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<?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 = offforeach (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 $_GET to an empty arrayif ($this->allow_get_array == FALSE){$_GET = array();}else{$_GET = $this->_clean_input_data($_GET);}// Clean $_POST Data$_POST = $this->_clean_input_data($_POST);// Clean $_COOKIE Data// Also get rid of specially treated cookies that might be set by a server// or silly application, that are of no use to a CI application anyway// but that when present will trip our 'Disallowed Key Characters' alarm// http://www.ietf.org/rfc/rfc2109.txt// note that the key names below are single quoted strings, and are not PHP variablesunset($_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 $new_array;}// We strip slashes if magic quotes is on to keep things consistentif (get_magic_quotes_gpc()){$str = stripslashes($str);}// Should we filter the input data?if ($this->use_xss_clean === TRUE){$str = $this->xss_clean($str);}// Standardize newlinesif (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('.', $ip);// Always 4 segments neededif (count($ip_segments) != 4){return FALSE;}// IP can not start with 0if ($ip_segments[0][0] == '0'){return FALSE;}// Check each segmentforeach ($ip_segments as $segment){// IP segments must be digits and can not be// longer than 3 digits or greater then 255if ($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();elsemt_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($charset));}// --------------------------------------------------------------------/*** HTML Entities Decode** This function is a replacement for html_entity_decode()** In some versions of PHP the native function does not work* when UTF-8 is the specified character set, so this gives us* a work-around. More info here:* http://bugs.php.net/bug.php?id=25670** @access private* @param string* @param string* @return string*//* -------------------------------------------------/* Replacement for html_entity_decode()/* -------------------------------------------------*//*NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is thecharacter set, and the PHP developers said they were not back porting thefix to versions other than PHP 5.x.*/function _html_entity_decode($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)', $str);// Literal Entities - Slightly slow so we do another checkif (stristr($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 */