Revision 2242 | Zur aktuellen Revision | Blame | Vergleich mit vorheriger | Letzte Änderung | Log anzeigen | RSS feed
<?php/*** CodeIgniter** An open source application development framework for PHP** This content is released under the MIT License (MIT)** Copyright (c) 2014 - 2017, British Columbia Institute of Technology** Permission is hereby granted, free of charge, to any person obtaining a copy* of this software and associated documentation files (the "Software"), to deal* in the Software without restriction, including without limitation the rights* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell* copies of the Software, and to permit persons to whom the Software is* furnished to do so, subject to the following conditions:** The above copyright notice and this permission notice shall be included in* all copies or substantial portions of the Software.** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN* THE SOFTWARE.** @package CodeIgniter* @author EllisLab Dev Team* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)* @copyright Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)* @license http://opensource.org/licenses/MIT MIT License* @link https://codeigniter.com* @since Version 1.0.0* @filesource*/defined('BASEPATH') OR exit('No direct script access allowed');/*** Security Class** @package CodeIgniter* @subpackage Libraries* @category Security* @author EllisLab Dev Team* @link https://codeigniter.com/user_guide/libraries/security.html*/class CI_Security {/*** List of sanitize filename strings** @var array*/public $filename_bad_chars = array('../', '<!--', '-->', '<', '>',"'", '"', '&', '$', '#','{', '}', '[', ']', '=',';', '?', '%20', '%22','%3c', // <'%253c', // <'%3e', // >'%0e', // >'%28', // ('%29', // )'%2528', // ('%26', // &'%24', // $'%3f', // ?'%3b', // ;'%3d' // =);/*** Character set** Will be overridden by the constructor.** @var string*/public $charset = 'UTF-8';/*** XSS Hash** Random Hash for protecting URLs.** @var string*/protected $_xss_hash;/*** CSRF Hash** Random hash for Cross Site Request Forgery protection cookie** @var string*/protected $_csrf_hash;/*** CSRF Expire time** Expiration time for Cross Site Request Forgery protection cookie.* Defaults to two hours (in seconds).** @var int*/protected $_csrf_expire = 7200;/*** CSRF Token name** Token name for Cross Site Request Forgery protection cookie.** @var string*/protected $_csrf_token_name = 'ci_csrf_token';/*** CSRF Cookie name** Cookie name for Cross Site Request Forgery protection cookie.** @var string*/protected $_csrf_cookie_name = 'ci_csrf_token';/*** List of never allowed strings** @var array*/protected $_never_allowed_str = array('document.cookie' => '[removed]','document.write' => '[removed]','.parentNode' => '[removed]','.innerHTML' => '[removed]','-moz-binding' => '[removed]','<!--' => '<!--','-->' => '-->','<![CDATA[' => '<![CDATA[','<comment>' => '<comment>','<%' => '<%');/*** List of never allowed regex replacements** @var array*/protected $_never_allowed_regex = array('javascript\s*:','(document|(document\.)?window)\.(location|on\w*)','expression\s*(\(|&\#40;)', // CSS and IE'vbscript\s*:', // IE, surprise!'wscript\s*:', // IE'jscript\s*:', // IE'vbs\s*:', // IE'Redirect\s+30\d',"([\"'])?data\s*:[^\\1]*?base64[^\\1]*?,[^\\1]*?\\1?");/*** Class constructor** @return void*/public function __construct(){// Is CSRF protection enabled?if (config_item('csrf_protection')){// CSRF configforeach (array('csrf_expire', 'csrf_token_name', 'csrf_cookie_name') as $key){if (NULL !== ($val = config_item($key))){$this->{'_'.$key} = $val;}}// Append application specific cookie prefixif ($cookie_prefix = config_item('cookie_prefix')){$this->_csrf_cookie_name = $cookie_prefix.$this->_csrf_cookie_name;}// Set the CSRF hash$this->_csrf_set_hash();}$this->charset = strtoupper(config_item('charset'));log_message('info', 'Security Class Initialized');}// --------------------------------------------------------------------/*** CSRF Verify** @return CI_Security*/public function csrf_verify(){// If it's not a POST request we will set the CSRF cookieif (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST'){return $this->csrf_set_cookie();}// Check if URI has been whitelisted from CSRF checksif ($exclude_uris = config_item('csrf_exclude_uris')){$uri = load_class('URI', 'core');foreach ($exclude_uris as $excluded){if (preg_match('#^'.$excluded.'$#i'.(UTF8_ENABLED ? 