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|
{- git-annex crypto
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Crypto (
genCipher,
updateCipher,
storeCipher,
extractCipher,
decryptCipher,
encryptKey,
encryptContent,
decryptContent
) where
import qualified Data.ByteString.Lazy.Char8 as L
import qualified Data.Map as M
import System.IO
import System.Cmd.Utils
import Types
import RemoteClass
import Utility
data Cipher = Cipher String -- XXX ideally, this would be a locked memory region
data EncryptedCipher = EncryptedCipher String
deriving Show
{- Creates a new Cipher, encrypted as specified in the remote's configuration -}
genCipher :: RemoteConfig -> IO EncryptedCipher
genCipher config = do
random <- genrandom
encryptCipher config $ Cipher random
where
genrandom = gpgPipeRead
[ Params "--armor --gen-random"
, Param $ show randomquality
, Param $ show ciphersize
]
randomquality = 1 -- 1 is /dev/urandom; 2 is /dev/random
ciphersize = 1024
{- Updates an existing Cipher, re-encrypting it as specified in the
- remote's configuration -}
updateCipher :: RemoteConfig -> EncryptedCipher -> IO EncryptedCipher
updateCipher config encipher = do
cipher <- decryptCipher config encipher
encryptCipher config cipher
{- Stores an EncryptedCipher in a remote's configuration. -}
storeCipher :: RemoteConfig -> EncryptedCipher -> RemoteConfig
storeCipher config (EncryptedCipher c) = M.insert "cipher" c config
{- Extracts an EncryptedCipher from a remote's configuration. -}
extractCipher :: RemoteConfig -> EncryptedCipher
extractCipher config = case M.lookup "cipher" config of
Just c -> EncryptedCipher c
Nothing -> error "missing cipher in remote config"
{- Encryptes a Cipher as specified by a remote's configuration. -}
encryptCipher :: RemoteConfig -> Cipher -> IO EncryptedCipher
encryptCipher config (Cipher c) = do
encipher <- gpgPipeBoth (encrypt++recipient) c
return $ EncryptedCipher encipher
where
encrypt =
[ Params "--encrypt --armor"
, Params "--trust-model always"
]
recipient = case M.lookup "encryption" config of
Nothing -> [ Param "--default-recipient-self" ]
Just r ->
-- Force gpg to only encrypt to the specified
-- recipients, not configured defaults.
[ Params "--no-encrypt-to --no-default-recipient"
, Param "--recipient"
, Param r
]
{- Decrypting an EncryptedCipher is expensive; the Cipher should be cached. -}
decryptCipher :: RemoteConfig -> EncryptedCipher -> IO Cipher
decryptCipher = error "TODO"
{- Genetates an encrypted form of a Key. The enctyption does not need to be
- reversable, nor does it need to be the same type of encryption used
- on content. -}
encryptKey :: Cipher -> Key -> IO Key
encryptKey = error "TODO"
{- Streams content, encrypting. -}
encryptContent :: Cipher -> L.ByteString -> IO L.ByteString
encryptContent = error "TODO"
{- Streams encrypted content, decrypting. -}
decryptContent :: Cipher -> L.ByteString -> IO L.ByteString
decryptContent = error "TODO"
gpgParams :: [CommandParam] -> [String]
gpgParams params = ["--batch", "--quiet"] ++ toCommand params
gpgPipeRead :: [CommandParam] -> IO String
gpgPipeRead params = pOpen ReadFromPipe "gpg" (gpgParams params) hGetContentsStrict
gpgPipeBoth :: [CommandParam] -> String -> IO String
gpgPipeBoth params input = do
(_, s) <- pipeBoth "gpg" (gpgParams params) input
return s
|
