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RateLimiter.php
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RateLimiter.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
*/
namespace MediaWiki\Permissions;
use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\User\CentralId\CentralIdLookup;
use MediaWiki\User\UserFactory;
use MediaWiki\User\UserGroupManager;
use Psr\Log\LoggerInterface;
use Wikimedia\IPUtils;
use Wikimedia\Stats\NullStatsdDataFactory;
use Wikimedia\WRStats\LimitCondition;
use Wikimedia\WRStats\WRStatsFactory;
/**
* Provides rate limiting for a set of actions based on several counter
* buckets.
*
* @since 1.39
*/
class RateLimiter {
private LoggerInterface $logger;
private StatsdDataFactoryInterface $stats;
private ServiceOptions $options;
private WRStatsFactory $wrstatsFactory;
private ?CentralIdLookup $centralIdLookup;
private UserFactory $userFactory;
private UserGroupManager $userGroupManager;
private HookContainer $hookContainer;
private HookRunner $hookRunner;
/** @var array */
private $rateLimits;
/**
* Actions that are exempt from all rate limiting.
*
* Actions listed here will bypass all rate limiting,
* including limits implemented in hooks.
*
* This serves as a performance optimization, to avoid overhead for actions
* that are performed a lot and have no need to be limited.
*
* @note This is currently hard-coded to contain just the 'read' action.
* It can be made configurable to extended to include more actions if needed.
*
* @var array<string,bool>
*/
private array $nonLimitableActions = [
'read' => true,
];
/**
* @internal
*/
public const CONSTRUCTOR_OPTIONS = [
MainConfigNames::RateLimits,
MainConfigNames::RateLimitsExcludedIPs,
];
public function __construct(
ServiceOptions $options,
WRStatsFactory $wrstatsFactory,
?CentralIdLookup $centralIdLookup,
UserFactory $userFactory,
UserGroupManager $userGroupManager,
HookContainer $hookContainer
) {
$this->logger = LoggerFactory::getInstance( 'ratelimit' );
$this->stats = new NullStatsdDataFactory();
$options->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
$this->options = $options;
$this->wrstatsFactory = $wrstatsFactory;
$this->centralIdLookup = $centralIdLookup;
$this->userFactory = $userFactory;
$this->userGroupManager = $userGroupManager;
$this->hookContainer = $hookContainer;
$this->hookRunner = new HookRunner( $hookContainer );
$this->rateLimits = $this->options->get( MainConfigNames::RateLimits );
}
public function setStats( StatsdDataFactoryInterface $stats ) {
$this->stats = $stats;
}
private function incrementStats( $name ) {
$this->stats->increment( "RateLimiter.$name" );
}
/**
* Is this user exempt from rate limiting?
*
* @param RateLimitSubject $subject The subject of the rate limit, representing the
* client performing the action.
*
* @return bool
*/
public function isExempt( RateLimitSubject $subject ) {
$rateLimitsExcludedIPs = $this->options->get( MainConfigNames::RateLimitsExcludedIPs );
$ip = $subject->getIP();
if ( $ip && IPUtils::isInRanges( $ip, $rateLimitsExcludedIPs ) ) {
return true;
}
// NOTE: To avoid circular dependencies, we rely on a flag here rather than using an
// Authority instance to check the permission. Using PermissionManager might work,
// but keeping cross-dependencies to a minimum seems best. The code that constructs
// the RateLimitSubject should know where to get the relevant info.
return $subject->is( RateLimitSubject::EXEMPT );
}
/**
* Checks whether the given action may be limited.
* Can be used for optimization, to avoid calling limit() if we can know in advance that no limit will apply.
*
* @param string $action
*
* @return bool
*/
public function isLimitable( $action ) {
// Bypass limit checks for actions that are defined to be non-limitable.
// This is a performance optimization.
if ( $this->nonLimitableActions[$action] ?? false ) {
return false;
}
if ( isset( $this->rateLimits[$action] ) ) {
return true;
}
if ( $this->hookContainer->isRegistered( 'PingLimiter' ) ) {
return true;
}
return false;
}
/**
* Implements simple rate limits: enforce maximum actions per time period
* to put a brake on flooding.
*
* @note This method will always return false for any action listed in
* $this->nonLimitableActions. This allows rate limit checks to
* be bypassed for certain actions to avoid overhead and improve
* performance.
*
* @param RateLimitSubject $subject The subject of the rate limit, representing the
* client performing the action.
* @param string $action Action to enforce
* @param int $incrBy Positive amount to increment counter by, 1 by default.
* Use 0 to check the limit without bumping the counter.
*
* @return bool True if a rate limit was exceeded.
*/
public function limit( RateLimitSubject $subject, string $action, int $incrBy = 1 ) {
// Bypass limit checks for actions that are defined to be non-limitable.
