File Source for input.php

<?php
/**
* @package Joomla.Platform
* @subpackage Filter
*
* @copyright Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
* @license GNU General Public License version 2 or later; see LICENSE
*/
defined('JPATH_PLATFORM') or die;
/**
* JFilterInput is a class for filtering input from any data source
*
* Forked from the php input filter library by: Daniel Morris <dan@rootcube.com>
* Original Contributors: Gianpaolo Racca, Ghislain Picard, Marco Wandschneider, Chris Tobin and Andrew Eddie.
*
* @package Joomla.Platform
* @subpackage Filter
* @since 11.1
*/
class JFilterInput
{
/**
* A container for JFilterInput instances.
*
* @var array
* @since 11.3
*/
protected static $instances = array();
/**
* The array of permitted tags (white list).
*
* @var array
* @since 11.1
*/
public $tagsArray;
/**
* The array of permitted tag attributes (white list).
*
* @var array
* @since 11.1
*/
public $attrArray;
/**
* The method for sanitising tags: WhiteList method = 0 (default), BlackList method = 1
*
* @var integer
* @since 11.1
*/
public $tagsMethod;
/**
* The method for sanitising attributes: WhiteList method = 0 (default), BlackList method = 1
*
* @var integer
* @since 11.1
*/
public $attrMethod;
/**
* A flag for XSS checks. Only auto clean essentials = 0, Allow clean blacklisted tags/attr = 1
*
* @var integer
* @since 11.1
*/
public $xssAuto;
/**
* The list of the default blacklisted tags.
*
* @var array
* @since 11.1
*/
public $tagBlacklist = array(
'applet',
'body',
'bgsound',
'base',
'basefont',
'embed',
'frame',
'frameset',
'head',
'html',
'id',
'iframe',
'ilayer',
'layer',
'link',
'meta',
'name',
'object',
'script',
'style',
'title',
'xml'
);
/**
* The list of the default blacklisted tag attributes. All event handlers implicit.
*
* @var array
* @since 11.1
*/
public $attrBlacklist = array(
'action',
'background',
'codebase',
'dynsrc',
'lowsrc'
);
/**
* Constructor for inputFilter class. Only first parameter is required.
*
* @param array $tagsArray List of user-defined tags
* @param array $attrArray List of user-defined attributes
* @param integer $tagsMethod WhiteList method = 0, BlackList method = 1
* @param integer $attrMethod WhiteList method = 0, BlackList method = 1
* @param integer $xssAuto Only auto clean essentials = 0, Allow clean blacklisted tags/attr = 1
*
* @since 11.1
*/
public function __construct($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 an input filter object, only creating it if it doesn't already exist.
*
* @param array $tagsArray List of user-defined tags
* @param array $attrArray List of user-defined attributes
* @param integer $tagsMethod WhiteList method = 0, BlackList method = 1
* @param integer $attrMethod WhiteList method = 0, BlackList method = 1
* @param integer $xssAuto Only auto clean essentials = 0, Allow clean blacklisted tags/attr = 1
*
* @return JFilterInput The JFilterInput object.
*
* @since 11.1
*/
public static function &getInstance($tagsArray = array(), $attrArray = array(), $tagsMethod = 0, $attrMethod = 0, $xssAuto = 1)
{
$sig = md5(serialize(array($tagsArray, $attrArray, $tagsMethod, $attrMethod, $xssAuto)));
if (empty(self::$instances[$sig]))
{
self::$instances[$sig] = new JFilterInput($tagsArray, $attrArray, $tagsMethod, $attrMethod, $xssAuto);
}
return self::$instances[$sig];
}
/**
* Method to be called by another php script. Processes for XSS and
* specified bad code.
