3 * XHTML sanitizer for MediaWiki
5 * Copyright (C) 2002-2005 Brion Vibber <brion@pobox.com> et al
6 * http://www.mediawiki.org/
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21 * http://www.gnu.org/copyleft/gpl.html
28 * Regular expression to match various types of character references in
29 * Sanitizer::normalizeCharReferences and Sanitizer::decodeCharReferences
31 define( 'MW_CHAR_REFS_REGEX',
32 '/&([A-Za-z0-9\x80-\xff]+);
39 * Regular expression to match HTML/XML attribute pairs within a tag.
40 * Allows some... latitude.
41 * Used in Sanitizer::fixTagAttributes and Sanitizer::decodeTagAttributes
43 $attrib = '[A-Za-z0-9]';
44 $space = '[\x09\x0a\x0d\x20]';
45 define( 'MW_ATTRIBS_REGEX',
46 "/(?:^|$space)((?:xml:|xmlns:)?$attrib+)
49 # The attribute value: quoted or alone
52 | ([a-zA-Z0-9!#$%&()*,\\-.\\/:;<>?@[\\]^_`{|}~]+)
53 | (\#[0-9a-fA-F]+) # Technically wrong, but lots of
54 # colors are specified like this.
55 # We'll be normalizing it.
57 )?(?=$space|\$)/sx" );
60 * Regular expression to match URIs that could trigger script execution
62 define( 'MW_EVIL_URI_PATTERN', '!(^|\s|\*/\s*)(javascript|vbscript)([^\w]|$)!i' );
65 * Regular expression to match namespace attributes
67 define( 'MW_XMLNS_ATTRIBUTE_PATTRN', "/^xmlns:$attrib+$/" );
70 * List of all named character entities defined in HTML 4.01
71 * http://www.w3.org/TR/html4/sgml/entities.html
74 global $wgHtmlEntities;
75 $wgHtmlEntities = array(
330 * Character entity aliases accepted by MediaWiki
332 global $wgHtmlEntityAliases;
333 $wgHtmlEntityAliases = array(
340 * XHTML sanitizer for MediaWiki
345 * Cleans up HTML, removes dangerous tags and attributes, and
346 * removes HTML comments
348 * @param $text String
349 * @param $processCallback Callback to do any variable or parameter replacements in HTML attribute values
350 * @param $args Array for the processing callback
351 * @param $extratags Array for any extra tags to include
352 * @param $removetags Array for any tags (default or extra) to exclude
355 static function removeHTMLtags( $text, $processCallback = null, $args = array(), $extratags = array(), $removetags = array() ) {
358 static $htmlpairsStatic, $htmlsingle, $htmlsingleonly, $htmlnest, $tabletags,
359 $htmllist, $listtags, $htmlsingleallowed, $htmlelementsStatic, $staticInitialised;
361 wfProfileIn( __METHOD__
);
363 if ( !$staticInitialised ) {
365 $htmlpairsStatic = array( # Tags that must be closed
366 'b', 'del', 'i', 'ins', 'u', 'font', 'big', 'small', 'sub', 'sup', 'h1',
367 'h2', 'h3', 'h4', 'h5', 'h6', 'cite', 'code', 'em', 's',
368 'strike', 'strong', 'tt', 'var', 'div', 'center',
369 'blockquote', 'ol', 'ul', 'dl', 'table', 'caption', 'pre',
370 'ruby', 'rt' , 'rb' , 'rp', 'p', 'span', 'u', 'abbr'
373 'br', 'hr', 'li', 'dt', 'dd'
375 $htmlsingleonly = array( # Elements that cannot have close tags
378 $htmlnest = array( # Tags that can be nested--??
