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SECURITY: blacklist CSS var()
[lhc/web/wiklou.git] / includes / parser / Sanitizer.php
1 <?php
2 /**
3 * HTML sanitizer for %MediaWiki.
4 *
5 * Copyright © 2002-2005 Brion Vibber <brion@pobox.com> et al
6 * https://www.mediawiki.org/
7 *
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.
12 *
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.
17 *
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
22 *
23 * @file
24 * @ingroup Parser
25 */
26
27 use MediaWiki\MediaWikiServices;
28
29 /**
30 * HTML sanitizer for MediaWiki
31 * @ingroup Parser
32 */
33 class Sanitizer {
34 /**
35 * Regular expression to match various types of character references in
36 * Sanitizer::normalizeCharReferences and Sanitizer::decodeCharReferences
37 */
38 const CHAR_REFS_REGEX =
39 '/&([A-Za-z0-9\x80-\xff]+);
40 |&\#([0-9]+);
41 |&\#[xX]([0-9A-Fa-f]+);
42 |(&)/x';
43
44 /**
45 * Acceptable tag name charset from HTML5 parsing spec
46 * https://www.w3.org/TR/html5/syntax.html#tag-open-state
47 */
48 const ELEMENT_BITS_REGEX = '!^(/?)([A-Za-z][^\t\n\v />\0]*+)([^>]*?)(/?>)([^<]*)$!';
49
50 /**
51 * Blacklist for evil uris like javascript:
52 * WARNING: DO NOT use this in any place that actually requires blacklisting
53 * for security reasons. There are NUMEROUS[1] ways to bypass blacklisting, the
54 * only way to be secure from javascript: uri based xss vectors is to whitelist
55 * things that you know are safe and deny everything else.
56 * [1]: http://ha.ckers.org/xss.html
57 */
58 const EVIL_URI_PATTERN = '!(^|\s|\*/\s*)(javascript|vbscript)([^\w]|$)!i';
59 const XMLNS_ATTRIBUTE_PATTERN = "/^xmlns:[:A-Z_a-z-.0-9]+$/";
60
61 /**
62 * Tells escapeUrlForHtml() to encode the ID using the wiki's primary encoding.
63 *
64 * @since 1.30
65 */
66 const ID_PRIMARY = 0;
67
68 /**
69 * Tells escapeUrlForHtml() to encode the ID using the fallback encoding, or return false
70 * if no fallback is configured.
71 *
72 * @since 1.30
73 */
74 const ID_FALLBACK = 1;
75
76 /**
77 * List of all named character entities defined in HTML 4.01
78 * https://www.w3.org/TR/html4/sgml/entities.html
79 * As well as &apos; which is only defined starting in XHTML1.
80 */
81 private static $htmlEntities = [
82 'Aacute' => 193,
83 'aacute' => 225,
84 'Acirc' => 194,
85 'acirc' => 226,
86 'acute' => 180,
87 'AElig' => 198,
88 'aelig' => 230,
89 'Agrave' => 192,
90 'agrave' => 224,
91 'alefsym' => 8501,
92 'Alpha' => 913,
93 'alpha' => 945,
94 'amp' => 38,
95 'and' => 8743,
96 'ang' => 8736,
97 'apos' => 39, // New in XHTML & HTML 5; avoid in output for compatibility with IE.
98 'Aring' => 197,
99 'aring' => 229,
100 'asymp' => 8776,
101 'Atilde' => 195,
102 'atilde' => 227,
103 'Auml' => 196,
104 'auml' => 228,
105 'bdquo' => 8222,
106 'Beta' => 914,
107 'beta' => 946,
108 'brvbar' => 166,
109 'bull' => 8226,
110 'cap' => 8745,
111 'Ccedil' => 199,
112 'ccedil' => 231,
113 'cedil' => 184,
114 'cent' => 162,
115 'Chi' => 935,
116 'chi' => 967,
117 'circ' => 710,
118 'clubs' => 9827,
119 'cong' => 8773,
120 'copy' => 169,
121 'crarr' => 8629,
122 'cup' => 8746,
123 'curren' => 164,
124 'dagger' => 8224,
125 'Dagger' => 8225,
126 'darr' => 8595,
127 'dArr' => 8659,
128 'deg' => 176,
129 'Delta' => 916,
130 'delta' => 948,
131 'diams' => 9830,
132 'divide' => 247,
133 'Eacute' => 201,
134 'eacute' => 233,
135 'Ecirc' => 202,
136 'ecirc' => 234,
137 'Egrave' => 200,
138 'egrave' => 232,
139 'empty' => 8709,
140 'emsp' => 8195,
141 'ensp' => 8194,
142 'Epsilon' => 917,
143 'epsilon' => 949,
144 'equiv' => 8801,
145 'Eta' => 919,
146 'eta' => 951,
147 'ETH' => 208,
148 'eth' => 240,
149 'Euml' => 203,
150 'euml' => 235,
151 'euro' => 8364,
152 'exist' => 8707,
153 'fnof' => 402,
154 'forall' => 8704,
155 'frac12' => 189,
156 'frac14' => 188,
157 'frac34' => 190,
158 'frasl' => 8260,
159 'Gamma' => 915,
160 'gamma' => 947,
161 'ge' => 8805,
162 'gt' => 62,
163 'harr' => 8596,
164 'hArr' => 8660,
165 'hearts' => 9829,
166 'hellip' => 8230,
167 'Iacute' => 205,
168 'iacute' => 237,
169 'Icirc' => 206,
170 'icirc' => 238,
171 'iexcl' => 161,
172 'Igrave' => 204,
173 'igrave' => 236,
174 'image' => 8465,
175 'infin' => 8734,
176 'int' => 8747,
177 'Iota' => 921,
178 'iota' => 953,
179 'iquest' => 191,
180 'isin' => 8712,
181 'Iuml' => 207,
182 'iuml' => 239,
183 'Kappa' => 922,
184 'kappa' => 954,
185 'Lambda' => 923,
186 'lambda' => 955,
187 'lang' => 9001,
188 'laquo' => 171,
189 'larr' => 8592,
190 'lArr' => 8656,
191 'lceil' => 8968,
192 'ldquo' => 8220,
193 'le' => 8804,
194 'lfloor' => 8970,
195 'lowast' => 8727,
196 'loz' => 9674,
197 'lrm' => 8206,
198 'lsaquo' => 8249,
199 'lsquo' => 8216,
200 'lt' => 60,
201 'macr' => 175,
202 'mdash' => 8212,
203 'micro' => 181,
204 'middot' => 183,
205 'minus' => 8722,
206 'Mu' => 924,
207 'mu' => 956,
208 'nabla' => 8711,
209 'nbsp' => 160,
210 'ndash' => 8211,
211 'ne' => 8800,
212 'ni' => 8715,
213 'not' => 172,
214 'notin' => 8713,
215 'nsub' => 8836,
216 'Ntilde' => 209,
217 'ntilde' => 241,
218 'Nu' => 925,
219 'nu' => 957,
220 'Oacute' => 211,
221 'oacute' => 243,
222 'Ocirc' => 212,
223 'ocirc' => 244,
224 'OElig' => 338,
225 'oelig' => 339,
226 'Ograve' => 210,
227 'ograve' => 242,
228 'oline' => 8254,
229 'Omega' => 937,
230 'omega' => 969,
231 'Omicron' => 927,
232 'omicron' => 959,
233 'oplus' => 8853,
234 'or' => 8744,
235 'ordf' => 170,
236 'ordm' => 186,
237 'Oslash' => 216,
238 'oslash' => 248,
239 'Otilde' => 213,
240 'otilde' => 245,
241 'otimes' => 8855,
242 'Ouml' => 214,
243 'ouml' => 246,
244 'para' => 182,
245 'part' => 8706,
246 'permil' => 8240,
247 'perp' => 8869,
248 'Phi' => 934,
249 'phi' => 966,
250 'Pi' => 928,
251 'pi' => 960,
252 'piv' => 982,
253 'plusmn' => 177,
254 'pound' => 163,
255 'prime' => 8242,
256 'Prime' => 8243,
257 'prod' => 8719,
258 'prop' => 8733,
259 'Psi' => 936,
260 'psi' => 968,
261 'quot' => 34,
262 'radic' => 8730,
263 'rang' => 9002,
264 'raquo' => 187,
265 'rarr' => 8594,
266 'rArr' => 8658,
267 'rceil' => 8969,
268 'rdquo' => 8221,
269 'real' => 8476,
270 'reg' => 174,
271 'rfloor' => 8971,
272 'Rho' => 929,
273 'rho' => 961,
274 'rlm' => 8207,
275 'rsaquo' => 8250,
276 'rsquo' => 8217,
277 'sbquo' => 8218,
278 'Scaron' => 352,
279 'scaron' => 353,
280 'sdot' => 8901,
281 'sect' => 167,
282 'shy' => 173,
283 'Sigma' => 931,
284 'sigma' => 963,
285 'sigmaf' => 962,
286 'sim' => 8764,
287 'spades' => 9824,
288 'sub' => 8834,
289 'sube' => 8838,
290 'sum' => 8721,
291 'sup' => 8835,
292 'sup1' => 185,
293 'sup2' => 178,
294 'sup3' => 179,
295 'supe' => 8839,
296 'szlig' => 223,
297 'Tau' => 932,
298 'tau' => 964,
299 'there4' => 8756,
300 'Theta' => 920,
301 'theta' => 952,
302 'thetasym' => 977,
303 'thinsp' => 8201,
304 'THORN' => 222,
305 'thorn' => 254,
306 'tilde' => 732,
307 'times' => 215,
308 'trade' => 8482,
309 'Uacute' => 218,
310 'uacute' => 250,
311 'uarr' => 8593,
312 'uArr' => 8657,
313 'Ucirc' => 219,
314 'ucirc' => 251,
315 'Ugrave' => 217,
316 'ugrave' => 249,
317 'uml' => 168,
318 'upsih' => 978,
319 'Upsilon' => 933,
320 'upsilon' => 965,
321 'Uuml' => 220,
322 'uuml' => 252,
323 'weierp' => 8472,
324 'Xi' => 926,
325 'xi' => 958,
326 'Yacute' => 221,
327 'yacute' => 253,
328 'yen' => 165,
329 'Yuml' => 376,
330 'yuml' => 255,
331 'Zeta' => 918,
332 'zeta' => 950,
333 'zwj' => 8205,
334 'zwnj' => 8204
335 ];
336
337 /**
338 * Character entity aliases accepted by MediaWiki
339 */
340 private static $htmlEntityAliases = [
341 'רלמ' => 'rlm',
342 'رلم' => 'rlm',
343 ];
344
345 /**
346 * Lazy-initialised attributes regex, see getAttribsRegex()
347 */
348 private static $attribsRegex;
349
350 /**
351 * Regular expression to match HTML/XML attribute pairs within a tag.
