netwerk/dns/src/nsIDNService.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 2002
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Naoki Hotta <nhotta@netscape.com> (original author)
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include "nsIDNService.h"
  40 #include "nsReadableUtils.h"
  41 #include "nsCRT.h"
  42 #include "nsUnicharUtils.h"
  43 #include "nsIServiceManager.h"
  44 #include "nsIPrefService.h"
  45 #include "nsIPrefBranch.h"
  46 #include "nsIPrefBranch2.h"
  47 #include "nsIObserverService.h"
  48 #include "nsISupportsPrimitives.h"
  49 #include "punycode.h"
  50
  51 //-----------------------------------------------------------------------------
  52 // RFC 1034 - 3.1. Name space specifications and terminology
  53 static const PRUint32 kMaxDNSNodeLen = 63;
  54
  55 //-----------------------------------------------------------------------------
  56
  57 #define NS_NET_PREF_IDNTESTBED      "network.IDN_testbed"
  58 #define NS_NET_PREF_IDNPREFIX       "network.IDN_prefix"
  59 #define NS_NET_PREF_IDNBLACKLIST    "network.IDN.blacklist_chars"
  60 #define NS_NET_PREF_SHOWPUNYCODE    "network.IDN_show_punycode"
  61 #define NS_NET_PREF_IDNWHITELIST    "network.IDN.whitelist."
  62
  63 inline PRBool isOnlySafeChars(const nsAFlatString& in,
  64                               const nsAFlatString& blacklist)
  65 {
  66   return (blacklist.IsEmpty() ||
  67           in.FindCharInSet(blacklist) == kNotFound);
  68 }
  69
  70 //-----------------------------------------------------------------------------
  71 // nsIDNService
  72 //-----------------------------------------------------------------------------
  73
  74 /* Implementation file */
  75 NS_IMPL_THREADSAFE_ISUPPORTS3(nsIDNService,
  76                               nsIIDNService,
  77                               nsIObserver,
  78                               nsISupportsWeakReference)
  79
  80 nsresult nsIDNService::Init()
  81 {
  82   nsCOMPtr<nsIPrefService> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
  83   if (prefs)
  84     prefs->GetBranch(NS_NET_PREF_IDNWHITELIST, getter_AddRefs(mIDNWhitelistPrefBranch));
  85
  86   nsCOMPtr<nsIPrefBranch2> prefInternal(do_QueryInterface(prefs));
  87   if (prefInternal) {
  88     prefInternal->AddObserver(NS_NET_PREF_IDNTESTBED, this, PR_TRUE);
  89     prefInternal->AddObserver(NS_NET_PREF_IDNPREFIX, this, PR_TRUE);
  90     prefInternal->AddObserver(NS_NET_PREF_IDNBLACKLIST, this, PR_TRUE);
  91     prefInternal->AddObserver(NS_NET_PREF_SHOWPUNYCODE, this, PR_TRUE);
  92     prefsChanged(prefInternal, nsnull);
  93   }
  94
  95   return NS_OK;
  96 }
  97
  98 NS_IMETHODIMP nsIDNService::Observe(nsISupports *aSubject,
  99                                     const char *aTopic,
 100                                     const PRUnichar *aData)
 101 {
 102   if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {
 103     nsCOMPtr<nsIPrefBranch> prefBranch( do_QueryInterface(aSubject) );
 104     if (prefBranch)
 105       prefsChanged(prefBranch, aData);
 106   }
 107   return NS_OK;
 108 }
 109
 110 void nsIDNService::prefsChanged(nsIPrefBranch *prefBranch, const PRUnichar *pref)
 111 {
 112   if (!pref || NS_LITERAL_STRING(NS_NET_PREF_IDNTESTBED).Equals(pref)) {
 113     PRBool val;
 114     if (NS_SUCCEEDED(prefBranch->GetBoolPref(NS_NET_PREF_IDNTESTBED, &val)))
