res;

                                                        // @codeCoverageIgnoreStart
                                                default:
                                                        throw new \DomainException(
                                                                get_class( $provider ) . "::beginPrimaryAuthentication() returned $res->status"
                                                        );
                                                        // @codeCoverageIgnoreEnd
                                        }
                                }
                                if ( $state['primary'] === null ) {
                                        $this->logger->debug( 'Login failed in primary authentication because no provider accepted' );
                                        $ret = AuthenticationResponse::newFail(
                                                wfMessage( 'authmanager-authn-no-primary' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAuthentication',
                                                [ User::newFromName( $guessUserName ) ?: null, $ret ]
                                        );
                                        $session->remove( 'AuthManager::authnState' );
                                        return $ret;
                                }
                        } elseif ( $state['primaryResponse'] === null ) {
                                $provider = $this->getAuthenticationProvider( $state['primary'] );
                                if ( !$provider instanceof PrimaryAuthenticationProvider ) {
                                        // Configuration changed? Force them to start over.
                                        // @codeCoverageIgnoreStart
                                        $ret = AuthenticationResponse::newFail(
                                                wfMessage( 'authmanager-authn-not-in-progress' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAuthentication',
                                                [ User::newFromName( $guessUserName ) ?: null, $ret ]
                                        );
                                        $session->remove( 'AuthManager::authnState' );
                                        return $ret;
                                        // @codeCoverageIgnoreEnd
                                }
                                $id = $provider->getUniqueId();
                                $res = $provider->continuePrimaryAuthentication( $reqs );
                                switch ( $res->status ) {
                                        case AuthenticationResponse::PASS;
                                                $state['primaryResponse'] = $res;
                                                $this->logger->debug( "Primary login with $id succeeded" );
                                                break;
                                        case AuthenticationResponse::FAIL;
                                                $this->logger->debug( "Login failed in primary authentication by $id" );
                                                if ( $res->createRequest || $state['maybeLink'] ) {
                                                        $res->createRequest = new CreateFromLoginAuthenticationRequest(
                                                                $res->createRequest, $state['maybeLink']
                                                        );
                                                }
                                                $this->callMethodOnProviders( 7, 'postAuthentication',
                                                        [ User::newFromName( $guessUserName ) ?: null, $res ]
                                                );
                                                $session->remove( 'AuthManager::authnState' );
                                                \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $res, null, $guessUserName ] );
                                                return $res;
                                        case AuthenticationResponse::REDIRECT;
                                        case AuthenticationResponse::UI;
                                                $this->logger->debug( "Primary login with $id returned $res->status" );
                                                $this->fillRequests( $res->neededRequests, self::ACTION_LOGIN, $guessUserName );
                                                $state['continueRequests'] = $res->neededRequests;
                                                $session->setSecret( 'AuthManager::authnState', $state );
                                                return $res;
                                        default:
                                                throw new \DomainException(
                                                        get_class( $provider ) . "::continuePrimaryAuthentication() returned $res->status"
                                                );
                                }
                        }

                        $res = $state['primaryResponse'];
                        if ( $res->username === null ) {
                                $provider = $this->getAuthenticationProvider( $state['primary'] );
                                if ( !$provider instanceof PrimaryAuthenticationProvider ) {
                                        // Configuration changed? Force them to start over.
                                        // @codeCoverageIgnoreStart
                                        $ret = AuthenticationResponse::newFail(
                                                wfMessage( 'authmanager-authn-not-in-progress' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAuthentication',
                                                [ User::newFromName( $guessUserName ) ?: null, $ret ]
                                        );
                                        $session->remove( 'AuthManager::authnState' );
                                        return $ret;
                                        // @codeCoverageIgnoreEnd
                                }

                                if ( $provider->accountCreationType() === PrimaryAuthenticationProvider::TYPE_LINK &&
                                        $res->linkRequest &&
                                         // don't confuse the user with an incorrect message if linking is disabled
                                        $this->getAuthenticationProvider( ConfirmLinkSecondaryAuthenticationProvider::class )
                                ) {
                                        $state['maybeLink'][$res->linkRequest->getUniqueId()] = $res->linkRequest;
                                        $msg = 'authmanager-authn-no-local-user-link';
                                } else {
                                        $msg = 'authmanager-authn-no-local-user';
                                }
                                $this->logger->debug(
                                        "Primary login with {$provider->getUniqueId()} succeeded, but returned no user"
                                );
                                $ret = AuthenticationResponse::newRestart( wfMessage( $msg ) );
                                $ret->neededRequests = $this->getAuthenticationRequestsInternal(
                                        self::ACTION_LOGIN,
                                        [],
                                        $this->getPrimaryAuthenticationProviders() + $this->getSecondaryAuthenticationProviders()
                                );
                                if ( $res->createRequest || $state['maybeLink'] ) {
                                        $ret->createRequest = new CreateFromLoginAuthenticationRequest(
                                                $res->createRequest, $state['maybeLink']
                                        );
                                        $ret->neededRequests[] = $ret->createRequest;
                                }
                                $this->fillRequests( $ret->neededRequests, self::ACTION_LOGIN, null, true );
                                $session->setSecret( 'AuthManager::authnState', [
                                        'reqs' => [], // Will be filled in later
                                        'primary' => null,
                                        'primaryResponse' => null,
                                        'secondary' => [],
                                        'continueRequests' => $ret->neededRequests,
                                ] + $state );
                                return $ret;
                        }

                        // Step 2: Primary authentication succeeded, create the User object
                        // (and add the user locally if necessary)

                        $user = User::newFromName( $res->username, 'usable' );
                        if ( !$user ) {
                                $provider = $this->getAuthenticationProvider( $state['primary'] );
                                throw new \DomainException(
                                        get_class( $provider ) . " returned an invalid username: {$res->username}"
                                );
                        }
                        if ( $user->getId() === 0 ) {
                                // User doesn't exist locally. Create it.
                                $this->logger->info( 'Auto-creating {user} on login', [
                                        'user' => $user->getName(),
                                ] );
                                $status = $this->autoCreateUser( $user, $state['primary'], false );
                                if ( !$status->isGood() ) {
                                        $ret = AuthenticationResponse::newFail(
                                                Status::wrap( $status )->getMessage( 'authmanager-authn-autocreate-failed' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAuthentication', [ $user, $ret ] );
                                        $session->remove( 'AuthManager::authnState' );
                                        \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $ret, $user, $user->getName() ] );
                                        return $ret;
                                }
                        }

                        // Step 3: Iterate over all the secondary authentication providers.

                        $beginReqs = $state['reqs'];

                        foreach ( $this->getSecondaryAuthenticationProviders() as $id => $provider ) {
                                if ( !isset( $state['secondary'][$id] ) ) {
                                        // This provider isn't started yet, so we pass it the set
                                        // of reqs from beginAuthentication instead of whatever
                                        // might have been used by a previous provider in line.
                                        $func = 'beginSecondaryAuthentication';
                                        $res = $provider->beginSecondaryAuthentication( $user, $beginReqs );
                                } elseif ( !$state['secondary'][$id] ) {
                                        $func = 'continueSecondaryAuthentication';
                                        $res = $provider->continueSecondaryAuthentication( $user, $reqs );
                                } else {
                                        continue;
                                }
                                switch ( $res->status ) {
                                        case AuthenticationResponse::PASS;
                                                $this->logger->debug( "Secondary login with $id succeeded" );
                                                // fall through
                                        case AuthenticationResponse::ABSTAIN;
                                                $state['secondary'][$id] = true;
                                                break;
                                        case AuthenticationResponse::FAIL;
                                                $this->logger->debug( "Login failed in secondary authentication by $id" );
                                                $this->callMethodOnProviders( 7, 'postAuthentication', [ $user, $res ] );
                                                $session->remove( 'AuthManager::authnState' );
                                                \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $res, $user, $user->getName() ] );
                                                return $res;
                                        case AuthenticationResponse::REDIRECT;
                                        case AuthenticationResponse::UI;
                                                $this->logger->debug( "Secondary login with $id returned " . $res->status );
                                                $this->fillRequests( $res->neededRequests, self::ACTION_LOGIN, $user->getName() );
                                                $state['secondary'][$id] = false;
                                                $state['continueRequests'] = $res->neededRequests;
                                                $session->setSecret( 'AuthManager::authnState', $state );
                                                return $res;

                                                // @codeCoverageIgnoreStart
                                        default:
                                                throw new \DomainException(
                                                        get_class( $provider ) . "::{$func}() returned $res->status"
                                                );
                                                // @codeCoverageIgnoreEnd
                                }
                        }

                        // Step 4: Authentication complete! Set the user in the session and
                        // clean up.

