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