 115       mMultilingualTestBed = val;
 116   }
 117   if (!pref || NS_LITERAL_STRING(NS_NET_PREF_IDNPREFIX).Equals(pref)) {
 118     nsXPIDLCString prefix;
 119     nsresult rv = prefBranch->GetCharPref(NS_NET_PREF_IDNPREFIX, getter_Copies(prefix));
 120     if (NS_SUCCEEDED(rv) && prefix.Length() <= kACEPrefixLen)
 121       PL_strncpyz(nsIDNService::mACEPrefix, prefix.get(), kACEPrefixLen + 1);
 122   }
 123   if (!pref || NS_LITERAL_STRING(NS_NET_PREF_IDNBLACKLIST).Equals(pref)) {
 124     nsCOMPtr<nsISupportsString> blacklist;
 125     nsresult rv = prefBranch->GetComplexValue(NS_NET_PREF_IDNBLACKLIST,
 126                                               NS_GET_IID(nsISupportsString),
 127                                               getter_AddRefs(blacklist));
 128     if (NS_SUCCEEDED(rv))
 129       blacklist->ToString(getter_Copies(mIDNBlacklist));
 130     else
 131       mIDNBlacklist.Truncate();
 132   }
 133   if (!pref || NS_LITERAL_STRING(NS_NET_PREF_SHOWPUNYCODE).Equals(pref)) {
 134     PRBool val;
 135     if (NS_SUCCEEDED(prefBranch->GetBoolPref(NS_NET_PREF_SHOWPUNYCODE, &val)))
 136       mShowPunycode = val;
 137   }
 138 }
 139
 140 nsIDNService::nsIDNService()
 141 {
 142   // initialize to the official prefix (RFC 3490 "5. ACE prefix")
 143   const char kIDNSPrefix[] = "xn--";
 144   strcpy(mACEPrefix, kIDNSPrefix);
 145
 146   mMultilingualTestBed = PR_FALSE;
 147
 148   if (idn_success != idn_nameprep_create(NULL, &mNamePrepHandle))
 149     mNamePrepHandle = nsnull;
 150
 151   mNormalizer = do_GetService(NS_UNICODE_NORMALIZER_CONTRACTID);
 152   /* member initializers and constructor code */
 153 }
 154
 155 nsIDNService::~nsIDNService()
 156 {
 157   idn_nameprep_destroy(mNamePrepHandle);
 158 }
 159
 160 /* ACString ConvertUTF8toACE (in AUTF8String input); */
 161 NS_IMETHODIMP nsIDNService::ConvertUTF8toACE(const nsACString & input, nsACString & ace)
 162 {
 163   nsresult rv;
 164   NS_ConvertUTF8toUTF16 ustr(input);
 165
 166   // map ideographic period to ASCII period etc.
 167   normalizeFullStops(ustr);
 168
 169
 170   PRUint32 len, offset;
 171   len = 0;
 172   offset = 0;
 173   nsCAutoString encodedBuf;
 174
 175   nsAString::const_iterator start, end;
 176   ustr.BeginReading(start);
 177   ustr.EndReading(end);
 178   ace.Truncate();
 179
 180   // encode nodes if non ASCII
 181   while (start != end) {
 182     len++;
 183     if (*start++ == (PRUnichar)'.') {
 184       rv = stringPrepAndACE(Substring(ustr, offset, len - 1), encodedBuf);
 185       NS_ENSURE_SUCCESS(rv, rv);
 186
 187       ace.Append(encodedBuf);
 188       ace.Append('.');
 189       offset += len;
 190       len = 0;
 191     }
 192   }
 193
 194   // add extra node for multilingual test bed
 195   if (mMultilingualTestBed)
 196     ace.AppendLiteral("mltbd.");
 197   // encode the last node if non ASCII
 198   if (len) {
 199     rv = stringPrepAndACE(Substring(ustr, offset, len), encodedBuf);
 200     NS_ENSURE_SUCCESS(rv, rv);
 201
 202     ace.Append(encodedBuf);
 203   }
 204
 205   return NS_OK;
 206 }
 207
 208 /* AUTF8String convertACEtoUTF8(in ACString input); */
 209 NS_IMETHODIMP nsIDNService::ConvertACEtoUTF8(const nsACString & input, nsACString & _retval)
 210 {
 211   // RFC 3490 - 4.2 ToUnicode
 212   // ToUnicode never fails.  If any step fails, then the original input
 213   // sequence is returned immediately in that step.