                        $this->logger->info( 'Login for {user} succeeded', [
                                'user' => $user->getName(),
                        ] );
                        /** @var RememberMeAuthenticationRequest $req */
                        $req = AuthenticationRequest::getRequestByClass(
                                $beginReqs, RememberMeAuthenticationRequest::class
                        );
                        $this->setSessionDataForUser( $user, $req && $req->rememberMe );
                        $ret = AuthenticationResponse::newPass( $user->getName() );
                        $this->callMethodOnProviders( 7, 'postAuthentication', [ $user, $ret ] );
                        $session->remove( 'AuthManager::authnState' );
                        $this->removeAuthenticationSessionData( null );
                        \Hooks::run( 'AuthManagerLoginAuthenticateAudit', [ $ret, $user, $user->getName() ] );
                        return $ret;
                } catch ( \Exception $ex ) {
                        $session->remove( 'AuthManager::authnState' );
                        throw $ex;
                }
        }

        /**
         * Whether security-sensitive operations should proceed.
         *
         * A "security-sensitive operation" is something like a password or email
         * change, that would normally have a "reenter your password to confirm"
         * box if we only supported password-based authentication.
         *
         * @param string $operation Operation being checked. This should be a
         *  message-key-like string such as 'change-password' or 'change-email'.
         * @return string One of the SEC_* constants.
         */
        public function securitySensitiveOperationStatus( $operation ) {
                $status = self::SEC_OK;

                $this->logger->debug( __METHOD__ . ": Checking $operation" );

                $session = $this->request->getSession();
                $aId = $session->getUser()->getId();
                if ( $aId === 0 ) {
                        // User isn't authenticated. DWIM?
                        $status = $this->canAuthenticateNow() ? self::SEC_REAUTH : self::SEC_FAIL;
                        $this->logger->info( __METHOD__ . ": Not logged in! $operation is $status" );
                        return $status;
                }

                if ( $session->canSetUser() ) {
                        $id = $session->get( 'AuthManager:lastAuthId' );
                        $last = $session->get( 'AuthManager:lastAuthTimestamp' );
                        if ( $id !== $aId || $last === null ) {
                                $timeSinceLogin = PHP_INT_MAX; // Forever ago
                        } else {
                                $timeSinceLogin = max( 0, time() - $last );
                        }

                        $thresholds = $this->config->get( 'ReauthenticateTime' );
                        if ( isset( $thresholds[$operation] ) ) {
                                $threshold = $thresholds[$operation];
                        } elseif ( isset( $thresholds['default'] ) ) {
                                $threshold = $thresholds['default'];
                        } else {
                                throw new \UnexpectedValueException( '$wgReauthenticateTime lacks a default' );
                        }

                        if ( $threshold >= 0 && $timeSinceLogin > $threshold ) {
                                $status = self::SEC_REAUTH;
                        }
                } else {
                        $timeSinceLogin = -1;

                        $pass = $this->config->get( 'AllowSecuritySensitiveOperationIfCannotReauthenticate' );
                        if ( isset( $pass[$operation] ) ) {
                                $status = $pass[$operation] ? self::SEC_OK : self::SEC_FAIL;
                        } elseif ( isset( $pass['default'] ) ) {
                                $status = $pass['default'] ? self::SEC_OK : self::SEC_FAIL;
                        } else {
                                throw new \UnexpectedValueException(
                                        '$wgAllowSecuritySensitiveOperationIfCannotReauthenticate lacks a default'
                                );
                        }
                }

                \Hooks::run( 'SecuritySensitiveOperationStatus', [
                        &$status, $operation, $session, $timeSinceLogin
                ] );

                // If authentication is not possible, downgrade from "REAUTH" to "FAIL".
                if ( !$this->canAuthenticateNow() && $status === self::SEC_REAUTH ) {
                        $status = self::SEC_FAIL;
                }

                $this->logger->info( __METHOD__ . ": $operation is $status" );

                return $status;
        }

        /**
         * Determine whether a username can authenticate
         *
         * This is mainly for internal purposes and only takes authentication data into account,
         * not things like blocks that can change without the authentication system being aware.
         *
         * @param string $username MediaWiki username
         * @return bool
         */
        public function userCanAuthenticate( $username ) {
                foreach ( $this->getPrimaryAuthenticationProviders() as $provider ) {
                        if ( $provider->testUserCanAuthenticate( $username ) ) {
                                return true;
                        }
                }
                return false;
        }

        /**
         * Provide normalized versions of the username for security checks
         *
         * Since different providers can normalize the input in different ways,
         * this returns an array of all the different ways the name might be
         * normalized for authentication.
         *
         * The returned strings should not be revealed to the user, as that might
         * leak private information (e.g. an email address might be normalized to a
         * username).
         *
         * @param string $username
         * @return string[]
         */
        public function normalizeUsername( $username ) {
                $ret = [];
                foreach ( $this->getPrimaryAuthenticationProviders() as $provider ) {
                        $normalized = $provider->providerNormalizeUsername( $username );
                        if ( $normalized !== null ) {
                                $ret[$normalized] = true;
                        }
                }
                return array_keys( $ret );
        }

        /**@}*/

        /**
         * @name Authentication data changing
         * @{
         */

        /**
         * Revoke any authentication credentials for a user
         *
         * After this, the user should no longer be able to log in.
         *
         * @param string $username
         */
        public function revokeAccessForUser( $username ) {
                $this->logger->info( 'Revoking access for {user}', [
                        'user' => $username,
                ] );
                $this->callMethodOnProviders( 6, 'providerRevokeAccessForUser', [ $username ] );
        }

        /**
         * Validate a change of authentication data (e.g. passwords)
         * @param AuthenticationRequest $req
         * @param bool $checkData If false, $req hasn't been loaded from the
         *  submission so checks on user-submitted fields should be skipped. $req->username is
         *  considered user-submitted for this purpose, even if it cannot be changed via
         *  $req->loadFromSubmission.
         * @return Status
         */
        public function allowsAuthenticationDataChange( AuthenticationRequest $req, $checkData = true ) {
                $any = false;
                $providers = $this->getPrimaryAuthenticationProviders() +
                        $this->getSecondaryAuthenticationProviders();
                foreach ( $providers as $provider ) {
                        $status = $provider->providerAllowsAuthenticationDataChange( $req, $checkData );
                        if ( !$status->isGood() ) {
                                return Status::wrap( $status );
                        }
                        $any = $any || $status->value !== 'ignored';
                }
                if ( !$any ) {
                        $status = Status::newGood( 'ignored' );
                        $status->warning( 'authmanager-change-not-supported' );
                        return $status;
                }
                return Status::newGood();
        }

        /**
         * Change authentication data (e.g. passwords)
         *
         * If $req was returned for AuthManager::ACTION_CHANGE, using $req should
         * result in a successful login in the future.
         *
         * If $req was returned for AuthManager::ACTION_REMOVE, using $req should
         * no longer result in a successful login.
         *
         * This method should only be called if allowsAuthenticationDataChange( $req, true )
         * returned success.
         *
         * @param AuthenticationRequest $req
         */
        public function changeAuthenticationData( AuthenticationRequest $req ) {
                $this->logger->info( 'Changing authentication data for {user} class {what}', [
                        'user' => is_string( $req->username ) ? $req->username : '<no name>',
                        'what' => get_class( $req ),
                ] );

                $this->callMethodOnProviders( 6, 'providerChangeAuthenticationData', [ $req ] );

                // When the main account's authentication data is changed, invalidate
                // all BotPasswords too.
                \BotPassword::invalidateAllPasswordsForUser( $req->username );
        }

        /**@}*/

        /**
         * @name Account creation
         * @{
         */

        /**
         * Determine whether accounts can be created
         * @return bool
         */
        public function canCreateAccounts() {
                foreach ( $this->getPrimaryAuthenticationProviders() as $provider ) {
                        switch ( $provider->accountCreationType() ) {
                                case PrimaryAuthenticationProvider::TYPE_CREATE:
                                case PrimaryAuthenticationProvider::TYPE_LINK:
                                        return true;
                        }
                }
                return false;
        }

        /**
         * Determine whether a particular account can be created
         * @param string $username MediaWiki username
         * @param array $options
         *  - flags: (int) Bitfield of User:READ_* constants, default User::READ_NORMAL
         *  - creating: (bool) For internal use only. Never specify this.
         * @return Status
         */
        public function canCreateAccount( $username, $options = [] ) {
                // Back compat
                if ( is_int( $options ) ) {
                        $options = [ 'flags' => $options ];
                }
                $options += [
                        'flags' => User::READ_NORMAL,
                        'creating' => false,
                ];
                $flags = $options['flags'];

                if ( !$this->canCreateAccounts() ) {
                        return Status::newFatal( 'authmanager-create-disabled' );
                }

                if ( $this->userExists( $username, $flags ) ) {
                        return Status::newFatal( 'userexists' );
                }

                $user = User::newFromName( $username, 'creatable' );
                if ( !is_object( $user ) ) {
                        return Status::newFatal( 'noname' );
                } else {
                        $user->load( $flags ); // Explicitly load with $flags, auto-loading always uses READ_NORMAL
                        if ( $user->getId() !== 0 ) {
                                return Status::newFatal( 'userexists' );
                        }
                }

