Subversion-Projekte lars-tiefland.codeigniter

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP 4.3.2 or newer

 *

 * @package		CodeIgniter

 * @author		ExpressionEngine Dev Team

 * @copyright	Copyright (c) 2008, EllisLab, Inc.

 * @license		http://codeigniter.com/user_guide/license.html

 * @link		http://codeigniter.com

 * @since		Version 1.0

 * @filesource

 */

// ------------------------------------------------------------------------

/**

 * Input Class

 *

 * Pre-processes global input data for security

 *

 * @package		CodeIgniter

 * @subpackage	Libraries

 * @category	Input

 * @author		ExpressionEngine Dev Team

 * @link		http://codeigniter.com/user_guide/libraries/input.html

 */

class CI_Input {

	var $use_xss_clean		= FALSE;

	var $xss_hash			= '';

	var $ip_address			= FALSE;

	var $user_agent			= FALSE;

	var $allow_get_array	= FALSE;

	/* never allowed, string replacement */

	var $never_allowed_str = array(

									'document.cookie'	=> '[removed]',

									'document.write'	=> '[removed]',

									'.parentNode'		=> '[removed]',

									'.innerHTML'		=> '[removed]',

									'window.location'	=> '[removed]',

									'-moz-binding'		=> '[removed]',

									'<!--'				=> '&lt;!--',

									'-->'				=> '-->',

									'<![CDATA['			=> '&lt;![CDATA['

									);

	/* never allowed, regex replacement */

	var $never_allowed_regex = array(

										"javascript\s*:"			=> '[removed]',

										"expression\s*(\(|&\#40;)"	=> '[removed]', // CSS and IE

										"vbscript\s*:"				=> '[removed]', // IE, surprise!

										"Redirect\s+302"			=> '[removed]'

									);

	/**

	* Constructor

	*

	* Sets whether to globally enable the XSS processing

	* and whether to allow the $_GET array

	*

	* @access	public

	*/

	function CI_Input()

	{

		log_message('debug', "Input Class Initialized");

		$CFG =& load_class('Config');

		$this->use_xss_clean	= ($CFG->item('global_xss_filtering') === TRUE) ? TRUE : FALSE;

		$this->allow_get_array	= ($CFG->item('enable_query_strings') === TRUE) ? TRUE : FALSE;

		$this->_sanitize_globals();

	}

	// --------------------------------------------------------------------

	/**

	* Sanitize Globals

	*

	* This function does the following:

	*

	* Unsets $_GET data (if query strings are not enabled)

	*

	* Unsets all globals if register_globals is enabled

	*

	* Standardizes newline characters to \n

	*

	* @access	private

	* @return	void

	*/

	function _sanitize_globals()

	{

		// Would kind of be "wrong" to unset any of these GLOBALS

		$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST', '_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',

							'system_folder', 'application_folder', 'BM', 'EXT', 'CFG', 'URI', 'RTR', 'OUT', 'IN');

		// Unset globals for security.

		// This is effectively the same as register_globals = off

		foreach (array($_GET, $_POST, $_COOKIE, $_SERVER, $_FILES, $_ENV, (isset($_SESSION) && is_array($_SESSION)) ? $_SESSION : array()) as $global)

		{

			if ( ! is_array($global))

			{

				if ( ! in_array($global, $protected))

				{

					unset($GLOBALS[$global]);

				}

			}

			else

			{

				foreach ($global as $key => $val)

				{

					if ( ! in_array($key, $protected))

					{

						unset($GLOBALS[$key]);

					}

					if (is_array($val))

					{

						foreach($val as $k => $v)

						{

							if ( ! in_array($k, $protected))

							{

								unset($GLOBALS[$k]);

							}

						}

					}

				}

			}

		}

		// Is $_GET data allowed? If not we'll set the $_GET to an empty array

		if ($this->allow_get_array == FALSE)

		{

			$_GET = array();

		}

		else

		{

			$_GET = $this->_clean_input_data($_GET);

