3 * XHTML sanitizer for MediaWiki
5 * Copyright © 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 * XHTML sanitizer for MediaWiki
33 * Regular expression to match various types of character references in
34 * Sanitizer::normalizeCharReferences and Sanitizer::decodeCharReferences
36 const CHAR_REFS_REGEX
=
37 '/&([A-Za-z0-9\x80-\xff]+);
39 |&\#[xX]([0-9A-Fa-f]+);
43 * Blacklist for evil uris like javascript:
44 * WARNING: DO NOT use this in any place that actually requires blacklisting
45 * for security reasons. There are NUMEROUS[1] ways to bypass blacklisting, the
46 * only way to be secure from javascript: uri based xss vectors is to whitelist
47 * things that you know are safe and deny everything else.
48 * [1]: http://ha.ckers.org/xss.html
50 const EVIL_URI_PATTERN
= '!(^|\s|\*/\s*)(javascript|vbscript)([^\w]|$)!i';
51 const XMLNS_ATTRIBUTE_PATTERN
= "/^xmlns:[:A-Z_a-z-.0-9]+$/";
54 * List of all named character entities defined in HTML 4.01
55 * http://www.w3.org/TR/html4/sgml/entities.html
56 * As well as ' which is only defined starting in XHTML1.
59 static $htmlEntities = array(
75 'apos' => 39, // New in XHTML & HTML 5; avoid in output for compatibility with IE.
316 * Character entity aliases accepted by MediaWiki
318 static $htmlEntityAliases = array(
324 * Lazy-initialised attributes regex, see getAttribsRegex()
326 static $attribsRegex;
329 * Regular expression to match HTML/XML attribute pairs within a tag.
330 * Allows some... latitude.
331 * Used in Sanitizer::fixTagAttributes and Sanitizer::decodeTagAttributes
333 static function getAttribsRegex() {
334 if ( self
::$attribsRegex === null ) {
335 $attribFirst = '[:A-Z_a-z0-9]';
336 $attrib = '[:A-Z_a-z-.0-9]';
337 $space = '[\x09\x0a\x0d\x20]';
338 self
::$attribsRegex =
339 "/(?:^|$space)({$attribFirst}{$attrib}*)
342 # The attribute value: quoted or alone
345 | ([a-zA-Z0-9!#$%&()*,\\-.\\/:;<>?@[\\]^_`{|}~]+)
346 | (\#[0-9a-fA-F]+) # Technically wrong, but lots of
347 # colors are specified like this.
348 # We'll be normalizing it.
352 return self
::$attribsRegex;
356 * Cleans up HTML, removes dangerous tags and attributes, and
357 * removes HTML comments
359 * @param $text String
360 * @param $processCallback Callback to do any variable or parameter replacements in HTML attribute values
361 * @param $args Array for the processing callback
362 * @param $extratags Array for any extra tags to include
363 * @param $removetags Array for any tags (default or extra) to exclude
366 static function removeHTMLtags( $text, $processCallback = null, $args = array(), $extratags = array(), $removetags = array() ) {
369 static $htmlpairsStatic, $htmlsingle, $htmlsingleonly, $htmlnest, $tabletags,
370 $htmllist, $listtags, $htmlsingleallowed, $htmlelementsStatic, $staticInitialised;
372 wfProfileIn( __METHOD__
);
374 if ( !$staticInitialised ) {
376 $htmlpairsStatic = array( # Tags that must be closed
377 'b', 'del', 'i', 'ins', 'u', 'font', 'big', 'small', 'sub', 'sup', 'h1',
378 'h2', 'h3', 'h4', 'h5', 'h6', 'cite', 'code', 'em', 's',
379 'strike', 'strong', 'tt', 'var', 'div', 'center',
380 'blockquote', 'ol', 'ul', 'dl', 'table', 'caption', 'pre',
381 'ruby', 'rt' , 'rb' , 'rp', 'p', 'span', 'abbr', 'dfn',
385 'br', 'hr', 'li', 'dt', 'dd'
387 $htmlsingleonly = array( # Elements that cannot have close tags
390 $htmlnest = array( # Tags that can be nested--??
391 'table', 'tr', 'td', 'th', 'div', 'blockquote', 'ol', 'ul',
392 'dl', 'font', 'big', 'small', 'sub', 'sup', 'span'
394 $tabletags = array( # Can only appear inside table, we will close them
397 $htmllist = array( # Tags used by list
400 $listtags = array( # Tags that can appear in a list
404 global $wgAllowImageTag;
405 if ( $wgAllowImageTag ) {
406 $htmlsingle[] = 'img';
407 $htmlsingleonly[] = 'img';
411 if ( $wgAllowATag ) {
412 $htmlpairsStatic[] = 'a';
415 $htmlsingleallowed = array_unique( array_merge( $htmlsingle, $tabletags ) );
416 $htmlelementsStatic = array_unique( array_merge( $htmlsingle, $htmlpairsStatic, $htmlnest ) );
418 # Convert them all to hashtables for faster lookup
419 $vars = array( 'htmlpairsStatic', 'htmlsingle', 'htmlsingleonly', 'htmlnest', 'tabletags',
420 'htmllist', 'listtags', 'htmlsingleallowed', 'htmlelementsStatic' );
421 foreach ( $vars as $var ) {
422 $
$var = array_flip( $
$var );
424 $staticInitialised = true;
426 # Populate $htmlpairs and $htmlelements with the $extratags and $removetags arrays
427 $extratags = array_flip( $extratags );
428 $removetags = array_flip( $removetags );
429 $htmlpairs = array_merge( $extratags, $htmlpairsStatic );
430 $htmlelements = array_diff_key( array_merge( $extratags, $htmlelementsStatic ) , $removetags );
432 # Remove HTML comments
433 $text = Sanitizer
::removeHTMLcomments( $text );
434 $bits = explode( '<', $text );
435 $text = str_replace( '>', '>', array_shift( $bits ) );
437 $tagstack = $tablestack = array();
438 foreach ( $bits as $x ) {
440 # $slash: Does the current element start with a '/'?