379 'table', 'tr', 'td', 'th', 'div', 'blockquote', 'ol', 'ul',
380 'dl', 'font', 'big', 'small', 'sub', 'sup', 'span'
382 $tabletags = array( # Can only appear inside table, we will close them
385 $htmllist = array( # Tags used by list
388 $listtags = array( # Tags that can appear in a list
392 $htmlsingleallowed = array_unique( array_merge( $htmlsingle, $tabletags ) );
393 $htmlelementsStatic = array_unique( array_merge( $htmlsingle, $htmlpairsStatic, $htmlnest ) );
395 # Convert them all to hashtables for faster lookup
396 $vars = array( 'htmlpairsStatic', 'htmlsingle', 'htmlsingleonly', 'htmlnest', 'tabletags',
397 'htmllist', 'listtags', 'htmlsingleallowed', 'htmlelementsStatic' );
398 foreach ( $vars as $var ) {
399 $
$var = array_flip( $
$var );
401 $staticInitialised = true;
403 # Populate $htmlpairs and $htmlelements with the $extratags and $removetags arrays
404 $extratags = array_flip( $extratags );
405 $removetags = array_flip( $removetags );
406 $htmlpairs = array_merge( $extratags, $htmlpairsStatic );
407 $htmlelements = array_diff_key( array_merge( $extratags, $htmlelementsStatic ) , $removetags );
409 # Remove HTML comments
410 $text = Sanitizer
::removeHTMLcomments( $text );
411 $bits = explode( '<', $text );
412 $text = str_replace( '>', '>', array_shift( $bits ) );
414 $tagstack = $tablestack = array();
415 foreach ( $bits as $x ) {
417 if( preg_match( '!^(/?)(\\w+)([^>]*?)(/{0,1}>)([^<]*)$!', $x, $regs ) ) {
418 list( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
420 $slash = $t = $params = $brace = $rest = null;
424 if ( isset( $htmlelements[$t = strtolower( $t )] ) ) {
428 if( isset( $htmlsingleonly[$t] ) ) {
430 } elseif ( ( $ot = @array_pop
( $tagstack ) ) != $t ) {
431 if ( isset( $htmlsingleallowed[$ot] ) ) {
432 # Pop all elements with an optional close tag
433 # and see if we find a match below them
435 array_push ($optstack, $ot);
436 while ( ( ( $ot = @array_pop
( $tagstack ) ) != $t ) &&
437 isset( $htmlsingleallowed[$ot] ) )
439 array_push ($optstack, $ot);
442 # No match. Push the optinal elements back again
444 while ( $ot = @array_pop
( $optstack ) ) {
445 array_push( $tagstack, $ot );
449 @array_push
( $tagstack, $ot );
450 # <li> can be nested in <ul> or <ol>, skip those cases:
451 if(!(isset( $htmllist[$ot] ) && isset( $listtags[$t] ) )) {
456 if ( $t == 'table' ) {
457 $tagstack = array_pop( $tablestack );
462 # Keep track for later
463 if ( isset( $tabletags[$t] ) &&
464 ! in_array( 'table', $tagstack ) ) {
466 } else if ( in_array( $t, $tagstack ) &&
467 ! isset( $htmlnest [$t ] ) ) {
469 #Â Is it a self closed htmlpair ? (bug 5487)
470 } else if( $brace == '/>' &&
471 isset( $htmlpairs[$t] ) ) {
473 } elseif( isset( $htmlsingleonly[$t] ) ) {
474 # Hack to force empty tag for uncloseable elements
476 } else if( isset( $htmlsingle[$t] ) ) {
477 # Hack to not close $htmlsingle tags
479 } else if( isset( $tabletags[$t] )
480 && in_array($t ,$tagstack) ) {
481 // New table tag but forgot to close the previous one
484 if ( $t == 'table' ) {
485 array_push( $tablestack, $tagstack );
488 array_push( $tagstack, $t );
491 # Replace any variables or template parameters with
493 if( is_callable( $processCallback ) ) {
494 call_user_func_array( $processCallback, array( &$params, $args ) );
497 # Strip non-approved attributes from the tag
498 $newparams = Sanitizer
::fixTagAttributes( $params, $t );
501 $rest = str_replace( '>', '>', $rest );
502 $close = ( $brace == '/>' && !$slash ) ?
' /' : '';
503 $text .= "<$slash$t$newparams$close>$rest";
507 $text .= '<' . str_replace( '>', '>', $x);
509 # Close off any remaining tags
510 while ( is_array( $tagstack ) && ($t = array_pop( $tagstack )) ) {
512 if ( $t == 'table' ) { $tagstack = array_pop( $tablestack ); }
515 # this might be possible using tidy itself
516 foreach ( $bits as $x ) {
517 preg_match( '/^(\\/?)(\\w+)([^>]*?)(\\/{0,1}>)([^<]*)$/',
519 @list
( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
520 if ( isset( $htmlelements[$t = strtolower( $t )] ) ) {
521 if( is_callable( $processCallback ) ) {
522 call_user_func_array( $processCallback, array( &$params, $args ) );
524 $newparams = Sanitizer
::fixTagAttributes( $params, $t );
525 $rest = str_replace( '>', '>', $rest );
526 $text .= "<$slash$t$newparams$brace$rest";
528 $text .= '<' . str_replace( '>', '>', $x);
532 wfProfileOut( __METHOD__
);
537 * Remove '<!--', '-->', and everything between.
