From ffac99eadc1751a428d286a095a6da3cea2da934 Mon Sep 17 00:00:00 2001
From: Ryan Boren <ryan@boren.nu>
Date: Mon, 10 Sep 2012 16:19:54 +0000
Subject: [PATCH]  * Introduce wp_kses_allowed_html() which accepts a context
 string and returns an array of allowed tags.  * Remove explicit declarations
 of class, id, style, and title from $allowedposttags  * Dynamicallly add
 global attributes to every tag for the 'post' context  * No longer calls
 wp_kses_array_lc() every time wp_kses() runs. Instead it runs once if
 CUSTOM_TAGS is true. Plugins directly passing a custom allowed_html array
 will no longer get the lc treatment. Keep an eye out for problems with this. 
 * wp_kses_data() and wp_filter_kses() pass current_filter() for the
 $allowed_html argument to wp_kses().  * wp_kses_allowed_html() handles being
 passed a filter name for a context. If the filter is not a recognized one it
 defaults to using $allowedtags as was done before for wp_kses_data() and
 wp_filter_kses().  * wp_kses_allowed_html() recognizes user_description and
 pre_user_description out of the box. For these it takes $allowedtags and
 inserts rel attribute support.  * wp_kses_allowed_html() allows plugins to
 override the return values for the default contexts and support arbitrary
 contexts via a wp_kses_allowed_html filter.  * wp_kses_hook() can now pass a
 string context for $allowed_html to the pre_kses filter. We might have to
 pass the result of wp_kses_allowed_html() instead if it turns out that
 plugins are digging in $allowed_html.

fixes #17977
see #20210


git-svn-id: http://core.svn.wordpress.org/trunk@21790 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/kses.php | 240 +++++++++++++++++++++----------------------
 1 file changed, 117 insertions(+), 123 deletions(-)

diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index 0754dabb8f..a04590e180 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -51,50 +51,42 @@ if ( ! CUSTOM_TAGS ) {
 	$allowedposttags = array(
 		'address' => array(),
 		'a' => array(
-			'class' => true,
 			'href' => true,
-			'id' => true,
-			'title' => true,
 			'rel' => true,
 			'rev' => true,
 			'name' => true,
 			'target' => true,
 		),
-		'abbr' => array(
-			'class' => true,
-			'title' => true,
-		),
-		'acronym' => array(
-			'title' => true,
+		'abbr' => array(),
+		'acronym' => array(),
+		'area' => array(
+			'alt' => true,
+			'coords' => true,
+			'href' => true,
+			'nohref' => true,
+			'shape' => true,
+			'target' => true,
 		),
 		'article' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'aside' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'b' => array(),
 		'big' => array(),
 		'blockquote' => array(
-			'id' => true,
 			'cite' => true,
-			'class' => true,
 			'lang' => true,
 			'xml:lang' => true,
 		),
-		'br' => array (
-			'class' => true,
-		),
+		'br' => array(),
 		'button' => array(
 			'disabled' => true,
 			'name' => true,
@@ -103,24 +95,18 @@ if ( ! CUSTOM_TAGS ) {
 		),
 		'caption' => array(
 			'align' => true,
-			'class' => true,
 		),
-		'cite' => array (
-			'class' => true,
+		'cite' => array(
 			'dir' => true,
 			'lang' => true,
-			'title' => true,
-		),
-		'code' => array (
-			'style' => true,
 		),
+		'code' => array(),
 		'col' => array(
 			'align' => true,
 			'char' => true,
 			'charoff' => true,
 			'span' => true,
 			'dir' => true,
-			'style' => true,
 			'valign' => true,
 			'width' => true,
 		),
@@ -130,19 +116,15 @@ if ( ! CUSTOM_TAGS ) {
 		'dd' => array(),
 		'details' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
 			'open' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'div' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'dl' => array(),
@@ -151,18 +133,14 @@ if ( ! CUSTOM_TAGS ) {
 		'fieldset' => array(),
 		'figure' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'figcaption' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'font' => array(
@@ -172,10 +150,8 @@ if ( ! CUSTOM_TAGS ) {
 		),
 		'footer' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'form' => array(
@@ -189,59 +165,36 @@ if ( ! CUSTOM_TAGS ) {
 		),
 		'h1' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
-		'h2' => array (
+		'h2' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
-		'h3' => array (
+		'h3' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
-		'h4' => array (
+		'h4' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
-		'h5' => array (
+		'h5' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
-		'h6' => array (
+		'h6' => array(
 			'align' => true,
-			'class' => true,
-			'id'    => true,
-			'style' => true,
 		),
 		'header' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'hgroup' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
-		'hr' => array (
+		'hr' => array(
 			'align' => true,
-			'class' => true,
 			'noshade' => true,
 			'size' => true,
 			'width' => true,
@@ -251,13 +204,12 @@ if ( ! CUSTOM_TAGS ) {
 			'alt' => true,
 			'align' => true,
 			'border' => true,
-			'class' => true,
 			'height' => true,
 			'hspace' => true,
 			'longdesc' => true,
 			'vspace' => true,
 			'src' => true,
-			'style' => true,
+			'usemap' => true,
 			'width' => true,
 		),
 		'ins' => array(
@@ -271,54 +223,44 @@ if ( ! CUSTOM_TAGS ) {
 		'legend' => array(
 			'align' => true,
 		),
-		'li' => array (
+		'li' => array(
 			'align' => true,
-			'class' => true,
 		),
-		'menu' => array (
-			'class' => true,
-			'style' => true,
+		'map' => array(
+			'name' => true,
+		),
+		'menu' => array(
 			'type' => true,
 		),
 		'nav' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'p' => array(
-			'class' => true,
 			'align' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'pre' => array(
-			'style' => true,
 			'width' => true,
 		),
 		'q' => array(
 			'cite' => true,
 		),
 		's' => array(),
-		'span' => array (
-			'class' => true,
+		'span' => array(
 			'dir' => true,
 			'align' => true,
 			'lang' => true,
-			'style' => true,
-			'title' => true,
 			'xml:lang' => true,
 		),
 		'section' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'small' => array(),
@@ -327,10 +269,8 @@ if ( ! CUSTOM_TAGS ) {
 		'sub' => array(),
 		'summary' => array(
 			'align' => true,
-			'class' => true,
 			'dir' => true,
 			'lang' => true,
-			'style' => true,
 			'xml:lang' => true,
 		),
 		'sup' => array(),
@@ -340,11 +280,8 @@ if ( ! CUSTOM_TAGS ) {
 			'border' => true,
 			'cellpadding' => true,
 			'cellspacing' => true,
-			'class' => true,
 			'dir' => true,
-			'id' => true,
 			'rules' => true,
-			'style' => true,
 			'summary' => true,
 			'width' => true,
 		),
@@ -361,7 +298,6 @@ if ( ! CUSTOM_TAGS ) {
 			'bgcolor' => true,
 			'char' => true,
 			'charoff' => true,
-			'class' => true,
 			'colspan' => true,
 			'dir' => true,
 			'headers' => true,
@@ -369,7 +305,6 @@ if ( ! CUSTOM_TAGS ) {
 			'nowrap' => true,
 			'rowspan' => true,
 			'scope' => true,
-			'style' => true,
 			'valign' => true,
 			'width' => true,
 		),
@@ -383,7 +318,6 @@ if ( ! CUSTOM_TAGS ) {
 		'tfoot' => array(
 			'align' => true,
 			'char' => true,
-			'class' => true,
 			'charoff' => true,
 			'valign' => true,
 		),
@@ -394,7 +328,6 @@ if ( ! CUSTOM_TAGS ) {
 			'bgcolor' => true,
 			'char' => true,
 			'charoff' => true,
-			'class' => true,
 			'colspan' => true,
 			'headers' => true,
 			'height' => true,
@@ -408,7 +341,6 @@ if ( ! CUSTOM_TAGS ) {
 			'align' => true,
 			'char' => true,
 			'charoff' => true,
-			'class' => true,
 			'valign' => true,
 		),
 		'title' => array(),
@@ -417,21 +349,15 @@ if ( ! CUSTOM_TAGS ) {
 			'bgcolor' => true,
 			'char' => true,
 			'charoff' => true,
-			'class' => true,
-			'style' => true,
 			'valign' => true,
 		),
 		'tt' => array(),
 		'u' => array(),
-		'ul' => array (
-			'class' => true,
-			'style' => true,
+		'ul' => array(
 			'type' => true,
 		),
-		'ol' => array (
-			'class' => true,
+		'ol' => array(
 			'start' => true,
-			'style' => true,
 			'type' => true,
 		),
 		'var' => array(),
@@ -467,7 +393,8 @@ if ( ! CUSTOM_TAGS ) {
 		//	'dd' => array(),
 		//	'dl' => array(),
 		//	'dt' => array(),
-		'em' => array (), 'i' => array (),
+		'em' => array(),
+		'i' => array(),
 		//	'ins' => array('datetime' => array(), 'cite' => array()),
 		//	'li' => array(),
 		//	'ol' => array(),
@@ -526,6 +453,11 @@ if ( ! CUSTOM_TAGS ) {
 		'sdot',    'lceil',  'rceil',   'lfloor', 'rfloor', 'lang',
 		'rang',    'loz',    'spades',  'clubs',  'hearts', 'diams',
 	);
+
+	$allowedposttags = array_map( '_wp_add_global_attributes', $allowedposttags );
+} else {
+	$allowedtags = wp_kses_array_lc( $allowedtags );
+	$allowedposttags = wp_kses_array_lc( $allowedposttags );
 }
 