441 # $t: Current element name
442 # $params: String between element name and >
443 # $brace: Ending '>' or '/>'
444 # $rest: Everything until the next element of $bits
445 if( preg_match( '!^(/?)(\\w+)([^>]*?)(/{0,1}>)([^<]*)$!', $x, $regs ) ) {
446 list( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
448 $slash = $t = $params = $brace = $rest = null;
452 if ( isset( $htmlelements[$t = strtolower( $t )] ) ) {
454 if ( $slash && isset( $htmlsingleonly[$t] ) ) {
456 } elseif ( $slash ) {
457 # Closing a tag... is it the one we just opened?
458 $ot = @array_pop
( $tagstack );
460 if ( isset( $htmlsingleallowed[$ot] ) ) {
461 # Pop all elements with an optional close tag
462 # and see if we find a match below them
464 array_push( $optstack, $ot );
465 wfSuppressWarnings();
466 $ot = array_pop( $tagstack );
468 while ( $ot != $t && isset( $htmlsingleallowed[$ot] ) ) {
469 array_push( $optstack, $ot );
470 wfSuppressWarnings();
471 $ot = array_pop( $tagstack );
475 # No match. Push the optional elements back again
477 wfSuppressWarnings();
478 $ot = array_pop( $optstack );
481 array_push( $tagstack, $ot );
482 wfSuppressWarnings();
483 $ot = array_pop( $optstack );
488 @array_push
( $tagstack, $ot );
489 # <li> can be nested in <ul> or <ol>, skip those cases:
490 if ( !isset( $htmllist[$ot] ) ||
!isset( $listtags[$t] ) ) {
495 if ( $t == 'table' ) {
496 $tagstack = array_pop( $tablestack );
501 # Keep track for later
502 if ( isset( $tabletags[$t] ) &&
503 !in_array( 'table', $tagstack ) ) {
505 } elseif ( in_array( $t, $tagstack ) &&
506 !isset( $htmlnest [$t ] ) ) {
508 # Is it a self closed htmlpair ? (bug 5487)
509 } elseif ( $brace == '/>' &&
510 isset( $htmlpairs[$t] ) ) {
512 } elseif ( isset( $htmlsingleonly[$t] ) ) {
513 # Hack to force empty tag for uncloseable elements
515 } elseif ( isset( $htmlsingle[$t] ) ) {
516 # Hack to not close $htmlsingle tags
518 } elseif ( isset( $tabletags[$t] )
519 && in_array( $t, $tagstack ) ) {
520 // New table tag but forgot to close the previous one
523 if ( $t == 'table' ) {
524 array_push( $tablestack, $tagstack );
527 array_push( $tagstack, $t );
530 # Replace any variables or template parameters with
532 if( is_callable( $processCallback ) ) {
533 call_user_func_array( $processCallback, array( &$params, $args ) );
536 # Strip non-approved attributes from the tag
537 $newparams = Sanitizer
::fixTagAttributes( $params, $t );
540 $rest = str_replace( '>', '>', $rest );
541 $close = ( $brace == '/>' && !$slash ) ?
' /' : '';
542 $text .= "<$slash$t$newparams$close>$rest";
546 $text .= '<' . str_replace( '>', '>', $x);
548 # Close off any remaining tags
549 while ( is_array( $tagstack ) && ($t = array_pop( $tagstack )) ) {
551 if ( $t == 'table' ) { $tagstack = array_pop( $tablestack ); }
554 # this might be possible using tidy itself
555 foreach ( $bits as $x ) {
556 preg_match( '/^(\\/?)(\\w+)([^>]*?)(\\/{0,1}>)([^<]*)$/',
558 @list
( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
559 if ( isset( $htmlelements[$t = strtolower( $t )] ) ) {
560 if( is_callable( $processCallback ) ) {
561 call_user_func_array( $processCallback, array( &$params, $args ) );
563 $newparams = Sanitizer
::fixTagAttributes( $params, $t );
564 $rest = str_replace( '>', '>', $rest );
565 $text .= "<$slash$t$newparams$brace$rest";
567 $text .= '<' . str_replace( '>', '>', $x);
571 wfProfileOut( __METHOD__
);
576 * Remove '<!--', '-->', and everything between.
577 * To avoid leaving blank lines, when a comment is both preceded
578 * and followed by a newline (ignoring spaces), trim leading and
579 * trailing spaces and one of the newlines.
582 * @param $text String
585 static function removeHTMLcomments( $text ) {
586 wfProfileIn( __METHOD__
);
587 while (($start = strpos($text, '<!--')) !== false) {
588 $end = strpos($text, '-->', $start +
4);
589 if ($end === false) {
590 # Unterminated comment; bail out
596 # Trim space and newline if the comment is both
597 # preceded and followed by a newline
598 $spaceStart = max($start - 1, 0);
599 $spaceLen = $end - $spaceStart;
600 while (substr($text, $spaceStart, 1) === ' ' && $spaceStart > 0) {
604 while (substr($text, $spaceStart +
$spaceLen, 1) === ' ')
606 if (substr($text, $spaceStart, 1) === "\n" and substr($text, $spaceStart +
$spaceLen, 1) === "\n") {
607 # Remove the comment, leading and trailing
608 # spaces, and leave only one newline.
609 $text = substr_replace($text, "\n", $spaceStart, $spaceLen +
1);
612 # Remove just the comment.
613 $text = substr_replace($text, '', $start, $end - $start);
616 wfProfileOut( __METHOD__
);
621 * Take an array of attribute names and values and fix some deprecated values
622 * for the given element type.
623 * This does not validate properties, so you should ensure that you call
624 * validateTagAttributes AFTER this to ensure that the resulting style rule
625 * this may add is safe.