		}

		// Clean $_POST Data

		$_POST = $this->_clean_input_data($_POST);

		// Clean $_COOKIE Data

		// Also get rid of specially treated cookies that might be set by a server

		// or silly application, that are of no use to a CI application anyway

		// but that when present will trip our 'Disallowed Key Characters' alarm

		// http://www.ietf.org/rfc/rfc2109.txt

		// note that the key names below are single quoted strings, and are not PHP variables

		unset($_COOKIE['$Version']);

		unset($_COOKIE['$Path']);

		unset($_COOKIE['$Domain']);

		$_COOKIE = $this->_clean_input_data($_COOKIE);

		log_message('debug', "Global POST and COOKIE data sanitized");

	}

	// --------------------------------------------------------------------

	/**

	* Clean Input Data

	*

	* This is a helper function. It escapes data and

	* standardizes newline characters to \n

	*

	* @access	private

	* @param	string

	* @return	string

	*/

	function _clean_input_data($str)

	{

		if (is_array($str))

		{

			$new_array = array();

			foreach ($str as $key => $val)

			{

				$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);

			}

			return $new_array;

		}

		// We strip slashes if magic quotes is on to keep things consistent

		if (get_magic_quotes_gpc())

		{

			$str = stripslashes($str);

		}

		// Should we filter the input data?

		if ($this->use_xss_clean === TRUE)

		{

			$str = $this->xss_clean($str);

		}

		// Standardize newlines

		if (strpos($str, "\r") !== FALSE)

		{

			$str = str_replace(array("\r\n", "\r"), "\n", $str);

		}

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	* Clean Keys

	*

	* This is a helper function. To prevent malicious users

	* from trying to exploit keys we make sure that keys are

	* only named with alpha-numeric text and a few other items.

	*

	* @access	private

	* @param	string

	* @return	string

	*/

	function _clean_input_keys($str)

	{

		if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))

		{

			exit('Disallowed Key Characters.');

		}

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	* Fetch from array

	*

	* This is a helper function to retrieve values from global arrays

	*

	* @access	private

	* @param	array

	* @param	string

	* @param	bool

	* @return	string

	*/

	function _fetch_from_array(&$array, $index = '', $xss_clean = FALSE)

	{

		if ( ! isset($array[$index]))

		{

			return FALSE;

		}

		if ($xss_clean === TRUE)

		{

			return $this->xss_clean($array[$index]);

		}

		return $array[$index];

	}

	// --------------------------------------------------------------------

	/**

	* Fetch an item from the GET array

	*

	* @access	public

	* @param	string

	* @param	bool

	* @return	string

	*/

	function get($index = '', $xss_clean = FALSE)

	{

		return $this->_fetch_from_array($_GET, $index, $xss_clean);

	}

	// --------------------------------------------------------------------

	/**

	* Fetch an item from the POST array

	*

	* @access	public

	* @param	string

	* @param	bool

	* @return	string

	*/

	function post($index = '', $xss_clean = FALSE)

	{

		return $this->_fetch_from_array($_POST, $index, $xss_clean);

	}

	// --------------------------------------------------------------------

	/**

	* Fetch an item from either the GET array or the POST

	*

	* @access	public

	* @param	string	The index key

	* @param	bool	XSS cleaning

	* @return	string

	*/

	function get_post($index = '', $xss_clean = FALSE)

	{

		if ( ! isset($_POST[$index]) )

		{

			return $this->get($index, $xss_clean);

		}

		else

		{

			return $this->post($index, $xss_clean);

		}

	}

	// --------------------------------------------------------------------

	/**

	* Fetch an item from the COOKIE array

	*

	* @access	public

	* @param	string

	* @param	bool

	* @return	string

	*/

	function cookie($index = '', $xss_clean = FALSE)

	{

		return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);

	}

	// --------------------------------------------------------------------

	/**

	* Fetch an item from the SERVER array

	*

	* @access	public

	* @param	string

	* @param	bool

	* @return	string

	*/

	function server($index = '', $xss_clean = FALSE)