538 * To avoid leaving blank lines, when a comment is both preceded
539 * and followed by a newline (ignoring spaces), trim leading and
540 * trailing spaces and one of the newlines.
543 * @param $text String
546 static function removeHTMLcomments( $text ) {
547 wfProfileIn( __METHOD__
);
548 while (($start = strpos($text, '<!--')) !== false) {
549 $end = strpos($text, '-->', $start +
4);
550 if ($end === false) {
551 # Unterminated comment; bail out
557 # Trim space and newline if the comment is both
558 # preceded and followed by a newline
559 $spaceStart = max($start - 1, 0);
560 $spaceLen = $end - $spaceStart;
561 while (substr($text, $spaceStart, 1) === ' ' && $spaceStart > 0) {
565 while (substr($text, $spaceStart +
$spaceLen, 1) === ' ')
567 if (substr($text, $spaceStart, 1) === "\n" and substr($text, $spaceStart +
$spaceLen, 1) === "\n") {
568 # Remove the comment, leading and trailing
569 # spaces, and leave only one newline.
570 $text = substr_replace($text, "\n", $spaceStart, $spaceLen +
1);
573 # Remove just the comment.
574 $text = substr_replace($text, '', $start, $end - $start);
577 wfProfileOut( __METHOD__
);
582 * Take an array of attribute names and values and normalize or discard
583 * illegal values for the given element type.
585 * - Discards attributes not on a whitelist for the given element
586 * - Unsafe style attributes are discarded
587 * - Invalid id attributes are reencoded
589 * @param $attribs Array
590 * @param $element String
593 * @todo Check for legal values where the DTD limits things.
594 * @todo Check for unique id attribute :P
596 static function validateTagAttributes( $attribs, $element ) {
597 return Sanitizer
::validateAttributes( $attribs,
598 Sanitizer
::attributeWhitelist( $element ) );
602 * Take an array of attribute names and values and normalize or discard
603 * illegal values for the given whitelist.
605 * - Discards attributes not the given whitelist
606 * - Unsafe style attributes are discarded
607 * - Invalid id attributes are reencoded
609 * @param $attribs Array
610 * @param $whitelist Array: list of allowed attribute names
613 * @todo Check for legal values where the DTD limits things.
614 * @todo Check for unique id attribute :P
616 static function validateAttributes( $attribs, $whitelist ) {
617 $whitelist = array_flip( $whitelist );
618 $hrefExp = '/^(' . wfUrlProtocols() . ')[^\s]+$/';
621 foreach( $attribs as $attribute => $value ) {
622 #allow XML namespace declaration. Useful especially with RDFa
623 if ( preg_match( MW_XMLNS_ATTRIBUTE_PATTRN
, $attribute ) ) {
624 if ( !preg_match( MW_EVIL_URI_PATTERN
, $value ) ) {
625 $out[$attribute] = $value;
631 if( !isset( $whitelist[$attribute] ) ) {
635 # Strip javascript "expression" from stylesheets.
636 # http://msdn.microsoft.com/workshop/author/dhtml/overview/recalc.asp
637 if( $attribute == 'style' ) {
638 $value = Sanitizer
::checkCss( $value );
639 if( $value === false ) {
645 if ( $attribute === 'id' ) {
646 global $wgEnforceHtmlIds;
647 $value = Sanitizer
::escapeId( $value,
648 $wgEnforceHtmlIds ?
'noninitial' : 'xml' );
651 //RDFa and microdata properties allow URIs. check them
652 if ( $attribute === 'rel' ||
$attribute === 'rev' ||
653 $attribute === 'about' ||
$attribute === 'property' ||
$attribute === 'resource' ||
654 $attribute === 'datatype' ||
$attribute === 'typeof' ||
655 $attribute === 'item' ||
$attribute === 'itemprop' ||
$attribute === 'subject' ) {
657 //Paranoia. Allow "simple" values but suppress javascript
658 if ( preg_match( MW_EVIL_URI_PATTERN
, $value ) ) {
663 # NOTE: even though elements using href/src are not allowed directly, supply
664 # validation code that can be used by tag hook handlers, etc
665 if ( $attribute === 'href' ||
$attribute === 'src' ) {
666 if ( !preg_match( $hrefExp, $value ) ) {
667 continue; //drop any href or src attributes not using an allowed protocol.
