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fix notice warning in some configs
[mediawiki.git] / includes / Sanitizer.php
blobdd59f44f6d8e4180cc82117b96947f848e9671e2
1 <?php
2
3 /**
4 * (X)HTML sanitizer for MediaWiki
5 *
6 * Copyright (C) 2002-2005 Brion Vibber <brion@pobox.com> et al
7 * http://www.mediawiki.org/
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 * http://www.gnu.org/copyleft/gpl.html
23 *
24 * @package MediaWiki
25 * @subpackage Parser
26 */
27
28 /**
29 * Regular expression to match various types of character references in
30 * Sanitizer::normalizeCharReferences and Sanitizer::decodeCharReferences
31 */
32 define( 'MW_CHAR_REFS_REGEX',
33 '/&([A-Za-z0-9]+);
34 |&\#([0-9]+);
35 |&\#x([0-9A-Za-z]+);
36 |&\#X([0-9A-Za-z]+);
37 |(&)/x' );
38
39 /**
40 * Regular expression to match HTML/XML attribute pairs within a tag.
41 * Allows some... latitude.
42 * Used in Sanitizer::fixTagAttributes and Sanitizer::decodeTagAttributes
43 */
44 $attrib = '[A-Za-z0-9]';
45 $space = '[\x09\x0a\x0d\x20]';
46 define( 'MW_ATTRIBS_REGEX',
47 "/(?:^|$space)($attrib+)
48 ($space*=$space*
49 (?:
50 # The attribute value: quoted or alone
51 \"([^<\"]*)\"
52 | '([^<']*)'
53 | ([a-zA-Z0-9!#$%&()*,\\-.\\/:;<>?@[\\]^_`{|}~]+)
54 | (\#[0-9a-fA-F]+) # Technically wrong, but lots of
55 # colors are specified like this.
56 # We'll be normalizing it.
57 )
58 )?(?=$space|\$)/sx" );
59
60 /**
61 * List of all named character entities defined in HTML 4.01
62 * http://www.w3.org/TR/html4/sgml/entities.html
63 * @access private
64 */
65 global $wgHtmlEntities;
66 $wgHtmlEntities = array(
67 'Aacute' => 193,
68 'aacute' => 225,
69 'Acirc' => 194,
70 'acirc' => 226,
71 'acute' => 180,
72 'AElig' => 198,
73 'aelig' => 230,
74 'Agrave' => 192,
75 'agrave' => 224,
76 'alefsym' => 8501,
77 'Alpha' => 913,
78 'alpha' => 945,
79 'amp' => 38,
80 'and' => 8743,
81 'ang' => 8736,
82 'Aring' => 197,
83 'aring' => 229,
84 'asymp' => 8776,
85 'Atilde' => 195,
86 'atilde' => 227,
87 'Auml' => 196,
88 'auml' => 228,
89 'bdquo' => 8222,
90 'Beta' => 914,
91 'beta' => 946,
92 'brvbar' => 166,
93 'bull' => 8226,
94 'cap' => 8745,
95 'Ccedil' => 199,
96 'ccedil' => 231,
97 'cedil' => 184,
98 'cent' => 162,
99 'Chi' => 935,
100 'chi' => 967,
101 'circ' => 710,
102 'clubs' => 9827,
103 'cong' => 8773,
104 'copy' => 169,
105 'crarr' => 8629,
106 'cup' => 8746,
107 'curren' => 164,
108 'dagger' => 8224,
109 'Dagger' => 8225,
110 'darr' => 8595,
111 'dArr' => 8659,
112 'deg' => 176,
113 'Delta' => 916,
114 'delta' => 948,
115 'diams' => 9830,
116 'divide' => 247,
117 'Eacute' => 201,
118 'eacute' => 233,
119 'Ecirc' => 202,
120 'ecirc' => 234,
121 'Egrave' => 200,
122 'egrave' => 232,
123 'empty' => 8709,
124 'emsp' => 8195,
125 'ensp' => 8194,
126 'Epsilon' => 917,
127 'epsilon' => 949,
128 'equiv' => 8801,
129 'Eta' => 919,
130 'eta' => 951,
131 'ETH' => 208,
132 'eth' => 240,
133 'Euml' => 203,
134 'euml' => 235,
135 'euro' => 8364,
