git-annex/Annex/UUID.hs
Joey Hess b43c835def
instantiate remotes that are behind a proxy remote
Untested, but this should be close to working. The proxied remotes have
the same url but a different uuid. When talking to current
git-annex-shell, it will fail due to a uuid mismatch. Once it supports
proxies, it will know that the presented uuid is for a remote that it
proxies for.

The check for any git config settings for a remote with the same name as
the proxied remote is there for several reasons. One is security:
Writing a name to the proxy log should not cause changes to
how an existing, configured git remote operates in a different clone of
the repo.

It's possible that the user has been using a proxied remote, and decides
to set a git config for it. We can't tell the difference between that
scenario and an evil remote trying to eg, intercept a file upload
by replacing their remote with a proxied remote.

Also, if the user sets some git config, does it override the config
inherited from the proxy remote? Seems a difficult question. Luckily,
the above means we don't need to think through it.

This does mean though, that in order for a user to change the config of
a proxy remote, they have to manually set its annex-uuid and url, as
well as the config they want to change. They may also have to set any of
the inherited configs that they were relying on.
2024-06-06 17:15:32 -04:00

127 lines
3.3 KiB
Haskell

{- git-annex uuids
-
- Each git repository used by git-annex has an annex.uuid setting that
- uniquely identifies that repository.
-
- UUIDs of remotes are cached in git config, using keys named
- remote.<name>.annex-uuid
-
- Copyright 2010-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Annex.UUID (
configkeyUUID,
configRepoUUID,
getUUID,
getRepoUUID,
getUncachedUUID,
isUUIDConfigured,
prepUUID,
genUUID,
genUUIDInNameSpace,
gCryptNameSpace,
removeRepoUUID,
storeUUID,
storeUUIDIn,
setUUID,
webUUID,
bitTorrentUUID,
) where
import Annex.Common
import qualified Annex
import qualified Git
import qualified Git.Config
import Git.Types
import Config
import qualified Data.UUID as U
import qualified Data.UUID.V4 as U4
import qualified Data.UUID.V5 as U5
import qualified Data.ByteString as S
import Data.String
configkeyUUID :: ConfigKey
configkeyUUID = annexConfig "uuid"
configRepoUUID :: Git.Repo -> ConfigKey
configRepoUUID r = remoteAnnexConfig r "uuid"
{- Generates a random UUID, that does not include the MAC address. -}
genUUID :: IO UUID
genUUID = toUUID <$> U4.nextRandom
{- Generates a UUID from a given string, using a namespace.
- Given the same namespace, the same string will always result
- in the same UUID. -}
genUUIDInNameSpace :: U.UUID -> S.ByteString -> UUID
genUUIDInNameSpace namespace = toUUID . U5.generateNamed namespace . S.unpack
{- Namespace used for UUIDs derived from git-remote-gcrypt ids. -}
gCryptNameSpace :: U.UUID
gCryptNameSpace = U5.generateNamed U5.namespaceURL $
S.unpack "http://git-annex.branchable.com/design/gcrypt/"
{- Get current repository's UUID. -}
getUUID :: Annex UUID
getUUID = annexUUID <$> Annex.getGitConfig
{- Looks up a remote repo's UUID, caching it in .git/config if
- it's not already. -}
getRepoUUID :: Git.Repo -> Annex UUID
getRepoUUID r = do
c <- toUUID <$> getConfig cachekey ""
let u = getUncachedUUID r
if c /= u && u /= NoUUID
then do
updatecache u
return u
else return c
where
updatecache u = do
g <- gitRepo
when (g /= r) $ storeUUIDIn cachekey u
cachekey = configRepoUUID r
removeRepoUUID :: Annex ()
removeRepoUUID = do
unsetConfig configkeyUUID
storeUUID NoUUID
getUncachedUUID :: Git.Repo -> UUID
getUncachedUUID = toUUID . Git.Config.get configkeyUUID ""
-- Does the repo's config have a key for the UUID?
-- True even when the key has no value.
isUUIDConfigured :: Git.Repo -> Bool
isUUIDConfigured = isJust . Git.Config.getMaybe configkeyUUID
{- Make sure that the repo has an annex.uuid setting. -}
prepUUID :: Annex ()
prepUUID = whenM ((==) NoUUID <$> getUUID) $
storeUUID =<< liftIO genUUID
storeUUID :: UUID -> Annex ()
storeUUID = storeUUIDIn configkeyUUID
storeUUIDIn :: ConfigKey -> UUID -> Annex ()
storeUUIDIn configfield = setConfig configfield . fromUUID
{- Only sets the configkey in the Repo; does not change .git/config -}
setUUID :: Git.Repo -> UUID -> IO Git.Repo
setUUID r u = do
let s = encodeBS $ show configkeyUUID ++ "=" ++ fromUUID u
Git.Config.store s Git.Config.ConfigList r
-- Dummy uuid for the whole web. Do not alter.
webUUID :: UUID
webUUID = UUID (fromString "00000000-0000-0000-0000-000000000001")
-- Dummy uuid for bittorrent. Do not alter.
bitTorrentUUID :: UUID
bitTorrentUUID = UUID (fromString "00000000-0000-0000-0000-000000000002")