git-annex/Command/Multicast.hs
Joey Hess 00dbe35fbc
allow matching on files whose content is not present
Anything that needs to examine the file content will fail to match,
or fall back to other available information. But the intent is that the
matcher be checked for matchNeedsFileContent and only be used if it does
not, so the exact behavior doesn't much matter as it should never
happen.

The real point of this is to not need to provide a dummy content file
when matching.

This commit was sponsored by Martin D on Patreon.
2020-09-28 11:17:46 -04:00

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{- git-annex command
-
- Copyright 2017 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Command.Multicast where
import Command
import Logs.Multicast
import Annex.Multicast
import Annex.WorkTree
import Annex.Content
import Annex.UUID
import Annex.Perms
import Utility.FileMode
#ifndef mingw32_HOST_OS
import Creds
#endif
import qualified Limit
import Types.FileMatcher
import qualified Git.LsFiles as LsFiles
import Utility.Hash
import Utility.Tmp
import Utility.Tmp.Dir
import Utility.Process.Transcript
import Data.Char
import qualified Data.ByteString.Lazy.UTF8 as B8
import qualified Data.Map as M
import Control.Concurrent.Async
cmd :: Command
cmd = command "multicast" SectionCommon "multicast file distribution"
paramNothing (seek <$$> optParser)
data MultiCastAction
= GenAddress
| Send
| Receive
deriving (Show)
data MultiCastOptions = MultiCastOptions MultiCastAction [CommandParam] [FilePath]
deriving (Show)
optParser :: CmdParamsDesc -> Parser MultiCastOptions
optParser _ = MultiCastOptions
<$> (genaddressp <|> sendp <|> receivep)
<*> many uftpopt
<*> cmdParams paramPaths
where
genaddressp = flag' GenAddress
( long "gen-address"
<> help "generate multicast encryption key and store address in git-annex branch"
)
sendp = flag' Send
( long "send"
<> help "multicast files"
)
receivep = flag' Receive
( long "receive"
<> help "listen for multicast files and store in repository"
)
uftpopt = Param <$> strOption
( long "uftp-opt"
<> short 'U'
<> help "passed on to uftp/uftpd"
<> metavar "OPTION"
)
seek :: MultiCastOptions -> CommandSeek
seek (MultiCastOptions GenAddress _ _) = commandAction genAddress
seek (MultiCastOptions Send ups fs) = commandAction $ send ups fs
seek (MultiCastOptions Receive ups []) = commandAction $ receive ups
seek (MultiCastOptions Receive _ _) = giveup "Cannot specify list of files with --receive; this receives whatever files the sender chooses to send."
genAddress :: CommandStart
genAddress = starting "gen-address" (ActionItemOther Nothing) (SeekInput []) $ do
k <- uftpKey
(s, ok) <- case k of
KeyContainer s -> liftIO $ genkey (Param s)
KeyFile f -> do
createAnnexDirectory (takeDirectory f)
liftIO $ nukeFile f
liftIO $ protectedOutput $ genkey (File f)
case (ok, parseFingerprint s) of
(False, _) -> giveup $ "uftp_keymgt failed: " ++ s
(_, Nothing) -> giveup $ "Failed to find fingerprint in uftp_keymgt output: " ++ s
(True, Just fp) -> next $ do
recordFingerprint fp =<< getUUID
return True
where
-- Annoyingly, the fingerprint is output to stderr.
genkey p = processTranscript "uftp_keymgt" ps Nothing
where
ps = toCommand $
[ Param "-g"
, keyparam
, p
]
-- uftp only supports rsa up to 2048 which is on the lower
-- limit of secure RSA key sizes. Instead, use an EC curve.
-- Except for on Windows XP, secp521r1 is supported on all
-- platforms by uftp. DJB thinks it's pretty good compared
-- with other NIST curves: "there's one standard NIST curve
-- using a nice prime, namely 25211 but the sheer size of this
-- prime makes it much slower than NIST P-256"
-- (http://blog.cr.yp.to/20140323-ecdsa.html)
-- Since this key is only used to set up the block encryption,
-- its slow speed is ok.
keyparam = Param "ec:secp521r1"
parseFingerprint :: String -> Maybe Fingerprint
parseFingerprint = Fingerprint <$$> lastMaybe . filter isfingerprint . words
where
isfingerprint s =
let os = filter (all isHexDigit) (splitc ':' s)
in length os == 20