136 'exist' => 8707,
137 'fnof' => 402,
138 'forall' => 8704,
139 'frac12' => 189,
140 'frac14' => 188,
141 'frac34' => 190,
142 'frasl' => 8260,
143 'Gamma' => 915,
144 'gamma' => 947,
145 'ge' => 8805,
146 'gt' => 62,
147 'harr' => 8596,
148 'hArr' => 8660,
149 'hearts' => 9829,
150 'hellip' => 8230,
151 'Iacute' => 205,
152 'iacute' => 237,
153 'Icirc' => 206,
154 'icirc' => 238,
155 'iexcl' => 161,
156 'Igrave' => 204,
157 'igrave' => 236,
158 'image' => 8465,
159 'infin' => 8734,
160 'int' => 8747,
161 'Iota' => 921,
162 'iota' => 953,
163 'iquest' => 191,
164 'isin' => 8712,
165 'Iuml' => 207,
166 'iuml' => 239,
167 'Kappa' => 922,
168 'kappa' => 954,
169 'Lambda' => 923,
170 'lambda' => 955,
171 'lang' => 9001,
172 'laquo' => 171,
173 'larr' => 8592,
174 'lArr' => 8656,
175 'lceil' => 8968,
176 'ldquo' => 8220,
177 'le' => 8804,
178 'lfloor' => 8970,
179 'lowast' => 8727,
180 'loz' => 9674,
181 'lrm' => 8206,
182 'lsaquo' => 8249,
183 'lsquo' => 8216,
184 'lt' => 60,
185 'macr' => 175,
186 'mdash' => 8212,
187 'micro' => 181,
188 'middot' => 183,
189 'minus' => 8722,
190 'Mu' => 924,
191 'mu' => 956,
192 'nabla' => 8711,
193 'nbsp' => 160,
194 'ndash' => 8211,
195 'ne' => 8800,
196 'ni' => 8715,
197 'not' => 172,
198 'notin' => 8713,
199 'nsub' => 8836,
200 'Ntilde' => 209,
201 'ntilde' => 241,
202 'Nu' => 925,
203 'nu' => 957,
204 'Oacute' => 211,
205 'oacute' => 243,
206 'Ocirc' => 212,
207 'ocirc' => 244,
208 'OElig' => 338,
209 'oelig' => 339,
210 'Ograve' => 210,
211 'ograve' => 242,
212 'oline' => 8254,
213 'Omega' => 937,
214 'omega' => 969,
215 'Omicron' => 927,
216 'omicron' => 959,
217 'oplus' => 8853,
218 'or' => 8744,
219 'ordf' => 170,
220 'ordm' => 186,
221 'Oslash' => 216,
222 'oslash' => 248,
223 'Otilde' => 213,
224 'otilde' => 245,
225 'otimes' => 8855,
226 'Ouml' => 214,
227 'ouml' => 246,
228 'para' => 182,
229 'part' => 8706,
230 'permil' => 8240,
231 'perp' => 8869,
232 'Phi' => 934,
233 'phi' => 966,
234 'Pi' => 928,
235 'pi' => 960,
236 'piv' => 982,
237 'plusmn' => 177,
238 'pound' => 163,
239 'prime' => 8242,
240 'Prime' => 8243,
241 'prod' => 8719,
242 'prop' => 8733,
243 'Psi' => 936,
244 'psi' => 968,
245 'quot' => 34,
246 'radic' => 8730,
247 'rang' => 9002,
248 'raquo' => 187,
249 'rarr' => 8594,
250 'rArr' => 8658,
251 'rceil' => 8969,
252 'rdquo' => 8221,
253 'real' => 8476,
254 'reg' => 174,
255 'rfloor' => 8971,
256 'Rho' => 929,
257 'rho' => 961,
258 'rlm' => 8207,
259 'rsaquo' => 8250,
260 'rsquo' => 8217,
261 'sbquo' => 8218,
262 'Scaron' => 352,
263 'scaron' => 353,
264 'sdot' => 8901,
265 'sect' => 167,
266 'shy' => 173,
267 'Sigma' => 931,
268 'sigma' => 963,
269 'sigmaf' => 962,
270 'sim' => 8764,
271 'spades' => 9824,
272 'sub' => 8834,
273 'sube' => 8838,
274 'sum' => 8721,
275 'sup' => 8835,
276 'sup1' => 185,
277 'sup2' => 178,
278 'sup3' => 179,
279 'supe' => 8839,
280 'szlig' => 223,
281 'Tau' => 932,
282 'tau' => 964,
283 'there4' => 8756,