                // Denied by providers?
                $providers = $this->getPreAuthenticationProviders() +
                        $this->getPrimaryAuthenticationProviders() +
                        $this->getSecondaryAuthenticationProviders();
                foreach ( $providers as $provider ) {
                        $status = $provider->testUserForCreation( $user, false, $options );
                        if ( !$status->isGood() ) {
                                return Status::wrap( $status );
                        }
                }

                return Status::newGood();
        }

        /**
         * Basic permissions checks on whether a user can create accounts
         * @param User $creator User doing the account creation
         * @return Status
         */
        public function checkAccountCreatePermissions( User $creator ) {
                // Wiki is read-only?
                if ( wfReadOnly() ) {
                        return Status::newFatal( 'readonlytext', wfReadOnlyReason() );
                }

                // This is awful, this permission check really shouldn't go through Title.
                $permErrors = \SpecialPage::getTitleFor( 'CreateAccount' )
                        ->getUserPermissionsErrors( 'createaccount', $creator, 'secure' );
                if ( $permErrors ) {
                        $status = Status::newGood();
                        foreach ( $permErrors as $args ) {
                                call_user_func_array( [ $status, 'fatal' ], $args );
                        }
                        return $status;
                }

                $block = $creator->isBlockedFromCreateAccount();
                if ( $block ) {
                        $errorParams = [
                                $block->getTarget(),
                                $block->mReason ?: wfMessage( 'blockednoreason' )->text(),
                                $block->getByName()
                        ];

                        if ( $block->getType() === \Block::TYPE_RANGE ) {
                                $errorMessage = 'cantcreateaccount-range-text';
                                $errorParams[] = $this->getRequest()->getIP();
                        } else {
                                $errorMessage = 'cantcreateaccount-text';
                        }

                        return Status::newFatal( wfMessage( $errorMessage, $errorParams ) );
                }

                $ip = $this->getRequest()->getIP();
                if ( $creator->isDnsBlacklisted( $ip, true /* check $wgProxyWhitelist */ ) ) {
                        return Status::newFatal( 'sorbs_create_account_reason' );
                }

                return Status::newGood();
        }

        /**
         * Start an account creation flow
         *
         * In addition to the AuthenticationRequests returned by
         * $this->getAuthenticationRequests(), a client might include a
         * CreateFromLoginAuthenticationRequest from a previous login attempt. If
         * <code>
         * $createFromLoginAuthenticationRequest->hasPrimaryStateForAction( AuthManager::ACTION_CREATE )
         * </code>
         * returns true, any AuthenticationRequest::PRIMARY_REQUIRED requests
         * should be omitted. If the CreateFromLoginAuthenticationRequest has a
         * username set, that username must be used for all other requests.
         *
         * @param User $creator User doing the account creation
         * @param AuthenticationRequest[] $reqs
         * @param string $returnToUrl Url that REDIRECT responses should eventually
         *  return to.
         * @return AuthenticationResponse
         */
        public function beginAccountCreation( User $creator, array $reqs, $returnToUrl ) {
                $session = $this->request->getSession();
                if ( !$this->canCreateAccounts() ) {
                        // Caller should have called canCreateAccounts()
                        $session->remove( 'AuthManager::accountCreationState' );
                        throw new \LogicException( 'Account creation is not possible' );
                }

                try {
                        $username = AuthenticationRequest::getUsernameFromRequests( $reqs );
                } catch ( \UnexpectedValueException $ex ) {
                        $username = null;
                }
                if ( $username === null ) {
                        $this->logger->debug( __METHOD__ . ': No username provided' );
                        return AuthenticationResponse::newFail( wfMessage( 'noname' ) );
                }

                // Permissions check
                $status = $this->checkAccountCreatePermissions( $creator );
                if ( !$status->isGood() ) {
                        $this->logger->debug( __METHOD__ . ': {creator} cannot create users: {reason}', [
                                'user' => $username,
                                'creator' => $creator->getName(),
                                'reason' => $status->getWikiText( null, null, 'en' )
                        ] );
                        return AuthenticationResponse::newFail( $status->getMessage() );
                }

                $status = $this->canCreateAccount(
                        $username, [ 'flags' => User::READ_LOCKING, 'creating' => true ]
                );
                if ( !$status->isGood() ) {
                        $this->logger->debug( __METHOD__ . ': {user} cannot be created: {reason}', [
                                'user' => $username,
                                'creator' => $creator->getName(),
                                'reason' => $status->getWikiText( null, null, 'en' )
                        ] );
                        return AuthenticationResponse::newFail( $status->getMessage() );
                }

                $user = User::newFromName( $username, 'creatable' );
                foreach ( $reqs as $req ) {
                        $req->username = $username;
                        $req->returnToUrl = $returnToUrl;
                        if ( $req instanceof UserDataAuthenticationRequest ) {
                                $status = $req->populateUser( $user );
                                if ( !$status->isGood() ) {
                                        $status = Status::wrap( $status );
                                        $session->remove( 'AuthManager::accountCreationState' );
                                        $this->logger->debug( __METHOD__ . ': UserData is invalid: {reason}', [
                                                'user' => $user->getName(),
                                                'creator' => $creator->getName(),
                                                'reason' => $status->getWikiText( null, null, 'en' ),
                                        ] );
                                        return AuthenticationResponse::newFail( $status->getMessage() );
                                }
                        }
                }

                $this->removeAuthenticationSessionData( null );

                $state = [
                        'username' => $username,
                        'userid' => 0,
                        'creatorid' => $creator->getId(),
                        'creatorname' => $creator->getName(),
                        'reqs' => $reqs,
                        'returnToUrl' => $returnToUrl,
                        'primary' => null,
                        'primaryResponse' => null,
                        'secondary' => [],
                        'continueRequests' => [],
                        'maybeLink' => [],
                        'ranPreTests' => false,
                ];

                // Special case: converting a login to an account creation
                $req = AuthenticationRequest::getRequestByClass(
                        $reqs, CreateFromLoginAuthenticationRequest::class
                );
                if ( $req ) {
                        $state['maybeLink'] = $req->maybeLink;

                        if ( $req->createRequest ) {
                                $reqs[] = $req->createRequest;
                                $state['reqs'][] = $req->createRequest;
                        }
                }

                $session->setSecret( 'AuthManager::accountCreationState', $state );
                $session->persist();

                return $this->continueAccountCreation( $reqs );
        }

        /**
         * Continue an account creation flow
         * @param AuthenticationRequest[] $reqs
         * @return AuthenticationResponse
         */
        public function continueAccountCreation( array $reqs ) {
                $session = $this->request->getSession();
                try {
                        if ( !$this->canCreateAccounts() ) {
                                // Caller should have called canCreateAccounts()
                                $session->remove( 'AuthManager::accountCreationState' );
                                throw new \LogicException( 'Account creation is not possible' );
                        }

                        $state = $session->getSecret( 'AuthManager::accountCreationState' );
                        if ( !is_array( $state ) ) {
                                return AuthenticationResponse::newFail(
                                        wfMessage( 'authmanager-create-not-in-progress' )
                                );
                        }
                        $state['continueRequests'] = [];

                        // Step 0: Prepare and validate the input

                        $user = User::newFromName( $state['username'], 'creatable' );
                        if ( !is_object( $user ) ) {
                                $session->remove( 'AuthManager::accountCreationState' );
                                $this->logger->debug( __METHOD__ . ': Invalid username', [
                                        'user' => $state['username'],
                                ] );
                                return AuthenticationResponse::newFail( wfMessage( 'noname' ) );
                        }

                        if ( $state['creatorid'] ) {
                                $creator = User::newFromId( $state['creatorid'] );
                        } else {
                                $creator = new User;
                                $creator->setName( $state['creatorname'] );
                        }

                        // Avoid account creation races on double submissions
                        $cache = \ObjectCache::getLocalClusterInstance();
                        $lock = $cache->getScopedLock( $cache->makeGlobalKey( 'account', md5( $user->getName() ) ) );
                        if ( !$lock ) {
                                // Don't clear AuthManager::accountCreationState for this code
                                // path because the process that won the race owns it.
                                $this->logger->debug( __METHOD__ . ': Could not acquire account creation lock', [
                                        'user' => $user->getName(),
                                        'creator' => $creator->getName(),
                                ] );
                                return AuthenticationResponse::newFail( wfMessage( 'usernameinprogress' ) );
                        }

                        // Permissions check
                        $status = $this->checkAccountCreatePermissions( $creator );
                        if ( !$status->isGood() ) {
                                $this->logger->debug( __METHOD__ . ': {creator} cannot create users: {reason}', [
                                        'user' => $user->getName(),
                                        'creator' => $creator->getName(),
                                        'reason' => $status->getWikiText( null, null, 'en' )
                                ] );
                                $ret = AuthenticationResponse::newFail( $status->getMessage() );
                                $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                $session->remove( 'AuthManager::accountCreationState' );
                                return $ret;
                        }