352 * Based on https://www.w3.org/TR/html5/syntax.html#before-attribute-name-state
353 * Used in Sanitizer::decodeTagAttributes
354 * @return string
355 */
356 static function getAttribsRegex() {
357 if ( self::$attribsRegex === null ) {
358 $spaceChars = '\x09\x0a\x0c\x0d\x20';
359 $space = "[{$spaceChars}]";
360 $attrib = "[^{$spaceChars}\/>=]";
361 $attribFirst = "(?:{$attrib}|=)";
362 self::$attribsRegex =
363 "/({$attribFirst}{$attrib}*)
364 ($space*=$space*
365 (?:
366 # The attribute value: quoted or alone
367 \"([^\"]*)(?:\"|\$)
368 | '([^']*)(?:'|\$)
369 | (((?!$space|>).)*)
370 )
371 )?/sxu";
372 }
373 return self::$attribsRegex;
374 }
375
376 /**
377 * Lazy-initialised attribute name regex, see getAttribNameRegex()
378 */
379 private static $attribNameRegex;
380
381 /**
382 * Used in Sanitizer::decodeTagAttributes to filter attributes.
383 * @return string
384 */
385 static function getAttribNameRegex() {
386 if ( self::$attribNameRegex === null ) {
387 $attribFirst = "[:_\p{L}\p{N}]";
388 $attrib = "[:_\.\-\p{L}\p{N}]";
389 self::$attribNameRegex = "/^({$attribFirst}{$attrib}*)$/sxu";
390 }
391 return self::$attribNameRegex;
392 }
393
394 /**
395 * Return the various lists of recognized tags
396 * @param array $extratags For any extra tags to include
397 * @param array $removetags For any tags (default or extra) to exclude
398 * @return array
399 */
400 public static function getRecognizedTagData( $extratags = [], $removetags = [] ) {
401 global $wgAllowImageTag;
402
403 static $htmlpairsStatic, $htmlsingle, $htmlsingleonly, $htmlnest, $tabletags,
404 $htmllist, $listtags, $htmlsingleallowed, $htmlelementsStatic, $staticInitialised;
405
406 // Base our staticInitialised variable off of the global config state so that if the globals
407 // are changed (like in the screwed up test system) we will re-initialise the settings.
408 $globalContext = $wgAllowImageTag;
409 if ( !$staticInitialised || $staticInitialised != $globalContext ) {
410 $htmlpairsStatic = [ # Tags that must be closed
411 'b', 'bdi', 'del', 'i', 'ins', 'u', 'font', 'big', 'small', 'sub', 'sup', 'h1',
412 'h2', 'h3', 'h4', 'h5', 'h6', 'cite', 'code', 'em', 's',
413 'strike', 'strong', 'tt', 'var', 'div', 'center',
414 'blockquote', 'ol', 'ul', 'dl', 'table', 'caption', 'pre',
415 'ruby', 'rb', 'rp', 'rt', 'rtc', 'p', 'span', 'abbr', 'dfn',
416 'kbd', 'samp', 'data', 'time', 'mark'
417 ];
418 $htmlsingle = [
419 'br', 'wbr', 'hr', 'li', 'dt', 'dd', 'meta', 'link'
420 ];
421
422 # Elements that cannot have close tags. This is (not coincidentally)
423 # also the list of tags for which the HTML 5 parsing algorithm
424 # requires you to "acknowledge the token's self-closing flag", i.e.
425 # a self-closing tag like <br/> is not an HTML 5 parse error only
426 # for this list.
427 $htmlsingleonly = [
428 'br', 'wbr', 'hr', 'meta', 'link'
429 ];
430
431 $htmlnest = [ # Tags that can be nested--??
432 'table', 'tr', 'td', 'th', 'div', 'blockquote', 'ol', 'ul',
433 'li', 'dl', 'dt', 'dd', 'font', 'big', 'small', 'sub', 'sup', 'span',
434 'var', 'kbd', 'samp', 'em', 'strong', 'q', 'ruby', 'bdo'
435 ];
436 $tabletags = [ # Can only appear inside table, we will close them
437 'td', 'th', 'tr',
438 ];
439 $htmllist = [ # Tags used by list
440 'ul', 'ol',
441 ];
442 $listtags = [ # Tags that can appear in a list
443 'li',
444 ];
445
446 if ( $wgAllowImageTag ) {
447 $htmlsingle[] = 'img';
448 $htmlsingleonly[] = 'img';
449 }
450
451 $htmlsingleallowed = array_unique( array_merge( $htmlsingle, $tabletags ) );
452 $htmlelementsStatic = array_unique( array_merge( $htmlsingle, $htmlpairsStatic, $htmlnest ) );
453
454 # Convert them all to hashtables for faster lookup
455 $vars = [ 'htmlpairsStatic', 'htmlsingle', 'htmlsingleonly', 'htmlnest', 'tabletags',
456 'htmllist', 'listtags', 'htmlsingleallowed', 'htmlelementsStatic' ];
457 foreach ( $vars as $var ) {
458 $$var = array_flip( $$var );
459 }
460 $staticInitialised = $globalContext;
461 }
462
463 # Populate $htmlpairs and $htmlelements with the $extratags and $removetags arrays
464 $extratags = array_flip( $extratags );
465 $removetags = array_flip( $removetags );
466 $htmlpairs = array_merge( $extratags, $htmlpairsStatic );
467 $htmlelements = array_diff_key( array_merge( $extratags, $htmlelementsStatic ), $removetags );
468
469 return [
470 'htmlpairs' => $htmlpairs,
471 'htmlsingle' => $htmlsingle,
472 'htmlsingleonly' => $htmlsingleonly,
473 'htmlnest' => $htmlnest,
474 'tabletags' => $tabletags,
475 'htmllist' => $htmllist,
476 'listtags' => $listtags,
477 'htmlsingleallowed' => $htmlsingleallowed,
478 'htmlelements' => $htmlelements,
479 ];
480 }
481
482 /**
483 * Cleans up HTML, removes dangerous tags and attributes, and
484 * removes HTML comments
485 * @param string $text
486 * @param callable|null $processCallback Callback to do any variable or parameter
487 * replacements in HTML attribute values
488 * @param array|bool $args Arguments for the processing callback
489 * @param array $extratags For any extra tags to include
490 * @param array $removetags For any tags (default or extra) to exclude
491 * @param callable|null $warnCallback (Deprecated) Callback allowing the
492 * addition of a tracking category when bad input is encountered.
493 * DO NOT ADD NEW PARAMETERS AFTER $warnCallback, since it will be
494 * removed shortly.
495 * @return string
496 */
497 public static function removeHTMLtags( $text, $processCallback = null,
498 $args = [], $extratags = [], $removetags = [], $warnCallback = null
499 ) {
500 $tagData = self::getRecognizedTagData( $extratags, $removetags );
501 $htmlpairs = $tagData['htmlpairs'];
502 $htmlsingle = $tagData['htmlsingle'];
503 $htmlsingleonly = $tagData['htmlsingleonly'];
504 $htmlnest = $tagData['htmlnest'];
505 $tabletags = $tagData['tabletags'];
506 $htmllist = $tagData['htmllist'];
507 $listtags = $tagData['listtags'];
508 $htmlsingleallowed = $tagData['htmlsingleallowed'];
509 $htmlelements = $tagData['htmlelements'];
510
511 # Remove HTML comments
512 $text = self::removeHTMLcomments( $text );
513 $bits = explode( '<', $text );
514 $text = str_replace( '>', '&gt;', array_shift( $bits ) );
515 if ( !MWTidy::isEnabled() ) {
516 wfDeprecated( 'disabling tidy', '1.33' );
517 $tagstack = $tablestack = [];
518 foreach ( $bits as $x ) {
519 $regs = [];
520 # $slash: Does the current element start with a '/'?
521 # $t: Current element name
522 # $params: String between element name and >
523 # $brace: Ending '>' or '/>'
524 # $rest: Everything until the next element of $bits
525 if ( preg_match( self::ELEMENT_BITS_REGEX, $x, $regs ) ) {
526 list( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
527 } else {
528 $slash = $t = $params = $brace = $rest = null;
529 }
530
531 $badtag = false;
532 $t = strtolower( $t );
533 if ( isset( $htmlelements[$t] ) ) {
534 # Check our stack
535 if ( $slash && isset( $htmlsingleonly[$t] ) ) {
536 $badtag = true;
537 } elseif ( $slash ) {
538 # Closing a tag... is it the one we just opened?