284 'Theta' => 920,
285 'theta' => 952,
286 'thetasym' => 977,
287 'thinsp' => 8201,
288 'THORN' => 222,
289 'thorn' => 254,
290 'tilde' => 732,
291 'times' => 215,
292 'trade' => 8482,
293 'Uacute' => 218,
294 'uacute' => 250,
295 'uarr' => 8593,
296 'uArr' => 8657,
297 'Ucirc' => 219,
298 'ucirc' => 251,
299 'Ugrave' => 217,
300 'ugrave' => 249,
301 'uml' => 168,
302 'upsih' => 978,
303 'Upsilon' => 933,
304 'upsilon' => 965,
305 'Uuml' => 220,
306 'uuml' => 252,
307 'weierp' => 8472,
308 'Xi' => 926,
309 'xi' => 958,
310 'Yacute' => 221,
311 'yacute' => 253,
312 'yen' => 165,
313 'Yuml' => 376,
314 'yuml' => 255,
315 'Zeta' => 918,
316 'zeta' => 950,
317 'zwj' => 8205,
318 'zwnj' => 8204 );
319
320 class Sanitizer {
321 /**
322 * Cleans up HTML, removes dangerous tags and attributes, and
323 * removes HTML comments
324 * @access private
325 * @param string $text
326 * @param callback $processCallback to do any variable or parameter replacements in HTML attribute values
327 * @param array $args for the processing callback
328 * @return string
329 */
330 function removeHTMLtags( $text, $processCallback = null, $args = array() ) {
331 global $wgUseTidy, $wgUserHtml;
332 $fname = 'Parser::removeHTMLtags';
333 wfProfileIn( $fname );
334
335 if( $wgUserHtml ) {
336 $htmlpairs = array( # Tags that must be closed
337 'b', 'del', 'i', 'ins', 'u', 'font', 'big', 'small', 'sub', 'sup', 'h1',
338 'h2', 'h3', 'h4', 'h5', 'h6', 'cite', 'code', 'em', 's',
339 'strike', 'strong', 'tt', 'var', 'div', 'center',
340 'blockquote', 'ol', 'ul', 'dl', 'table', 'caption', 'pre',
341 'ruby', 'rt' , 'rb' , 'rp', 'p', 'span'
342 );
343 $htmlsingle = array(
344 'br', 'hr', 'li', 'dt', 'dd'
345 );
346 $htmlsingleonly = array( # Elements that cannot have close tags
347 'br', 'hr'
348 );
349 $htmlnest = array( # Tags that can be nested--??
350 'table', 'tr', 'td', 'th', 'div', 'blockquote', 'ol', 'ul',
351 'dl', 'font', 'big', 'small', 'sub', 'sup', 'span'
352 );
353 $tabletags = array( # Can only appear inside table
354 'td', 'th', 'tr'
355 );
356 } else {
357 $htmlpairs = array();
358 $htmlsingle = array();
359 $htmlnest = array();
360 $tabletags = array();
361 }
362
363 $htmlsingle = array_merge( $tabletags, $htmlsingle );
364 $htmlelements = array_merge( $htmlsingle, $htmlpairs );
365
366 # Remove HTML comments
367 $text = Sanitizer::removeHTMLcomments( $text );
368
369 $bits = explode( '<', $text );
370 $text = array_shift( $bits );
371 if(!$wgUseTidy) {
372 $tagstack = array(); $tablestack = array();
373 foreach ( $bits as $x ) {
374 $prev = error_reporting( E_ALL & ~( E_NOTICE | E_WARNING ) );
375 preg_match( '/^(\\/?)(\\w+)([^>]*?)(\\/{0,1}>)([^<]*)$/',
376 $x, $regs );
377 list( $qbar, $slash, $t, $params, $brace, $rest ) = $regs;
378 error_reporting( $prev );
379
380 $badtag = 0 ;
381 if ( in_array( $t = strtolower( $t ), $htmlelements ) ) {
382 # Check our stack
383 if ( $slash ) {
384 # Closing a tag...