                        // Load from master for existence check
                        $user->load( User::READ_LOCKING );

                        if ( $state['userid'] === 0 ) {
                                if ( $user->getId() != 0 ) {
                                        $this->logger->debug( __METHOD__ . ': User exists locally', [
                                                'user' => $user->getName(),
                                                'creator' => $creator->getName(),
                                        ] );
                                        $ret = AuthenticationResponse::newFail( wfMessage( 'userexists' ) );
                                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                        $session->remove( 'AuthManager::accountCreationState' );
                                        return $ret;
                                }
                        } else {
                                if ( $user->getId() == 0 ) {
                                        $this->logger->debug( __METHOD__ . ': User does not exist locally when it should', [
                                                'user' => $user->getName(),
                                                'creator' => $creator->getName(),
                                                'expected_id' => $state['userid'],
                                        ] );
                                        throw new \UnexpectedValueException(
                                                "User \"{$state['username']}\" should exist now, but doesn't!"
                                        );
                                }
                                if ( $user->getId() != $state['userid'] ) {
                                        $this->logger->debug( __METHOD__ . ': User ID/name mismatch', [
                                                'user' => $user->getName(),
                                                'creator' => $creator->getName(),
                                                'expected_id' => $state['userid'],
                                                'actual_id' => $user->getId(),
                                        ] );
                                        throw new \UnexpectedValueException(
                                                "User \"{$state['username']}\" exists, but " .
                                                        "ID {$user->getId()} != {$state['userid']}!"
                                        );
                                }
                        }
                        foreach ( $state['reqs'] as $req ) {
                                if ( $req instanceof UserDataAuthenticationRequest ) {
                                        $status = $req->populateUser( $user );
                                        if ( !$status->isGood() ) {
                                                // This should never happen...
                                                $status = Status::wrap( $status );
                                                $this->logger->debug( __METHOD__ . ': UserData is invalid: {reason}', [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                        'reason' => $status->getWikiText( null, null, 'en' ),
                                                ] );
                                                $ret = AuthenticationResponse::newFail( $status->getMessage() );
                                                $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                                $session->remove( 'AuthManager::accountCreationState' );
                                                return $ret;
                                        }
                                }
                        }

                        foreach ( $reqs as $req ) {
                                $req->returnToUrl = $state['returnToUrl'];
                                $req->username = $state['username'];
                        }

                        // Run pre-creation tests, if we haven't already
                        if ( !$state['ranPreTests'] ) {
                                $providers = $this->getPreAuthenticationProviders() +
                                        $this->getPrimaryAuthenticationProviders() +
                                        $this->getSecondaryAuthenticationProviders();
                                foreach ( $providers as $id => $provider ) {
                                        $status = $provider->testForAccountCreation( $user, $creator, $reqs );
                                        if ( !$status->isGood() ) {
                                                $this->logger->debug( __METHOD__ . ": Fail in pre-authentication by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                $ret = AuthenticationResponse::newFail(
                                                        Status::wrap( $status )->getMessage()
                                                );
                                                $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                                $session->remove( 'AuthManager::accountCreationState' );
                                                return $ret;
                                        }
                                }

                                $state['ranPreTests'] = true;
                        }

                        // Step 1: Choose a primary authentication provider and call it until it succeeds.

                        if ( $state['primary'] === null ) {
                                // We haven't picked a PrimaryAuthenticationProvider yet
                                foreach ( $this->getPrimaryAuthenticationProviders() as $id => $provider ) {
                                        if ( $provider->accountCreationType() === PrimaryAuthenticationProvider::TYPE_NONE ) {
                                                continue;
                                        }
                                        $res = $provider->beginPrimaryAccountCreation( $user, $creator, $reqs );
                                        switch ( $res->status ) {
                                                case AuthenticationResponse::PASS;
                                                        $this->logger->debug( __METHOD__ . ": Primary creation passed by $id", [
                                                                'user' => $user->getName(),
                                                                'creator' => $creator->getName(),
                                                        ] );
                                                        $state['primary'] = $id;
                                                        $state['primaryResponse'] = $res;
                                                        break 2;
                                                case AuthenticationResponse::FAIL;
                                                        $this->logger->debug( __METHOD__ . ": Primary creation failed by $id", [
                                                                'user' => $user->getName(),
                                                                'creator' => $creator->getName(),
                                                        ] );
                                                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $res ] );
                                                        $session->remove( 'AuthManager::accountCreationState' );
                                                        return $res;
                                                case AuthenticationResponse::ABSTAIN;
                                                        // Continue loop
                                                        break;
                                                case AuthenticationResponse::REDIRECT;
                                                case AuthenticationResponse::UI;
                                                        $this->logger->debug( __METHOD__ . ": Primary creation $res->status by $id", [
                                                                'user' => $user->getName(),
                                                                'creator' => $creator->getName(),
                                                        ] );
                                                        $this->fillRequests( $res->neededRequests, self::ACTION_CREATE, null );
                                                        $state['primary'] = $id;
                                                        $state['continueRequests'] = $res->neededRequests;
                                                        $session->setSecret( 'AuthManager::accountCreationState', $state );
                                                        return $res;

                                                        // @codeCoverageIgnoreStart
                                                default:
                                                        throw new \DomainException(
                                                                get_class( $provider ) . "::beginPrimaryAccountCreation() returned $res->status"
                                                        );
                                                        // @codeCoverageIgnoreEnd
                                        }
                                }
                                if ( $state['primary'] === null ) {
                                        $this->logger->debug( __METHOD__ . ': Primary creation failed because no provider accepted', [
                                                'user' => $user->getName(),
                                                'creator' => $creator->getName(),
                                        ] );
                                        $ret = AuthenticationResponse::newFail(
                                                wfMessage( 'authmanager-create-no-primary' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                        $session->remove( 'AuthManager::accountCreationState' );
                                        return $ret;
                                }
                        } elseif ( $state['primaryResponse'] === null ) {
                                $provider = $this->getAuthenticationProvider( $state['primary'] );
                                if ( !$provider instanceof PrimaryAuthenticationProvider ) {
                                        // Configuration changed? Force them to start over.
                                        // @codeCoverageIgnoreStart
                                        $ret = AuthenticationResponse::newFail(
                                                wfMessage( 'authmanager-create-not-in-progress' )
                                        );
                                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                        $session->remove( 'AuthManager::accountCreationState' );
                                        return $ret;
                                        // @codeCoverageIgnoreEnd
                                }
                                $id = $provider->getUniqueId();
                                $res = $provider->continuePrimaryAccountCreation( $user, $creator, $reqs );
                                switch ( $res->status ) {
                                        case AuthenticationResponse::PASS;
                                                $this->logger->debug( __METHOD__ . ": Primary creation passed by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                $state['primaryResponse'] = $res;
                                                break;
                                        case AuthenticationResponse::FAIL;
                                                $this->logger->debug( __METHOD__ . ": Primary creation failed by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $res ] );
                                                $session->remove( 'AuthManager::accountCreationState' );
                                                return $res;
                                        case AuthenticationResponse::REDIRECT;
                                        case AuthenticationResponse::UI;
                                                $this->logger->debug( __METHOD__ . ": Primary creation $res->status by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                $this->fillRequests( $res->neededRequests, self::ACTION_CREATE, null );
                                                $state['continueRequests'] = $res->neededRequests;
                                                $session->setSecret( 'AuthManager::accountCreationState', $state );
                                                return $res;
                                        default:
                                                throw new \DomainException(
                                                        get_class( $provider ) . "::continuePrimaryAccountCreation() returned $res->status"
                                                );
                                }
                        }

                        // Step 2: Primary authentication succeeded, create the User object
                        // and add the user locally.

                        if ( $state['userid'] === 0 ) {
                                $this->logger->info( 'Creating user {user} during account creation', [
                                        'user' => $user->getName(),
                                        'creator' => $creator->getName(),
                                ] );
                                $status = $user->addToDatabase();
                                if ( !$status->isOK() ) {
                                        // @codeCoverageIgnoreStart
                                        $ret = AuthenticationResponse::newFail( $status->getMessage() );
                                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                                        $session->remove( 'AuthManager::accountCreationState' );
                                        return $ret;
                                        // @codeCoverageIgnoreEnd
                                }
                                $this->setDefaultUserOptions( $user, $creator->isAnon() );
                                \Hooks::run( 'LocalUserCreated', [ $user, false ] );
                                $user->saveSettings();
                                $state['userid'] = $user->getId();

                                // Update user count
                                \DeferredUpdates::addUpdate( new \SiteStatsUpdate( 0, 0, 0, 0, 1 ) );

                                // Watch user's userpage and talk page
                                $user->addWatch( $user->getUserPage(), User::IGNORE_USER_RIGHTS );

                                // Inform the provider
                                $logSubtype = $provider->finishAccountCreation( $user, $creator, $state['primaryResponse'] );

                                // Log the creation
                                if ( $this->config->get( 'NewUserLog' ) ) {
                                        $isAnon = $creator->isAnon();
                                        $logEntry = new \ManualLogEntry(
                                                'newusers',
                                                $logSubtype ?: ( $isAnon ? 'create' : 'create2' )
                                        );
                                        $logEntry->setPerformer( $isAnon ? $user : $creator );
                                        $logEntry->setTarget( $user->getUserPage() );
                                        /** @var CreationReasonAuthenticationRequest $req */
                                        $req = AuthenticationRequest::getRequestByClass(
                                                $state['reqs'], CreationReasonAuthenticationRequest::class
                                        );
                                        $logEntry->setComment( $req ? $req->reason : '' );
                                        $logEntry->setParameters( [
                                                '4::userid' => $user->getId(),
                                        ] );
                                        $logid = $logEntry->insert();
                                        $logEntry->publish( $logid );
                                }
                        }

                        // Step 3: Iterate over all the secondary authentication providers.