'u' : ''), $uri->uri_string())){return $this;}}}// Check CSRF token validity, but don't error on mismatch just yet - we'll want to regenerate$valid = isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name])&& hash_equals($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]);// We kill this since we're done and we don't want to pollute the _POST arrayunset($_POST[$this->_csrf_token_name]);// Regenerate on every submission?if (config_item('csrf_regenerate')){// Nothing should last foreverunset($_COOKIE[$this->_csrf_cookie_name]);$this->_csrf_hash = NULL;}$this->_csrf_set_hash();$this->csrf_set_cookie();if ($valid !== TRUE){$this->csrf_show_error();}log_message('info', 'CSRF token verified');return $this;}// --------------------------------------------------------------------/*** CSRF Set Cookie** @codeCoverageIgnore* @return CI_Security*/public function csrf_set_cookie(){$expire = time() + $this->_csrf_expire;$secure_cookie = (bool) config_item('cookie_secure');if ($secure_cookie && ! is_https()){return FALSE;}setcookie($this->_csrf_cookie_name,$this->_csrf_hash,$expire,config_item('cookie_path'),config_item('cookie_domain'),$secure_cookie,config_item('cookie_httponly'));log_message('info', 'CSRF cookie sent');return $this;}// --------------------------------------------------------------------/*** Show CSRF Error** @return void*/public function csrf_show_error(){show_error('The action you have requested is not allowed.', 403);}// --------------------------------------------------------------------/*** Get CSRF Hash** @see CI_Security::$_csrf_hash* @return string CSRF hash*/public function get_csrf_hash(){return $this->_csrf_hash;}// --------------------------------------------------------------------/*** Get CSRF Token Name** @see CI_Security::$_csrf_token_name* @return string CSRF token name*/public function get_csrf_token_name(){return $this->_csrf_token_name;}// --------------------------------------------------------------------/*** XSS Clean** Sanitizes data so that Cross Site Scripting Hacks can be* prevented. This method 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: Should only be used to deal with data upon submission.* It's not something that should be used for general* runtime processing.** @link http://channel.bitflux.ch/wiki/XSS_Prevention* Based in part on some code and ideas from Bitflux.** @link http://ha.ckers.org/xss.html* 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.** @param string|string[] $str Input data* @param bool $is_image Whether the input is an image* @return string*/public function xss_clean($str, $is_image = FALSE){// Is the string an array?if (is_array($str)){foreach ($str as $key => &$value){$str[$key] = $this->xss_clean($value);}return $str;}// Remove Invisible Characters$str = remove_invisible_characters($str);/** URL Decode** Just in case stuff like this is submitted:** <a href="http://%77%77%77%2E%67%6F%6F%67%6C%65%2E%63%6F%6D">Google</a>** Note: Use rawurldecode() so it does not remove plus signs*/if (stripos($str, '%') !== false){do{$oldstr = $str;$str = rawurldecode($str);$str = preg_replace_callback('#%(?:\s*[0-9a-f]){2,}#i', array($this, '_urldecodespaces'), $str);}while ($oldstr !== $str);unset($oldstr);}/** 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.*/$str = preg_replace_callback("/[^a-z0-9>]+[a-z0-9]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);$str = preg_replace_callback('/<\w+.*/si', array($this, '_decode_entity'), $str);// Remove Invisible Characters Again!$str = remove_invisible_characters($str);/** Convert all tabs to spaces** This prevents strings like this: ja vascript* NOTE: we deal with spaces between characters later.* NOTE: preg_replace was found to be amazingly slow here on* large blocks of data, so we use str_replace.*/$str = str_replace("\t", ' ', $str);// Capture converted string for later comparison$converted_string = $str;// Remove Strings that are never allowed$str = $this->_do_never_allowed($str);/** Makes PHP tags safe** Note: XML tags are inadvertently replaced too:** <?xml** But it doesn't seem to pose a problem.*/if ($is_image === TRUE){// Images have a tendency to have the PHP short opening and// closing tags every so often so we skip those and only// do the long opening tags.$str = preg_replace('/<\?(php)/i', '<?\\1', $str);}else{$str = str_replace(array('<?', '?'.'>'), array('<?', '?>'), $str);}/** Compact any exploded words** This corrects words like: j a v a s c r i p t* These words are compacted back to their correct state.*/$words = array('javascript', 'expression', 'vbscript', 'jscript', 'wscript','vbs', 'script', 'base64', 'applet', 'alert', 'document','write', 'cookie', 'window', 'confirm', 'prompt', 'eval');foreach ($words as $word){$word = implode('\s*', str_split($word)).'