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 * * @packageCodeIgniter * @authorExpressionEngine Dev Team * @copyrightCopyright (c) 2008 - 2011, EllisLab, Inc. * @licensehttp://codeigniter.com/user_guide/license.html * @linkhttp://codeigniter.com * @sinceVersion 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 * @packageCodeIgniter * @subpackageLibraries * @categorySecurity * @authorExpressionEngine Dev Team * @linkhttp://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]','<!--'=> '<!--','-->'=> '-->','<![CDATA['=> '<![CDATA[','<comment>'=> '<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 * * @returnvoid */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 * @returnobject */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 cookieif (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[$this->_csrf_token_name]);// Nothing should last forever// 销毁cookie名 并重新设置hash和cookieunset($_COOKIE[$this->_csrf_cookie_name]);$this->_csrf_set_hash();$this->csrf_set_cookie();log_message('debug', 'CSRF token verified');return $this;}// --------------------------------/** * Set Cross Site Request Forgery Protection Cookie * 设置伪造cookie保护跨站请求 * @returnobject */public function csrf_set_cookie(){$expire = time() + $this->_csrf_expire;$secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0;// 当存在https时设置cookieif ($secure_cookie && (empty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) === 'off')){return FALSE;}// 设置cookiesetcookie($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 * @returnvoid */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 $this->_csrf_token_name;}// --------------------------------/** * XSS Clean * * Sanitizes 清理 data so that Cross Site Scripting Hacks can be * prevented.阻止 This function does a fair amount of work but * it is extremely thorough, designed to prevent even the * most obscure XSS attempts 企图. Nothing is ever 100% foolproof, * of course, but I haven't been able to get anything passed * the filter. * 对数据进行过滤，从而可以防止跨站脚本攻击。这个函数做了一些工作，但是它是非常彻底的， * 甚至可以防止大多数模糊的XSS企图。当然，没有什么是100%安全的， * 但是我们在这个过滤器中已经做了所欲我们所能做想到的了。 * * Note: This function should only be used to deal with data * upon submission. It's not something that should * be used for general runtime processing. * 注意：这个函数只能用来处理已经提交的数据。 * 在通常的运行过程中，不应该使用该函数。 * * This function was based in part on some code and ideas I * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention * * To help develop this script I used this great list of * vulnerabilities along with a few other hacks I've * harvested from examining vulnerabilities in other programs: * http://ha.ckers.org/xss.html * * @parammixedstring or array * @param bool * @returnstring */public function xss_clean($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("/<\w+.*?(?=>|<|$)/si", array($this, '_decode_entity'), $str);/* * Remove Invisible Characters Again! * 再次删除不可见字符 */$str = remove_invisible_characters($str);/* * Convert all tabs to spaces * 转换所有制表符为空格 * This prevents strings like this: javascript * 这用来防止字符串类似于javascript * NOTE: we deal with spaces between characters later. * 注意： 我们将在后面处理字符之间的空格 * NOTE: preg_replace was found to be amazingly slow here on * large blocks of data, so we use str_replace. * 注意：preg_replace在这里是极其缓慢的对于大块的数据，所以使用str_replace * */if (strpos($str, "\t") !== FALSE){$str = str_replace("\t", ' ', $str);}/* * Capture 捕获 converted string for later comparison * 为以后的比较捕获转换的字符串 */$converted_string = $str;// Remove Strings that are never allowed// 删除绝不容许的字符串$str = $this->_do_never_allowed($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 < $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'), $str);}/* * Remove disallowed Javascript in links or img tags * 移除在链接和图片标签中不允许的javascript代码 * We used to do some version comparisons and use of stripos for PHP5, * 我们通常在PHP5中使用stripos做一些版本的比较， * but it is dog slow compared to these simplified non-capturing * 但是特别是当模式在字符串中存在的时候，它要比非捕获的preg_match()慢很多 * preg_match(), especially if the pattern exists in the string */do{$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';$str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);/* * Sanitize naughty scripting elements * 清理不合法的脚本元素 * Similar to above, only instead of looking for * tags it looks for PHP and JavaScript commands * that are disallowed. Rather than removing the * code, it simply converts the parenthesis to entities * rendering the code un-executable. * 上面的类似，仅仅替换查询到的类似于PHP和Javascript命令的不被允许的标签 * 胜过移除这些代码，转换这些代码为不可执行的实体更好 * * For example:eval('some code') * Becomes:eval('some code') */$str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2(\\3)", $str);// Final clean up// 最后的清理// This adds a bit of extra precaution in case// something got through the above filters// 额外预防，防止上面的处理产生不合法的字符$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 $str;}// --------------------------------/** * Random Hash for protecting URLs * 随即生成一个_xss_hssh * @returnstring */public function xss_hash(){if ($this->_xss_hash == ''){mt_srand();$this->_xss_hash = md5(time() + mt_rand(0, 1999999999));}return $this->_xss_hash;}// --------------------------------/** * HTML Entities Decode * HTML 实体解码 * This function is a replacement for html_entity_decode() * 这个函数用来替换 html_entity_decode()函数 * The reason we are not using html_entity_decode() by itself is because * while it is not technically技术上 correct to leave out the semicolon * at the end of an entity most browsers will still interpret the entity * correctly. html_entity_decode() does not convert entities without * semicolons, so we are left with our own little solution here. Bummer. * 当编码字符后没有写；时，大部分浏览器都能够正确的解释代码，但是，html_entity_decode将不会解释它 * html_entity_decode()不会转换没有分号的实体，所以使用自己的解决方案 * @paramstring * @paramstring * @returnstring */public function entity_decode($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)', $str);}// --------------------------------/** * Filename Security * 文件名安全 * @paramstring * @param bool * @returnstring */public function sanitize_filename($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, '', $str));}// ----------------------------/** * Compact Exploded Words * 压缩搜索到得单词 * Callback function for xss_clean() to remove whitespace from * things like j a v a s c r i p t * 回调函数，用于xss_clean()，从类似于 j a v a s c r i p t中移除空格 * * * @paramtype * @returntype */protected function _compact_exploded_words($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 |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("/<(\/?[^><]+?)([^A-Za-z<>\-])(.*?)(".implode('|', $attribs).")(.*?)([\s><])([><]*)/i", '<$1 $3$5$6$7', $str, -1, $count);}} while ($count);return $str;}// --------------------------------/** * Sanitize Naughty HTML * 消除有害的html * Callback function for xss_clean() to remove naughty HTML elements * * @paramarray * @returnstring */protected function _sanitize_naughty_html($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 $str;}// --------------------------------/** * JS Link Removal * js链接清理 * Callback function for xss_clean() to sanitize links * This limits the PCRE backtracks, making it more performance friendly * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in * PHP 5.2+ on link-heavy strings * 调用xss_clean 清理连接 * @paramarray * @returnstring */protected function _js_link_removal($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 * * @paramarray * @returnstring */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 * 属性转换 * Used as a callback for XSS Clean * * @paramarray * @returnstring */protected function _convert_attribute($match){return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);}// --------------------------------/** * Filter Attributes * 过滤属性 * Filters tag attributes for consistency and safety * 为一致性和安全性过滤标签属性 * @paramstring * @returnstring */protected function _filter_attributes($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 $out;}// --------------------------------/** * HTML Entity Decode Callback * html实体解码 * Used as a callback for XSS Clean * * @paramarray * @returnstring */protected function _decode_entity($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 $str;}// --------------------------------/** * Set Cross Site Request Forgery Protection Cookie * 设置跨站请求保护Cookie * @returnstring */protected function _csrf_set_hash(){if ($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 */