                        $beginReqs = $state['reqs'];

                        foreach ( $this->getSecondaryAuthenticationProviders() as $id => $provider ) {
                                if ( !isset( $state['secondary'][$id] ) ) {
                                        // This provider isn't started yet, so we pass it the set
                                        // of reqs from beginAuthentication instead of whatever
                                        // might have been used by a previous provider in line.
                                        $func = 'beginSecondaryAccountCreation';
                                        $res = $provider->beginSecondaryAccountCreation( $user, $creator, $beginReqs );
                                } elseif ( !$state['secondary'][$id] ) {
                                        $func = 'continueSecondaryAccountCreation';
                                        $res = $provider->continueSecondaryAccountCreation( $user, $creator, $reqs );
                                } else {
                                        continue;
                                }
                                switch ( $res->status ) {
                                        case AuthenticationResponse::PASS;
                                                $this->logger->debug( __METHOD__ . ": Secondary creation passed by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                // fall through
                                        case AuthenticationResponse::ABSTAIN;
                                                $state['secondary'][$id] = true;
                                                break;
                                        case AuthenticationResponse::REDIRECT;
                                        case AuthenticationResponse::UI;
                                                $this->logger->debug( __METHOD__ . ": Secondary creation $res->status by $id", [
                                                        'user' => $user->getName(),
                                                        'creator' => $creator->getName(),
                                                ] );
                                                $this->fillRequests( $res->neededRequests, self::ACTION_CREATE, null );
                                                $state['secondary'][$id] = false;
                                                $state['continueRequests'] = $res->neededRequests;
                                                $session->setSecret( 'AuthManager::accountCreationState', $state );
                                                return $res;
                                        case AuthenticationResponse::FAIL;
                                                throw new \DomainException(
                                                        get_class( $provider ) . "::{$func}() returned $res->status." .
                                                        ' Secondary providers are not allowed to fail account creation, that' .
                                                        ' should have been done via testForAccountCreation().'
                                                );
                                                        // @codeCoverageIgnoreStart
                                        default:
                                                throw new \DomainException(
                                                        get_class( $provider ) . "::{$func}() returned $res->status"
                                                );
                                                        // @codeCoverageIgnoreEnd
                                }
                        }

                        $id = $user->getId();
                        $name = $user->getName();
                        $req = new CreatedAccountAuthenticationRequest( $id, $name );
                        $ret = AuthenticationResponse::newPass( $name );
                        $ret->loginRequest = $req;
                        $this->createdAccountAuthenticationRequests[] = $req;

                        $this->logger->info( __METHOD__ . ': Account creation succeeded for {user}', [
                                'user' => $user->getName(),
                                'creator' => $creator->getName(),
                        ] );

                        $this->callMethodOnProviders( 7, 'postAccountCreation', [ $user, $creator, $ret ] );
                        $session->remove( 'AuthManager::accountCreationState' );
                        $this->removeAuthenticationSessionData( null );
                        return $ret;
                } catch ( \Exception $ex ) {
                        $session->remove( 'AuthManager::accountCreationState' );
                        throw $ex;
                }
        }

        /**
         * Auto-create an account, and log into that account
         *
         * PrimaryAuthenticationProviders can invoke this method by returning a PASS from
         * beginPrimaryAuthentication/continuePrimaryAuthentication with the username of a
         * non-existing user. SessionProviders can invoke it by returning a SessionInfo with
         * the username of a non-existing user from provideSessionInfo(). Calling this method
         * explicitly (e.g. from a maintenance script) is also fine.
         *
         * @param User $user User to auto-create
         * @param string $source What caused the auto-creation? This must be the ID
         *  of a PrimaryAuthenticationProvider or the constant self::AUTOCREATE_SOURCE_SESSION.
         * @param bool $login Whether to also log the user in
         * @return Status Good if user was created, Ok if user already existed, otherwise Fatal
         */
        public function autoCreateUser( User $user, $source, $login = true ) {
                if ( $source !== self::AUTOCREATE_SOURCE_SESSION &&
                        !$this->getAuthenticationProvider( $source ) instanceof PrimaryAuthenticationProvider
                ) {
                        throw new \InvalidArgumentException( "Unknown auto-creation source: $source" );
                }

                $username = $user->getName();

                // Try the local user from the replica DB
                $localId = User::idFromName( $username );
                $flags = User::READ_NORMAL;

                // Fetch the user ID from the master, so that we don't try to create the user
                // when they already exist, due to replication lag
                // @codeCoverageIgnoreStart
                if ( !$localId && wfGetLB()->getReaderIndex() != 0 ) {
                        $localId = User::idFromName( $username, User::READ_LATEST );
                        $flags = User::READ_LATEST;
                }
                // @codeCoverageIgnoreEnd

                if ( $localId ) {
                        $this->logger->debug( __METHOD__ . ': {username} already exists locally', [
                                'username' => $username,
                        ] );
                        $user->setId( $localId );
                        $user->loadFromId( $flags );
                        if ( $login ) {
                                $this->setSessionDataForUser( $user );
                        }
                        $status = Status::newGood();
                        $status->warning( 'userexists' );
                        return $status;
                }

                // Wiki is read-only?
                if ( wfReadOnly() ) {
                        $this->logger->debug( __METHOD__ . ': denied by wfReadOnly(): {reason}', [
                                'username' => $username,
                                'reason' => wfReadOnlyReason(),
                        ] );
                        $user->setId( 0 );
                        $user->loadFromId();
                        return Status::newFatal( 'readonlytext', wfReadOnlyReason() );
                }

                // Check the session, if we tried to create this user already there's
                // no point in retrying.
                $session = $this->request->getSession();
                if ( $session->get( 'AuthManager::AutoCreateBlacklist' ) ) {
                        $this->logger->debug( __METHOD__ . ': blacklisted in session {sessionid}', [
                                'username' => $username,
                                'sessionid' => $session->getId(),
                        ] );
                        $user->setId( 0 );
                        $user->loadFromId();
                        $reason = $session->get( 'AuthManager::AutoCreateBlacklist' );
                        if ( $reason instanceof StatusValue ) {
                                return Status::wrap( $reason );
                        } else {
                                return Status::newFatal( $reason );
                        }
                }

                // Is the username creatable?
                if ( !User::isCreatableName( $username ) ) {
                        $this->logger->debug( __METHOD__ . ': name "{username}" is not creatable', [
                                'username' => $username,
                        ] );
                        $session->set( 'AuthManager::AutoCreateBlacklist', 'noname' );
                        $user->setId( 0 );
                        $user->loadFromId();
                        return Status::newFatal( 'noname' );
                }

                // Is the IP user able to create accounts?
                $anon = new User;
                if ( !$anon->isAllowedAny( 'createaccount', 'autocreateaccount' ) ) {
                        $this->logger->debug( __METHOD__ . ': IP lacks the ability to create or autocreate accounts', [
                                'username' => $username,
                                'ip' => $anon->getName(),
                        ] );
                        $session->set( 'AuthManager::AutoCreateBlacklist', 'authmanager-autocreate-noperm' );
                        $session->persist();
                        $user->setId( 0 );
                        $user->loadFromId();
                        return Status::newFatal( 'authmanager-autocreate-noperm' );
                }

                // Avoid account creation races on double submissions
                $cache = \ObjectCache::getLocalClusterInstance();
                $lock = $cache->getScopedLock( $cache->makeGlobalKey( 'account', md5( $username ) ) );
                if ( !$lock ) {
                        $this->logger->debug( __METHOD__ . ': Could not acquire account creation lock', [
                                'user' => $username,
                        ] );
                        $user->setId( 0 );
                        $user->loadFromId();
                        return Status::newFatal( 'usernameinprogress' );
                }

