--- /dev/null
+<?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/security.html
+ */
+class CI_Security {
+
+ protected $_xss_hash = '';
+ protected $_csrf_hash = '';
+ protected $_csrf_expire = 7200; // Two hours (in seconds)
+ protected $_csrf_token_name = 'ci_csrf_token';
+ protected $_csrf_cookie_name = 'ci_csrf_token';
+
+ /* never allowed, string replacement */
+ protected $_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 */
+ protected $_never_allowed_regex = array(
+ "javascript\s*:" => '[removed]',
+ "expression\s*(\(|&\#40;)" => '[removed]', // CSS and IE
+ "vbscript\s*:" => '[removed]', // IE, surprise!
+ "Redirect\s+302" => '[removed]'
+ );
+
+ /**
+ * Constructor
+ */
+ public function __construct()
+ {
+ // 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
+ $this->_csrf_set_hash();
+
+ log_message('debug', "Security Class Initialized");
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Verify Cross Site Request Forgery Protection
+ *
+ * @return object
+ */
+ public function csrf_verify()
+ {
+ // If no POST data exists we will set the CSRF cookie
+ if (count($_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 ");
+
+ return $this;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set Cross Site Request Forgery Protection Cookie
+ *
+ * @return object
+ */
+ public function csrf_set_cookie()
+ {
+ $expire = time() + $this->_csrf_expire;
+ $secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0;
+
+ if ($secure_cookie)
+ {
+ $req = isset($_SERVER['HTTPS']) ? $_SERVER['HTTPS'] : FALSE;
+
+ if ( ! $req OR $req == 'off')
+ {
+ return FALSE;
+ }
+ }
+
+ setcookie($this->_csrf_cookie_name, $this->_csrf_hash, $expire, config_item('cookie_path'), config_item('cookie_domain'), $secure_cookie);
+
+ log_message('debug', "CRSF cookie Set");
+
+ return $this;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Show CSRF Error
+ *
+ * @return void
+ */
+ public function csrf_show_error()
+ {
+ show_error('The action you have requested is not allowed.');
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Get CSRF Hash
+ *
+ * Getter Method
+ *
+ * @return string self::_csrf_hash
+ */
+ public function get_csrf_hash()
+ {
+ return $this->_csrf_hash;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Get CSRF Token Name
+ *
+ * Getter Method
+ *
+ * @return string self::csrf_token_name
+ */
+ public function get_csrf_token_name()
+ {
+ return $this->_csrf_token_name;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XSS Clean
+ *
+ * Sanitizes data so that Cross Site Scripting Hacks can be
+ * prevented. This function does a fair amount of work but
+ * it is extremely thorough, designed to prevent even the
+ * most obscure XSS attempts. Nothing is ever 100% foolproof,
+ * of course, but I haven't been able to get anything passed
+ * the filter.
+ *
+ * Note: This function should only be used to deal with data
+ * upon submission. It's not something that should
+ * be used for general runtime processing.
+ *
+ * This function was based in part on some code and ideas I
+ * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention
+ *
+ * To help develop this script I used this great list of
+ * vulnerabilities along with a few other hacks I've
+ * harvested from examining vulnerabilities in other programs:
+ * http://ha.ckers.org/xss.html
+ *
+ * @param mixed string or array
+ * @return string
+ */
+ public function xss_clean($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);
+
+ // Validate Entities in URLs
+ $str = $this->_validate_entities($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;
+
+ // 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.
+ */
+ $words = array(
+ 'javascript', 'expression', 'vbscript', 'script',
+ 'applet', 'alert', 'document', 'write', 'cookie', 'window'
+ );
+
+ foreach ($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 evil attributes such as style, onclick and xmlns
+ $str = $this->_remove_evil_attributes($str, $is_image);
+
+ /*
+ * 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
+ $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) ? TRUE: FALSE;
+ }
+
+ log_message('debug', "XSS Filtering completed");
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Random Hash for protecting URLs
+ *
+ * @return string
+ */
+ public function xss_hash()
+ {
+ if ($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 $this->_xss_hash;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entities Decode
+ *
+ * This function is a replacement for html_entity_decode()
+ *
+ * In some versions of PHP the native function does not work
+ * when UTF-8 is the specified character set, so this gives us
+ * a work-around. More info here:
+ * http://bugs.php.net/bug.php?id=25670
+ *
+ * NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
+ * character set, and the PHP developers said they were not back porting the
+ * fix to versions other than PHP 5.x.
