WordPress/wp-includes/kses.php
Gary Pendergast 722f25cd97 KSES: Allow the download attribute on <a> tags.
To avoid this being a vector for bypassing the filetypes that are allowed to be uploaded, this attribute is only allowed to be added without a value.

Props kalpshit, arshidkv12, welcher, peterwilsoncc, marina_wp, pento.
See #44724.


Built from https://develop.svn.wordpress.org/branches/5.0@43813


git-svn-id: http://core.svn.wordpress.org/branches/5.0@43642 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2018-10-24 01:19:39 +00:00

1923 lines
52 KiB
PHP

<?php
/**
* kses 0.2.2 - HTML/XHTML filter that only allows some elements and attributes
* Copyright (C) 2002, 2003, 2005 Ulf Harnhammar
*
* This program is free software and open source software; you can redistribute
* it and/or modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
* http://www.gnu.org/licenses/gpl.html
*
* [kses strips evil scripts!]
*
* Added wp_ prefix to avoid conflicts with existing kses users
*
* @version 0.2.2
* @copyright (C) 2002, 2003, 2005
* @author Ulf Harnhammar <http://advogato.org/person/metaur/>
*
* @package External
* @subpackage KSES
*
*/
/**
* You can override this in a plugin.
*
* The {@see 'wp_kses_allowed_html'} filter is more powerful and supplies context.
*
* `CUSTOM_TAGS` is not recommended and should be considered deprecated.
*
* @see wp_kses_allowed_html()
*
* @since 1.2.0
*/
if ( ! defined( 'CUSTOM_TAGS' ) )
define( 'CUSTOM_TAGS', false );
// Ensure that these variables are added to the global namespace
// (e.g. if using namespaces / autoload in the current PHP environment).
global $allowedposttags, $allowedtags, $allowedentitynames;
if ( ! CUSTOM_TAGS ) {
/**
* Kses global for default allowable HTML tags.
*
* Can be override by using CUSTOM_TAGS constant.
*
* @global array $allowedposttags
* @since 2.0.0
*/
$allowedposttags = array(
'address' => array(),
'a' => array(
'href' => true,
'rel' => true,
'rev' => true,
'name' => true,
'target' => true,
'download' => array(
'valueless' => 'y',
),
),
'abbr' => array(),
'acronym' => array(),
'area' => array(
'alt' => true,
'coords' => true,
'href' => true,
'nohref' => true,
'shape' => true,
'target' => true,
),
'article' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'aside' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'audio' => array(
'autoplay' => true,
'controls' => true,
'loop' => true,
'muted' => true,
'preload' => true,
'src' => true,
),
'b' => array(),
'bdo' => array(
'dir' => true,
),
'big' => array(),
'blockquote' => array(
'cite' => true,
'lang' => true,
'xml:lang' => true,
),
'br' => array(),
'button' => array(
'disabled' => true,
'name' => true,
'type' => true,
'value' => true,
),
'caption' => array(
'align' => true,
),
'cite' => array(
'dir' => true,
'lang' => true,
),
'code' => array(),
'col' => array(
'align' => true,
'char' => true,
'charoff' => true,
'span' => true,
'dir' => true,
'valign' => true,
'width' => true,
),
'colgroup' => array(
'align' => true,
'char' => true,
'charoff' => true,
'span' => true,
'valign' => true,
'width' => true,
),
'del' => array(
'datetime' => true,
),
'dd' => array(),
'dfn' => array(),
'details' => array(
'align' => true,
'dir' => true,
'lang' => true,
'open' => true,
'xml:lang' => true,
),
'div' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'dl' => array(),
'dt' => array(),
'em' => array(),
'fieldset' => array(),
'figure' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'figcaption' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'font' => array(
'color' => true,
'face' => true,
'size' => true,
),
'footer' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'form' => array(
'action' => true,
'accept' => true,
'accept-charset' => true,
'enctype' => true,
'method' => true,
'name' => true,
'target' => true,
),
'h1' => array(
'align' => true,
),
'h2' => array(
'align' => true,
),
'h3' => array(
'align' => true,
),
'h4' => array(
'align' => true,
),
'h5' => array(
'align' => true,
),
'h6' => array(
'align' => true,
),
'header' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'hgroup' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'hr' => array(
'align' => true,
'noshade' => true,
'size' => true,
'width' => true,
),
'i' => array(),
'img' => array(
'alt' => true,
'align' => true,
'border' => true,
'height' => true,
'hspace' => true,
'longdesc' => true,
'vspace' => true,
'src' => true,
'usemap' => true,
'width' => true,
),
'ins' => array(
'datetime' => true,
'cite' => true,
),
'kbd' => array(),
'label' => array(
'for' => true,
),
'legend' => array(
'align' => true,
),
'li' => array(
'align' => true,
'value' => true,
),
'map' => array(
'name' => true,
),
'mark' => array(),
'menu' => array(
'type' => true,
),
'nav' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'p' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'pre' => array(
'width' => true,
),
'q' => array(
'cite' => true,
),
's' => array(),
'samp' => array(),
'span' => array(
'dir' => true,
'align' => true,
'lang' => true,
'xml:lang' => true,
),
'section' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'small' => array(),
'strike' => array(),
'strong' => array(),
'sub' => array(),
'summary' => array(
'align' => true,
'dir' => true,
'lang' => true,
'xml:lang' => true,
),
'sup' => array(),
'table' => array(
'align' => true,
'bgcolor' => true,
'border' => true,
'cellpadding' => true,
'cellspacing' => true,
'dir' => true,
'rules' => true,
'summary' => true,
'width' => true,
),
'tbody' => array(
'align' => true,
'char' => true,
'charoff' => true,
'valign' => true,
),
'td' => array(
'abbr' => true,
'align' => true,
'axis' => true,
'bgcolor' => true,
'char' => true,
'charoff' => true,
'colspan' => true,
'dir' => true,
'headers' => true,
'height' => true,
'nowrap' => true,
'rowspan' => true,
'scope' => true,
'valign' => true,
'width' => true,
),
'textarea' => array(
'cols' => true,
'rows' => true,
'disabled' => true,
'name' => true,
'readonly' => true,
),
'tfoot' => array(
'align' => true,
'char' => true,
'charoff' => true,
'valign' => true,
),
'th' => array(
'abbr' => true,
'align' => true,
'axis' => true,
'bgcolor' => true,
'char' => true,
'charoff' => true,
'colspan' => true,
'headers' => true,
'height' => true,
'nowrap' => true,
'rowspan' => true,
'scope' => true,
'valign' => true,
'width' => true,
),
'thead' => array(
'align' => true,
'char' => true,
'charoff' => true,
'valign' => true,
),
'title' => array(),
'tr' => array(
'align' => true,
'bgcolor' => true,
'char' => true,
'charoff' => true,
'valign' => true,
),
'track' => array(
'default' => true,
'kind' => true,
'label' => true,
'src' => true,
'srclang' => true,
),
'tt' => array(),
'u' => array(),
'ul' => array(
'type' => true,
),
'ol' => array(
'start' => true,
'type' => true,
'reversed' => true,
),
'var' => array(),
'video' => array(
'autoplay' => true,
'controls' => true,
'height' => true,
'loop' => true,
'muted' => true,
'poster' => true,
'preload' => true,
'src' => true,
'width' => true,
),
);
/**
* Kses allowed HTML elements.