385 if( in_array( $t, $htmlsingleonly ) ) {
386 $badtag = 1;
387 } elseif( !in_array( $t, $htmlsingle ) &&
388 ( $ot = @array_pop( $tagstack ) ) != $t ) {
389 @array_push( $tagstack, $ot );
390 $badtag = 1;
391 } else {
392 if ( $t == 'table' ) {
393 $tagstack = array_pop( $tablestack );
394 }
395 $newparams = '';
396 }
397 } else {
398 # Keep track for later
399 if ( in_array( $t, $tabletags ) &&
400 ! in_array( 'table', $tagstack ) ) {
401 $badtag = 1;
402 } else if ( in_array( $t, $tagstack ) &&
403 ! in_array ( $t , $htmlnest ) ) {
404 $badtag = 1 ;
405 } elseif( in_array( $t, $htmlsingleonly ) ) {
406 # Hack to force empty tag for uncloseable elements
407 $brace = '/>';
408 } else if ( ! in_array( $t, $htmlsingle ) ) {
409 if ( $t == 'table' ) {
410 array_push( $tablestack, $tagstack );
411 $tagstack = array();
412 }
413 array_push( $tagstack, $t );
414 }
415
416 # Replace any variables or template parameters with
417 # plaintext results.
418 if( is_callable( $processCallback ) ) {
419 call_user_func_array( $processCallback, array( &$params, $args ) );
420 }
421
422 # Strip non-approved attributes from the tag
423 $newparams = Sanitizer::fixTagAttributes( $params, $t );
424 }
425 if ( ! $badtag ) {
426 $rest = str_replace( '>', '&gt;', $rest );
427 $close = ( $brace == '/>' ) ? ' /' : '';
428 $text .= "<$slash$t$newparams$close>$rest";
429 continue;
430 }
431 }
432 $text .= '&lt;' . str_replace( '>', '&gt;', $x);
433 }
434 # Close off any remaining tags
435 while ( is_array( $tagstack ) && ($t = array_pop( $tagstack )) ) {
436 $text .= "</$t>\n";
437 if ( $t == 'table' ) { $tagstack = array_pop( $tablestack ); }
438 }
439 } else {
440 # this might be possible using tidy itself
441 foreach ( $bits as $x ) {
442 preg_match( '/^(\\/?)(\\w+)([^>]*?)(\\/{0,1}>)([^<]*)$/',
443 $x, $regs );
444 @list( $qbar, $slash, $t, $params, $brace, $rest ) = $regs;
445 if ( in_array( $t = strtolower( $t ), $htmlelements ) ) {
446 if( is_callable( $processCallback ) ) {
447 call_user_func_array( $processCallback, array( &$params, $args ) );
448 }
449 $newparams = Sanitizer::fixTagAttributes( $params, $t );
450 $rest = str_replace( '>', '&gt;', $rest );
451 $text .= "<$slash$t$newparams$brace$rest";
452 } else {
453 $text .= '&lt;' . str_replace( '>', '&gt;', $x);
454 }
455 }
456 }
457 wfProfileOut( $fname );
458 return $text;
459 }
460
461 /**
462 * Remove '<!--', '-->', and everything between.
463 * To avoid leaving blank lines, when a comment is both preceded
464 * and followed by a newline (ignoring spaces), trim leading and
465 * trailing spaces and one of the newlines.
466 *
467 * @access private
468 * @param string $text
469 * @return string
470 */
471 function removeHTMLcomments( $text ) {
472 $fname='Parser::removeHTMLcomments';
473 wfProfileIn( $fname );
474 while (($start = strpos($text, '<!--')) !== false) {
475 $end = strpos($text, '-->', $start + 4);
476 if ($end === false) {
477 # Unterminated comment; bail out
478 break;
479 }
480
481 $end += 3;
482
483 # Trim space and newline if the comment is both
484 # preceded and followed by a newline
485 $spaceStart = max($start - 1, 0);
486 $spaceLen = $end - $spaceStart;
487 while (substr($text, $spaceStart, 1) === ' ' && $spaceStart > 0) {
488 $spaceStart--;
489 $spaceLen++;
490 }
491 while (substr($text, $spaceStart + $spaceLen, 1) === ' ')
492 $spaceLen++;
493 if (substr($text, $spaceStart, 1) === "\n" and substr($text, $spaceStart + $spaceLen, 1) === "\n") {
494 # Remove the comment, leading and trailing
495 # spaces, and leave only one newline.