668 //NOTE: this also drops all relative URLs
672 // If this attribute was previously set, override it.
673 // Output should only have one attribute of each name.
674 $out[$attribute] = $value;
680 * Merge two sets of HTML attributes. Conflicting items in the second set
681 * will override those in the first, except for 'class' attributes which
682 * will be combined (if they're both strings).
684 * @todo implement merging for other attributes such as style
689 static function mergeAttributes( $a, $b ) {
690 $out = array_merge( $a, $b );
691 if( isset( $a['class'] ) && isset( $b['class'] )
692 && is_string( $a['class'] ) && is_string( $b['class'] )
693 && $a['class'] !== $b['class'] ) {
694 $classes = preg_split( '/\s+/', "{$a['class']} {$b['class']}",
695 -1, PREG_SPLIT_NO_EMPTY
);
696 $out['class'] = implode( ' ', array_unique( $classes ) );
702 * Pick apart some CSS and check it for forbidden or unsafe structures.
703 * Returns a sanitized string, or false if it was just too evil.
705 * Currently URL references, 'expression', 'tps' are forbidden.
707 * @param $value String
710 static function checkCss( $value ) {
711 $stripped = Sanitizer
::decodeCharReferences( $value );
713 // Remove any comments; IE gets token splitting wrong
714 $stripped = StringUtils
::delimiterReplace( '/*', '*/', ' ', $stripped );
718 // ... and continue checks
719 $stripped = preg_replace( '!\\\\([0-9A-Fa-f]{1,6})[ \\n\\r\\t\\f]?!e',
720 'codepointToUtf8(hexdec("$1"))', $stripped );
721 $stripped = str_replace( '\\', '', $stripped );
722 if( preg_match( '/(?:expression|tps*:\/\/|url\\s*\().*/is',
732 * Take a tag soup fragment listing an HTML element's attributes
733 * and normalize it to well-formed XML, discarding unwanted attributes.
734 * Output is safe for further wikitext processing, with escaping of
735 * values that could trigger problems.
737 * - Normalizes attribute names to lowercase
738 * - Discards attributes not on a whitelist for the given element
739 * - Turns broken or invalid entities into plaintext
740 * - Double-quotes all attribute values
741 * - Attributes without values are given the name as attribute
742 * - Double attributes are discarded
743 * - Unsafe style attributes are discarded
744 * - Prepends space if there are attributes.
746 * @param $text String
747 * @param $element String
750 static function fixTagAttributes( $text, $element ) {
751 if( trim( $text ) == '' ) {
755 $stripped = Sanitizer
::validateTagAttributes(
756 Sanitizer
::decodeTagAttributes( $text ), $element );
759 foreach( $stripped as $attribute => $value ) {
760 $encAttribute = htmlspecialchars( $attribute );
761 $encValue = Sanitizer
::safeEncodeAttribute( $value );
763 $attribs[] = "$encAttribute=\"$encValue\"";
765 return count( $attribs ) ?
' ' . implode( ' ', $attribs ) : '';
769 * Encode an attribute value for HTML output.
770 * @param $text String
771 * @return HTML-encoded text fragment
773 static function encodeAttribute( $text ) {
774 $encValue = htmlspecialchars( $text, ENT_QUOTES
);
776 // Whitespace is normalized during attribute decoding,
777 // so if we've been passed non-spaces we must encode them
778 // ahead of time or they won't be preserved.
779 $encValue = strtr( $encValue, array(
789 * Encode an attribute value for HTML tags, with extra armoring
790 * against further wiki processing.
791 * @param $text String
792 * @return HTML-encoded text fragment
794 static function safeEncodeAttribute( $text ) {
795 $encValue = Sanitizer
::encodeAttribute( $text );
797 # Templates and links may be expanded in later parsing,
798 # creating invalid or dangerous output. Suppress this.
799 $encValue = strtr( $encValue, array(
800 '<' => '<', // This should never happen,
801 '>' => '>', // we've received invalid input
802 '"' => '"', // which should have been escaped.
805 "''" => '''',
806 'ISBN' => 'ISBN',
808 'PMID' => 'PMID',
814 $encValue = preg_replace_callback(
815 '/(' . wfUrlProtocols() . ')/',
816 array( 'Sanitizer', 'armorLinksCallback' ),
822 * Given a value escape it so that it can be used in an id attribute and
823 * return it, this does not validate the value however (see first link)
825 * @see http://www.w3.org/TR/html401/types.html#type-name Valid characters
828 * @see http://www.w3.org/TR/html401/struct/links.html#h-12.2.3 Anchors with the id attribute
830 * @param $id String: id to validate
831 * @param $options Mixed: string or array of strings (default is array()):
832 * 'noninitial': This is a non-initial fragment of an id, not a full id,
833 * so don't pay attention if the first character isn't valid at the
834 * beginning of an id.
