git-annex/Annex/Perms.hs
Joey Hess d48b00ebed Direct mode .git/annex/objects directories are no longer left writable
Because that allowed writing to symlinks of files that are not present,
which followed the link and put bad content in an object location.

fsck: Fix up .git/annex/object directory permissions.

This commit was sponsored by an anonymous bitcoin donor.
2013-11-15 14:52:03 -04:00

117 lines
3.5 KiB
Haskell

{- git-annex file permissions
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.Perms (
setAnnexPerm,
annexFileMode,
createAnnexDirectory,
noUmask,
createContentDir,
freezeContentDir,
thawContentDir,
modifyContent,
) where
import Common.Annex
import Utility.FileMode
import Git.SharedRepository
import qualified Annex
import Annex.Exception
import Config
import System.Posix.Types
withShared :: (SharedRepository -> Annex a) -> Annex a
withShared a = maybe startup a =<< Annex.getState Annex.shared
where
startup = do
shared <- fromRepo getSharedRepository
Annex.changeState $ \s -> s { Annex.shared = Just shared }
a shared
{- Sets appropriate file mode for a file or directory in the annex,
- other than the content files and content directory. Normally,
- use the default mode, but with core.sharedRepository set,
- allow the group to write, etc. -}
setAnnexPerm :: FilePath -> Annex ()
setAnnexPerm file = unlessM crippledFileSystem $
withShared $ liftIO . go
where
go GroupShared = groupWriteRead file
go AllShared = modifyFileMode file $ addModes $
[ ownerWriteMode, groupWriteMode ] ++ readModes
go _ = noop
{- Gets the appropriate mode to use for creating a file in the annex
- (other than content files, which are locked down more). -}
annexFileMode :: Annex FileMode
annexFileMode = withShared $ return . go
where
go GroupShared = sharedmode
go AllShared = combineModes (sharedmode:readModes)
go _ = stdFileMode
sharedmode = combineModes
[ ownerWriteMode, groupWriteMode
, ownerReadMode, groupReadMode
]
{- Creates a directory inside the gitAnnexDir, including any parent
- directories. Makes directories with appropriate permissions. -}
createAnnexDirectory :: FilePath -> Annex ()
createAnnexDirectory dir = traverse dir [] =<< top
where
top = parentDir <$> fromRepo gitAnnexDir
traverse d below stop
| d `equalFilePath` stop = done
| otherwise = ifM (liftIO $ doesDirectoryExist d)
( done
, traverse (parentDir d) (d:below) stop
)
where
done = forM_ below $ \p -> do
liftIO $ createDirectoryIfMissing True p
setAnnexPerm p
{- Blocks writing to the directory an annexed file is in, to prevent the
- file accidentially being deleted. However, if core.sharedRepository
- is set, this is not done, since the group must be allowed to delete the
- file.
-}
freezeContentDir :: FilePath -> Annex ()
freezeContentDir file = unlessM crippledFileSystem $
liftIO . go =<< fromRepo getSharedRepository
where
dir = parentDir file
go GroupShared = groupWriteRead dir
go AllShared = groupWriteRead dir
go _ = preventWrite dir
thawContentDir :: FilePath -> Annex ()
thawContentDir file = unlessM crippledFileSystem $
liftIO $ allowWrite $ parentDir file
{- Makes the directory tree to store an annexed file's content,
- with appropriate permissions on each level. -}
createContentDir :: FilePath -> Annex ()
createContentDir dest = do
unlessM (liftIO $ doesDirectoryExist dir) $
createAnnexDirectory dir
-- might have already existed with restricted perms
unlessM crippledFileSystem $
liftIO $ allowWrite dir
where
dir = parentDir dest
{- Creates the content directory for a file if it doesn't already exist,
- or thaws it if it does, then runs an action to modify the file, and
- finally, freezes the content directory. -}
modifyContent :: FilePath -> Annex a -> Annex a
modifyContent f a = do
createContentDir f -- also thaws it
v <- tryAnnex a
freezeContentDir f
either throwAnnex return v