git-annex/Remote/BitTorrent.hs
Joey Hess eed20fe3b7
fix some file modes in calls to withTmpFileIn to honor umask
Also audited for other calls to openTempFile, and all are ok,
except for viaTmp which will need further work.

Remote.Directory fixed to set umask mode when writing to an export,
although it has another one using viaTmp that's not fixed.
Will make exports that are published via a http server running as
another user work, for example.

Remote.BitTorrent fixed to set umask mode when downloading the torrent
file. Normally this does not matter as that file does not hang around
after the download, but if a bittorrent download were started by one user,
got interrupted and then another user ran it, this will let them access
the torrent file created by the first user.
2020-09-02 14:36:08 -04:00

403 lines
12 KiB
Haskell

{- BitTorrent remote.
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Remote.BitTorrent (remote) where
import Annex.Common
import Types.Remote
import qualified Annex
import qualified Git
import qualified Git.Construct
import Config
import Config.Cost
import Logs.Web
import Types.UrlContents
import Types.CleanupActions
import Messages.Progress
import Utility.Metered
import Utility.Tmp
import Backend.URL
import Annex.Perms
import Annex.Tmp
import Annex.UUID
import qualified Annex.Url as Url
import Remote.Helper.ExportImport
import Annex.SpecialRemote.Config
import Network.URI
#ifdef WITH_TORRENTPARSER
import Data.Torrent
import qualified Data.ByteString.Lazy as B
#endif
remote :: RemoteType
remote = RemoteType
{ typename = "bittorrent"
, enumerate = list
, generate = gen
, configParser = mkRemoteConfigParser []
, setup = error "not supported"
, exportSupported = exportUnsupported
, importSupported = importUnsupported
}
-- There is only one bittorrent remote, and it always exists.
list :: Bool -> Annex [Git.Repo]
list _autoinit = do
r <- liftIO $ Git.Construct.remoteNamed "bittorrent" (pure Git.Construct.fromUnknown)
return [r]
gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> RemoteStateHandle -> Annex (Maybe Remote)
gen r _ rc gc rs = do
cst <- remoteCost gc expensiveRemoteCost
c <- parsedRemoteConfig remote rc
return $ Just Remote
{ uuid = bitTorrentUUID
, cost = cst
, name = Git.repoDescribe r
, storeKey = uploadKey
, retrieveKeyFile = downloadKey
, retrieveKeyFileCheap = Nothing
-- Bittorrent does its own hash checks.
, retrievalSecurityPolicy = RetrievalAllKeysSecure
, removeKey = dropKey
, lockContent = Nothing
, checkPresent = checkKey
, checkPresentCheap = False
, exportActions = exportUnsupported
, importActions = importUnsupported
, whereisKey = Nothing
, remoteFsck = Nothing
, repairRepo = Nothing
, config = c
, gitconfig = gc
, localpath = Nothing
, getRepo = return r
, readonly = True
, appendonly = False
, availability = GloballyAvailable
, remotetype = remote
, mkUnavailable = return Nothing
, getInfo = return []
, claimUrl = Just (pure . isSupportedUrl)
, checkUrl = Just checkTorrentUrl
, remoteStateHandle = rs
}
downloadKey :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Verification
downloadKey key _file dest p = do
get . map (torrentUrlNum . fst . getDownloader) =<< getBitTorrentUrls key
return UnVerified
where
get [] = giveup "could not download torrent"
get urls = do
showOutput -- make way for download progress bar
ok <- untilTrue urls $ \(u, filenum) -> do
registerTorrentCleanup u
checkDependencies
ifM (downloadTorrentFile u)
( downloadTorrentContent key u dest filenum p
, return False
)
unless ok $
get []
uploadKey :: Key -> AssociatedFile -> MeterUpdate -> Annex ()
uploadKey _ _ _ = giveup "upload to bittorrent not supported"
dropKey :: Key -> Annex ()
dropKey k = mapM_ (setUrlMissing k) =<< getBitTorrentUrls k
{- We punt and don't try to check if a torrent has enough seeders
- with all the pieces etc. That would be quite hard.. and even if
- implemented, it tells us nothing about the later state of the torrent.
