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|
{- common functions for encryptable remotes
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Helper.Encryptable where
import qualified Data.Map as M
import Common.Annex
import Types.Remote
import Crypto
import qualified Annex
import Config
{- Encryption setup for a remote. The user must specify whether to use
- an encryption key, or not encrypt. An encrypted cipher is created, or is
- updated to be accessible to an additional encryption key. -}
encryptionSetup :: RemoteConfig -> Annex RemoteConfig
encryptionSetup c =
case (M.lookup "encryption" c, extractCipher c) of
(Nothing, Nothing) -> error "Specify encryption=key or encryption=none"
(Just "none", Nothing) -> return c
(Just "none", Just _) -> error "Cannot change encryption type of existing remote."
(Nothing, Just _) -> return c
(Just _, Nothing) -> use "encryption setup" $ genCipher c
(Just _, Just v) -> use "encryption updated" $ updateCipher c v
where
use m a = do
cipher <- liftIO a
showNote $ m ++ " " ++ describeCipher cipher
return $ M.delete "encryption" $ storeCipher c cipher
{- Modifies a Remote to support encryption.
-
- Two additional functions must be provided by the remote,
- to support storing and retrieving encrypted content. -}
encryptableRemote
:: Maybe RemoteConfig
-> ((Cipher, Key) -> Key -> Annex Bool)
-> ((Cipher, Key) -> FilePath -> Annex Bool)
-> Remote Annex
-> Remote Annex
encryptableRemote c storeKeyEncrypted retrieveKeyFileEncrypted r =
r {
storeKey = store,
retrieveKeyFile = retrieve,
removeKey = withkey $ removeKey r,
hasKey = withkey $ hasKey r,
cost = cost r + encryptedRemoteCostAdj
}
where
store k = cip k >>= maybe
(storeKey r k)
(`storeKeyEncrypted` k)
retrieve k f = cip k >>= maybe
(retrieveKeyFile r k f)
(`retrieveKeyFileEncrypted` f)
withkey a k = cip k >>= maybe (a k) (a . snd)
cip = cipherKey c
{- Gets encryption Cipher. The decrypted Cipher is cached in the Annex
- state. -}
remoteCipher :: RemoteConfig -> Annex (Maybe Cipher)
remoteCipher c = maybe expensive cached =<< Annex.getState Annex.cipher
where
cached cipher = return $ Just cipher
expensive = case extractCipher c of
Nothing -> return Nothing
Just encipher -> do
showNote "gpg"
cipher <- liftIO $ decryptCipher c encipher
Annex.changeState (\s -> s { Annex.cipher = Just cipher })
return $ Just cipher
{- Gets encryption Cipher, and encrypted version of Key. -}
cipherKey :: Maybe RemoteConfig -> Key -> Annex (Maybe (Cipher, Key))
cipherKey Nothing _ = return Nothing
cipherKey (Just c) k = remoteCipher c >>= maybe (return Nothing) encrypt
where
encrypt ciphertext = do
k' <- liftIO $ encryptKey ciphertext k
return $ Just (ciphertext, k')
|
