git-annex/Remote/Helper/Special.hs
Joey Hess 2f2701137d
incremental verification for retrieval from all export remotes
Only for export remotes so far, not export/import.

Sponsored-by: Dartmouth College's Datalad project
2022-05-09 13:49:33 -04:00

261 lines
8.8 KiB
Haskell

{- helpers for special remotes
-
- Copyright 2011-2021 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE OverloadedStrings #-}
module Remote.Helper.Special (
findSpecialRemotes,
gitConfigSpecialRemote,
mkRetrievalVerifiableKeysSecure,
Storer,
Retriever,
Remover,
CheckPresent,
ContentSource,
fileStorer,
byteStorer,
fileRetriever,
fileRetriever',
byteRetriever,
storeKeyDummy,
retrieveKeyFileDummy,
removeKeyDummy,
checkPresentDummy,
SpecialRemoteCfg(..),
specialRemoteCfg,
specialRemoteConfigParsers,
specialRemoteType,
specialRemote,
specialRemote',
lookupName,
module X
) where
import Annex.Common
import Annex.SpecialRemote.Config
import Types.StoreRetrieve
import Types.Remote
import Annex.Verify
import Annex.UUID
import Config
import Config.Cost
import Utility.Metered
import Remote.Helper.Chunked as X
import Remote.Helper.Encryptable as X
import Annex.Content
import Messages.Progress
import qualified Git
import qualified Git.Construct
import Git.Types
import qualified Data.ByteString as S
import qualified Data.ByteString.Lazy as L
import qualified Data.Map as M
{- Special remotes don't have a configured url, so Git.Repo does not
- automatically generate remotes for them. This looks for a different
- configuration key instead.
-}
findSpecialRemotes :: String -> Annex [Git.Repo]
findSpecialRemotes s = do
m <- fromRepo Git.config
liftIO $ catMaybes <$> mapM construct (remotepairs m)
where
remotepairs = M.toList . M.filterWithKey match
construct (k,_) = Git.Construct.remoteNamedFromKey k
(pure Git.Construct.fromUnknown)
match (ConfigKey k) _ =
"remote." `S.isPrefixOf` k
&& (".annex-" <> encodeBS s) `S.isSuffixOf` k
{- Sets up configuration for a special remote in .git/config. -}
gitConfigSpecialRemote :: UUID -> RemoteConfig -> [(String, String)] -> Annex ()
gitConfigSpecialRemote u c cfgs = do
forM_ cfgs $ \(k, v) ->
setConfig (remoteAnnexConfig c (encodeBS k)) v
storeUUIDIn (remoteAnnexConfig c "uuid") u
-- RetrievalVerifiableKeysSecure unless overridden by git config.
--
-- Only looks at the RemoteGitConfig; the GitConfig's setting is
-- checked at the same place the RetrievalSecurityPolicy is checked.
mkRetrievalVerifiableKeysSecure :: RemoteGitConfig -> RetrievalSecurityPolicy
mkRetrievalVerifiableKeysSecure gc
| remoteAnnexAllowUnverifiedDownloads gc = RetrievalAllKeysSecure
| otherwise = RetrievalVerifiableKeysSecure
-- A Storer that expects to be provided with a file containing
-- the content of the key to store.
fileStorer :: (Key -> FilePath -> MeterUpdate -> Annex ()) -> Storer
fileStorer a k (FileContent f) m = a k f m
fileStorer a k (ByteContent b) m = withTmp k $ \f -> do
let f' = fromRawFilePath f
liftIO $ L.writeFile f' b
a k f' m
-- A Storer that expects to be provided with a L.ByteString of
-- the content to store.
byteStorer :: (Key -> L.ByteString -> MeterUpdate -> Annex ()) -> Storer
byteStorer a k c m = withBytes c $ \b -> a k b m
-- A Retriever that generates a lazy ByteString containing the Key's
-- content, and passes it to a callback action which will fully consume it
-- before returning.
byteRetriever :: (Key -> (L.ByteString -> Annex a) -> Annex a) -> Key -> MeterUpdate -> Maybe IncrementalVerifier -> (ContentSource -> Annex a) -> Annex a
byteRetriever a k _m _miv callback = a k (callback . ByteContent)
-- A Retriever that writes the content of a Key to a provided file.
-- The action is responsible for updating the progress meter as it
-- retrieves data. The incremental verifier is updated in the background as
-- the action writes to the file, but may not be updated with the entire
-- content of the file.
fileRetriever :: (RawFilePath -> Key -> MeterUpdate -> Annex ()) -> Retriever
fileRetriever a = fileRetriever' $ \f k m miv ->
let retrieve = a f k m
in tailVerify miv f retrieve
{- A Retriever that writes the content of a Key to a provided file.
- The action is responsible for updating the progress meter and the
- incremental verifier as it retrieves data.
-}
fileRetriever' :: (RawFilePath -> Key -> MeterUpdate -> Maybe IncrementalVerifier -> Annex ()) -> Retriever
fileRetriever' a k m miv callback = do
f <- prepTmp k
a f k m miv
pruneTmpWorkDirBefore f (callback . FileContent . fromRawFilePath)
