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-rwxr-xr-xsystem/libraries/Security.php737
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diff --git a/system/libraries/Security.php b/system/libraries/Security.php
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-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
-/**
- * CodeIgniter
- *
- * An open source application development framework for PHP 5.1.6 or newer
- *
- * @package CodeIgniter
- * @author ExpressionEngine Dev Team
- * @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
- * @license http://codeigniter.com/user_guide/license.html
- * @link http://codeigniter.com
- * @since Version 1.0
- * @filesource
- */
-
-// ------------------------------------------------------------------------
-
-/**
- * Security Class
- *
- * @package CodeIgniter
- * @subpackage Libraries
- * @category Security
- * @author ExpressionEngine Dev Team
- * @link http://codeigniter.com/user_guide/libraries/sessions.html
- */
-class CI_Security {
-
- public $xss_hash = '';
- public $csrf_hash = '';
- public $csrf_expire = 7200; // Two hours (in seconds)
- public $csrf_token_name = 'ci_csrf_token';
- public $csrf_cookie_name = 'ci_csrf_token';
-
- /* never allowed, string replacement */
- public $never_allowed_str = array(
- 'document.cookie' => '[removed]',
- 'document.write' => '[removed]',
- '.parentNode' => '[removed]',
- '.innerHTML' => '[removed]',
- 'window.location' => '[removed]',
- '-moz-binding' => '[removed]',
- '<!--' => '&lt;!--',
- '-->' => '--&gt;',
- '<![CDATA[' => '&lt;![CDATA['
- );
- /* never allowed, regex replacement */
- public $never_allowed_regex = array(
- "javascript\s*:" => '[removed]',
- "expression\s*(\(|&\#40;)" => '[removed]', // CSS and IE
- "vbscript\s*:" => '[removed]', // IE, surprise!
- "Redirect\s+302" => '[removed]'
- );
-
- public function __construct()
- {
- $this->csrf_token_name = (config_item('csrf_token_name')) ? config_item('csrf_token_name') : 'csrf_token_name';
- $this->csrf_cookie_name = (config_item('csrf_cookie_name')) ? config_item('csrf_cookie_name') : 'csrf_cookie_name';
- $this->csrf_expire = (config_item('csrf_expire')) ? config_item('csrf_expire') : 7200;
-
- // Append application specific cookie prefix to token name
- $this->csrf_cookie_name = (config_item('cookie_prefix')) ? config_item('cookie_prefix').$this->csrf_token_name : $this->csrf_token_name;
-
- // Set the CSRF hash
- $this->_csrf_set_hash();
-
- log_message('debug', "Security Class Initialized");
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Verify Cross Site Request Forgery Protection
- *
- * @access public
- * @return null
- */
- public function csrf_verify()
- {
- // If no POST data exists we will set the CSRF cookie
- if (count($_POST) == 0)
- {
- return $this->csrf_set_cookie();
- }
-
- // Do the tokens exist in both the _POST and _COOKIE arrays?
- if ( ! isset($_POST[$this->csrf_token_name]) OR ! isset($_COOKIE[$this->csrf_cookie_name]))
- {
- $this->csrf_show_error();
- }
-
- // Do the tokens match?
- if ($_POST[$this->csrf_token_name] != $_COOKIE[$this->csrf_cookie_name])
- {
- $this->csrf_show_error();
- }
-
- // We kill this since we're done and we don't want to polute the _POST array
- unset($_POST[$this->csrf_token_name]);
-
- // Nothing should last forever
- unset($_COOKIE[$this->csrf_cookie_name]);
- $this->_csrf_set_hash();
- $this->csrf_set_cookie();
-
- log_message('debug', "CSRF token verified ");
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Set Cross Site Request Forgery Protection Cookie
- *
- * @access public
- * @return null
- */
- public function csrf_set_cookie()
- {
- $expire = time() + $this->csrf_expire;
-
- setcookie($this->csrf_cookie_name, $this->csrf_hash, $expire, config_item('cookie_path'), config_item('cookie_domain'), 0);
-
- log_message('debug', "CRSF cookie Set");
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Set Cross Site Request Forgery Protection Cookie
- *
- * @access private
- * @return null
- */
- private function _csrf_set_hash()
- {
- if ($this->csrf_hash == '')
- {
- // If the cookie exists we will use it's 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]) AND $_COOKIE[$this->csrf_cookie_name] != '')
- {
- $this->csrf_hash = $_COOKIE[$this->csrf_cookie_name];
- }
- else
- {
- $this->csrf_hash = md5(uniqid(rand(), TRUE));
- }
- }
-
- return $this->csrf_hash;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Show CSRF Error
- *
- * @access public
- * @return null
- */
- public function csrf_show_error()
- {
- show_error('The action you have requested is not allowed.');
- }
-
- // --------------------------------------------------------------------
-
- /**
- * XSS Clean
- *
- * Sanitizes data so that Cross Site Scripting Hacks can be
- * prevented. This function does a fair amount of work but
- * it is extremely thorough, designed to prevent even the
- * most obscure XSS attempts. Nothing is ever 100% foolproof,
- * of course, but I haven't been able to get anything passed
- * the filter.