*
* @global array $allowedtags
* @since 1.0.0
*/
$allowedtags = array(
'a' => array(
'href' => true,
'title' => true,
),
'abbr' => array(
'title' => true,
),
'acronym' => array(
'title' => true,
),
'b' => array(),
'blockquote' => array(
'cite' => true,
),
'cite' => array(),
'code' => array(),
'del' => array(
'datetime' => true,
),
'em' => array(),
'i' => array(),
'q' => array(
'cite' => true,
),
's' => array(),
'strike' => array(),
'strong' => array(),
);
$allowedentitynames = array(
'nbsp', 'iexcl', 'cent', 'pound', 'curren', 'yen',
'brvbar', 'sect', 'uml', 'copy', 'ordf', 'laquo',
'not', 'shy', 'reg', 'macr', 'deg', 'plusmn',
'acute', 'micro', 'para', 'middot', 'cedil', 'ordm',
'raquo', 'iquest', 'Agrave', 'Aacute', 'Acirc', 'Atilde',
'Auml', 'Aring', 'AElig', 'Ccedil', 'Egrave', 'Eacute',
'Ecirc', 'Euml', 'Igrave', 'Iacute', 'Icirc', 'Iuml',
'ETH', 'Ntilde', 'Ograve', 'Oacute', 'Ocirc', 'Otilde',
'Ouml', 'times', 'Oslash', 'Ugrave', 'Uacute', 'Ucirc',
'Uuml', 'Yacute', 'THORN', 'szlig', 'agrave', 'aacute',
'acirc', 'atilde', 'auml', 'aring', 'aelig', 'ccedil',
'egrave', 'eacute', 'ecirc', 'euml', 'igrave', 'iacute',
'icirc', 'iuml', 'eth', 'ntilde', 'ograve', 'oacute',
'ocirc', 'otilde', 'ouml', 'divide', 'oslash', 'ugrave',
'uacute', 'ucirc', 'uuml', 'yacute', 'thorn', 'yuml',
'quot', 'amp', 'lt', 'gt', 'apos', 'OElig',
'oelig', 'Scaron', 'scaron', 'Yuml', 'circ', 'tilde',
'ensp', 'emsp', 'thinsp', 'zwnj', 'zwj', 'lrm',
'rlm', 'ndash', 'mdash', 'lsquo', 'rsquo', 'sbquo',
'ldquo', 'rdquo', 'bdquo', 'dagger', 'Dagger', 'permil',
'lsaquo', 'rsaquo', 'euro', 'fnof', 'Alpha', 'Beta',
'Gamma', 'Delta', 'Epsilon', 'Zeta', 'Eta', 'Theta',
'Iota', 'Kappa', 'Lambda', 'Mu', 'Nu', 'Xi',
'Omicron', 'Pi', 'Rho', 'Sigma', 'Tau', 'Upsilon',
'Phi', 'Chi', 'Psi', 'Omega', 'alpha', 'beta',
'gamma', 'delta', 'epsilon', 'zeta', 'eta', 'theta',
'iota', 'kappa', 'lambda', 'mu', 'nu', 'xi',
'omicron', 'pi', 'rho', 'sigmaf', 'sigma', 'tau',
'upsilon', 'phi', 'chi', 'psi', 'omega', 'thetasym',
'upsih', 'piv', 'bull', 'hellip', 'prime', 'Prime',
'oline', 'frasl', 'weierp', 'image', 'real', 'trade',
'alefsym', 'larr', 'uarr', 'rarr', 'darr', 'harr',
'crarr', 'lArr', 'uArr', 'rArr', 'dArr', 'hArr',
'forall', 'part', 'exist', 'empty', 'nabla', 'isin',
'notin', 'ni', 'prod', 'sum', 'minus', 'lowast',
'radic', 'prop', 'infin', 'ang', 'and', 'or',
'cap', 'cup', 'int', 'sim', 'cong', 'asymp',
'ne', 'equiv', 'le', 'ge', 'sub', 'sup',
'nsub', 'sube', 'supe', 'oplus', 'otimes', 'perp',
'sdot', 'lceil', 'rceil', 'lfloor', 'rfloor', 'lang',
'rang', 'loz', 'spades', 'clubs', 'hearts', 'diams',
'sup1', 'sup2', 'sup3', 'frac14', 'frac12', 'frac34',
'there4',
);
$allowedposttags = array_map( '_wp_add_global_attributes', $allowedposttags );
} else {
$allowedtags = wp_kses_array_lc( $allowedtags );
$allowedposttags = wp_kses_array_lc( $allowedposttags );
}
/**
* Filters content and keeps only allowable HTML elements.
*
* This function makes sure that only the allowed HTML element names, attribute
* names and attribute values plus only sane HTML entities will occur in
* $string. You have to remove any slashes from PHP's magic quotes before you
* call this function.
*
* The default allowed protocols are 'http', 'https', 'ftp', 'mailto', 'news',
* 'irc', 'gopher', 'nntp', 'feed', 'telnet, 'mms', 'rtsp' and 'svn'. This
* covers all common link protocols, except for 'javascript' which should not
* be allowed for untrusted users.