	{

		return $this->_fetch_from_array($_SERVER, $index, $xss_clean);

	}

	// --------------------------------------------------------------------

	/**

	* Fetch the IP Address

	*

	* @access	public

	* @return	string

	*/

	function ip_address()

	{

		if ($this->ip_address !== FALSE)

		{

			return $this->ip_address;

		}

		if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))

		{

			$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);

			$proxies = is_array($proxies) ? $proxies : array($proxies);

			$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];

		}

		elseif ($this->server('REMOTE_ADDR') AND $this->server('HTTP_CLIENT_IP'))

		{

			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];

		}

		elseif ($this->server('REMOTE_ADDR'))

		{

			$this->ip_address = $_SERVER['REMOTE_ADDR'];

		}

		elseif ($this->server('HTTP_CLIENT_IP'))

		{

			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];

		}

		elseif ($this->server('HTTP_X_FORWARDED_FOR'))

		{

			$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];

		}

		if ($this->ip_address === FALSE)

		{

			$this->ip_address = '0.0.0.0';

			return $this->ip_address;

		}

		if (strstr($this->ip_address, ','))

		{

			$x = explode(',', $this->ip_address);

			$this->ip_address = trim(end($x));

		}

		if ( ! $this->valid_ip($this->ip_address))

		{

			$this->ip_address = '0.0.0.0';

		}

		return $this->ip_address;

	}

	// --------------------------------------------------------------------

	/**

	* Validate IP Address

	*

	* Updated version suggested by Geert De Deckere

	*

	* @access	public

	* @param	string

	* @return	string

	*/

	function valid_ip($ip)

	{

		$ip_segments = explode('.', $ip);

		// Always 4 segments needed

		if (count($ip_segments) != 4)

		{

			return FALSE;

		}

		// IP can not start with 0

		if ($ip_segments[0][0] == '0')

		{

			return FALSE;

		}

		// Check each segment

		foreach ($ip_segments as $segment)

		{

			// IP segments must be digits and can not be

			// longer than 3 digits or greater then 255

			if ($segment == '' OR preg_match("/[^0-9]/", $segment) OR $segment > 255 OR strlen($segment) > 3)

			{

				return FALSE;

			}

		}

		return TRUE;

	}

	// --------------------------------------------------------------------

	/**

	* User Agent

	*

	* @access	public

	* @return	string

	*/

	function user_agent()

	{

		if ($this->user_agent !== FALSE)

		{

			return $this->user_agent;

		}

		$this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];

		return $this->user_agent;

	}

	// --------------------------------------------------------------------

	/**

	* Filename Security

	*

	* @access	public

	* @param	string

	* @return	string

	*/

	function filename_security($str)

	{

		$bad = array(

						"../",

						"./",

						"<!--",

						"-->",

						"<",

						">",

						"'",

						'"',

						'&',

						'$',

						'#',

						'{',

						'}',

						'[',

						']',

						'=',

						';',

						'?',

						"%20",

						"%22",

						"%3c",		// <

						"%253c", 	// <

						"%3e", 		// >

						"%0e", 		// >

						"%28", 		// (

						"%29", 		// )

						"%2528", 	// (

						"%26", 		// &

						"%24", 		// $

						"%3f", 		// ?

						"%3b", 		// ;

						"%3d"		// =

					);

		return stripslashes(str_replace($bad, '', $str));

	}

	// --------------------------------------------------------------------

	/**

	* XSS Clean

	*

	* Sanitizes data so that Cross Site Scripting Hacks can be

	* prevented.  This function does a fair amount of work but

	* it is extremely thorough, designed to prevent even the

	* most obscure XSS attempts.  Nothing is ever 100% foolproof,

	* of course, but I haven't been able to get anything passed

	* the filter.

	*

	* Note: This function should only be used to deal with data

	* upon submission.  It's not something that should

	* be used for general runtime processing.

