109 lines
4.7 KiB
PHP
109 lines
4.7 KiB
PHP
<?php defined('SYSPATH') OR die('No direct access allowed.');
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/**
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* Security helper class.
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*
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* @package Core
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* @author Kohana Team
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* @copyright (c) 2007-2009 Kohana Team
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* @license http://kohanaphp.com/license.html
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*/
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class security_Core {
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/**
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* Remove XSS from user input.
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*
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* @author Christian Stocker <chregu@bitflux.ch>
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* @copyright (c) 2001-2006 Bitflux GmbH
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*
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* @param string string to sanitize
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* @return string
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*/
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public static function xss_clean($str)
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{
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// http://svn.bitflux.ch/repos/public/popoon/trunk/classes/externalinput.php
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// +----------------------------------------------------------------------+
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// | Copyright (c) 2001-2006 Bitflux GmbH |
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// +----------------------------------------------------------------------+
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// | Licensed under the Apache License, Version 2.0 (the "License"); |
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// | you may not use this file except in compliance with the License. |
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// | You may obtain a copy of the License at |
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// | http://www.apache.org/licenses/LICENSE-2.0 |
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// | Unless required by applicable law or agreed to in writing, software |
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// | distributed under the License is distributed on an "AS IS" BASIS, |
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// | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
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// | implied. See the License for the specific language governing |
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// | permissions and limitations under the License. |
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// +----------------------------------------------------------------------+
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// | Author: Christian Stocker <chregu@bitflux.ch> |
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// +----------------------------------------------------------------------+
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//
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// Kohana Modifications:
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// * Changed double quotes to single quotes, changed indenting and spacing
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// * Removed magic_quotes stuff
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// * Increased regex readability:
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// * Used delimeters that aren't found in the pattern
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// * Removed all unneeded escapes
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// * Deleted U modifiers and swapped greediness where needed
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// * Increased regex speed:
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// * Made capturing parentheses non-capturing where possible
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// * Removed parentheses where possible
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// * Split up alternation alternatives
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// * Made some quantifiers possessive
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// Fix &entity\n;
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$data = str_replace(array('&','<','>'), array('&amp;','&lt;','&gt;'), $data);
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$data = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $data);
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$data = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $data);
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$data = html_entity_decode($data, ENT_COMPAT, Kohana::$charset);
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// Remove any attribute starting with "on" or xmlns
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$data = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $data);
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// Remove javascript: and vbscript: protocols
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$data = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $data);
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$data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $data);
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$data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $data);
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// Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
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$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
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$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
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$data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $data);
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// Remove namespaced elements (we do not need them)
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$data = preg_replace('#</*\w+:\w[^>]*+>#i', '', $data);
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do
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{
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// Remove really unwanted tags
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$old_data = $data;
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$data = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $data);
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}
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while ($old_data !== $data);
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return $data;
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}
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/**
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* Remove image tags from a string.
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*
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* @param string string to sanitize
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* @return string
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*/
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public static function strip_image_tags($str)
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{
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return preg_replace('#<img\s.*?(?:src\s*=\s*["\']?([^"\'<>\s]*)["\']?[^>]*)?>#is', '$1', $str);
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}
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/**
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* Remove PHP tags from a string.
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*
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* @param string string to sanitize
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* @return string
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*/
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public static function encode_php_tags($str)
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{
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return str_replace(array('<?', '?>'), array('<?', '?>'), $str);
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}
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} // End security
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