*
* @since 1.0.0
*
* @param string $string Content to filter through kses
* @param array $allowed_html List of allowed HTML elements
* @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() ) {
if ( empty( $allowed_protocols ) )
$allowed_protocols = wp_allowed_protocols();
$string = wp_kses_no_null( $string, array( 'slash_zero' => 'keep' ) );
$string = wp_kses_normalize_entities($string);
$string = wp_kses_hook($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);
}
/**
* Filters one attribute only and ensures its value is allowed.
*
* This function has the advantage of being more secure than esc_attr() and can
* escape data in some situations where wp_kses() must strip the whole attribute.
*
* @since 4.2.3
*
* @param string $string The 'whole' attribute, including name and value.
* @param string $element The element name to which the attribute belongs.
* @return string Filtered attribute.
*/
function wp_kses_one_attr( $string, $element ) {
$uris = array('xmlns', 'profile', 'href', 'src', 'cite', 'classid', 'codebase', 'data', 'usemap', 'longdesc', 'action');
$allowed_html = wp_kses_allowed_html( 'post' );
$allowed_protocols = wp_allowed_protocols();
$string = wp_kses_no_null( $string, array( 'slash_zero' => 'keep' ) );
// Preserve leading and trailing whitespace.
$matches = array();
preg_match('/^\s*/', $string, $matches);
$lead = $matches[0];
preg_match('/\s*$/', $string, $matches);
$trail = $matches[0];
if ( empty( $trail ) ) {
$string = substr( $string, strlen( $lead ) );
} else {
$string = substr( $string, strlen( $lead ), -strlen( $trail ) );
}
// Parse attribute name and value from input.
$split = preg_split( '/\s*=\s*/', $string, 2 );
$name = $split[0];
if ( count( $split ) == 2 ) {
$value = $split[1];
// Remove quotes surrounding $value.
// Also guarantee correct quoting in $string for this one attribute.
if ( '' == $value ) {
$quote = '';
} else {
$quote = $value[0];
}
if ( '"' == $quote || "'" == $quote ) {
if ( substr( $value, -1 ) != $quote ) {
return '';
}
$value = substr( $value, 1, -1 );
} else {
$quote = '"';
}
// Sanitize quotes, angle braces, and entities.
$value = esc_attr( $value );
// Sanitize URI values.
if ( in_array( strtolower( $name ), $uris ) ) {
$value = wp_kses_bad_protocol( $value, $allowed_protocols );
}
$string = "$name=$quote$value$quote";
$vless = 'n';
} else {
$value = '';
$vless = 'y';
}
// Sanitize attribute by name.
wp_kses_attr_check( $name, $value, $string, $vless, $element, $allowed_html );
// Restore whitespace.
return $lead . $string . $trail;
}
/**
* Return a list of allowed tags and attributes for a given context.
*
* @since 3.5.0
*
* @global array $allowedposttags
* @global array $allowedtags
* @global array $allowedentitynames
*
* @param string|array $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 ) ) {
/**
* Filters HTML elements allowed for a given context.
*
* @since 3.5.0
*
* @param array $context Context to judge allowed tags by.
* @param string $context_type Context type (explicit).
*/
return apply_filters( 'wp_kses_allowed_html', $context, 'explicit' );
}
switch ( $context ) {
case 'post':
/** This filter is documented in wp-includes/kses.php */
return apply_filters( 'wp_kses_allowed_html', $allowedposttags, $context );
case 'user_description':
case 'pre_user_description':
$tags = $allowedtags;
$tags['a']['rel'] = true;
/** This filter is documented in wp-includes/kses.php */
return apply_filters( 'wp_kses_allowed_html', $tags, $context );
case 'strip':
/** This filter is documented in wp-includes/kses.php */
return apply_filters( 'wp_kses_allowed_html', array(), $context );
case 'entities':
/** This filter is documented in wp-includes/kses.php */
return apply_filters( 'wp_kses_allowed_html', $allowedentitynames, $context);
case 'data':
default:
/** This filter is documented in wp-includes/kses.php */
return apply_filters( 'wp_kses_allowed_html', $allowedtags, $context );
}
}
/**
* You add any kses hooks here.
*
* There is currently only one kses WordPress hook, {@see 'pre_kses'}, and it is called here.
* All parameters are passed to the hooks and expected to receive a string.
*
* @since 1.0.0
*
* @param string $string Content to filter through kses
* @param array $allowed_html List of allowed HTML elements
* @param array $allowed_protocols Allowed protocol in links
* @return string Filtered content through {@see 'pre_kses'} hook.
*/
function wp_kses_hook( $string, $allowed_html, $allowed_protocols ) {
/**
* Filters content to be run through kses.
*
* @since 2.3.0
*
* @param string $string Content to run through kses.
* @param array $allowed_html Allowed HTML elements.
* @param array $allowed_protocols Allowed protocol in links.
*/
return apply_filters( 'pre_kses', $string, $allowed_html, $allowed_protocols );
}
/**
* This function returns kses' version number.
*
* @since 1.0.0
*
* @return string KSES Version Number
*/
function wp_kses_version() {
return '0.2.2';
}
/**
* Searches for HTML tags, no matter how malformed.
*
* It also matches stray ">" characters.
*
* @since 1.0.0
*
* @global array $pass_allowed_html
* @global array $pass_allowed_protocols
*
* @param string $string Content to filter
* @param array $allowed_html Allowed HTML elements
* @param array $allowed_protocols Allowed protocols to keep
* @return string Content with fixed HTML tags
*/
function wp_kses_split( $string, $allowed_html, $allowed_protocols ) {
global $pass_allowed_html, $pass_allowed_protocols;
$pass_allowed_html = $allowed_html;
$pass_allowed_protocols = $allowed_protocols;
return preg_replace_callback( '%(<!--.*?(-->|$))|(<[^>]*(>|$)|>)%', '_wp_kses_split_callback', $string );
}
/**
* Callback for wp_kses_split.
*
* @since 3.1.0
* @access private
*
* @global array $pass_allowed_html
* @global array $pass_allowed_protocols
*
* @return string
*/
function _wp_kses_split_callback( $match ) {
global $pass_allowed_html, $pass_allowed_protocols;
return wp_kses_split2( $match[0], $pass_allowed_html, $pass_allowed_protocols );
}
/**
* Callback for wp_kses_split for fixing malformed HTML tags.
*
* This function does a lot of work. It rejects some very malformed things like
* <:::>. It returns an empty string, if the element isn't allowed (look ma, no
* strip_tags()!). Otherwise it splits the tag into an element and an attribute
* list.