627 * - Converts most presentational attributes like align into inline css
629 * @param $attribs Array
630 * @param $element String
633 static function fixDeprecatedAttributes( $attribs, $element ) {
634 global $wgHtml5, $wgCleanupPresentationalAttributes;
636 // presentational attributes were removed from html5, we can leave them
637 // in when html5 is turned off
638 if ( !$wgHtml5 ||
!$wgCleanupPresentationalAttributes ) {
642 $table = array( 'table' );
643 $cells = array( 'td', 'th' );
644 $colls = array( 'col', 'colgroup' );
645 $tblocks = array( 'tbody', 'tfoot', 'thead' );
646 $h = array( 'h1', 'h2', 'h3', 'h4', 'h5', 'h6' );
648 $presentationalAttribs = array(
649 'align' => array( 'text-align', array_merge( array( 'caption', 'hr', 'div', 'p', 'tr' ), $table, $cells, $colls, $tblocks, $h ) ),
650 'clear' => array( 'clear', array( 'br' ) ),
651 'height' => array( 'height', $cells ),
652 'nowrap' => array( 'white-space', $cells ),
653 'size' => array( 'height', array( 'hr' ) ),
654 'type' => array( 'list-style-type', array( 'li', 'ol', 'ul' ) ),
655 'valign' => array( 'vertical-align', array_merge( $cells, $colls, $tblocks ) ),
656 'width' => array( 'width', array_merge( array( 'hr', 'pre' ), $table, $cells, $colls ) ),
659 // Ensure that any upper case or mixed case attributes are converted to lowercase
660 foreach ( $attribs as $attribute => $value ) {
661 if ( $attribute !== strtolower( $attribute ) && array_key_exists( strtolower( $attribute ), $presentationalAttribs ) ) {
662 $attribs[strtolower( $attribute )] = $value;
663 unset( $attribs[$attribute] );
668 foreach ( $presentationalAttribs as $attribute => $info ) {
669 list( $property, $elements ) = $info;
671 // Skip if this attribute is not relevant to this element
672 if ( !in_array( $element, $elements ) ) {
676 // Skip if the attribute is not used
677 if ( !array_key_exists( $attribute, $attribs ) ) {
681 $value = $attribs[$attribute];
683 // For nowrap the value should be nowrap instead of whatever text is in the value
684 if ( $attribute === 'nowrap' ) {
688 // clear="all" is clear: both; in css
689 if ( $attribute === 'clear' && strtolower( $value ) === 'all' ) {
693 // Size based properties should have px applied to them if they have no unit
694 if ( in_array( $attribute, array( 'height', 'width', 'size' ) ) ) {
695 if ( preg_match( '/^[\d.]+$/', $value ) ) {
696 $value = "{$value}px";
700 $style .= " $property: $value;";
702 unset( $attribs[$attribute] );
706 // Prepend our style rules so that they can be overridden by user css
707 if ( isset($attribs['style']) ) {
708 $style .= " " . $attribs['style'];
710 $attribs['style'] = trim($style);
717 * Take an array of attribute names and values and normalize or discard
718 * illegal values for the given element type.
720 * - Discards attributes not on a whitelist for the given element
721 * - Unsafe style attributes are discarded
722 * - Invalid id attributes are reencoded
724 * @param $attribs Array
725 * @param $element String
728 * @todo Check for legal values where the DTD limits things.
729 * @todo Check for unique id attribute :P
731 static function validateTagAttributes( $attribs, $element ) {
732 return Sanitizer
::validateAttributes( $attribs,
733 Sanitizer
::attributeWhitelist( $element ) );
737 * Take an array of attribute names and values and normalize or discard
738 * illegal values for the given whitelist.
740 * - Discards attributes not the given whitelist
741 * - Unsafe style attributes are discarded
742 * - Invalid id attributes are reencoded
744 * @param $attribs Array
745 * @param $whitelist Array: list of allowed attribute names
748 * @todo Check for legal values where the DTD limits things.
749 * @todo Check for unique id attribute :P
751 static function validateAttributes( $attribs, $whitelist ) {
752 global $wgAllowRdfaAttributes, $wgAllowMicrodataAttributes, $wgHtml5;
754 $whitelist = array_flip( $whitelist );
755 $hrefExp = '/^(' . wfUrlProtocols() . ')[^\s]+$/';
758 foreach( $attribs as $attribute => $value ) {
759 #allow XML namespace declaration if RDFa is enabled
760 if ( $wgAllowRdfaAttributes && preg_match( self
::XMLNS_ATTRIBUTE_PATTERN
, $attribute ) ) {
761 if ( !preg_match( self
::EVIL_URI_PATTERN
, $value ) ) {
762 $out[$attribute] = $value;
768 # Allow any attribute beginning with "data-", if in HTML5 mode
769 if ( !($wgHtml5 && preg_match( '/^data-/i', $attribute )) && !isset( $whitelist[$attribute] ) ) {
773 # Strip javascript "expression" from stylesheets.
774 # http://msdn.microsoft.com/workshop/author/dhtml/overview/recalc.asp
775 if( $attribute == 'style' ) {
776 $value = Sanitizer
::checkCss( $value );
779 if ( $attribute === 'id' ) {
780 $value = Sanitizer
::escapeId( $value, 'noninitial' );
783 //RDFa and microdata properties allow URLs, URIs and/or CURIs. check them for sanity
784 if ( $attribute === 'rel' ||
$attribute === 'rev' ||
785 $attribute === 'about' ||
$attribute === 'property' ||
$attribute === 'resource' ||
#RDFa
786 $attribute === 'datatype' ||
$attribute === 'typeof' ||
#RDFa
787 $attribute === 'itemid' ||
$attribute === 'itemprop' ||
$attribute === 'itemref' ||
#HTML5 microdata
788 $attribute === 'itemscope' ||
$attribute === 'itemtype' ) { #HTML5 microdata
790 //Paranoia. Allow "simple" values but suppress javascript
791 if ( preg_match( self
::EVIL_URI_PATTERN
, $value ) ) {
796 # NOTE: even though elements using href/src are not allowed directly, supply
797 # validation code that can be used by tag hook handlers, etc
798 if ( $attribute === 'href' ||
$attribute === 'src' ) {
799 if ( !preg_match( $hrefExp, $value ) ) {
800 continue; //drop any href or src attributes not using an allowed protocol.
