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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.Encryptable where
import qualified Data.Map as M
import Control.Monad.State (liftIO)
import Types
import RemoteClass
import Crypto
import qualified Annex
import Messages
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 $ genCipher c
(Just _, Just v) -> use $ updateCipher c v
where
use a = do
cipher <- liftIO a
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 = do
v <- cipherKey c k
case v of
Nothing -> (storeKey r) k
Just x -> storeKeyEncrypted x k
retrieve k f = do
v <- cipherKey c k
case v of
Nothing -> (retrieveKeyFile r) k f
Just x -> retrieveKeyFileEncrypted x f
withkey a k = do
v <- cipherKey c k
case v of
Nothing -> a k
Just (_, k') -> a k'
{- Gets encryption Cipher, and encrypted version of Key.
-
- The decrypted Cipher is cached in the Annex state. -}
cipherKey :: Maybe RemoteConfig -> Key -> Annex (Maybe (Cipher, Key))
cipherKey Nothing _ = return Nothing
cipherKey (Just c) k = do
cache <- Annex.getState Annex.cipher
case cache of
Just cipher -> ret cipher
Nothing -> 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 })
ret cipher
where
ret cipher = do
k' <- liftIO $ encryptKey cipher k
return $ Just (cipher, k')
|
