SkidSec WebShell

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PHP Version : 7.4.33

<?php /** * CodeIgniter * * An open source application development framework for PHP * * This content is released under the MIT License (MIT) * * Copyright (c) 2014 - 2018, 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 - 2018, 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).cookie' => '[removed]', 'document.write' => '[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$?|$?window$?(\.document)?)\.(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 config foreach (array('csrf_expire', 'csrf_token_name', 'csrf_cookie_name') as $key) { if (NULL !== ($val = config_item($key))) { $this->{'_'.$key} = $val; } } // Append application specific cookie prefix if ($cookie_prefix = config_item('cookie_prefix')) { $this->_csrf_cookie_name = $cookie_prefix.$this->_csrf_cookie_name; } // Set the CSRF hash $this->_csrf_set_hash(); } $this->charset = strtoupper(config_item('charset')); log_message('info', 'Security Class Initialized'); } // -------------------------------------------------------------------- /** * CSRF Verify * * @return CI_Security */ public function csrf_verify() { // If it's not a POST request we will set the CSRF cookie if (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST') { return $this->csrf_set_cookie(); } // Check if URI has been whitelisted from CSRF checks if ($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 array unset($_POST[$this->_csrf_token_name]); // Regenerate on every submission? if (config_item('csrf_regenerate')) { // Nothing should last forever unset($_COOKIE[$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 ); // Same thing, but for "tag functions" (e.g. eval`some code`) // See https://github.com/bcit-ci/CodeIgniter/issues/5420 $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 TypeError return 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, $charset)); // If we're not on PHP 5.4+, add the possibly dangerous HTML 5 // entities to the array manually if ($flag === ENT_COMPAT) { $_entities[':'] = '&colon;'; $_entities['('] = '('; $_entities[')'] = ')'; $_entities["\n"] = '&NewLine;'; $_entities["\t"] = '&Tab;'; } } do { $str_compare = $str; // Decode standard entities, avoiding false positives if (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 $evil_attributes = array( 'on\w+', 'style', 'xmlns', 'formaction', 'form', 'xlink:href', 'FSCommand', 'seekSegmentTime' ); // First, escape unclosed tags if (empty($matches['closeTag'])) { return '<'.$matches[1]; } // Is the element that we caught naughty? If so, escape it elseif (in_array(strtolower($matches['tagName']), $naughty_tags, TRUE)) { return '<'.$matches[1].'>'; } // For other tags, see if their attributes are "evil" and strip those elseif (isset($matches['attributes'])) { // We'll store the already filtered 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 attribute do { // 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'], $attribute, PREG_OFFSET_CAPTURE)) { // No (valid) attribute found? Discard everything else inside the tag break; } if ( // Is it indeed an "evil" attribute? preg_match($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;|`|&\#96;)|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;|`|&\#96;)|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 vars return 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 fail if (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; } }