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| 1 | <?php |
| 2 | |
| 3 | namespace MediaWiki\Extension\AbuseFilter\Watcher; |
| 4 | |
| 5 | use InvalidArgumentException; |
| 6 | use MediaWiki\Config\ServiceOptions; |
| 7 | use MediaWiki\Deferred\AutoCommitUpdate; |
| 8 | use MediaWiki\Deferred\DeferredUpdates; |
| 9 | use MediaWiki\Extension\AbuseFilter\EchoNotifier; |
| 10 | use MediaWiki\Extension\AbuseFilter\EmergencyCache; |
| 11 | use MediaWiki\Extension\AbuseFilter\FilterLookup; |
| 12 | use Wikimedia\Rdbms\IDatabase; |
| 13 | use Wikimedia\Rdbms\LBFactory; |
| 14 | |
| 15 | /** |
| 16 | * Service for monitoring filters with restricted actions and preventing them |
| 17 | * from executing destructive actions ("throttling") |
| 18 | * |
| 19 | * @todo We should log throttling somewhere |
| 20 | */ |
| 21 | class EmergencyWatcher implements Watcher { |
| 22 | public const SERVICE_NAME = 'AbuseFilterEmergencyWatcher'; |
| 23 | |
| 24 | public const CONSTRUCTOR_OPTIONS = [ |
| 25 | 'AbuseFilterEmergencyDisableAge', |
| 26 | 'AbuseFilterEmergencyDisableCount', |
| 27 | 'AbuseFilterEmergencyDisableThreshold', |
| 28 | ]; |
| 29 | |
| 30 | /** @var EmergencyCache */ |
| 31 | private $cache; |
| 32 | |
| 33 | /** @var LBFactory */ |
| 34 | private $lbFactory; |
| 35 | |
| 36 | /** @var FilterLookup */ |
| 37 | private $filterLookup; |
| 38 | |
| 39 | /** @var EchoNotifier */ |
| 40 | private $notifier; |
| 41 | |
| 42 | /** @var ServiceOptions */ |
| 43 | private $options; |
| 44 | |
| 45 | /** |
| 46 | * @param EmergencyCache $cache |
| 47 | * @param LBFactory $lbFactory |
| 48 | * @param FilterLookup $filterLookup |
| 49 | * @param EchoNotifier $notifier |
| 50 | * @param ServiceOptions $options |
| 51 | */ |
| 52 | public function __construct( |
| 53 | EmergencyCache $cache, |
| 54 | LBFactory $lbFactory, |
| 55 | FilterLookup $filterLookup, |
| 56 | EchoNotifier $notifier, |
| 57 | ServiceOptions $options |
| 58 | ) { |
| 59 | $options->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS ); |
| 60 | $this->cache = $cache; |
| 61 | $this->lbFactory = $lbFactory; |
| 62 | $this->filterLookup = $filterLookup; |
| 63 | $this->notifier = $notifier; |
| 64 | $this->options = $options; |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Determine which filters must be throttled, i.e. their potentially dangerous |
| 69 | * actions must be disabled. |
| 70 | * |
| 71 | * @param int[] $filters The filters to check |
| 72 | * @param string $group Group the filters belong to |
| 73 | * @return int[] Array of filters to be throttled |
| 74 | */ |
| 75 | public function getFiltersToThrottle( array $filters, string $group ): array { |
| 76 | $filters = array_intersect( |
| 77 | $filters, |
| 78 | $this->cache->getFiltersToCheckInGroup( $group ) |
| 79 | ); |
| 80 | if ( $filters === [] ) { |
| 81 | return []; |
| 82 | } |
| 83 | |
| 84 | $threshold = $this->getEmergencyValue( 'threshold', $group ); |
| 85 | $hitCountLimit = $this->getEmergencyValue( 'count', $group ); |
| 86 | $maxAge = $this->getEmergencyValue( 'age', $group ); |
| 87 | |
| 88 | $time = (int)wfTimestamp( TS_UNIX ); |
| 89 | |
| 90 | $throttleFilters = []; |
| 91 | foreach ( $filters as $filter ) { |
| 92 | $filterObj = $this->filterLookup->getFilter( $filter, false ); |
| 93 | // TODO: consider removing the filter from the group key |
| 94 | // after throttling |
