CI框架源码阅读---------Security.php

[php]

/**

* 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]',

'' => '-->',

' '

'' => ''

);

/* 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 ($secure_cookie && (emptyempty($_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

* Google

*

* 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("/|

/*

* 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

*

*

* 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('/

}

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

{

$temp .= substr($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("/

{

$str = preg_replace_callback("#]*?)(>|$)#si", array($this, '_js_link_removal'), $str);

}

if (preg_match("/

{

$str = preg_replace_callback("#]*?)(\s?/?>|$)#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:

* Becomes:

*/

$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('#

/*

* 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('~(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:

*

* - Everything inside the quotes

* For example, everything between the pipes:

*

*

* @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>

}

} 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 = '

// encode captured opening or closing brace to prevent recursive vectors

$str .= str_replace(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|

$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|

$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('>', '', '

}

// --------------------------------------------------------------------

/**

* 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)

{ 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 */