 /**
@@ -548,15 +480,51 @@ if ( ! CUSTOM_TAGS ) {
  * @param array $allowed_protocols Optional. Allowed protocol in links.
  * @return string Filtered content with only allowed HTML elements
  */
-function wp_kses($string, $allowed_html, $allowed_protocols = array ()) {
+function wp_kses( $string, $allowed_html, $allowed_protocols = array() ) {
 	if ( empty( $allowed_protocols ) )
 		$allowed_protocols = wp_allowed_protocols();
 	$string = wp_kses_no_null($string);
 	$string = wp_kses_js_entities($string);
 	$string = wp_kses_normalize_entities($string);
-	$allowed_html_fixed = wp_kses_array_lc($allowed_html);
-	$string = wp_kses_hook($string, $allowed_html_fixed, $allowed_protocols); // WP changed the order of these funcs and added args to wp_kses_hook
-	return wp_kses_split($string, $allowed_html_fixed, $allowed_protocols);
+	$string = wp_kses_hook($string, $allowed_html, $allowed_protocols); // WP changed the order of these funcs and added args to wp_kses_hook
+	return wp_kses_split($string, $allowed_html, $allowed_protocols);
+}
+
+/**
+ * Return a list of allowed tags and attributes for a given context.
+ *
+ * @since 3.5.0
+ *
+ * @param string $context The context for which to retrieve tags. Allowed values are
+ *  post | strip | data | entities or the name of a field filter such as pre_user_description.
+ * @return array List of allowed tags and their allowed attributes.
+ */
+function wp_kses_allowed_html( $context = '' ) {
+	global $allowedposttags, $allowedtags, $allowedentitynames;
+
+	if ( is_array( $context ) )
+		return apply_filters( 'wp_kses_allowed_html', $context, 'explicit' );
+
+	switch ( $context ) {
+		case 'post':
+			return apply_filters( 'wp_kses_allowed_html', $allowedposttags, $context );
+			break;
+		case 'user_description':
+		case 'pre_user_description':
+			$tags = $allowedtags;
+			$tags['a']['rel'] = true;
+			return apply_filters( 'wp_kses_allowed_html', $tags, $context );
+			break;
+		case 'strip':
+			return apply_filters( 'wp_kses_allowed_html', array(), $context );
+			break;
+		case 'entities':
+			return apply_filters( 'wp_kses_allowed_html', $allowedentitynames, $context);
+			break;
+		case 'data':
+		default:
+			return apply_filters( 'wp_kses_allowed_html', $allowedtags, $context );
+	}
 }
 
 /**
@@ -572,7 +540,7 @@ function wp_kses($string, $allowed_html, $allowed_protocols = array ()) {
  * @param array $allowed_protocols Allowed protocol in links
  * @return string Filtered content through 'pre_kses' hook
  */
-function wp_kses_hook($string, $allowed_html, $allowed_protocols) {
+function wp_kses_hook( $string, $allowed_html, $allowed_protocols ) {
 	$string = apply_filters('pre_kses', $string, $allowed_html, $allowed_protocols);
 	return $string;
 }
@@ -600,7 +568,7 @@ function wp_kses_version() {
  * @param array $allowed_protocols Allowed protocols to keep
  * @return string Content with fixed HTML tags
  */
-function wp_kses_split($string, $allowed_html, $allowed_protocols) {
+function wp_kses_split( $string, $allowed_html, $allowed_protocols ) {
 	global $pass_allowed_html, $pass_allowed_protocols;
 	$pass_allowed_html = $allowed_html;
 	$pass_allowed_protocols = $allowed_protocols;
@@ -668,6 +636,9 @@ function wp_kses_split2($string, $allowed_html, $allowed_protocols) {
 	$elem = $matches[2];
 	$attrlist = $matches[3];
 
+	if ( ! is_array( $allowed_html ) )
+		$allowed_html = wp_kses_allowed_html( $allowed_html );
+
 	if ( ! isset($allowed_html[strtolower($elem)]) )
 		return '';
 	# They are using a not allowed HTML element
@@ -699,6 +670,9 @@ function wp_kses_split2($string, $allowed_html, $allowed_protocols) {
 function wp_kses_attr($element, $attr, $allowed_html, $allowed_protocols) {
 	# Is there a closing XHTML slash at the end of the attributes?
 
+	if ( ! is_array( $allowed_html ) )
+		$allowed_html = wp_kses_allowed_html( $allowed_html );
+
 	$xhtml_slash = '';
 	if (preg_match('%\s*/\s*$%', $attr))
 		$xhtml_slash = ' /';
@@ -777,7 +751,7 @@ function wp_kses_attr($element, $attr, $allowed_html, $allowed_protocols) {
  * @return array List of attributes after parsing
  */
 function wp_kses_hair($attr, $allowed_protocols) {
-	$attrarr = array ();
+	$attrarr = array();
 	$mode = 0;
 	$attrname = '';
 	$uris = array('xmlns', 'profile', 'href', 'src', 'cite', 'classid', 'codebase', 'data', 'usemap', 'longdesc', 'action');
@@ -1286,9 +1260,8 @@ function _wp_kses_decode_entities_chr_hexdec( $match ) {
  * @param string $data Content to filter, expected to be escaped with slashes
  * @return string Filtered content
  */
-function wp_filter_kses($data) {
-	global $allowedtags;
-	return addslashes( wp_kses(stripslashes( $data ), $allowedtags) );
+function wp_filter_kses( $data ) {
+	return addslashes( wp_kses( stripslashes( $data ), current_filter() ) );
 }
 
 /**
@@ -1300,9 +1273,8 @@ function wp_filter_kses($data) {
  * @param string $data Content to filter, expected to not be escaped
  * @return string Filtered content
  */
-function wp_kses_data($data) {
-	global $allowedtags;
-	return wp_kses( $data , $allowedtags );
+function wp_kses_data( $data ) {
+	return wp_kses( $data , current_filter() );
 }
 
 /**
@@ -1312,14 +1284,12 @@ function wp_kses_data($data) {
  * data from forms.
  *
  * @since 2.0.0
- * @uses $allowedposttags
  *
  * @param string $data Post content to filter, expected to be escaped with slashes
  * @return string Filtered post content with allowed HTML tags and attributes intact.
  */
 function wp_filter_post_kses($data) {
-	global $allowedposttags;
-	return addslashes ( wp_kses(stripslashes( $data ), $allowedposttags) );
+	return addslashes ( wp_kses( stripslashes( $data ), 'post' ) );
 }
 
 /**
@@ -1329,14 +1299,12 @@ function wp_filter_post_kses($data) {
  * data from forms.
  *
  * @since 2.9.0
- * @uses $allowedposttags
  *
  * @param string $data Post content to filter
  * @return string Filtered post content with allowed HTML tags and attributes intact.
  */
 function wp_kses_post($data) {
-	global $allowedposttags;
-	return wp_kses( $data , $allowedposttags );
+	return wp_kses( $data , 'post' );
 }
 
 /**
@@ -1347,8 +1315,8 @@ function wp_kses_post($data) {
  * @param string $data Content to strip all HTML from
  * @return string Filtered content without any HTML
  */
-function wp_filter_nohtml_kses($data) {
-	return addslashes ( wp_kses(stripslashes( $data ), array()) );
+function wp_filter_nohtml_kses( $data ) {
+	return addslashes ( wp_kses( stripslashes( $data ), 'strip' ) );
 }
 
 /**
@@ -1484,3 +1452,29 @@ function safecss_filter_attr( $css, $deprecated = '' ) {
 
 	return $css;
 }
+
+/**
+ * Helper function to add global attributes to a tag in the allowed html list.
+ *
+ * @since 3.5.0
+ * @access private
+ *
+ * @param array $value An array of attributes.
+ * @return array The array of attributes with global attributes added.
+ */
+function _wp_add_global_attributes( $value ) {
+	$global_attributes = array(
+		'class' => true,
+		'id' => true,
+		'style' => true,
+		'title' => true,
+	);
+
+	if ( true === $value )
+		$value = array();
+
+	if ( is_array( $value ) )
+		return array_merge( $value, $global_attributes );
+
+	return $value;
+}