801 //NOTE: this also drops all relative URLs
805 if ( $attribute === 'href' ||
$attribute === 'src' ) {
806 if ( !preg_match( $hrefExp, $value ) ) {
807 continue; //drop any href or src attributes not using an allowed protocol.
808 //NOTE: this also drops all relative URLs
812 //RDFa properties allow URIs. check them
813 if ( $attribute === 'rel' ||
$attribute === 'rev' ||
814 $attribute === 'about' ||
$attribute === 'property' ||
$attribute === 'resource' ||
815 $attribute === 'datatype' ||
$attribute === 'typeof' ) {
816 //Paranoia. Allow "simple" values but suppress javascript
817 if ( preg_match( '/(^|\s)javascript\s*:/i', $value ) ) {
822 // If this attribute was previously set, override it.
823 // Output should only have one attribute of each name.
824 $out[$attribute] = $value;
827 if ( $wgAllowMicrodataAttributes ) {
828 # itemtype, itemid, itemref don't make sense without itemscope
829 if ( !array_key_exists( 'itemscope', $out ) ) {
830 unset( $out['itemtype'] );
831 unset( $out['itemid'] );
832 unset( $out['itemref'] );
834 # TODO: Strip itemprop if we aren't descendants of an itemscope.
840 * Merge two sets of HTML attributes. Conflicting items in the second set
841 * will override those in the first, except for 'class' attributes which
842 * will be combined (if they're both strings).
844 * @todo implement merging for other attributes such as style
849 static function mergeAttributes( $a, $b ) {
850 $out = array_merge( $a, $b );
851 if( isset( $a['class'] ) && isset( $b['class'] )
852 && is_string( $a['class'] ) && is_string( $b['class'] )
853 && $a['class'] !== $b['class'] ) {
854 $classes = preg_split( '/\s+/', "{$a['class']} {$b['class']}",
855 -1, PREG_SPLIT_NO_EMPTY
);
856 $out['class'] = implode( ' ', array_unique( $classes ) );
862 * Pick apart some CSS and check it for forbidden or unsafe structures.
863 * Returns a sanitized string. This sanitized string will have
864 * character references and escape sequences decoded, and comments
865 * stripped. If the input is just too evil, only a comment complaining
866 * about evilness will be returned.
868 * Currently URL references, 'expression', 'tps' are forbidden.
870 * NOTE: Despite the fact that character references are decoded, the
871 * returned string may contain character references given certain
872 * clever input strings. These character references must
873 * be escaped before the return value is embedded in HTML.
875 * @param $value String
878 static function checkCss( $value ) {
879 // Decode character references like {
880 $value = Sanitizer
::decodeCharReferences( $value );
882 // Decode escape sequences and line continuation
883 // See the grammar in the CSS 2 spec, appendix D.
884 // This has to be done AFTER decoding character references.
885 // This means it isn't possible for this function to return
886 // unsanitized escape sequences. It is possible to manufacture
887 // input that contains character references that decode to
888 // escape sequences that decode to character references, but
889 // it's OK for the return value to contain character references
890 // because the caller is supposed to escape those anyway.
892 if ( !$decodeRegex ) {
893 $space = '[\\x20\\t\\r\\n\\f]';
894 $nl = '(?:\\n|\\r\\n|\\r|\\f)';
896 $decodeRegex = "/ $backslash
898 ($nl) | # 1. Line continuation
899 ([0-9A-Fa-f]{1,6})$space? | # 2. character number
900 (.) | # 3. backslash cancelling special meaning
901 () | # 4. backslash at end of string
904 $value = preg_replace_callback( $decodeRegex,
905 array( __CLASS__
, 'cssDecodeCallback' ), $value );
907 // Remove any comments; IE gets token splitting wrong
908 // This must be done AFTER decoding character references and
909 // escape sequences, because those steps can introduce comments
910 // This step cannot introduce character references or escape
911 // sequences, because it replaces comments with spaces rather
912 // than removing them completely.
913 $value = StringUtils
::delimiterReplace( '/*', '*/', ' ', $value );
915 // Remove anything after a comment-start token, to guard against
916 // incorrect client implementations.
917 $commentPos = strpos( $value, '/*' );
918 if ( $commentPos !== false ) {
919 $value = substr( $value, 0, $commentPos );
922 // Reject problematic keywords and control characters
923 if ( preg_match( '/[\000-\010\016-\037\177]/', $value ) ) {
924 return '/* invalid control char */';
925 } elseif ( preg_match( '! expression | filter\s*: | accelerator\s*: | url\s*\( !ix', $value ) ) {
926 return '/* insecure input */';
932 * @param $matches array
935 static function cssDecodeCallback( $matches ) {
936 if ( $matches[1] !== '' ) {
939 } elseif ( $matches[2] !== '' ) {
940 $char = codepointToUtf8( hexdec( $matches[2] ) );
941 } elseif ( $matches[3] !== '' ) {
946 if ( $char == "\n" ||
$char == '"' ||
$char == "'" ||
$char == '\\' ) {
947 // These characters need to be escaped in strings
948 // Clean up the escape sequence to avoid parsing errors by clients
949 return '\\' . dechex( ord( $char ) ) . ' ';
951 // Decode unnecessary escape
957 * Take a tag soup fragment listing an HTML element's attributes
958 * and normalize it to well-formed XML, discarding unwanted attributes.
959 * Output is safe for further wikitext processing, with escaping of
960 * values that could trigger problems.
