CI框架源码阅览-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]',		'<!--'				=> '<!--',		'-->'				=> '-->',		'<![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	 *	 * @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);		$str = preg_replace_callback("/<\w+.*?(?=>|<|$)/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: ja		vascript		 * 这用来防止字符串类似于ja		vascript		 * 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 $str;	}	// --------------------------------	/**	 * Random Hash for protecting URLs	 * 随即生成一个_xss_hssh	 * @return	string	 */	public function xss_hash()	{		if ($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('~&#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, '', $str));	}	// ----------------------------	/**	 * Compact Exploded Words	 * 压缩搜索到得单词	 * Callback function for xss_clean() to remove whitespace from	 * things like j a v a s c r i p t	 * 回调函数，用于xss_clean()，从类似于 j a v a s c r i p t中移除空格     * 	 *	 * @param	type	 * @return	type	 */	protected function _compact_exploded_words($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 |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 $str;	}	// --------------------------------	/**	 * Sanitize Naughty HTML	 * 消除有害的html	 * Callback function for xss_clean() to remove naughty HTML elements	 *	 * @param	array	 * @return	string	 */	protected function _sanitize_naughty_html($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 $str;	}	// --------------------------------	/**	 * JS Link Removal	 * js链接清理	 * Callback function for xss_clean() to sanitize links	 * This limits the PCRE backtracks, making it more performance friendly	 * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in	 * PHP 5.2+ on link-heavy strings	 * 调用xss_clean 清理连接	 * @param	array	 * @return	string	 */	protected function _js_link_removal($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|<xss|base64\s*,)#si',				'',				$this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]))			),			$match[0]		);	}	// --------------------------------	/**	 * Attribute Conversion	 * 属性转换	 * Used as a callback for XSS Clean	 *	 * @param	array	 * @return	string	 */	protected function _convert_attribute($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 */