\s*';// We only want to do this when it is followed by a non-word character// That way valid stuff like "dealer to" does not become "dealerto"$str = preg_replace_callback('#('.substr($word, 0, -3).')(\W)#is', array($this, '_compact_exploded_words'), $str);}/** Remove disallowed Javascript in links or img tags* We used to do some version comparisons and use of stripos(),* but it is dog slow compared to these simplified non-capturing* preg_match(), especially if the pattern exists in the string** Note: It was reported that not only space characters, but all in* the following pattern can be parsed as separators between a tag name* and its attributes: [\d\s"\'`;,\/\=\(\x00\x0B\x09\x0C]* ... however, remove_invisible_characters() above already strips the* hex-encoded ones, so we'll skip them below.*/do{$original = $str;if (preg_match('/<a/i', $str)){$str = preg_replace_callback('#<a(?:rea)?[^a-z0-9>]+([^>]*?)(?:>|$)#si', array($this, '_js_link_removal'), $str);}if (preg_match('/<img/i', $str)){$str = preg_replace_callback('#<img[^a-z0-9]+([^>]*?)(?:\s?/?>|$)#si', array($this, '_js_img_removal'), $str);}if (preg_match('/script|xss/i', $str)){$str = preg_replace('#</*(?:script|xss).*?>#si', '[removed]', $str);}}while ($original !== $str);unset($original);/** 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>*/$pattern = '#'.'<((?<slash>/*\s*)((?<tagName>[a-z0-9]+)(?=[^a-z0-9]|$)|.+)' // tag start and name, followed by a non-tag character.'[^\s\042\047a-z0-9>/=]*' // a valid attribute character immediately after the tag would count as a separator// optional attributes.'(?<attributes>(?:[\s\042\047/=]*' // non-attribute characters, excluding > (tag close) for obvious reasons.'[^\s\042\047>/=]+' // attribute characters// optional attribute-value.'(?:\s*=' // attribute-value separator.'(?:[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*))' // single, double or non-quoted value.')?' // end optional attribute-value group.')*)' // end optional attributes group.'[^>]*)(?<closeTag>\>)?#isS';// Note: It would be nice to optimize this for speed, BUT// only matching the naughty elements here results in// false positives and in turn - vulnerabilities!do{$old_str = $str;$str = preg_replace_callback($pattern, array($this, '_sanitize_naughty_html'), $str);}while ($old_str !== $str);unset($old_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|prompt|confirm|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si','\\1\\2(\\3)',$str);// Final clean up// This adds a bit of extra precaution in case// something got through the above filters$str = $this->_do_never_allowed($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 ($is_image === TRUE){return ($str === $converted_string);}return $str;}// --------------------------------------------------------------------/*** XSS Hash** Generates the XSS hash if needed and returns it.** @see CI_Security::$_xss_hash* @return string XSS hash*/public function xss_hash(){if ($this->_xss_hash === NULL){$rand = $this->get_random_bytes(16);$this->_xss_hash = ($rand === FALSE)? md5(uniqid(mt_rand(), TRUE)): bin2hex($rand);}return $this->_xss_hash;}// --------------------------------------------------------------------/*** Get random bytes** @param int $length Output length* @return string*/public function get_random_bytes($length){if (empty($length) OR ! ctype_digit((string) $length)){return FALSE;}if (function_exists('random_bytes')){try{// The cast is required to avoid TypeErrorreturn random_bytes((int) $length);}catch (Exception $e){// If random_bytes() can't do the job, we can't either ...// There's no point in using fallbacks.log_message('error', $e->getMessage());return FALSE;}}// Unfortunately, none of the following PRNGs is guaranteed to exist ...if (defined('MCRYPT_DEV_URANDOM') && ($output = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM)) !== FALSE){return $output;}if (is_readable('/dev/urandom') && ($fp = fopen('/dev/urandom', 'rb')) !== FALSE){// Try not to waste entropy ...is_php('5.4') && stream_set_chunk_size($fp, $length);$output = fread($fp, $length);fclose($fp);if ($output !== FALSE){return $output;}}if (function_exists('openssl_random_pseudo_bytes')){return openssl_random_pseudo_bytes($length);}return FALSE;}// --------------------------------------------------------------------/*** HTML Entities Decode** A replacement for html_entity_decode()** 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.** @link http://php.net/html-entity-decode** @param string $str Input* @param string $charset Character set* @return string*/public function entity_decode($str, $charset = NULL){if (strpos($str, '&') === FALSE){return $str;}static $_entities;isset($charset) OR $charset = $this->charset;$flag = is_php('5.4')? ENT_COMPAT | ENT_HTML5: ENT_COMPAT;if ( ! isset($_entities)){$_entities = array_map('strtolower', get_html_translation_table(HTML_ENTITIES, $flag, $charset));// If we're not on PHP 5.4+, add the possibly dangerous HTML 5// entities to the array manuallyif ($flag === ENT_COMPAT){$_entities[':'] = ':';$_entities['('] = '(';$_entities[')'] = ')';$_entities["\n"] = '
