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<?php |
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/** |
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* PrivateBin |
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* |
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* a zero-knowledge paste bin |
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* |
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* @link https://github.com/PrivateBin/PrivateBin |
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* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net) |
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* @license https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License |
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* @version 1.1.1 |
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*/ |
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namespace PrivateBin\Persistence; |
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use PrivateBin\Configuration; |
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/** |
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* TrafficLimiter |
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* |
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* Handles traffic limiting, so no user does more than one call per 10 seconds. |
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*/ |
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class TrafficLimiter extends AbstractPersistence |
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{ |
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/** |
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* time limit in seconds, defaults to 10s |
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* |
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* @access private |
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* @static |
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* @var int |
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*/ |
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private static $_limit = 10; |
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/** |
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* key to fetch IP address |
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* |
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* @access private |
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* @static |
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* @var string |
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*/ |
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private static $_ipKey = 'REMOTE_ADDR'; |
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/** |
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* set the time limit in seconds |
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* |
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* @access public |
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* @static |
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* @param int $limit |
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*/ |
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public static function setLimit($limit) |
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{ |
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self::$_limit = $limit; |
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} |
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/** |
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* set configuration options of the traffic limiter |
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* |
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* @access public |
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* @static |
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* @param Configuration $conf |
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*/ |
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public static function setConfiguration(Configuration $conf) |
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{ |
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self::setLimit($conf->getKey('limit', 'traffic')); |
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self::setPath($conf->getKey('dir', 'traffic')); |
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if (($option = $conf->getKey('header', 'traffic')) !== null) { |
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$httpHeader = 'HTTP_' . $option; |
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if (array_key_exists($httpHeader, $_SERVER) && !empty($_SERVER[$httpHeader])) { |
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self::$_ipKey = $httpHeader; |
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} |
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} |
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} |
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/** |
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* get a HMAC of the current visitors IP address |
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* |
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* @access public |
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* @static |
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* @param string $algo |
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* @return string |
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*/ |
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public static function getHash($algo = 'sha512') |
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{ |
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return hash_hmac($algo, $_SERVER[self::$_ipKey], ServerSalt::get()); |
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} |
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/** |
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* traffic limiter |
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* |
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* Make sure the IP address makes at most 1 request every 10 seconds. |
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* |
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* @access public |
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* @static |
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* @throws Exception |
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* @return bool |
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*/ |
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public static function canPass() |
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{ |
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// disable limits if set to less then 1 |
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if (self::$_limit < 1) { |
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return true; |
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} |
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$file = 'traffic_limiter.php'; |
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if (!self::_exists($file)) { |
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self::_store( |
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$file, |
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'<?php' . PHP_EOL . |
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'$GLOBALS[\'traffic_limiter\'] = array();' . PHP_EOL |
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); |
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} |
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$path = self::getPath($file); |
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require $path; |
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$now = time(); |
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$tl = $GLOBALS['traffic_limiter']; |
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// purge file of expired hashes to keep it small |
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foreach ($tl as $key => $time) { |
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if ($time + self::$_limit < $now) { |
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unset($tl[$key]); |
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} |
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} |
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// this hash is used as an array key, hence a shorter hash is used |
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$hash = self::getHash('sha256'); |
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if (array_key_exists($hash, $tl) && ($tl[$hash] + self::$_limit >= $now)) { |
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$result = false; |
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} else { |
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$tl[$hash] = time(); |
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$result = true; |
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} |
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self::_store( |
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$file, |
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'<?php' . PHP_EOL . |
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'$GLOBALS[\'traffic_limiter\'] = ' . |
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var_export($tl, true) . ';' . PHP_EOL |
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); |
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return $result; |
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} |
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} |
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Instead of super-globals, we recommend to explicitly inject the dependencies of your class. This makes your code less dependent on global state and it becomes generally more testable: