[php] <?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 * 本類包含一些方法，能幫助您創建安全的應用程序，對輸入的數據進行安全方面的處理。 * CI官方手冊本類的地址：http://codeigniter.org.cn/user_guide/libraries/security.html * @package CodeIgniter * @subpackage Libraries * @category Security * @author ExpressionEngine Dev Team * @link http://codeigniter.com/user_guide/libraries/security.html */ class CI_Security { /** * Random Hash for protecting URLs * 為保護URL（跨站腳本攻擊）的隨機hash值 * @var string * @access protected */ protected $_xss_hash = ''; /** * Random Hash for Cross Site Request Forgery Protection Cookie * 防止跨站請求偽造cookie的隨機hash * @var string * @access protected */ protected $_csrf_hash = ''; /** * Expiration time for Cross Site Request Forgery Protection Cookie * Defaults to two hours (in seconds) * 跨站請求保護Cookie的過期時間，默認是2小時（單位秒） * @var int * @access protected */ protected $_csrf_expire = 7200; /** * Token name for Cross Site Request Forgery 偽造 Protection Cookie * 跨站請求偽造保護的Cookie令牌名 * @var string * @access protected */ protected $_csrf_token_name = 'ci_csrf_token'; /** * Cookie name for Cross Site Request Forgery Protection Cookie * 跨站請求偽造保護的Cookie的Cookie名 * @var string * @access protected */ protected $_csrf_cookie_name = 'ci_csrf_token'; /** * List of never allowed strings * 決不允許的字符串的列表 * @var array * @access protected */ protected $_never_allowed_str = array( 'document.cookie' => '[removed]', 'document.write' => '[removed]', '.parentNode' => '[removed]', '.innerHTML' => '[removed]', 'window.location' => '[removed]', '-moz-binding' => '[removed]', '<!--' => '<!--', '-->' => '-->', '<![CDATA[' => '<![CDATA[', '<comment>' => '<comment>' ); /* never allowed, regex replacement */ /** * List of never allowed regex replacement * 不允許的正則替換字符串列表 * @var array * @access protected */ protected $_never_allowed_regex = array( 'javascript\s*:', 'expression\s*(\(|&\#40;)', // CSS and IE 'vbscript\s*:', // IE, surprise! 'Redirect\s+302', "([\"'])?data\s*:[^\\1]*?base64[^\\1]*?,[^\\1]*?\\1?" ); /** * Constructor * * @return void */ public function __construct() { // Is CSRF protection enabled? // csrf 是否開啟 if (config_item('csrf_protection') === TRUE) { // CSRF config 讀取CSRF 配置並賦值給本類下的對應的屬性 foreach (array('csrf_expire', 'csrf_token_name', 'csrf_cookie_name') as $key) { if (FALSE !== ($val = config_item($key))) { $this->{'_'.$key} = $val; } } // Append application specific cookie prefix // 添加應用指定的cookie前綴 if (config_item('cookie_prefix')) { $this->_csrf_cookie_name = config_item('cookie_prefix').$this->_csrf_cookie_name; } // Set the CSRF hash // 設置CSRF hash $this->_csrf_set_hash(); } log_message('debug', "Security Class Initialized"); } // -------------------------------------------------------------------- /** * Verify Cross Site Request Forgery Protection * 驗證跨站請求偽造保護 * @return object */ public function csrf_verify() { // If it's not a POST request we will set the CSRF cookie // 如果不是post請求我們要設置 CSRF cookie if (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST') { return $this->csrf_set_cookie(); } // Do the tokens exist in both the _POST and _COOKIE arrays? // 如果請求令牌不存在，調用csrf_show_error 報錯 if ( ! isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name])) { $this->csrf_show_error(); } // Do the tokens match? // 如果令牌不對，報錯。 if ($_POST[$this->_csrf_token_name] != $_COOKIE[$this->_csrf_cookie_name]) { $this->csrf_show_error(); } // We kill this since we're done and we don't want to // polute the _POST array // 銷毀領牌子，因為我們不想污染_POST 數組 unset($_POST[$this->_csrf_token_name]); // Nothing should last forever // 銷毀cookie名 並重新設置hash和cookie unset($_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 * 設置偽造cookie保護跨站請求 * @return object */ public function csrf_set_cookie() { $expire = time() + $this->_csrf_expire; $secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0; // 當存在https時設置cookie if ($secure_cookie && (emptyempty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) === 'off')) { return FALSE; } // 設置cookie 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 * 顯示CSRF錯誤 * @return void */ public function