*
* @param mixed $source Input string/array-of-string to be 'cleaned'
* @param string $type The return type for the variable:
* INT: An integer,
* UINT: An unsigned integer,
* FLOAT: A floating point number,
* BOOLEAN: A boolean value,
* WORD: A string containing A-Z or underscores only (not case sensitive),
* ALNUM: A string containing A-Z or 0-9 only (not case sensitive),
* CMD: A string containing A-Z, 0-9, underscores, periods or hyphens (not case sensitive),
* BASE64: A string containing A-Z, 0-9, forward slashes, plus or equals (not case sensitive),
* STRING: A fully decoded and sanitised string (default),
* HTML: A sanitised string,
* ARRAY: An array,
* PATH: A sanitised file path,
* USERNAME: Do not use (use an application specific filter),
* RAW: The raw string is returned with no filtering,
* unknown: An unknown filter will act like STRING. If the input is an array it will return an
* array of fully decoded and sanitised strings.
*
* @return mixed 'Cleaned' version of input parameter
*
* @since 11.1
*/
public function clean($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 'UINT':
// Only use the first integer value
preg_match('/-?[0-9]+/', (string) $source, $matches);
$result = @ abs((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 'HTML':
$result = (string) $this->_remove((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;
case 'RAW':
$result = $source;
break;
default:
// Are we dealing with an array?
if (is_array($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 are safe
*
* @param array $attrSubSet A 2 element array for attribute's name, value
*
* @return boolean True if bad code is detected
*
* @since 11.1
*/
public static function checkAttribute($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
*
* @param string $source Input string to be 'cleaned'
*
* @return string 'Cleaned' version of input parameter
*
* @since 11.1
*/
protected function _remove($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
*
* @param string $source Input string to be 'cleaned'
*
* @return string 'Cleaned' version of input parameter
*
* @since 11.1
*/
protected function _cleanTags($source)
{
// First, pre-process this for illegal characters inside attribute values
$source = $this->_escapeAttributeValues($source);
// In the beginning we don't really have a tag, so everything is postTag
$preTag = null;
$postTag = $source;
$currentSpace = false;
// Setting to null to deal with undefined variables
$attr = '';
// Is there a tag? If so it will certainly start with a '<'.
$tagOpen_start = strpos($source, '<');
while ($tagOpen_start !== false)
{
// Get some information about the tag we are processing
$preTag .= substr($postTag, 0, $tagOpen_start);
$postTag = substr($postTag, $tagOpen_start);
$fromTagOpen = substr($postTag, 1);
$tagOpen_end = strpos($fromTagOpen, '>');
// Check for mal-formed tag where we have a second '<' before the first '>'
$nextOpenTag = (strlen($postTag) > $tagOpen_start) ? strpos($postTag, '<', $tagOpen_start + 1) : false;
if (($nextOpenTag !== false) && ($nextOpenTag < $tagOpen_end))
{
// At this point we have a mal-formed tag -- remove the offending open
$postTag = substr($postTag, 0, $tagOpen_start) . substr($postTag, $tagOpen_start + 1);
$tagOpen_start = strpos($postTag, '<');
continue;
}
// Let's catch any non-terminated tags and skip over them
if ($tagOpen_end === false)
{
$postTag = substr($postTag, $tagOpen_start + 1);
$tagOpen_start = strpos($postTag, '<');
continue;
}
// Do we have a nested tag?
$tagOpen_nested = strpos($fromTagOpen, '<');
if (($tagOpen_nested !== false) && ($tagOpen_nested < $tagOpen_end))
{
$preTag .= substr($postTag, 0, ($tagOpen_nested + 1));
$postTag = substr($postTag, ($tagOpen_nested + 1));
$tagOpen_start = strpos($postTag, '<');
continue;
}
// Let's get some information about our tag and setup attribute pairs
$tagOpen_nested = (strpos($fromTagOpen, '<') + $tagOpen_start + 1);
$currentTag = substr($fromTagOpen, 0, $tagOpen_end);
$tagLength = strlen($currentTag);
$tagLeft = $currentTag;
$attrSet = array();
$currentSpace = strpos($tagLeft, ' ');
// Are we an open tag or a close tag?
