diff options
Diffstat (limited to 'system/core/Security.php')
| -rwxr-xr-x | system/core/Security.php | 208 |
1 files changed, 121 insertions, 87 deletions
diff --git a/system/core/Security.php b/system/core/Security.php index 3617cadcc..a3e227437 100755 --- a/system/core/Security.php +++ b/system/core/Security.php @@ -25,14 +25,49 @@ * @link http://codeigniter.com/user_guide/libraries/security.html */ class CI_Security { - + + /** + * Random Hash for protecting URLs + * + * @var string + * @access protected + */ protected $_xss_hash = ''; + /** + * Random Hash for Cross Site Request Forgery Protection Cookie + * + * @var string + * @access protected + */ protected $_csrf_hash = ''; - protected $_csrf_expire = 7200; // Two hours (in seconds) + /** + * Expiration time for Cross Site Request Forgery Protection Cookie + * Defaults to two hours (in seconds) + * + * @var int + * @access protected + */ + protected $_csrf_expire = 7200; + /** + * Token name for Cross Site Request Forgery Protection Cookie + * + * @var string + * @access protected + */ protected $_csrf_token_name = 'ci_csrf_token'; + /** + * Cookie name for Cross Site Request Forgery Protection Cookie + * + * @var string + * @access protected + */ protected $_csrf_cookie_name = 'ci_csrf_token'; - - /* never allowed, string replacement */ + /** + * List of never allowed strings + * + * @var array + * @access protected + */ protected $_never_allowed_str = array( 'document.cookie' => '[removed]', 'document.write' => '[removed]', @@ -42,17 +77,24 @@ class CI_Security { '-moz-binding' => '[removed]', '<!--' => '<!--', '-->' => '-->', - '<![CDATA[' => '<![CDATA[' + '<![CDATA[' => '<![CDATA[', + '<comment>' => '<comment>' ); /* never allowed, regex replacement */ + /** + * List of never allowed regex replacement + * + * @var array + * @access protected + */ 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 */ @@ -95,7 +137,7 @@ class CI_Security { } // Do the tokens exist in both the _POST and _COOKIE arrays? - if ( ! isset($_POST[$this->_csrf_token_name]) OR + if ( ! isset($_POST[$this->_csrf_token_name]) OR ! isset($_COOKIE[$this->_csrf_cookie_name])) { $this->csrf_show_error(); @@ -107,7 +149,7 @@ class CI_Security { $this->csrf_show_error(); } - // We kill this since we're done and we don't want to + // We kill this since we're done and we don't want to // polute the _POST array unset($_POST[$this->_csrf_token_name]); @@ -117,7 +159,7 @@ class CI_Security { $this->csrf_set_cookie(); log_message('debug', "CSRF token verified "); - + return $this; } @@ -146,7 +188,7 @@ class CI_Security { setcookie($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 $this; } @@ -165,9 +207,9 @@ class CI_Security { // -------------------------------------------------------------------- /** - * Get CSRF Hash + * Get CSRF Hash * - * Getter Method + * Getter Method * * @return string self::_csrf_hash */ @@ -215,6 +257,7 @@ class CI_Security { * http://ha.ckers.org/xss.html * * @param mixed string or array + * @param bool * @return string */ public function xss_clean($str, $is_image = FALSE) @@ -263,7 +306,7 @@ class CI_Security { */ $str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str); - + $str = preg_replace_callback("/<\w+.*?(?=>|<|$)/si", array($this, '_decode_entity'), $str); /* @@ -276,7 +319,7 @@ class CI_Security { * * This prevents strings like this: ja vascript * NOTE: we deal with spaces between characters later. - * NOTE: preg_replace was found to be amazingly slow here on + * NOTE: preg_replace was found to be amazingly slow here on * large blocks of data, so we use str_replace. */ @@ -304,8 +347,8 @@ class CI_Security { */ if ($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 + // 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); } @@ -321,10 +364,10 @@ class CI_Security { * These words are compacted back to their correct state. */ $words = array( - 'javascript', 'expression', 'vbscript', 'script', + 'javascript', 'expression', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window' ); - + foreach ($words as $word) { $temp = ''; @@ -341,8 +384,8 @@ class CI_Security { /* * Remove disallowed Javascript in links or img tags - * We used to do some version comparisons and use of stripos for PHP5, - * but it is dog slow compared to these simplified non-capturing + * We used to do some version comparisons and use of stripos for PHP5, + * but it is dog slow compared to these simplified non-capturing * preg_match(), especially if the pattern exists in the string */ do @@ -405,11 +448,11 @@ class CI_Security { /* * Images are Handled in a Special Way - * - Essentially, we want to know that after all of the character - * conversion is done whether any unwanted, likely XSS, code was found. + * - Essentially, we want to know that after all of the character + * conversion is done whether any unwanted, likely XSS, code was found. * If not, we return TRUE, as the image is clean. - * However, if the string post-conversion does not matched the - * string post-removal of XSS, then it fails, as there was unwanted XSS + * However, if the string post-conversion does not matched the + * string post-removal of XSS, then it fails, as there was unwanted XSS * code found and removed/changed during processing. */ @@ -433,15 +476,7 @@ class CI_Security { { if ($this->_xss_hash == '') { - if (phpversion() >= 4.2) - { - mt_srand(); - } - else - { - mt_srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff); - } - + mt_srand(); $this->_xss_hash = md5(time() + mt_rand(0, 1999999999)); } @@ -455,14 +490,11 @@ class CI_Security { * * This function is a replacement for html_entity_decode() * - * In some versions of PHP the native function does not work - * when UTF-8 is the specified character set, so this gives us - * a work-around. More info here: - * http://bugs.php.net/bug.php?id=25670 - * - * NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the - * character set, and the PHP developers said they were not back porting the - * fix to versions other than PHP 5.x. + * The reason we are not using html_entity_decode() by itself is because + * while it is not technically correct to leave out the semicolon + * at the end of an entity most browsers will still interpret the entity + * correctly. html_entity_decode() does not convert entities without + * semicolons, so we are left with our own little solution here. Bummer. * * @param string * @param string @@ -470,33 +502,14 @@ class CI_Security { */ public function entity_decode($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; } - return $str; + $str = html_entity_decode($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)', $str); } // -------------------------------------------------------------------- @@ -505,6 +518,7 @@ class CI_Security { * Filename Security * * @param string + * @param bool * @return string */ public function sanitize_filename($str, $relative_path = FALSE) @@ -542,7 +556,7 @@ class CI_Security { "%3b", // ; "%3d" // = ); - + if ( ! $relative_path) { $bad[] = './'; @@ -570,7 +584,7 @@ class CI_Security { } // -------------------------------------------------------------------- - + /* * Remove Evil HTML Attributes (like evenhandlers and style) * @@ -578,7 +592,7 @@ class CI_Security { * - Everything up until a space * For example, everything between the pipes: * <a |style=document.write('hello');alert('world');| class=link> - * - Everything inside the quotes + * - Everything inside the quotes * For example, everything between the pipes: * <a |style="document.write('hello'); alert('world');"| class="link"> * @@ -589,7 +603,7 @@ class CI_Security { protected function _remove_evil_attributes($str, $is_image) { // All javascript event handlers (e.g. onload, onclick, onmouseover), style, and xmlns - $evil_attributes = array('on\w*', 'style', 'xmlns'); + $evil_attributes = array('on\w*', 'style', 'xmlns', 'formaction'); if ($is_image === TRUE) { @@ -601,16 +615,36 @@ class CI_Security { } do { - $str = preg_replace( - "#<(/?[^><]+?)([^A-Za-z\-])(".implode('|', $evil_attributes).")(\s*=\s*)([\"][^>]*?[\"]|[\'][^>]*?[\']|[^>]*?)([\s><])([><]*)#i", - "<$1$6", - $str, -1, $count - ); + $count = 0; + $attribs = array(); + + // find occurrences of illegal attribute strings without quotes + preg_match_all("/(".implode('|', $evil_attributes).")\s*=\s*([^\s]*)/is", $str, $matches, PREG_SET_ORDER); + + foreach ($matches as $attr) + { + $attribs[] = preg_quote($attr[0], '/'); + } + + // find occurrences of illegal attribute strings with quotes (042 and 047 are octal quotes) + preg_match_all("/(".implode('|', $evil_attributes).")\s*=\s*(\042|\047)([^\\2]*?)(\\2)/is", $str, $matches, PREG_SET_ORDER); + + foreach ($matches as $attr) + { + $attribs[] = preg_quote($attr[0], '/'); + } + + // replace illegal attribute strings that are inside an html tag + if (count($attribs) > 0) + { + $str = preg_replace("/<(\/?[^><]+?)([^A-Za-z\-])(".implode('|', $attribs).")([\s><])([><]*)/i", '<$1$2$4$5', $str, -1, $count); + } + } while ($count); return $str; } - + // -------------------------------------------------------------------- /** @@ -627,7 +661,7 @@ class CI_Security { $str = '<'.$matches[1].$matches[2].$matches[3]; // encode captured opening or closing brace to prevent recursive vectors - $str .= str_replace(array('>', '<'), array('>', '<'), + $str .= str_replace(array('>', '<'), array('>', '<'), $matches[4]); return $str; @@ -649,7 +683,7 @@ class CI_Security { protected function _js_link_removal($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), $match[0]); } @@ -669,7 +703,7 @@ class CI_Security { protected function _js_img_removal($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), $match[0]); } @@ -729,13 +763,13 @@ class CI_Security { } // -------------------------------------------------------------------- - + /** * Validate URL entities * * Called by xss_clean() * - * @param string + * @param string * @return string */ protected function _validate_entities($str) @@ -743,9 +777,9 @@ class CI_Security { /* * Protect GET variables in URLs */ - + // 901119URL5918AMP18930PROTECT8198 - + $str = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-]+)|i', $this->xss_hash()."\\1=\\2", $str); /* @@ -769,7 +803,7 @@ class CI_Security { * Un-Protect GET variables in URLs */ $str = str_replace($this->xss_hash(), '&', $str); - + return $str; } @@ -794,7 +828,7 @@ class CI_Security { { $str = preg_replace("#".$key."#i", $val, $str); } - + return $str; } @@ -809,16 +843,16 @@ class CI_Security { { if ($this->_csrf_hash == '') { - // If the cookie exists we will use it's value. + // 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 + // each page load since a page could contain embedded // sub-pages causing this feature to fail - if (isset($_COOKIE[$this->_csrf_cookie_name]) && + 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)); } |