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authorFlorian Pritz <bluewind@xinu.at>2017-09-09 16:05:22 +0200
committerFlorian Pritz <bluewind@xinu.at>2017-09-09 16:05:22 +0200
commit27639d64d06b62f237bbde253c46cd28fdce8884 (patch)
tree7a2f00cfd44cfcdfe6cb1abc1cfc0675632948c4 /system/core/Security.php
parent9c5bfbee5b42ea50a5611c537b8dbf01d7a64f79 (diff)
parent6c7a4266410070d30f8f6bcdf9c9e67f3d6478e3 (diff)
Merge tag '3.1.5' into dev-ci3
Signed-off-by: Florian Pritz <bluewind@xinu.at>
Diffstat (limited to 'system/core/Security.php')
-rw-r--r--system/core/Security.php915
1 files changed, 560 insertions, 355 deletions
diff --git a/system/core/Security.php b/system/core/Security.php
index efa2df922..082ffa96b 100644
--- a/system/core/Security.php
+++ b/system/core/Security.php
@@ -1,19 +1,41 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
/**
* CodeIgniter
*
- * An open source application development framework for PHP 5.1.6 or newer
+ * An open source application development framework for PHP
*
- * @package CodeIgniter
- * @author ExpressionEngine Dev Team
- * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc.
- * @license http://codeigniter.com/user_guide/license.html
- * @link http://codeigniter.com
- * @since Version 1.0
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package CodeIgniter
+ * @author EllisLab Dev Team
+ * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license http://opensource.org/licenses/MIT MIT License
+ * @link https://codeigniter.com
+ * @since Version 1.0.0
* @filesource
*/
-
-// ------------------------------------------------------------------------
+defined('BASEPATH') OR exit('No direct script access allowed');
/**
* Security Class
@@ -21,119 +43,165 @@
* @package CodeIgniter
* @subpackage Libraries
* @category Security
- * @author ExpressionEngine Dev Team
- * @link http://codeigniter.com/user_guide/libraries/security.html
+ * @author EllisLab Dev Team
+ * @link https://codeigniter.com/user_guide/libraries/security.html
*/
class CI_Security {
/**
- * Random Hash for protecting URLs
+ * List of sanitize filename strings
*
- * @var string
- * @access protected
+ * @var array
*/
- protected $_xss_hash = '';
+ public $filename_bad_chars = array(
+ '../', '<!--', '-->', '<', '>',
+ "'", '"', '&', '$', '#',
+ '{', '}', '[', ']', '=',
+ ';', '?', '%20', '%22',
+ '%3c', // <
+ '%253c', // <
+ '%3e', // >
+ '%0e', // >
+ '%28', // (
+ '%29', // )
+ '%2528', // (
+ '%26', // &
+ '%24', // $
+ '%3f', // ?
+ '%3b', // ;
+ '%3d' // =
+ );
+
/**
- * Random Hash for Cross Site Request Forgery Protection Cookie
+ * Character set
+ *
+ * Will be overridden by the constructor.
*
- * @var string
- * @access protected
+ * @var string
*/
- protected $_csrf_hash = '';
+ public $charset = 'UTF-8';
+
/**
- * Expiration time for Cross Site Request Forgery Protection Cookie
- * Defaults to two hours (in seconds)
+ * XSS Hash
+ *
+ * Random Hash for protecting URLs.
*
- * @var int
- * @access protected
+ * @var string
*/
- protected $_csrf_expire = 7200;
+ protected $_xss_hash;
+
/**
- * Token name for Cross Site Request Forgery Protection Cookie
+ * CSRF Hash
+ *
+ * Random hash for Cross Site Request Forgery protection cookie
*
- * @var string
- * @access protected
+ * @var string
*/
- protected $_csrf_token_name = 'ci_csrf_token';
+ protected $_csrf_hash;
+
/**
- * Cookie name for Cross Site Request Forgery Protection Cookie
+ * CSRF Expire time
+ *
+ * Expiration time for Cross Site Request Forgery protection cookie.
+ * Defaults to two hours (in seconds).
*
- * @var string
- * @access protected
+ * @var int
*/
- protected $_csrf_cookie_name = 'ci_csrf_token';
+ protected $_csrf_expire = 7200;
+
+ /**
+ * CSRF Token name
+ *
+ * Token name for Cross Site Request Forgery protection cookie.
+ *
+ * @var string
+ */
+ protected $_csrf_token_name = 'ci_csrf_token';
+
+ /**
+ * CSRF Cookie name
+ *
+ * Cookie name for Cross Site Request Forgery protection cookie.