if (substr($currentTag, 0, 1) == '/')
{
// Close Tag
$isCloseTag = true;
list ($tagName) = explode(' ', $currentTag);
$tagName = substr($tagName, 1);
}
else
{
// Open Tag
$isCloseTag = false;
list ($tagName) = explode(' ', $currentTag);
}
/*
* Exclude all "non-regular" tagnames
* OR no tagname
* OR remove if xssauto is on and tag is blacklisted
*/
if ((!preg_match("/^[a-z][a-z0-9]*$/i", $tagName)) || (!$tagName) || ((in_array(strtolower($tagName), $this->tagBlacklist)) && ($this->xssAuto)))
{
$postTag = substr($postTag, ($tagLength + 2));
$tagOpen_start = strpos($postTag, '<');
// Strip tag
continue;
}
/*
* Time to grab any attributes from the tag... need this section in
* case attributes have spaces in the values.
*/
while ($currentSpace !== false)
{
$attr = '';
$fromSpace = substr($tagLeft, ($currentSpace + 1));
$nextEqual = strpos($fromSpace, '=');
$nextSpace = strpos($fromSpace, ' ');
$openQuotes = strpos($fromSpace, '"');
$closeQuotes = strpos(substr($fromSpace, ($openQuotes + 1)), '"') + $openQuotes + 1;
$startAtt = '';
$startAttPosition = 0;
// Find position of equal and open quotes ignoring
if (preg_match('#\s*=\s*\"#', $fromSpace, $matches, PREG_OFFSET_CAPTURE))
{
$startAtt = $matches[0][0];
$startAttPosition = $matches[0][1];
$closeQuotes = strpos(substr($fromSpace, ($startAttPosition + strlen($startAtt))), '"') + $startAttPosition + strlen($startAtt);
$nextEqual = $startAttPosition + strpos($startAtt, '=');
$openQuotes = $startAttPosition + strpos($startAtt, '"');
$nextSpace = strpos(substr($fromSpace, $closeQuotes), ' ') + $closeQuotes;
}
// Do we have an attribute to process? [check for equal sign]
if ($fromSpace != '/' && (($nextEqual && $nextSpace && $nextSpace < $nextEqual) || !$nextEqual))
{
if (!$nextEqual)
{
$attribEnd = strpos($fromSpace, '/') - 1;
}
else
{
$attribEnd = $nextSpace - 1;
}
// If there is an ending, use this, if not, do not worry.
if ($attribEnd > 0)
{
$fromSpace = substr($fromSpace, $attribEnd + 1);
}
}
if (strpos($fromSpace, '=') !== false)
{
// If the attribute value is wrapped in quotes we need to grab the substring from
// the closing quote, otherwise grab until the next space.
if (($openQuotes !== false) && (strpos(substr($fromSpace, ($openQuotes + 1)), '"') !== false))
{
$attr = substr($fromSpace, 0, ($closeQuotes + 1));
}
else
{
$attr = substr($fromSpace, 0, $nextSpace);
}
}
// No more equal signs so add any extra text in the tag into the attribute array [eg. checked]
else
{
if ($fromSpace != '/')
{
$attr = substr($fromSpace, 0, $nextSpace);
}
}
// Last Attribute Pair
if (!$attr && $fromSpace != '/')
{
$attr = $fromSpace;
}
// Add attribute pair to the attribute array
$attrSet[] = $attr;
// Move search point and continue iteration
$tagLeft = substr($fromSpace, strlen($attr));
$currentSpace = strpos($tagLeft, ' ');
}
// Is our tag in the user input array?