+ *
+ * @param string
+ * @param string
+ * @return string
+ */
+ public function entity_decode($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'))
+ {
+ $str = html_entity_decode($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 $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Filename Security
+ *
+ * @param string
+ * @return string
+ */
+ public function sanitize_filename($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[] = '/';
+ }
+
+ $str = remove_invisible_characters($str, FALSE);
+ return stripslashes(str_replace($bad, '', $str));
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * Compact Exploded Words
+ *
+ * Callback function for xss_clean() to remove whitespace from
+ * things like j a v a s c r i p t
+ *
+ * @param type
+ * @return type
+ */
+ protected function _compact_exploded_words($matches)
+ {
+ return preg_replace('/\s+/s', '', $matches[1]).$matches[2];
+ }
+
+ // --------------------------------------------------------------------
+
+ /*
+ * Remove Evil HTML Attributes (like evenhandlers and style)
+ *
+ * It removes the evil attribute and either:
+ * - Everything up until a space
+ * For example, everything between the pipes:
+ * <a |style=document.write('hello');alert('world');| class=link>
+ * - Everything inside the quotes
+ * For example, everything between the pipes:
+ * <a |style="document.write('hello'); alert('world');"| class="link">
+ *
+ * @param string $str The string to check
+ * @param boolean $is_image TRUE if this is an image
+ * @return string The string with the evil attributes removed
+ */
+ protected function _remove_evil_attributes($str, $is_image)
+ {
+ // All javascript event handlers (e.g. onload, onclick, onmouseover), style, and xmlns
+ $evil_attributes = array('on\w*', 'style', 'xmlns');
+
+ if ($is_image === TRUE)
+ {
+ /*
+ * Adobe Photoshop puts XML metadata into JFIF images,
+ * including namespacing, so we have to allow this for images.
+ */
+ unset($evil_attributes[array_search('xmlns', $evil_attributes)]);
+ }
+
+ do {
+ $str = preg_replace(
+ "#<(/?[^><]+?)([^A-Za-z\-])(".implode('|', $evil_attributes).")(\s*=\s*)([\"][^>]*?[\"]|[\'][^>]*?[\']|[^>]*?)([\s><])([><]*)#i",
+ "<$1$6",
+ $str, -1, $count
+ );
+ } while ($count);
+
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Sanitize Naughty HTML
+ *
+ * Callback function for xss_clean() to remove naughty HTML elements
+ *
+ * @param array
+ * @return string
+ */
+ protected function _sanitize_naughty_html($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 $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * JS Link Removal
+ *
+ * Callback function for xss_clean() to sanitize links
+ * This limits the PCRE backtracks, making it more performance friendly
+ * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
+ * PHP 5.2+ on link-heavy strings
+ *
+ * @param array
+ * @return string
+ */
+ protected function _js_link_removal($match)
+ {
+ $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
+
+ return str_replace($match[1], preg_replace("#href=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * JS Image Removal
+ *
+ * Callback function for xss_clean() to sanitize image tags
+ * This limits the PCRE backtracks, making it more performance friendly
+ * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
+ * PHP 5.2+ on image tag heavy strings
+ *
+ * @param array
+ * @return string
+ */
+ protected function _js_img_removal($match)
+ {
+ $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
+
+ return str_replace($match[1], preg_replace("#src=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Attribute Conversion
+ *
+ * Used as a callback for XSS Clean
+ *
+ * @param array
+ * @return string
+ */
+ protected function _convert_attribute($match)
+ {
+ return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Filter Attributes
+ *
+ * Filters tag attributes for consistency and safety
+ *
+ * @param string
+ * @return string
+ */
+ protected function _filter_attributes($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 $out;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entity Decode Callback
+ *
+ * Used as a callback for XSS Clean
+ *
+ * @param array
+ * @return string
+ */
+ protected function _decode_entity($match)
+ {
+ return $this->entity_decode($match[0], strtoupper(config_item('charset')));
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Validate URL entities
+ *
+ * Called by xss_clean()
+ *
+ * @param string
+ * @return string
+ */
+ protected function _validate_entities($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);
+
+ return $str;
+ }
+
+ // ----------------------------------------------------------------------
+
+ /**
+ * Do Never Allowed
+ *
+ * A utility function for xss_clean()
+ *
+ * @param string
+ * @return string
+ */
+ protected function _do_never_allowed($str)
+ {
+ 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);
+ }
+
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set Cross Site Request Forgery Protection Cookie
+ *
+ * @return string
+ */
+ protected function _csrf_set_hash()
+ {
+ if ($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]) &&
+ $_COOKIE[$this->_csrf_cookie_name] != '')
+ {
+ return $this->_csrf_hash = $_COOKIE[$this->_csrf_cookie_name];
+ }
+
+ return $this->_csrf_hash = md5(uniqid(rand(), TRUE));
+ }
+
+ return $this->_csrf_hash;
+ }
+
+}
+// END Security Class
+
+/* End of file Security.php */
+/* Location: ./system/libraries/Security.php */
\ No newline at end of file
projects / living-lab-site.git / blobdiff