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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 );
}
}
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