csrf_show_error() { show_error('The action you have requested is not allowed.'); } // -------------------------------------------------------------------- /** * Get CSRF Hash * 獲取CSRF hash * Getter Method * * @return string self::_csrf_hash */ public function get_csrf_hash() { return $this->_csrf_hash; } // -------------------------------------------------------------------- /** * Get CSRF Token Name * 獲取CSRF 令排名 * Getter Method * * @return string self::csrf_token_name */ public function get_csrf_token_name() { return $this->_csrf_token_name; } // -------------------------------------------------------------------- /** * XSS Clean * * Sanitizes 清理 data so that Cross Site Scripting Hacks can be * prevented.阻止 This function does a fair amount of work but * it is extremely thorough, designed to prevent even the * most obscure XSS attempts 企圖. Nothing is ever 100% foolproof, * of course, but I haven't been able to get anything passed * the filter. * 對數據進行過濾，從而可以防止跨站腳本攻擊。這個函數做了一些工作，但是它是非常徹底的， * 甚至可以防止大多數模糊的XSS企圖。當然，沒有什麼是100%安全的， * 但是我們在這個過濾器中已經做了所欲我們所能做想到的了。 * * Note: This function should only be used to deal with data * upon submission. It's not something that should * be used for general runtime processing. * 注意：這個函數只能用來處理已經提交的數據。 * 在通常的運行過程中，不應該使用該函數。 * * This function was based in part on some code and ideas I * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention * * To help develop this script I used this great list of * vulnerabilities along with a few other hacks I've * harvested from examining vulnerabilities in other programs: * http://ha.ckers.org/xss.html * * @param mixed string or array * @param bool * @return string */ public function xss_clean($str, $is_image = FALSE) { /* * Is the string an array? * 需要過濾的字符串是數組嗎？ * */ if (is_array($str)) { while (list($key) = each($str)) { $str[$key] = $this->xss_clean($str[$key]); } return $str; } /* * Remove Invisible Characters * 移除不可見字符 */ $str = remove_invisible_characters($str); // Validate Entities in URLs // 驗證在URL中的字符實體 $str = $this->_validate_entities($str); /* * URL Decode * URL解碼 * Just in case stuff like this is submitted: * 防止下面這樣的東西提交 * <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 * rawurldecode() 不會把加號（'+'）解碼為空格，而 urldecode() 可以。 * */ $str = rawurldecode($str); /* * Convert character entities to ASCII * 把實體字符轉換成ASCII碼 * 這使得我們下面的測試是可靠的，我們僅僅轉換實體內的標簽，因為這些是會造成安全問題的實體 * 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! * 再次刪除不可見字符 */ $str = remove_invisible_characters($str); /* * Convert all tabs to spaces * 轉換所有制表符為空格 * This prevents strings like this: ja vascript * 這用來防止字符串類似於ja vascript * NOTE: we deal with spaces between characters later. * 注意： 我們將在後面處理字符之間的空格 * NOTE: preg_replace was found to be amazingly slow here on * large blocks of data, so we use str_replace. * 注意：preg_replace在這裡是極其緩慢的對於大塊的數據，所以使用str_replace * */ if (strpos($str, "\t") !== FALSE) { $str = str_replace("\t", ' ', $str); } /* * Capture 捕獲 converted string for later comparison * 為以後的比較捕獲轉換的字符串 */ $converted_string = $str; // Remove Strings that are never allowed // 刪除絕不容許的字符串 $str = $this->_do_never_allowed($str); /* * Makes PHP tags safe * 使PHP標簽安全 * Note: XML tags are inadvertently replaced too: * 注意： XML標簽也會被無意的替換 * <?xml * * But it doesn't seem to pose a problem. * 但是它似乎不會構成問題 */ 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 * 壓縮所有分解了的單詞 * This corrects words like: j a v a s c r i p t * These words are compacted back to their correct state. */ $words = array( 'javascript', 'expression', 'vbscript', 'script', 'base64', 'applet', 'alert', 'document', 'write', 'cookie', 'window' ); foreach ($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 * 移除在鏈接和圖片標簽中不允許的javascript代碼 * We used to do some version comparisons and use of stripos for PHP5, * 我們通常在PHP5中使用stripos做一些版本的比較， * but it is dog slow compared to these simplified non-capturing * 但是特別是當模式在字符串中存在的時候，它要比非捕獲的preg_match()慢很多 * 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 // 移除有害的屬性，比如style ， onclick ， xmlns $str = $this->_remove_evil_attributes($str, $is_image); /* * Sanitize