                // Denied by providers?
                $options = [
                        'flags' => User::READ_LATEST,
                        'creating' => true,
                ];
                $providers = $this->getPreAuthenticationProviders() +
                        $this->getPrimaryAuthenticationProviders() +
                        $this->getSecondaryAuthenticationProviders();
                foreach ( $providers as $provider ) {
                        $status = $provider->testUserForCreation( $user, $source, $options );
                        if ( !$status->isGood() ) {
                                $ret = Status::wrap( $status );
                                $this->logger->debug( __METHOD__ . ': Provider denied creation of {username}: {reason}', [
                                        'username' => $username,
                                        'reason' => $ret->getWikiText( null, null, 'en' ),
                                ] );
                                $session->set( 'AuthManager::AutoCreateBlacklist', $status );
                                $user->setId( 0 );
                                $user->loadFromId();
                                return $ret;
                        }
                }

                $backoffKey = wfMemcKey( 'AuthManager', 'autocreate-failed', md5( $username ) );
                if ( $cache->get( $backoffKey ) ) {
                        $this->logger->debug( __METHOD__ . ': {username} denied by prior creation attempt failures', [
                                'username' => $username,
                        ] );
                        $user->setId( 0 );
                        $user->loadFromId();
                        return Status::newFatal( 'authmanager-autocreate-exception' );
                }

                // Checks passed, create the user...
                $from = isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : 'CLI';
                $this->logger->info( __METHOD__ . ': creating new user ({username}) - from: {from}', [
                        'username' => $username,
                        'from' => $from,
                ] );

                // Ignore warnings about master connections/writes...hard to avoid here
                $trxProfiler = \Profiler::instance()->getTransactionProfiler();
                $old = $trxProfiler->setSilenced( true );
                try {
                        $status = $user->addToDatabase();
                        if ( !$status->isOK() ) {
                                // Double-check for a race condition (T70012). We make use of the fact that when
                                // addToDatabase fails due to the user already existing, the user object gets loaded.
                                if ( $user->getId() ) {
                                        $this->logger->info( __METHOD__ . ': {username} already exists locally (race)', [
                                                'username' => $username,
                                        ] );
                                        if ( $login ) {
                                                $this->setSessionDataForUser( $user );
                                        }
                                        $status = Status::newGood();
                                        $status->warning( 'userexists' );
                                } else {
                                        $this->logger->error( __METHOD__ . ': {username} failed with message {msg}', [
                                                'username' => $username,
                                                'msg' => $status->getWikiText( null, null, 'en' )
                                        ] );
                                        $user->setId( 0 );
                                        $user->loadFromId();
                                }
                                return $status;
                        }
                } catch ( \Exception $ex ) {
                        $trxProfiler->setSilenced( $old );
                        $this->logger->error( __METHOD__ . ': {username} failed with exception {exception}', [
                                'username' => $username,
                                'exception' => $ex,
                        ] );
                        // Do not keep throwing errors for a while
                        $cache->set( $backoffKey, 1, 600 );
                        // Bubble up error; which should normally trigger DB rollbacks
                        throw $ex;
                }

                $this->setDefaultUserOptions( $user, false );

                // Inform the providers
                $this->callMethodOnProviders( 6, 'autoCreatedAccount', [ $user, $source ] );

                \Hooks::run( 'AuthPluginAutoCreate', [ $user ], '1.27' );
                \Hooks::run( 'LocalUserCreated', [ $user, true ] );
                $user->saveSettings();

                // Update user count
                \DeferredUpdates::addUpdate( new \SiteStatsUpdate( 0, 0, 0, 0, 1 ) );
                // Watch user's userpage and talk page
                \DeferredUpdates::addCallableUpdate( function () use ( $user ) {
                        $user->addWatch( $user->getUserPage(), User::IGNORE_USER_RIGHTS );
                } );

                // Log the creation
                if ( $this->config->get( 'NewUserLog' ) ) {
                        $logEntry = new \ManualLogEntry( 'newusers', 'autocreate' );
                        $logEntry->setPerformer( $user );
                        $logEntry->setTarget( $user->getUserPage() );
                        $logEntry->setComment( '' );
                        $logEntry->setParameters( [
                                '4::userid' => $user->getId(),
                        ] );
                        $logEntry->insert();
                }

                $trxProfiler->setSilenced( $old );

                if ( $login ) {
                        $this->setSessionDataForUser( $user );
                }

                return Status::newGood();
        }

        /**@}*/

        /**
         * @name Account linking
         * @{
         */

        /**
         * Determine whether accounts can be linked
         * @return bool
         */
        public function canLinkAccounts() {
                foreach ( $this->getPrimaryAuthenticationProviders() as $provider ) {
                        if ( $provider->accountCreationType() === PrimaryAuthenticationProvider::TYPE_LINK ) {
                                return true;
                        }
                }
                return false;
        }

        /**
         * Start an account linking flow
         *
         * @param User $user User being linked
         * @param AuthenticationRequest[] $reqs
         * @param string $returnToUrl Url that REDIRECT responses should eventually
         *  return to.
         * @return AuthenticationResponse
         */
        public function beginAccountLink( User $user, array $reqs, $returnToUrl ) {
                $session = $this->request->getSession();
                $session->remove( 'AuthManager::accountLinkState' );

                if ( !$this->canLinkAccounts() ) {
                        // Caller should have called canLinkAccounts()
                        throw new \LogicException( 'Account linking is not possible' );
                }

                if ( $user->getId() === 0 ) {
                        if ( !User::isUsableName( $user->getName() ) ) {
                                $msg = wfMessage( 'noname' );
                        } else {
                                $msg = wfMessage( 'authmanager-userdoesnotexist', $user->getName() );
                        }
                        return AuthenticationResponse::newFail( $msg );
                }
                foreach ( $reqs as $req ) {
                        $req->username = $user->getName();
                        $req->returnToUrl = $returnToUrl;
                }

                $this->removeAuthenticationSessionData( null );

                $providers = $this->getPreAuthenticationProviders();
                foreach ( $providers as $id => $provider ) {
                        $status = $provider->testForAccountLink( $user );
                        if ( !$status->isGood() ) {
                                $this->logger->debug( __METHOD__ . ": Account linking pre-check failed by $id", [
                                        'user' => $user->getName(),
                                ] );
                                $ret = AuthenticationResponse::newFail(
                                        Status::wrap( $status )->getMessage()
                                );
                                $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $ret ] );
                                return $ret;
                        }
                }

                $state = [
                        'username' => $user->getName(),
                        'userid' => $user->getId(),
                        'returnToUrl' => $returnToUrl,
                        'primary' => null,
                        'continueRequests' => [],
                ];

                $providers = $this->getPrimaryAuthenticationProviders();
                foreach ( $providers as $id => $provider ) {
                        if ( $provider->accountCreationType() !== PrimaryAuthenticationProvider::TYPE_LINK ) {
                                continue;
                        }

                        $res = $provider->beginPrimaryAccountLink( $user, $reqs );
                        switch ( $res->status ) {
                                case AuthenticationResponse::PASS;
                                        $this->logger->info( "Account linked to {user} by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $res ] );
                                        return $res;

                                case AuthenticationResponse::FAIL;
                                        $this->logger->debug( __METHOD__ . ": Account linking failed by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $res ] );
                                        return $res;

                                case AuthenticationResponse::ABSTAIN;
                                        // Continue loop
                                        break;

                                case AuthenticationResponse::REDIRECT;
                                case AuthenticationResponse::UI;
                                        $this->logger->debug( __METHOD__ . ": Account linking $res->status by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->fillRequests( $res->neededRequests, self::ACTION_LINK, $user->getName() );
                                        $state['primary'] = $id;
                                        $state['continueRequests'] = $res->neededRequests;
                                        $session->setSecret( 'AuthManager::accountLinkState', $state );
                                        $session->persist();
                                        return $res;

                                        // @codeCoverageIgnoreStart
                                default:
                                        throw new \DomainException(
                                                get_class( $provider ) . "::beginPrimaryAccountLink() returned $res->status"
                                        );
                                        // @codeCoverageIgnoreEnd
                        }
                }

                $this->logger->debug( __METHOD__ . ': Account linking failed because no provider accepted', [
                        'user' => $user->getName(),
                ] );
                $ret = AuthenticationResponse::newFail(
                        wfMessage( 'authmanager-link-no-primary' )
                );
                $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $ret ] );
                return $ret;
        }

        /**
         * Continue an account linking flow
         * @param AuthenticationRequest[] $reqs
         * @return AuthenticationResponse
         */
        public function continueAccountLink( array $reqs ) {
                $session = $this->request->getSession();
                try {
                        if ( !$this->canLinkAccounts() ) {
                                // Caller should have called canLinkAccounts()
                                $session->remove( 'AuthManager::accountLinkState' );
                                throw new \LogicException( 'Account linking is not possible' );
                        }

                        $state = $session->getSecret( 'AuthManager::accountLinkState' );
                        if ( !is_array( $state ) ) {
                                return AuthenticationResponse::newFail(
                                        wfMessage( 'authmanager-link-not-in-progress' )
                                );
                        }
                        $state['continueRequests'] = [];