- *
- * Note: This function should only be used to deal with data
- * upon submission. It's not something that should
- * be used for general runtime processing.
- *
- * This function was based in part on some code and ideas I
- * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention
- *
- * To help develop this script I used this great list of
- * vulnerabilities along with a few other hacks I've
- * harvested from examining vulnerabilities in other programs:
- * http://ha.ckers.org/xss.html
- *
- * @access public
- * @param mixed string or array
- * @return string
- */
- public function xss_clean($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
- */
- $str = remove_invisible_characters($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;\\2", $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, '_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.
- *
- */
-
- 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 = preg_replace('/<\?(php)/i', "&lt;?\\1", $str);
- }
- else
- {
- $str = str_replace(array('<?', '?'.'>'), array('&lt;?', '?&gt;'), $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: &lt;blink&gt;
- *
- */
- $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&#40;'some code'&#41;
- *
- */
- $str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);
-
- /*
- * Final clean up
- *
- * This adds a bit of extra precaution in case
- * something got through the above filters
- *
- */
- foreach ($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 $str;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Random Hash for protecting URLs
- *
- * @access public
- * @return string
- */
- public function xss_hash()
- {
- if ($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 $this->xss_hash;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Compact Exploded Words
- *
- * Callback function for xss_clean() to remove whitespace from
- * things like j a v a s c r i p t
- *
- * @access private
- * @param type
- * @return type
- */
- private function _compact_exploded_words($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
- */
- private function _sanitize_naughty_html($matches)
- {
- // encode opening brace
- $str = '&lt;'.$matches[1].$matches[2].$matches[3];
-
- // encode captured opening or closing brace to prevent recursive vectors
- $str .= str_replace(array('>', '<'), array('&gt;', '&lt;'), $matches[4]);
-
- return $str;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * JS Link Removal
- *
- * Callback function for xss_clean() to sanitize links
- * This limits the PCRE backtracks, making it more performance friendly
- * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
- * PHP 5.2+ on link-heavy strings
- *
- * @access private
- * @param array
- * @return string
- */
- private function _js_link_removal($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), $match[0]);
- }
-
- /**
- * JS Image Removal
- *
- * Callback function for xss_clean() to sanitize image tags
- * This limits the PCRE backtracks, making it more performance friendly
- * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
- * PHP 5.2+ on image tag heavy strings
- *
- * @access private
- * @param array
- * @return string
- */
- private function _js_img_removal($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), $match[0]);
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Attribute Conversion
- *
- * Used as a callback for XSS Clean
- *
- * @access private
- * @param array
- * @return string
- */
- private function _convert_attribute($match)
- {
- return str_replace(array('>', '<', '\\'), array('&gt;', '&lt;', '\\\\'), $match[0]);
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Filter Attributes
- *
- * Filters tag attributes for consistency and safety
- *
- * @access private
- * @param string
- * @return string
- */
- private function _filter_attributes($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 $out;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * HTML Entity Decode Callback
- *
- * Used as a callback for XSS Clean
- *
- * @access private
- * @param array
- * @return string
- */
- private function _decode_entity($match)
- {
- return $this->entity_decode($match[0], strtoupper(config_item('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
- *
- * 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.
- *
- * @access public
- * @param string
- * @param string
- * @return string
- */
- public function 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 is_php('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 $str;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Filename Security
- *
- * @access public
- * @param string
- * @return string
- */
- public function sanitize_filename($str, $relative_path = FALSE)
- {
- $bad = array(
- "../",
- "<!--",
- "-->",
- "<",
- ">",
- "'",
- '"',
- '&',
- '$',
- '#',
- '{',
- '}',
- '[',
- ']',
- '=',
- ';',
- '?',
- "%20",
- "%22",
- "%3c", // <
- "%253c", // <
- "%3e", // >
- "%0e", // >
- "%28", // (
- "%29", // )
- "%2528", // (
- "%26", // &
- "%24", // $
- "%3f", // ?
- "%3b", // ;
- "%3d" // =
- );
-
- if ( ! $relative_path)
- {
- $bad[] = './';
- $bad[] = '/';
- }
-
- return stripslashes(str_replace($bad, '', $str));
- }
-
-}
-// END Security Class
-
-/* End of file Security.php */
-/* Location: ./system/libraries/Security.php */ \ No newline at end of file