naughty HTML elements * 清理不適當的HTML元素 * If a tag containing any of the words in the list * below is found, the tag gets converted to entities. * 如果一個標簽包含任何一個下面列表中的單詞，這個標簽轉換為一個字符實體 * 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 * 清理不合法的腳本元素 * 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. * 上面的類似，僅僅替換查詢到的類似於PHP和Javascript命令的不被允許的標簽 * 勝過移除這些代碼，轉換這些代碼為不可執行的實體更好 * * 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 // 最後的清理 // This adds a bit of extra precaution in case // something got through the above filters // 額外預防，防止上面的處理產生不合法的字符 $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 $str; } // -------------------------------------------------------------------- /** * Random Hash for protecting URLs * 隨即生成一個_xss_hssh * @return string */ public function xss_hash() { if ($this->_xss_hash == '') { mt_srand(); $this->_xss_hash = md5(time() + mt_rand(0, 1999999999)); } return $this->_xss_hash; } // -------------------------------------------------------------------- /** * HTML Entities Decode * HTML 實體解碼 * This function is a replacement for html_entity_decode() * 這個函數用來替換 html_entity_decode()函數 * The reason we are not using html_entity_decode() by itself is because * while it is not technically技術上 correct to leave out the semicolon * at the end of an entity most browsers will still interpret the entity * correctly. html_entity_decode() does not convert entities without * semicolons, so we are left with our own little solution here. Bummer. * 當編碼字符後沒有寫；時，大部分浏覽器都能夠正確的解釋代碼，但是，html_entity_decode將不會解釋它 * html_entity_decode()不會轉換沒有分號的實體，所以使用自己的解決方案 * @param string * @param string * @return string */ public function entity_decode($str, $charset='UTF-8') { if (stristr($str, '&') === FALSE) { 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)', $str); } // -------------------------------------------------------------------- /** * Filename Security * 文件名安全 * @param string * @param bool * @return string */ public function sanitize_filename($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, '', $str)); } // ---------------------------------------------------------------- /** * Compact Exploded Words * 壓縮搜索到得單詞 * Callback function for xss_clean() to remove whitespace from * things like j a v a s c r i p t * 回調函數，用於xss_clean()，從類似於 j a v a s c r i p t中移除空格 * * * @param type * @return type */ protected function _compact_exploded_words($matches) { return preg_replace('/\s+/s', '', $matches[1]).$matches[2]; } // -------------------------------------------------------------------- /* * Remove Evil HTML Attributes (like evenhandlers and style) * 移除有害的html屬性，（像事件處理和樣式） * 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 // 所有的havascript事件處理器 $evil_attributes = array('on\w*', 'style', 'xmlns', 'formaction'); if ($is_image === TRUE) { /* * Adobe Photoshop puts XML metadata into JFIF images, * including namespacing, so we have to allow this for images. * Adobe Photoshop在JFIF圖片中放入了XML元數據 * 包含命名空間，所以我們必須對圖片允許這些 */ unset($evil_attributes[array_search('xmlns', $evil_attributes)]); } do { $count = 0; $attribs = array(); // find occurrences of illegal attribute strings without quotes // 找出沒有加引號的的不合法的屬性 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 非法 attribute strings with quotes (042 and 047 are octal quotes) // 找出沒有引號的不合法屬性（042，4,0是八進制引號） 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 // 替換html標簽中的非法屬性 if (count($attribs) > 0) { $str = preg_replace("/<(\/?[^><]+?)([^A-Za-z<>\-])(.*?)(".implode('|', $attribs).")(.*?)