Security
› Kohana_Security

Class Contents

Class declared in SYSPATH/classes/security.php on line 3.

Properties

Methods

public static function check($token)
{
	return Security::token() === $token;
}

public static function encode_php_tags($str)
{
	return str_replace(array('<?', '?>'), array('&lt;?', '?&gt;'), $str);
}

public static function strip_image_tags($str)
{
	return preg_replace('#<img\s.*?(?:src\s*=\s*["\']?([^"\'<>\s]*)["\']?[^>]*)?>#is', '$1', $str);
}

public static function token($new = FALSE)
{
	$session = Session::instance();

	// Get the current token
	$token = $session->get(Security::$token_name);

	if ($new === TRUE OR ! $token)
	{
		// Generate a new unique token
		$token = uniqid('security');

		// Store the new token
		$session->set(Security::$token_name, $token);
	}

	return $token;
}

public static function xss_clean($str)
{
	// http://svn.bitflux.ch/repos/public/popoon/trunk/classes/externalinput.php
	// +----------------------------------------------------------------------+
	// | Copyright (c) 2001-2006 Bitflux GmbH                                 |
	// +----------------------------------------------------------------------+
	// | Licensed under the Apache License, Version 2.0 (the "License");      |
	// | you may not use this file except in compliance with the License.     |
	// | You may obtain a copy of the License at                              |
	// | http://www.apache.org/licenses/LICENSE-2.0                           |
	// | Unless required by applicable law or agreed to in writing, software  |
	// | distributed under the License is distributed on an "AS IS" BASIS,    |
	// | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or      |
	// | implied. See the License for the specific language governing         |
	// | permissions and limitations under the License.                       |
	// +----------------------------------------------------------------------+
	// | Author: Christian Stocker <chregu@bitflux.ch>                        |
	// +----------------------------------------------------------------------+
	//
	// Kohana Modifications:
	// * Changed double quotes to single quotes, changed indenting and spacing
	// * Removed magic_quotes stuff
	// * Increased regex readability:
	//   * Used delimeters that aren't found in the pattern
	//   * Removed all unneeded escapes
	//   * Deleted U modifiers and swapped greediness where needed
	// * Increased regex speed:
	//   * Made capturing parentheses non-capturing where possible
	//   * Removed parentheses where possible
	//   * Split up alternation alternatives
	//   * Made some quantifiers possessive
	// * Handle arrays recursively

	if (is_array($str) OR is_object($str))
	{
		foreach ($str as $k => $s)
		{
			$str[$k] = Security::xss_clean($s);
		}

		return $str;
	}

	// Remove all NULL bytes
	$str = str_replace("\0", '', $str);

	// Fix &entity\n;
	$str = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $str);
	$str = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $str);
	$str = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $str);
	$str = html_entity_decode($str, ENT_COMPAT, Kohana::$charset);

	// Remove any attribute starting with "on" or xmlns
	$str = preg_replace('#(?:on[a-z]+|xmlns)\s*=\s*[\'"\x00-\x20]?[^\'>"]*[\'"\x00-\x20]?\s?#iu', '', $str);

	// Remove javascript: and vbscript: protocols
	$str = 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...', $str);
	$str = 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...', $str);
	$str = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $str);

	// Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
	$str = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#is', '$1>', $str);
	$str = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#is', '$1>', $str);
	$str = 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]*:*[^>]*+>#ius', '$1>', $str);

	// Remove namespaced elements (we do not need them)
	$str = preg_replace('#</*\w+:\w[^>]*+>#i', '', $str);

	do
	{
		// Remove really unwanted tags
		$old = $str;
		$str = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $str);
	}
	while ($old !== $str);

	return $str;
}