// This is a performance optimization.
if ( $this->nonLimitableActions[$action] ?? false ) {
return false;
}
$user = $subject->getUser();
$ip = $subject->getIP();
// Call the 'PingLimiter' hook
$result = false;
$legacyUser = $this->userFactory->newFromUserIdentity( $user );
if ( !$this->hookRunner->onPingLimiter( $legacyUser, $action, $result, $incrBy ) ) {
$this->incrementStats( "limit.$action.result." . ( $result ? 'tripped_by_hook' : 'passed_by_hook' ) );
return $result;
}
if ( !isset( $this->rateLimits[$action] ) ) {
return false;
}
// Some groups shouldn't trigger the ping limiter, ever
if ( $this->canBypass( $action ) && $this->isExempt( $subject ) ) {
$this->incrementStats( "limit.$action.result.exempt" );
return false;
}
$conds = $this->getConditions( $action );
$limiter = $this->wrstatsFactory->createRateLimiter( $conds, [ 'limiter', $action ] );
$peekMode = $incrBy === 0;
$limitBatch = $limiter->createBatch( $incrBy ?: 1 );
$this->logger->debug( __METHOD__ . ": limiting $action rate for {$user->getName()}" );
$id = $user->getId();
$isNewbie = $subject->is( RateLimitSubject::NEWBIE );
if ( $id == 0 ) {
// "shared anon" limit, for all anons combined
if ( isset( $conds['anon'] ) ) {
$limitBatch->localOp( 'anon', [] );
}
} else {
// "global per name" limit, across sites
if ( isset( $conds['user-global'] ) ) {
$centralId = $this->centralIdLookup
? $this->centralIdLookup->centralIdFromLocalUser( $user, CentralIdLookup::AUDIENCE_RAW )
: 0;
if ( $centralId ) {
// We don't have proper realms, use provider ID.
$realm = $this->centralIdLookup->getProviderId();
$limitBatch->globalOp( 'user-global', [ $realm, $centralId ] );
} else {
// Fall back to a local key for a local ID
$limitBatch->localOp( 'user-global', [ 'local', $id ] );
}
}
}
if ( $isNewbie && $ip ) {
// "per ip" limit for anons and newbie users
if ( isset( $conds['ip'] ) ) {
$limitBatch->globalOp( 'ip', $ip );
}
// "per subnet" limit for anons and newbie users
if ( isset( $conds['subnet'] ) ) {
$subnet = IPUtils::getSubnet( $ip );
if ( $subnet !== false ) {
$limitBatch->globalOp( 'subnet', $subnet );
}
}
}
// determine the "per user account" limit
$userEntityType = false;
if ( $id !== 0 && isset( $conds['user'] ) ) {
// default limit for logged-in users
$userEntityType = 'user';
}
// limits for newbie logged-in users (overrides all the normal user limits)
if ( $id !== 0 && $isNewbie && isset( $conds['newbie'] ) ) {
$userEntityType = 'newbie';
} else {
// Check for group-specific limits
// If more than one group applies, use the highest allowance (if higher than the default)
$userGroups = $this->userGroupManager->getUserGroups( $user );
foreach ( $userGroups as $group ) {
if ( isset( $conds[$group] ) ) {
if ( $userEntityType === false
|| $conds[$group]->perSecond() > $conds[$userEntityType]->perSecond()
) {
$userEntityType = $group;
}
}
}
}
// Set the user limit key
if ( $userEntityType !== false ) {
$limitBatch->localOp( $userEntityType, $id );
}
// ip-based limits for all ping-limitable users
if ( isset( $conds['ip-all'] ) && $ip ) {
// ignore if user limit is more permissive
if ( $isNewbie || $userEntityType === false
|| $conds['ip-all']->perSecond() > $conds[$userEntityType]->perSecond()
) {
$limitBatch->globalOp( 'ip-all', $ip );
}
}
// subnet-based limits for all ping-limitable users
if ( isset( $conds['subnet-all'] ) && $ip ) {
$subnet = IPUtils::getSubnet( $ip );
if ( $subnet !== false ) {
// ignore if user limit is more permissive
if ( $isNewbie || $userEntityType === false
|| $conds['ip-all']->perSecond() > $conds[$userEntityType]->perSecond()
) {
$limitBatch->globalOp( 'subnet-all', $subnet );
}
}
}
$loggerInfo = [
'name' => $user->getName(),
'ip' => $ip,
];
$batchResult = $peekMode ? $limitBatch->peek() : $limitBatch->tryIncr();
foreach ( $batchResult->getFailedResults() as $type => $result ) {
$this->logger->info(
'User::pingLimiter: User tripped rate limit',
[
'action' => $action,
'limit' => $result->condition->limit,
'period' => $result->condition->window,
'count' => $result->prevTotal,
'key' => $type
] + $loggerInfo
);
$this->incrementStats( "limit.$action.tripped_by.$type" );
}
$allowed = $batchResult->isAllowed();
$this->incrementStats( "limit.$action.result." . ( $allowed ? 'passed' : 'tripped' ) );
return !$allowed;
}
private function canBypass( string $action ) {
return $this->rateLimits[$action]['&can-bypass'] ?? true;
}
/**
* @param string $action
* @return LimitCondition[]
*/
private function getConditions( $action ) {
if ( !isset( $this->rateLimits[$action] ) ) {
return [];
}
$conds = [];
foreach ( $this->rateLimits[$action] as $entityType => $limitInfo ) {
if ( $entityType[0] === '&' ) {
continue;
}
[ $limit, $window ] = $limitInfo;
$conds[$entityType] = new LimitCondition(
$limit,
$window
);
}
return $conds;
}
}

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text/x-php
Expires
Sat, May 16, 14:43 (1 d, 1 h)
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local-disk
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Storage Handle
6e/a8/349edaec4de0eddeb576dfaff16f
Default Alt Text
RateLimiter.php (10 KB)

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