mfbt/SHA1.h
author Petru Lingurar <petru.lingurar@softvision.ro>
Fri, 21 Dec 2018 08:56:47 +0000
changeset 501492 65621d0fe1262af0643cec37c23b2d9ec42588ad
parent 215455 91d7659bb35145e10ff737753688e0972c1a79b5
child 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1513938 - Enforce a Bundle size limit and drop `privateSession` if exceeds it. r=JanH, a=jcristau The `privateSession` key would normally allow persisting the Private Browsing session across OOMs in Activity's Bundle. We need to do that to avoid storing private, sensible data on disk like we do with the normal browsing session. In some cases `privateSession` would contain a lot of data which, along with other possible concurrent transactions could overflow Binder's buffer which has a limited fixed size, currently 1Mb. To avoid this, we will drop `privateSession` from the Bundle if the resulting size is greater than a _speculative_ size of 300KBs which would mean that in the case of an OOM all Private Browsing state would be lost. Bug 1515592 is filed to investigate for a better solution. Differential Revision: https://phabricator.services.mozilla.com/D15067

/* -*- 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/. */

/* Simple class for computing SHA1. */

#ifndef mozilla_SHA1_h
#define mozilla_SHA1_h

#include "mozilla/Types.h"

#include <stddef.h>
#include <stdint.h>

namespace mozilla {

/**
 * This class computes the SHA1 hash of a byte sequence, or of the concatenation
 * of multiple sequences.  For example, computing the SHA1 of two sequences of
 * bytes could be done as follows:
 *
 *   void SHA1(const uint8_t* buf1, uint32_t size1,
 *             const uint8_t* buf2, uint32_t size2,
 *             SHA1Sum::Hash& hash)
 *   {
 *     SHA1Sum s;
 *     s.update(buf1, size1);
 *     s.update(buf2, size2);
 *     s.finish(hash);
 *   }
 *
 * The finish method may only be called once and cannot be followed by calls
 * to update.
 */
class SHA1Sum
{
  union
  {
    uint32_t mW[16]; /* input buffer */
    uint8_t mB[64];
  } mU;
  uint64_t mSize; /* count of hashed bytes. */
  unsigned mH[22]; /* 5 state variables, 16 tmp values, 1 extra */
  bool mDone;

public:
  MFBT_API SHA1Sum();

  static const size_t kHashSize = 20;
  typedef uint8_t Hash[kHashSize];

  /* Add len bytes of dataIn to the data sequence being hashed. */
  MFBT_API void update(const void* aData, uint32_t aLength);

  /* Compute the final hash of all data into hashOut. */
  MFBT_API void finish(SHA1Sum::Hash& aHashOut);
};

} /* namespace mozilla */

#endif /* mozilla_SHA1_h */