                        // Step 0: Prepare and validate the input

                        $user = User::newFromName( $state['username'], 'usable' );
                        if ( !is_object( $user ) ) {
                                $session->remove( 'AuthManager::accountLinkState' );
                                return AuthenticationResponse::newFail( wfMessage( 'noname' ) );
                        }
                        if ( $user->getId() != $state['userid'] ) {
                                throw new \UnexpectedValueException(
                                        "User \"{$state['username']}\" is valid, but " .
                                                "ID {$user->getId()} != {$state['userid']}!"
                                );
                        }

                        foreach ( $reqs as $req ) {
                                $req->username = $state['username'];
                                $req->returnToUrl = $state['returnToUrl'];
                        }

                        // Step 1: Call the primary again until it succeeds

                        $provider = $this->getAuthenticationProvider( $state['primary'] );
                        if ( !$provider instanceof PrimaryAuthenticationProvider ) {
                                // Configuration changed? Force them to start over.
                                // @codeCoverageIgnoreStart
                                $ret = AuthenticationResponse::newFail(
                                        wfMessage( 'authmanager-link-not-in-progress' )
                                );
                                $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $ret ] );
                                $session->remove( 'AuthManager::accountLinkState' );
                                return $ret;
                                // @codeCoverageIgnoreEnd
                        }
                        $id = $provider->getUniqueId();
                        $res = $provider->continuePrimaryAccountLink( $user, $reqs );
                        switch ( $res->status ) {
                                case AuthenticationResponse::PASS;
                                        $this->logger->info( "Account linked to {user} by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $res ] );
                                        $session->remove( 'AuthManager::accountLinkState' );
                                        return $res;
                                case AuthenticationResponse::FAIL;
                                        $this->logger->debug( __METHOD__ . ": Account linking failed by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->callMethodOnProviders( 3, 'postAccountLink', [ $user, $res ] );
                                        $session->remove( 'AuthManager::accountLinkState' );
                                        return $res;
                                case AuthenticationResponse::REDIRECT;
                                case AuthenticationResponse::UI;
                                        $this->logger->debug( __METHOD__ . ": Account linking $res->status by $id", [
                                                'user' => $user->getName(),
                                        ] );
                                        $this->fillRequests( $res->neededRequests, self::ACTION_LINK, $user->getName() );
                                        $state['continueRequests'] = $res->neededRequests;
                                        $session->setSecret( 'AuthManager::accountLinkState', $state );
                                        return $res;
                                default:
                                        throw new \DomainException(
                                                get_class( $provider ) . "::continuePrimaryAccountLink() returned $res->status"
                                        );
                        }
                } catch ( \Exception $ex ) {
                        $session->remove( 'AuthManager::accountLinkState' );
                        throw $ex;
                }
        }

        /**@}*/

        /**
         * @name Information methods
         * @{
         */

        /**
         * Return the applicable list of AuthenticationRequests
         *
         * Possible values for $action:
         *  - ACTION_LOGIN: Valid for passing to beginAuthentication
         *  - ACTION_LOGIN_CONTINUE: Valid for passing to continueAuthentication in the current state
         *  - ACTION_CREATE: Valid for passing to beginAccountCreation
         *  - ACTION_CREATE_CONTINUE: Valid for passing to continueAccountCreation in the current state
         *  - ACTION_LINK: Valid for passing to beginAccountLink
         *  - ACTION_LINK_CONTINUE: Valid for passing to continueAccountLink in the current state
         *  - ACTION_CHANGE: Valid for passing to changeAuthenticationData to change credentials
         *  - ACTION_REMOVE: Valid for passing to changeAuthenticationData to remove credentials.
         *  - ACTION_UNLINK: Same as ACTION_REMOVE, but limited to linked accounts.
         *
         * @param string $action One of the AuthManager::ACTION_* constants
         * @param User|null $user User being acted on, instead of the current user.
         * @return AuthenticationRequest[]
         */
        public function getAuthenticationRequests( $action, User $user = null ) {
                $options = [];
                $providerAction = $action;

                // Figure out which providers to query
                switch ( $action ) {
                        case self::ACTION_LOGIN:
                        case self::ACTION_CREATE:
                                $providers = $this->getPreAuthenticationProviders() +
                                        $this->getPrimaryAuthenticationProviders() +
                                        $this->getSecondaryAuthenticationProviders();
                                break;

                        case self::ACTION_LOGIN_CONTINUE:
                                $state = $this->request->getSession()->getSecret( 'AuthManager::authnState' );
                                return is_array( $state ) ? $state['continueRequests'] : [];

                        case self::ACTION_CREATE_CONTINUE:
                                $state = $this->request->getSession()->getSecret( 'AuthManager::accountCreationState' );
                                return is_array( $state ) ? $state['continueRequests'] : [];

                        case self::ACTION_LINK:
                                $providers = array_filter( $this->getPrimaryAuthenticationProviders(), function ( $p ) {
                                        return $p->accountCreationType() === PrimaryAuthenticationProvider::TYPE_LINK;
                                } );
                                break;

                        case self::ACTION_UNLINK:
                                $providers = array_filter( $this->getPrimaryAuthenticationProviders(), function ( $p ) {
                                        return $p->accountCreationType() === PrimaryAuthenticationProvider::TYPE_LINK;
                                } );

                                // To providers, unlink and remove are identical.
                                $providerAction = self::ACTION_REMOVE;
                                break;

                        case self::ACTION_LINK_CONTINUE:
                                $state = $this->request->getSession()->getSecret( 'AuthManager::accountLinkState' );
                                return is_array( $state ) ? $state['continueRequests'] : [];

                        case self::ACTION_CHANGE:
                        case self::ACTION_REMOVE:
                                $providers = $this->getPrimaryAuthenticationProviders() +
                                        $this->getSecondaryAuthenticationProviders();
                                break;

                        // @codeCoverageIgnoreStart
                        default:
                                throw new \DomainException( __METHOD__ . ": Invalid action \"$action\"" );
                }
                // @codeCoverageIgnoreEnd

                return $this->getAuthenticationRequestsInternal( $providerAction, $options, $providers, $user );
        }

        /**
         * Internal request lookup for self::getAuthenticationRequests
         *
         * @param string $providerAction Action to pass to providers
         * @param array $options Options to pass to providers
         * @param AuthenticationProvider[] $providers
         * @param User|null $user
         * @return AuthenticationRequest[]
         */
        private function getAuthenticationRequestsInternal(
                $providerAction, array $options, array $providers, User $user = null
        ) {
                $user = $user ?: \RequestContext::getMain()->getUser();
                $options['username'] = $user->isAnon() ? null : $user->getName();

                // Query them and merge results
                $reqs = [];
                foreach ( $providers as $provider ) {
                        $isPrimary = $provider instanceof PrimaryAuthenticationProvider;
                        foreach ( $provider->getAuthenticationRequests( $providerAction, $options ) as $req ) {
                                $id = $req->getUniqueId();

                                // If a required request if from a Primary, mark it as "primary-required" instead
                                if ( $isPrimary ) {
                                        if ( $req->required ) {
                                                $req->required = AuthenticationRequest::PRIMARY_REQUIRED;
                                        }
                                }

                                if (
                                        !isset( $reqs[$id] )
                                        || $req->required === AuthenticationRequest::REQUIRED
                                        || $reqs[$id] === AuthenticationRequest::OPTIONAL
                                ) {
                                        $reqs[$id] = $req;
                                }
                        }
                }

                // AuthManager has its own req for some actions
                switch ( $providerAction ) {
                        case self::ACTION_LOGIN:
                                $reqs[] = new RememberMeAuthenticationRequest;
                                break;

                        case self::ACTION_CREATE:
                                $reqs[] = new UsernameAuthenticationRequest;
                                $reqs[] = new UserDataAuthenticationRequest;
                                if ( $options['username'] !== null ) {
                                        $reqs[] = new CreationReasonAuthenticationRequest;
                                        $options['username'] = null; // Don't fill in the username below
                                }
                                break;
                }

                // Fill in reqs data
                $this->fillRequests( $reqs, $providerAction, $options['username'], true );

                // For self::ACTION_CHANGE, filter out any that something else *doesn't* allow changing
                if ( $providerAction === self::ACTION_CHANGE || $providerAction === self::ACTION_REMOVE ) {
                        $reqs = array_filter( $reqs, function ( $req ) {
                                return $this->allowsAuthenticationDataChange( $req, false )->isGood();
                        } );
                }

                return array_values( $reqs );
        }

        /**
         * Set values in an array of requests
         * @param AuthenticationRequest[] &$reqs
         * @param string $action
         * @param string|null $username
         * @param boolean $forceAction
         */
        private function fillRequests( array &$reqs, $action, $username, $forceAction = false ) {
                foreach ( $reqs as $req ) {
                        if ( !$req->action || $forceAction ) {
                                $req->action = $action;
                        }
                        if ( $req->username === null ) {
                                $req->username = $username;
                        }
                }
        }