835 * 'xml': Don't restrict the id to be HTML4-compatible. This option
836 * allows any alphabetic character to be used, per the XML standard.
837 * Therefore, it also completely changes the type of escaping: instead
838 * of weird dot-encoding, runs of invalid characters (mostly
839 * whitespace) are just compressed into a single underscore.
842 static function escapeId( $id, $options = array() ) {
843 $options = (array)$options;
845 if ( !in_array( 'xml', $options ) ) {
846 # HTML4-style escaping
847 static $replace = array(
852 $id = urlencode( Sanitizer
::decodeCharReferences( strtr( $id, ' ', '_' ) ) );
853 $id = str_replace( array_keys( $replace ), array_values( $replace ), $id );
855 if ( !preg_match( '/^[a-zA-Z]/', $id )
856 && !in_array( 'noninitial', $options ) ) {
857 // Initial character must be a letter!
863 # XML-style escaping. For the patterns used, see the XML 1.0 standard,
864 # 5th edition, NameStartChar and NameChar: <http://www.w3.org/TR/REC-xml/>
865 $nameStartChar = ':a-zA-Z_\xC0-\xD6\xD8-\xF6\xF8-\x{2FF}\x{370}-\x{37D}'
866 . '\x{37F}-\x{1FFF}\x{200C}-\x{200D}\x{2070}-\x{218F}\x{2C00}-\x{2FEF}'
867 . '\x{3001}-\x{D7FF}\x{F900}-\x{FDCF}\x{FDF0}-\x{FFFD}\x{10000}-\x{EFFFF}';
868 $nameChar = $nameStartChar . '.\-0-9\xB7\x{0300}-\x{036F}'
869 . '\x{203F}-\x{2040}';
870 # Replace _ as well so we don't get multiple consecutive underscores
871 $id = preg_replace( "/([^$nameChar]|_)+/u", '_', $id );
872 $id = trim( $id, '_' );
874 if ( !preg_match( "/^[$nameStartChar]/u", $id )
875 && !in_array( 'noninitial', $options ) ) {
883 * Given a value, escape it so that it can be used as a CSS class and
886 * @todo For extra validity, input should be validated UTF-8.
888 * @see http://www.w3.org/TR/CSS21/syndata.html Valid characters/format
890 * @param $class String
893 static function escapeClass( $class ) {
894 // Convert ugly stuff to underscores and kill underscores in ugly places
895 return rtrim(preg_replace(
896 array('/(^[0-9\\-])|[\\x00-\\x20!"#$%&\'()*+,.\\/:;<=>?@[\\]^`{|}~]|\\xC2\\xA0/','/_+/'),
902 * Given HTML input, escape with htmlspecialchars but un-escape entites.
903 * This allows (generally harmless) entities like to survive.
905 * @param $html String to escape
906 * @return String: escaped input
908 static function escapeHtmlAllowEntities( $html ) {
909 # It seems wise to escape ' as well as ", as a matter of course. Can't
911 $html = htmlspecialchars( $html, ENT_QUOTES
);
912 $html = str_replace( '&', '&', $html );
913 $html = Sanitizer
::normalizeCharReferences( $html );
918 * Regex replace callback for armoring links against further processing.
919 * @param $matches Array
922 private static function armorLinksCallback( $matches ) {
923 return str_replace( ':', ':', $matches[1] );
927 * Return an associative array of attribute names and values from
928 * a partial tag string. Attribute names are forces to lowercase,
929 * character references are decoded to UTF-8 text.
931 * @param $text String
934 public static function decodeTagAttributes( $text ) {
937 if( trim( $text ) == '' ) {
950 foreach( $pairs as $set ) {
951 $attribute = strtolower( $set[1] );
952 $value = Sanitizer
::getTagAttributeCallback( $set );
954 // Normalize whitespace
955 $value = preg_replace( '/[\t\r\n ]+/', ' ', $value );
956 $value = trim( $value );
958 // Decode character references
959 $attribs[$attribute] = Sanitizer
::decodeCharReferences( $value );
965 * Pick the appropriate attribute value from a match set from the
966 * MW_ATTRIBS_REGEX matches.