962 * - Normalizes attribute names to lowercase
963 * - Discards attributes not on a whitelist for the given element
964 * - Turns broken or invalid entities into plaintext
965 * - Double-quotes all attribute values
966 * - Attributes without values are given the name as attribute
967 * - Double attributes are discarded
968 * - Unsafe style attributes are discarded
969 * - Prepends space if there are attributes.
971 * @param $text String
972 * @param $element String
975 static function fixTagAttributes( $text, $element ) {
976 if( trim( $text ) == '' ) {
980 $decoded = Sanitizer
::decodeTagAttributes( $text );
981 $decoded = Sanitizer
::fixDeprecatedAttributes( $decoded, $element );
982 $stripped = Sanitizer
::validateTagAttributes( $decoded, $element );
985 foreach( $stripped as $attribute => $value ) {
986 $encAttribute = htmlspecialchars( $attribute );
987 $encValue = Sanitizer
::safeEncodeAttribute( $value );
989 $attribs[] = "$encAttribute=\"$encValue\"";
991 return count( $attribs ) ?
' ' . implode( ' ', $attribs ) : '';
995 * Encode an attribute value for HTML output.
996 * @param $text String
997 * @return HTML-encoded text fragment
999 static function encodeAttribute( $text ) {
1000 $encValue = htmlspecialchars( $text, ENT_QUOTES
);
1002 // Whitespace is normalized during attribute decoding,
1003 // so if we've been passed non-spaces we must encode them
1004 // ahead of time or they won't be preserved.
1005 $encValue = strtr( $encValue, array(
1015 * Encode an attribute value for HTML tags, with extra armoring
1016 * against further wiki processing.
1017 * @param $text String
1018 * @return HTML-encoded text fragment
1020 static function safeEncodeAttribute( $text ) {
1021 $encValue = Sanitizer
::encodeAttribute( $text );
1023 # Templates and links may be expanded in later parsing,
1024 # creating invalid or dangerous output. Suppress this.
1025 $encValue = strtr( $encValue, array(
1026 '<' => '<', // This should never happen,
1027 '>' => '>', // we've received invalid input
1028 '"' => '"', // which should have been escaped.
1031 "''" => '''',
1032 'ISBN' => 'ISBN',
1034 'PMID' => 'PMID',
1040 $encValue = preg_replace_callback(
1041 '/(' . wfUrlProtocols() . ')/',
1042 array( 'Sanitizer', 'armorLinksCallback' ),
1048 * Given a value, escape it so that it can be used in an id attribute and
1049 * return it. This will use HTML5 validation if $wgExperimentalHtmlIds is
1050 * true, allowing anything but ASCII whitespace. Otherwise it will use
1051 * HTML 4 rules, which means a narrow subset of ASCII, with bad characters
1052 * escaped with lots of dots.
1054 * To ensure we don't have to bother escaping anything, we also strip ', ",
1055 * & even if $wgExperimentalIds is true. TODO: Is this the best tactic?
1056 * We also strip # because it upsets IE, and % because it could be
1057 * ambiguous if it's part of something that looks like a percent escape
1058 * (which don't work reliably in fragments cross-browser).
1060 * @see http://www.w3.org/TR/html401/types.html#type-name Valid characters
1063 * @see http://www.w3.org/TR/html401/struct/links.html#h-12.2.3 Anchors with the id attribute
1064 * @see http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#the-id-attribute
1065 * HTML5 definition of id attribute
1067 * @param $id String: id to escape
1068 * @param $options Mixed: string or array of strings (default is array()):
1069 * 'noninitial': This is a non-initial fragment of an id, not a full id,
1070 * so don't pay attention if the first character isn't valid at the
1071 * beginning of an id. Only matters if $wgExperimentalHtmlIds is
1073 * 'legacy': Behave the way the old HTML 4-based ID escaping worked even
1074 * if $wgExperimentalHtmlIds is used, so we can generate extra
1075 * anchors and links won't break.
1078 static function escapeId( $id, $options = array() ) {
1079 global $wgHtml5, $wgExperimentalHtmlIds;
1080 $options = (array)$options;
1082 if ( $wgHtml5 && $wgExperimentalHtmlIds && !in_array( 'legacy', $options ) ) {
1083 $id = Sanitizer
::decodeCharReferences( $id );
1084 $id = preg_replace( '/[ \t\n\r\f_\'"&#%]+/', '_', $id );
1085 $id = trim( $id, '_' );
1087 # Must have been all whitespace to start with.
1094 # HTML4-style escaping
1095 static $replace = array(
1100 $id = urlencode( Sanitizer
::decodeCharReferences( strtr( $id, ' ', '_' ) ) );
1101 $id = str_replace( array_keys( $replace ), array_values( $replace ), $id );
1103 if ( !preg_match( '/^[a-zA-Z]/', $id )
1104 && !in_array( 'noninitial', $options ) ) {
1105 // Initial character must be a letter!
1112 * Given a value, escape it so that it can be used as a CSS class and
1115 * @todo For extra validity, input should be validated UTF-8.
1117 * @see http://www.w3.org/TR/CSS21/syndata.html Valid characters/format
1119 * @param $class String
1122 static function escapeClass( $class ) {
1123 // Convert ugly stuff to underscores and kill underscores in ugly places
1124 return rtrim(preg_replace(
1125 array('/(^[0-9\\-])|[\\x00-\\x20!"#$%&\'()*+,.\\/:;<=>?@[\\]^`{|}~]|\\xC2\\xA0/','/_+/'),
1131 * Given HTML input, escape with htmlspecialchars but un-escape entites.
1132 * This allows (generally harmless) entities like   to survive.
1134 * @param $html String to escape
1135 * @return String: escaped input
1137 static function escapeHtmlAllowEntities( $html ) {
1138 $html = Sanitizer
::decodeCharReferences( $html );
1139 # It seems wise to escape ' as well as ", as a matter of course. Can't
1141 $html = htmlspecialchars( $html, ENT_QUOTES
);
1146 * Regex replace callback for armoring links against further processing.
