CI框架安全类Security.php源码分析
发布:smiling 来源: PHP粉丝网 添加日期:2021-04-23 10:13:05 浏览: 评论:0
之前我们分析了CI框架的session类session.php,本文我们继续分析CI框架的安全类security.php文件,方便我们更详细的了解CI框架,从而更熟练的应用CI框架
CI安全类提供了全局防御CSRF攻击和XSS攻击策略,只需要在配置文件开启即可:
$config['csrf_protection'] = TRUE;
$config['global_xss_filtering'] = TRUE;
并提供了实用方法:
$this->security->xss_clean($data);//第二个参数为TRUE,验证图片安全
$this->security->sanitize_filename()//过滤文件名
CI也提供了安全函数:
xss_clean()//xss过滤
sanitize_filename()//净化文件名
do_hash()//md5或sha加密
strip_image_tags() //删除图片标签的不必要字符
encode_php_tags()//把PHP脚本标签强制转成实体对象
代码如下:
- <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
- /**
- * 安全类
- */
- class CI_Security {
- //url的随机hash值
- protected $_xss_hash = '';
- //防csrf攻击的cookie标记的哈希值
- protected $_csrf_hash = '';
- //防csrf cookie过期时间
- protected $_csrf_expire = 7200;
- //防csrf的cookie名称
- protected $_csrf_token_name = 'ci_csrf_token';
- //防csrf的token名称
- protected $_csrf_cookie_name = 'ci_csrf_token';
- //不允许出现的字符串数组
- 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>'
- );
- //不允许出现的正则表达式数组
- 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?"
- );
- //构造函数
- public function __construct()
- {
- // CSRF保护是否开启
- if (config_item('csrf_protection') === TRUE)
- {
- // CSRF配置
- foreach (array('csrf_expire', 'csrf_token_name', 'csrf_cookie_name') as $key)
- {
- if (FALSE !== ($val = config_item($key)))
- {
- $this->{'_'.$key} = $val;
- }
- }
- // _csrf_cookie_name加上cookie前缀
- if (config_item('cookie_prefix'))
- {
- $this->_csrf_cookie_name = config_item('cookie_prefix').$this->_csrf_cookie_name;
- }
- // 设置csrf的hash值
- $this->_csrf_set_hash();
- }
- log_message('debug', "Security Class Initialized");
- }
- // --------------------------------------------------------------------
- /**
- * Verify Cross Site Request Forgery Protection
- *
- * @return object
- */
- public function csrf_verify()
- {
- // 如果不是post请求,则设置csrf的cookie值
- if (strtoupper($_SERVER['REQUEST_METHOD']) !== 'POST')
- {
- return $this->csrf_set_cookie();
- }
- // Do the tokens exist in both the _POST and _COOKIE arrays?
- if ( ! isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]))
- {
- $this->csrf_show_error();
- }
- // token匹配吗
- if ($_POST[$this->_csrf_token_name] != $_COOKIE[$this->_csrf_cookie_name])
- {
- $this->csrf_show_error();
- }
- // We kill this since we're done and we don't want to
- // polute the _POST array
- unset($_POST[$this->_csrf_token_name]);
- // Nothing should last forever
- unset($_COOKIE[$this->_csrf_cookie_name]);
- $this->_csrf_set_hash();
- $this->csrf_set_cookie();
- log_message('debug', 'CSRF token verified');
- return $this;
- }
- // --------------------------------------------------------------------
- /**
- * 设置csrf的cookie值
- */
- public function csrf_set_cookie()
- {
- $expire = time() + $this->_csrf_expire;
- $secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0;
- if ($secure_cookie && (emptyempty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) === 'off'))
- {
- return FALSE;
- }
- 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;
- }
- //csrf保存
- public function csrf_show_error()
- {
- show_error('The action you have requested is not allowed.');
- }
- //获取csrf的hash值
- public function get_csrf_hash()
- {
- return $this->_csrf_hash;
- }
- //获取csrf的token值
- public function get_csrf_token_name()
- {
- return $this->_csrf_token_name;
- }
- /**
- * XSS 过滤
- */
- public function xss_clean($str, $is_image = FALSE)
- {
- //是否是数组
- if (is_array($str))
- {
- while (list($key) = each($str))
- {
- $str[$key] = $this->xss_clean($str[$key]);
- }
- return $str;
- }
- //去掉可见字符串
- $str = remove_invisible_characters($str);
- // 验证实体url
- $str = $this->_validate_entities($str);
- /*
- * URL 解码
- *
- * Just in case stuff like this is submitted:
- *
- * <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
- *
- */
- $str = rawurldecode($str);
- /*
- * Convert character entities to ASCII
- *
- * 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!
- */
- $str = remove_invisible_characters($str);
- /*
- * Convert all tabs to spaces
- *
- * This prevents strings like this: ja vascript
- * NOTE: we deal with spaces between characters later.
- * NOTE: preg_replace was found to be amazingly slow here on
- * large blocks of data, so we use str_replace.