	*

	* This function was based in part on some code and ideas I

	* got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention

	*

	* To help develop this script I used this great list of

	* vulnerabilities along with a few other hacks I've

	* harvested from examining vulnerabilities in other programs:

	* http://ha.ckers.org/xss.html

	*

	* @access	public

	* @param	string

	* @return	string

	*/

	function xss_clean($str, $is_image = FALSE)

	{

		/*

		* Is the string an array?

		*

		*/

		if (is_array($str))

		{

			while (list($key) = each($str))

			{

				$str[$key] = $this->xss_clean($str[$key]);

			}

			return $str;

		}

		/*

		* Remove Invisible Characters

		*/

		$str = $this->_remove_invisible_characters($str);

		/*

		* Protect GET variables in URLs

		*/

		// 901119URL5918AMP18930PROTECT8198

		$str = preg_replace('|\&([a-z\_0-9]+)\=([a-z\_0-9]+)|i', $this->xss_hash()."\\1=\\2", $str);

		/*

		* Validate standard character entities

		*

		* Add a semicolon if missing.  We do this to enable

		* the conversion of entities to ASCII later.

		*

		*/

		$str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str);

		/*

		* Validate UTF16 two byte encoding (x00)

		*

		* Just as above, adds a semicolon if missing.

		*

		*/

		$str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str);

		/*

		* Un-Protect GET variables in URLs

		*/

		$str = str_replace($this->xss_hash(), '&', $str);

		/*

		* URL Decode

		*

		* Just in case stuff like this is submitted:

		*

		* <a href="http://%77%77%77%2E%67%6F%6F%67%6C%65%2E%63%6F%6D">Google</a>

		*

		* Note: Use rawurldecode() so it does not remove plus signs

		*

		*/

		$str = rawurldecode($str);

		/*

		* Convert character entities to ASCII

		*

		* This permits our tests below to work reliably.

		* We only convert entities that are within tags since

		* these are the ones that will pose security problems.

		*

		*/

		$str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);

		$str = preg_replace_callback("/<\w+.*?(?=>|<|$)/si", array($this, '_html_entity_decode_callback'), $str);

		/*

		* Remove Invisible Characters Again!

		*/

		$str = $this->_remove_invisible_characters($str);

		/*

		* Convert all tabs to spaces

		*

		* This prevents strings like this: ja	vascript

		* NOTE: we deal with spaces between characters later.

		* NOTE: preg_replace was found to be amazingly slow here on large blocks of data,

		* so we use str_replace.

		*

		*/

 		if (strpos($str, "\t") !== FALSE)

		{

			$str = str_replace("\t", ' ', $str);

		}

		/*

		* Capture converted string for later comparison

		*/

		$converted_string = $str;

		/*

		* Not Allowed Under Any Conditions

		*/

		foreach ($this->never_allowed_str as $key => $val)

		{

			$str = str_replace($key, $val, $str);

		}

		foreach ($this->never_allowed_regex as $key => $val)

		{

			$str = preg_replace("#".$key."#i", $val, $str);

		}

		/*

		* Makes PHP tags safe

		*

		*  Note: XML tags are inadvertently replaced too:

		*

		*	<?xml

		*

		* But it doesn't seem to pose a problem.

		*

		*/

		if ($is_image === TRUE)

		{

			// Images have a tendency to have the PHP short opening and closing tags every so often

			// so we skip those and only do the long opening tags.

			$str = str_replace(array('<?php', '<?PHP'),  array('&lt;?php', '&lt;?PHP'), $str);

		}

		else

		{

			$str = str_replace(array('<?php', '<?PHP', '<?', '?'.'>'),  array('&lt;?php', '&lt;?PHP', '&lt;?', '?&gt;'), $str);

		}

		/*

		* Compact any exploded words

		*

		* This corrects words like:  j a v a s c r i p t

		* These words are compacted back to their correct state.