| 95 | if ( $filterObj->isThrottled() ) { |
| 96 | continue; |
| 97 | } |
| 98 | |
| 99 | $filterAge = (int)wfTimestamp( TS_UNIX, $filterObj->getTimestamp() ); |
| 100 | $exemptTime = $filterAge + $maxAge; |
| 101 | |
| 102 | // Optimize for the common case when filters are well-established |
| 103 | // This check somewhat duplicates the role of cache entry's TTL |
| 104 | // and could as well be removed |
| 105 | if ( $exemptTime <= $time ) { |
| 106 | continue; |
| 107 | } |
| 108 | |
| 109 | // TODO: this value might be stale, there is no guarantee the match |
| 110 | // has actually been recorded now |
| 111 | $cacheValue = $this->cache->getForFilter( $filter ); |
| 112 | if ( $cacheValue === false ) { |
| 113 | continue; |
| 114 | } |
| 115 | |
| 116 | [ 'total' => $totalActions, 'matches' => $matchCount ] = $cacheValue; |
| 117 | |
| 118 | if ( $matchCount > $hitCountLimit && ( $matchCount / $totalActions ) > $threshold ) { |
| 119 | // More than AbuseFilterEmergencyDisableCount matches, constituting more than |
| 120 | // AbuseFilterEmergencyDisableThreshold (a fraction) of last few edits. |
| 121 | // Disable it. |
| 122 | $throttleFilters[] = $filter; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | return $throttleFilters; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Determine which a filters must be throttled and apply the throttling |
| 131 | * |
| 132 | * @inheritDoc |
| 133 | */ |
| 134 | public function run( array $localFilters, array $globalFilters, string $group ): void { |
| 135 | $throttleFilters = $this->getFiltersToThrottle( $localFilters, $group ); |
| 136 | if ( !$throttleFilters ) { |
| 137 | return; |
| 138 | } |
| 139 | |
| 140 | DeferredUpdates::addUpdate( |
| 141 | new AutoCommitUpdate( |
| 142 | $this->lbFactory->getPrimaryDatabase(), |
| 143 | __METHOD__, |
| 144 | static function ( IDatabase $dbw, $fname ) use ( $throttleFilters ) { |
| 145 | $dbw->newUpdateQueryBuilder() |
| 146 | ->update( 'abuse_filter' ) |
| 147 | ->set( [ 'af_throttled' => 1 ] ) |
| 148 | ->where( [ 'af_id' => $throttleFilters ] ) |
| 149 | ->caller( $fname ) |
| 150 | ->execute(); |
| 151 | } |
| 152 | ) |
| 153 | ); |
| 154 | DeferredUpdates::addCallableUpdate( function () use ( $throttleFilters ) { |
| 155 | foreach ( $throttleFilters as $filter ) { |
| 156 | $this->notifier->notifyForFilter( $filter ); |
| 157 | } |
| 158 | } ); |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * @param string $type The value to get, either "threshold", "count" or "age" |
| 163 | * @param string $group The filter's group (as defined in $wgAbuseFilterValidGroups) |
| 164 | * @return mixed |
| 165 | */ |
| 166 | private function getEmergencyValue( string $type, string $group ) { |
| 167 | switch ( $type ) { |
| 168 | case 'threshold': |
| 169 | $opt = 'AbuseFilterEmergencyDisableThreshold'; |
| 170 | break; |
| 171 | case 'count': |
| 172 | $opt = 'AbuseFilterEmergencyDisableCount'; |
| 173 | break; |
| 174 | case 'age': |
| 175 | $opt = 'AbuseFilterEmergencyDisableAge'; |
| 176 | break; |
| 177 | default: |
| 178 | // @codeCoverageIgnoreStart |
| 179 | throw new InvalidArgumentException( '$type must be either "threshold", "count" or "age"' ); |
| 180 | // @codeCoverageIgnoreEnd |
| 181 | } |
| 182 | |
| 183 | $value = $this->options->get( $opt ); |
| 184 | return $value[$group] ?? $value['default']; |
| 185 | } |
| 186 | } |