Propset eol-style to CRLF
simplified paragraph tag cleanup regex
diff --git a/system/libraries/Input.php b/system/libraries/Input.php
index f26df75..fe76559 100644
--- a/system/libraries/Input.php
+++ b/system/libraries/Input.php
@@ -1,1059 +1,1059 @@
-<?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]',
- '<!--' => '<!--',
- '-->' => '-->',
- '<![CDATA[' => '<![CDATA['
- );
- /* never allowed, regex replacement */
- var $never_allowed_regex = array(
- "javascript\s*:" => '[removed]',
- "expression\s*\(" => '[removed]', // CSS and IE
- "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 $this->ip_address;
- }
-
- if ($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);
- $this->ip_address = end($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;", $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('<?php', '<?PHP'), $str);
- }
- else
- {
- $str = str_replace(array('<?php', '<?PHP', '<?', '?'.'>'), array('<?php', '<?PHP', '<?', '?>'), $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('>', '<'), $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('>', '<'), $match[0]);
- }
-
- // --------------------------------------------------------------------
-
- /**
- * HTML Entity Decode Callback
- *
- * Used as a callback for XSS Clean
- *
- * @access public
- * @param array
- * @return string
- */
- function _html_entity_decode_callback($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)
- {
- $out .= "{$match}";
- }
- }
-
- return $out;
- }
-
- // --------------------------------------------------------------------
-
-}
-// END Input class
-
-/* End of file Input.php */
+<?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]',
+ '<!--' => '<!--',
+ '-->' => '-->',
+ '<![CDATA[' => '<![CDATA['
+ );
+ /* never allowed, regex replacement */
+ var $never_allowed_regex = array(
+ "javascript\s*:" => '[removed]',
+ "expression\s*\(" => '[removed]', // CSS and IE
+ "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 $this->ip_address;
+ }
+
+ if ($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);
+ $this->ip_address = end($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;", $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('<?php', '<?PHP'), $str);
+ }
+ else
+ {
+ $str = str_replace(array('<?php', '<?PHP', '<?', '?'.'>'), array('<?php', '<?PHP', '<?', '?>'), $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('>', '<'), $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('>', '<'), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entity Decode Callback
+ *
+ * Used as a callback for XSS Clean
+ *
+ * @access public
+ * @param array
+ * @return string
+ */
+ function _html_entity_decode_callback($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)
+ {
+ $out .= "{$match}";
+ }
+ }
+
+ return $out;
+ }
+
+ // --------------------------------------------------------------------
+
+}
+// END Input class
+
+/* End of file Input.php */
/* Location: ./system/libraries/Input.php */
\ No newline at end of file