971 private static function getTagAttributeCallback( $set ) {
972 if( isset( $set[6] ) ) {
973 # Illegal #XXXXXX color with no quotes.
975 } elseif( isset( $set[5] ) ) {
978 } elseif( isset( $set[4] ) ) {
981 } elseif( isset( $set[3] ) ) {
984 } elseif( !isset( $set[2] ) ) {
985 # In XHTML, attributes must have a value.
986 # For 'reduced' form, return explicitly the attribute name here.
989 throw new MWException( "Tag conditions not met. This should never happen and is a bug." );
994 * Normalize whitespace and character references in an XML source-
995 * encoded text for an attribute value.
997 * See http://www.w3.org/TR/REC-xml/#AVNormalize for background,
998 * but note that we're not returning the value, but are returning
999 * XML source fragments that will be slapped into output.
1001 * @param $text String
1004 private static function normalizeAttributeValue( $text ) {
1005 return str_replace( '"', '"',
1006 self
::normalizeWhitespace(
1007 Sanitizer
::normalizeCharReferences( $text ) ) );
1010 private static function normalizeWhitespace( $text ) {
1011 return preg_replace(
1012 '/\r\n|[\x20\x0d\x0a\x09]/',
1018 * Ensure that any entities and character references are legal
1019 * for XML and XHTML specifically. Any stray bits will be
1020 * &-escaped to result in a valid text fragment.
1022 * a. any named char refs must be known in XHTML
1023 * b. any numeric char refs must be legal chars, not invalid or forbidden
1024 * c. use &#x, not &#X
1025 * d. fix or reject non-valid attributes
1027 * @param $text String
1031 static function normalizeCharReferences( $text ) {
1032 return preg_replace_callback(
1034 array( 'Sanitizer', 'normalizeCharReferencesCallback' ),
1038 * @param $matches String
1041 static function normalizeCharReferencesCallback( $matches ) {
1043 if( $matches[1] != '' ) {
1044 $ret = Sanitizer
::normalizeEntity( $matches[1] );
1045 } elseif( $matches[2] != '' ) {
1046 $ret = Sanitizer
::decCharReference( $matches[2] );
1047 } elseif( $matches[3] != '' ) {
1048 $ret = Sanitizer
::hexCharReference( $matches[3] );
1049 } elseif( $matches[4] != '' ) {
1050 $ret = Sanitizer
::hexCharReference( $matches[4] );
1052 if( is_null( $ret ) ) {
1053 return htmlspecialchars( $matches[0] );
1060 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1061 * return the named entity reference as is. If the entity is a
1062 * MediaWiki-specific alias, returns the HTML equivalent. Otherwise,
1063 * returns HTML-escaped text of pseudo-entity source (eg &foo;)
1065 * @param $name String
1068 static function normalizeEntity( $name ) {
1069 global $wgHtmlEntities, $wgHtmlEntityAliases;
1070 if ( isset( $wgHtmlEntityAliases[$name] ) ) {
1071 return "&{$wgHtmlEntityAliases[$name]};";
1072 } elseif( isset( $wgHtmlEntities[$name] ) ) {
1075 return "&$name;";
1079 static function decCharReference( $codepoint ) {
1080 $point = intval( $codepoint );
1081 if( Sanitizer
::validateCodepoint( $point ) ) {
1082 return sprintf( '&#%d;', $point );
1088 static function hexCharReference( $codepoint ) {
1089 $point = hexdec( $codepoint );
1090 if( Sanitizer
::validateCodepoint( $point ) ) {
1091 return sprintf( '&#x%x;', $point );
1098 * Returns true if a given Unicode codepoint is a valid character in XML.
1099 * @param $codepoint Integer
1102 private static function validateCodepoint( $codepoint ) {
1103 return ($codepoint == 0x09)
1104 ||
($codepoint == 0x0a)
1105 ||
($codepoint == 0x0d)
1106 ||
($codepoint >= 0x20 && $codepoint <= 0xd7ff)
1107 ||
($codepoint >= 0xe000 && $codepoint <= 0xfffd)
1108 ||
($codepoint >= 0x10000 && $codepoint <= 0x10ffff);
1112 * Decode any character references, numeric or named entities,
1113 * in the text and return a UTF-8 string.