';$_entities["\t"] = '	';}}do{$str_compare = $str;// Decode standard entities, avoiding false positivesif (preg_match_all('/&[a-z]{2,}(?![a-z;])/i', $str, $matches)){$replace = array();$matches = array_unique(array_map('strtolower', $matches[0]));foreach ($matches as &$match){if (($char = array_search($match.';', $_entities, TRUE)) !== FALSE){$replace[$match] = $char;}}$str = str_replace(array_keys($replace), array_values($replace), $str);}// Decode numeric & UTF16 two byte entities$str = html_entity_decode(preg_replace('/(&#(?:x0*[0-9a-f]{2,5}(?![0-9a-f;])|(?:0*\d{2,4}(?![0-9;]))))/iS', '$1;', $str),$flag,$charset);if ($flag === ENT_COMPAT){$str = str_replace(array_values($_entities), array_keys($_entities), $str);}}while ($str_compare !== $str);return $str;}// --------------------------------------------------------------------/*** Sanitize Filename** @param string $str Input file name* @param bool $relative_path Whether to preserve paths* @return string*/public function sanitize_filename($str, $relative_path = FALSE){$bad = $this->filename_bad_chars;if ( ! $relative_path){$bad[] = './';$bad[] = '/';}$str = remove_invisible_characters($str, FALSE);do{$old = $str;$str = str_replace($bad, '', $str);}while ($old !== $str);return stripslashes($str);}// ----------------------------------------------------------------/*** Strip Image Tags** @param string $str* @return string*/public function strip_image_tags($str){return preg_replace(array('#<img[\s/]+.*?src\s*=\s*(["\'])([^\\1]+?)\\1.*?\>#i','#<img[\s/]+.*?src\s*=\s*?(([^\s"\'=<>`]+)).*?\>#i'),'\\2',$str);}// ----------------------------------------------------------------/*** URL-decode taking spaces into account** @see https://github.com/bcit-ci/CodeIgniter/issues/4877* @param array $matches* @return string*/protected function _urldecodespaces($matches){$input = $matches[0];$nospaces = preg_replace('#\s+#', '', $input);return ($nospaces === $input)? $input: rawurldecode($nospaces);}// ----------------------------------------------------------------/*** Compact Exploded Words** Callback method for xss_clean() to remove whitespace from* things like 'j a v a s c r i p t'.** @used-by CI_Security::xss_clean()* @param array $matches* @return string*/protected function _compact_exploded_words($matches){return preg_replace('/\s+/s', '', $matches[1]).$matches[2];}// --------------------------------------------------------------------/*** Sanitize Naughty HTML** Callback method for xss_clean() to remove naughty HTML elements.** @used-by CI_Security::xss_clean()* @param array $matches* @return string*/protected function _sanitize_naughty_html($matches){static $naughty_tags = array('alert', 'area', 'prompt', 'confirm', 'applet', 'audio', 'basefont', 'base', 'behavior', 'bgsound','blink', 'body', 'embed', 'expression', 'form', 'frameset', 'frame', 'head', 'html', 'ilayer','iframe', 'input', 'button', 'select', 'isindex', 'layer', 'link', 'meta', 'keygen', 'object','plaintext', 'style', 'script', 'textarea', 'title', 'math', 'video', 'svg', 'xml', 'xss');static $evil_attributes = array('on\w+', 'style', 'xmlns', 'formaction', 'form', 'xlink:href', 'FSCommand', 'seekSegmentTime');// First, escape unclosed tagsif (empty($matches['closeTag'])){return '<'.$matches[1];}// Is the element that we caught naughty? If so, escape itelseif (in_array(strtolower($matches['tagName']), $naughty_tags, TRUE)){return '<'.$matches[1].'>';}// For other tags, see if their attributes are "evil" and strip thoseelseif (isset($matches['attributes'])){// We'll store the already fitlered attributes here$attributes = array();// Attribute-catching pattern$attributes_pattern = '#'.'(?<name>[^\s\042\047>/=]+)' // attribute characters// optional attribute-value.'(?:\s*=(?<value>[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*)))' // attribute-value separator.'#i';// Blacklist pattern for evil attribute names$is_evil_pattern = '#^('.implode('|', $evil_attributes).')