143 lines
3.4 KiB
PHP
143 lines
3.4 KiB
PHP
<?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
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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 $limit
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* @return void
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*/
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public static function setLimit($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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* @return void
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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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