$tagFound = in_array(strtolower($tagName), $this->tagsArray);
// If the tag is allowed let's append it to the output string.
if ((!$tagFound && $this->tagsMethod) || ($tagFound && !$this->tagsMethod))
{
// Reconstruct tag with allowed attributes
if (!$isCloseTag)
{
// Open or single tag
$attrSet = $this->_cleanAttributes($attrSet);
$preTag .= '<' . $tagName;
for ($i = 0, $count = count($attrSet); $i < $count; $i++)
{
$preTag .= ' ' . $attrSet[$i];
}
// Reformat single tags to XHTML
if (strpos($fromTagOpen, '</' . $tagName))
{
$preTag .= '>';
}
else
{
$preTag .= ' />';
}
}
// Closing tag
else
{
$preTag .= '</' . $tagName . '>';
}
}
// Find next tag's start and continue iteration
$postTag = substr($postTag, ($tagLength + 2));
$tagOpen_start = strpos($postTag, '<');
}
// Append any code after the end of tags and return
if ($postTag != '<')
{
$preTag .= $postTag;
}
return $preTag;
}
/**
* Internal method to strip a tag of certain attributes
*
* @param array $attrSet Array of attribute pairs to filter
*
* @return array Filtered array of attribute pairs
*
* @since 11.1
*/
protected function _cleanAttributes($attrSet)
{
$newSet = array();
$count = count($attrSet);
// Iterate through attribute pairs
for ($i = 0; $i < $count; $i++)
{
// Skip blank spaces
if (!$attrSet[$i])
{
continue;
}
// Split into name/value pairs
$attrSubSet = explode('=', trim($attrSet[$i]), 2);
// Take the last attribute in case there is an attribute with no value
$attrSubSet[0] = array_pop(explode(' ', trim($attrSubSet[0])));
// Remove all "non-regular" attribute names
// AND blacklisted attributes
if ((!preg_match('/[a-z]*$/i', $attrSubSet[0]))
|| (($this->xssAuto) && ((in_array(strtolower($attrSubSet[0]), $this->attrBlacklist))
|| (substr($attrSubSet[0], 0, 2) == 'on'))))
{
continue;
}
// XSS attribute value filtering
if (isset($attrSubSet[1]))
{
// Trim leading and trailing spaces
$attrSubSet[1] = trim($attrSubSet[1]);
// Strips unicode, hex, etc
$attrSubSet[1] = str_replace('&#', '', $attrSubSet[1]);
// Strip normal newline within attr value
$attrSubSet[1] = preg_replace('/[\n\r]/', '', $attrSubSet[1]);
// Strip double quotes
$attrSubSet[1] = str_replace('"', '', $attrSubSet[1]);
// Convert single quotes from either side to doubles (Single quotes shouldn't be used to pad attr values)
if ((substr($attrSubSet[1], 0, 1) == "'") && (substr($attrSubSet[1], (strlen($attrSubSet[1]) - 1), 1) == "'"))
{
$attrSubSet[1] = substr($attrSubSet[1], 1, (strlen($attrSubSet[1]) - 2));
}
// Strip slashes
$attrSubSet[1] = stripslashes($attrSubSet[1]);
}
else
{
continue;
}
// Autostrip script tags
if (self::checkAttribute($attrSubSet))
{
continue;
}
// Is our attribute in the user input array?
$attrFound = in_array(strtolower($attrSubSet[0]), $this->attrArray);
// If the tag is allowed lets keep it
if ((!$attrFound && $this->attrMethod) || ($attrFound && !$this->attrMethod))
{
// Does the attribute have a value?
if (empty($attrSubSet[1]) === false)
{
$newSet[] = $attrSubSet[0] . '="' . $attrSubSet[1] . '"';
}
elseif ($attrSubSet[1] === "0")
{
// Special Case
// Is the value 0?
$newSet[] = $attrSubSet[0] . '="0"';
}
else
{
// Leave empty attributes alone
$newSet[] = $attrSubSet[0] . '=""';
}
}
}
return $newSet;
}
/**
* Try to convert to plaintext
*
* @param string $source The source string.