*
* After the tag is split into an element and an attribute list, it is run
* through another filter which will remove illegal attributes and once that is
* completed, will be returned.
*
* @access private
* @since 1.0.0
*
* @param string $string Content to filter
* @param array $allowed_html Allowed HTML elements
* @param array $allowed_protocols Allowed protocols to keep
* @return string Fixed HTML element
*/
function wp_kses_split2($string, $allowed_html, $allowed_protocols) {
$string = wp_kses_stripslashes($string);
if (substr($string, 0, 1) != '<')
return '&gt;';
// It matched a ">" character
if ( '<!--' == substr( $string, 0, 4 ) ) {
$string = str_replace( array('<!--', '-->'), '', $string );
while ( $string != ($newstring = wp_kses($string, $allowed_html, $allowed_protocols)) )
$string = $newstring;
if ( $string == '' )
return '';
// prevent multiple dashes in comments
$string = preg_replace('/--+/', '-', $string);
// prevent three dashes closing a comment
$string = preg_replace('/-$/', '', $string);
return "<!--{$string}-->";
}
// Allow HTML comments
if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9-]+)([^>]*)>?$%', $string, $matches))
return '';
// It's seriously malformed
$slash = trim($matches[1]);
$elem = $matches[2];
$attrlist = $matches[3];
if ( ! is_array( $allowed_html ) )
$allowed_html = wp_kses_allowed_html( $allowed_html );
if ( ! isset($allowed_html[strtolower($elem)]) )
return '';
// They are using a not allowed HTML element
if ($slash != '')
return "</$elem>";
// No attributes are allowed for closing elements
return wp_kses_attr( $elem, $attrlist, $allowed_html, $allowed_protocols );
}
/**
* Removes all attributes, if none are allowed for this element.
*
* If some are allowed it calls wp_kses_hair() to split them further, and then
* it builds up new HTML code from the data that kses_hair() returns. It also
* removes "<" and ">" characters, if there are any left. One more thing it does
* is to check if the tag has a closing XHTML slash, and if it does, it puts one
* in the returned code as well.
*
* @since 1.0.0
*
* @param string $element HTML element/tag
* @param string $attr HTML attributes from HTML element to closing HTML element tag
* @param array $allowed_html Allowed HTML elements
* @param array $allowed_protocols Allowed protocols to keep
* @return string Sanitized HTML element
*/
function wp_kses_attr($element, $attr, $allowed_html, $allowed_protocols) {
if ( ! is_array( $allowed_html ) )
$allowed_html = wp_kses_allowed_html( $allowed_html );
// Is there a closing XHTML slash at the end of the attributes?
$xhtml_slash = '';
if (preg_match('%\s*/\s*$%', $attr))
$xhtml_slash = ' /';
// Are any attributes allowed at all for this element?
$element_low = strtolower( $element );
if ( empty( $allowed_html[ $element_low ] ) || true === $allowed_html[ $element_low ] ) {
return "<$element$xhtml_slash>";
}
// Split it
$attrarr = wp_kses_hair($attr, $allowed_protocols);
// Go through $attrarr, and save the allowed attributes for this element
// in $attr2
$attr2 = '';
foreach ( $attrarr as $arreach ) {
if ( wp_kses_attr_check( $arreach['name'], $arreach['value'], $arreach['whole'], $arreach['vless'], $element, $allowed_html ) ) {
$attr2 .= ' '.$arreach['whole'];
}
}
// Remove any "<" or ">" characters
$attr2 = preg_replace('/[<>]/', '', $attr2);
return "<$element$attr2$xhtml_slash>";
}
/**
* Determine whether an attribute is allowed.
*
* @since 4.2.3
* @since 5.0.0 Add support for `data-*` wildcard attributes.
*
* @param string $name The attribute name. Returns empty string when not allowed.
* @param string $value The attribute value. Returns a filtered value.
* @param string $whole The name=value input. Returns filtered input.
* @param string $vless 'y' when attribute like "enabled", otherwise 'n'.
* @param string $element The name of the element to which this attribute belongs.
* @param array $allowed_html The full list of allowed elements and attributes.
* @return bool Is the attribute allowed?
*/
function wp_kses_attr_check( &$name, &$value, &$whole, $vless, $element, $allowed_html ) {
$allowed_attr = $allowed_html[ strtolower( $element ) ];
$name_low = strtolower( $name );
if ( ! isset( $allowed_attr[$name_low] ) || '' == $allowed_attr[$name_low] ) {
/*
* Allow `data-*` attributes.
*
* When specifying `$allowed_html`, the attribute name should be set as
* `data-*` (not to be mixed with the HTML 4.0 `data` attribute, see
* https://www.w3.org/TR/html40/struct/objects.html#adef-data).
*
* Note: the attribute name should only contain `A-Za-z0-9_-` chars,
* double hyphens `--` are not accepted by WordPress.
*/
if ( strpos( $name_low, 'data-' ) === 0 && ! empty( $allowed_attr['data-*'] ) && preg_match( '/^data(?:-[a-z0-9_]+)+$/', $name_low, $match ) ) {
/*
* Add the whole attribute name to the allowed attributes and set any restrictions
* for the `data-*` attribute values for the current element.
*/
$allowed_attr[ $match[0] ] = $allowed_attr['data-*'];
} else {
$name = $value = $whole = '';
return false;
}
}
if ( 'style' == $name_low ) {
$new_value = safecss_filter_attr( $value );
if ( empty( $new_value ) ) {
$name = $value = $whole = '';
return false;
}
$whole = str_replace( $value, $new_value, $whole );
$value = $new_value;
}
if ( is_array( $allowed_attr[ $name_low ] ) ) {
// there are some checks
foreach ( $allowed_attr[$name_low] as $currkey => $currval ) {
if ( ! wp_kses_check_attr_val( $value, $vless, $currkey, $currval ) ) {
$name = $value = $whole = '';
return false;
}
}
}
return true;
}
/**
* Builds an attribute list from string containing attributes.
*
* This function does a lot of work. It parses an attribute list into an array
* with attribute data, and tries to do the right thing even if it gets weird
* input. It will add quotes around attribute values that don't have any quotes
* or apostrophes around them, to make it easier to produce HTML code that will
* conform to W3C's HTML specification. It will also remove bad URL protocols
* from attribute values. It also reduces duplicate attributes by using the
* attribute defined first (foo='bar' foo='baz' will result in foo='bar').
