xpcom/string/nsTDependentString.cpp
author Honza Bambas <honzab.moz@firemni.cz>
Tue, 21 Feb 2017 11:38:00 -0500
changeset 391534 3e552501cd1fc10a5c5e41fdc87c8161453cf8f0
parent 255491 20729b28eb1e1d7f0d9e9e6e2c61e7050f09884f
child 416817 a431a8ff8f574447b197954304e3658c46e6a42a
permissions -rw-r--r--
Bug 1340577 - Add release-grade assertions to various XPCOM string API implementations to avoid input causing an overflow. r=froydnj

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

nsTDependentString_CharT::nsTDependentString_CharT(const char_type* aStart,
                                                   const char_type* aEnd)
  : string_type(const_cast<char_type*>(aStart),
                uint32_t(aEnd - aStart), F_TERMINATED)
{
  MOZ_RELEASE_ASSERT(aStart <= aEnd, "Overflow!");
  AssertValidDependentString();
}

void
nsTDependentString_CharT::Rebind(const string_type& str, uint32_t startPos)
{
  MOZ_ASSERT(str.Flags() & F_TERMINATED, "Unterminated flat string");

  // If we currently own a buffer, release it.
  Finalize();

  size_type strLength = str.Length();

  if (startPos > strLength) {
    startPos = strLength;
  }

  mData = const_cast<char_type*>(static_cast<const char_type*>(str.Data())) + startPos;
  mLength = strLength - startPos;

  SetDataFlags(str.Flags() & (F_TERMINATED | F_LITERAL));
}

void
nsTDependentString_CharT::Rebind(const char_type* aStart, const char_type* aEnd)
{
  MOZ_RELEASE_ASSERT(aStart <= aEnd, "Overflow!");
  Rebind(aStart, uint32_t(aEnd - aStart));
}