input.php

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<?php
/**
 * @version		$Id: input.php 8180 2007-07-23 05:52:29Z eddieajau $
 * @package		Joomla.Framework
 * @subpackage	Filter
 * @copyright	Copyright (C) 2005 - 2007 Open Source Matters. All rights reserved.
 * @license		GNU/GPL, see LICENSE.php
 * Joomla! is free software. This version may have been modified pursuant to the
 * GNU General Public License, and as distributed it includes or is derivative
 * of works licensed under the GNU General Public License or other free or open
 * source software licenses. See COPYRIGHT.php for copyright notices and
 * details.
 */

// Check to ensure this file is within the rest of the framework
defined('JPATH_BASE') or die();

/**
 * JFilterInout is a class for filtering input from any data source
 *
 * Forked from the php input filter library by: Daniel Morris <[e-mail]>
 * Original Contributors: Gianpaolo Racca, Ghislain Picard, Marco Wandschneider, Chris Tobin and Andrew Eddie.
 *
 * @author		Louis Landry <[e-mail]>
 * @package 	Joomla.Framework
 * @subpackage		Filter
 * @since		1.5
 */
class JFilterInput extends JObject
{
	var $tagsArray; // default = empty array
	var $attrArray; // default = empty array

	var $tagsMethod; // default = 0
	var $attrMethod; // default = 0

	var $xssAuto; // default = 1
	var $tagBlacklist = array ('applet', 'body', 'bgsound', 'base', 'basefont', 'embed', 'frame', 'frameset', 'head', 'html', 'id', 'iframe', 'ilayer', 'layer', 'link', 'meta', 'name', 'object', 'script', 'style', 'title', 'xml');
	var $attrBlacklist = array ('action', 'background', 'codebase', 'dynsrc', 'lowsrc'); // also will strip ALL event handlers

	/**
	 * Constructor for inputFilter class. Only first parameter is required.
	 *
	 * @access	protected
	 * @param	array	$tagsArray	list of user-defined tags
	 * @param	array	$attrArray	list of user-defined attributes
	 * @param	int		$tagsMethod	WhiteList method = 0, BlackList method = 1
	 * @param	int		$attrMethod	WhiteList method = 0, BlackList method = 1
	 * @param	int		$xssAuto	Only auto clean essentials = 0, Allow clean blacklisted tags/attr = 1
	 * @since	1.5
	 */
	function __construct($tagsArray = array(), $attrArray = array(), $tagsMethod = 0, $attrMethod = 0, $xssAuto = 1)
	{
		// Make sure user defined arrays are in lowercase
		$tagsArray = array_map('strtolower', (array) $tagsArray);
		$attrArray = array_map('strtolower', (array) $attrArray);

		// Assign member variables
		$this->tagsArray	= $tagsArray;
		$this->attrArray	= $attrArray;
		$this->tagsMethod	= $tagsMethod;
		$this->attrMethod	= $attrMethod;
		$this->xssAuto		= $xssAuto;
	}

	/**
	 * Returns a reference to an input filter object, only creating it if it doesn't already exist.
	 *
	 * This method must be invoked as:
	 * 		<pre>  $filter = & JFilterInput::getInstance();</pre>
	 *
	 * @static
	 * @param	array	$tagsArray	list of user-defined tags
	 * @param	array	$attrArray	list of user-defined attributes
	 * @param	int		$tagsMethod	WhiteList method = 0, BlackList method = 1
	 * @param	int		$attrMethod	WhiteList method = 0, BlackList method = 1
	 * @param	int		$xssAuto	Only auto clean essentials = 0, Allow clean blacklisted tags/attr = 1
	 * @return	object	The JFilterInput object.
	 * @since	1.5
	 */
	function & getInstance($tagsArray = array(), $attrArray = array(), $tagsMethod = 0, $attrMethod = 0, $xssAuto = 1)
	{
		static $instances;

		$sig = md5(serialize(array($tagsArray,$attrArray,$tagsMethod,$attrMethod,$xssAuto)));

		if (!isset ($instances)) {
			$instances = array();
		}

		if (empty ($instances[$sig])) {
			$instances[$sig] = new JFilterInput($tagsArray, $attrArray, $tagsMethod, $attrMethod, $xssAuto);
		}