 214
 215   if (!IsASCII(input)) {
 216     _retval.Assign(input);
 217     return NS_OK;
 218   }
 219
 220   PRUint32 len = 0, offset = 0;
 221   nsCAutoString decodedBuf;
 222
 223   nsACString::const_iterator start, end;
 224   input.BeginReading(start);
 225   input.EndReading(end);
 226   _retval.Truncate();
 227
 228   // loop and decode nodes
 229   while (start != end) {
 230     len++;
 231     if (*start++ == '.') {
 232       if (NS_FAILED(decodeACE(Substring(input, offset, len - 1), decodedBuf))) {
 233         _retval.Assign(input);
 234         return NS_OK;
 235       }
 236
 237       _retval.Append(decodedBuf);
 238       _retval.Append('.');
 239       offset += len;
 240       len = 0;
 241     }
 242   }
 243   // decode the last node
 244   if (len) {
 245     if (NS_FAILED(decodeACE(Substring(input, offset, len), decodedBuf)))
 246       _retval.Assign(input);
 247     else
 248       _retval.Append(decodedBuf);
 249   }
 250
 251   return NS_OK;
 252 }
 253
 254 /* boolean isACE(in ACString input); */
 255 NS_IMETHODIMP nsIDNService::IsACE(const nsACString & input, PRBool *_retval)
 256 {
 257   nsACString::const_iterator begin;
 258   input.BeginReading(begin);
 259
 260   const char *data = begin.get();
 261   PRUint32 dataLen = begin.size_forward();
 262
 263   // look for the ACE prefix in the input string.  it may occur
 264   // at the beginning of any segment in the domain name.  for
 265   // example: "www.xn--ENCODED.com"
 266
 267   const char *p = PL_strncasestr(data, mACEPrefix, dataLen);
 268
 269   *_retval = p && (p == data || *(p - 1) == '.');
 270   return NS_OK;
 271 }
 272
 273 /* AUTF8String normalize(in AUTF8String input); */
 274 NS_IMETHODIMP nsIDNService::Normalize(const nsACString & input, nsACString & output)
 275 {
 276   // protect against bogus input
 277   NS_ENSURE_TRUE(IsUTF8(input), NS_ERROR_UNEXPECTED);
 278
 279   NS_ConvertUTF8toUTF16 inUTF16(input);
 280   normalizeFullStops(inUTF16);
 281
 282   // pass the domain name to stringprep label by label
 283   nsAutoString outUTF16, outLabel;
 284
 285   PRUint32 len = 0, offset = 0;
 286   nsresult rv;
 287   nsAString::const_iterator start, end;
 288   inUTF16.BeginReading(start);
 289   inUTF16.EndReading(end);
 290
 291   while (start != end) {
 292     len++;
 293     if (*start++ == PRUnichar('.')) {
 294       rv = stringPrep(Substring(inUTF16, offset, len - 1), outLabel);
 295       NS_ENSURE_SUCCESS(rv, rv);
 296
 297       outUTF16.Append(outLabel);
 298       outUTF16.Append(PRUnichar('.'));
 299       offset += len;
 300       len = 0;
 301     }
 302   }
 303   if (len) {
 304     rv = stringPrep(Substring(inUTF16, offset, len), outLabel);
 305     NS_ENSURE_SUCCESS(rv, rv);
 306
 307     outUTF16.Append(outLabel);
 308   }
 309
 310   CopyUTF16toUTF8(outUTF16, output);
 311   if (!isOnlySafeChars(outUTF16, mIDNBlacklist))
 312     return ConvertUTF8toACE(output, output);
 313
 314   return NS_OK;
 315 }
 316
 317 NS_IMETHODIMP nsIDNService::ConvertToDisplayIDN(const nsACString & input, PRBool * _isASCII, nsACString & _retval)
 318 {
 319   // If host is ACE, then convert to UTF-8 if the host is in the IDN whitelist.
 320   // Else, if host is already UTF-8, then make sure it is normalized per IDN.
 321
 322   nsresult rv;
 323
 324   if (IsASCII(input)) {
 325     // first, canonicalize the host to lowercase, for whitelist lookup
 326     _retval = input;
 327     ToLowerCase(_retval);
 328
 329     PRBool isACE;
 330     IsACE(_retval, &isACE);
 331
 332     if (isACE && !mShowPunycode && isInWhitelist(_retval)) {
 333       // ConvertACEtoUTF8() can't fail, but might return the original ACE string
 334       nsCAutoString temp(_retval);
 335       ConvertACEtoUTF8(temp, _retval);
 336       *_isASCII = IsASCII(_retval);
 337     } else {
 338       *_isASCII = PR_TRUE;
 339     }
 340   } else {
 341     // We have to normalize the hostname before testing against the domain
 342     // whitelist (see bug 315411), and to ensure the entire string gets
 343     // normalized.