-}
checkKey :: Key -> Annex Bool
checkKey = giveup "cannot reliably check torrent status"
getBitTorrentUrls :: Key -> Annex [URLString]
getBitTorrentUrls key = filter supported <$> getUrls key
where
supported u =
let (u', dl) = (getDownloader u)
in dl == OtherDownloader && isSupportedUrl u'
isSupportedUrl :: URLString -> Bool
isSupportedUrl u = isTorrentMagnetUrl u || isTorrentUrl u
isTorrentUrl :: URLString -> Bool
isTorrentUrl = maybe False (\u -> ".torrent" `isSuffixOf` uriPath u) . parseURI
isTorrentMagnetUrl :: URLString -> Bool
isTorrentMagnetUrl u = "magnet:" `isPrefixOf` u && checkbt (parseURI u)
where
checkbt (Just uri) | "xt=urn:btih:" `isInfixOf` uriQuery uri = True
checkbt _ = False
checkTorrentUrl :: URLString -> Annex UrlContents
checkTorrentUrl u = do
checkDependencies
registerTorrentCleanup u
ifM (downloadTorrentFile u)
( torrentContents u
, giveup "could not download torrent file"
)
{- To specify which file inside a multi-url torrent, the file number is
- appended to the url. -}
torrentUrlWithNum :: URLString -> Int -> URLString
torrentUrlWithNum u n = u ++ "#" ++ show n
torrentUrlNum :: URLString -> (URLString, Int)
torrentUrlNum u
| '#' `elem` u =
let (n, ru) = separate (== '#') (reverse u)
in (reverse ru, fromMaybe 1 $ readish $ reverse n)
| otherwise = (u, 1)
{- A Key corresponding to the URL of a torrent file. -}
torrentUrlKey :: URLString -> Annex Key
torrentUrlKey u = return $ fromUrl (fst $ torrentUrlNum u) Nothing
{- Temporary filename to use to store the torrent file. -}
tmpTorrentFile :: URLString -> Annex FilePath
tmpTorrentFile u = fromRepo . gitAnnexTmpObjectLocation =<< torrentUrlKey u
{- A cleanup action is registered to delete the torrent file
- when git-annex exits.
-
- This allows multiple actions that use the same torrent file
- directory to run in a single git-annex run, and only download the
- torrent file once.
-}
registerTorrentCleanup :: URLString -> Annex ()
registerTorrentCleanup u = Annex.addCleanup (TorrentCleanup u) $
liftIO . nukeFile =<< tmpTorrentFile u
{- Downloads the torrent file. (Not its contents.) -}
downloadTorrentFile :: URLString -> Annex Bool
downloadTorrentFile u = do
torrent <- tmpTorrentFile u
ifM (liftIO $ doesFileExist torrent)
( return True
, do
showAction "downloading torrent file"
createAnnexDirectory (parentDir torrent)
if isTorrentMagnetUrl u
then withOtherTmp $ \othertmp -> do
kf <- fromRawFilePath . keyFile <$> torrentUrlKey u
let metadir = othertmp </> "torrentmeta" </> kf
createAnnexDirectory metadir
showOutput
ok <- downloadMagnetLink u metadir torrent
liftIO $ removeDirectoryRecursive metadir
return ok
else withOtherTmp $ \othertmp -> do
withTmpFileIn othertmp "torrent" $ \f h -> do
liftIO $ hClose h
resetAnnexFilePerm f
ok <- Url.withUrlOptions $
Url.download nullMeterUpdate u f
when ok $
liftIO $ renameFile f torrent
return ok
)
downloadMagnetLink :: URLString -> FilePath -> FilePath -> Annex Bool
downloadMagnetLink u metadir dest = ifM download
( liftIO $ do
ts <- filter (".torrent" `isSuffixOf`)
<$> dirContents metadir
case ts of
(t:[]) -> do
renameFile t dest
return True
_ -> return False
, return False
)
where
download = runAria
[ Param "--bt-metadata-only"
, Param "--bt-save-metadata"
, Param u
, Param "--seed-time=0"
, Param "--summary-interval=0"
, Param "-d"
, File metadir
]
downloadTorrentContent :: Key -> URLString -> FilePath -> Int -> MeterUpdate -> Annex Bool
downloadTorrentContent k u dest filenum p = do
torrent <- tmpTorrentFile u
withOtherTmp $ \othertmp -> do
kf <- fromRawFilePath . keyFile <$> torrentUrlKey u
let downloaddir = othertmp </> "torrent" </> kf
createAnnexDirectory downloaddir
f <- wantedfile torrent
showOutput
ifM (download torrent downloaddir <&&> liftIO (doesFileExist (downloaddir </> f)))
( do
liftIO $ renameFile (downloaddir </> f) dest
-- The downloaddir is not removed here,
-- so if aria downloaded parts of other
-- files, and this is called again, it will
-- resume where it left off.
-- withOtherTmp registers a cleanup action
-- that will clean up leftover files when
-- git-annex terminates.
return True
, return False
)
where
download torrent tmpdir = ariaProgress (fromKey keySize k) p
[ Param $ "--select-file=" ++ show filenum
, File torrent
, Param "-d"
, File tmpdir
, Param "--seed-time=0"
, Param "--summary-interval=0"
, Param "--file-allocation=none"
-- Needed so aria will resume partially downloaded files
-- in multi-file torrents.
, Param "--check-integrity=true"
]
{- aria2c will create part of the directory structure
- contained in the torrent. It may download parts of other files
- in addition to the one we asked for. So, we need to find
- out the filename we want based on the filenum.