+ *
+ * @var string
+ */
+ protected $_csrf_cookie_name = 'ci_csrf_token';
+
/**
* List of never allowed strings
*
- * @var array
- * @access protected
+ * @var array
*/
- protected $_never_allowed_str = array(
- 'document.cookie' => '[removed]',
- 'document.write' => '[removed]',
- '.parentNode' => '[removed]',
- '.innerHTML' => '[removed]',
- 'window.location' => '[removed]',
- '-moz-binding' => '[removed]',
- '<!--' => '&lt;!--',
- '-->' => '--&gt;',
- '<![CDATA[' => '&lt;![CDATA[',
- '<comment>' => '&lt;comment&gt;'
+ protected $_never_allowed_str = array(
+ 'document.cookie' => '[removed]',
+ 'document.write' => '[removed]',
+ '.parentNode' => '[removed]',
+ '.innerHTML' => '[removed]',
+ '-moz-binding' => '[removed]',
+ '<!--' => '&lt;!--',
+ '-->' => '--&gt;',
+ '<![CDATA[' => '&lt;![CDATA[',
+ '<comment>' => '&lt;comment&gt;',
+ '<%' => '&lt;&#37;'
);
- /* never allowed, regex replacement */
/**
- * List of never allowed regex replacement
+ * List of never allowed regex replacements
*
- * @var array
- * @access protected
+ * @var array
*/
protected $_never_allowed_regex = array(
'javascript\s*:',
+ '(document|(document\.)?window)\.(location|on\w*)',
'expression\s*(\(|&\#40;)', // CSS and IE
'vbscript\s*:', // IE, surprise!
- 'Redirect\s+302',
+ 'wscript\s*:', // IE
+ 'jscript\s*:', // IE
+ 'vbs\s*:', // IE
+ 'Redirect\s+30\d',
"([\"'])?data\s*:[^\\1]*?base64[^\\1]*?,[^\\1]*?\\1?"
);
/**
- * Constructor
+ * Class constructor
*
* @return void
*/
public function __construct()
{
// Is CSRF protection enabled?
- if (config_item('csrf_protection') === TRUE)
+ if (config_item('csrf_protection'))
{
// CSRF config
foreach (array('csrf_expire', 'csrf_token_name', 'csrf_cookie_name') as $key)
{
- if (FALSE !== ($val = config_item($key)))
+ if (NULL !== ($val = config_item($key)))
{
$this->{'_'.$key} = $val;
}
}
// Append application specific cookie prefix
- if (config_item('cookie_prefix'))
+ if ($cookie_prefix = config_item('cookie_prefix'))
{
- $this->_csrf_cookie_name = config_item('cookie_prefix').$this->_csrf_cookie_name;
+ $this->_csrf_cookie_name = $cookie_prefix.$this->_csrf_cookie_name;
}
// Set the CSRF hash
$this->_csrf_set_hash();
}
- log_message('debug', "Security Class Initialized");
+ $this->charset = strtoupper(config_item('charset'));
+
+ log_message('info', 'Security Class Initialized');
}
// --------------------------------------------------------------------
/**
- * Verify Cross Site Request Forgery Protection
+ * CSRF Verify
*
- * @return object
+ * @return CI_Security
*/
public function csrf_verify()
{
@@ -143,52 +211,74 @@ class CI_Security {
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]))
+ // Check if URI has been whitelisted from CSRF checks
+ if ($exclude_uris = config_item('csrf_exclude_uris'))
{
- $this->csrf_show_error();
+ $uri = load_class('URI', 'core');
+ foreach ($exclude_uris as $excluded)
+ {
+ if (preg_match('#^'.$excluded.'$#i'.(UTF8_ENABLED ? 'u' : ''), $uri->uri_string()))
+ {
+ return $this;
+ }
+ }
}
- // Do the tokens match?
- if ($_POST[$this->_csrf_token_name] != $_COOKIE[$this->_csrf_cookie_name])
- {
- $this->csrf_show_error();
- }
+ // Check CSRF token validity, but don't error on mismatch just yet - we'll want to regenerate
+ $valid = isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name])
+ && hash_equals($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]);
- // We kill this since we're done and we don't want to
- // polute the _POST array
+ // We kill this since we're done and we don't want to pollute the _POST array
unset($_POST[$this->_csrf_token_name]);
- // Nothing should last forever
- unset($_COOKIE[$this->_csrf_cookie_name]);
+ // Regenerate on every submission?