{- The base Remote that is provided to specialRemote needs to have
- storeKey, retrieveKeyFile, removeKey, and checkPresent methods,
- but they are never actually used (since specialRemote replaces them).
- Here are some dummy ones.
-}
storeKeyDummy :: Key -> AssociatedFile -> MeterUpdate -> Annex ()
storeKeyDummy _ _ _ = error "missing storeKey implementation"
retrieveKeyFileDummy :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> VerifyConfig -> Annex Verification
retrieveKeyFileDummy _ _ _ _ _ = error "missing retrieveKeyFile implementation"
removeKeyDummy :: Key -> Annex ()
removeKeyDummy _ = error "missing removeKey implementation"
checkPresentDummy :: Key -> Annex Bool
checkPresentDummy _ = error "missing checkPresent implementation"
type RemoteModifier
= ParsedRemoteConfig
-> Storer
-> Retriever
-> Remover
-> CheckPresent
-> Remote
-> Remote
data SpecialRemoteCfg = SpecialRemoteCfg
{ chunkConfig :: ChunkConfig
, displayProgress :: Bool
}
specialRemoteCfg :: ParsedRemoteConfig -> SpecialRemoteCfg
specialRemoteCfg c = SpecialRemoteCfg (getChunkConfig c) True
-- Modifies a base RemoteType to support chunking and encryption configs.
specialRemoteType :: RemoteType -> RemoteType
specialRemoteType r = r
{ configParser = \c -> addRemoteConfigParser specialRemoteConfigParsers
<$> configParser r c
}
specialRemoteConfigParsers :: [RemoteConfigFieldParser]
specialRemoteConfigParsers = chunkConfigParsers ++ encryptionConfigParsers
-- Modifies a base Remote to support both chunking and encryption,
-- which special remotes typically should support.
--
-- Handles progress displays when displayProgress is set.
specialRemote :: RemoteModifier
specialRemote c = specialRemote' (specialRemoteCfg c) c
specialRemote' :: SpecialRemoteCfg -> RemoteModifier
specialRemote' cfg c storer retriever remover checkpresent baser = encr
where
encr = baser
{ storeKey = \k _f p -> cip >>= storeKeyGen k p
, retrieveKeyFile = \k _f d p vc -> cip >>= retrieveKeyFileGen k d p vc
, retrieveKeyFileCheap = case retrieveKeyFileCheap baser of
Nothing -> Nothing
Just a
-- retrieval of encrypted keys is never cheap
| isencrypted -> Nothing
| otherwise -> Just $ \k f d -> a k f d
-- When encryption is used, the remote could provide
-- some other content encrypted by the user, and trick
-- git-annex into decrypting it, leaking the decryption
-- into the git-annex repository. Verifiable keys
-- are the main protection against this attack.
, retrievalSecurityPolicy = if isencrypted
then mkRetrievalVerifiableKeysSecure (gitconfig baser)
else retrievalSecurityPolicy baser
, removeKey = \k -> cip >>= removeKeyGen k
, checkPresent = \k -> cip >>= checkPresentGen k
, cost = if isencrypted
then cost baser + encryptedRemoteCostAdj
else cost baser
, getInfo = do
l <- getInfo baser
return $ l ++
[ ("encryption", describeEncryption c)
, ("chunking", describeChunkConfig (chunkConfig cfg))
]
, whereisKey = if noChunks (chunkConfig cfg) && not isencrypted
then whereisKey baser
else Nothing
, exportActions = (exportActions baser)
{ storeExport = \f k l p -> displayprogress p k (Just f) $
storeExport (exportActions baser) f k l
, retrieveExport = \k l f p -> displayprogress p k Nothing $
retrieveExport (exportActions baser) k l f
}
}
cip = cipherKey c (gitconfig baser)
isencrypted = isEncrypted c
-- chunk, then encrypt, then feed to the storer
storeKeyGen k p enc = sendAnnex k rollback $ \src ->
displayprogress p k (Just src) $ \p' ->
storeChunks (uuid baser) chunkconfig enck k src p'
enc encr storer checkpresent
where
rollback = void $ removeKey encr k
enck = maybe id snd enc
-- call retriever to get chunks; decrypt them; stream to dest file
retrieveKeyFileGen k dest p vc enc =
displayprogress p k Nothing $ \p' ->
retrieveChunks retriever (uuid baser) vc
chunkconfig enck k dest p' enc encr
where
enck = maybe id snd enc
removeKeyGen k enc =
removeChunks remover (uuid baser) chunkconfig enck k
where
enck = maybe id snd enc
checkPresentGen k enc =
checkPresentChunks checkpresent (uuid baser) chunkconfig enck k
where
enck = maybe id snd enc
chunkconfig = chunkConfig cfg
displayprogress p k srcfile a
| displayProgress cfg = do
let bwlimit = remoteAnnexBwLimit (gitconfig baser)
metered (Just p) (KeySizer k (pure (fmap toRawFilePath srcfile))) bwlimit (const a)
| otherwise = a p
withBytes :: ContentSource -> (L.ByteString -> Annex a) -> Annex a
withBytes (ByteContent b) a = a b
withBytes (FileContent f) a = a =<< liftIO (L.readFile f)