1115 * @param $text String
1118 public static function decodeCharReferences( $text ) {
1119 return preg_replace_callback(
1121 array( 'Sanitizer', 'decodeCharReferencesCallback' ),
1126 * @param $matches String
1129 static function decodeCharReferencesCallback( $matches ) {
1130 if( $matches[1] != '' ) {
1131 return Sanitizer
::decodeEntity( $matches[1] );
1132 } elseif( $matches[2] != '' ) {
1133 return Sanitizer
::decodeChar( intval( $matches[2] ) );
1134 } elseif( $matches[3] != '' ) {
1135 return Sanitizer
::decodeChar( hexdec( $matches[3] ) );
1136 } elseif( $matches[4] != '' ) {
1137 return Sanitizer
::decodeChar( hexdec( $matches[4] ) );
1139 # Last case should be an ampersand by itself
1144 * Return UTF-8 string for a codepoint if that is a valid
1145 * character reference, otherwise U+FFFD REPLACEMENT CHARACTER.
1146 * @param $codepoint Integer
1150 static function decodeChar( $codepoint ) {
1151 if( Sanitizer
::validateCodepoint( $codepoint ) ) {
1152 return codepointToUtf8( $codepoint );
1154 return UTF8_REPLACEMENT
;
1159 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1160 * return the UTF-8 encoding of that character. Otherwise, returns
1161 * pseudo-entity source (eg &foo;)
1163 * @param $name Strings
1166 static function decodeEntity( $name ) {
1167 global $wgHtmlEntities, $wgHtmlEntityAliases;
1168 if ( isset( $wgHtmlEntityAliases[$name] ) ) {
1169 $name = $wgHtmlEntityAliases[$name];
1171 if( isset( $wgHtmlEntities[$name] ) ) {
1172 return codepointToUtf8( $wgHtmlEntities[$name] );
1179 * Fetch the whitelist of acceptable attributes for a given element name.
1181 * @param $element String
1184 static function attributeWhitelist( $element ) {
1186 if( !isset( $list ) ) {
1187 $list = Sanitizer
::setupAttributeWhitelist();
1189 return isset( $list[$element] )
1195 * Foreach array key (an allowed HTML element), return an array
1196 * of allowed attributes
1199 static function setupAttributeWhitelist() {
1200 global $wgAllowRdfaAttributes, $wgHtml5, $wgAllowItemAttributes;
1202 $common = array( 'id', 'class', 'lang', 'dir', 'title', 'style', 'xml:lang' );
1204 if ( $wgAllowRdfaAttributes ) {
1205 #RDFa attributes as specified in section 9 of http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014
1206 $common = array_merge( $common, array(
1207 'about', 'property', 'resource', 'datatype', 'typeof',
1211 if ( $wgHtml5 && $wgAllowItemAttributes ) {
1212 # add HTML5 microdata tages as pecified by http://www.w3.org/TR/html5/microdata.html
1213 $common = array_merge( $common, array(
1214 'item', 'itemprop', 'subject'
1218 $block = array_merge( $common, array( 'align' ) );
1219 $tablealign = array( 'align', 'char', 'charoff', 'valign' );
1220 $tablecell = array( 'abbr',
1226 'nowrap', # deprecated
1227 'width', # deprecated
1228 'height', # deprecated
1229 'bgcolor' # deprecated
1232 # Numbers refer to sections in HTML 4.01 standard describing the element.
1233 # See: http://www.w3.org/TR/html4/
1234 $whitelist = array (
1237 'center' => $common, # deprecated
1238 'span' => $block, # ??
1256 'strong' => $common,
1267 'blockquote' => array_merge( $common, array( 'cite' ) ),
1278 'br' => array( 'id', 'class', 'title', 'style', 'clear' ),
1281 'pre' => array_merge( $common, array( 'width' ) ),
1284 'ins' => array_merge( $common, array( 'cite', 'datetime' ) ),
1285 'del' => array_merge( $common, array( 'cite', 'datetime' ) ),
1288 'ul' => array_merge( $common, array( 'type' ) ),
1289 'ol' => array_merge( $common, array( 'type', 'start' ) ),
1290 'li' => array_merge( $common, array( 'type', 'value' ) ),
1298 'table' => array_merge( $common,
1299 array( 'summary', 'width', 'border', 'frame',
1300 'rules', 'cellspacing', 'cellpadding',
1305 'caption' => array_merge( $common, array( 'align' ) ),
1308 'thead' => array_merge( $common, $tablealign ),
1309 'tfoot' => array_merge( $common, $tablealign ),
1310 'tbody' => array_merge( $common, $tablealign ),
1313 'colgroup' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
1314 'col' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
1317 'tr' => array_merge( $common, array( 'bgcolor' ), $tablealign ),
1320 'td' => array_merge( $common, $tablecell, $tablealign ),
1321 'th' => array_merge( $common, $tablecell, $tablealign ),
1323 # 12.2 # NOTE: <a> is not allowed directly, but the attrib whitelist is used from the Parser object
1324 'a' => array_merge( $common, array( 'href', 'rel', 'rev' ) ), # rel/rev esp. for RDFa
1327 # Not usually allowed, but may be used for extension-style hooks
1328 # such as <math> when it is rasterized
1329 'img' => array_merge( $common, array( 'alt' ) ),
1337 'strike' => $common,
1342 'font' => array_merge( $common, array( 'size', 'color', 'face' ) ),
1346 'hr' => array_merge( $common, array( 'noshade', 'size', 'width' ) ),
1348 # XHTML Ruby annotation text module, simple ruby only.