+ if (config_item('csrf_regenerate'))
+ {
+ // Nothing should last forever
+ unset($_COOKIE[$this->_csrf_cookie_name]);
+ $this->_csrf_hash = NULL;
+ }
+
$this->_csrf_set_hash();
$this->csrf_set_cookie();
- log_message('debug', 'CSRF token verified');
+ if ($valid !== TRUE)
+ {
+ $this->csrf_show_error();
+ }
+ log_message('info', 'CSRF token verified');
return $this;
}
// --------------------------------------------------------------------
/**
- * Set Cross Site Request Forgery Protection Cookie
+ * CSRF Set Cookie
*
- * @return object
+ * @codeCoverageIgnore
+ * @return CI_Security
*/
public function csrf_set_cookie()
{
$expire = time() + $this->_csrf_expire;
- $secure_cookie = (config_item('cookie_secure') === TRUE) ? 1 : 0;
+ $secure_cookie = (bool) config_item('cookie_secure');
- if ($secure_cookie && (empty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) === 'off'))
+ if ($secure_cookie && ! is_https())
{
return FALSE;
}
- setcookie($this->_csrf_cookie_name, $this->_csrf_hash, $expire, config_item('cookie_path'), config_item('cookie_domain'), $secure_cookie);
-
- log_message('debug', "CRSF cookie Set");
+ setcookie(
+ $this->_csrf_cookie_name,
+ $this->_csrf_hash,
+ $expire,
+ config_item('cookie_path'),
+ config_item('cookie_domain'),
+ $secure_cookie,
+ config_item('cookie_httponly')
+ );
+ log_message('info', 'CSRF cookie sent');
return $this;
}
@@ -202,7 +292,7 @@ class CI_Security {
*/
public function csrf_show_error()
{
- show_error('The action you have requested is not allowed.');
+ show_error('The action you have requested is not allowed.', 403);
}
// --------------------------------------------------------------------
@@ -210,9 +300,8 @@ class CI_Security {
/**
* Get CSRF Hash
*
- * Getter Method
- *
- * @return string self::_csrf_hash
+ * @see CI_Security::$_csrf_hash
+ * @return string CSRF hash
*/
public function get_csrf_hash()
{
@@ -224,9 +313,8 @@ class CI_Security {
/**
* Get CSRF Token Name
*
- * Getter Method
- *
- * @return string self::csrf_token_name
+ * @see CI_Security::$_csrf_token_name
+ * @return string CSRF token name
*/
public function get_csrf_token_name()
{
@@ -239,52 +327,44 @@ class CI_Security {
* XSS Clean
*
* Sanitizes data so that Cross Site Scripting Hacks can be
- * prevented. This function does a fair amount of work but
+ * prevented. This method does a fair amount of work but
* it is extremely thorough, designed to prevent even the
* most obscure XSS attempts. Nothing is ever 100% foolproof,
* of course, but I haven't been able to get anything passed
* the filter.
*
- * 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.
+ * Note: Should only be used to deal with data upon submission.
+ * It's not something that should be used for general
+ * runtime processing.
*
- * This function was based in part on some code and ideas I
- * got from Bitflux: http://channel.bitflux.ch/wiki/XSS_Prevention
+ * @link http://channel.bitflux.ch/wiki/XSS_Prevention
+ * Based in part on some code and ideas from Bitflux.
*
- * 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
+ * @link http://ha.ckers.org/xss.html
+ * 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.
*
- * @param mixed string or array
- * @param bool
+ * @param string|string[] $str Input data
+ * @param bool $is_image Whether the input is an image
* @return string
*/
public function xss_clean($str, $is_image = FALSE)
{
- /*
- * Is the string an array?
- *
- */
+ // Is the string an array?
if (is_array($str))
{
- while (list($key) = each($str))
+ foreach ($str as $key => &$value)
{
- $str[$key] = $this->xss_clean($str[$key]);
+ $str[$key] = $this->xss_clean($value);
}
return $str;
}
- /*
- * Remove Invisible Characters
- */
+ // Remove Invisible Characters
$str = remove_invisible_characters($str);
- // Validate Entities in URLs
- $str = $this->_validate_entities($str);
-
/*
* URL Decode
*
@@ -293,9 +373,18 @@ class CI_Security {
* <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);
+ if (stripos($str, '%') !== false)
+ {
+ do
+ {
+ $oldstr = $str;
+ $str = rawurldecode($str);
+ $str = preg_replace_callback('#%(?:\s*[0-9a-f]){2,}#i', array($this, '_urldecodespaces'), $str);
+ }
+ while ($oldstr !== $str);
+ unset($oldstr);
+ }
/*
* Convert character entities to ASCII
@@ -303,16 +392,11 @@ class CI_Security {
* 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.
- *
*/
+ $str = preg_replace_callback("/[^a-z0-9>]+[a-z0-9]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);
+ $str = preg_replace_callback('/<\w+.*/si', array($this, '_decode_entity'), $str);
- $str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);
-
- $str = preg_replace_callback("/<\w+.*?(?=>|<|$)/si", array($this, '_decode_entity'), $str);
-
- /*
- * Remove Invisible Characters Again!
- */
+ // Remove Invisible Characters Again!