$#i';// Each iteration filters a single attributedo{// Strip any non-alpha characters that may precede an attribute.// Browsers often parse these incorrectly and that has been a// of numerous XSS issues we've had.$matches['attributes'] = preg_replace('#^[^a-z]+#i', '', $matches['attributes']);if ( ! preg_match($attributes_pattern, $matches['attributes'], $attribute, PREG_OFFSET_CAPTURE)){// No (valid) attribute found? Discard everything else inside the tagbreak;}if (// Is it indeed an "evil" attribute?preg_match($is_evil_pattern, $attribute['name'][0])// Or does it have an equals sign, but no value and not quoted? Strip that too!OR (trim($attribute['value'][0]) === '')){$attributes[] = 'xss=removed';}else{$attributes[] = $attribute[0][0];}$matches['attributes'] = substr($matches['attributes'], $attribute[0][1] + strlen($attribute[0][0]));}while ($matches['attributes'] !== '');$attributes = empty($attributes)? '': ' '.implode(' ', $attributes);return '<'.$matches['slash'].$matches['tagName'].$attributes.'>';}return $matches[0];}// --------------------------------------------------------------------/*** JS Link Removal** Callback method 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.** @used-by CI_Security::xss_clean()* @param array $match* @return string*/protected function _js_link_removal($match){return str_replace($match[1],preg_replace('#href=.*?(?:(?:alert|prompt|confirm)(?:\(|&\#40;)|javascript:|livescript:|mocha:|charset=|window\.|document\.|\.cookie|<script|<xss|d\s*a\s*t\s*a\s*:)#si','',$this->_filter_attributes($match[1])),$match[0]);}// --------------------------------------------------------------------/*** JS Image Removal** Callback method 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.** @used-by CI_Security::xss_clean()* @param array $match* @return string*/protected function _js_img_removal($match){return str_replace($match[1],preg_replace('#src=.*?(?:(?:alert|prompt|confirm|eval)(?:\(|&\#40;)|javascript:|livescript:|mocha:|charset=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si','',$this->_filter_attributes($match[1])),$match[0]);}// --------------------------------------------------------------------/*** Attribute Conversion** @used-by CI_Security::xss_clean()* @param array $match* @return string*/protected function _convert_attribute($match){return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);}// --------------------------------------------------------------------/*** Filter Attributes** Filters tag attributes for consistency and safety.** @used-by CI_Security::_js_img_removal()* @used-by CI_Security::_js_link_removal()* @param string $str* @return string*/protected function _filter_attributes($str){$out = '';if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches)){foreach ($matches[0] as $match){$out .= preg_replace('#/\*.*?\*/#s', '', $match);}}return $out;}// --------------------------------------------------------------------/*** HTML Entity Decode Callback** @used-by CI_Security::xss_clean()* @param array $match* @return string*/protected function _decode_entity($match){// Protect GET variables in URLs// 901119URL5918AMP18930PROTECT8198$match = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-/]+)|i', $this->xss_hash().'\\1=\\2', $match[0]);// Decode, then un-protect URL GET varsreturn str_replace($this->xss_hash(),'&',$this->entity_decode($match, $this->charset));}// --------------------------------------------------------------------/*** Do Never Allowed** @used-by CI_Security::xss_clean()* @param string* @return string*/protected function _do_never_allowed($str){$str = str_replace(array_keys($this->_never_allowed_str), $this->_never_allowed_str, $str);foreach ($this->_never_allowed_regex as $regex){$str = preg_replace('#'.$regex.'#is', '[removed]', $str);}return $str;}// --------------------------------------------------------------------/*** Set CSRF Hash and Cookie** @return string*/protected function _csrf_set_hash(){if ($this->_csrf_hash === NULL){// If the cookie exists we will use its value.// We don't necessarily want to regenerate it with// each page load since a page could contain embedded// sub-pages causing this feature to failif (isset($_COOKIE[$this->_csrf_cookie_name]) && is_string($_COOKIE[$this->_csrf_cookie_name])&& preg_match('#^[0-9a-f]{32}$#iS', $_COOKIE[$this->_csrf_cookie_name]) === 1){return $this->_csrf_hash = $_COOKIE[$this->_csrf_cookie_name];}$rand = $this->get_random_bytes(16);$this->_csrf_hash = ($rand === FALSE)? md5(uniqid(mt_rand(), TRUE)): bin2hex($rand);}return $this->_csrf_hash;}}