496 $text = substr_replace($text, "\n", $spaceStart, $spaceLen + 1);
497 }
498 else {
499 # Remove just the comment.
500 $text = substr_replace($text, '', $start, $end - $start);
501 }
502 }
503 wfProfileOut( $fname );
504 return $text;
505 }
506
507 /**
508 * Take a tag soup fragment listing an HTML element's attributes
509 * and normalize it to well-formed XML, discarding unwanted attributes.
510 *
511 * - Normalizes attribute names to lowercase
512 * - Discards attributes not on a whitelist for the given element
513 * - Turns broken or invalid entities into plaintext
514 * - Double-quotes all attribute values
515 * - Attributes without values are given the name as attribute
516 * - Double attributes are discarded
517 * - Unsafe style attributes are discarded
518 * - Prepends space if there are attributes.
519 *
520 * @param string $text
521 * @param string $element
522 * @return string
523 *
524 * @todo Check for legal values where the DTD limits things.
525 * @todo Check for unique id attribute :P
526 */
527 function fixTagAttributes( $text, $element ) {
528 if( trim( $text ) == '' ) {
529 return '';
530 }
531
532 # Unquoted attribute
533 # Since we quote this later, this can be anything distinguishable
534 # from the end of the attribute
535 if( !preg_match_all(
536 MW_ATTRIBS_REGEX,
537 $text,
538 $pairs,
539 PREG_SET_ORDER ) ) {
540 return '';
541 }
542
543 $whitelist = array_flip( Sanitizer::attributeWhitelist( $element ) );
544 $attribs = array();
545 foreach( $pairs as $set ) {
546 $attribute = strtolower( $set[1] );
547 if( !isset( $whitelist[$attribute] ) ) {
548 continue;
549 }
550
551 $raw = Sanitizer::getTagAttributeCallback( $set );
552 $value = Sanitizer::normalizeAttributeValue( $raw );
553
554 # Strip javascript "expression" from stylesheets.
555 # http://msdn.microsoft.com/workshop/author/dhtml/overview/recalc.asp
556 if( $attribute == 'style' && preg_match(
557 '/(expression|tps*:\/\/|url\\s*\().*/is',
558 Sanitizer::decodeCharReferences( $value ) ) ) {
559 # haxx0r
560 continue;
561 }
562
563 # Templates and links may be expanded in later parsing,
564 # creating invalid or dangerous output. Suppress this.
565 $value = strtr( $value, array(
566 '{' => '&#123;',
567 '[' => '&#91;',
568 "''" => '&#39;&#39;',
569 'ISBN' => '&#73;SBN',
570 'RFC' => '&#82;FC',
571 'PMID' => '&#80;MID',
572 ) );
573 $value = preg_replace(
574 '/(' . URL_PROTOCOLS . '):/',
575 '\\1&#58;', $value );
576
577 // If this attribute was previously set, override it.
578 // Output should only have one attribute of each name.
579 $attribs[$attribute] = "$attribute=\"$value\"";
580 }
581 if( empty( $attribs ) ) {
582 return '';
583 } else {
584 return ' ' . implode( ' ', $attribs );
585 }
586 }
587
588 /**
589 * Return an associative array of attribute names and values from
590 * a partial tag string. Attribute names are forces to lowercase,
591 * character references are decoded to UTF-8 text.
592 *
593 * @param string
594 * @return array
595 */
596 function decodeTagAttributes( $text ) {
597 $attribs = array();
598
599 if( trim( $text ) == '' ) {
600 return $attribs;
601 }
602
603 if( !preg_match_all(
604 MW_ATTRIBS_REGEX,
605 $text,
606 $pairs,
607 PREG_SET_ORDER ) ) {
608 return $attribs;
609 }
610
611 foreach( $pairs as $set ) {
612 $attribute = strtolower( $set[1] );
613 $value = Sanitizer::getTagAttributeCallback( $set );
614 $attribs[$attribute] = Sanitizer::decodeCharReferences( $value );
615 }
616 return $attribs;
617 }
618
619 /**
620 * Pick the appropriate attribute value from a match set from the
621 * MW_ATTRIBS_REGEX matches.
