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sterzycom/kirby/toolkit/lib/escape.php

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update to version 2.3 and remove submodules
2016-05-26 21:02:48 +02:00
<?php
/**
* Escape
*
* Class to handle context specific output escaping per OWASP recommendations.
*
* Most of this class is based on methods from Zend\Escaper, but modified for Kirby.
* Copyrighted (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* under the New BSD License (http://framework.zend.com/license/new-bsd).
*
* @link https://github.com/zendframework/zf2/blob/master/library/Zend/Escaper/Escaper.php
* @link https://www.owasp.org/index.php/XSS_(Cross_Site_Scripting)_Prevention_Cheat_Sheet
*
* @package Kirby Toolkit
* @author Ezra Verheijen <ezra.verheijen@gmail.com>
* @link https://github.com/ezraverheijen/escape
* @copyright Ezra Verheijen
* @license http://www.opensource.org/licenses/mit-license.php MIT License
*/
class Escape {
/**
* Check if a string needs to be escaped or not
*
* @param string $string
* @return boolean
*/
public static function noNeedToEscape($string) {
return $string === '' || ctype_digit($string);
}
/**
* Convert a character from UTF-8 to UTF-16BE
*
* @param string $char
* @return string
*/
public static function convertEncoding($char) {
return str::convert($char, 'UTF-16BE', 'UTF-8');
}
/**
* Check if a character is undefined in HTML
*
* @param string $char
* @return boolean
*/
public static function charIsUndefined($char) {
$ascii = ord($char);
return ($ascii <= 0x1f && $char != "\t" && $char != "\n" && $char != "\r")
|| ($ascii >= 0x7f && $ascii <= 0x9f);
}
/**
* Escape HTML element content
*
* This can be used to put untrusted data directly into the HTML body somewhere.
* This includes inside normal tags like div, p, b, td, etc.
*
* Escapes &, <, >, ", and ' with HTML entity encoding to prevent switching
* into any execution context, such as script, style, or event handlers.
*
* <body>...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...</body>
* <div>...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...</div>
*
* @uses ENT_SUBSTITUE if available (PHP >= 5.4)
*
* @param string $string
* @return string
*/
public static function html($string) {
$flags = ENT_QUOTES;
if(defined('ENT_SUBSTITUTE')) {
$flags |= ENT_SUBSTITUTE;
}
return htmlspecialchars($string, $flags, 'UTF-8');
}
/**
* Escape XML element content
*
* Removes offending characters that could be wrongfully interpreted as XML markup.
*
* The following characters are reserved in XML and will be replaced with their
* corresponding XML entities:
*
* ' is replaced with &apos;
* " is replaced with &quot;
* & is replaced with &amp;
* < is replaced with &lt;
* > is replaced with &gt;
*
* @uses ENT_XML1 if available (PHP >= 5.4)
*
* @param string $string
* @return string
*/
public static function xml($string) {
if (defined('ENT_XML1')) {
return htmlspecialchars($string, ENT_QUOTES | ENT_XML1, 'UTF-8');
} else {
return str_replace('&#039;', '&apos;', htmlspecialchars($string, ENT_QUOTES, 'UTF-8'));
}
}
/**
* Escape common HTML attributes data
*
* This can be used to put untrusted data into typical attribute values
* like width, name, value, etc.
*
* This should not be used for complex attributes like href, src, style,
* or any of the event handlers like onmouseover.
* Use esc($string, 'js') for event handler attributes, esc($string, 'url')
* for src attributes and esc($string, 'css') for style attributes.
*
* <div attr=...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...>content</div>
* <div attr='...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...'>content</div>
* <div attr="...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...">content</div>
*
* @param string $string
* @param string $strict Whether to escape characters like [space] % * + , - / ; < = > ^ and |
* which is necessary in case of unquoted HTML attributes.
* @return string
*/
public static function attr($string, $strict = false) {
if(static::noNeedToEscape($string)) return $string;
if($strict !== true) {
return preg_replace_callback('/[^a-z0-9,\.\-_]/iSu', 'static::escapeAttrChar', $string);
}
return static::html($string);
}
/**
* Escape JavaScript data values
*
* This can be used to put dynamically generated JavaScript code
* into both script blocks and event-handler attributes.
*
* <script>alert('...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...')</script>
* <script>x='...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...'</script>
* <div onmouseover="x='...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...'"</div>
*
* @param string $string
* @return string
*/
public static function js($string) {
if(static::noNeedToEscape($string)) return $string;
return preg_replace_callback('/[^a-z0-9,\._]/iSu', 'static::escapeJSChar', $string);
}
/**
* Escape HTML style property values
*
* This can be used to put untrusted data into a stylesheet or a style tag.
*
* Stay away from putting untrusted data into complex properties like url,
* behavior, and custom (-moz-binding). You should also not put untrusted data
* into IE’s expression property value which allows JavaScript.
*
* <style>selector { property : ...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...; } </style>
* <style>selector { property : "...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE..."; } </style>
* <span style="property : ...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...">text</span>
*
* @param string $string
* @return string
*/
public static function css($string) {
if(static::noNeedToEscape($string)) return $string;
return preg_replace_callback('/[^a-z0-9]/iSu', 'static::escapeCSSChar', $string);
}
/**
* Escape URL parameter values
*
* This can be used to put untrusted data into HTTP GET parameter values.
* This should not be used to escape an entire URI.
*
* <a href="http://www.somesite.com?test=...ESCAPE UNTRUSTED DATA BEFORE PUTTING HERE...">link</a>
*
* @param string $string
* @return string
*/
public static function url($string) {
return rawurlencode($string);
}
/**
* Escape character for HTML attribute
*
* Callback function for preg_replace_callback() that applies HTML attribute
* escaping to all matches.
*
* @param array $matches
* @return mixed Unicode replacement if character is undefined in HTML,
* named HTML entity if available (only those that XML supports),
* upper hex entity if a named entity does not exist or
* entity with the &#xHH; format if ASCII value is less than 256.
*/
protected static function escapeAttrChar($matches) {
$char = $matches[0];
if(static::charIsUndefined($char)) {
return '&#xFFFD;';
}
$dec = hexdec(bin2hex($char));
$namedEntities = array(
34 => '&quot;', // "
38 => '&amp;', // &
60 => '&lt;', // <
62 => '&gt;' // >
);
if(isset($namedEntities[$dec])) {
return $namedEntities[$dec];
}
if($dec > 255) {
return sprintf('&#x%04X;', $dec);
}
return sprintf('&#x%02X;', $dec);
}
/**
* Escape character for JavaScript
*
* Callback function for preg_replace_callback() that applies Javascript
* escaping to all matches.
*
* @param array $matches
* @return string
*/
protected static function escapeJSChar($matches) {
$char = $matches[0];
if(str::length($char) == 1) {
return sprintf('\\x%02X', ord($char));
}
$char = static::convertEncoding($char);
return sprintf('\\u%04s', str::upper(bin2hex($char)));
}
/**
* Escape character for CSS
*
* Callback function for preg_replace_callback() that applies CSS
* escaping to all matches.
*
* @param array $matches
* @return string
*/
protected static function escapeCSSChar($matches) {
$char = $matches[0];
if(str::length($char) == 1) {
$ord = ord($char);
} else {
$char = static::convertEncoding($char);
$ord = hexdec(bin2hex($char));
}
return sprintf('\\%X ', $ord);
}
}
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