1147 * @param $matches Array
1150 private static function armorLinksCallback( $matches ) {
1151 return str_replace( ':', ':', $matches[1] );
1155 * Return an associative array of attribute names and values from
1156 * a partial tag string. Attribute names are forces to lowercase,
1157 * character references are decoded to UTF-8 text.
1159 * @param $text String
1162 public static function decodeTagAttributes( $text ) {
1163 if( trim( $text ) == '' ) {
1169 if( !preg_match_all(
1170 self
::getAttribsRegex(),
1173 PREG_SET_ORDER
) ) {
1177 foreach( $pairs as $set ) {
1178 $attribute = strtolower( $set[1] );
1179 $value = Sanitizer
::getTagAttributeCallback( $set );
1181 // Normalize whitespace
1182 $value = preg_replace( '/[\t\r\n ]+/', ' ', $value );
1183 $value = trim( $value );
1185 // Decode character references
1186 $attribs[$attribute] = Sanitizer
::decodeCharReferences( $value );
1192 * Pick the appropriate attribute value from a match set from the
1193 * attribs regex matches.
1198 private static function getTagAttributeCallback( $set ) {
1199 if( isset( $set[6] ) ) {
1200 # Illegal #XXXXXX color with no quotes.
1202 } elseif( isset( $set[5] ) ) {
1205 } elseif( isset( $set[4] ) ) {
1208 } elseif( isset( $set[3] ) ) {
1211 } elseif( !isset( $set[2] ) ) {
1212 # In XHTML, attributes must have a value.
1213 # For 'reduced' form, return explicitly the attribute name here.
1216 throw new MWException( "Tag conditions not met. This should never happen and is a bug." );
1221 * Normalize whitespace and character references in an XML source-
1222 * encoded text for an attribute value.
1224 * See http://www.w3.org/TR/REC-xml/#AVNormalize for background,
1225 * but note that we're not returning the value, but are returning
1226 * XML source fragments that will be slapped into output.
1228 * @param $text String
1231 private static function normalizeAttributeValue( $text ) {
1232 return str_replace( '"', '"',
1233 self
::normalizeWhitespace(
1234 Sanitizer
::normalizeCharReferences( $text ) ) );
1238 * @param $text string
1241 private static function normalizeWhitespace( $text ) {
1242 return preg_replace(
1243 '/\r\n|[\x20\x0d\x0a\x09]/',
1249 * Normalizes whitespace in a section name, such as might be returned
1250 * by Parser::stripSectionName(), for use in the id's that are used for
1253 * @param $section String
1256 static function normalizeSectionNameWhitespace( $section ) {
1257 return trim( preg_replace( '/[ _]+/', ' ', $section ) );
1261 * Ensure that any entities and character references are legal
1262 * for XML and XHTML specifically. Any stray bits will be
1263 * &-escaped to result in a valid text fragment.
1265 * a. named char refs can only be < > & ", others are
1266 * numericized (this way we're well-formed even without a DTD)
1267 * b. any numeric char refs must be legal chars, not invalid or forbidden
1268 * c. use &#x, not &#X
1269 * d. fix or reject non-valid attributes
1271 * @param $text String
1275 static function normalizeCharReferences( $text ) {
1276 return preg_replace_callback(
1277 self
::CHAR_REFS_REGEX
,
1278 array( 'Sanitizer', 'normalizeCharReferencesCallback' ),
1282 * @param $matches String
1285 static function normalizeCharReferencesCallback( $matches ) {
1287 if( $matches[1] != '' ) {
1288 $ret = Sanitizer
::normalizeEntity( $matches[1] );
1289 } elseif( $matches[2] != '' ) {
1290 $ret = Sanitizer
::decCharReference( $matches[2] );
1291 } elseif( $matches[3] != '' ) {
1292 $ret = Sanitizer
::hexCharReference( $matches[3] );
1294 if( is_null( $ret ) ) {
1295 return htmlspecialchars( $matches[0] );
1302 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1303 * return the equivalent numeric entity reference (except for the core <
1304 * > & "). If the entity is a MediaWiki-specific alias, returns
1305 * the HTML equivalent. Otherwise, returns HTML-escaped text of
1306 * pseudo-entity source (eg &foo;)
1308 * @param $name String
1311 static function normalizeEntity( $name ) {
1312 if ( isset( self
::$htmlEntityAliases[$name] ) ) {
1313 return '&' . self
::$htmlEntityAliases[$name] . ';';
1314 } elseif ( in_array( $name,
1315 array( 'lt', 'gt', 'amp', 'quot' ) ) ) {
1317 } elseif ( isset( self
::$htmlEntities[$name] ) ) {
1318 return '&#' . self
::$htmlEntities[$name] . ';';
1320 return "&$name;";
1326 * @return null|string
1328 static function decCharReference( $codepoint ) {
1329 $point = intval( $codepoint );
1330 if( Sanitizer
::validateCodepoint( $point ) ) {
1331 return sprintf( '&#%d;', $point );
1339 * @return null|string
1341 static function hexCharReference( $codepoint ) {
1342 $point = hexdec( $codepoint );
1343 if( Sanitizer
::validateCodepoint( $point ) ) {
1344 return sprintf( '&#x%x;', $point );
1351 * Returns true if a given Unicode codepoint is a valid character in XML.
1352 * @param $codepoint Integer
1355 private static function validateCodepoint( $codepoint ) {
1356 return ($codepoint == 0x09)
1357 ||
($codepoint == 0x0a)
1358 ||
($codepoint == 0x0d)
1359 ||
($codepoint >= 0x20 && $codepoint <= 0xd7ff)
1360 ||
($codepoint >= 0xe000 && $codepoint <= 0xfffd)
1361 ||
($codepoint >= 0x10000 && $codepoint <= 0x10ffff);
1365 * Decode any character references, numeric or named entities,
1366 * in the text and return a UTF-8 string.