send :: [CommandParam] -> [FilePath] -> CommandStart
send ups fs = do
-- Need to be able to send files with the names of git-annex
-- keys, and uftp does not allow renaming the files that are sent.
-- In a direct mode repository, the annex objects do not have
-- the names of keys, and would have to be copied, which is too
-- expensive.
starting "sending files" (ActionItemOther Nothing) (SeekInput []) $
withTmpFile "send" $ \t h -> do
let ww = WarnUnmatchLsFiles
(fs', cleanup) <- seekHelper id ww LsFiles.inRepo
=<< workTreeItems ww fs
matcher <- Limit.getMatcher
let addlist f o = whenM (matcher $ MatchingFile $ FileInfo (Just f) f) $
liftIO $ hPutStrLn h o
forM_ fs' $ \(_, f) -> do
mk <- lookupKey f
case mk of
Nothing -> noop
Just k -> withObjectLoc k $
addlist f . fromRawFilePath
liftIO $ hClose h
liftIO $ void cleanup
serverkey <- uftpKey
u <- getUUID
withAuthList $ \authlist -> do
let ps =
-- Force client authentication.
[ Param "-c"
, Param "-Y", Param "aes256-cbc"
, Param "-h", Param "sha512"
-- Picked ecdh_ecdsa for perfect forward secrecy,
-- and because a EC key exchange algorithm is
-- needed since all keys are EC.
, Param "-e", Param "ecdh_ecdsa"
, Param "-k", uftpKeyParam serverkey
, Param "-U", Param (uftpUID u)
-- only allow clients on the authlist
, Param "-H", Param ("@"++authlist)
-- pass in list of files to send
, Param "-i", File t
] ++ ups
liftIO (boolSystem "uftp" ps) >>= showEndResult
next $ return True
receive :: [CommandParam] -> CommandStart
receive ups = starting "receiving multicast files" ai si $ do
showNote "Will continue to run until stopped by ctrl-c"
showOutput
clientkey <- uftpKey
u <- getUUID
(callback, environ, statush) <- liftIO multicastCallbackEnv
tmpobjdir <- fromRepo gitAnnexTmpObjectDir
createAnnexDirectory tmpobjdir
withTmpDirIn tmpobjdir "multicast" $ \tmpdir -> withAuthList $ \authlist -> do
abstmpdir <- liftIO $ absPath tmpdir
abscallback <- liftIO $ searchPath callback
let ps =
-- Avoid it running as a daemon.
[ Param "-d"
-- Require encryption.
, Param "-E"
, Param "-k", uftpKeyParam clientkey
, Param "-U", Param (uftpUID u)
-- Only allow servers on the authlist
, Param "-S", Param authlist
-- Receive files into tmpdir
-- (it needs an absolute path)
, Param "-D", File abstmpdir
-- Run callback after each file received
-- (it needs an absolute path)
, Param "-s", Param (fromMaybe callback abscallback)
] ++ ups
runner <- liftIO $ async $
hClose statush
`after` boolSystemEnv "uftpd" ps (Just environ)
mapM_ storeReceived . lines =<< liftIO (hGetContents statush)
showEndResult =<< liftIO (wait runner)
next $ return True
where
ai = ActionItemOther Nothing
si = SeekInput []
storeReceived :: FilePath -> Annex ()
storeReceived f = do
case deserializeKey (takeFileName f) of
Nothing -> do
warning $ "Received a file " ++ f ++ " that is not a git-annex key. Deleting this file."
liftIO $ nukeFile f
Just k -> void $
getViaTmpFromDisk RetrievalVerifiableKeysSecure AlwaysVerify k $ \dest -> unVerified $
liftIO $ catchBoolIO $ do
rename f dest
return True
-- Under Windows, uftp uses key containers, which are not files on the
-- filesystem.
data UftpKey = KeyFile FilePath | KeyContainer String
uftpKeyParam :: UftpKey -> CommandParam
uftpKeyParam (KeyFile f) = File f
uftpKeyParam (KeyContainer s) = Param s
uftpKey :: Annex UftpKey
#ifdef mingw32_HOST_OS
uftpKey = do
u <- getUUID
return $ KeyContainer $ "annex-" ++ fromUUID u
#else
uftpKey = KeyFile <$> credsFile "multicast"
#endif
-- uftp needs a unique UID for each client and server, which
-- is a 8 digit hex number in the form "0xnnnnnnnn"
-- Derive it from the UUID.
uftpUID :: UUID -> String
uftpUID u = "0x" ++ (take 8 $ show $ sha2_256 $ B8.fromString (fromUUID u))
withAuthList :: (FilePath -> Annex a) -> Annex a
withAuthList a = do
m <- knownFingerPrints
withTmpFile "authlist" $ \t h -> do
liftIO $ hPutStr h (genAuthList m)
liftIO $ hClose h
a t
genAuthList :: M.Map UUID Fingerprint -> String
genAuthList = unlines . map fmt . M.toList
where
fmt (u, Fingerprint f) = uftpUID u ++ "|" ++ f