Heim >Backend-Entwicklung >PHP-Tutorial > CI框架源码阅览-Security.php
CI框架源码阅读---------Security.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 * 本类包含一些方法,能帮助您创建安全的应用程序,对输入的数据进行安全方面的处理。 * CI官方手册本类的地址: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 * 为保护URL(跨站脚本攻击)的随机hash值 * @var string * @access protected */ protected $_xss_hash = ''; /** * Random Hash for Cross Site Request Forgery Protection Cookie * 防止跨站请求伪造cookie的随机hash * @var string * @access protected */ protected $_csrf_hash = ''; /** * Expiration time for Cross Site Request Forgery Protection Cookie * Defaults to two hours (in seconds) * 跨站请求保护Cookie的过期时间,默认是2小时(单位秒) * @var int * @access protected */ protected $_csrf_expire = 7200; /** * Token name for Cross Site Request Forgery 伪造 Protection Cookie * 跨站请求伪造保护的Cookie令牌名 * @var string * @access protected */ protected $_csrf_token_name = 'ci_csrf_token'; /** * Cookie name for Cross Site Request Forgery Protection Cookie * 跨站请求伪造保护的Cookie的Cookie名 * @var string * @access protected */ protected $_csrf_cookie_name = 'ci_csrf_token'; /** * List of never allowed strings * 决不允许的字符串的列表 * @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]', '<!--' => '<!--', '-->' => '-->', ' '' => '<comment>' ); /* never allowed, regex replacement */ /** * List of never allowed regex replacement * 不允许的正则替换字符串列表 * @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 是否开启 if (config_item('csrf_protection') === TRUE) { // CSRF config 读取CSRF 配置并赋值给本类下的对应的属性 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 // 添加应用指定的cookie前缀 if (config_item('cookie_prefix')) { $this->_csrf_cookie_name = config_item('cookie_prefix').$this->_csrf_cookie_name; } // Set the CSRF hash // 设置CSRF hash $this->_csrf_set_hash(); } log_message('debug', "Security Class Initialized"); } // -------------------------------- /** * Verify Cross Site Request Forgery Protection * 验证跨站请求伪造保护 * @return object */ public function csrf_verify() { // If it's not a POST request we will set the CSRF cookie // 如果不是post请求我们要设置 CSRF cookie if (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST') { return $this->csrf_set_cookie(); } // Do the tokens exist in both the _POST and _COOKIE arrays? // 如果请求令牌不存在,调用csrf_show_error 报错 if ( ! isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name])) { $this->csrf_show_error(); } // Do the tokens match? // 如果令牌不对,报错。 if ($_POST[$this->_csrf_token_name] != $_COOKIE[$this->_csrf_cookie_name]) { $this->csrf_show_error(); } // We kill this since we're done and we don't want to // polute the _POST array // 销毁领牌子,因为我们不想污染_POST 数组 unset($_POST[$this->_csrf_token_name]); // Nothing should last forever // 销毁cookie名 并重新设置hash和cookie unset($_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 * 设置伪造cookie保护跨站请求 * @return object */ public function csrf_set_cookie() { $expire = time() + $this->_csrf_expire; $secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0; // 当存在https时设置cookie if ($secure_cookie && (empty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) === 'off')) { return FALSE; } // 设置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 * 显示CSRF错误 * @return void */ public function csrf_show_error() { show_error('The action you have requested is not allowed.'); } // -------------------------------- /** * Get CSRF Hash * 获取CSRF hash * Getter Method * * @return string self::_csrf_hash */ public function get_csrf_hash() { return $this->_csrf_hash; } // -------------------------------- /** * Get CSRF Token Name * 获取CSRF 令排名 * Getter Method * * @return string self::csrf_token_name */ public function get_csrf_token_name() { return $this->_csrf_token_name; } // -------------------------------- /** * XSS Clean * * Sanitizes 清理 data so that Cross Site Scripting Hacks can be * prevented.阻止 This function does a fair amount of work but * it is extremely thorough, designed to prevent even the * most obscure XSS attempts 企图. Nothing is ever 100% foolproof, * of course, but I haven't been able to get anything passed * the filter. * 对数据进行过滤,从而可以防止跨站脚本攻击。这个函数做了一些工作,但是它是非常彻底的, * 甚至可以防止大多数模糊的XSS企图。当然,没有什么是100%安全的, * 但是我们在这个过滤器中已经做了所欲我们所能做想到的了。 * * Note: This function should only be used to deal with data * upon submission. It's not something that should * be used for general runtime processing. * 注意:这个函数只能用来处理已经提交的数据。 * 在通常的运行过程中,不应该使用该函数。 * * This function was based in part on some code and ideas I * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention * * To help develop this script I used this great list of * vulnerabilities along with a few other hacks I've * harvested from examining vulnerabilities in other programs: * http://ha.ckers.org/xss.html * * @param mixed string or array * @param bool * @return string */ public function xss_clean($str, $is_image = FALSE) { /* * Is the string an array? * 需要过滤的字符串是数组吗? * */ if (is_array($str)) { while (list($key) = each($str)) { $str[$key] = $this->xss_clean($str[$key]); } return $str; } /* * Remove Invisible Characters * 移除不可见字符 */ $str = remove_invisible_characters($str); // Validate Entities in URLs // 验证在URL中的字符实体 $str = $this->_validate_entities($str); /* * URL Decode * URL解码 * Just in case stuff like this is submitted: * 防止下面这样的东西提交 * <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() 不会把加号('+')解码为空格,而 urldecode() 可以。 * */ $str = rawurldecode($str); /* * Convert character entities to ASCII * 把实体字符转换成ASCII码 * 这使得我们下面的测试是可靠的,我们仅仅转换实体内的标签,因为这些是会造成安全问题的实体 * 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); $str = preg_replace_callback("/|_do_never_allowed($str); /* * Makes PHP tags safe * 使PHP标签安全 * Note: XML tags are inadvertently replaced too: * 注意: XML标签也会被无意的替换 * <?xml * * But it doesn't seem to pose a problem. * 但是它似乎不会构成问题 */ 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 * 压缩所有分解了的单词 * 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); $i ]*?)(>|$)#si", array($this, '_js_link_removal'), $str); } if (preg_match("/<img preg_replace_callback alt=" CI框架源码阅览-Security.php " >]*?)(\s?/?>|$)#si", array($this, '_js_img_removal'), $str); } if (preg_match("/script/i", $str) OR preg_match("/xss/i", $str)) { $str = preg_replace("##si", '[removed]', $str); } } while($original != $str); unset($original); // Remove evil attributes such as style, onclick and xmlns // 移除有害的属性,比如style , onclick , xmlns $str = $this->_remove_evil_attributes($str, $is_image); /* * Sanitize naughty HTML elements * 清理不适当的HTML元素 * If a tag containing any of the words in the list * below is found, the tag gets converted to entities. * 如果一个标签包含任何一个下面列表中的单词,这个标签转换为一个字符实体 * 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'; $str = preg_replace_callback('#_do_never_allowed($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 $str; } // -------------------------------- /** * Random Hash for protecting URLs * 随即生成一个_xss_hssh * @return string */ public function xss_hash() { if ($this->_xss_hash == '') { mt_srand(); $this->_xss_hash = md5(time() + mt_rand(0, 1999999999)); } return $this->_xss_hash; } // -------------------------------- /** * HTML Entities Decode * HTML 实体解码 * This function is a replacement for html_entity_decode() * 这个函数用来替换 html_entity_decode()函数 * The reason we are not using html_entity_decode() by itself is because * while it is not technically技术上 correct to leave out the semicolon * at the end of an entity most browsers will still interpret the entity * correctly. html_entity_decode() does not convert entities without * semicolons, so we are left with our own little solution here. Bummer. * 当编码字符后没有写;时,大部分浏览器都能够正确的解释代码,但是,html_entity_decode将不会解释它 * html_entity_decode()不会转换没有分号的实体,所以使用自己的解决方案 * @param string * @param string * @return string */ public function entity_decode($str, $charset='UTF-8') { if (stristr($str, '&') === FALSE) { return $str; } $str = html_entity_decode($str, ENT_COMPAT, $charset); $str = preg_replace('~(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", // "%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, '', $str)); } // ---------------------------- /** * Compact Exploded Words * 压缩搜索到得单词 * Callback function for xss_clean() to remove whitespace from * things like j a v a s c r i p t * 回调函数,用于xss_clean(),从类似于 j a v a s c r i p t中移除空格 * * * @param type * @return type */ protected function _compact_exploded_words($matches) { return preg_replace('/\s+/s', '', $matches[1]).