		*

		*/

		$words = array('javascript', 'expression', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');

		foreach ($words as $word)

		{

			$temp = '';

			for ($i = 0, $wordlen = strlen($word); $i < $wordlen; $i++)

			{

				$temp .= substr($word, $i, 1)."\s*";

			}

			// We only want to do this when it is followed by a non-word character

			// That way valid stuff like "dealer to" does not become "dealerto"

			$str = preg_replace_callback('#('.substr($temp, 0, -3).')(\W)#is', array($this, '_compact_exploded_words'), $str);

		}

		/*

		* Remove disallowed Javascript in links or img tags

		* We used to do some version comparisons and use of stripos for PHP5, but it is dog slow compared

		* to these simplified non-capturing preg_match(), especially if the pattern exists in the string

		*/

		do

		{

			$original = $str;

			if (preg_match("/<a/i", $str))

			{

				$str = preg_replace_callback("#<a\s+([^>]*?)(>|$)#si", array($this, '_js_link_removal'), $str);

			}

			if (preg_match("/<img/i", $str))

			{

				$str = preg_replace_callback("#<img\s+([^>]*?)(\s?/?>|$)#si", array($this, '_js_img_removal'), $str);

			}

			if (preg_match("/script/i", $str) OR preg_match("/xss/i", $str))

			{

				$str = preg_replace("#<(/*)(script|xss)(.*?)\>#si", '[removed]', $str);

			}

		}

		while($original != $str);

		unset($original);

		/*

		* Remove JavaScript Event Handlers

		*

		* Note: This code is a little blunt.  It removes

		* the event handler and anything up to the closing >,

		* but it's unlikely to be a problem.

		*

		*/

		$event_handlers = array('[^a-z_\-]on\w*','xmlns');

		if ($is_image === TRUE)

		{

			/*

			* Adobe Photoshop puts XML metadata into JFIF images, including namespacing,

			* so we have to allow this for images. -Paul

			*/

			unset($event_handlers[array_search('xmlns', $event_handlers)]);

		}

		$str = preg_replace("#<([^><]+?)(".implode('|', $event_handlers).")(\s*=\s*[^><]*)([><]*)#i", "<\\1\\4", $str);

		/*

		* Sanitize naughty HTML elements

		*

		* If a tag containing any of the words in the list

		* below is found, the tag gets converted to entities.

		*

		* So this: <blink>

		* Becomes: <blink>

		*

		*/

		$naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|isindex|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';

		$str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);

		/*

		* Sanitize naughty scripting elements

		*

		* Similar to above, only instead of looking for

		* tags it looks for PHP and JavaScript commands

		* that are disallowed.  Rather than removing the

		* code, it simply converts the parenthesis to entities

		* rendering the code un-executable.

		*

		* For example:	eval('some code')

		* Becomes:		eval('some code')

		*

		*/

		$str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2(\\3)", $str);

		/*

		* Final clean up

		*

		* This adds a bit of extra precaution in case

		* something got through the above filters

		*

		*/

		foreach ($this->never_allowed_str as $key => $val)

		{

			$str = str_replace($key, $val, $str);

		}

		foreach ($this->never_allowed_regex as $key => $val)

		{

			$str = preg_replace("#".$key."#i", $val, $str);

		}

		/*

		*  Images are Handled in a Special Way

		*  - Essentially, we want to know that after all of the character conversion is done whether

		*  any unwanted, likely XSS, code was found.  If not, we return TRUE, as the image is clean.

		*  However, if the string post-conversion does not matched the string post-removal of XSS,

		*  then it fails, as there was unwanted XSS code found and removed/changed during processing.

		*/

		if ($is_image === TRUE)

		{

			if ($str == $converted_string)

			{

				return TRUE;

			}

			else

			{

				return FALSE;

			}

		}

		log_message('debug', "XSS Filtering completed");

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	* Random Hash for protecting URLs

	*

	* @access	public

	* @return	string

	*/

	function xss_hash()

	{

		if ($this->xss_hash == '')

		{

			if (phpversion() >= 4.2)

				mt_srand();

			else

				mt_srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff);

			$this->xss_hash = md5(time() + mt_rand(0, 1999999999));

		}

		return $this->xss_hash;

	}

	// --------------------------------------------------------------------

	/**

	* Remove Invisible Characters

	*

	* This prevents sandwiching null characters

	* between ascii characters, like Java\0script.