 344     rv = Normalize(input, _retval);
 345     if (NS_FAILED(rv)) return rv;
 346
 347     if (mShowPunycode && NS_SUCCEEDED(ConvertUTF8toACE(_retval, _retval))) {
 348       *_isASCII = PR_TRUE;
 349       return NS_OK;
 350     }
 351
 352     // normalization could result in an ASCII-only hostname. alternatively, if
 353     // the host is converted to ACE by the normalizer, then the host may contain
 354     // unsafe characters, so leave it ACE encoded. see bug 283016, bug 301694, and bug 309311.
 355     *_isASCII = IsASCII(_retval);
 356     if (!*_isASCII && !isInWhitelist(_retval)) {
 357       *_isASCII = PR_TRUE;
 358       return ConvertUTF8toACE(_retval, _retval);
 359     }
 360   }
 361
 362   return NS_OK;
 363 }
 364
 365 //-----------------------------------------------------------------------------
 366
 367 static void utf16ToUcs4(const nsAString& in, PRUint32 *out, PRUint32 outBufLen, PRUint32 *outLen)
 368 {
 369   PRUint32 i = 0;
 370   nsAString::const_iterator start, end;
 371   in.BeginReading(start);
 372   in.EndReading(end);
 373
 374   while (start != end) {
 375     PRUnichar curChar;
 376
 377     curChar= *start++;
 378
 379     if (start != end &&
 380         NS_IS_HIGH_SURROGATE(curChar) &&
 381         NS_IS_LOW_SURROGATE(*start)) {
 382       out[i] = SURROGATE_TO_UCS4(curChar, *start);
 383       ++start;
 384     }
 385     else
 386       out[i] = curChar;
 387
 388     i++;
 389     if (i >= outBufLen) {
 390       NS_ERROR("input too big, the result truncated");
 391       out[outBufLen-1] = (PRUint32)'\0';
 392       *outLen = outBufLen-1;
 393       return;
 394     }
 395   }
 396   out[i] = (PRUint32)'\0';
 397   *outLen = i;
 398 }
 399
 400 static void ucs4toUtf16(const PRUint32 *in, nsAString& out)
 401 {
 402   while (*in) {
 403     if (!IS_IN_BMP(*in)) {
 404       out.Append((PRUnichar) H_SURROGATE(*in));
 405       out.Append((PRUnichar) L_SURROGATE(*in));
 406     }
 407     else
 408       out.Append((PRUnichar) *in);
 409     in++;
 410   }
 411 }
 412
 413 static nsresult punycode(const char* prefix, const nsAString& in, nsACString& out)
 414 {
 415   PRUint32 ucs4Buf[kMaxDNSNodeLen + 1];
 416   PRUint32 ucs4Len;
 417   utf16ToUcs4(in, ucs4Buf, kMaxDNSNodeLen, &ucs4Len);
 418
 419   // need maximum 20 bits to encode 16 bit Unicode character
 420   // (include null terminator)
 421   const PRUint32 kEncodedBufSize = kMaxDNSNodeLen * 20 / 8 + 1 + 1;
 422   char encodedBuf[kEncodedBufSize];
 423   punycode_uint encodedLength = kEncodedBufSize;
 424
 425   enum punycode_status status = punycode_encode(ucs4Len,
 426                                                 ucs4Buf,
 427                                                 nsnull,
 428                                                 &encodedLength,
 429                                                 encodedBuf);
 430
 431   if (punycode_success != status ||
 432       encodedLength >= kEncodedBufSize)
 433     return NS_ERROR_FAILURE;
 434
 435   encodedBuf[encodedLength] = '\0';
 436   out.Assign(nsDependentCString(prefix) + nsDependentCString(encodedBuf));
 437
 438   return NS_OK;
 439 }
 440
 441 static nsresult encodeToRACE(const char* prefix, const nsAString& in, nsACString& out)
 442 {
 443   // need maximum 20 bits to encode 16 bit Unicode character
 444   // (include null terminator)
 445   const PRUint32 kEncodedBufSize = kMaxDNSNodeLen * 20 / 8 + 1 + 1;
 446
 447   // set up a work buffer for RACE encoder
 448   PRUnichar temp[kMaxDNSNodeLen + 2];
 449   temp[0] = 0xFFFF;   // set a place holder (to be filled by get_compress_mode)
 450   temp[in.Length() + 1] = (PRUnichar)'\0';
 451
 452   nsAString::const_iterator start, end;
 453   in.BeginReading(start);
 454   in.EndReading(end);
 455
 456   for (PRUint32 i = 1; start != end; i++)
 457     temp[i] = *start++;
 458
 459   // encode nodes if non ASCII
 460
 461   char encodedBuf[kEncodedBufSize];
 462   idn_result_t result = race_compress_encode((const unsigned short *) temp,
 463                                              get_compress_mode((unsigned short *) temp + 1),
 464                                              encodedBuf, kEncodedBufSize);
 465   if (idn_success != result)
 466     return NS_ERROR_FAILURE;
 467
 468   out.Assign(prefix);
 469   out.Append(encodedBuf);
 470
 471   return NS_OK;
 472 }
 473
 474 // RFC 3454
 475 //
 476 // 1) Map -- For each character in the input, check if it has a mapping
 477 // and, if so, replace it with its mapping. This is described in section 3.