([\s><])([><]*)/i", '<$1 $3$5$6$7', $str, -1, $count); } } while ($count); return $str; } // -------------------------------------------------------------------- /** * Sanitize Naughty HTML * 消除有害的html * Callback function for xss_clean() to remove naughty HTML elements * * @param array * @return string */ protected function _sanitize_naughty_html($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 $str; } // -------------------------------------------------------------------- /** * JS Link Removal * js鏈接清理 * Callback function for xss_clean() to sanitize links * This limits the PCRE backtracks, making it more performance friendly * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in * PHP 5.2+ on link-heavy strings * 調用xss_clean 清理連接 * @param array * @return string */ protected function _js_link_removal($match) { return str_replace( $match[1], preg_replace( '#href=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|data\s*:)#si', '', $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1])) ), $match[0] ); } // -------------------------------------------------------------------- /** * JS Image Removal * js圖片清理 * Callback function for xss_clean() to sanitize image tags * This limits the PCRE backtracks, making it more performance friendly * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in * PHP 5.2+ on image tag heavy strings * * @param array * @return string */ protected function _js_img_removal($match) { return str_replace( $match[1], preg_replace( '#src=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si', '', $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1])) ), $match[0] ); } // -------------------------------------------------------------------- /** * Attribute Conversion * 屬性轉換 * Used as a callback for XSS Clean * * @param array * @return string */ protected function _convert_attribute($match) { return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]); } // -------------------------------------------------------------------- /** * Filter Attributes * 過濾屬性 * Filters tag attributes for consistency and safety * 為一致性和安全性過濾標簽屬性 * @param string * @return string */ protected function _filter_attributes($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 $out; } // -------------------------------------------------------------------- /** * HTML Entity Decode Callback * html實體解碼 * Used as a callback for XSS Clean * * @param array * @return string */ protected function _decode_entity($match) { return $this->entity_decode($match[0], strtoupper(config_item('charset'))); } // -------------------------------------------------------------------- /** * Validate URL entities * 驗證URL字符實體 * Called by xss_clean() * * @param string * @return string */ protected function _validate_entities($str) { /* * Protect GET variables in URLs * 保護url中的GET變量 */ // 901119URL5918AMP18930PROTECT8198 $str = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-]+)|i', $this->xss_hash()."\\1=\\2", $str); /* * Validate standard character entities * 驗證標准字符實體 * * Add a semicolon if missing. We do this to enable * the conversion of entities to ASCII later. * 如果沒有的話，添加一個分號。這樣做是為了以後允許字符實體到ASCII的轉換 * */ $str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str); /* * Validate UTF16 two byte encoding (x00) * 驗證UTF16兩個字節的編碼（x00） * Just as above, adds a semicolon if missing. * 像上面一樣如果不存在添加一個分號。 */ $str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str); /* * Un-Protect GET variables in URLs * URL中不保護的GET變量 */ $str = str_replace($this->xss_hash(), '&', $str); return $str; } // ---------------------------------------------------------------------- /** * Do Never Allowed * 移除不允許的字符 * A utility function for xss_clean() * * @param string * @return string */ protected function _do_never_allowed($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 $str; } // -------------------------------------------------------------------- /** * Set Cross Site Request Forgery Protection Cookie * 設置跨站請求保護Cookie * @return string */ protected function _csrf_set_hash() { if ($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 // 如果Cookie存在，我們將使用原先的值 // 我們不是必須要在每各加載的頁面都要更新它，因為當一個頁面可能要包含嵌入的子頁面時， // 嵌入的子頁面會造成這個特性的失敗 if (isset($_COOKIE[$this->_csrf_cookie_name]) && preg_match('#^[0-9a-f]{32}$#iS', $_COOKIE[$this->_csrf_cookie_name]) === 1) { www.2cto.com return $this->_csrf_hash = $_COOKIE[$this->_csrf_cookie_name]; } return $this->_csrf_hash = md5(uniqid(rand(), TRUE)); } return $this->_csrf_hash; } } /* End of file Security.php */ /* Location: ./system/libraries/Security.php */