$str = remove_invisible_characters($str);
/*
@@ -323,15 +407,9 @@ class CI_Security {
* NOTE: preg_replace was found to be amazingly slow here on
* large blocks of data, so we use str_replace.
*/
+ $str = str_replace("\t", ' ', $str);
- if (strpos($str, "\t") !== FALSE)
- {
- $str = str_replace("\t", ' ', $str);
- }
-
- /*
- * Capture converted string for later comparison
- */
+ // Capture converted string for later comparison
$converted_string = $str;
// Remove Strings that are never allowed
@@ -351,11 +429,11 @@ class CI_Security {
// 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', "&lt;?\\1", $str);
+ $str = preg_replace('/<\?(php)/i', '&lt;?\\1', $str);
}
else
{
- $str = str_replace(array('<?', '?'.'>'), array('&lt;?', '?&gt;'), $str);
+ $str = str_replace(array('<?', '?'.'>'), array('&lt;?', '?&gt;'), $str);
}
/*
@@ -365,56 +443,54 @@ class CI_Security {
* These words are compacted back to their correct state.
*/
$words = array(
- 'javascript', 'expression', 'vbscript', 'script', 'base64',
- 'applet', 'alert', 'document', 'write', 'cookie', 'window'
+ 'javascript', 'expression', 'vbscript', 'jscript', 'wscript',
+ 'vbs', 'script', 'base64', 'applet', 'alert', 'document',
+ 'write', 'cookie', 'window', 'confirm', 'prompt', 'eval'
);
foreach ($words as $word)
{
- $temp = '';
-
- for ($i = 0, $wordlen = strlen($word); $i < $wordlen; $i++)
- {
- $temp .= substr($word, $i, 1)."\s*";
- }
+ $word = implode('\s*', str_split($word)).'\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);
+ $str = preg_replace_callback('#('.substr($word, 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,
+ * We used to do some version comparisons and use of stripos(),
* but it is dog slow compared to these simplified non-capturing
* preg_match(), especially if the pattern exists in the string
+ *
+ * Note: It was reported that not only space characters, but all in
+ * the following pattern can be parsed as separators between a tag name
+ * and its attributes: [\d\s"\'`;,\/\=\(\x00\x0B\x09\x0C]
+ * ... however, remove_invisible_characters() above already strips the
+ * hex-encoded ones, so we'll skip them below.
*/
do
{
$original = $str;
- if (preg_match("/<a/i", $str))
+ if (preg_match('/<a/i', $str))
{
- $str = preg_replace_callback("#<a\s+([^>]*?)(>|$)#si", array($this, '_js_link_removal'), $str);
+ $str = preg_replace_callback('#<a(?:rea)?[^a-z0-9>]+([^>]*?)(?:>|$)#si', array($this, '_js_link_removal'), $str);
}
- if (preg_match("/<img/i", $str))
+ if (preg_match('/<img/i', $str))
{
- $str = preg_replace_callback("#<img\s+([^>]*?)(\s?/?>|$)#si", array($this, '_js_img_removal'), $str);
+ $str = preg_replace_callback('#<img[^a-z0-9]+([^>]*?)(?:\s?/?>|$)#si', array($this, '_js_img_removal'), $str);
}
- if (preg_match("/script/i", $str) OR preg_match("/xss/i", $str))
+ if (preg_match('/script|xss/i', $str))
{
- $str = preg_replace("#<(/*)(script|xss)(.*?)\>#si", '[removed]', $str);
+ $str = preg_replace('#</*(?:script|xss).*?>#si', '[removed]', $str);
}
}
- while($original != $str);
-
+ while ($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
*
@@ -424,23 +500,47 @@ class CI_Security {
* So this: <blink>
* Becomes: &lt;blink&gt;
*/
- $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);
+ $pattern = '#'
+ .'<((?<slash>/*\s*)((?<tagName>[a-z0-9]+)(?=[^a-z0-9]|$)|.+)' // tag start and name, followed by a non-tag character
+ .'[^\s\042\047a-z0-9>/=]*' // a valid attribute character immediately after the tag would count as a separator
+ // optional attributes
+ .'(?<attributes>(?:[\s\042\047/=]*' // non-attribute characters, excluding > (tag close) for obvious reasons
+ .'[^\s\042\047>/=]+' // attribute characters
+ // optional attribute-value
+ .'(?:\s*=' // attribute-value separator
+ .'(?:[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*))' // single, double or non-quoted value
+ .')?' // end optional attribute-value group
+ .')*)' // end optional attributes group
+ .'[^>]*)(?<closeTag>\>)?#isS';
+
+ // Note: It would be nice to optimize this for speed, BUT
+ // only matching the naughty elements here results in
+ // false positives and in turn - vulnerabilities!