539 Wikimedia\suppressWarnings();
540 $ot = array_pop( $tagstack );
541 Wikimedia\restoreWarnings();
542
543 if ( $ot != $t ) {
544 if ( isset( $htmlsingleallowed[$ot] ) ) {
545 # Pop all elements with an optional close tag
546 # and see if we find a match below them
547 $optstack = [];
548 array_push( $optstack, $ot );
549 Wikimedia\suppressWarnings();
550 $ot = array_pop( $tagstack );
551 Wikimedia\restoreWarnings();
552 while ( $ot != $t && isset( $htmlsingleallowed[$ot] ) ) {
553 array_push( $optstack, $ot );
554 Wikimedia\suppressWarnings();
555 $ot = array_pop( $tagstack );
556 Wikimedia\restoreWarnings();
557 }
558 if ( $t != $ot ) {
559 # No match. Push the optional elements back again
560 $badtag = true;
561 Wikimedia\suppressWarnings();
562 $ot = array_pop( $optstack );
563 Wikimedia\restoreWarnings();
564 while ( $ot ) {
565 array_push( $tagstack, $ot );
566 Wikimedia\suppressWarnings();
567 $ot = array_pop( $optstack );
568 Wikimedia\restoreWarnings();
569 }
570 }
571 } else {
572 Wikimedia\suppressWarnings();
573 array_push( $tagstack, $ot );
574 Wikimedia\restoreWarnings();
575
576 # <li> can be nested in <ul> or <ol>, skip those cases:
577 if ( !isset( $htmllist[$ot] ) || !isset( $listtags[$t] ) ) {
578 $badtag = true;
579 }
580 }
581 } elseif ( $t == 'table' ) {
582 $tagstack = array_pop( $tablestack );
583 }
584 $newparams = '';
585 } else {
586 # Keep track for later
587 if ( isset( $tabletags[$t] ) && !in_array( 'table', $tagstack ) ) {
588 $badtag = true;
589 } elseif ( in_array( $t, $tagstack ) && !isset( $htmlnest[$t] ) ) {
590 $badtag = true;
591 #  Is it a self closed htmlpair ? (T7487)
592 } elseif ( $brace == '/>' && isset( $htmlpairs[$t] ) ) {
593 // Eventually we'll just remove the self-closing
594 // slash, in order to be consistent with HTML5
595 // semantics.
596 // $brace = '>';
597 // For now, let's just warn authors to clean up.
598 if ( is_callable( $warnCallback ) ) {
599 call_user_func_array( $warnCallback, [ 'deprecated-self-close-category' ] );
600 }
601 $badtag = true;
602 } elseif ( isset( $htmlsingleonly[$t] ) ) {
603 # Hack to force empty tag for unclosable elements
604 $brace = '/>';
605 } elseif ( isset( $htmlsingle[$t] ) ) {
606 # Hack to not close $htmlsingle tags
607 $brace = null;
608 # Still need to push this optionally-closed tag to
609 # the tag stack so that we can match end tags
610 # instead of marking them as bad.
611 array_push( $tagstack, $t );
612 } elseif ( isset( $tabletags[$t] ) && in_array( $t, $tagstack ) ) {
613 // New table tag but forgot to close the previous one
614 $text .= "</$t>";
615 } else {
616 if ( $t == 'table' ) {
617 array_push( $tablestack, $tagstack );
618 $tagstack = [];
619 }
620 array_push( $tagstack, $t );
621 }
622
623 # Replace any variables or template parameters with
624 # plaintext results.
625 if ( is_callable( $processCallback ) ) {
626 call_user_func_array( $processCallback, [ &$params, $args ] );
627 }
628
629 if ( !self::validateTag( $params, $t ) ) {
630 $badtag = true;
631 }
632
633 # Strip non-approved attributes from the tag
634 $newparams = self::fixTagAttributes( $params, $t );
635 }
636 if ( !$badtag ) {
637 $rest = str_replace( '>', '&gt;', $rest );
638 $close = ( $brace == '/>' && !$slash ) ? ' /' : '';
639 $text .= "<$slash$t$newparams$close>$rest";
640 continue;
641 }
642 }
643 $text .= '&lt;' . str_replace( '>', '&gt;', $x );
644 }
645 # Close off any remaining tags
646 while ( is_array( $tagstack ) && ( $t = array_pop( $tagstack ) ) ) {
647 $text .= "</$t>\n";
648 if ( $t == 'table' ) {
649 $tagstack = array_pop( $tablestack );
650 }
651 }
652 } else {
653 # this might be possible using tidy itself
654 foreach ( $bits as $x ) {
655 if ( preg_match( self::ELEMENT_BITS_REGEX, $x, $regs ) ) {
656 list( /* $qbar */, $slash, $t, $params, $brace, $rest ) = $regs;
657
658 $badtag = false;
659 $t = strtolower( $t );
660 if ( isset( $htmlelements[$t] ) ) {
661 if ( is_callable( $processCallback ) ) {
662 call_user_func_array( $processCallback, [ &$params, $args ] );
663 }
664
665 if ( $brace == '/>' && !( isset( $htmlsingle[$t] ) || isset( $htmlsingleonly[$t] ) ) ) {
666 // Eventually we'll just remove the self-closing
667 // slash, in order to be consistent with HTML5
668 // semantics.
669 // $brace = '>';
670 // For now, let's just warn authors to clean up.
671 if ( is_callable( $warnCallback ) ) {
672 call_user_func_array( $warnCallback, [ 'deprecated-self-close-category' ] );
673 }
674 }
675 if ( !self::validateTag( $params, $t ) ) {
676 $badtag = true;
677 }
678
679 $newparams = self::fixTagAttributes( $params, $t );
680 if ( !$badtag ) {
681 if ( $brace === '/>' && !isset( $htmlsingleonly[$t] ) ) {
682 # Interpret self-closing tags as empty tags even when
683 # HTML 5 would interpret them as start tags. Such input
684 # is commonly seen on Wikimedia wikis with this intention.
685 $brace = "></$t>";
686 }
687
688 $rest = str_replace( '>', '&gt;', $rest );
689 $text .= "<$slash$t$newparams$brace$rest";
690 continue;
691 }
692 }
693 }
694 $text .= '&lt;' . str_replace( '>', '&gt;', $x );
695 }
696 }
697 return $text;
698 }
699
700 /**
701 * Remove '<!--', '-->', and everything between.
702 * To avoid leaving blank lines, when a comment is both preceded
703 * and followed by a newline (ignoring spaces), trim leading and
704 * trailing spaces and one of the newlines.
705 *
706 * @param string $text
707 * @return string
708 */
709 public static function removeHTMLcomments( $text ) {
710 while ( ( $start = strpos( $text, '<!--' ) ) !== false ) {
711 $end = strpos( $text, '-->', $start + 4 );
712 if ( $end === false ) {
713 # Unterminated comment; bail out
714 break;
715 }
716
717 $end += 3;
718
719 # Trim space and newline if the comment is both
720 # preceded and followed by a newline
721 $spaceStart = max( $start - 1, 0 );
722 $spaceLen = $end - $spaceStart;
723 while ( substr( $text, $spaceStart, 1 ) === ' ' && $spaceStart > 0 ) {
724 $spaceStart--;
725 $spaceLen++;
726 }
727 while ( substr( $text, $spaceStart + $spaceLen, 1 ) === ' ' ) {
728 $spaceLen++;
729 }
730 if ( substr( $text, $spaceStart, 1 ) === "\n"
731 && substr( $text, $spaceStart + $spaceLen, 1 ) === "\n" ) {
732 # Remove the comment, leading and trailing
733 # spaces, and leave only one newline.
734 $text = substr_replace( $text, "\n", $spaceStart, $spaceLen + 1 );
735 } else {
736 # Remove just the comment.
737 $text = substr_replace( $text, '', $start, $end - $start );
738 }
739 }
740 return $text;
741 }
742
743 /**
744 * Takes attribute names and values for a tag and the tag name and
745 * validates that the tag is allowed to be present.
746 * This DOES NOT validate the attributes, nor does it validate the
747 * tags themselves. This method only handles the special circumstances
748 * where we may want to allow a tag within content but ONLY when it has
749 * specific attributes set.
750 *
751 * @param string $params
752 * @param string $element
753 * @return bool
754 */
755 static function validateTag( $params, $element ) {
756 $params = self::decodeTagAttributes( $params );
757
758 if ( $element == 'meta' || $element == 'link' ) {
759 if ( !isset( $params['itemprop'] ) ) {
760 // <meta> and <link> must have an itemprop="" otherwise they are not valid or safe in content
761 return false;
762 }
763 if ( $element == 'meta' && !isset( $params['content'] ) ) {
764 // <meta> must have a content="" for the itemprop
765 return false;
766 }
767 if ( $element == 'link' && !isset( $params['href'] ) ) {
768 // <link> must have an associated href=""
769 return false;
770 }
771 }
772
773 return true;
774 }
775
776 /**
777 * Take an array of attribute names and values and normalize or discard
778 * illegal values for the given element type.
779 *
780 * - Discards attributes not on a whitelist for the given element
781 * - Unsafe style attributes are discarded
782 * - Invalid id attributes are re-encoded
783 *
784 * @param array $attribs
785 * @param string $element
786 * @return array
787 *
788 * @todo Check for legal values where the DTD limits things.
789 * @todo Check for unique id attribute :P
790 */
791 static function validateTagAttributes( $attribs, $element ) {
792 return self::validateAttributes( $attribs,
793 self::attributeWhitelist( $element ) );
794 }
795
796 /**
797 * Take an array of attribute names and values and normalize or discard
798 * illegal values for the given whitelist.
799 *
800 * - Discards attributes not on the given whitelist
801 * - Unsafe style attributes are discarded
802 * - Invalid id attributes are re-encoded
803 *
804 * @param array $attribs
805 * @param array $whitelist List of allowed attribute names
806 * @return array
807 *
808 * @todo Check for legal values where the DTD limits things.
809 * @todo Check for unique id attribute :P
810 */
811 static function validateAttributes( $attribs, $whitelist ) {
812 $whitelist = array_flip( $whitelist );
813 $hrefExp = '/^(' . wfUrlProtocols() . ')[^\s]+$/';
814
815 $out = [];
816 foreach ( $attribs as $attribute => $value ) {
817 # Allow XML namespace declaration to allow RDFa
818 if ( preg_match( self::XMLNS_ATTRIBUTE_PATTERN, $attribute ) ) {
819 if ( !preg_match( self::EVIL_URI_PATTERN, $value ) ) {
820 $out[$attribute] = $value;
821 }
822
823 continue;
824 }
825
826 # Allow any attribute beginning with "data-"
827 # However:
828 # * Disallow data attributes used by MediaWiki code
829 # * Ensure that the attribute is not namespaced by banning
830 # colons.