 478 //
 479 // 2) Normalize -- Possibly normalize the result of step 1 using Unicode
 480 // normalization. This is described in section 4.
 481 //
 482 // 3) Prohibit -- Check for any characters that are not allowed in the
 483 // output. If any are found, return an error. This is described in section
 484 // 5.
 485 //
 486 // 4) Check bidi -- Possibly check for right-to-left characters, and if any
 487 // are found, make sure that the whole string satisfies the requirements
 488 // for bidirectional strings. If the string does not satisfy the requirements
 489 // for bidirectional strings, return an error. This is described in section 6.
 490 //
 491 nsresult nsIDNService::stringPrep(const nsAString& in, nsAString& out)
 492 {
 493   if (!mNamePrepHandle || !mNormalizer)
 494     return NS_ERROR_FAILURE;
 495
 496   nsresult rv = NS_OK;
 497   PRUint32 ucs4Buf[kMaxDNSNodeLen + 1];
 498   PRUint32 ucs4Len;
 499   utf16ToUcs4(in, ucs4Buf, kMaxDNSNodeLen, &ucs4Len);
 500
 501   // map
 502   idn_result_t idn_err;
 503
 504   PRUint32 namePrepBuf[kMaxDNSNodeLen * 3];   // map up to three characters
 505   idn_err = idn_nameprep_map(mNamePrepHandle, (const PRUint32 *) ucs4Buf,
 506                                      (PRUint32 *) namePrepBuf, kMaxDNSNodeLen * 3);
 507   NS_ENSURE_TRUE(idn_err == idn_success, NS_ERROR_FAILURE);
 508
 509   nsAutoString namePrepStr;
 510   ucs4toUtf16(namePrepBuf, namePrepStr);
 511   if (namePrepStr.Length() >= kMaxDNSNodeLen)
 512     return NS_ERROR_FAILURE;
 513
 514   // normalize
 515   nsAutoString normlizedStr;
 516   rv = mNormalizer->NormalizeUnicodeNFKC(namePrepStr, normlizedStr);
 517   if (normlizedStr.Length() >= kMaxDNSNodeLen)
 518     return NS_ERROR_FAILURE;
 519
 520   // prohibit
 521   const PRUint32 *found = nsnull;
 522   idn_err = idn_nameprep_isprohibited(mNamePrepHandle,
 523                                       (const PRUint32 *) ucs4Buf, &found);
 524   if (idn_err != idn_success || found)
 525     return NS_ERROR_FAILURE;
 526
 527   // check bidi
 528   idn_err = idn_nameprep_isvalidbidi(mNamePrepHandle,
 529                                      (const PRUint32 *) ucs4Buf, &found);
 530   if (idn_err != idn_success || found)
 531     return NS_ERROR_FAILURE;
 532
 533   // set the result string
 534   out.Assign(normlizedStr);
 535
 536   return rv;
 537 }
 538
 539 nsresult nsIDNService::encodeToACE(const nsAString& in, nsACString& out)
 540 {
 541   // RACE encode is supported for existing testing environment
 542   if (!strcmp("bq--", mACEPrefix))
 543     return encodeToRACE(mACEPrefix, in, out);
 544
 545   // use punycoce
 546   return punycode(mACEPrefix, in, out);
 547 }
 548
 549 nsresult nsIDNService::stringPrepAndACE(const nsAString& in, nsACString& out)
 550 {
 551   nsresult rv = NS_OK;
 552
 553   out.Truncate();
 554
 555   if (in.Length() > kMaxDNSNodeLen) {
 556     NS_ERROR("IDN node too large");
 557     return NS_ERROR_FAILURE;
 558   }
 559
 560   if (IsASCII(in))
 561     LossyCopyUTF16toASCII(in, out);
 562   else {
 563     nsAutoString strPrep;
 564     rv = stringPrep(in, strPrep);
 565     if (NS_SUCCEEDED(rv)) {
 566       if (IsASCII(strPrep))
 567         LossyCopyUTF16toASCII(strPrep, out);
 568       else
 569         rv = encodeToACE(strPrep, out);
 570     }
 571   }
 572
 573   if (out.Length() > kMaxDNSNodeLen) {
 574     NS_ERROR("IDN node too large");
 575     return NS_ERROR_FAILURE;
 576   }
 577
 578   return rv;
 579 }
 580
 581 // RFC 3490
 582 // 1) Whenever dots are used as label separators, the following characters
 583 //    MUST be recognized as dots: U+002E (full stop), U+3002 (ideographic full
 584 //    stop), U+FF0E (fullwidth full stop), U+FF61 (halfwidth ideographic full
 585 //    stop).