+ do
+ {
+ $old_str = $str;
+ $str = preg_replace_callback($pattern, array($this, '_sanitize_naughty_html'), $str);
+ }
+ while ($old_str !== $str);
+ unset($old_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
+ * 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&#40;'some code'&#41;
+ * Becomes: eval&#40;'some code'&#41;
*/
- $str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);
-
+ $str = preg_replace(
+ '#(alert|prompt|confirm|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si',
+ '\\1\\2&#40;\\3&#41;',
+ $str
+ );
// Final clean up
// This adds a bit of extra precaution in case
@@ -456,29 +556,32 @@ class CI_Security {
* string post-removal of XSS, then it fails, as there was unwanted XSS
* code found and removed/changed during processing.
*/
-
if ($is_image === TRUE)
{
- return ($str == $converted_string) ? TRUE: FALSE;
+ return ($str === $converted_string);
}
- log_message('debug', "XSS Filtering completed");
return $str;
}
// --------------------------------------------------------------------
/**
- * Random Hash for protecting URLs
+ * XSS Hash
*
- * @return string
+ * Generates the XSS hash if needed and returns it.
+ *
+ * @see CI_Security::$_xss_hash
+ * @return string XSS hash
*/
public function xss_hash()
{
- if ($this->_xss_hash == '')
+ if ($this->_xss_hash === NULL)
{
- mt_srand();
- $this->_xss_hash = md5(time() + mt_rand(0, 1999999999));
+ $rand = $this->get_random_bytes(16);
+ $this->_xss_hash = ($rand === FALSE)
+ ? md5(uniqid(mt_rand(), TRUE))
+ : bin2hex($rand);
}
return $this->_xss_hash;
@@ -487,76 +590,158 @@ class CI_Security {
// --------------------------------------------------------------------
/**
+ * Get random bytes
+ *
+ * @param int $length Output length
+ * @return string
+ */
+ public function get_random_bytes($length)
+ {
+ if (empty($length) OR ! ctype_digit((string) $length))
+ {
+ return FALSE;
+ }
+
+ if (function_exists('random_bytes'))
+ {
+ try
+ {
+ // The cast is required to avoid TypeError
+ return random_bytes((int) $length);
+ }
+ catch (Exception $e)
+ {
+ // If random_bytes() can't do the job, we can't either ...
+ // There's no point in using fallbacks.
+ log_message('error', $e->getMessage());
+ return FALSE;
+ }
+ }
+
+ // Unfortunately, none of the following PRNGs is guaranteed to exist ...
+ if (defined('MCRYPT_DEV_URANDOM') && ($output = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM)) !== FALSE)
+ {
+ return $output;
+ }
+
+
+ if (is_readable('/dev/urandom') && ($fp = fopen('/dev/urandom', 'rb')) !== FALSE)
+ {
+ // Try not to waste entropy ...
+ is_php('5.4') && stream_set_chunk_size($fp, $length);
+ $output = fread($fp, $length);
+ fclose($fp);
+ if ($output !== FALSE)
+ {
+ return $output;
+ }
+ }
+
+ if (function_exists('openssl_random_pseudo_bytes'))
+ {
+ return openssl_random_pseudo_bytes($length);
+ }
+
+ return FALSE;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
* HTML Entities Decode
*
- * This function is a replacement for html_entity_decode()
+ * A replacement for html_entity_decode()
*
* The reason we are not using html_entity_decode() by itself is because
* while it is not technically 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
+ * correctly. html_entity_decode() does not convert entities without
* semicolons, so we are left with our own little solution here. Bummer.
