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diff --git a/www/wiki/includes/auth/Throttler.php b/www/wiki/includes/auth/Throttler.php
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+++ b/www/wiki/includes/auth/Throttler.php
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+<?php
+/**
+ * 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 BagOStuff;
+use MediaWiki\Logger\LoggerFactory;
+use MediaWiki\MediaWikiServices;
+use Psr\Log\LoggerAwareInterface;
+use Psr\Log\LoggerInterface;
+use Psr\Log\LogLevel;
+
+/**
+ * A helper class for throttling authentication attempts.
+ * @package MediaWiki\Auth
+ * @ingroup Auth
+ * @since 1.27
+ */
+class Throttler implements LoggerAwareInterface {
+	/** @var string */
+	protected $type;
+	/**
+	 * See documentation of $wgPasswordAttemptThrottle for format. Old (pre-1.27) format is not
+	 * allowed here.
+	 * @var array
+	 * @see https://www.mediawiki.org/wiki/Manual:$wgPasswordAttemptThrottle
+	 */
+	protected $conditions;
+	/** @var BagOStuff */
+	protected $cache;
+	/** @var LoggerInterface */
+	protected $logger;
+	/** @var int|float */
+	protected $warningLimit;
+
+	/**
+	 * @param array $conditions An array of arrays describing throttling conditions.
+	 *     Defaults to $wgPasswordAttemptThrottle. See documentation of that variable for format.
+	 * @param array $params Parameters (all optional):
+	 *   - type: throttle type, used as a namespace for counters,
+	 *   - cache: a BagOStuff object where throttle counters are stored.
+	 *   - warningLimit: the log level will be raised to warning when rejecting an attempt after
+	 *     no less than this many failures.
+	 */
+	public function __construct( array $conditions = null, array $params = [] ) {
+		$invalidParams = array_diff_key( $params,
+			array_fill_keys( [ 'type', 'cache', 'warningLimit' ], true ) );
+		if ( $invalidParams ) {
+			throw new \InvalidArgumentException( 'unrecognized parameters: '
+				. implode( ', ', array_keys( $invalidParams ) ) );
+		}
+
+		if ( $conditions === null ) {
+			$config = MediaWikiServices::getInstance()->getMainConfig();
+			$conditions = $config->get( 'PasswordAttemptThrottle' );
+			$params += [
+				'type' => 'password',
+				'cache' => \ObjectCache::getLocalClusterInstance(),
+				'warningLimit' => 50,
+			];
+		} else {
+			$params += [
+				'type' => 'custom',
+				'cache' => \ObjectCache::getLocalClusterInstance(),
+				'warningLimit' => INF,
+			];
+		}
+
+		$this->type = $params['type'];
+		$this->conditions = static::normalizeThrottleConditions( $conditions );
+		$this->cache = $params['cache'];
+		$this->warningLimit = $params['warningLimit'];
+
+		$this->setLogger( LoggerFactory::getInstance( 'throttler' ) );
+	}
+
+	public function setLogger( LoggerInterface $logger ) {
+		$this->logger = $logger;
+	}
+
+	/**
+	 * Increase the throttle counter and return whether the attempt should be throttled.
+	 *
+	 * Should be called before an authentication attempt.
+	 *
+	 * @param string|null $username
+	 * @param string|null $ip
+	 * @param string|null $caller The authentication method from which we were called.
+	 * @return array|false False if the attempt should not be throttled, an associative array
+	 *   with three keys otherwise:
+	 *   - throttleIndex: which throttle condition was met (a key of the conditions array)
+	 *   - count: throttle count (ie. number of failed attempts)
+	 *   - wait: time in seconds until authentication can be attempted
+	 */
+	public function increase( $username = null, $ip = null, $caller = null ) {
+		if ( $username === null && $ip === null ) {
+			throw new \InvalidArgumentException( 'Either username or IP must be set for throttling' );
+		}
+
+		$userKey = $username ? md5( $username ) : null;
+		foreach ( $this->conditions as $index => $throttleCondition ) {
+			$ipKey = isset( $throttleCondition['allIPs'] ) ? null : $ip;
+			$count = $throttleCondition['count'];
+			$expiry = $throttleCondition['seconds'];
+
+			// a limit of 0 is used as a disable flag in some throttling configuration settings
+			// throttling the whole world is probably a bad idea
+			if ( !$count || $userKey === null && $ipKey === null ) {
+				continue;
+			}
+
+			$throttleKey = $this->cache->makeGlobalKey( 'throttler', $this->type, $index, $ipKey, $userKey );
+			$throttleCount = $this->cache->get( $throttleKey );
+
+			if ( !$throttleCount ) { // counter not started yet
+				$this->cache->add( $throttleKey, 1, $expiry );
+			} elseif ( $throttleCount < $count ) { // throttle limited not yet reached
+				$this->cache->incr( $throttleKey );
+			} else { // throttled
+				$this->logRejection( [
+					'throttle' => $this->type,
+					'index' => $index,
+					'ip' => $ipKey,
+					'username' => $username,
+					'count' => $count,
+					'expiry' => $expiry,
+					// @codeCoverageIgnoreStart
+					'method' => $caller ?: __METHOD__,
+					// @codeCoverageIgnoreEnd
+				] );
+
+				return [
+					'throttleIndex' => $index,
+					'count' => $count,
+					'wait' => $expiry,
+				];
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * Clear the throttle counter.
+	 *
+	 * Should be called after a successful authentication attempt.
+	 *
+	 * @param string|null $username
+	 * @param string|null $ip
+	 * @throws \MWException
+	 */
+	public function clear( $username = null, $ip = null ) {
+		$userKey = $username ? md5( $username ) : null;
+		foreach ( $this->conditions as $index => $specificThrottle ) {
+			$ipKey = isset( $specificThrottle['allIPs'] ) ? null : $ip;
+			$throttleKey = $this->cache->makeGlobalKey( 'throttler', $this->type, $index, $ipKey, $userKey );
+			$this->cache->delete( $throttleKey );
+		}
+	}
+
+	/**
+	 * Handles B/C for $wgPasswordAttemptThrottle.
+	 * @param array $throttleConditions
+	 * @return array
+	 * @see $wgPasswordAttemptThrottle for structure
+	 */
+	protected static function normalizeThrottleConditions( $throttleConditions ) {
+		if ( !is_array( $throttleConditions ) ) {
+			return [];
+		}
+		if ( isset( $throttleConditions['count'] ) ) { // old style
+			$throttleConditions = [ $throttleConditions ];
+		}
+		return $throttleConditions;
+	}
+
+	protected function logRejection( array $context ) {
+		$logMsg = 'Throttle {throttle} hit, throttled for {expiry} seconds due to {count} attempts '
+			. 'from username {username} and IP {ip}';
+
+		// If we are hitting a throttle for >= warningLimit attempts, it is much more likely to be
+		// an attack than someone simply forgetting their password, so log it at a higher level.
+		$level = $context['count'] >= $this->warningLimit ? LogLevel::WARNING : LogLevel::INFO;
+
+		// It should be noted that once the throttle is hit, every attempt to login will
+		// generate the log message until the throttle expires, not just the attempt that
+		// puts the throttle over the top.
+		$this->logger->log( $level, $logMsg, $context );
+	}
+
+}