[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;
+
+// Sync encryption handler implementation.
+//
+// This class acts as the respository of all sync encryption state, and handles
+// encryption related changes/queries coming from both the chrome side and
+// the sync side (via NigoriHandler). It is capable of modifying all sync data
+// (re-encryption), updating the encrypted types, changing the encryption keys,
+// and creating/receiving nigori node updates.
+//
+// The class should live as long as the directory itself in order to ensure
+// any data read/written is properly decrypted/encrypted.
+//
+// Note: See sync_encryption_handler.h for a description of the chrome visible
+// methods and what they do, and nigori_handler.h for a description of the
+// sync methods.
+//
+// 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.
+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 Init() 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 ApplyNigoriUpdate(
+      const sync_pb::NigoriSpecifics& nigori,
+      syncable::BaseTransaction* const trans) OVERRIDE;
+  virtual void UpdateNigoriFromEncryptedTypes(
+      sync_pb::NigoriSpecifics* nigori,
+      syncable::BaseTransaction* const trans) const OVERRIDE;
+  virtual ModelTypeSet GetEncryptedTypes() const OVERRIDE;
+
+ private:
+  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 ApplyNigoriUpdateImpl(const sync_pb::NigoriSpecifics& nigori,
+                             syncable::BaseTransaction* const trans);
+
+  // 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_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncEncryptionHandlerImpl);
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_ENCRYPTION_HANDLER_IMPL_H_