- */
- if (strpos($str, "\t") !== FALSE)
- {
- $str = str_replace("\t", ' ', $str);
- }
- /*
- * Capture converted string for later comparison
- */
- $converted_string = $str;
- // Remove Strings that are never allowed
- $str = $this->_do_never_allowed($str);
- /*
- * Makes PHP tags safe
- *
- * Note: XML tags are inadvertently replaced too:
- *
- * <?xml
- *
- * But it doesn't seem to pose a problem.
- */
- 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
- *
- * 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
- * We used to do some version comparisons and use of stripos for PHP5,
- * but it is dog slow compared to these simplified non-capturing
- * 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
- $str = $this->_remove_evil_attributes($str, $is_image);
- /*
- * Sanitize naughty HTML elements
- *
- * If a tag containing any of the words in the list
- * below is found, the tag gets converted to entities.
- *
- * 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
- *
- * 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.
- *
- * 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
- // This adds a bit of extra precaution in case
- // something got through the above filters
- $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 $str;
- }
- // --------------------------------------------------------------------
- //保护url的随机hash值
- public function xss_hash()
- {
- if ($this->_xss_hash == '')
- {
- mt_srand();
- $this->_xss_hash = md5(time() + mt_rand(0, 1999999999));
- }
- return $this->_xss_hash;
- }
- // --------------------------------------------------------------------
- /**
- * html实体转码
- */
- public function entity_decode($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)', $str);
- }
- // --------------------------------------------------------------------
- //过滤文件名,保证文件名安全
- public function sanitize_filename($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, '', $str));
- }
- //压缩单词如j a v a s c r i p t成javascript
- protected function _compact_exploded_words($matches)
- {
- return preg_replace('/\s+/s', '', $matches[1]).$matches[2];
- }
- // --------------------------------------------------------------------
- /*
- * 去掉一些危害的html属性
- */
- protected function _remove_evil_attributes($str, $is_image)
- {
- // All javascript event handlers (e.g. onload, onclick, onmouseover), style, and xmlns
- $evil_attributes = array('on\w*', 'style', 'xmlns', 'formaction');
- if ($is_image === TRUE)
- {
- /*
- * Adobe Photoshop puts XML metadata into JFIF images,
- * including namespacing, so we have to allow this for images.
- */
- unset($evil_attributes[array_search('xmlns', $evil_attributes)]);
- }
- do {
- $count = 0;
- $attribs = array();
- // find occurrences of illegal attribute strings with quotes (042 and 047 are octal quotes)
- 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], '/');
- }
- // find occurrences of illegal attribute strings without quotes
- preg_match_all('/('.implode('|', $evil_attributes).')\s*=\s*([^\s>]*)/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
- if (count($attribs) > 0)
- {
- $str = preg_replace('/(<?)(\/?[^><]+?)([^A-Za-z<>\-])(.*?)('.implode('|', $attribs).')(.*?)([\s><]?)([><]*)/i', '$1$2 $4$6$7$8', $str, -1, $count);
- }
- } while ($count);
- return $str;
- }
- // --------------------------------------------------------------------
- /**
- * 净化html,补齐未关闭的标签
- */
- protected function _sanitize_naughty_html($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 $str;
- }
- // --------------------------------------------------------------------
- /**
- * 过滤超链接中js
- */
- protected function _js_link_removal($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]))
- ),
- $match[0]
- );
- }
- // --------------------------------------------------------------------
- /**
- * 过滤图片链接中的js
- */
- protected function _js_img_removal($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]))
- ),
- $match[0]
- );
- }
- // --------------------------------------------------------------------
- /**
- * 转换属性,将一些字符转换成实体
- */
- protected function _convert_attribute($match)
- {
- return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);
- }
- // --------------------------------------------------------------------
- //过滤html标签属性
- protected function _filter_attributes($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 $out;
- }
- // --------------------------------------------------------------------
- //html实体转码
- protected function _decode_entity($match)
- {
- return $this->entity_decode($match[0], strtoupper(config_item('charset')));
- }
- // --------------------------------------------------------------------
- /**
- * 验证url实体
- */
- protected function _validate_entities($str)
- {
- /*
- * Protect GET variables in URLs
- */
- // 901119URL5918AMP18930PROTECT8198
- $str = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-]+)|i', $this->xss_hash()."\\1=\\2", $str);
- /*
- * Validate standard character entities
- *
- * Add a semicolon if missing. We do this to enable
- * the conversion of entities to ASCII later.
- *
- */
- $str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str);
- /*
- * Validate UTF16 two byte encoding (x00)
- *
- * Just as above, adds a semicolon if missing.
- *
- */
- $str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str);
- /*
- * Un-Protect GET variables in URLs
- */
- $str = str_replace($this->xss_hash(), '&', $str);
- return $str;
- }
- // ----------------------------------------------------------------------
- //过滤不允许出现的字符串
- protected function _do_never_allowed($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 $str;
- }
- // --------------------------------------------------------------------
- //设置csrf的hash值
- protected function _csrf_set_hash()
- {
- if ($this->_csrf_hash == '')
- {
- // 如果_csrf_cookie_name存在,直接作为csrf hash值
- 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];
- }//www.phpfensi.com
- //否则随机一个md5字符串
- return $this->_csrf_hash = md5(uniqid(rand(), TRUE));
- }
- return $this->_csrf_hash;
- }
- }
Tags: CI框架安全类 Security php
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