1368 * @param $text String
1371 public static function decodeCharReferences( $text ) {
1372 return preg_replace_callback(
1373 self
::CHAR_REFS_REGEX
,
1374 array( 'Sanitizer', 'decodeCharReferencesCallback' ),
1379 * Decode any character references, numeric or named entities,
1380 * in the next and normalize the resulting string. (bug 14952)
1382 * This is useful for page titles, not for text to be displayed,
1383 * MediaWiki allows HTML entities to escape normalization as a feature.
1385 * @param $text String (already normalized, containing entities)
1386 * @return String (still normalized, without entities)
1388 public static function decodeCharReferencesAndNormalize( $text ) {
1390 $text = preg_replace_callback(
1391 self
::CHAR_REFS_REGEX
,
1392 array( 'Sanitizer', 'decodeCharReferencesCallback' ),
1393 $text, /* limit */ -1, $count );
1396 return $wgContLang->normalize( $text );
1403 * @param $matches String
1406 static function decodeCharReferencesCallback( $matches ) {
1407 if( $matches[1] != '' ) {
1408 return Sanitizer
::decodeEntity( $matches[1] );
1409 } elseif( $matches[2] != '' ) {
1410 return Sanitizer
::decodeChar( intval( $matches[2] ) );
1411 } elseif( $matches[3] != '' ) {
1412 return Sanitizer
::decodeChar( hexdec( $matches[3] ) );
1414 # Last case should be an ampersand by itself
1419 * Return UTF-8 string for a codepoint if that is a valid
1420 * character reference, otherwise U+FFFD REPLACEMENT CHARACTER.
1421 * @param $codepoint Integer
1425 static function decodeChar( $codepoint ) {
1426 if( Sanitizer
::validateCodepoint( $codepoint ) ) {
1427 return codepointToUtf8( $codepoint );
1429 return UTF8_REPLACEMENT
;
1434 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1435 * return the UTF-8 encoding of that character. Otherwise, returns
1436 * pseudo-entity source (eg &foo;)
1438 * @param $name String
1441 static function decodeEntity( $name ) {
1442 if ( isset( self
::$htmlEntityAliases[$name] ) ) {
1443 $name = self
::$htmlEntityAliases[$name];
1445 if( isset( self
::$htmlEntities[$name] ) ) {
1446 return codepointToUtf8( self
::$htmlEntities[$name] );
1453 * Fetch the whitelist of acceptable attributes for a given element name.
1455 * @param $element String
1458 static function attributeWhitelist( $element ) {
1460 if( !isset( $list ) ) {
1461 $list = Sanitizer
::setupAttributeWhitelist();
1463 return isset( $list[$element] )
1469 * Foreach array key (an allowed HTML element), return an array
1470 * of allowed attributes
1473 static function setupAttributeWhitelist() {
1474 global $wgAllowRdfaAttributes, $wgHtml5, $wgAllowMicrodataAttributes;
1476 $common = array( 'id', 'class', 'lang', 'dir', 'title', 'style' );
1478 if ( $wgAllowRdfaAttributes ) {
1479 #RDFa attributes as specified in section 9 of http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014
1480 $common = array_merge( $common, array(
1481 'about', 'property', 'resource', 'datatype', 'typeof',
1485 if ( $wgHtml5 && $wgAllowMicrodataAttributes ) {
1486 # add HTML5 microdata tages as pecified by http://www.whatwg.org/specs/web-apps/current-work/multipage/microdata.html#the-microdata-model
1487 $common = array_merge( $common, array(
1488 'itemid', 'itemprop', 'itemref', 'itemscope', 'itemtype'
1492 $block = array_merge( $common, array( 'align' ) );
1493 $tablealign = array( 'align', 'char', 'charoff', 'valign' );
1494 $tablecell = array( 'abbr',
1500 'nowrap', # deprecated
1501 'width', # deprecated
1502 'height', # deprecated
1503 'bgcolor' # deprecated
1506 # Numbers refer to sections in HTML 4.01 standard describing the element.
1507 # See: http://www.w3.org/TR/html4/
1508 $whitelist = array (
1511 'center' => $common, # deprecated
1512 'span' => $block, # ??
1530 'strong' => $common,
1541 'blockquote' => array_merge( $common, array( 'cite' ) ),
1552 'br' => array( 'id', 'class', 'title', 'style', 'clear' ),
1555 'pre' => array_merge( $common, array( 'width' ) ),
1558 'ins' => array_merge( $common, array( 'cite', 'datetime' ) ),
1559 'del' => array_merge( $common, array( 'cite', 'datetime' ) ),
1562 'ul' => array_merge( $common, array( 'type' ) ),
1563 'ol' => array_merge( $common, array( 'type', 'start' ) ),
1564 'li' => array_merge( $common, array( 'type', 'value' ) ),
1572 'table' => array_merge( $common,
1573 array( 'summary', 'width', 'border', 'frame',
1574 'rules', 'cellspacing', 'cellpadding',
1579 'caption' => array_merge( $common, array( 'align' ) ),
1582 'thead' => array_merge( $common, $tablealign ),
1583 'tfoot' => array_merge( $common, $tablealign ),
1584 'tbody' => array_merge( $common, $tablealign ),
1587 'colgroup' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
1588 'col' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
1591 'tr' => array_merge( $common, array( 'bgcolor' ), $tablealign ),
1594 'td' => array_merge( $common, $tablecell, $tablealign ),
1595 'th' => array_merge( $common, $tablecell, $tablealign ),
1598 'a' => array_merge( $common, array( 'href', 'rel', 'rev' ) ), # rel/rev esp. for RDFa
1601 # Not usually allowed, but may be used for extension-style hooks
1602 # such as <math> when it is rasterized, or if $wgAllowImageTag is
1604 'img' => array_merge( $common, array( 'alt', 'src', 'width', 'height' ) ),
1612 'strike' => $common,
1617 'font' => array_merge( $common, array( 'size', 'color', 'face' ) ),
1621 'hr' => array_merge( $common, array( 'noshade', 'size', 'width' ) ),
1623 # XHTML Ruby annotation text module, simple ruby only.
