[Sync] Move keystore key handling to SyncEncryptionHandlerImpl

sync/util/cryptographer.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_UTIL_CRYPTOGRAPHER_H_
 #define SYNC_UTIL_CRYPTOGRAPHER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 45 matching lines @@
   // Cryptographer instance into the ready state (is_ready will be true).
   // It must be a string that was previously built by the
   // GetSerializedBootstrapToken function.  It is possible that the token is no
   // longer valid (due to server key change), in which case the normal
   // decryption code paths will fail and the user will need to provide a new
   // passphrase.
   // It is an error to call this if is_ready() == true, though it is fair to
   // never call Bootstrap at all.
   void Bootstrap(const std::string& restored_bootstrap_token);
 
-  // Bootstrap the keystore key.
-  void BootstrapKeystoreKey(
-      const std::string& restored_keystore_bootstrap_token);
-
   // Returns whether we can decrypt |encrypted| using the keys we currently know
   // about.
   bool CanDecrypt(const sync_pb::EncryptedData& encrypted) const;
 
   // Returns whether |encrypted| can be decrypted using the default encryption
   // key.
   bool CanDecryptUsingDefaultKey(const sync_pb::EncryptedData& encrypted) const;
 
   // Encrypts |message| into |encrypted|. Does not overwrite |encrypted| if
   // |message| already matches the decrypted data within |encrypted| and
@@ skipping 51 matching lines @@
   // is updated.
   bool DecryptPendingKeys(const KeyParams& params);
 
   // Sets the default key to the nigori with name |key_name|. |key_name| must
   // correspond to a nigori that has already been installed into the keybag.
   void SetDefaultKey(const std::string& key_name);
 
   bool is_initialized() const { return !nigoris_.empty() && default_nigori_; }
 
   // Returns whether this Cryptographer is ready to encrypt and decrypt data.
-  bool is_ready() const { return is_initialized() &&
-                          has_pending_keys() == false; }
+  bool is_ready() const {
+    return is_initialized() &&
+           has_pending_keys() == false;
+  }
 
   // Returns whether there is a pending set of keys that needs to be decrypted.
   bool has_pending_keys() const { return NULL != pending_keys_.get(); }
 
   // Obtain a token that can be provided on construction to a future
   // Cryptographer instance to bootstrap itself.  Returns false if such a token
   // can't be created (i.e. if this Cryptograhper doesn't have valid keys).
   bool GetBootstrapToken(std::string* token) const;
 
-  // Obtain the bootstrap token based on the keystore encryption key.
-  bool GetKeystoreKeyBootstrapToken(std::string* token) const;
-
-  // Set the keystore-derived nigori from the provided key.
-  // Returns true if we succesfully create the keystore derived nigori from the
-  // provided key, false otherwise.
-  bool SetKeystoreKey(const std::string& keystore_key);
-
-  // Returns true if we currently have a keystore-derived nigori, false
-  // otherwise.
-  bool HasKeystoreKey() const;
-
   Encryptor* encryptor() const { return encryptor_; }
 
  private:
   FRIEND_TEST_ALL_PREFIXES(SyncCryptographerTest, PackUnpack);
 
   typedef std::map<std::string, linked_ptr<const Nigori> > NigoriMap;
 
   // Helper method to instantiate Nigori instances for each set of key
   // parameters in |bag|.
   // Does not update the default nigori.
   void InstallKeyBag(const sync_pb::NigoriKeyBag& bag);
 
-  // Helper method to add a nigori as either the new default nigori or the new
-  // keystore nigori.
-  bool AddKeyImpl(Nigori* nigori, bool is_keystore_key);
+  // Helper method to add a nigori as the default key.
+  bool AddKeyImpl(Nigori* nigori);
 
   // Functions to serialize + encrypt a Nigori object in an opaque format for
   // persistence by sync infrastructure.
   bool PackBootstrapToken(const Nigori* nigori, std::string* pack_into) const;
   Nigori* UnpackBootstrapToken(const std::string& token) const;
 
   Encryptor* const encryptor_;
 
   NigoriMap nigoris_;  // The Nigoris we know about, mapped by key name.
   NigoriMap::value_type* default_nigori_;  // The Nigori used for encryption.

[akalin, 2012/08/22 22:09:34]

it seems unsafe to me to have this as a pointer into the map.  Maybe unpack it
to default_nigori_name_ and default_nigori_?  Or at least make it into an
iterator.

[Nicolas Zea, 2012/08/22 22:48:59]

Hmm. I don't think an iterator would have any benefit, since it can still be
erased without you knowing, and there's no way to safely verify if the iterator
is still valid. I'd also rather not introduce unnecessary lookups, since it's
basically a bug for the default to get deleted without clearing this, and it's
better to crash than to encrypt with the wrong key.

So I guess the solution is to ensure a bug forces a crash, without risking
deref'ing an invalid pointer. How about having Nigori provide a weak ptr, and
keeping a weakptr here? WDYT?

-  NigoriMap::value_type* keystore_nigori_; // Nigori generated from keystore.
 
   scoped_ptr<sync_pb::EncryptedData> pending_keys_;
 
   DISALLOW_COPY_AND_ASSIGN(Cryptographer);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_UTIL_CRYPTOGRAPHER_H_