Initial commit

Signed-off-by: Florian Pritz <bluewind@xssn.at>

1 files changed, 1067 insertions, 0 deletions

diff --git a/system/libraries/Input.php b/system/libraries/Input.php
new file mode 100644
index 000000000..e7bf72779
--- /dev/null
+++ b/system/libraries/Input.php
@@ -0,0 +1,1067 @@
+<?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 - 2009, 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;!--',
+									'-->'				=> '--&gt;',
+									'<![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 = preg_replace('/<\?(php)/i', "&lt;?\\1", $str);
+		}
+		else
+		{
+			$str = str_replace(array('<?', '?'.'>'),  array('&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: &lt;blink&gt;
+		*
+		*/
+		$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&#40;'some code'&#41;
+		*
+		*/
+		$str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);
+
+		/*
+		* Final clean up
+		*
+		* This adds a bit of extra precaution in case
+		* something got through the above filters
+		*
+		*/
+		foreach ($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
+		$str = '&lt;'.$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($charset));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	* HTML Entities Decode
+	*
+	* This function is a replacement for html_entity_decode()
+	*
+	* In some versions of PHP the native function does not work
+	* when UTF-8 is the specified character set, so this gives us
+	* a work-around.  More info here:
+	* http://bugs.php.net/bug.php?id=25670
+	*
+	* @access	private
+	* @param	string
+	* @param	string
+	* @return	string
+	*/
+	/* -------------------------------------------------
+	/*  Replacement for html_entity_decode()
+	/* -------------------------------------------------*/
+
+	/*
+	NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
+	character set, and the PHP developers said they were not back porting the
+	fix to versions other than PHP 5.x.
+	*/
+	function _html_entity_decode($str, $charset='UTF-8')
+	{
+		if (stristr($str, '&') === FALSE) return $str;
+
+		// The reason we are not using html_entity_decode() by itself is because
+		// while it is not technically correct to leave out the semicolon
+		// at the end of an entity most browsers will still interpret the entity
+		// correctly.  html_entity_decode() does not convert entities without
+		// semicolons, so we are left with our own little solution here. Bummer.
+
+		if (function_exists('html_entity_decode') && (strtolower($charset) != 'utf-8' OR version_compare(phpversion(), '5.0.0', '>=')))
+		{
+			$str = html_entity_decode($str, ENT_COMPAT, $charset);
+			$str = preg_replace('~&#x(0*[0-9a-f]{2,5})~ei', 'chr(hexdec("\\1"))', $str);
+			return preg_replace('~&#([0-9]{2,4})~e', 'chr(\\1)', $str);
+		}
+
+		// Numeric Entities
+		$str = preg_replace('~&#x(0*[0-9a-f]{2,5});{0,1}~ei', 'chr(hexdec("\\1"))', $str);
+		$str = preg_replace('~&#([0-9]{2,4});{0,1}~e', 'chr(\\1)', $str);
+
+		// Literal Entities - Slightly slow so we do another check
+		if (stristr($str, '&') === FALSE)
+		{
+			$str = strtr($str, array_flip(get_html_translation_table(HTML_ENTITIES)));
+		}
+
+		return $str;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	* Filter Attributes
+	*
+	* Filters tag attributes for consistency and safety
+	*
+	* @access	public
+	* @param	string
+	* @return	string
+	*/
+	function _filter_attributes($str)
+	{
+		$out = '';
+
+		if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches))
+		{
+			foreach ($matches[0] as $match)
+			{
+				$out .= preg_replace("#/\*.*?\*/#s", '', $match);
+			}
+		}
+
+		return $out;
+	}
+
+	// --------------------------------------------------------------------
+
+}
+// END Input class
+
+/* End of file Input.php */
+/* Location: ./system/libraries/Input.php */
\ No newline at end of file