1 files changed, 107 insertions, 0 deletions
diff --git a/dom/quota/EncryptingOutputStream.h b/dom/quota/EncryptingOutputStream.h
new file mode 100644
index 0000000000..9a23037731
--- /dev/null
+++ b/dom/quota/EncryptingOutputStream.h
@@ -0,0 +1,107 @@
+/* -*- 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
+
+// Local includes
+#include "EncryptedBlock.h"  // for EncryptedBlock
+
+// Global includes
+#include <cstddef>
+#include <cstdint>
+#include "ErrorList.h"
+#include "mozilla/InitializedOnce.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NotNull.h"
+#include "nsCOMPtr.h"
+#include "nsIOutputStream.h"
+#include "nsISupports.h"
+#include "nsTArray.h"
+#include "nscore.h"
+
+class nsIInputStream;
+class nsIRandomGenerator;
+
+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,
+                                  typename CipherStrategy::KeyType aKey);
+
+ private:
+  ~EncryptingOutputStream();
+
+  nsresult FlushToBaseStream();
+
+  bool EnsureBuffers();
+
+  CipherStrategy mCipherStrategy;
+
+  // 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;
+
+  nsCOMPtr<nsIRandomGenerator> mRandomGenerator;
+
+  // 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 StreamStatus() override;
+  NS_IMETHOD WriteSegments(nsReadSegmentFun aReader, void* aClosure,
+                           uint32_t aCount, uint32_t* _retval) override;
+};
+
+}  // namespace mozilla::dom::quota
+
+#endif