831 if ( !preg_match( '/^data-[^:]*$/i', $attribute )
832 && !isset( $whitelist[$attribute] )
833 || self::isReservedDataAttribute( $attribute )
834 ) {
835 continue;
836 }
837
838 # Strip javascript "expression" from stylesheets.
839 # https://msdn.microsoft.com/en-us/library/ms537634.aspx
840 if ( $attribute == 'style' ) {
841 $value = self::checkCss( $value );
842 }
843
844 # Escape HTML id attributes
845 if ( $attribute === 'id' ) {
846 $value = self::escapeIdForAttribute( $value, self::ID_PRIMARY );
847 }
848
849 # Escape HTML id reference lists
850 if ( $attribute === 'aria-describedby'
851 || $attribute === 'aria-flowto'
852 || $attribute === 'aria-labelledby'
853 || $attribute === 'aria-owns'
854 ) {
855 $value = self::escapeIdReferenceList( $value );
856 }
857
858 // RDFa and microdata properties allow URLs, URIs and/or CURIs.
859 // Check them for sanity.
860 if ( $attribute === 'rel' || $attribute === 'rev'
861 # RDFa
862 || $attribute === 'about' || $attribute === 'property'
863 || $attribute === 'resource' || $attribute === 'datatype'
864 || $attribute === 'typeof'
865 # HTML5 microdata
866 || $attribute === 'itemid' || $attribute === 'itemprop'
867 || $attribute === 'itemref' || $attribute === 'itemscope'
868 || $attribute === 'itemtype'
869 ) {
870 // Paranoia. Allow "simple" values but suppress javascript
871 if ( preg_match( self::EVIL_URI_PATTERN, $value ) ) {
872 continue;
873 }
874 }
875
876 # NOTE: even though elements using href/src are not allowed directly, supply
877 # validation code that can be used by tag hook handlers, etc
878 if ( $attribute === 'href' || $attribute === 'src' || $attribute === 'poster' ) {
879 if ( !preg_match( $hrefExp, $value ) ) {
880 continue; // drop any href or src attributes not using an allowed protocol.
881 // NOTE: this also drops all relative URLs
882 }
883 }
884
885 // If this attribute was previously set, override it.
886 // Output should only have one attribute of each name.
887 $out[$attribute] = $value;
888 }
889
890 # itemtype, itemid, itemref don't make sense without itemscope
891 if ( !array_key_exists( 'itemscope', $out ) ) {
892 unset( $out['itemtype'] );
893 unset( $out['itemid'] );
894 unset( $out['itemref'] );
895 }
896 # TODO: Strip itemprop if we aren't descendants of an itemscope or pointed to by an itemref.
897
898 return $out;
899 }
900
901 /**
902 * Given an attribute name, checks whether it is a reserved data attribute
903 * (such as data-mw-foo) which is unavailable to user-generated HTML so MediaWiki
904 * core and extension code can safely use it to communicate with frontend code.
905 * @param string $attr Attribute name.
906 * @return bool
907 */
908 public static function isReservedDataAttribute( $attr ) {
909 // data-ooui is reserved for ooui.
910 // data-mw and data-parsoid are reserved for parsoid.
911 // data-mw-<name here> is reserved for extensions (or core) if
912 // they need to communicate some data to the client and want to be
913 // sure that it isn't coming from an untrusted user.
914 // We ignore the possibility of namespaces since user-generated HTML
915 // can't use them anymore.
916 return (bool)preg_match( '/^data-(ooui|mw|parsoid)/i', $attr );
917 }
918
919 /**
920 * Merge two sets of HTML attributes. Conflicting items in the second set
921 * will override those in the first, except for 'class' attributes which
922 * will be combined (if they're both strings).
923 *
924 * @todo implement merging for other attributes such as style
925 * @param array $a
926 * @param array $b
927 * @return array
928 */
929 static function mergeAttributes( $a, $b ) {
930 $out = array_merge( $a, $b );
931 if ( isset( $a['class'] ) && isset( $b['class'] )
932 && is_string( $a['class'] ) && is_string( $b['class'] )
933 && $a['class'] !== $b['class']
934 ) {
935 $classes = preg_split( '/\s+/', "{$a['class']} {$b['class']}",
936 -1, PREG_SPLIT_NO_EMPTY );
937 $out['class'] = implode( ' ', array_unique( $classes ) );
938 }
939 return $out;
940 }
941
942 /**
943 * Normalize CSS into a format we can easily search for hostile input
944 * - decode character references
945 * - decode escape sequences
946 * - convert characters that IE6 interprets into ascii
947 * - remove comments, unless the entire value is one single comment
948 * @param string $value the css string
949 * @return string normalized css
950 */
951 public static function normalizeCss( $value ) {
952 // Decode character references like &#123;
953 $value = self::decodeCharReferences( $value );
954
955 // Decode escape sequences and line continuation
956 // See the grammar in the CSS 2 spec, appendix D.
957 // This has to be done AFTER decoding character references.
958 // This means it isn't possible for this function to return
959 // unsanitized escape sequences. It is possible to manufacture
960 // input that contains character references that decode to
961 // escape sequences that decode to character references, but
962 // it's OK for the return value to contain character references
963 // because the caller is supposed to escape those anyway.
964 static $decodeRegex;
965 if ( !$decodeRegex ) {
966 $space = '[\\x20\\t\\r\\n\\f]';
967 $nl = '(?:\\n|\\r\\n|\\r|\\f)';
968 $backslash = '\\\\';
969 $decodeRegex = "/ $backslash
970 (?:
971 ($nl) | # 1. Line continuation
972 ([0-9A-Fa-f]{1,6})$space? | # 2. character number
973 (.) | # 3. backslash cancelling special meaning
974 () | # 4. backslash at end of string
975 )/xu";
976 }
977 $value = preg_replace_callback( $decodeRegex,
978 [ __CLASS__, 'cssDecodeCallback' ], $value );
979
980 // Normalize Halfwidth and Fullwidth Unicode block that IE6 might treat as ascii
981 $value = preg_replace_callback(
982 '/[！-［］-ｚ]/u', // U+FF01 to U+FF5A, excluding U+FF3C (T60088)
983 function ( $matches ) {
984 $cp = UtfNormal\Utils::utf8ToCodepoint( $matches[0] );
985 if ( $cp === false ) {
986 return '';
987 }
988 return chr( $cp - 65248 ); // ASCII range \x21-\x7A
989 },
990 $value
991 );
992
993 // Convert more characters IE6 might treat as ascii
994 // U+0280, U+0274, U+207F, U+029F, U+026A, U+207D, U+208D
995 $value = str_replace(
996 [ 'ʀ', 'ɴ', 'ⁿ', 'ʟ', 'ɪ', '⁽', '₍' ],
997 [ 'r', 'n', 'n', 'l', 'i', '(', '(' ],
998 $value
999 );
1000
1001 // Let the value through if it's nothing but a single comment, to
1002 // allow other functions which may reject it to pass some error
1003 // message through.
1004 if ( !preg_match( '! ^ \s* /\* [^*\\/]* \*/ \s* $ !x', $value ) ) {
1005 // Remove any comments; IE gets token splitting wrong
1006 // This must be done AFTER decoding character references and
1007 // escape sequences, because those steps can introduce comments
1008 // This step cannot introduce character references or escape
1009 // sequences, because it replaces comments with spaces rather
1010 // than removing them completely.
1011 $value = StringUtils::delimiterReplace( '/*', '*/', ' ', $value );
1012
1013 // Remove anything after a comment-start token, to guard against
1014 // incorrect client implementations.
1015 $commentPos = strpos( $value, '/*' );
1016 if ( $commentPos !== false ) {
1017 $value = substr( $value, 0, $commentPos );
1018 }
1019 }
1020
1021 // S followed by repeat, iteration, or prolonged sound marks,
1022 // which IE will treat as "ss"
1023 $value = preg_replace(
1024 '/s(?:
1025 \xE3\x80\xB1 | # U+3031
1026 \xE3\x82\x9D | # U+309D
1027 \xE3\x83\xBC | # U+30FC
1028 \xE3\x83\xBD | # U+30FD
1029 \xEF\xB9\xBC | # U+FE7C
1030 \xEF\xB9\xBD | # U+FE7D
1031 \xEF\xBD\xB0 # U+FF70
1032 )/ix',
1033 'ss',
1034 $value
1035 );
1036
1037 return $value;
1038 }
1039
1040 /**
1041 * Pick apart some CSS and check it for forbidden or unsafe structures.
1042 * Returns a sanitized string. This sanitized string will have
1043 * character references and escape sequences decoded and comments
1044 * stripped (unless it is itself one valid comment, in which case the value
1045 * will be passed through). If the input is just too evil, only a comment
1046 * complaining about evilness will be returned.
1047 *
1048 * Currently URL references, 'expression', 'tps' are forbidden.
1049 *
1050 * NOTE: Despite the fact that character references are decoded, the
1051 * returned string may contain character references given certain
1052 * clever input strings. These character references must
1053 * be escaped before the return value is embedded in HTML.
