mfbt/HashFunctions.cpp
author Jed Davis <jld@mozilla.com>
Mon, 20 Nov 2017 10:47:54 -0700
changeset 447508 3b11a0bf7ae7a7fe0ed508583cf07441b68bab78
parent 214333 91d7659bb35145e10ff737753688e0972c1a79b5
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1409895 - Deny getcwd in the Linux content process sandbox. r=gcp getcwd won't do anything useful once we start chroot()ing to remove filesystem access; with this patch it will at least fail the same way regardless of whether user namespaces are available or if other factors prevent complete FS isolation. Bonus fix: improve the comments for this group of syscalls. MozReview-Commit-ID: KueZzly2mlO

/* -*- 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/. */

/* Implementations of hash functions. */

#include "mozilla/HashFunctions.h"
#include "mozilla/Types.h"

#include <string.h>

namespace mozilla {

uint32_t
HashBytes(const void* aBytes, size_t aLength)
{
  uint32_t hash = 0;
  const char* b = reinterpret_cast<const char*>(aBytes);

  /* Walk word by word. */
  size_t i = 0;
  for (; i < aLength - (aLength % sizeof(size_t)); i += sizeof(size_t)) {
    /* Do an explicitly unaligned load of the data. */
    size_t data;
    memcpy(&data, b + i, sizeof(size_t));

    hash = AddToHash(hash, data, sizeof(data));
  }

  /* Get the remaining bytes. */
  for (; i < aLength; i++) {
    hash = AddToHash(hash, b[i]);
  }
  return hash;
}

} /* namespace mozilla */