*
* @return string Plaintext string
*
* @since 11.1
*/
protected function _decode($source)
{
static $ttr;
if (!is_array($ttr))
{
// Entity decode
if (version_compare(PHP_VERSION, '5.3.4', '>='))
{
$trans_tbl = get_html_translation_table(HTML_ENTITIES, ENT_COMPAT, 'ISO-8859-1');
}
else
{
$trans_tbl = get_html_translation_table(HTML_ENTITIES, ENT_COMPAT);
}
foreach ($trans_tbl as $k => $v)
{
$ttr[$v] = utf8_encode($k);
}
}
$source = strtr($source, $ttr);
// Convert decimal
$source = preg_replace_callback('/&#(\d+);/m', function($m)
{
return utf8_encode(chr($m[1]));
}, $source
);
// Convert hex
$source = preg_replace_callback('/&#x([a-f0-9]+);/mi', function($m)
{
return utf8_encode(chr('0x' . $m[1]));
}, $source
);
return $source;
}
/**
* Escape < > and " inside attribute values
*
* @param string $source The source string.
*
* @return string Filtered string
*
* @since 11.1
*/
protected function _escapeAttributeValues($source)
{
$alreadyFiltered = '';
$remainder = $source;
$badChars = array('<', '"', '>');
$escapedChars = array('<', '"', '>');
// Process each portion based on presence of =" and "<space>, "/>, or ">
// See if there are any more attributes to process
while (preg_match('#<[^>]*?=\s*?(\"|\')#s', $remainder, $matches, PREG_OFFSET_CAPTURE))
{
// Get the portion before the attribute value
$quotePosition = $matches[0][1];
$nextBefore = $quotePosition + strlen($matches[0][0]);
// Figure out if we have a single or double quote and look for the matching closing quote
// Closing quote should be "/>, ">, "<space>, or " at the end of the string
$quote = substr($matches[0][0], -1);
$pregMatch = ($quote == '"') ? '#(\"\s*/\s*>|\"\s*>|\"\s+|\"$)#' : "#(\'\s*/\s*>|\'\s*>|\'\s+|\'$)#";
// Get the portion after attribute value
if (preg_match($pregMatch, substr($remainder, $nextBefore), $matches, PREG_OFFSET_CAPTURE))
{
// We have a closing quote
$nextAfter = $nextBefore + $matches[0][1];
}
else
{
// No closing quote
$nextAfter = strlen($remainder);
}
// Get the actual attribute value
$attributeValue = substr($remainder, $nextBefore, $nextAfter - $nextBefore);
// Escape bad chars
$attributeValue = str_replace($badChars, $escapedChars, $attributeValue);
$attributeValue = $this->_stripCSSExpressions($attributeValue);
$alreadyFiltered .= substr($remainder, 0, $nextBefore) . $attributeValue . $quote;
$remainder = substr($remainder, $nextAfter + 1);
}
// At this point, we just have to return the $alreadyFiltered and the $remainder
return $alreadyFiltered . $remainder;
}
/**
* Remove CSS Expressions in the form of <property>:expression(...)
*
* @param string $source The source string.
*
* @return string Filtered string
*
* @since 11.1
*/
protected function _stripCSSExpressions($source)
{
// Strip any comments out (in the form of /*...*/)
$test = preg_replace('#\/\*.*\*\/#U', '', $source);
// Test for :expression
if (!stripos($test, ':expression'))
{
// Not found, so we are done
$return = $source;
}
else
{
// At this point, we have stripped out the comments and have found :expression
// Test stripped string for :expression followed by a '('
if (preg_match_all('#:expression\s*\(#', $test, $matches))
{
// If found, remove :expression
$test = str_ireplace(':expression', '', $test);
$return = $test;
}
}
return $return;
}
}

Documentation generated on Tue, 19 Nov 2013 15:05:35 +0100 by phpDocumentor 1.4.3

Source for file input.php