includes/auth/Throttler.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @ingroup Auth
  20  */
  21
  22 namespace MediaWiki\Auth;
  23
  24 use BagOStuff;
  25 use MediaWiki\Logger\LoggerFactory;
  26 use MediaWiki\MediaWikiServices;
  27 use Psr\Log\LoggerAwareInterface;
  28 use Psr\Log\LoggerInterface;
  29 use Psr\Log\LogLevel;
  30
  31 /**
  32  * A helper class for throttling authentication attempts.
  33  * @package MediaWiki\Auth
  34  * @ingroup Auth
  35  * @since 1.27
  36  */
  37 class Throttler implements LoggerAwareInterface {
  38         /** @var string */
  39         protected $type;
  40         /**
  41          * See documentation of $wgPasswordAttemptThrottle for format. Old (pre-1.27) format is not
  42          * allowed here.
  43          * @var array[]
  44          * @see https://www.mediawiki.org/wiki/Manual:$wgPasswordAttemptThrottle
  45          */
  46         protected $conditions;
  47         /** @var BagOStuff */
  48         protected $cache;
  49         /** @var LoggerInterface */
  50         protected $logger;
  51         /** @var int|float */
  52         protected $warningLimit;
  53
  54         /**
  55          * @param array|null $conditions An array of arrays describing throttling conditions.
  56          *     Defaults to $wgPasswordAttemptThrottle. See documentation of that variable for format.
  57          * @param array $params Parameters (all optional):
  58          *   - type: throttle type, used as a namespace for counters,
  59          *   - cache: a BagOStuff object where throttle counters are stored.
  60          *   - warningLimit: the log level will be raised to warning when rejecting an attempt after
  61          *     no less than this many failures.
  62          */
  63         public function __construct( array $conditions = null, array $params = [] ) {
  64                 $invalidParams = array_diff_key( $params,
  65                         array_fill_keys( [ 'type', 'cache', 'warningLimit' ], true ) );
  66                 if ( $invalidParams ) {
  67                         throw new \InvalidArgumentException( 'unrecognized parameters: '
  68                                 . implode( ', ', array_keys( $invalidParams ) ) );
  69                 }
  70
  71                 if ( $conditions === null ) {
  72                         $config = MediaWikiServices::getInstance()->getMainConfig();
  73                         $conditions = $config->get( 'PasswordAttemptThrottle' );
  74                         $params += [
  75                                 'type' => 'password',
  76                                 'cache' => \ObjectCache::getLocalClusterInstance(),
  77                                 'warningLimit' => 50,
  78                         ];
  79                 } else {
  80                         $params += [
  81                                 'type' => 'custom',
  82                                 'cache' => \ObjectCache::getLocalClusterInstance(),
  83                                 'warningLimit' => INF,
  84                         ];
  85                 }
  86
  87                 $this->type = $params['type'];
  88                 $this->conditions = static::normalizeThrottleConditions( $conditions );
  89                 $this->cache = $params['cache'];
  90                 $this->warningLimit = $params['warningLimit'];
  91
  92                 $this->setLogger( LoggerFactory::getInstance( 'throttler' ) );
  93         }
  94
  95         public function setLogger( LoggerInterface $logger ) {
  96                 $this->logger = $logger;
  97         }
  98
  99         /**
 100          * Increase the throttle counter and return whether the attempt should be throttled.
 101          *
 102          * Should be called before an authentication attempt.
 103          *
 104          * @param string|null $username
 105          * @param string|null $ip
 106          * @param string|null $caller The authentication method from which we were called.