1054 *
1055 * @param string $value
1056 * @return string
1057 */
1058 static function checkCss( $value ) {
1059 $value = self::normalizeCss( $value );
1060
1061 // Reject problematic keywords and control characters
1062 if ( preg_match( '/[\000-\010\013\016-\037\177]/', $value ) ||
1063 strpos( $value, UtfNormal\Constants::UTF8_REPLACEMENT ) !== false ) {
1064 return '/* invalid control char */';
1065 } elseif ( preg_match(
1066 '! expression
1067 | filter\s*:
1068 | accelerator\s*:
1069 | -o-link\s*:
1070 | -o-link-source\s*:
1071 | -o-replace\s*:
1072 | url\s*\(
1073 | image\s*\(
1074 | image-set\s*\(
1075 | attr\s*\([^)]+[\s,]+url
1076 | var\s*\(
1077 !ix', $value ) ) {
1078 return '/* insecure input */';
1079 }
1080 return $value;
1081 }
1082
1083 /**
1084 * @param array $matches
1085 * @return string
1086 */
1087 static function cssDecodeCallback( $matches ) {
1088 if ( $matches[1] !== '' ) {
1089 // Line continuation
1090 return '';
1091 } elseif ( $matches[2] !== '' ) {
1092 $char = UtfNormal\Utils::codepointToUtf8( hexdec( $matches[2] ) );
1093 } elseif ( $matches[3] !== '' ) {
1094 $char = $matches[3];
1095 } else {
1096 $char = '\\';
1097 }
1098 if ( $char == "\n" || $char == '"' || $char == "'" || $char == '\\' ) {
1099 // These characters need to be escaped in strings
1100 // Clean up the escape sequence to avoid parsing errors by clients
1101 return '\\' . dechex( ord( $char ) ) . ' ';
1102 } else {
1103 // Decode unnecessary escape
1104 return $char;
1105 }
1106 }
1107
1108 /**
1109 * Take a tag soup fragment listing an HTML element's attributes
1110 * and normalize it to well-formed XML, discarding unwanted attributes.
1111 * Output is safe for further wikitext processing, with escaping of
1112 * values that could trigger problems.
1113 *
1114 * - Normalizes attribute names to lowercase
1115 * - Discards attributes not on a whitelist for the given element
1116 * - Turns broken or invalid entities into plaintext
1117 * - Double-quotes all attribute values
1118 * - Attributes without values are given the name as attribute
1119 * - Double attributes are discarded
1120 * - Unsafe style attributes are discarded
1121 * - Prepends space if there are attributes.
1122 * - (Optionally) Sorts attributes by name.
1123 *
1124 * @param string $text
1125 * @param string $element
1126 * @param bool $sorted Whether to sort the attributes (default: false)
1127 * @return string
1128 */
1129 static function fixTagAttributes( $text, $element, $sorted = false ) {
1130 if ( trim( $text ) == '' ) {
1131 return '';
1132 }
1133
1134 $decoded = self::decodeTagAttributes( $text );
1135 $stripped = self::validateTagAttributes( $decoded, $element );
1136
1137 if ( $sorted ) {
1138 ksort( $stripped );
1139 }
1140
1141 return self::safeEncodeTagAttributes( $stripped );
1142 }
1143
1144 /**
1145 * Encode an attribute value for HTML output.
1146 * @param string $text
1147 * @return string HTML-encoded text fragment
1148 */
1149 static function encodeAttribute( $text ) {
1150 $encValue = htmlspecialchars( $text, ENT_QUOTES );
1151
1152 // Whitespace is normalized during attribute decoding,
1153 // so if we've been passed non-spaces we must encode them
1154 // ahead of time or they won't be preserved.
1155 $encValue = strtr( $encValue, [
1156 "\n" => '&#10;',
1157 "\r" => '&#13;',
1158 "\t" => '&#9;',
1159 ] );
1160
1161 return $encValue;
1162 }
1163
1164 /**
1165 * Armor French spaces with a replacement character
1166 *
1167 * @since 1.32
1168 * @param string $text Text to armor
1169 * @param string $space Space character for the French spaces, defaults to '&#160;'
1170 * @return string Armored text
1171 */
1172 public static function armorFrenchSpaces( $text, $space = '&#160;' ) {
1173 // Replace $ with \$ and \ with \\
1174 $space = preg_replace( '#(?<!\\\\)(\\$|\\\\)#', '\\\\$1', $space );
1175 $fixtags = [
1176 # French spaces, last one Guillemet-left
1177 # only if there is something before the space
1178 # and a non-word character after the punctuation.
1179 '/(\S) (?=[?:;!%»›](?!\w))/u' => "\\1$space",
1180 # French spaces, Guillemet-right
1181 '/([«‹]) /u' => "\\1$space",
1182 ];
1183 return preg_replace( array_keys( $fixtags ), array_values( $fixtags ), $text );
1184 }
1185
1186 /**
1187 * Encode an attribute value for HTML tags, with extra armoring
1188 * against further wiki processing.
1189 * @param string $text
1190 * @return string HTML-encoded text fragment
1191 */
1192 static function safeEncodeAttribute( $text ) {
1193 $encValue = self::encodeAttribute( $text );
1194
1195 # Templates and links may be expanded in later parsing,
1196 # creating invalid or dangerous output. Suppress this.
1197 $encValue = strtr( $encValue, [
1198 '<' => '&lt;', // This should never happen,
1199 '>' => '&gt;', // we've received invalid input
1200 '"' => '&quot;', // which should have been escaped.
1201 '{' => '&#123;',
1202 '}' => '&#125;', // prevent unpaired language conversion syntax
1203 '[' => '&#91;',
1204 ']' => '&#93;',
1205 "''" => '&#39;&#39;',
1206 'ISBN' => '&#73;SBN',
1207 'RFC' => '&#82;FC',
1208 'PMID' => '&#80;MID',
1209 '|' => '&#124;',
1210 '__' => '&#95;_',
1211 ] );
1212
1213 # Armor against French spaces detection (T5158)
1214 $encValue = self::armorFrenchSpaces( $encValue, '&#32;' );
1215
1216 # Stupid hack
1217 $encValue = preg_replace_callback(
1218 '/((?i)' . wfUrlProtocols() . ')/',
1219 function ( $matches ) {
1220 return str_replace( ':', '&#58;', $matches[1] );
1221 },
1222 $encValue );
1223 return $encValue;
1224 }
1225
1226 /**
1227 * Given a value, escape it so that it can be used in an id attribute and
1228 * return it. This will use HTML5 validation, allowing anything but ASCII
1229 * whitespace.
1230 *
1231 * To ensure we don't have to bother escaping anything, we also strip ', ".
1232 * TODO: Is this the best tactic?
1233 *
1234 * We also strip # because it upsets IE, and % because it could be
1235 * ambiguous if it's part of something that looks like a percent escape
1236 * (which don't work reliably in fragments cross-browser).
1237 *
1238 * @deprecated since 1.30, use one of this class' escapeIdFor*() functions
1239 *
1240 * @see https://www.w3.org/TR/html401/types.html#type-name Valid characters
1241 * in the id and name attributes
1242 * @see https://www.w3.org/TR/html401/struct/links.html#h-12.2.3 Anchors with
1243 * the id attribute
1244 * @see https://www.w3.org/TR/html5/dom.html#the-id-attribute
1245 * HTML5 definition of id attribute
1246 *
1247 * @param string $id Id to escape
1248 * @param string|array $options String or array of strings (default is array()):
1249 * 'noninitial': This is a non-initial fragment of an id, not a full id,
1250 * so don't pay attention if the first character isn't valid at the
1251 * beginning of an id.
1252 * @return string
1253 */
1254 static function escapeId( $id, $options = [] ) {
1255 $options = (array)$options;
1256
1257 // HTML4-style escaping
1258 static $replace = [
1259 '%3A' => ':',
1260 '%' => '.'
1261 ];
1262
1263 $id = urlencode( strtr( $id, ' ', '_' ) );
1264 $id = strtr( $id, $replace );
1265
1266 if ( !preg_match( '/^[a-zA-Z]/', $id ) && !in_array( 'noninitial', $options ) ) {
1267 // Initial character must be a letter!
1268 $id = "x$id";
1269 }
1270 return $id;
1271 }
1272
1273 /**
1274 * Given a section name or other user-generated or otherwise unsafe string, escapes it to be
1275 * a valid HTML id attribute.
1276 *
1277 * WARNING: unlike escapeId(), the output of this function is not guaranteed to be HTML safe,
1278 * be sure to use proper escaping.
1279 *
1280 * @param string $id String to escape
1281 * @param int $mode One of ID_* constants, specifying whether the primary or fallback encoding
1282 * should be used.
1283 * @return string|bool Escaped ID or false if fallback encoding is requested but it's not
1284 * configured.
1285 *
1286 * @since 1.30
1287 */
1288 public static function escapeIdForAttribute( $id, $mode = self::ID_PRIMARY ) {
1289 global $wgFragmentMode;
1290
1291 if ( !isset( $wgFragmentMode[$mode] ) ) {
1292 if ( $mode === self::ID_PRIMARY ) {
1293 throw new UnexpectedValueException( '$wgFragmentMode is configured with no primary mode' );
1294 }
1295 return false;
1296 }
1297
1298 $internalMode = $wgFragmentMode[$mode];
1299
1300 return self::escapeIdInternal( $id, $internalMode );
1301 }
1302
1303 /**
1304 * Given a section name or other user-generated or otherwise unsafe string, escapes it to be
1305 * a valid URL fragment.
1306 *
1307 * WARNING: unlike escapeId(), the output of this function is not guaranteed to be HTML safe,
1308 * be sure to use proper escaping.
1309 *
1310 * @param string $id String to escape
1311 * @return string Escaped ID
1312 *
1313 * @since 1.30
1314 */
1315 public static function escapeIdForLink( $id ) {
1316 global $wgFragmentMode;
1317
1318 if ( !isset( $wgFragmentMode[self::ID_PRIMARY] ) ) {
1319 throw new UnexpectedValueException( '$wgFragmentMode is configured with no primary mode' );
1320 }
1321
1322 $mode = $wgFragmentMode[self::ID_PRIMARY];
1323
1324 $id = self::escapeIdInternal( $id, $mode );
1325
1326 return $id;
1327 }
1328
1329 /**
1330 * Given a section name or other user-generated or otherwise unsafe string, escapes it to be
1331 * a valid URL fragment for external interwikis.