-}
wantedfile torrent = do
fs <- liftIO $ map fst <$> torrentFileSizes torrent
if length fs >= filenum
then return (fs !! (filenum - 1))
else giveup "Number of files in torrent seems to have changed."
checkDependencies :: Annex ()
checkDependencies = do
missing <- liftIO $ filterM (not <$$> inPath) deps
unless (null missing) $
giveup $ "need to install additional software in order to download from bittorrent: " ++ unwords missing
where
deps =
[ "aria2c"
#ifndef WITH_TORRENTPARSER
, "btshowmetainfo"
#endif
]
ariaParams :: [CommandParam] -> Annex [CommandParam]
ariaParams ps = do
opts <- map Param . annexAriaTorrentOptions <$> Annex.getGitConfig
return (ps ++ opts)
runAria :: [CommandParam] -> Annex Bool
runAria ps = progressCommand "aria2c" =<< ariaParams ps
-- Parse aria output to find "(n%)" and update the progress meter
-- with it.
ariaProgress :: Maybe Integer -> MeterUpdate -> [CommandParam] -> Annex Bool
ariaProgress Nothing _ ps = runAria ps
ariaProgress (Just sz) meter ps = do
oh <- mkOutputHandler
liftIO . commandMeter (parseAriaProgress sz) oh meter "aria2c"
=<< ariaParams ps
parseAriaProgress :: Integer -> ProgressParser
parseAriaProgress totalsize = go [] . reverse . splitc '\r'
where
go remainder [] = (Nothing, remainder)
go remainder (x:xs) = case readish (findpercent x) of
Nothing -> go (x++remainder) xs
Just p -> (Just (frompercent p), remainder)
-- "(N%)"
findpercent = takeWhile (/= '%') . drop 1 . dropWhile (/= '(')
frompercent p = toBytesProcessed $ totalsize * p `div` 100
{- Used only if the haskell torrent library is not available. -}
#ifndef WITH_TORRENTPARSER
btshowmetainfo :: FilePath -> String -> IO [String]
btshowmetainfo torrent field =
findfield [] . lines <$> readProcess "btshowmetainfo" [torrent]
where
findfield c [] = reverse c
findfield c (l:ls)
| l == fieldkey = multiline c ls
| fieldkey `isPrefixOf` l =
findfield ((drop (length fieldkey) l):c) ls
| otherwise = findfield c ls
multiline c (l:ls)
| " " `isPrefixOf` l = multiline (drop 3 l:c) ls
| otherwise = findfield c ls
multiline c [] = findfield c []
fieldkey = field ++ take (14 - length field) (repeat '.') ++ ": "
#endif
{- Examines the torrent file and gets the list of files in it,
- and their sizes.
-}
torrentFileSizes :: FilePath -> IO [(FilePath, Integer)]
torrentFileSizes torrent = do
#ifdef WITH_TORRENTPARSER
let mkfile = joinPath . map (scrub . decodeBL)
b <- B.readFile torrent
return $ case readTorrent b of
Left e -> giveup $ "failed to parse torrent: " ++ e
Right t -> case tInfo t of
SingleFile { tLength = l, tName = f } ->
[ (mkfile [f], l) ]
MultiFile { tFiles = fs, tName = dir } ->
map (\tf -> (mkfile $ dir:filePath tf, fileLength tf)) fs
where
#else
files <- getfield "files"
if null files
then do
fnl <- getfield "file name"
szl <- map readish <$> getfield "file size"
case (fnl, szl) of
((fn:[]), (Just sz:[])) -> return [(scrub fn, sz)]
_ -> parsefailed (show (fnl, szl))
else do
v <- getfield "directory name"
case v of
(d:[]) -> return $ map (splitsize d) files
_ -> parsefailed (show v)
where
getfield = btshowmetainfo torrent
parsefailed s = giveup $ "failed to parse btshowmetainfo output for torrent file: " ++ show s
-- btshowmetainfo outputs a list of "filename (size)"
splitsize d l = (scrub (d </> fn), sz)
where
sz = fromMaybe (parsefailed l) $ readish $
reverse $ takeWhile (/= '(') $ dropWhile (== ')') $
reverse l
fn = reverse $ drop 2 $
dropWhile (/= '(') $ dropWhile (== ')') $ reverse l
#endif
-- a malicious torrent file might try to do directory traversal
scrub f = if isAbsolute f || any (== "..") (splitPath f)
then giveup "found unsafe filename in torrent!"
else f
torrentContents :: URLString -> Annex UrlContents
torrentContents u = convert
<$> (liftIO . torrentFileSizes =<< tmpTorrentFile u)
where
convert [(fn, sz)] = UrlContents (Just sz) (Just fn)
convert l = UrlMulti $ map mkmulti (zip l [1..])
mkmulti ((fn, sz), n) =
(torrentUrlWithNum u n, Just sz, joinPath $ drop 1 $ splitPath fn)