 107          * @return array|false False if the attempt should not be throttled, an associative array
 108          *   with three keys otherwise:
 109          *   - throttleIndex: which throttle condition was met (a key of the conditions array)
 110          *   - count: throttle count (ie. number of failed attempts)
 111          *   - wait: time in seconds until authentication can be attempted
 112          */
 113         public function increase( $username = null, $ip = null, $caller = null ) {
 114                 if ( $username === null && $ip === null ) {
 115                         throw new \InvalidArgumentException( 'Either username or IP must be set for throttling' );
 116                 }
 117
 118                 $userKey = $username ? md5( $username ) : null;
 119                 foreach ( $this->conditions as $index => $throttleCondition ) {
 120                         $ipKey = isset( $throttleCondition['allIPs'] ) ? null : $ip;
 121                         $count = $throttleCondition['count'];
 122                         $expiry = $throttleCondition['seconds'];
 123
 124                         // a limit of 0 is used as a disable flag in some throttling configuration settings
 125                         // throttling the whole world is probably a bad idea
 126                         if ( !$count || $userKey === null && $ipKey === null ) {
 127                                 continue;
 128                         }
 129
 130                         $throttleKey = $this->cache->makeGlobalKey(
 131                                 'throttler',
 132                                 $this->type,
 133                                 $index,
 134                                 $ipKey,
 135                                 $userKey
 136                         );
 137                         $throttleCount = $this->cache->get( $throttleKey );
 138                         if ( $throttleCount && $throttleCount >= $count ) {
 139                                 // Throttle limited reached
 140                                 $this->logRejection( [
 141                                         'throttle' => $this->type,
 142                                         'index' => $index,
 143                                         'ipKey' => $ipKey,
 144                                         'username' => $username,
 145                                         'count' => $count,
 146                                         'expiry' => $expiry,
 147                                         // @codeCoverageIgnoreStart
 148                                         'method' => $caller ?: __METHOD__,
 149                                         // @codeCoverageIgnoreEnd
 150                                 ] );
 151
 152                                 return [ 'throttleIndex' => $index, 'count' => $count, 'wait' => $expiry ];
 153                         } else {
 154                                 $this->cache->incrWithInit( $throttleKey, $expiry, 1 );
 155                         }
 156                 }
 157
 158                 return false;
 159         }
 160
 161         /**
 162          * Clear the throttle counter.
 163          *
 164          * Should be called after a successful authentication attempt.
 165          *
 166          * @param string|null $username
 167          * @param string|null $ip
 168          * @throws \MWException
 169          */
 170         public function clear( $username = null, $ip = null ) {
 171                 $userKey = $username ? md5( $username ) : null;
 172                 foreach ( $this->conditions as $index => $specificThrottle ) {
 173                         $ipKey = isset( $specificThrottle['allIPs'] ) ? null : $ip;
 174                         $throttleKey = $this->cache->makeGlobalKey( 'throttler', $this->type, $index, $ipKey, $userKey );
 175                         $this->cache->delete( $throttleKey );
 176                 }
 177         }
 178
 179         /**
 180          * Handles B/C for $wgPasswordAttemptThrottle.
 181          * @param array $throttleConditions
 182          * @return array[]
 183          * @see $wgPasswordAttemptThrottle for structure
 184          */
 185         protected static function normalizeThrottleConditions( $throttleConditions ) {
 186                 if ( !is_array( $throttleConditions ) ) {
 187                         return [];
 188                 }
 189                 if ( isset( $throttleConditions['count'] ) ) { // old style
 190                         $throttleConditions = [ $throttleConditions ];
 191                 }
 192                 return $throttleConditions;
 193         }
 194
 195         protected function logRejection( array $context ) {
 196                 $logMsg = 'Throttle {throttle} hit, throttled for {expiry} seconds due to {count} attempts '
 197                         . 'from username {username} and IP {ipKey}';
 198
 199                 // If we are hitting a throttle for >= warningLimit attempts, it is much more likely to be
 200                 // an attack than someone simply forgetting their password, so log it at a higher level.
 201                 $level = $context['count'] >= $this->warningLimit ? LogLevel::WARNING : LogLevel::INFO;
 202
 203                 // It should be noted that once the throttle is hit, every attempt to login will
 204                 // generate the log message until the throttle expires, not just the attempt that
 205                 // puts the throttle over the top.
 206                 $this->logger->log( $level, $logMsg, $context );
 207         }
 208
 209 }