*
- * @param string
- * @param string
+ * @link http://php.net/html-entity-decode
+ *
+ * @param string $str Input
+ * @param string $charset Character set
* @return string
*/
- public function entity_decode($str, $charset='UTF-8')
+ public function entity_decode($str, $charset = NULL)
{
- if (stristr($str, '&') === FALSE)
+ if (strpos($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);
+ static $_entities;
+
+ isset($charset) OR $charset = $this->charset;
+ $flag = is_php('5.4')
+ ? ENT_COMPAT | ENT_HTML5
+ : ENT_COMPAT;
+
+ if ( ! isset($_entities))
+ {
+ $_entities = array_map('strtolower', get_html_translation_table(HTML_ENTITIES, $flag, $charset));
+
+ // If we're not on PHP 5.4+, add the possibly dangerous HTML 5
+ // entities to the array manually
+ if ($flag === ENT_COMPAT)
+ {
+ $_entities[':'] = '&colon;';
+ $_entities['('] = '&lpar;';
+ $_entities[')'] = '&rpar;';
+ $_entities["\n"] = '&NewLine;';
+ $_entities["\t"] = '&Tab;';
+ }
+ }
+
+ do
+ {
+ $str_compare = $str;
+
+ // Decode standard entities, avoiding false positives
+ if (preg_match_all('/&[a-z]{2,}(?![a-z;])/i', $str, $matches))
+ {
+ $replace = array();
+ $matches = array_unique(array_map('strtolower', $matches[0]));
+ foreach ($matches as &$match)
+ {
+ if (($char = array_search($match.';', $_entities, TRUE)) !== FALSE)
+ {
+ $replace[$match] = $char;
+ }
+ }
+
+ $str = str_replace(array_keys($replace), array_values($replace), $str);
+ }
+
+ // Decode numeric & UTF16 two byte entities
+ $str = html_entity_decode(
+ preg_replace('/(&#(?:x0*[0-9a-f]{2,5}(?![0-9a-f;])|(?:0*\d{2,4}(?![0-9;]))))/iS', '$1;', $str),
+ $flag,
+ $charset
+ );
+
+ if ($flag === ENT_COMPAT)
+ {
+ $str = str_replace(array_values($_entities), array_keys($_entities), $str);
+ }
+ }
+ while ($str_compare !== $str);
+ return $str;
}
// --------------------------------------------------------------------
/**
- * Filename Security
+ * Sanitize Filename
*
- * @param string
- * @param bool
+ * @param string $str Input file name
+ * @param bool $relative_path Whether to preserve paths
* @return string
*/
public function sanitize_filename($str, $relative_path = FALSE)
{
- $bad = array(
- "../",
- "<!--",
- "-->",
- "<",
- ">",
- "'",
- '"',
- '&',
- '$',
- '#',
- '{',
- '}',
- '[',
- ']',
- '=',
- ';',
- '?',
- "%20",
- "%22",
- "%3c", // <
- "%253c", // <
- "%3e", // >
- "%0e", // >
- "%28", // (
- "%29", // )
- "%2528", // (
- "%26", // &
- "%24", // $
- "%3f", // ?
- "%3b", // ;
- "%3d" // =
- );
+ $bad = $this->filename_bad_chars;
if ( ! $relative_path)
{
@@ -565,7 +750,53 @@ class CI_Security {
}
$str = remove_invisible_characters($str, FALSE);
- return stripslashes(str_replace($bad, '', $str));
+
+ do
+ {
+ $old = $str;
+ $str = str_replace($bad, '', $str);
+ }
+ while ($old !== $str);
+
+ return stripslashes($str);
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * Strip Image Tags
+ *
+ * @param string $str
+ * @return string
+ */
+ public function strip_image_tags($str)
+ {
+ return preg_replace(
+ array(
+ '#<img[\s/]+.*?src\s*=\s*(["\'])([^\\1]+?)\\1.*?\>#i',
+ '#<img[\s/]+.*?src\s*=\s*?(([^\s"\'=<>`]+)).*?\>#i'
+ ),
+ '\\2',
+ $str
+ );
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * URL-decode taking spaces into account
+ *
+ * @see https://github.com/bcit-ci/CodeIgniter/issues/4877
+ * @param array $matches
+ * @return string
+ */
+ protected function _urldecodespaces($matches)
+ {
+ $input = $matches[0];
+ $nospaces = preg_replace('#\s+#', '', $input);
+ return ($nospaces === $input)
+ ? $input
+ : rawurldecode($nospaces);
}
// ----------------------------------------------------------------
@@ -573,11 +804,12 @@ class CI_Security {
/**
* Compact Exploded Words
*
- * Callback function for xss_clean() to remove whitespace from
- * things like j a v a s c r i p t
+ * Callback method for xss_clean() to remove whitespace from
+ * things like 'j a v a s c r i p t'.
*
- * @param type
- * @return type
+ * @used-by CI_Security::xss_clean()
+ * @param array $matches
+ * @return string
*/
protected function _compact_exploded_words($matches)
{
@@ -586,86 +818,93 @@ class CI_Security {
// --------------------------------------------------------------------
- /*
- * Remove Evil HTML Attributes (like evenhandlers and style)
+ /**
+ * Sanitize Naughty HTML
*
- * 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">
+ * Callback method for xss_clean() to remove naughty HTML elements.