1332 *
1333 * @param string $id String to escape
1334 * @return string Escaped ID
1335 *
1336 * @since 1.30
1337 */
1338 public static function escapeIdForExternalInterwiki( $id ) {
1339 global $wgExternalInterwikiFragmentMode;
1340
1341 $id = self::escapeIdInternal( $id, $wgExternalInterwikiFragmentMode );
1342
1343 return $id;
1344 }
1345
1346 /**
1347 * Helper for escapeIdFor*() functions. Performs most of the actual escaping.
1348 *
1349 * @param string $id String to escape
1350 * @param string $mode One of modes from $wgFragmentMode
1351 * @return string
1352 */
1353 private static function escapeIdInternal( $id, $mode ) {
1354 switch ( $mode ) {
1355 case 'html5':
1356 $id = str_replace( ' ', '_', $id );
1357 break;
1358 case 'legacy':
1359 // This corresponds to 'noninitial' mode of the old escapeId()
1360 static $replace = [
1361 '%3A' => ':',
1362 '%' => '.'
1363 ];
1364
1365 $id = urlencode( str_replace( ' ', '_', $id ) );
1366 $id = strtr( $id, $replace );
1367 break;
1368 default:
1369 throw new InvalidArgumentException( "Invalid mode '$mode' passed to '" . __METHOD__ );
1370 }
1371
1372 return $id;
1373 }
1374
1375 /**
1376 * Given a string containing a space delimited list of ids, escape each id
1377 * to match ids escaped by the escapeIdForAttribute() function.
1378 *
1379 * @since 1.27
1380 *
1381 * @param string $referenceString Space delimited list of ids
1382 * @return string
1383 */
1384 public static function escapeIdReferenceList( $referenceString ) {
1385 # Explode the space delimited list string into an array of tokens
1386 $references = preg_split( '/\s+/', "{$referenceString}", -1, PREG_SPLIT_NO_EMPTY );
1387
1388 # Escape each token as an id
1389 foreach ( $references as &$ref ) {
1390 $ref = self::escapeIdForAttribute( $ref );
1391 }
1392
1393 # Merge the array back to a space delimited list string
1394 # If the array is empty, the result will be an empty string ('')
1395 $referenceString = implode( ' ', $references );
1396
1397 return $referenceString;
1398 }
1399
1400 /**
1401 * Given a value, escape it so that it can be used as a CSS class and
1402 * return it.
1403 *
1404 * @todo For extra validity, input should be validated UTF-8.
1405 *
1406 * @see https://www.w3.org/TR/CSS21/syndata.html Valid characters/format
1407 *
1408 * @param string $class
1409 * @return string
1410 */
1411 static function escapeClass( $class ) {
1412 // Convert ugly stuff to underscores and kill underscores in ugly places
1413 return rtrim( preg_replace(
1414 [ '/(^[0-9\\-])|[\\x00-\\x20!"#$%&\'()*+,.\\/:;<=>?@[\\]^`{|}~]|\\xC2\\xA0/', '/_+/' ],
1415 '_',
1416 $class ), '_' );
1417 }
1418
1419 /**
1420 * Given HTML input, escape with htmlspecialchars but un-escape entities.
1421 * This allows (generally harmless) entities like &#160; to survive.
1422 *
1423 * @param string $html HTML to escape
1424 * @return string Escaped input
1425 */
1426 static function escapeHtmlAllowEntities( $html ) {
1427 $html = self::decodeCharReferences( $html );
1428 # It seems wise to escape ' as well as ", as a matter of course. Can't
1429 # hurt. Use ENT_SUBSTITUTE so that incorrectly truncated multibyte characters
1430 # don't cause the entire string to disappear.
1431 $html = htmlspecialchars( $html, ENT_QUOTES | ENT_SUBSTITUTE );
1432 return $html;
1433 }
1434
1435 /**
1436 * Return an associative array of attribute names and values from
1437 * a partial tag string. Attribute names are forced to lowercase,
1438 * character references are decoded to UTF-8 text.
1439 *
1440 * @param string $text
1441 * @return array
1442 */
1443 public static function decodeTagAttributes( $text ) {
1444 if ( trim( $text ) == '' ) {
1445 return [];
1446 }
1447
1448 $pairs = [];
1449 if ( !preg_match_all(
1450 self::getAttribsRegex(),
1451 $text,
1452 $pairs,
1453 PREG_SET_ORDER ) ) {
1454 return [];
1455 }
1456
1457 $attribs = [];
1458 foreach ( $pairs as $set ) {
1459 $attribute = strtolower( $set[1] );
1460
1461 // Filter attribute names with unacceptable characters
1462 if ( !preg_match( self::getAttribNameRegex(), $attribute ) ) {
1463 continue;
1464 }
1465
1466 $value = self::getTagAttributeCallback( $set );
1467
1468 // Normalize whitespace
1469 $value = preg_replace( '/[\t\r\n ]+/', ' ', $value );
1470 $value = trim( $value );
1471
1472 // Decode character references
1473 $attribs[$attribute] = self::decodeCharReferences( $value );
1474 }
1475 return $attribs;
1476 }
1477
1478 /**
1479 * Build a partial tag string from an associative array of attribute
1480 * names and values as returned by decodeTagAttributes.
1481 *
1482 * @param array $assoc_array
1483 * @return string
1484 */
1485 public static function safeEncodeTagAttributes( $assoc_array ) {
1486 $attribs = [];
1487 foreach ( $assoc_array as $attribute => $value ) {
1488 $encAttribute = htmlspecialchars( $attribute );
1489 $encValue = self::safeEncodeAttribute( $value );
1490
1491 $attribs[] = "$encAttribute=\"$encValue\"";
1492 }
1493 return count( $attribs ) ? ' ' . implode( ' ', $attribs ) : '';
1494 }
1495
1496 /**
1497 * Pick the appropriate attribute value from a match set from the
1498 * attribs regex matches.
1499 *
1500 * @param array $set
1501 * @throws MWException When tag conditions are not met.
1502 * @return string
1503 */
1504 private static function getTagAttributeCallback( $set ) {
1505 if ( isset( $set[5] ) ) {
1506 # No quotes.
1507 return $set[5];
1508 } elseif ( isset( $set[4] ) ) {
1509 # Single-quoted
1510 return $set[4];
1511 } elseif ( isset( $set[3] ) ) {
1512 # Double-quoted
1513 return $set[3];
1514 } elseif ( !isset( $set[2] ) ) {
1515 # In XHTML, attributes must have a value so return an empty string.
1516 # See "Empty attribute syntax",
1517 # https://www.w3.org/TR/html5/syntax.html#syntax-attribute-name
1518 return "";
1519 } else {
1520 throw new MWException( "Tag conditions not met. This should never happen and is a bug." );
1521 }
1522 }
1523
1524 /**
1525 * @param string $text
1526 * @return string
1527 */
1528 private static function normalizeWhitespace( $text ) {
1529 return trim( preg_replace(
1530 '/(?:\r\n|[\x20\x0d\x0a\x09])+/',
1531 ' ',
1532 $text ) );
1533 }
1534
1535 /**
1536 * Normalizes whitespace in a section name, such as might be returned
1537 * by Parser::stripSectionName(), for use in the id's that are used for
1538 * section links.
1539 *
1540 * @param string $section
1541 * @return string
1542 */
1543 static function normalizeSectionNameWhitespace( $section ) {
1544 return trim( preg_replace( '/[ _]+/', ' ', $section ) );
1545 }
1546
1547 /**
1548 * Ensure that any entities and character references are legal
1549 * for XML and XHTML specifically. Any stray bits will be
1550 * &amp;-escaped to result in a valid text fragment.
1551 *
1552 * a. named char refs can only be &lt; &gt; &amp; &quot;, others are
1553 * numericized (this way we're well-formed even without a DTD)
1554 * b. any numeric char refs must be legal chars, not invalid or forbidden
1555 * c. use lower cased "&#x", not "&#X"
1556 * d. fix or reject non-valid attributes
1557 *
1558 * @param string $text
1559 * @return string
1560 * @private
1561 */
1562 static function normalizeCharReferences( $text ) {
1563 return preg_replace_callback(
1564 self::CHAR_REFS_REGEX,
1565 [ self::class, 'normalizeCharReferencesCallback' ],
1566 $text );
1567 }
1568
1569 /**
1570 * @param string $matches
1571 * @return string
1572 */
1573 static function normalizeCharReferencesCallback( $matches ) {
1574 $ret = null;
1575 if ( $matches[1] != '' ) {
1576 $ret = self::normalizeEntity( $matches[1] );
1577 } elseif ( $matches[2] != '' ) {
1578 $ret = self::decCharReference( $matches[2] );
1579 } elseif ( $matches[3] != '' ) {
1580 $ret = self::hexCharReference( $matches[3] );
1581 }
1582 if ( is_null( $ret ) ) {
1583 return htmlspecialchars( $matches[0] );
1584 } else {
1585 return $ret;
1586 }
1587 }
1588
1589 /**
1590 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1591 * return the equivalent numeric entity reference (except for the core &lt;
1592 * &gt; &amp; &quot;). If the entity is a MediaWiki-specific alias, returns
1593 * the HTML equivalent. Otherwise, returns HTML-escaped text of
1594 * pseudo-entity source (eg &amp;foo;)
1595 *
1596 * @param string $name
1597 * @return string
1598 */
1599 static function normalizeEntity( $name ) {
1600 if ( isset( self::$htmlEntityAliases[$name] ) ) {
1601 return '&' . self::$htmlEntityAliases[$name] . ';';
1602 } elseif ( in_array( $name, [ 'lt', 'gt', 'amp', 'quot' ] ) ) {
1603 return "&$name;";
1604 } elseif ( isset( self::$htmlEntities[$name] ) ) {
1605 return '&#' . self::$htmlEntities[$name] . ';';
1606 } else {
1607 return "&amp;$name;";
1608 }
1609 }
1610
1611 /**
1612 * @param int $codepoint
1613 * @return null|string
1614 */
1615 static function decCharReference( $codepoint ) {
1616 $point = intval( $codepoint );
1617 if ( self::validateCodepoint( $point ) ) {
1618 return sprintf( '&#%d;', $point );
1619 } else {
1620 return null;
1621 }
1622 }
1623
1624 /**
1625 * @param int $codepoint
1626 * @return null|string
1627 */
1628 static function hexCharReference( $codepoint ) {
1629 $point = hexdec( $codepoint );
1630 if ( self::validateCodepoint( $point ) ) {
1631 return sprintf( '&#x%x;', $point );
1632 } else {
1633 return null;
1634 }
1635 }
1636
1637 /**
1638 * Returns true if a given Unicode codepoint is a valid character in
1639 * both HTML5 and XML.
