added Security library
diff --git a/system/libraries/Security.php b/system/libraries/Security.php
new file mode 100644
index 0000000..93da592
--- /dev/null
+++ b/system/libraries/Security.php
@@ -0,0 +1,710 @@
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 4.3.2 or newer
+ *
+ * @package CodeIgniter
+ * @author ExpressionEngine Dev Team
+ * @copyright Copyright (c) 2008 - 2010, 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 {
+ var $xss_hash = '';
+ var $csrf_hash = '';
+ var $csrf_expire = 7200; // Two hours (in seconds)
+ var $csrf_token_name = 'ci_csrf_token';
+
+ /* never allowed, string replacement */
+ var $never_allowed_str = array(
+ 'document.cookie' => '[removed]',
+ 'document.write' => '[removed]',
+ '.parentNode' => '[removed]',
+ '.innerHTML' => '[removed]',
+ 'window.location' => '[removed]',
+ '-moz-binding' => '[removed]',
+ '<!--' => '<!--',
+ '-->' => '-->',
+ '<![CDATA[' => '<![CDATA['
+ );
+ /* never allowed, regex replacement */
+ var $never_allowed_regex = array(
+ "javascript\s*:" => '[removed]',
+ "expression\s*(\(|&\#40;)" => '[removed]', // CSS and IE
+ "vbscript\s*:" => '[removed]', // IE, surprise!
+ "Redirect\s+302" => '[removed]'
+ );
+
+ function CI_Security()
+ {
+ // Set the CSRF hash
+ $this->_csrf_set_hash();
+
+ log_message('debug', "Security Class Initialized");
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Verify Cross Site Request Forgery Protection
+ *
+ * @access public
+ * @return null
+ */
+ function csrf_verify()
+ {
+ // If no POST data exists we will set the CSRF cookie
+ if (count($_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_token_name]))
+ {
+ $this->csrf_show_error();
+ }
+
+ // Do the tokens match?
+ if ($_POST[$this->csrf_token_name] != $_COOKIE[$this->csrf_token_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]);
+
+ log_message('debug', "CSRF token verified ");
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set Cross Site Request Forgery Protection Cookie
+ *
+ * @access public
+ * @return null
+ */
+ function csrf_set_cookie()
+ {
+ $prefix = ( ! is_string(config_item('cookie_prefix'))) ? '' : config_item('cookie_prefix');
+
+ $expire = time() + $this->csrf_expire;
+
+ setcookie($prefix.$this->csrf_token_name, $this->csrf_hash, $expire, config_item('cookie_path'), config_item('cookie_domain'), 0);
+
+ log_message('debug', "CRSF cookie Set");
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Set Cross Site Request Forgery Protection Cookie
+ *
+ * @access public
+ * @return null
+ */
+ function _csrf_set_hash()
+ {
+ if ($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_token_name]) AND $_COOKIE[$this->csrf_token_name] != '')
+ {
+ $this->csrf_hash = $_COOKIE[$this->csrf_token_name];
+ }
+ else
+ {
+ $this->csrf_hash = md5(uniqid(rand(), TRUE));
+ }
+ }
+
+ return $this->csrf_hash;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Show CSRF Error
+ *
+ * @access public
+ * @return null
+ */
+ function csrf_show_error()
+ {
+ show_error('The action you have requested is not allowed.');
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XSS Clean
+ *
+ * Sanitizes data so that Cross Site Scripting Hacks can be
+ * prevented. This function does a fair amount of work but
+ * it is extremely thorough, designed to prevent even the
+ * most obscure XSS attempts. Nothing is ever 100% foolproof,
+ * of course, but I haven't been able to get anything passed
+ * the filter.
+ *
+ * Note: This function should only be used to deal with data
+ * upon submission. It's not something that should
+ * be used for general runtime processing.
+ *
+ * This function was based in part on some code and ideas I
+ * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention
+ *
+ * To help develop this script I used this great list of
+ * vulnerabilities along with a few other hacks I've
+ * harvested from examining vulnerabilities in other programs:
+ * http://ha.ckers.org/xss.html
+ *
+ * @access public
+ * @param mixed string or array
+ * @return string
+ */
+ function xss_clean($str, $is_image = FALSE)
+ {
+ /*
+ * Is the string an array?