1624 # http://www.w3c.org/TR/ruby/
1629 'rt' => $common, #array_merge( $common, array( 'rbspan' ) ),
1632 # MathML root element, where used for extensions
1633 # 'title' may not be 100% valid here; it's XHTML
1634 # http://www.w3.org/TR/REC-MathML/
1635 'math' => array( 'class', 'style', 'id', 'title' ),
1641 * Take a fragment of (potentially invalid) HTML and return
1642 * a version with any tags removed, encoded as plain text.
1644 * Warning: this return value must be further escaped for literal
1645 * inclusion in HTML output as of 1.10!
1647 * @param $text String: HTML fragment
1650 static function stripAllTags( $text ) {
1652 $text = StringUtils
::delimiterReplace( '<', '>', '', $text );
1654 # Normalize &entities and whitespace
1655 $text = self
::decodeCharReferences( $text );
1656 $text = self
::normalizeWhitespace( $text );
1662 * Hack up a private DOCTYPE with HTML's standard entity declarations.
1663 * PHP 4 seemed to know these if you gave it an HTML doctype, but
1666 * Use for passing XHTML fragments to PHP's XML parsing functions
1670 static function hackDocType() {
1671 $out = "<!DOCTYPE html [\n";
1672 foreach( self
::$htmlEntities as $entity => $codepoint ) {
1673 $out .= "<!ENTITY $entity \"&#$codepoint;\">";
1680 * @param $url string
1681 * @return mixed|string
1683 static function cleanUrl( $url ) {
1684 # Normalize any HTML entities in input. They will be
1685 # re-escaped by makeExternalLink().
1686 $url = Sanitizer
::decodeCharReferences( $url );
1688 # Escape any control characters introduced by the above step
1689 $url = preg_replace_callback( '/[\][<>"\\x00-\\x20\\x7F\|]/',
1690 array( __CLASS__
, 'cleanUrlCallback' ), $url );
1692 # Validate hostname portion
1694 if( preg_match( '!^([^:]+:)(//[^/]+)?(.*)$!iD', $url, $matches ) ) {
1695 list( /* $whole */, $protocol, $host, $rest ) = $matches;
1697 // Characters that will be ignored in IDNs.
1698 // http://tools.ietf.org/html/3454#section-3.1
1699 // Strip them before further processing so blacklists and such work.
1701 \\s| # general whitespace
1702 \xc2\xad| # 00ad SOFT HYPHEN
1703 \xe1\xa0\x86| # 1806 MONGOLIAN TODO SOFT HYPHEN
1704 \xe2\x80\x8b| # 200b ZERO WIDTH SPACE
1705 \xe2\x81\xa0| # 2060 WORD JOINER
1706 \xef\xbb\xbf| # feff ZERO WIDTH NO-BREAK SPACE
1707 \xcd\x8f| # 034f COMBINING GRAPHEME JOINER
1708 \xe1\xa0\x8b| # 180b MONGOLIAN FREE VARIATION SELECTOR ONE
1709 \xe1\xa0\x8c| # 180c MONGOLIAN FREE VARIATION SELECTOR TWO
1710 \xe1\xa0\x8d| # 180d MONGOLIAN FREE VARIATION SELECTOR THREE
1711 \xe2\x80\x8c| # 200c ZERO WIDTH NON-JOINER
1712 \xe2\x80\x8d| # 200d ZERO WIDTH JOINER
1713 [\xef\xb8\x80-\xef\xb8\x8f] # fe00-fe0f VARIATION SELECTOR-1-16
1716 $host = preg_replace( $strip, '', $host );
1718 // @todo FIXME: Validate hostnames here
1720 return $protocol . $host . $rest;
1727 * @param $matches array
1730 static function cleanUrlCallback( $matches ) {
1731 return urlencode( $matches[0] );
1735 * Does a string look like an e-mail address?
1737 * This validates an email address using an HTML5 specification found at:
1738 * http://www.whatwg.org/specs/web-apps/current-work/multipage/states-of-the-type-attribute.html#valid-e-mail-address
1739 * Which as of 2011-01-24 says:
1741 * A valid e-mail address is a string that matches the ABNF production
1742 * 1*( atext / "." ) "@" ldh-str *( "." ldh-str ) where atext is defined
1743 * in RFC 5322 section 3.2.3, and ldh-str is defined in RFC 1034 section
1746 * This function is an implementation of the specification as requested in
1749 * Client-side forms will use the same standard validation rules via JS or
1750 * HTML 5 validation; additional restrictions can be enforced server-side
1751 * by extensions via the 'isValidEmailAddr' hook.
1753 * Note that this validation doesn't 100% match RFC 2822, but is believed
1754 * to be liberal enough for wide use. Some invalid addresses will still
1755 * pass validation here.
1759 * @param $addr String E-mail address
1762 public static function validateEmail( $addr ) {
1764 if( !wfRunHooks( 'isValidEmailAddr', array( $addr, &$result ) ) ) {
1768 // Please note strings below are enclosed in brackets [], this make the
1769 // hyphen "-" a range indicator. Hence it is double backslashed below.
1771 $rfc5322_atext = "a-z0-9!#$%&'*+\\-\/=?^_`{|}~" ;
1772 $rfc1034_ldh_str = "a-z0-9\\-" ;
1774 $HTML5_email_regexp = "/
1776 [$rfc5322_atext\\.]+ # user part which is liberal :p
1778 [$rfc1034_ldh_str]+ # First domain part
1779 (\\.[$rfc1034_ldh_str]+)* # Following part prefixed with a dot
1781 /ix" ; // case Insensitive, eXtended
1783 return (bool) preg_match( $HTML5_email_regexp, $addr );