	*

	* @access	public

	* @param	string

	* @return	string

	*/

	function _remove_invisible_characters($str)

	{

		static $non_displayables;

		if ( ! isset($non_displayables))

		{

			// every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),

			$non_displayables = array(

										'/%0[0-8bcef]/',			// url encoded 00-08, 11, 12, 14, 15

										'/%1[0-9a-f]/',				// url encoded 16-31

										'/[\x00-\x08]/',			// 00-08

										'/\x0b/', '/\x0c/',			// 11, 12

										'/[\x0e-\x1f]/'				// 14-31

									);

		}

		do

		{

			$cleaned = $str;

			$str = preg_replace($non_displayables, '', $str);

		}

		while ($cleaned != $str);

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	* Compact Exploded Words

	*

	* Callback function for xss_clean() to remove whitespace from

	* things like j a v a s c r i p t

	*

	* @access	public

	* @param	type

	* @return	type

	*/

	function _compact_exploded_words($matches)

	{

		return preg_replace('/\s+/s', '', $matches[1]).$matches[2];

	}

	// --------------------------------------------------------------------

	/**

	* Sanitize Naughty HTML

	*

	* Callback function for xss_clean() to remove naughty HTML elements

	*

	* @access	private

	* @param	array

	* @return	string

	*/

	function _sanitize_naughty_html($matches)

	{

		// encode opening brace

		$str = '<'.$matches[1].$matches[2].$matches[3];

		// encode captured opening or closing brace to prevent recursive vectors

		$str .= str_replace(array('>', '<'), array('&gt;', '&lt;'), $matches[4]);

		return $str;

	}

	// --------------------------------------------------------------------

	/**

	* JS Link Removal

	*

	* Callback function for xss_clean() to sanitize links

	* This limits the PCRE backtracks, making it more performance friendly

	* and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in

	* PHP 5.2+ on link-heavy strings

	*

	* @access	private

	* @param	array

	* @return	string

	*/

	function _js_link_removal($match)

	{

		$attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));

		return str_replace($match[1], preg_replace("#href=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);

	}

	/**

	* JS Image Removal

	*

	* Callback function for xss_clean() to sanitize image tags

	* This limits the PCRE backtracks, making it more performance friendly

	* and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in

	* PHP 5.2+ on image tag heavy strings

	*

	* @access	private

	* @param	array

	* @return	string

	*/

	function _js_img_removal($match)

	{

		$attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));

		return str_replace($match[1], preg_replace("#src=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);

	}

	// --------------------------------------------------------------------

	/**

	* Attribute Conversion

	*

	* Used as a callback for XSS Clean

	*

	* @access	public

	* @param	array

	* @return	string

	*/

	function _convert_attribute($match)

	{

		return str_replace(array('>', '<', '\\'), array('&gt;', '&lt;', '\\\\'), $match[0]);

	}

	// --------------------------------------------------------------------

	/**

	* HTML Entity Decode Callback

	*

	* Used as a callback for XSS Clean

	*

	* @access	public

	* @param	array

	* @return	string

	*/

	function _html_entity_decode_callback($match)

	{

		$CFG =& load_class('Config');

		$charset = $CFG->item('charset');

		return $this->_html_entity_decode($match[0], strtoupper($charset));

	}

	// --------------------------------------------------------------------

	/**

	* HTML Entities Decode

	*

	* This function is a replacement for html_entity_decode()

	*

	* In some versions of PHP the native function does not work

	* when UTF-8 is the specified character set, so this gives us

	* a work-around.  More info here:

	* http://bugs.php.net/bug.php?id=25670

	*

	* @access	private

	* @param	string

	* @param	string

	* @return	string

	*/

	/* -------------------------------------------------

	/*  Replacement for html_entity_decode()

	/* -------------------------------------------------*/

	/*

	NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the