+ *
+ */
+ if (is_array($str))
+ {
+ while (list($key) = each($str))
+ {
+ $str[$key] = $this->xss_clean($str[$key]);
+ }
+
+ return $str;
+ }
+
+ /*
+ * Remove Invisible Characters
+ */
+ $str = $this->_remove_invisible_characters($str);
+
+ /*
+ * Protect GET variables in URLs
+ */
+
+ // 901119URL5918AMP18930PROTECT8198
+
+ $str = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-]+)|i', $this->xss_hash()."\\1=\\2", $str);
+
+ /*
+ * Validate standard character entities
+ *
+ * Add a semicolon if missing. We do this to enable
+ * the conversion of entities to ASCII later.
+ *
+ */
+ $str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\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 = $this->_remove_invisible_characters($str);
+
+ /*
+ * Convert all tabs to spaces
+ *
+ * This prevents strings like this: ja vascript
+ * NOTE: we deal with spaces between characters later.
+ * NOTE: preg_replace was found to be amazingly slow here on large blocks of data,
+ * so we use str_replace.
+ *
+ */
+
+ if (strpos($str, "\t") !== FALSE)
+ {
+ $str = str_replace("\t", ' ', $str);
+ }
+
+ /*
+ * Capture converted string for later comparison
+ */
+ $converted_string = $str;
+
+ /*
+ * Not Allowed Under Any Conditions
+ */
+
+ foreach ($this->never_allowed_str as $key => $val)
+ {
+ $str = str_replace($key, $val, $str);
+ }
+
+ foreach ($this->never_allowed_regex as $key => $val)
+ {
+ $str = preg_replace("#".$key."#i", $val, $str);
+ }
+
+ /*
+ * Makes PHP tags safe
+ *
+ * Note: XML tags are inadvertently replaced too:
+ *
+ * <?xml
+ *
+ * But it doesn't seem to pose a problem.
+ *
+ */
+ if ($is_image === TRUE)
+ {
+ // Images have a tendency to have the PHP short opening and closing tags every so often
+ // so we skip those and only do the long opening tags.
+ $str = 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 JavaScript Event Handlers
+ *
+ * Note: This code is a little blunt. It removes
+ * the event handler and anything up to the closing >,
+ * but it's unlikely to be a problem.
+ *
+ */
+ $event_handlers = array('[^a-z_\-]on\w*','xmlns');
+
+ if ($is_image === TRUE)
+ {
+ /*
+ * Adobe Photoshop puts XML metadata into JFIF images, including namespacing,
+ * so we have to allow this for images. -Paul
+ */
+ unset($event_handlers[array_search('xmlns', $event_handlers)]);
+ }
+
+ $str = preg_replace("#<([^><]+?)(".implode('|', $event_handlers).")(\s*=\s*[^><]*)([><]*)#i", "<\\1\\4", $str);
+
+ /*
+ * Sanitize naughty HTML elements
+ *
+ * If a tag containing any of the words in the list
+ * below is found, the tag gets converted to entities.
+ *
+ * So this: <blink>
+ * Becomes: <blink>
+ *
+ */
+ $naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|isindex|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';
+ $str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);
+
+ /*
+ * Sanitize naughty scripting elements
+ *
+ * Similar to above, only instead of looking for
+ * tags it looks for PHP and JavaScript commands
+ * that are disallowed. Rather than removing the
+ * code, it simply converts the parenthesis to entities
+ * rendering the code un-executable.
+ *
+ * For example: eval('some code')
+ * Becomes: eval('some code')
+ *
+ */
+ $str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2(\\3)", $str);
+
+ /*
+ * Final clean up
+ *
+ * This adds a bit of extra precaution in case
+ * something got through the above filters
+ *
+ */
+ foreach ($this->never_allowed_str as $key => $val)
+ {
+ $str = str_replace($key, $val, $str);
+ }
+
+ foreach ($this->never_allowed_regex as $key => $val)
+ {
+ $str = preg_replace("#".$key."#i", $val, $str);
+ }
+
+ /*
+ * Images are Handled in a Special Way
+ * - Essentially, we want to know that after all of the character conversion is done whether
+ * any unwanted, likely XSS, code was found. If not, we return TRUE, as the image is clean.
+ * However, if the string post-conversion does not matched the string post-removal of XSS,
+ * then it fails, as there was unwanted XSS code found and removed/changed during processing.