*
- * @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
+ * @used-by CI_Security::xss_clean()
+ * @param array $matches
+ * @return string
*/
- protected function _remove_evil_attributes($str, $is_image)
+ protected function _sanitize_naughty_html($matches)
{
- // All javascript event handlers (e.g. onload, onclick, onmouseover), style, and xmlns
- $evil_attributes = array('on\w*', 'style', 'xmlns', 'formaction');
+ static $naughty_tags = array(
+ 'alert', 'area', 'prompt', 'confirm', 'applet', 'audio', 'basefont', 'base', 'behavior', 'bgsound',
+ 'blink', 'body', 'embed', 'expression', 'form', 'frameset', 'frame', 'head', 'html', 'ilayer',
+ 'iframe', 'input', 'button', 'select', 'isindex', 'layer', 'link', 'meta', 'keygen', 'object',
+ 'plaintext', 'style', 'script', 'textarea', 'title', 'math', 'video', 'svg', 'xml', 'xss'
+ );
- if ($is_image === TRUE)
+ static $evil_attributes = array(
+ 'on\w+', 'style', 'xmlns', 'formaction', 'form', 'xlink:href', 'FSCommand', 'seekSegmentTime'
+ );
+
+ // First, escape unclosed tags
+ if (empty($matches['closeTag']))
+ {
+ return '&lt;'.$matches[1];
+ }
+ // Is the element that we caught naughty? If so, escape it
+ elseif (in_array(strtolower($matches['tagName']), $naughty_tags, TRUE))
{
- /*
- * Adobe Photoshop puts XML metadata into JFIF images,
- * including namespacing, so we have to allow this for images.
- */
- unset($evil_attributes[array_search('xmlns', $evil_attributes)]);
+ return '&lt;'.$matches[1].'&gt;';
}
+ // For other tags, see if their attributes are "evil" and strip those
+ elseif (isset($matches['attributes']))
+ {
+ // We'll store the already fitlered attributes here
+ $attributes = array();
- do {
- $count = 0;
- $attribs = array();
+ // Attribute-catching pattern
+ $attributes_pattern = '#'
+ .'(?<name>[^\s\042\047>/=]+)' // attribute characters
+ // optional attribute-value
+ .'(?:\s*=(?<value>[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*)))' // attribute-value separator
+ .'#i';
- // 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);
+ // Blacklist pattern for evil attribute names
+ $is_evil_pattern = '#^('.implode('|', $evil_attributes).')$#i';
- foreach ($matches as $attr)
+ // Each iteration filters a single attribute
+ do
{
- $attribs[] = preg_quote($attr[0], '/');
- }
+ // Strip any non-alpha characters that may precede an attribute.
+ // Browsers often parse these incorrectly and that has been a
+ // of numerous XSS issues we've had.
+ $matches['attributes'] = preg_replace('#^[^a-z]+#i', '', $matches['attributes']);
- // find occurrences of illegal attribute strings without quotes
- preg_match_all('/('.implode('|', $evil_attributes).')\s*=\s*([^\s>]*)/is', $str, $matches, PREG_SET_ORDER);
+ if ( ! preg_match($attributes_pattern, $matches['attributes'], $attribute, PREG_OFFSET_CAPTURE))
+ {
+ // No (valid) attribute found? Discard everything else inside the tag
+ break;
+ }
- foreach ($matches as $attr)
- {
- $attribs[] = preg_quote($attr[0], '/');
- }
+ if (
+ // Is it indeed an "evil" attribute?
+ preg_match($is_evil_pattern, $attribute['name'][0])
+ // Or does it have an equals sign, but no value and not quoted? Strip that too!
+ OR (trim($attribute['value'][0]) === '')
+ )
+ {
+ $attributes[] = 'xss=removed';
+ }
+ else
+ {
+ $attributes[] = $attribute[0][0];
+ }
- // replace illegal attribute strings that are inside an html tag
- if (count($attribs) > 0)
- {
- $str = preg_replace('/(<?)(\/?[^><]+?)([^A-Za-z<>\-])(.*?)('.implode('|', $attribs).')(.*?)([\s><]?)([><]*)/i', '$1$2 $4$6$7$8', $str, -1, $count);
+ $matches['attributes'] = substr($matches['attributes'], $attribute[0][1] + strlen($attribute[0][0]));
}
+ while ($matches['attributes'] !== '');
- } while ($count);
-
- return $str;
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Sanitize Naughty HTML
- *
- * Callback function for xss_clean() to remove naughty HTML elements
- *
- * @param array
- * @return string
- */
- protected function _sanitize_naughty_html($matches)
- {
- // encode opening brace
- $str = '&lt;'.$matches[1].$matches[2].$matches[3];
-
- // encode captured opening or closing brace to prevent recursive vectors
- $str .= str_replace(array('>', '<'), array('&gt;', '&lt;'),
- $matches[4]);
+ $attributes = empty($attributes)
+ ? ''
+ : ' '.implode(' ', $attributes);
+ return '<'.$matches['slash'].$matches['tagName'].$attributes.'>';
+ }
- return $str;
+ return $matches[0];
}
// --------------------------------------------------------------------
@@ -673,12 +912,14 @@ class CI_Security {
/**
* JS Link Removal
*
- * Callback function for xss_clean() to sanitize links
+ * Callback method 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
+ * PHP 5.2+ on link-heavy strings.