1640 * @param int $codepoint
1641 * @return bool
1642 */
1643 private static function validateCodepoint( $codepoint ) {
1644 # U+000C is valid in HTML5 but not allowed in XML.
1645 # U+000D is valid in XML but not allowed in HTML5.
1646 # U+007F - U+009F are disallowed in HTML5 (control characters).
1647 return $codepoint == 0x09
1648 || $codepoint == 0x0a
1649 || ( $codepoint >= 0x20 && $codepoint <= 0x7e )
1650 || ( $codepoint >= 0xa0 && $codepoint <= 0xd7ff )
1651 || ( $codepoint >= 0xe000 && $codepoint <= 0xfffd )
1652 || ( $codepoint >= 0x10000 && $codepoint <= 0x10ffff );
1653 }
1654
1655 /**
1656 * Decode any character references, numeric or named entities,
1657 * in the text and return a UTF-8 string.
1658 *
1659 * @param string $text
1660 * @return string
1661 */
1662 public static function decodeCharReferences( $text ) {
1663 return preg_replace_callback(
1664 self::CHAR_REFS_REGEX,
1665 [ self::class, 'decodeCharReferencesCallback' ],
1666 $text );
1667 }
1668
1669 /**
1670 * Decode any character references, numeric or named entities,
1671 * in the next and normalize the resulting string. (T16952)
1672 *
1673 * This is useful for page titles, not for text to be displayed,
1674 * MediaWiki allows HTML entities to escape normalization as a feature.
1675 *
1676 * @param string $text Already normalized, containing entities
1677 * @return string Still normalized, without entities
1678 */
1679 public static function decodeCharReferencesAndNormalize( $text ) {
1680 $text = preg_replace_callback(
1681 self::CHAR_REFS_REGEX,
1682 [ self::class, 'decodeCharReferencesCallback' ],
1683 $text,
1684 -1, //limit
1685 $count
1686 );
1687
1688 if ( $count ) {
1689 return MediaWikiServices::getInstance()->getContentLanguage()->normalize( $text );
1690 } else {
1691 return $text;
1692 }
1693 }
1694
1695 /**
1696 * @param string $matches
1697 * @return string
1698 */
1699 static function decodeCharReferencesCallback( $matches ) {
1700 if ( $matches[1] != '' ) {
1701 return self::decodeEntity( $matches[1] );
1702 } elseif ( $matches[2] != '' ) {
1703 return self::decodeChar( intval( $matches[2] ) );
1704 } elseif ( $matches[3] != '' ) {
1705 return self::decodeChar( hexdec( $matches[3] ) );
1706 }
1707 # Last case should be an ampersand by itself
1708 return $matches[0];
1709 }
1710
1711 /**
1712 * Return UTF-8 string for a codepoint if that is a valid
1713 * character reference, otherwise U+FFFD REPLACEMENT CHARACTER.
1714 * @param int $codepoint
1715 * @return string
1716 * @private
1717 */
1718 static function decodeChar( $codepoint ) {
1719 if ( self::validateCodepoint( $codepoint ) ) {
1720 return UtfNormal\Utils::codepointToUtf8( $codepoint );
1721 } else {
1722 return UtfNormal\Constants::UTF8_REPLACEMENT;
1723 }
1724 }
1725
1726 /**
1727 * If the named entity is defined in the HTML 4.0/XHTML 1.0 DTD,
1728 * return the UTF-8 encoding of that character. Otherwise, returns
1729 * pseudo-entity source (eg "&foo;")
1730 *
1731 * @param string $name
1732 * @return string
1733 */
1734 static function decodeEntity( $name ) {
1735 if ( isset( self::$htmlEntityAliases[$name] ) ) {
1736 $name = self::$htmlEntityAliases[$name];
1737 }
1738 if ( isset( self::$htmlEntities[$name] ) ) {
1739 return UtfNormal\Utils::codepointToUtf8( self::$htmlEntities[$name] );
1740 } else {
1741 return "&$name;";
1742 }
1743 }
1744
1745 /**
1746 * Fetch the whitelist of acceptable attributes for a given element name.
1747 *
1748 * @param string $element
1749 * @return array
1750 */
1751 static function attributeWhitelist( $element ) {
1752 $list = self::setupAttributeWhitelist();
1753 return $list[$element] ?? [];
1754 }
1755
1756 /**
1757 * Foreach array key (an allowed HTML element), return an array
1758 * of allowed attributes
1759 * @return array
1760 */
1761 static function setupAttributeWhitelist() {
1762 static $whitelist;
1763
1764 if ( $whitelist !== null ) {
1765 return $whitelist;
1766 }
1767
1768 $common = [
1769 # HTML
1770 'id',
1771 'class',
1772 'style',
1773 'lang',
1774 'dir',
1775 'title',
1776
1777 # WAI-ARIA
1778 'aria-describedby',
1779 'aria-flowto',
1780 'aria-label',
1781 'aria-labelledby',
1782 'aria-owns',
1783 'role',
1784
1785 # RDFa
1786 # These attributes are specified in section 9 of
1787 # https://www.w3.org/TR/2008/REC-rdfa-syntax-20081014
1788 'about',
1789 'property',
1790 'resource',
1791 'datatype',
1792 'typeof',
1793
1794 # Microdata. These are specified by
1795 # https://html.spec.whatwg.org/multipage/microdata.html#the-microdata-model
1796 'itemid',
1797 'itemprop',
1798 'itemref',
1799 'itemscope',
1800 'itemtype',
1801 ];
1802
1803 $block = array_merge( $common, [ 'align' ] );
1804 $tablealign = [ 'align', 'valign' ];
1805 $tablecell = [
1806 'abbr',
1807 'axis',
1808 'headers',
1809 'scope',
1810 'rowspan',
1811 'colspan',
1812 'nowrap', # deprecated
1813 'width', # deprecated
1814 'height', # deprecated
1815 'bgcolor', # deprecated
1816 ];
1817
1818 # Numbers refer to sections in HTML 4.01 standard describing the element.
1819 # See: https://www.w3.org/TR/html4/
1820 $whitelist = [
1821 # 7.5.4
1822 'div' => $block,
1823 'center' => $common, # deprecated
1824 'span' => $common,
1825
1826 # 7.5.5
1827 'h1' => $block,
1828 'h2' => $block,
1829 'h3' => $block,
1830 'h4' => $block,
1831 'h5' => $block,
1832 'h6' => $block,
1833
1834 # 7.5.6
1835 # address
1836
1837 # 8.2.4
1838 'bdo' => $common,
1839
1840 # 9.2.1
1841 'em' => $common,
1842 'strong' => $common,
1843 'cite' => $common,
1844 'dfn' => $common,
1845 'code' => $common,
1846 'samp' => $common,
1847 'kbd' => $common,
1848 'var' => $common,
1849 'abbr' => $common,
1850 # acronym
1851
1852 # 9.2.2
1853 'blockquote' => array_merge( $common, [ 'cite' ] ),
1854 'q' => array_merge( $common, [ 'cite' ] ),
1855
1856 # 9.2.3
1857 'sub' => $common,
1858 'sup' => $common,
1859
1860 # 9.3.1
1861 'p' => $block,
1862
1863 # 9.3.2
1864 'br' => array_merge( $common, [ 'clear' ] ),
1865
1866 # https://www.w3.org/TR/html5/text-level-semantics.html#the-wbr-element
1867 'wbr' => $common,
1868
1869 # 9.3.4
1870 'pre' => array_merge( $common, [ 'width' ] ),
1871
1872 # 9.4
1873 'ins' => array_merge( $common, [ 'cite', 'datetime' ] ),
1874 'del' => array_merge( $common, [ 'cite', 'datetime' ] ),
1875
1876 # 10.2
1877 'ul' => array_merge( $common, [ 'type' ] ),
1878 'ol' => array_merge( $common, [ 'type', 'start', 'reversed' ] ),
1879 'li' => array_merge( $common, [ 'type', 'value' ] ),
1880
1881 # 10.3
1882 'dl' => $common,
1883 'dd' => $common,
1884 'dt' => $common,
1885
1886 # 11.2.1
1887 'table' => array_merge( $common,
1888 [ 'summary', 'width', 'border', 'frame',
1889 'rules', 'cellspacing', 'cellpadding',
1890 'align', 'bgcolor',
1891 ] ),
1892
1893 # 11.2.2
1894 'caption' => $block,
1895
1896 # 11.2.3
1897 'thead' => $common,
1898 'tfoot' => $common,
1899 'tbody' => $common,
1900
1901 # 11.2.4
1902 'colgroup' => array_merge( $common, [ 'span' ] ),
1903 'col' => array_merge( $common, [ 'span' ] ),
1904
1905 # 11.2.5
1906 'tr' => array_merge( $common, [ 'bgcolor' ], $tablealign ),
1907
1908 # 11.2.6
1909 'td' => array_merge( $common, $tablecell, $tablealign ),
1910 'th' => array_merge( $common, $tablecell, $tablealign ),
1911
1912 # 12.2
1913 # NOTE: <a> is not allowed directly, but the attrib
1914 # whitelist is used from the Parser object
1915 'a' => array_merge( $common, [ 'href', 'rel', 'rev' ] ), # rel/rev esp. for RDFa
1916
1917 # 13.2
1918 # Not usually allowed, but may be used for extension-style hooks
1919 # such as <math> when it is rasterized, or if $wgAllowImageTag is
1920 # true
1921 'img' => array_merge( $common, [ 'alt', 'src', 'width', 'height', 'srcset' ] ),
1922 # Attributes for A/V tags added in T163583 / T133673
1923 'audio' => array_merge( $common, [ 'controls', 'preload', 'width', 'height' ] ),
1924 'video' => array_merge( $common, [ 'poster', 'controls', 'preload', 'width', 'height' ] ),
1925 'source' => array_merge( $common, [ 'type', 'src' ] ),
1926 'track' => array_merge( $common, [ 'type', 'src', 'srclang', 'kind', 'label' ] ),
1927
1928 # 15.2.1
1929 'tt' => $common,
1930 'b' => $common,
1931 'i' => $common,
1932 'big' => $common,
1933 'small' => $common,
1934 'strike' => $common,
1935 's' => $common,
1936 'u' => $common,
1937
1938 # 15.2.2
1939 'font' => array_merge( $common, [ 'size', 'color', 'face' ] ),
1940 # basefont
1941
1942 # 15.3
1943 'hr' => array_merge( $common, [ 'width' ] ),
1944
1945 # HTML Ruby annotation text module, simple ruby only.