        /**
         * Determine whether a username exists
         * @param string $username
         * @param int $flags Bitfield of User:READ_* constants
         * @return bool
         */
        public function userExists( $username, $flags = User::READ_NORMAL ) {
                foreach ( $this->getPrimaryAuthenticationProviders() as $provider ) {
                        if ( $provider->testUserExists( $username, $flags ) ) {
                                return true;
                        }
                }

                return false;
        }

        /**
         * Determine whether a user property should be allowed to be changed.
         *
         * Supported properties are:
         *  - emailaddress
         *  - realname
         *  - nickname
         *
         * @param string $property
         * @return bool
         */
        public function allowsPropertyChange( $property ) {
                $providers = $this->getPrimaryAuthenticationProviders() +
                        $this->getSecondaryAuthenticationProviders();
                foreach ( $providers as $provider ) {
                        if ( !$provider->providerAllowsPropertyChange( $property ) ) {
                                return false;
                        }
                }
                return true;
        }

        /**
         * Get a provider by ID
         * @note This is public so extensions can check whether their own provider
         *  is installed and so they can read its configuration if necessary.
         *  Other uses are not recommended.
         * @param string $id
         * @return AuthenticationProvider|null
         */
        public function getAuthenticationProvider( $id ) {
                // Fast version
                if ( isset( $this->allAuthenticationProviders[$id] ) ) {
                        return $this->allAuthenticationProviders[$id];
                }

                // Slow version: instantiate each kind and check
                $providers = $this->getPrimaryAuthenticationProviders();
                if ( isset( $providers[$id] ) ) {
                        return $providers[$id];
                }
                $providers = $this->getSecondaryAuthenticationProviders();
                if ( isset( $providers[$id] ) ) {
                        return $providers[$id];
                }
                $providers = $this->getPreAuthenticationProviders();
                if ( isset( $providers[$id] ) ) {
                        return $providers[$id];
                }

                return null;
        }

        /**@}*/

        /**
         * @name Internal methods
         * @{
         */

        /**
         * Store authentication in the current session
         * @protected For use by AuthenticationProviders
         * @param string $key
         * @param mixed $data Must be serializable
         */
        public function setAuthenticationSessionData( $key, $data ) {
                $session = $this->request->getSession();
                $arr = $session->getSecret( 'authData' );
                if ( !is_array( $arr ) ) {
                        $arr = [];
                }
                $arr[$key] = $data;
                $session->setSecret( 'authData', $arr );
        }

        /**
         * Fetch authentication data from the current session
         * @protected For use by AuthenticationProviders
         * @param string $key
         * @param mixed $default
         * @return mixed
         */
        public function getAuthenticationSessionData( $key, $default = null ) {
                $arr = $this->request->getSession()->getSecret( 'authData' );
                if ( is_array( $arr ) && array_key_exists( $key, $arr ) ) {
                        return $arr[$key];
                } else {
                        return $default;
                }
        }

        /**
         * Remove authentication data
         * @protected For use by AuthenticationProviders
         * @param string|null $key If null, all data is removed
         */
        public function removeAuthenticationSessionData( $key ) {
                $session = $this->request->getSession();
                if ( $key === null ) {
                        $session->remove( 'authData' );
                } else {
                        $arr = $session->getSecret( 'authData' );
                        if ( is_array( $arr ) && array_key_exists( $key, $arr ) ) {
                                unset( $arr[$key] );
                                $session->setSecret( 'authData', $arr );
                        }
                }
        }

        /**
         * Create an array of AuthenticationProviders from an array of ObjectFactory specs
         * @param string $class
         * @param array[] $specs
         * @return AuthenticationProvider[]
         */
        protected function providerArrayFromSpecs( $class, array $specs ) {
                $i = 0;
                foreach ( $specs as &$spec ) {
                        $spec = [ 'sort2' => $i++ ] + $spec + [ 'sort' => 0 ];
                }
                unset( $spec );
                usort( $specs, function ( $a, $b ) {
                        return ( (int)$a['sort'] ) - ( (int)$b['sort'] )
                                ?: $a['sort2'] - $b['sort2'];
                } );

                $ret = [];
                foreach ( $specs as $spec ) {
                        $provider = \ObjectFactory::getObjectFromSpec( $spec );
                        if ( !$provider instanceof $class ) {
                                throw new \RuntimeException(
                                        "Expected instance of $class, got " . get_class( $provider )
                                );
                        }
                        $provider->setLogger( $this->logger );
                        $provider->setManager( $this );
                        $provider->setConfig( $this->config );
                        $id = $provider->getUniqueId();
                        if ( isset( $this->allAuthenticationProviders[$id] ) ) {
                                throw new \RuntimeException(
                                        "Duplicate specifications for id $id (classes " .
                                        get_class( $provider ) . ' and ' .
                                        get_class( $this->allAuthenticationProviders[$id] ) . ')'
                                );
                        }
                        $this->allAuthenticationProviders[$id] = $provider;
                        $ret[$id] = $provider;
                }
                return $ret;
        }

        /**
         * Get the configuration
         * @return array
         */
        private function getConfiguration() {
                return $this->config->get( 'AuthManagerConfig' ) ?: $this->config->get( 'AuthManagerAutoConfig' );
        }

        /**
         * Get the list of PreAuthenticationProviders
         * @return PreAuthenticationProvider[]
         */
        protected function getPreAuthenticationProviders() {
                if ( $this->preAuthenticationProviders === null ) {
                        $conf = $this->getConfiguration();
                        $this->preAuthenticationProviders = $this->providerArrayFromSpecs(
                                PreAuthenticationProvider::class, $conf['preauth']
                        );
                }
                return $this->preAuthenticationProviders;
        }

        /**
         * Get the list of PrimaryAuthenticationProviders
         * @return PrimaryAuthenticationProvider[]
         */
        protected function getPrimaryAuthenticationProviders() {
                if ( $this->primaryAuthenticationProviders === null ) {
                        $conf = $this->getConfiguration();
                        $this->primaryAuthenticationProviders = $this->providerArrayFromSpecs(
                                PrimaryAuthenticationProvider::class, $conf['primaryauth']
                        );
                }
                return $this->primaryAuthenticationProviders;
        }

        /**
         * Get the list of SecondaryAuthenticationProviders
         * @return SecondaryAuthenticationProvider[]
         */
        protected function getSecondaryAuthenticationProviders() {
                if ( $this->secondaryAuthenticationProviders === null ) {
                        $conf = $this->getConfiguration();
                        $this->secondaryAuthenticationProviders = $this->providerArrayFromSpecs(
                                SecondaryAuthenticationProvider::class, $conf['secondaryauth']
                        );
                }
                return $this->secondaryAuthenticationProviders;
        }

        /**
         * Log the user in
         * @param User $user
         * @param bool|null $remember
         */
        private function setSessionDataForUser( $user, $remember = null ) {
                $session = $this->request->getSession();
                $delay = $session->delaySave();

                $session->resetId();
                $session->resetAllTokens();
                if ( $session->canSetUser() ) {
                        $session->setUser( $user );
                }
                if ( $remember !== null ) {
                        $session->setRememberUser( $remember );
                }
                $session->set( 'AuthManager:lastAuthId', $user->getId() );
                $session->set( 'AuthManager:lastAuthTimestamp', time() );
                $session->persist();

                \Wikimedia\ScopedCallback::consume( $delay );

                \Hooks::run( 'UserLoggedIn', [ $user ] );
        }

        /**
         * @param User $user
         * @param bool $useContextLang Use 'uselang' to set the user's language
         */
        private function setDefaultUserOptions( User $user, $useContextLang ) {
                global $wgContLang;

                $user->setToken();

                $lang = $useContextLang ? \RequestContext::getMain()->getLanguage() : $wgContLang;
                $user->setOption( 'language', $lang->getPreferredVariant() );

                if ( $wgContLang->hasVariants() ) {
                        $user->setOption( 'variant', $wgContLang->getPreferredVariant() );
                }
        }

        /**
         * @param int $which Bitmask: 1 = pre, 2 = primary, 4 = secondary
         * @param string $method
         * @param array $args
         */
        private function callMethodOnProviders( $which, $method, array $args ) {
                $providers = [];
                if ( $which & 1 ) {
                        $providers += $this->getPreAuthenticationProviders();
                }
                if ( $which & 2 ) {
                        $providers += $this->getPrimaryAuthenticationProviders();
                }
                if ( $which & 4 ) {
                        $providers += $this->getSecondaryAuthenticationProviders();
                }
                foreach ( $providers as $provider ) {
                        call_user_func_array( [ $provider, $method ], $args );
                }
        }

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

                self::$instance = null;
        }

        /**@}*/

}

/**
 * For really cool vim folding this needs to be at the end:
 * vim: foldmarker=@{,@} foldmethod=marker
 */