 586
 587 void nsIDNService::normalizeFullStops(nsAString& s)
 588 {
 589   nsAString::const_iterator start, end;
 590   s.BeginReading(start);
 591   s.EndReading(end);
 592   PRInt32 index = 0;
 593
 594   while (start != end) {
 595     switch (*start) {
 596       case 0x3002:
 597       case 0xFF0E:
 598       case 0xFF61:
 599         s.Replace(index, 1, NS_LITERAL_STRING("."));
 600         break;
 601       default:
 602         break;
 603     }
 604     start++;
 605     index++;
 606   }
 607 }
 608
 609 nsresult nsIDNService::decodeACE(const nsACString& in, nsACString& out)
 610 {
 611   PRBool isAce;
 612   IsACE(in, &isAce);
 613   if (!isAce) {
 614     out.Assign(in);
 615     return NS_OK;
 616   }
 617
 618   // RFC 3490 - 4.2 ToUnicode
 619   // The ToUnicode output never contains more code points than its input.
 620   punycode_uint output_length = in.Length() - kACEPrefixLen + 1;
 621   punycode_uint *output = new punycode_uint[output_length];
 622   NS_ENSURE_TRUE(output, NS_ERROR_OUT_OF_MEMORY);
 623
 624   enum punycode_status status = punycode_decode(in.Length() - kACEPrefixLen,
 625                                                 PromiseFlatCString(in).get() + kACEPrefixLen,
 626                                                 &output_length,
 627                                                 output,
 628                                                 nsnull);
 629   if (status != punycode_success) {
 630     delete [] output;
 631     return NS_ERROR_FAILURE;
 632   }
 633
 634   // UCS4 -> UTF8
 635   output[output_length] = 0;
 636   nsAutoString utf16;
 637   ucs4toUtf16(output, utf16);
 638   delete [] output;
 639   if (!isOnlySafeChars(utf16, mIDNBlacklist))
 640     return NS_ERROR_FAILURE;
 641   CopyUTF16toUTF8(utf16, out);
 642
 643   // Validation: encode back to ACE and compare the strings
 644   nsCAutoString ace;
 645   nsresult rv = ConvertUTF8toACE(out, ace);
 646   NS_ENSURE_SUCCESS(rv, rv);
 647
 648   if (!ace.Equals(in, nsCaseInsensitiveCStringComparator()))
 649     return NS_ERROR_FAILURE;
 650
 651   return NS_OK;
 652 }
 653
 654 PRBool nsIDNService::isInWhitelist(const nsACString &host)
 655 {
 656   if (mIDNWhitelistPrefBranch) {
 657     // truncate trailing dots first
 658     nsCAutoString tld(host);
 659     tld.Trim(".");
 660     PRInt32 pos = tld.RFind(".");
 661     if (pos == kNotFound)
 662       return PR_FALSE;
 663
 664     tld.Cut(0, pos + 1);
 665
 666     // make sure the TLD is ACE for lookup.
 667     if (!IsASCII(tld) &&
 668         NS_FAILED(ConvertUTF8toACE(tld, tld)))
 669       return PR_FALSE;
 670
 671     PRBool safe;
 672     if (NS_SUCCEEDED(mIDNWhitelistPrefBranch->GetBoolPref(tld.get(), &safe)))
 673       return safe;
 674   }
 675
 676   return PR_FALSE;
 677 }
 678