| // Copyright 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> |
| |
| #include "base/gtest_prod_util.h" |
| #include "base/memory/linked_ptr.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "sync/base/sync_export.h" |
| #include "sync/protocol/encryption.pb.h" |
| #include "sync/util/nigori.h" |
| |
| namespace sync_pb { |
| class NigoriKeyBag; |
| class NigoriSpecifics; |
| } |
| |
| namespace syncer { |
| |
| class Encryptor; |
| |
| SYNC_EXPORT_PRIVATE extern const char kNigoriTag[]; |
| |
| // The parameters used to initialize a Nigori instance. |
| struct KeyParams { |
| std::string hostname; |
| std::string username; |
| std::string password; |
| }; |
| |
| // This class manages the Nigori objects used to encrypt and decrypt sensitive |
| // sync data (eg. passwords). Each Nigori object knows how to handle data |
| // protected with a particular passphrase. |
| // |
| // Whenever an update to the Nigori sync node is received from the server, |
| // SetPendingKeys should be called with the encrypted contents of that node. |
| // Most likely, an updated Nigori node means that a new passphrase has been set |
| // and that future node updates won't be decryptable. To remedy this, the user |
| // should be prompted for the new passphrase and DecryptPendingKeys be called. |
| // |
| // Whenever a update to an encrypted node is received from the server, |
| // CanDecrypt should be used to verify whether the Cryptographer can decrypt |
| // that node. If it cannot, then the application of that update should be |
| // delayed until after it can be decrypted. |
| class SYNC_EXPORT Cryptographer { |
| public: |
| // Does not take ownership of |encryptor|. |
| explicit Cryptographer(Encryptor* encryptor); |
| explicit Cryptographer(const Cryptographer& other); |
| ~Cryptographer(); |
| |
| // |restored_bootstrap_token| can be provided via this method to bootstrap |
| // 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); |
| |
| // 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 |
| // |encrypted| was encrypted with the current default key. This avoids |
| // unnecessarily modifying |encrypted| if the change had no practical effect. |
| // Returns true unless encryption fails or |message| isn't valid (e.g. a |
| // required field isn't set). |
| bool Encrypt(const ::google::protobuf::MessageLite& message, |
| sync_pb::EncryptedData* encrypted) const; |
| |
| // Encrypted |serialized| into |encrypted|. Does not overwrite |encrypted| if |
| // |message| already matches the decrypted data within |encrypted| and |
| // |encrypted| was encrypted with the current default key. This avoids |
| // unnecessarily modifying |encrypted| if the change had no practical effect. |
| // Returns true unless encryption fails or |message| isn't valid (e.g. a |
| // required field isn't set). |
| bool EncryptString(const std::string& serialized, |
| sync_pb::EncryptedData* encrypted) const; |
| |
| // Decrypts |encrypted| into |message|. Returns true unless decryption fails, |
| // or |message| fails to parse the decrypted data. |
| bool Decrypt(const sync_pb::EncryptedData& encrypted, |
| ::google::protobuf::MessageLite* message) const; |
| |
| // Decrypts |encrypted| and returns plaintext decrypted data. If decryption |
| // fails, returns empty string. |
| std::string DecryptToString(const sync_pb::EncryptedData& encrypted) const; |
| |
| // Encrypts the set of currently known keys into |encrypted|. Returns true if |
| // successful. |
| bool GetKeys(sync_pb::EncryptedData* encrypted) const; |
| |
| // Creates a new Nigori instance using |params|. If successful, |params| will |
| // become the default encryption key and be used for all future calls to |
| // Encrypt. |
| // Will decrypt the pending keys and install them if possible (pending key |
| // will not overwrite default). |
| bool AddKey(const KeyParams& params); |
| |
| // Same as AddKey(..), but builds the new Nigori from a previously persisted |
| // bootstrap token. This can be useful when consuming a bootstrap token |
| // with a cryptographer that has already been initialized. |
| // Updates the default key. |
| // Will decrypt the pending keys and install them if possible (pending key |
| // will not overwrite default). |
| bool AddKeyFromBootstrapToken(const std::string restored_bootstrap_token); |
| |
| // Creates a new Nigori instance using |params|. If successful, |params| |
| // will be added to the nigori keybag, but will not be the default encryption |
| // key (default_nigori_ will remain the same). |
| // Prereq: is_initialized() must be true. |
| // Will decrypt the pending keys and install them if possible (pending key |
| // will become the new default). |
| bool AddNonDefaultKey(const KeyParams& params); |
| |
| // Decrypts |encrypted| and uses its contents to initialize Nigori instances. |
| // Returns true unless decryption of |encrypted| fails. The caller is |
| // responsible for checking that CanDecrypt(encrypted) == true. |
| // Does not modify the default key. |
| void InstallKeys(const sync_pb::EncryptedData& encrypted); |
| |
| // Makes a local copy of |encrypted| to later be decrypted by |
| // DecryptPendingKeys. This should only be used if CanDecrypt(encrypted) == |
| // false. |
| void SetPendingKeys(const sync_pb::EncryptedData& encrypted); |
| |
| // Makes |pending_keys_| available to callers that may want to cache its |
| // value for later use on the UI thread. It is illegal to call this if the |
| // cryptographer has no pending keys. Like other calls that access the |
| // cryptographer, this method must be called from within a transaction. |
| const sync_pb::EncryptedData& GetPendingKeys() const; |
| |
| // Attempts to decrypt the set of keys that was copied in the previous call to |
| // SetPendingKeys using |params|. Returns true if the pending keys were |
| // successfully decrypted and installed. If successful, the default key |
| // 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_name_.empty(); |
| } |
| |
| // Returns whether this Cryptographer is ready to encrypt and decrypt data. |
| bool is_ready() const { |
| return is_initialized() && !has_pending_keys(); |
| } |
| |
| // 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; |
| |
| Encryptor* encryptor() const { return encryptor_; } |
| |
| // Returns true if |keybag| is decryptable and either is a subset of nigoris_ |
| // and/or has a different default key. |
| bool KeybagIsStale(const sync_pb::EncryptedData& keybag) const; |
| |
| // Returns the name of the Nigori key currently used for encryption. |
| std::string GetDefaultNigoriKeyName() const; |
| |
| // Returns a serialized sync_pb::NigoriKey version of current default |
| // encryption key. |
| std::string GetDefaultNigoriKeyData() const; |
| |
| // Generates a new Nigori from |serialized_nigori_key|, and if successful |
| // installs the new nigori as the default key. |
| bool ImportNigoriKey(const std::string serialized_nigori_key); |
| |
| private: |
| 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 to the keybag, optionally making it the |
| // default as well. |
| bool AddKeyImpl(scoped_ptr<Nigori> nigori, bool set_as_default); |
| |
| // Helper to unencrypt a bootstrap token into a serialized sync_pb::NigoriKey. |
| std::string UnpackBootstrapToken(const std::string& token) const; |
| |
| Encryptor* const encryptor_; |
| |
| // The Nigoris we know about, mapped by key name. |
| NigoriMap nigoris_; |
| |
| // The key name associated with the default nigori. If non-empty, must |
| // correspond to a nigori within |nigoris_|. |
| std::string default_nigori_name_; |
| |
| scoped_ptr<sync_pb::EncryptedData> pending_keys_; |
| |
| DISALLOW_ASSIGN(Cryptographer); |
| }; |
| |
| } // namespace syncer |
| |
| #endif // SYNC_UTIL_CRYPTOGRAPHER_H_ |