622 *
623 * @param array $set
624 * @return string
625 * @access private
626 */
627 function getTagAttributeCallback( $set ) {
628 if( isset( $set[6] ) ) {
629 # Illegal #XXXXXX color with no quotes.
630 return $set[6];
631 } elseif( isset( $set[5] ) ) {
632 # No quotes.
633 return $set[5];
634 } elseif( isset( $set[4] ) ) {
635 # Single-quoted
636 return $set[4];
637 } elseif( isset( $set[3] ) ) {
638 # Double-quoted
639 return $set[3];
640 } elseif( !isset( $set[2] ) ) {
641 # In XHTML, attributes must have a value.
642 # For 'reduced' form, return explicitly the attribute name here.
643 return $set[1];
644 } else {
645 wfDebugDieBacktrace( "Tag conditions not met. This should never happen and is a bug." );
646 }
647 }
648
649 /**
650 * Normalize whitespace and character references in an XML source-
651 * encoded text for an attribute value.
652 *
653 * See http://www.w3.org/TR/REC-xml/#AVNormalize for background,
654 * but note that we're not returning the value, but are returning
655 * XML source fragments that will be slapped into output.
656 *
657 * @param string $text
658 * @return string
659 * @access private
660 */
661 function normalizeAttributeValue( $text ) {
662 return str_replace( '"', '&quot;',
663 preg_replace(
664 '/\r\n|[\x20\x0d\x0a\x09]/',
665 ' ',
666 Sanitizer::normalizeCharReferences( $text ) ) );
667 }
668
669 /**
670 * Ensure that any entities and character references are legal
671 * for XML and XHTML specifically. Any stray bits will be
672 * &amp;-escaped to result in a valid text fragment.
673 *
674 * a. any named char refs must be known in XHTML
675 * b. any numeric char refs must be legal chars, not invalid or forbidden
676 * c. use &#x, not &#X
677 * d. fix or reject non-valid attributes
678 *
679 * @param string $text
680 * @return string
681 * @access private
682 */
683 function normalizeCharReferences( $text ) {
684 return preg_replace_callback(
685 MW_CHAR_REFS_REGEX,
686 array( 'Sanitizer', 'normalizeCharReferencesCallback' ),
687 $text );
688 }
689 /**
690 * @param string $matches
691 * @return string
692 */
693 function normalizeCharReferencesCallback( $matches ) {
694 $ret = null;
695 if( $matches[1] != '' ) {
696 $ret = Sanitizer::normalizeEntity( $matches[1] );
697 } elseif( $matches[2] != '' ) {
698 $ret = Sanitizer::decCharReference( $matches[2] );
699 } elseif( $matches[3] != '' ) {
700 $ret = Sanitizer::hexCharReference( $matches[3] );
701 } elseif( $matches[4] != '' ) {
702 $ret = Sanitizer::hexCharReference( $matches[4] );
703 }
704 if( is_null( $ret ) ) {
705 return htmlspecialchars( $matches[0] );
706 } else {
707 return $ret;
708 }
709 }
710
711 /**
712 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
713 * return the named entity reference as is. Otherwise, returns
714 * HTML-escaped text of pseudo-entity source (eg &amp;foo;)
715 *
716 * @param string $name
717 * @return string
718 */
719 function normalizeEntity( $name ) {
720 global $wgHtmlEntities;
721 if( isset( $wgHtmlEntities[$name] ) ) {
722 return "&$name;";
723 } else {
724 return "&amp;$name;";
725 }
726 }
727
728 function decCharReference( $codepoint ) {
729 $point = IntVal( $codepoint );
730 if( Sanitizer::validateCodepoint( $point ) ) {
731 return sprintf( '&#%d;', $point );
732 } else {
733 return null;
734 }
735 }
736
737 function hexCharReference( $codepoint ) {
738 $point = hexdec( $codepoint );
739 if( Sanitizer::validateCodepoint( $point ) ) {
740 return sprintf( '&#x%x;', $point );
741 } else {
742 return null;
743 }
744 }
745
746 /**
747 * Returns true if a given Unicode codepoint is a valid character in XML.