*
* @since 1.0.0
*
* @param string $attr Attribute list from HTML element to closing HTML element tag
* @param array $allowed_protocols Allowed protocols to keep
* @return array List of attributes after parsing
*/
function wp_kses_hair($attr, $allowed_protocols) {
$attrarr = array();
$mode = 0;
$attrname = '';
$uris = array('xmlns', 'profile', 'href', 'src', 'cite', 'classid', 'codebase', 'data', 'usemap', 'longdesc', 'action');
// Loop through the whole attribute list
while (strlen($attr) != 0) {
$working = 0; // Was the last operation successful?
switch ($mode) {
case 0 : // attribute name, href for instance
if ( preg_match('/^([-a-zA-Z:]+)/', $attr, $match ) ) {
$attrname = $match[1];
$working = $mode = 1;
$attr = preg_replace( '/^[-a-zA-Z:]+/', '', $attr );
}
break;
case 1 : // equals sign or valueless ("selected")
if (preg_match('/^\s*=\s*/', $attr)) // equals sign
{
$working = 1;
$mode = 2;
$attr = preg_replace('/^\s*=\s*/', '', $attr);
break;
}
if (preg_match('/^\s+/', $attr)) // valueless
{
$working = 1;
$mode = 0;
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y');
}
$attr = preg_replace('/^\s+/', '', $attr);
}
break;
case 2 : // attribute value, a URL after href= for instance
if (preg_match('%^"([^"]*)"(\s+|/?$)%', $attr, $match))
// "value"
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n');
}
$working = 1;
$mode = 0;
$attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr);
break;
}
if (preg_match("%^'([^']*)'(\s+|/?$)%", $attr, $match))
// 'value'
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname='$thisval'", 'vless' => 'n');
}
$working = 1;
$mode = 0;
$attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr);
break;
}
if (preg_match("%^([^\s\"']+)(\s+|/?$)%", $attr, $match))
// value
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n');
}
// We add quotes to conform to W3C's HTML spec.
$working = 1;
$mode = 0;
$attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
}
break;
} // switch
if ($working == 0) // not well formed, remove and try again
{
$attr = wp_kses_html_error($attr);
$mode = 0;
}
} // while
if ($mode == 1 && false === array_key_exists($attrname, $attrarr))
// special case, for when the attribute list ends with a valueless
// attribute like "selected"
$attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y');
return $attrarr;
}
/**
* Finds all attributes of an HTML element.
*
* Does not modify input. May return "evil" output.
*
* Based on wp_kses_split2() and wp_kses_attr()
*
* @since 4.2.3
*
* @param string $element HTML element/tag
* @return array|bool List of attributes found in $element. Returns false on failure.
*/
function wp_kses_attr_parse( $element ) {
$valid = preg_match('%^(<\s*)(/\s*)?([a-zA-Z0-9]+\s*)([^>]*)(>?)$%', $element, $matches);
if ( 1 !== $valid ) {
return false;
}
$begin = $matches[1];
$slash = $matches[2];
$elname = $matches[3];
$attr = $matches[4];
$end = $matches[5];
if ( '' !== $slash ) {
// Closing elements do not get parsed.
return false;
}
// Is there a closing XHTML slash at the end of the attributes?
if ( 1 === preg_match( '%\s*/\s*$%', $attr, $matches ) ) {
$xhtml_slash = $matches[0];
$attr = substr( $attr, 0, -strlen( $xhtml_slash ) );
} else {
$xhtml_slash = '';
}
// Split it
$attrarr = wp_kses_hair_parse( $attr );
if ( false === $attrarr ) {
return false;
}
// Make sure all input is returned by adding front and back matter.
array_unshift( $attrarr, $begin . $slash . $elname );
array_push( $attrarr, $xhtml_slash . $end );
return $attrarr;
}
/**
* Builds an attribute list from string containing attributes.
*
* Does not modify input. May return "evil" output.
* In case of unexpected input, returns false instead of stripping things.
*
* Based on wp_kses_hair() but does not return a multi-dimensional array.
*
* @since 4.2.3
*
* @param string $attr Attribute list from HTML element to closing HTML element tag
* @return array|bool List of attributes found in $attr. Returns false on failure.
*/
function wp_kses_hair_parse( $attr ) {
if ( '' === $attr ) {
return array();
}
$regex =
'(?:'
. '[-a-zA-Z:]+' // Attribute name.
. '|'
. '\[\[?[^\[\]]+\]\]?' // Shortcode in the name position implies unfiltered_html.
. ')'
. '(?:' // Attribute value.
. '\s*=\s*' // All values begin with '='
. '(?:'
. '"[^"]*"' // Double-quoted
. '|'
. "'[^']*'" // Single-quoted
. '|'
. '[^\s"\']+' // Non-quoted
. '(?:\s|$)' // Must have a space
. ')'
. '|'
. '(?:\s|$)' // If attribute has no value, space is required.
. ')'
. '\s*'; // Trailing space is optional except as mentioned above.
// Although it is possible to reduce this procedure to a single regexp,
// we must run that regexp twice to get exactly the expected result.
$validation = "%^($regex)+$%";
$extraction = "%$regex%";
if ( 1 === preg_match( $validation, $attr ) ) {
preg_match_all( $extraction, $attr, $attrarr );
return $attrarr[0];
} else {
return false;
}
}
/**
* Performs different checks for attribute values.
*
* The currently implemented checks are "maxlen", "minlen", "maxval", "minval"
* and "valueless".
*
* @since 1.0.0
*
* @param string $value Attribute value
* @param string $vless Whether the value is valueless. Use 'y' or 'n'
* @param string $checkname What $checkvalue is checking for.
* @param mixed $checkvalue What constraint the value should pass
* @return bool Whether check passes
*/
function wp_kses_check_attr_val($value, $vless, $checkname, $checkvalue) {
$ok = true;
switch (strtolower($checkname)) {
case 'maxlen' :
// The maxlen check makes sure that the attribute value has a length not
// greater than the given value. This can be used to avoid Buffer Overflows
// in WWW clients and various Internet servers.
if (strlen($value) > $checkvalue)
$ok = false;
break;
case 'minlen' :
// The minlen check makes sure that the attribute value has a length not
// smaller than the given value.
if (strlen($value) < $checkvalue)
$ok = false;
break;
case 'maxval' :
// The maxval check does two things: it checks that the attribute value is
// an integer from 0 and up, without an excessive amount of zeroes or
// whitespace (to avoid Buffer Overflows). It also checks that the attribute
// value is not greater than the given value.
