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/* -*- 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/. */
#ifndef mozilla_dom_quota_EncryptingOutputStream_h
#define mozilla_dom_quota_EncryptingOutputStream_h
#include "mozilla/InitializedOnce.h"
#include "nsCOMPtr.h"
#include "nsIOutputStream.h"
#include "nsTArray.h"
#include "EncryptedBlock.h"
namespace mozilla::dom::quota {
class EncryptingOutputStreamBase : public nsIOutputStream {
public:
NS_DECL_THREADSAFE_ISUPPORTS
NS_IMETHOD Write(const char* aBuf, uint32_t aCount, uint32_t* _retval) final;
NS_IMETHOD WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
uint32_t* _retval) final;
NS_IMETHOD IsNonBlocking(bool* _retval) final;
protected:
EncryptingOutputStreamBase(nsCOMPtr<nsIOutputStream> aBaseStream,
size_t aBlockSize);
virtual ~EncryptingOutputStreamBase() = default;
nsresult WriteAll(const char* aBuf, uint32_t aCount,
uint32_t* aBytesWrittenOut);
InitializedOnce<const NotNull<nsCOMPtr<nsIOutputStream>>> mBaseStream;
const size_t mBlockSize;
};
// Wraps another nsIOutputStream using the CipherStrategy to encrypt it a
// page-based manner. Essentially, the CipherStrategy is not actually
// necessarily doing encryption, but any transformation to a page requiring some
// fixed-size reserved size per page.
//
// Paired with DecryptingInputStream which can be used to read the data written
// to the underlying stream, using the same (or more generally, a compatible)
// CipherStrategy, when created with the same key (assuming a symmetric cipher
// is being used; in principle, an asymmetric cipher would probably also work).
template <typename CipherStrategy>
class EncryptingOutputStream final : public EncryptingOutputStreamBase {
public:
// Construct a new blocking output stream to encrypt data to
// the given base stream. The base stream must also be blocking.
// The encryption block size may optionally be set to a value
// up to kMaxBlockSize.
explicit EncryptingOutputStream(nsCOMPtr<nsIOutputStream> aBaseStream,
size_t aBlockSize,
CipherStrategy aCipherStrategy,
typename CipherStrategy::KeyType aKey);
private:
~EncryptingOutputStream();
nsresult FlushToBaseStream();
bool EnsureBuffers();
const CipherStrategy mCipherStrategy;
const typename CipherStrategy::KeyType mKey;
// Buffer holding copied plain data. This must be copied here
// so that the encryption can be performed on a single flat buffer.
// XXX This is only necessary if the data written doesn't contain a portion of
// effective block size at a block boundary.
nsTArray<uint8_t> mBuffer;
// The next byte in the plain data to copy incoming data to.
size_t mNextByte = 0;
// Buffer holding the resulting encrypted data.
using EncryptedBlockType = EncryptedBlock<CipherStrategy::BlockPrefixLength,
CipherStrategy::BasicBlockSize>;
Maybe<EncryptedBlockType> mEncryptedBlock;
public:
NS_IMETHOD Close() override;
NS_IMETHOD Flush() override;
NS_IMETHOD WriteSegments(nsReadSegmentFun aReader, void* aClosure,
uint32_t aCount, uint32_t* _retval) override;
};
} // namespace mozilla::dom::quota
#endif