748 * @param int $codepoint
749 * @return bool
750 */
751 function validateCodepoint( $codepoint ) {
752 return ($codepoint == 0x09)
753 || ($codepoint == 0x0a)
754 || ($codepoint == 0x0d)
755 || ($codepoint >= 0x20 && $codepoint <= 0xd7ff)
756 || ($codepoint >= 0xe000 && $codepoint <= 0xfffd)
757 || ($codepoint >= 0x10000 && $codepoint <= 0x10ffff);
758 }
759
760 /**
761 * Decode any character references, numeric or named entities,
762 * in the text and return a UTF-8 string.
763 *
764 * @param string $text
765 * @return string
766 * @access public
767 */
768 function decodeCharReferences( $text ) {
769 return preg_replace_callback(
770 MW_CHAR_REFS_REGEX,
771 array( 'Sanitizer', 'decodeCharReferencesCallback' ),
772 $text );
773 }
774
775 /**
776 * @param string $matches
777 * @return string
778 */
779 function decodeCharReferencesCallback( $matches ) {
780 if( $matches[1] != '' ) {
781 return Sanitizer::decodeEntity( $matches[1] );
782 } elseif( $matches[2] != '' ) {
783 return Sanitizer::decodeChar( intval( $matches[2] ) );
784 } elseif( $matches[3] != '' ) {
785 return Sanitizer::decodeChar( hexdec( $matches[3] ) );
786 } elseif( $matches[4] != '' ) {
787 return Sanitizer::decodeChar( hexdec( $matches[4] ) );
788 }
789 # Last case should be an ampersand by itself
790 return $matches[0];
791 }
792
793 /**
794 * Return UTF-8 string for a codepoint if that is a valid
795 * character reference, otherwise U+FFFD REPLACEMENT CHARACTER.
796 * @param int $codepoint
797 * @return string
798 * @access private
799 */
800 function decodeChar( $codepoint ) {
801 if( Sanitizer::validateCodepoint( $codepoint ) ) {
802 return codepointToUtf8( $codepoint );
803 } else {
804 return UTF8_REPLACEMENT;
805 }
806 }
807
808 /**
809 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
810 * return the UTF-8 encoding of that character. Otherwise, returns
811 * pseudo-entity source (eg &foo;)
812 *
813 * @param string $name
814 * @return string
815 */
816 function decodeEntity( $name ) {
817 global $wgHtmlEntities;
818 if( isset( $wgHtmlEntities[$name] ) ) {
819 return codepointToUtf8( $wgHtmlEntities[$name] );
820 } else {
821 return "&$name;";
822 }
823 }
824
825 /**
826 * Fetch the whitelist of acceptable attributes for a given
827 * element name.
828 *
829 * @param string $element
830 * @return array
831 */
832 function attributeWhitelist( $element ) {
833 static $list;
834 if( !isset( $list ) ) {
835 $list = Sanitizer::setupAttributeWhitelist();
836 }
837 return isset( $list[$element] )
838 ? $list[$element]
839 : array();
840 }
841
842 /**
843 * @return array
844 */
845 function setupAttributeWhitelist() {
846 $common = array( 'id', 'class', 'lang', 'dir', 'title', 'style' );
847 $block = array_merge( $common, array( 'align' ) );
848 $tablealign = array( 'align', 'char', 'charoff', 'valign' );
849 $tablecell = array( 'abbr',
850 'axis',
851 'headers',
852 'scope',
853 'rowspan',
854 'colspan',
855 'nowrap', # deprecated
856 'width', # deprecated
857 'height', # deprecated
858 'bgcolor' # deprecated
859 );
860
861 # Numbers refer to sections in HTML 4.01 standard describing the element.
862 # See: http://www.w3.org/TR/html4/
863 $whitelist = array (
864 # 7.5.4
865 'div' => $block,
866 'center' => $common, # deprecated
867 'span' => $block, # ??
