netwerk/dns/IDNBlocklistUtils.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "IDNBlocklistUtils.h"
   6
   7 #include "mozilla/Preferences.h"
   8 #include "nsStringFwd.h"
   9
  10 namespace mozilla {
  11 namespace net {
  12
  13 static constexpr char16_t sBlocklistPairs[][2] = {
  14 #include "IDNCharacterBlocklist.inc"
  15 };
  16
  17 void RemoveCharFromBlocklist(char16_t aChar,
  18                              nsTArray<BlocklistRange>& aBlocklist) {
  19   auto pos = aBlocklist.BinaryIndexOf(aChar, BlocklistPairToCharComparator());
  20   if (pos == nsTArray<BlocklistRange>::NoIndex) {
  21     return;
  22   }
  23
  24   auto& pair = aBlocklist[pos];
  25
  26   // If the matched range has a length of one, we can just remove it
  27   if (pair.second == pair.first) {
  28     aBlocklist.RemoveElementAt(pos);
  29     return;
  30   }
  31
  32   // If the character matches the first element in the range, just update
  33   // the range.
  34   if (aChar == pair.first) {
  35     pair.first = pair.first + 1;
  36     return;
  37   }
  38
  39   // Also if it matches the last character in the range, we just update it.
  40   if (aChar == pair.second) {
  41     pair.second = pair.second - 1;
  42     return;
  43   }
  44
  45   // Our character is in the middle of the range, splitting it in two.
  46   // We update the matched range to reflect the values before the character,
  47   // and insert a new range that represents the values after.
  48   char16_t lastElement = pair.second;
  49   pair.second = aChar - 1;
  50   aBlocklist.InsertElementAt(pos + 1,
  51                              std::make_pair(char16_t(aChar + 1), lastElement));
  52 }
  53
  54 void InitializeBlocklist(nsTArray<BlocklistRange>& aBlocklist) {
  55   aBlocklist.Clear();
  56   for (auto const& arr : sBlocklistPairs) {
  57     // The hardcoded pairs are already sorted.
  58     aBlocklist.AppendElement(std::make_pair(arr[0], arr[1]));
  59   }
  60
  61   nsAutoString extraAllowed;
  62   nsresult rv =
  63       Preferences::GetString("network.IDN.extra_allowed_chars", extraAllowed);
  64   if (NS_SUCCEEDED(rv) && !extraAllowed.IsEmpty()) {
  65     const char16_t* cur = extraAllowed.BeginReading();
  66     const char16_t* end = extraAllowed.EndReading();
  67     // Characters in the allowed list are removed from the blocklist.
  68     for (; cur < end; ++cur) {
  69       RemoveCharFromBlocklist(*cur, aBlocklist);
  70     }
  71   }
  72
  73   nsAutoString extraBlocked;
  74   rv = Preferences::GetString("network.IDN.extra_blocked_chars", extraBlocked);
  75   // We add each extra blocked character to the blocklist as a separate range.
  76   if (NS_SUCCEEDED(rv) && !extraBlocked.IsEmpty()) {
  77     for (size_t i = 0; i < extraBlocked.Length(); ++i) {
  78       aBlocklist.AppendElement(
  79           std::make_pair(extraBlocked[i], extraBlocked[i]));
  80     }
  81     aBlocklist.Sort(BlocklistEntryComparator());
  82   }
  83 }
  84
  85 }  // namespace net
  86 }  // namespace mozilla