// This check can be used to avoid Denial of Service attacks.
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
$ok = false;
if ($value > $checkvalue)
$ok = false;
break;
case 'minval' :
// The minval check makes sure that the attribute value is a positive integer,
// and that it is not smaller than the given value.
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
$ok = false;
if ($value < $checkvalue)
$ok = false;
break;
case 'valueless' :
// The valueless check makes sure if the attribute has a value
// (like <a href="blah">) or not (<option selected>). If the given value
// is a "y" or a "Y", the attribute must not have a value.
// If the given value is an "n" or an "N", the attribute must have one.
if (strtolower($checkvalue) != $vless)
$ok = false;
break;
} // switch
return $ok;
}
/**
* Sanitize string from bad protocols.
*
* This function removes all non-allowed protocols from the beginning of
* $string. It ignores whitespace and the case of the letters, and it does
* understand HTML entities. It does its work in a while loop, so it won't be
* fooled by a string like "javascript:javascript:alert(57)".
*
* @since 1.0.0
*
* @param string $string Content to filter bad protocols from
* @param array $allowed_protocols Allowed protocols to keep
* @return string Filtered content
*/
function wp_kses_bad_protocol($string, $allowed_protocols) {
$string = wp_kses_no_null($string);
$iterations = 0;
do {
$original_string = $string;
$string = wp_kses_bad_protocol_once($string, $allowed_protocols);
} while ( $original_string != $string && ++$iterations < 6 );
if ( $original_string != $string )
return '';
return $string;
}
/**
* Removes any invalid control characters in $string.
*
* Also removes any instance of the '\0' string.
*
* @since 1.0.0
*
* @param string $string
* @param array $options Set 'slash_zero' => 'keep' when '\0' is allowed. Default is 'remove'.
* @return string
*/
function wp_kses_no_null( $string, $options = null ) {
if ( ! isset( $options['slash_zero'] ) ) {
$options = array( 'slash_zero' => 'remove' );
}
$string = preg_replace( '/[\x00-\x08\x0B\x0C\x0E-\x1F]/', '', $string );
if ( 'remove' == $options['slash_zero'] ) {
$string = preg_replace( '/\\\\+0+/', '', $string );
}
return $string;
}
/**
* Strips slashes from in front of quotes.
*
* This function changes the character sequence \" to just ". It leaves all
* other slashes alone. It's really weird, but the quoting from
* preg_replace(//e) seems to require this.
*
* @since 1.0.0
*
* @param string $string String to strip slashes
* @return string Fixed string with quoted slashes
*/
function wp_kses_stripslashes($string) {
return preg_replace('%\\\\"%', '"', $string);
}
/**
* Goes through an array and changes the keys to all lower case.
*
* @since 1.0.0
*
* @param array $inarray Unfiltered array
* @return array Fixed array with all lowercase keys
*/
function wp_kses_array_lc($inarray) {
$outarray = array ();
foreach ( (array) $inarray as $inkey => $inval) {
$outkey = strtolower($inkey);
$outarray[$outkey] = array ();
foreach ( (array) $inval as $inkey2 => $inval2) {
$outkey2 = strtolower($inkey2);
$outarray[$outkey][$outkey2] = $inval2;
} // foreach $inval
} // foreach $inarray
return $outarray;
}
/**
* Handles parsing errors in wp_kses_hair().
*
* The general plan is to remove everything to and including some whitespace,
* but it deals with quotes and apostrophes as well.
*
* @since 1.0.0
*
* @param string $string
* @return string
*/
function wp_kses_html_error($string) {
return preg_replace('/^("[^"]*("|$)|\'[^\']*(\'|$)|\S)*\s*/', '', $string);
}
/**
* Sanitizes content from bad protocols and other characters.
*
* This function searches for URL protocols at the beginning of $string, while
* handling whitespace and HTML entities.
*
* @since 1.0.0
*
* @param string $string Content to check for bad protocols
* @param string $allowed_protocols Allowed protocols
* @return string Sanitized content
*/
function wp_kses_bad_protocol_once($string, $allowed_protocols, $count = 1 ) {
$string2 = preg_split( '/:|&#0*58;|&#x0*3a;/i', $string, 2 );
if ( isset($string2[1]) && ! preg_match('%/\?%', $string2[0]) ) {
$string = trim( $string2[1] );
$protocol = wp_kses_bad_protocol_once2( $string2[0], $allowed_protocols );
if ( 'feed:' == $protocol ) {
if ( $count > 2 )
return '';
$string = wp_kses_bad_protocol_once( $string, $allowed_protocols, ++$count );
if ( empty( $string ) )
return $string;
}
$string = $protocol . $string;
}
return $string;
}
/**
* Callback for wp_kses_bad_protocol_once() regular expression.
*
* This function processes URL protocols, checks to see if they're in the
* whitelist or not, and returns different data depending on the answer.
*
* @access private
* @since 1.0.0
*
* @param string $string URI scheme to check against the whitelist
* @param string $allowed_protocols Allowed protocols
* @return string Sanitized content
*/
function wp_kses_bad_protocol_once2( $string, $allowed_protocols ) {
$string2 = wp_kses_decode_entities($string);
$string2 = preg_replace('/\s/', '', $string2);
$string2 = wp_kses_no_null($string2);
$string2 = strtolower($string2);
$allowed = false;
foreach ( (array) $allowed_protocols as $one_protocol )
if ( strtolower($one_protocol) == $string2 ) {
$allowed = true;
break;
}
if ($allowed)
return "$string2:";
else
return '';
}
/**
* Converts and fixes HTML entities.
*
* This function normalizes HTML entities. It will convert `AT&T` to the correct
* `AT&amp;T`, `&#00058;` to `&#58;`, `&#XYZZY;` to `&amp;#XYZZY;` and so on.