868
869 # 7.5.5
870 'h1' => $block,
871 'h2' => $block,
872 'h3' => $block,
873 'h4' => $block,
874 'h5' => $block,
875 'h6' => $block,
876
877 # 7.5.6
878 # address
879
880 # 8.2.4
881 # bdo
882
883 # 9.2.1
884 'em' => $common,
885 'strong' => $common,
886 'cite' => $common,
887 # dfn
888 'code' => $common,
889 # samp
890 # kbd
891 'var' => $common,
892 # abbr
893 # acronym
894
895 # 9.2.2
896 'blockquote' => array_merge( $common, array( 'cite' ) ),
897 # q
898
899 # 9.2.3
900 'sub' => $common,
901 'sup' => $common,
902
903 # 9.3.1
904 'p' => $block,
905
906 # 9.3.2
907 'br' => array( 'id', 'class', 'title', 'style', 'clear' ),
908
909 # 9.3.4
910 'pre' => array_merge( $common, array( 'width' ) ),
911
912 # 9.4
913 'ins' => array_merge( $common, array( 'cite', 'datetime' ) ),
914 'del' => array_merge( $common, array( 'cite', 'datetime' ) ),
915
916 # 10.2
917 'ul' => array_merge( $common, array( 'type' ) ),
918 'ol' => array_merge( $common, array( 'type', 'start' ) ),
919 'li' => array_merge( $common, array( 'type', 'value' ) ),
920
921 # 10.3
922 'dl' => $common,
923 'dd' => $common,
924 'dt' => $common,
925
926 # 11.2.1
927 'table' => array_merge( $common,
928 array( 'summary', 'width', 'border', 'frame',
929 'rules', 'cellspacing', 'cellpadding',
930 'align', 'bgcolor', 'frame', 'rules',
931 'border' ) ),
932
933 # 11.2.2
934 'caption' => array_merge( $common, array( 'align' ) ),
935
936 # 11.2.3
937 'thead' => array_merge( $common, $tablealign ),
938 'tfoot' => array_merge( $common, $tablealign ),
939 'tbody' => array_merge( $common, $tablealign ),
940
941 # 11.2.4
942 'colgroup' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
943 'col' => array_merge( $common, array( 'span', 'width' ), $tablealign ),
944
945 # 11.2.5
946 'tr' => array_merge( $common, array( 'bgcolor' ), $tablealign ),
947
948 # 11.2.6
949 'td' => array_merge( $common, $tablecell, $tablealign ),
950 'th' => array_merge( $common, $tablecell, $tablealign ),
951
952 # 15.2.1
953 'tt' => $common,
954 'b' => $common,
955 'i' => $common,
956 'big' => $common,
957 'small' => $common,
958 'strike' => $common,
959 's' => $common,
960 'u' => $common,
961
962 # 15.2.2
963 'font' => array_merge( $common, array( 'size', 'color', 'face' ) ),
964 # basefont
965
966 # 15.3
967 'hr' => array_merge( $common, array( 'noshade', 'size', 'width' ) ),
968
969 # XHTML Ruby annotation text module, simple ruby only.
970 # http://www.w3c.org/TR/ruby/
971 'ruby' => $common,
972 # rbc
973 # rtc
974 'rb' => $common,
975 'rt' => $common, #array_merge( $common, array( 'rbspan' ) ),
976 'rp' => $common,
977 );
978 return $whitelist;
979 }
980
981 /**
982 * Take a fragment of (potentially invalid) HTML and return
983 * a version with any tags removed, encoded suitably for literal
984 * inclusion in an attribute value.
985 *
986 * @param string $text HTML fragment
987 * @return string
988 */
989 function stripAllTags( $text ) {
990 # Actual <tags>
991 $text = preg_replace( '/<[^>]*>/', '', $text );
992
993 # Normalize &entities and whitespace
994 $text = Sanitizer::normalizeAttributeValue( $text );
995
996 # Will be placed into "double-quoted" attributes,
997 # make sure remaining bits are safe.
998 $text = str_replace(
999 array('<', '>', '"'),
1000 array('&lt;', '&gt;', '&quot;'),
1001 $text );
1002
1003 return $text;
1004 }
1005
1006 }
1007
1008 ?>
MediaWiki Core