1349 # http://www.w3c.org/TR/ruby/
1354 'rt' => $common, #array_merge( $common, array( 'rbspan' ) ),
1357 # MathML root element, where used for extensions
1358 # 'title' may not be 100% valid here; it's XHTML
1359 # http://www.w3.org/TR/REC-MathML/
1360 'math' => array( 'class', 'style', 'id', 'title' ),
1366 * Take a fragment of (potentially invalid) HTML and return
1367 * a version with any tags removed, encoded as plain text.
1369 * Warning: this return value must be further escaped for literal
1370 * inclusion in HTML output as of 1.10!
1372 * @param $text String: HTML fragment
1375 static function stripAllTags( $text ) {
1377 $text = StringUtils
::delimiterReplace( '<', '>', '', $text );
1379 # Normalize &entities and whitespace
1380 $text = self
::decodeCharReferences( $text );
1381 $text = self
::normalizeWhitespace( $text );
1387 * Hack up a private DOCTYPE with HTML's standard entity declarations.
1388 * PHP 4 seemed to know these if you gave it an HTML doctype, but
1391 * Use for passing XHTML fragments to PHP's XML parsing functions
1395 static function hackDocType() {
1396 global $wgHtmlEntities;
1397 $out = "<!DOCTYPE html [\n";
1398 foreach( $wgHtmlEntities as $entity => $codepoint ) {
1399 $out .= "<!ENTITY $entity \"&#$codepoint;\">";
1405 static function cleanUrl( $url ) {
1406 # Normalize any HTML entities in input. They will be
1407 # re-escaped by makeExternalLink().
1408 $url = Sanitizer
::decodeCharReferences( $url );
1410 # Escape any control characters introduced by the above step
1411 $url = preg_replace( '/[\][<>"\\x00-\\x20\\x7F]/e', "urlencode('\\0')", $url );
1413 # Validate hostname portion
1415 if( preg_match( '!^([^:]+:)(//[^/]+)?(.*)$!iD', $url, $matches ) ) {
1416 list( /* $whole */, $protocol, $host, $rest ) = $matches;
1418 // Characters that will be ignored in IDNs.
1419 // http://tools.ietf.org/html/3454#section-3.1
1420 // Strip them before further processing so blacklists and such work.
1422 \\s| # general whitespace
1423 \xc2\xad| # 00ad SOFT HYPHEN
1424 \xe1\xa0\x86| # 1806 MONGOLIAN TODO SOFT HYPHEN
1425 \xe2\x80\x8b| # 200b ZERO WIDTH SPACE
1426 \xe2\x81\xa0| # 2060 WORD JOINER
1427 \xef\xbb\xbf| # feff ZERO WIDTH NO-BREAK SPACE
1428 \xcd\x8f| # 034f COMBINING GRAPHEME JOINER
1429 \xe1\xa0\x8b| # 180b MONGOLIAN FREE VARIATION SELECTOR ONE
1430 \xe1\xa0\x8c| # 180c MONGOLIAN FREE VARIATION SELECTOR TWO
1431 \xe1\xa0\x8d| # 180d MONGOLIAN FREE VARIATION SELECTOR THREE
1432 \xe2\x80\x8c| # 200c ZERO WIDTH NON-JOINER
1433 \xe2\x80\x8d| # 200d ZERO WIDTH JOINER
1434 [\xef\xb8\x80-\xef\xb8\x8f] # fe00-fe00f VARIATION SELECTOR-1-16
1437 $host = preg_replace( $strip, '', $host );
1439 // @fixme: validate hostnames here
1441 return $protocol . $host . $rest;