*
- * @param array
+ * @used-by CI_Security::xss_clean()
+ * @param array $match
* @return string
*/
protected function _js_link_removal($match)
@@ -686,9 +927,9 @@ class CI_Security {
return str_replace(
$match[1],
preg_replace(
- '#href=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|data\s*:)#si',
+ '#href=.*?(?:(?:alert|prompt|confirm)(?:\(|&\#40;)|javascript:|livescript:|mocha:|charset=|window\.|document\.|\.cookie|<script|<xss|d\s*a\s*t\s*a\s*:)#si',
'',
- $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]))
+ $this->_filter_attributes($match[1])
),
$match[0]
);
@@ -699,12 +940,14 @@ class CI_Security {
/**
* JS Image Removal
*
- * Callback function for xss_clean() to sanitize image tags
+ * Callback method 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
+ * PHP 5.2+ on image tag heavy strings.
*
- * @param array
+ * @used-by CI_Security::xss_clean()
+ * @param array $match
* @return string
*/
protected function _js_img_removal($match)
@@ -712,9 +955,9 @@ class CI_Security {
return str_replace(
$match[1],
preg_replace(
- '#src=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si',
+ '#src=.*?(?:(?:alert|prompt|confirm|eval)(?:\(|&\#40;)|javascript:|livescript:|mocha:|charset=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si',
'',
- $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]))
+ $this->_filter_attributes($match[1])
),
$match[0]
);
@@ -725,9 +968,8 @@ class CI_Security {
/**
* Attribute Conversion
*
- * Used as a callback for XSS Clean
- *
- * @param array
+ * @used-by CI_Security::xss_clean()
+ * @param array $match
* @return string
*/
protected function _convert_attribute($match)
@@ -740,20 +982,21 @@ class CI_Security {
/**
* Filter Attributes
*
- * Filters tag attributes for consistency and safety
+ * Filters tag attributes for consistency and safety.
*
- * @param string
+ * @used-by CI_Security::_js_img_removal()
+ * @used-by CI_Security::_js_link_removal()
+ * @param string $str
* @return string
*/
protected function _filter_attributes($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);
+ $out .= preg_replace('#/\*.*?\*/#s', '', $match);
}
}
@@ -765,68 +1008,30 @@ class CI_Security {
/**
* HTML Entity Decode Callback
*
- * Used as a callback for XSS Clean
- *
- * @param array
+ * @used-by CI_Security::xss_clean()
+ * @param array $match
* @return string
*/
protected function _decode_entity($match)
{
- return $this->entity_decode($match[0], strtoupper(config_item('charset')));
- }
-
- // --------------------------------------------------------------------
-
- /**
- * Validate URL entities
- *
- * Called by xss_clean()
- *
- * @param string
- * @return string
- */
- 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);
+ // Protect GET variables in URLs
+ // 901119URL5918AMP18930PROTECT8198
+ $match = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-/]+)|i', $this->xss_hash().'\\1=\\2', $match[0]);
- /*
- * 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;
+ // Decode, then un-protect URL GET vars
+ return str_replace(
+ $this->xss_hash(),
+ '&',
+ $this->entity_decode($match, $this->charset)
+ );
}
- // ----------------------------------------------------------------------
+ // --------------------------------------------------------------------
/**
* Do Never Allowed
*
- * A utility function for xss_clean()
- *
+ * @used-by CI_Security::xss_clean()
* @param string
* @return string
*/
@@ -845,31 +1050,31 @@ class CI_Security {
// --------------------------------------------------------------------
/**
- * Set Cross Site Request Forgery Protection Cookie
+ * Set CSRF Hash and Cookie
*
* @return string
*/
protected function _csrf_set_hash()
{
- if ($this->_csrf_hash == '')
+ if ($this->_csrf_hash === NULL)
{
- // If the cookie exists we will use it's value.
+ // If the cookie exists we will use its value.
// We don't necessarily want to regenerate it with
// each page load since a page could contain embedded
// sub-pages causing this feature to fail
- if (isset($_COOKIE[$this->_csrf_cookie_name]) &&
- preg_match('#^[0-9a-f]{32}$#iS', $_COOKIE[$this->_csrf_cookie_name]) === 1)
+ if (isset($_COOKIE[$this->_csrf_cookie_name]) && is_string($_COOKIE[$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));
+ $rand = $this->get_random_bytes(16);
+ $this->_csrf_hash = ($rand === FALSE)
+ ? md5(uniqid(mt_rand(), TRUE))
+ : bin2hex($rand);
}
return $this->_csrf_hash;
}
}
-
-/* End of file Security.php */
-/* Location: ./system/libraries/Security.php */