+ */
+
+ if ($is_image === TRUE)
+ {
+ if ($str == $converted_string)
+ {
+ return TRUE;
+ }
+ else
+ {
+ return FALSE;
+ }
+ }
+
+ log_message('debug', "XSS Filtering completed");
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Random Hash for protecting URLs
+ *
+ * @access public
+ * @return string
+ */
+ function xss_hash()
+ {
+ if ($this->xss_hash == '')
+ {
+ if (phpversion() >= 4.2)
+ mt_srand();
+ else
+ mt_srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff);
+
+ $this->xss_hash = md5(time() + mt_rand(0, 1999999999));
+ }
+
+ return $this->xss_hash;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Remove Invisible Characters
+ *
+ * This prevents sandwiching null characters
+ * between ascii characters, like Java\0script.
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function _remove_invisible_characters($str)
+ {
+ static $non_displayables;
+
+ if ( ! isset($non_displayables))
+ {
+ // every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),
+ $non_displayables = array(
+ '/%0[0-8bcef]/', // url encoded 00-08, 11, 12, 14, 15
+ '/%1[0-9a-f]/', // url encoded 16-31
+ '/[\x00-\x08]/', // 00-08
+ '/\x0b/', '/\x0c/', // 11, 12
+ '/[\x0e-\x1f]/' // 14-31
+ );
+ }
+
+ do
+ {
+ $cleaned = $str;
+ $str = preg_replace($non_displayables, '', $str);
+ }
+ while ($cleaned != $str);
+
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Compact Exploded Words
+ *
+ * Callback function for xss_clean() to remove whitespace from
+ * things like j a v a s c r i p t
+ *
+ * @access public
+ * @param type
+ * @return type
+ */
+ function _compact_exploded_words($matches)
+ {
+ return preg_replace('/\s+/s', '', $matches[1]).$matches[2];
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Sanitize Naughty HTML
+ *
+ * Callback function for xss_clean() to remove naughty HTML elements
+ *
+ * @access private
+ * @param array
+ * @return string
+ */
+ function _sanitize_naughty_html($matches)
+ {
+ // encode opening brace
+ $str = '<'.$matches[1].$matches[2].$matches[3];
+
+ // encode captured opening or closing brace to prevent recursive vectors
+ $str .= str_replace(array('>', '<'), array('>', '<'), $matches[4]);
+
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * JS Link Removal
+ *
+ * Callback function for xss_clean() to sanitize links
+ * This limits the PCRE backtracks, making it more performance friendly
+ * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
+ * PHP 5.2+ on link-heavy strings
+ *
+ * @access private
+ * @param array
+ * @return string
+ */
+ function _js_link_removal($match)
+ {
+ $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
+ return str_replace($match[1], preg_replace("#href=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
+ }
+
+ /**
+ * JS Image Removal
+ *
+ * Callback function for xss_clean() to sanitize image tags
+ * This limits the PCRE backtracks, making it more performance friendly
+ * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
+ * PHP 5.2+ on image tag heavy strings
+ *
+ * @access private
+ * @param array
+ * @return string
+ */
+ function _js_img_removal($match)
+ {
+ $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
+ return str_replace($match[1], preg_replace("#src=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Attribute Conversion
+ *
+ * Used as a callback for XSS Clean
+ *
+ * @access public
+ * @param array
+ * @return string
+ */
+ function _convert_attribute($match)
+ {
+ return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Filter Attributes
+ *
+ * Filters tag attributes for consistency and safety
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function _filter_attributes($str)
+ {
+ $out = '';
+
+ if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches))
+ {
+ foreach ($matches[0] as $match)
+ {
+ $out .= preg_replace("#/\*.*?\*/#s", '', $match);
+ }
+ }
+
+ return $out;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entity Decode Callback
+ *
+ * Used as a callback for XSS Clean
+ *
+ * @access public
+ * @param array
+ * @return string
+ */
+ function _decode_entity($match)
+ {
+ $CI =& get_instance();
+ $CI->load->helper('typography');
+ return entity_decode($match[0], strtoupper($CI->config->item('charset')));
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Filename Security
+ *
+ * @access public
+ * @param string
+ * @return string
+ */
+ function sanitize_filename($str)
+ {
+ $bad = array(
+ "../",
+ "./",
+ "<!--",
+ "-->",
+ "<",
+ ">",
+ "'",
+ '"',
+ '&',
+ '$',
+ '#',
+ '{',
+ '}',
+ '[',
+ ']',
+ '=',
+ ';',
+ '?',
+ '/',
+ "%20",
+ "%22",
+ "%3c", // <
+ "%253c", // <
+ "%3e", // >
+ "%0e", // >
+ "%28", // (
+ "%29", // )
+ "%2528", // (
+ "%26", // &
+ "%24", // $
+ "%3f", // ?
+ "%3b", // ;
+ "%3d" // =
+ );
+
+ 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