*
* @since 1.0.0
*
* @param string $string Content to normalize entities
* @return string Content with normalized entities
*/
function wp_kses_normalize_entities($string) {
// Disarm all entities by converting & to &amp;
$string = str_replace('&', '&amp;', $string);
// Change back the allowed entities in our entity whitelist
$string = preg_replace_callback('/&amp;([A-Za-z]{2,8}[0-9]{0,2});/', 'wp_kses_named_entities', $string);
$string = preg_replace_callback('/&amp;#(0*[0-9]{1,7});/', 'wp_kses_normalize_entities2', $string);
$string = preg_replace_callback('/&amp;#[Xx](0*[0-9A-Fa-f]{1,6});/', 'wp_kses_normalize_entities3', $string);
return $string;
}
/**
* Callback for wp_kses_normalize_entities() regular expression.
*
* This function only accepts valid named entity references, which are finite,
* case-sensitive, and highly scrutinized by HTML and XML validators.
*
* @since 3.0.0
*
* @global array $allowedentitynames
*
* @param array $matches preg_replace_callback() matches array
* @return string Correctly encoded entity
*/
function wp_kses_named_entities($matches) {
global $allowedentitynames;
if ( empty($matches[1]) )
return '';
$i = $matches[1];
return ( ! in_array( $i, $allowedentitynames ) ) ? "&amp;$i;" : "&$i;";
}
/**
* Callback for wp_kses_normalize_entities() regular expression.
*
* This function helps wp_kses_normalize_entities() to only accept 16-bit
* values and nothing more for `&#number;` entities.
*
* @access private
* @since 1.0.0
*
* @param array $matches preg_replace_callback() matches array
* @return string Correctly encoded entity
*/
function wp_kses_normalize_entities2($matches) {
if ( empty($matches[1]) )
return '';
$i = $matches[1];
if (valid_unicode($i)) {
$i = str_pad(ltrim($i,'0'), 3, '0', STR_PAD_LEFT);
$i = "&#$i;";
} else {
$i = "&amp;#$i;";
}
return $i;
}
/**
* Callback for wp_kses_normalize_entities() for regular expression.
*
* This function helps wp_kses_normalize_entities() to only accept valid Unicode
* numeric entities in hex form.
*
* @since 2.7.0
* @access private
*
* @param array $matches preg_replace_callback() matches array
* @return string Correctly encoded entity
*/
function wp_kses_normalize_entities3($matches) {
if ( empty($matches[1]) )
return '';
$hexchars = $matches[1];
return ( ! valid_unicode( hexdec( $hexchars ) ) ) ? "&amp;#x$hexchars;" : '&#x'.ltrim($hexchars,'0').';';
}
/**
* Helper function to determine if a Unicode value is valid.
*
* @since 2.7.0
*
* @param int $i Unicode value
* @return bool True if the value was a valid Unicode number
*/
function valid_unicode($i) {
return ( $i == 0x9 || $i == 0xa || $i == 0xd ||
($i >= 0x20 && $i <= 0xd7ff) ||
($i >= 0xe000 && $i <= 0xfffd) ||
($i >= 0x10000 && $i <= 0x10ffff) );
}
/**
* Convert all entities to their character counterparts.
*
* This function decodes numeric HTML entities (`&#65;` and `&#x41;`).
* It doesn't do anything with other entities like &auml;, but we don't
* need them in the URL protocol whitelisting system anyway.
*
* @since 1.0.0
*
* @param string $string Content to change entities
* @return string Content after decoded entities
*/
function wp_kses_decode_entities($string) {
$string = preg_replace_callback('/&#([0-9]+);/', '_wp_kses_decode_entities_chr', $string);
$string = preg_replace_callback('/&#[Xx]([0-9A-Fa-f]+);/', '_wp_kses_decode_entities_chr_hexdec', $string);
return $string;
}
/**
* Regex callback for wp_kses_decode_entities()
*
* @since 2.9.0
*
* @param array $match preg match
* @return string
*/
function _wp_kses_decode_entities_chr( $match ) {
return chr( $match[1] );
}
/**
* Regex callback for wp_kses_decode_entities()
*
* @since 2.9.0
*
* @param array $match preg match
* @return string
*/
function _wp_kses_decode_entities_chr_hexdec( $match ) {
return chr( hexdec( $match[1] ) );
}
/**
* Sanitize content with allowed HTML Kses rules.
*
* @since 1.0.0
*
* @param string $data Content to filter, expected to be escaped with slashes
* @return string Filtered content
*/
function wp_filter_kses( $data ) {
return addslashes( wp_kses( stripslashes( $data ), current_filter() ) );
}
/**
* Sanitize content with allowed HTML Kses rules.
*
* @since 2.9.0
*
* @param string $data Content to filter, expected to not be escaped
* @return string Filtered content
*/
function wp_kses_data( $data ) {
return wp_kses( $data, current_filter() );
}
/**
* Sanitize content for allowed HTML tags for post content.
*
* Post content refers to the page contents of the 'post' type and not $_POST
* data from forms.
*
* @since 2.0.0
*
* @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 ) {
return addslashes( wp_kses( stripslashes( $data ), 'post' ) );
}
/**
* Sanitize content for allowed HTML tags for post content.
*
* Post content refers to the page contents of the 'post' type and not $_POST
* data from forms.
*
* @since 2.9.0
*
* @param string $data Post content to filter
* @return string Filtered post content with allowed HTML tags and attributes intact.
*/
function wp_kses_post( $data ) {
return wp_kses( $data, 'post' );
}
/**
* Navigates through an array, object, or scalar, and sanitizes content for
* allowed HTML tags for post content.
*
* @since 4.4.2
*
* @see map_deep()
*
* @param mixed $data The array, object, or scalar value to inspect.
* @return mixed The filtered content.
*/
function wp_kses_post_deep( $data ) {
return map_deep( $data, 'wp_kses_post' );
}
/**
* Strips all of the HTML in the content.
*
* @since 2.1.0
*
* @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 ), 'strip' ) );
}
/**
* Adds all Kses input form content filters.
*
* All hooks have default priority. The wp_filter_kses() function is added to
* the 'pre_comment_content' and 'title_save_pre' hooks.
*
* The wp_filter_post_kses() function is added to the 'content_save_pre',
* 'excerpt_save_pre', and 'content_filtered_save_pre' hooks.
*
* @since 2.0.0
*/
function kses_init_filters() {
// Normal filtering
add_filter('title_save_pre', 'wp_filter_kses');
// Comment filtering
if ( current_user_can( 'unfiltered_html' ) )
add_filter( 'pre_comment_content', 'wp_filter_post_kses' );
else
add_filter( 'pre_comment_content', 'wp_filter_kses' );
// Post filtering
add_filter('content_save_pre', 'wp_filter_post_kses');
add_filter('excerpt_save_pre', 'wp_filter_post_kses');
add_filter('content_filtered_save_pre', 'wp_filter_post_kses');
}
/**
* Removes all Kses input form content filters.
