git-annex/Types/Crypto.hs
Joey Hess 7c1a9cdeb9 partially complete gcrypt remote (local send done; rest not)
This is a git-remote-gcrypt encrypted special remote. Only sending files
in to the remote works, and only for local repositories.

Most of the work so far has involved making initremote work. A particular
problem is that remote setup in this case needs to generate its own uuid,
derivied from the gcrypt-id. That required some larger changes in the code
to support.

For ssh remotes, this will probably just reuse Remote.Rsync's code, so
should be easy enough. And for downloading from a web remote, I will need
to factor out the part of Remote.Git that does that.

One particular thing that will need work is supporting hot-swapping a local
gcrypt remote. I think it needs to store the gcrypt-id in the git config of the
local remote, so that it can check it every time, and compare with the
cached annex-uuid for the remote. If there is a mismatch, it can change
both the cached annex-uuid and the gcrypt-id. That should work, and I laid
some groundwork for it by already reading the remote's config when it's
local. (Also needed for other reasons.)

This commit was sponsored by Daniel Callahan.
2013-09-07 18:38:00 -04:00

73 lines
1.9 KiB
Haskell

{- git-annex crypto types
-
- Copyright 2011-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Types.Crypto (
Cipher(..),
StorableCipher(..),
EncryptedCipherVariant(..),
KeyIds(..),
Mac(..),
readMac,
showMac,
defaultMac,
calcMac,
) where
import qualified Data.ByteString.Lazy as L
import Data.Digest.Pure.SHA
import Utility.Gpg (KeyIds(..))
-- XXX ideally, this would be a locked memory region
data Cipher = Cipher String | MacOnlyCipher String
data StorableCipher = EncryptedCipher String EncryptedCipherVariant KeyIds
| SharedCipher String
deriving (Ord, Eq)
data EncryptedCipherVariant = Hybrid | PubKey
deriving (Ord, Eq)
{- File names are (client-side) MAC'ed on special remotes.
- The chosen MAC algorithm needs to be same for all files stored on the
- remote.
-}
data Mac = HmacSha1 | HmacSha224 | HmacSha256 | HmacSha384 | HmacSha512
deriving (Eq)
defaultMac :: Mac
defaultMac = HmacSha1
-- MAC algorithms are shown as follows in the file names.
showMac :: Mac -> String
showMac HmacSha1 = "HMACSHA1"
showMac HmacSha224 = "HMACSHA224"
showMac HmacSha256 = "HMACSHA256"
showMac HmacSha384 = "HMACSHA384"
showMac HmacSha512 = "HMACSHA512"
-- Read the MAC algorithm from the remote config.
readMac :: String -> Maybe Mac
readMac "HMACSHA1" = Just HmacSha1
readMac "HMACSHA224" = Just HmacSha224
readMac "HMACSHA256" = Just HmacSha256
readMac "HMACSHA384" = Just HmacSha384
readMac "HMACSHA512" = Just HmacSha512
readMac _ = Nothing
calcMac
:: Mac -- ^ MAC
-> L.ByteString -- ^ secret key
-> L.ByteString -- ^ message
-> String -- ^ MAC'ed message, in hexadecimals
calcMac mac = case mac of
HmacSha1 -> showDigest $* hmacSha1
HmacSha224 -> showDigest $* hmacSha224
HmacSha256 -> showDigest $* hmacSha256
HmacSha384 -> showDigest $* hmacSha384
HmacSha512 -> showDigest $* hmacSha512
where
($*) g f x y = g $ f x y