[Sync] Add SyncEncryptionHandler

sync/internal_api/sync_encryption_handler_impl.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SYNC_INTERNAL_API_SYNC_ENCRYPTION_HANDLER_IMPL_H_
+#define SYNC_INTERNAL_API_SYNC_ENCRYPTION_HANDLER_IMPL_H_
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "sync/internal_api/public/sync_encryption_handler.h"
+#include "sync/syncable/nigori_handler.h"
+
+namespace syncer {
+
+struct UserShare;
+class WriteNode;
+class WriteTransaction;
+
+// TODO(zea): Make this class explicitly non-thread safe and ensure its only
+// accessed from the sync thread, with the possible exception of
+// GetEncryptedTypes. Need to cache explicit passphrase state on the UI thread.

[tim (not reviewing), 2012/08/14 02:32:20]

I think it would be useful to have a class comment / ascii art showing the
typical lifetime of this class is, what happens at startup, the fact that all
changes (from the user side and from the sync side) go through this gauntlet,
and which events trigger which functions. 

[Nicolas Zea, 2012/08/14 23:24:51]

Done.

+class SyncEncryptionHandlerImpl
+    : public SyncEncryptionHandler,
+      public syncable::NigoriHandler {
+ public:
+  SyncEncryptionHandlerImpl(UserShare* user_share,
+                            Cryptographer* cryptographer);
+  virtual ~SyncEncryptionHandlerImpl();
+
+  // SyncEncryptionHandler implementation.
+  virtual void AddObserver(Observer* observer) OVERRIDE;
+  virtual void RemoveObserver(Observer* observer) OVERRIDE;
+  virtual void ReloadNigori() OVERRIDE;
+  virtual void SetEncryptionPassphrase(const std::string& passphrase,
+                                       bool is_explicit) OVERRIDE;
+  virtual void SetDecryptionPassphrase(const std::string& passphrase) OVERRIDE;
+  virtual void EnableEncryptEverything() OVERRIDE;
+  virtual bool EncryptEverythingEnabled() const OVERRIDE;
+  virtual bool IsUsingExplicitPassphrase() const OVERRIDE;
+
+  // NigoriHandler implementation.
+  // Note: all methods are invoked while the caller holds a transaction.
+  virtual void UpdateFromNigori(
+      const sync_pb::NigoriSpecifics& nigori) OVERRIDE;
+  virtual void UpdateNigoriFromEncryptedTypes(
+       sync_pb::NigoriSpecifics* nigori) const OVERRIDE;
+  virtual ModelTypeSet GetEncryptedTypes() const OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SyncEncryptionHandlerImpl);

[tim (not reviewing), 2012/08/14 02:32:20]

nit - put this at the bottom.

[Nicolas Zea, 2012/08/14 23:24:51]

Done.

+  FRIEND_TEST_ALL_PREFIXES(SyncEncryptionHandlerImplTest,
+                           NigoriEncryptionTypes);
+  FRIEND_TEST_ALL_PREFIXES(SyncEncryptionHandlerImplTest,
+                           EncryptEverythingExplicit);
+  FRIEND_TEST_ALL_PREFIXES(SyncEncryptionHandlerImplTest,
+                           EncryptEverythingImplicit);
+  FRIEND_TEST_ALL_PREFIXES(SyncEncryptionHandlerImplTest,
+                           UnknownSensitiveTypes);
+
+  // Iterate over all encrypted types ensuring each entry is properly encrypted.
+  void ReEncryptEverything(WriteTransaction* trans);
+
+  // Apply a nigori update. Updates internal and cryptographer state.
+  // Returns true on success, false if |nigori| was incompatible, and the
+  // nigori node must be corrected.
+  // Note: must be called from within a transaction.
+  bool ApplyNigoriUpdate(const sync_pb::NigoriSpecifics& nigori,
+                         Cryptographer* cryptographer);
+
+  // Wrapper around WriteEncryptionStateToNigori that creates a new write
+  // transaction.
+  void RewriteNigori();
+
+  // Write the current encryption state into the nigori node. This includes
+  // the encrypted types/encrypt everything state, as well as the keybag/
+  // explicit passphrase state (if the cryptographer is ready).
+  void WriteEncryptionStateToNigori(WriteTransaction* trans);
+
+  // Updates local encrypted types from |nigori|.
+  // Returns true if the local set of encrypted types either matched or was
+  // a subset of that in |nigori|. Returns false if the local state already
+  // had stricter encryption than |nigori|, and the nigori node needs to be
+  // updated with the newer encryption state.
+  // Note: must be called from within a transaction.
+  bool UpdateEncryptedTypesFromNigori(const sync_pb::NigoriSpecifics& nigori);
+
+  // The final step of SetEncryptionPassphrase and SetDecryptionPassphrase that
+  // notifies observers of the result of the set passphrase operation, updates
+  // the nigori node, and does re-encryption.
+  // |success|: true if the operation was successful and false otherwise. If
+  //            success == false, we send an OnPassphraseRequired notification.
+  // |bootstrap_token|: used to inform observers if the cryptographer's
+  //                    bootstrap token was updated.
+  // |is_explicit|: used to differentiate between a custom passphrase (true) and
+  //                a GAIA passphrase that is implicitly used for encryption
+  //                (false).
+  // |trans| and |nigori_node|: used to access data in the cryptographer.
+  void FinishSetPassphrase(bool success,
+                           const std::string& bootstrap_token,
+                           bool is_explicit,
+                           WriteTransaction* trans,
+                           WriteNode* nigori_node);
+
+  // Merges the given set of encrypted types with the existing set and emits a
+  // notification if necessary.
+  // Note: must be called from within a transaction.
+  void MergeEncryptedTypes(ModelTypeSet encrypted_types);
+
+  base::WeakPtrFactory<SyncEncryptionHandlerImpl> weak_ptr_factory_;
+
+  ObserverList<SyncEncryptionHandler::Observer> observers_;
+
+  // The current user share (for creating transactions).
+  UserShare* user_share_;
+
+  // TODO(zea): have the sync encryption handler own the cryptographer, and live
+  // in the directory.
+  Cryptographer* cryptographer_;
+
+  // The set of types that require encryption. This is accessed on all sync
+  // datatype threads when we write to a node, so we must hold a transaction
+  // whenever we touch/read it.
+  ModelTypeSet encrypted_types_;
+
+  // Sync encryption state. These are only modified and accessed from the sync
+  // thread.
+  bool encrypt_everything_;
+  bool explicit_passphrase_;
+
+  // The number of times we've automatically (i.e. not via SetPassphrase or
+  // conflict resolver) updated the nigori's encryption keys in this chrome
+  // instantiation.
+  int nigori_overwrite_count_;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_IMPL_H_