1946 # https://www.w3.org/TR/html5/text-level-semantics.html#the-ruby-element
1947 'ruby' => $common,
1948 # rbc
1949 'rb' => $common,
1950 'rp' => $common,
1951 'rt' => $common, # array_merge( $common, array( 'rbspan' ) ),
1952 'rtc' => $common,
1953
1954 # MathML root element, where used for extensions
1955 # 'title' may not be 100% valid here; it's XHTML
1956 # https://www.w3.org/TR/REC-MathML/
1957 'math' => [ 'class', 'style', 'id', 'title' ],
1958
1959 // HTML 5 section 4.5
1960 'figure' => $common,
1961 'figure-inline' => $common, # T118520
1962 'figcaption' => $common,
1963
1964 # HTML 5 section 4.6
1965 'bdi' => $common,
1966
1967 # HTML5 elements, defined by:
1968 # https://html.spec.whatwg.org/multipage/semantics.html#the-data-element
1969 'data' => array_merge( $common, [ 'value' ] ),
1970 'time' => array_merge( $common, [ 'datetime' ] ),
1971 'mark' => $common,
1972
1973 // meta and link are only permitted by removeHTMLtags when Microdata
1974 // is enabled so we don't bother adding a conditional to hide these
1975 // Also meta and link are only valid in WikiText as Microdata elements
1976 // (ie: validateTag rejects tags missing the attributes needed for Microdata)
1977 // So we don't bother including $common attributes that have no purpose.
1978 'meta' => [ 'itemprop', 'content' ],
1979 'link' => [ 'itemprop', 'href', 'title' ],
1980 ];
1981
1982 return $whitelist;
1983 }
1984
1985 /**
1986 * Take a fragment of (potentially invalid) HTML and return
1987 * a version with any tags removed, encoded as plain text.
1988 *
1989 * Warning: this return value must be further escaped for literal
1990 * inclusion in HTML output as of 1.10!
1991 *
1992 * @param string $html HTML fragment
1993 * @return string
1994 */
1995 static function stripAllTags( $html ) {
1996 // Use RemexHtml to tokenize $html and extract the text
1997 $handler = new RemexStripTagHandler;
1998 $tokenizer = new RemexHtml\Tokenizer\Tokenizer( $handler, $html, [
1999 'ignoreErrors' => true,
2000 // don't ignore char refs, we want them to be decoded
2001 'ignoreNulls' => true,
2002 'skipPreprocess' => true,
2003 ] );
2004 $tokenizer->execute();
2005 $text = $handler->getResult();
2006
2007 $text = self::normalizeWhitespace( $text );
2008 return $text;
2009 }
2010
2011 /**
2012 * Hack up a private DOCTYPE with HTML's standard entity declarations.
2013 * PHP 4 seemed to know these if you gave it an HTML doctype, but
2014 * PHP 5.1 doesn't.
2015 *
2016 * Use for passing XHTML fragments to PHP's XML parsing functions
2017 *
2018 * @return string
2019 */
2020 static function hackDocType() {
2021 $out = "<!DOCTYPE html [\n";
2022 foreach ( self::$htmlEntities as $entity => $codepoint ) {
2023 $out .= "<!ENTITY $entity \"&#$codepoint;\">";
2024 }
2025 $out .= "]>\n";
2026 return $out;
2027 }
2028
2029 /**
2030 * @param string $url
2031 * @return mixed|string
2032 */
2033 static function cleanUrl( $url ) {
2034 # Normalize any HTML entities in input. They will be
2035 # re-escaped by makeExternalLink().
2036 $url = self::decodeCharReferences( $url );
2037
2038 # Escape any control characters introduced by the above step
2039 $url = preg_replace_callback( '/[\][<>"\\x00-\\x20\\x7F\|]/',
2040 [ __CLASS__, 'cleanUrlCallback' ], $url );
2041
2042 # Validate hostname portion
2043 $matches = [];
2044 if ( preg_match( '!^([^:]+:)(//[^/]+)?(.*)$!iD', $url, $matches ) ) {
2045 list( /* $whole */, $protocol, $host, $rest ) = $matches;
2046
2047 // Characters that will be ignored in IDNs.
2048 // https://tools.ietf.org/html/rfc3454#section-3.1
2049 // Strip them before further processing so blacklists and such work.
2050 $strip = "/
2051 \\s| # general whitespace
2052 \xc2\xad| # 00ad SOFT HYPHEN
2053 \xe1\xa0\x86| # 1806 MONGOLIAN TODO SOFT HYPHEN
2054 \xe2\x80\x8b| # 200b ZERO WIDTH SPACE
2055 \xe2\x81\xa0| # 2060 WORD JOINER
2056 \xef\xbb\xbf| # feff ZERO WIDTH NO-BREAK SPACE
2057 \xcd\x8f| # 034f COMBINING GRAPHEME JOINER
2058 \xe1\xa0\x8b| # 180b MONGOLIAN FREE VARIATION SELECTOR ONE
2059 \xe1\xa0\x8c| # 180c MONGOLIAN FREE VARIATION SELECTOR TWO
2060 \xe1\xa0\x8d| # 180d MONGOLIAN FREE VARIATION SELECTOR THREE
2061 \xe2\x80\x8c| # 200c ZERO WIDTH NON-JOINER
2062 \xe2\x80\x8d| # 200d ZERO WIDTH JOINER
2063 [\xef\xb8\x80-\xef\xb8\x8f] # fe00-fe0f VARIATION SELECTOR-1-16
2064 /xuD";
2065
2066 $host = preg_replace( $strip, '', $host );
2067
2068 // IPv6 host names are bracketed with []. Url-decode these.
2069 if ( substr_compare( "//%5B", $host, 0, 5 ) === 0 &&
2070 preg_match( '!^//%5B([0-9A-Fa-f:.]+)%5D((:\d+)?)$!', $host, $matches )
2071 ) {
2072 $host = '//[' . $matches[1] . ']' . $matches[2];
2073 }
2074
2075 // @todo FIXME: Validate hostnames here
2076
2077 return $protocol . $host . $rest;
2078 } else {
2079 return $url;
2080 }
2081 }
2082
2083 /**
2084 * @param array $matches
2085 * @return string
2086 */
2087 static function cleanUrlCallback( $matches ) {
2088 return urlencode( $matches[0] );
2089 }
2090
2091 /**
2092 * Does a string look like an e-mail address?
2093 *
2094 * This validates an email address using an HTML5 specification found at:
2095 * http://www.whatwg.org/html/states-of-the-type-attribute.html#valid-e-mail-address
2096 * Which as of 2011-01-24 says:
2097 *
2098 * A valid e-mail address is a string that matches the ABNF production
2099 * 1*( atext / "." ) "@" ldh-str *( "." ldh-str ) where atext is defined
2100 * in RFC 5322 section 3.2.3, and ldh-str is defined in RFC 1034 section
2101 * 3.5.
2102 *
2103 * This function is an implementation of the specification as requested in
2104 * T24449.
2105 *
2106 * Client-side forms will use the same standard validation rules via JS or
2107 * HTML 5 validation; additional restrictions can be enforced server-side
2108 * by extensions via the 'isValidEmailAddr' hook.
2109 *
2110 * Note that this validation doesn't 100% match RFC 2822, but is believed
2111 * to be liberal enough for wide use. Some invalid addresses will still
2112 * pass validation here.
2113 *
2114 * @since 1.18
2115 *
2116 * @param string $addr E-mail address
2117 * @return bool
2118 */
2119 public static function validateEmail( $addr ) {
2120 $result = null;
2121 if ( !Hooks::run( 'isValidEmailAddr', [ $addr, &$result ] ) ) {
2122 return $result;
2123 }
2124
2125 // Please note strings below are enclosed in brackets [], this make the
2126 // hyphen "-" a range indicator. Hence it is double backslashed below.
2127 // See T28948
2128 $rfc5322_atext = "a-z0-9!#$%&'*+\\-\/=?^_`{|}~";
2129 $rfc1034_ldh_str = "a-z0-9\\-";
2130
2131 $html5_email_regexp = "/
2132 ^ # start of string
2133 [$rfc5322_atext\\.]+ # user part which is liberal :p
2134 @ # 'apostrophe'
2135 [$rfc1034_ldh_str]+ # First domain part
2136 (\\.[$rfc1034_ldh_str]+)* # Following part prefixed with a dot
2137 $ # End of string
2138 /ix"; // case Insensitive, eXtended
2139
2140 return (bool)preg_match( $html5_email_regexp, $addr );
2141 }
2142 }
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