$matches[2]; } // -------------------------------- /* * Remove Evil HTML Attributes (like evenhandlers and style) * 移除有害的html属性,(像事件处理和样式) * It removes the evil attribute and either: * - Everything up until a space * For example, everything between the pipes: * <a class="link"> * - Everything inside the quotes * For example, everything between the pipes: * </a><a alert 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事件处理器 $evil_attributes = array('on\w*', 'style', 'xmlns', 'formaction'); if ($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图片中放入了XML元数据 * 包含命名空间,所以我们必须对图片允许这些 */ unset($evil_attributes[array_search('xmlns', $evil_attributes)]); } do { $count = 0; $attribs = array(); // find occurrences of illegal attribute strings without quotes // 找出没有加引号的的不合法的属性 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) // 找出没有引号的不合法属性(042,4,0是八进制引号) 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 // 替换html标签中的非法属性 if (count($attribs) > 0) { $str = preg_replace("/\-])(.*?)(".implode('|', $attribs).")(.*?)([\s>', '', '_filter_attributes(str_replace(array(''), '', $match[1])) ), $match[0] ); } // -------------------------------- /** * JS Image Removal * js图片清理 * Callback function for xss_clean() to sanitize image tags * This limits the PCRE backtracks, making it more performance friendly * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in * PHP 5.2+ on image tag heavy strings * * @param array * @return string */ protected function _js_img_removal($match) { return str_replace( $match[1], preg_replace( '#src=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script>_filter_attributes(str_replace(array('<', '>'), '', $match[1])) ), $match[0] ); } // -------------------------------- /** * Attribute Conversion * 属性转换 * Used as a callback for XSS Clean * * @param array * @return string */ protected function _convert_attribute($match) { return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]); } // -------------------------------- /** * Filter Attributes * 过滤属性 * Filters tag attributes for consistency and safety * 为一致性和安全性过滤标签属性 * @param string * @return string */ protected function _filter_attributes($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 $out; } // -------------------------------- /** * HTML Entity Decode Callback * html实体解码 * Used as a callback for XSS Clean * * @param array * @return string */ protected function _decode_entity($match) { return $this->entity_decode($match[0], strtoupper(config_item('charset'))); } // -------------------------------- /** * Validate URL entities * 验证URL字符实体 * Called by xss_clean() * * @param string * @return string */ protected function _validate_entities($str) { /* * Protect GET variables in URLs * 保护url中的GET变量 */ // 901119URL5918AMP18930PROTECT8198 $str = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-]+)|i', $this->xss_hash()."\\1=\\2", $str); /* * Validate standard character entities * 验证标准字符实体 * * Add a semicolon if missing. We do this to enable * the conversion of entities to ASCII later. * 如果没有的话,添加一个分号。这样做是为了以后允许字符实体到ASCII的转换 * */ $str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str); /* * Validate UTF16 two byte encoding (x00) * 验证UTF16两个字节的编码(x00) * Just as above, adds a semicolon if missing. * 像上面一样如果不存在添加一个分号。 */ $str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str); /* * Un-Protect GET variables in URLs * URL中不保护的GET变量 */ $str = str_replace($this->xss_hash(), '&', $str); return $str; } // ---------------------------------- /** * Do Never Allowed * 移除不允许的字符 * A utility function for xss_clean() * * @param string * @return string */ protected function _do_never_allowed($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 $str; } // -------------------------------- /** * Set Cross Site Request Forgery Protection Cookie * 设置跨站请求保护Cookie * @return string */ protected function _csrf_set_hash() { if ($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,我们将使用原先的值 // 我们不是必须要在每各加载的页面都要更新它,因为当一个页面可能要包含嵌入的子页面时, // 嵌入的子页面会造成这个特性的失败 if (isset($_COOKIE[$this->_csrf_cookie_name]) && preg_match('#^[0-9a-f]{32}$#iS', $_COOKIE[$this->_csrf_cookie_name]) === 1) { 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 */ </script></a></blink></blink></comment>