*
* A quick procedural method to removing all of the filters that kses uses for
* content in WordPress Loop.
*
* Does not remove the kses_init() function from {@see 'init'} hook (priority is
* default). Also does not remove kses_init() function from {@see 'set_current_user'}
* hook (priority is also default).
*
* @since 2.0.6
*/
function kses_remove_filters() {
// Normal filtering
remove_filter('title_save_pre', 'wp_filter_kses');
// Comment filtering
remove_filter( 'pre_comment_content', 'wp_filter_post_kses' );
remove_filter( 'pre_comment_content', 'wp_filter_kses' );
// Post filtering
remove_filter('content_save_pre', 'wp_filter_post_kses');
remove_filter('excerpt_save_pre', 'wp_filter_post_kses');
remove_filter('content_filtered_save_pre', 'wp_filter_post_kses');
}
/**
* Sets up most of the Kses filters for input form content.
*
* If you remove the kses_init() function from {@see 'init'} hook and
* {@see 'set_current_user'} (priority is default), then none of the Kses filter hooks
* will be added.
*
* First removes all of the Kses filters in case the current user does not need
* to have Kses filter the content. If the user does not have unfiltered_html
* capability, then Kses filters are added.
*
* @since 2.0.0
*/
function kses_init() {
kses_remove_filters();
if ( ! current_user_can( 'unfiltered_html' ) ) {
kses_init_filters();
}
}
/**
* Inline CSS filter
*
* @since 2.8.1
*
* @param string $css A string of CSS rules.
* @param string $deprecated Not used.
* @return string Filtered string of CSS rules.
*/
function safecss_filter_attr( $css, $deprecated = '' ) {
if ( ! empty( $deprecated ) ) {
_deprecated_argument( __FUNCTION__, '2.8.1' ); // Never implemented
}
$css = wp_kses_no_null( $css );
$css = str_replace( array( "\n", "\r", "\t" ), '', $css );
$allowed_protocols = wp_allowed_protocols();
$css_array = explode( ';', trim( $css ) );
/**
* Filters list of allowed CSS attributes.
*
* @since 2.8.1
* @since 4.4.0 Added support for `min-height`, `max-height`, `min-width`, and `max-width`.
* @since 4.6.0 Added support for `list-style-type`.
* @since 5.0.0 Added support for `background-image`.
*
* @param array $attr List of allowed CSS attributes.
*/
$allowed_attr = apply_filters( 'safe_style_css', array(
'background',
'background-color',
'background-image',
'border',
'border-width',
'border-color',
'border-style',
'border-right',
'border-right-color',
'border-right-style',
'border-right-width',
'border-bottom',
'border-bottom-color',
'border-bottom-style',
'border-bottom-width',
'border-left',
'border-left-color',
'border-left-style',
'border-left-width',
'border-top',
'border-top-color',
'border-top-style',
'border-top-width',
'border-spacing',
'border-collapse',
'caption-side',
'color',
'font',
'font-family',
'font-size',
'font-style',
'font-variant',
'font-weight',
'letter-spacing',
'line-height',
'text-decoration',
'text-indent',
'text-align',
'height',
'min-height',
'max-height',
'width',
'min-width',
'max-width',
'margin',
'margin-right',
'margin-bottom',
'margin-left',
'margin-top',
'padding',
'padding-right',
'padding-bottom',
'padding-left',
'padding-top',
'clear',
'cursor',
'direction',
'float',
'overflow',
'vertical-align',
'list-style-type',
) );
/*
* CSS attributes that accept URL data types.
*
* This is in accordance to the CSS spec and unrelated to
* the sub-set of supported attributes above.
*
* See: https://developer.mozilla.org/en-US/docs/Web/CSS/url
*/
$css_url_data_types = array(
'background',
'background-image',
'cursor',
'list-style',
'list-style-image',
);
if ( empty( $allowed_attr ) ) {
return $css;
}
$css = '';
foreach ( $css_array as $css_item ) {
if ( $css_item == '' ) {
continue;
}
$css_item = trim( $css_item );
$css_test_string = $css_item;
$found = false;
$url_attr = false;
if ( strpos( $css_item, ':' ) === false ) {
$found = true;
} else {
$parts = explode( ':', $css_item, 2 );
$css_selector = trim( $parts[0] );
if ( in_array( $css_selector, $allowed_attr, true ) ) {
$found = true;
$url_attr = in_array( $css_selector, $css_url_data_types, true );
}
}
if ( $found && $url_attr ) {
// Simplified: matches the sequence `url(*)`.
preg_match_all( '/url\([^)]+\)/', $parts[1], $url_matches );
foreach ( $url_matches[0] as $url_match ) {
// Clean up the URL from each of the matches above.
preg_match( '/^url\(\s*([\'\"]?)(.*)(\g1)\s*\)$/', $url_match, $url_pieces );
if ( empty( $url_pieces[2] ) ) {
$found = false;
break;
}
$url = trim( $url_pieces[2] );
if ( empty( $url ) || $url !== wp_kses_bad_protocol( $url, $allowed_protocols ) ) {
$found = false;
break;
} else {
// Remove the whole `url(*)` bit that was matched above from the CSS.
$css_test_string = str_replace( $url_match, '', $css_test_string );
}
}
}
// Remove any CSS containing containing \ ( & } = or comments, except for url() useage checked above.
if ( $found && ! preg_match( '%[\\\(&=}]|/\*%', $css_test_string ) ) {
if ( $css != '' ) {
$css .= ';';
}
$css .= $css_item;
}
}
return $css;
}
/**
* Helper function to add global attributes to a tag in the allowed html list.
*
* @since 3.5.0
* @since 5.0.0 Add support for `data-*` wildcard attributes.
* @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(
'aria-describedby' => true,
'aria-details' => true,
'aria-label' => true,
'aria-labelledby' => true,
'aria-hidden' => true,
'class' => true,
'id' => true,
'style' => true,
'title' => true,
'role' => true,
'data-*' => true,
);
if ( true === $value )
$value = array();
if ( is_array( $value ) )
return array_merge( $value, $global_attributes );
return $value;
}