		return $instances[$sig];
	}

	/**
	 * Method to be called by another php script. Processes for XSS and
	 * specified bad code.
	 *
	 * @access	public
	 * @param	mixed	$source	Input string/array-of-string to be 'cleaned'
	 * @param	string	$type	Return type for the variable (INT, FLOAT, BOOLEAN, WORD, ALNUM, CMD, BASE64, STRING, ARRAY, PATH, NONE)
	 * @return	mixed	'Cleaned' version of input parameter
	 * @since	1.5
	 */
	function clean($source, $type='string')
	{
		// Handle the type constraint
		switch (strtoupper($type))
		{
			case 'INT' :
			case 'INTEGER' :
				// Only use the first integer value
				preg_match('/-?[0-9]+/', (string) $source, $matches);
				$result = @ (int) $matches[0];
				break;

			case 'FLOAT' :
			case 'DOUBLE' :
				// Only use the first floating point value
				preg_match('/-?[0-9]+(\.[0-9]+)?/', (string) $source, $matches);
				$result = @ (float) $matches[0];
				break;

			case 'BOOL' :
			case 'BOOLEAN' :
				$result = (bool) $source;
				break;

			case 'WORD' :
				$result = (string) preg_replace( '/[^A-Z_]/i', '', $source );
				break;

			case 'ALNUM' :
				$result = (string) preg_replace( '/[^A-Z0-9]/i', '', $source );
				break;

			case 'CMD' :
				$result = (string) preg_replace( '/[^A-Z0-9_\.-]/i', '', $source );
				$result = ltrim($result, '.');
				break;

			case 'BASE64' :
				$result = (string) preg_replace( '/[^A-Z0-9\/+=]/i', '', $source );
				break;

			case 'STRING' :
				$result = (string) $this->_remove($this->_decode((string) $source));
				break;

			case 'ARRAY' :
				$result = (array) $source;
				break;

			case 'PATH' :
				$pattern = '/^[A-Za-z0-9_-]+[A-Za-z0-9_\.-]*([\\\\\/][A-Za-z0-9_-]+[A-Za-z0-9_\.-]*)*$/';
				preg_match($pattern, (string) $source, $matches);
				$result = @ (string) $matches[0];
				break;

			case 'USERNAME' :
				$result = (string) preg_replace( '/[\x00-\x1F\x7F<>"\'%&]/', '', $source );
				break;

			default :
				// Are we dealing with an array?
				if (is_array($source)) {
					foreach ($source as $key => $value)
					{
						// filter element for XSS and other 'bad' code etc.
						if (is_string($value)) {
							$source[$key] = $this->_remove($this->_decode($value));
						}
					}
					$result = $source;
				} else {
					// Or a string?
					if (is_string($source) && !empty ($source)) {
						// filter source for XSS and other 'bad' code etc.
						$result = $this->_remove($this->_decode($source));
					} else {
						// Not an array or string.. return the passed parameter
						$result = $source;
					}
				}
				break;
		}
		return $result;
	}

	/**
	 * Function to determine if contents of an attribute is safe
	 *
	 * @static
	 * @param	array	$attrSubSet	A 2 element array for attributes name,value
	 * @return	boolean True if bad code is detected
	 * @since	1.5
	 */
	function checkAttribute($attrSubSet)
	{
		$attrSubSet[0] = strtolower($attrSubSet[0]);
		$attrSubSet[1] = strtolower($attrSubSet[1]);
		return (((strpos($attrSubSet[1], 'expression') !== false) && ($attrSubSet[0]) == 'style') || (strpos($attrSubSet[1], 'javascript:') !== false) || (strpos($attrSubSet[1], 'behaviour:') !== false) || (strpos($attrSubSet[1], 'vbscript:') !== false) || (strpos($attrSubSet[1], 'mocha:') !== false) || (strpos($attrSubSet[1], 'livescript:') !== false));
	}

	/**
	 * Internal method to iteratively remove all unwanted tags and attributes
	 *
	 * @access	protected
	 * @param	string	$source	Input string to be 'cleaned'
	 * @return	string	'Cleaned' version of input parameter
	 * @since	1.5
	 */
	function _remove($source)
	{
		$loopCounter = 0;

		// Iteration provides nested tag protection
		while ($source != $this->_cleanTags($source))
		{
			$source = $this->_cleanTags($source);
			$loopCounter ++;
		}
		return $source;
	}

	/**
	 * Internal method to strip a string of certain tags
	 *
	 * @access	protected
	 * @param	string	$source	Input string to be 'cleaned'
	 * @return	string	'Cleaned' version of input parameter
	 * @since	1.5
	 */
	function _cleanTags($source)
	{
		/*
		 * In the beginning we don't really have a tag, so everything is
		 * postTag
		 */
		$preTag		= null;
		$postTag	= $source;
		$currentSpace = false;
		$attr = '';	 // moffats: setting to null due to issues in migration system - undefined variable errors