path: root/lib/Kiki.hs

{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
module Kiki where

import Control.Applicative
import Control.Arrow
import Control.Concurrent
import Control.Exception
import Control.Monad
import Data.ASN1.BinaryEncoding
import Data.ASN1.Encoding
import Data.ASN1.Types
import Data.Binary
import Data.Char
import Data.List
import Data.Maybe
import Data.Monoid
import Data.OpenPGP
import Data.OpenPGP.Util
import Data.Ord
import System.Directory
import System.FilePath.Posix
import System.IO
import System.IO.Temp
import System.IO.Error
import System.Posix.IO as Posix (createPipe)
import System.Posix.User
import System.Process
import System.Posix.Files
import qualified Data.Traversable as T (mapM)
#if defined(VERSION_memory)
import qualified Data.ByteString.Char8 as S8
import Data.ByteArray.Encoding
#elif defined(VERSION_dataenc)
import qualified Codec.Binary.Base64 as Base64
#endif
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString.Lazy.Char8 as Char8
import qualified Data.Map.Strict as Map
import qualified SSHKey as SSH

import GnuPGAgent (Query(..))
import CommandLine
import KeyRing
import DotLock

withAgent :: [PassphraseSpec] -> [PassphraseSpec]
withAgent [] = [PassphraseAgent]
withAgent ps = ps

ciphername Unencrypted = "-"
ciphername TripleDES   = "3des"
ciphername (SymmetricAlgorithm w8) = "cipher-"++show w8
ciphername c = map toLower $ show c

-- |
-- Regenerate /var/cache/kiki
refresh :: (FilePath -> FilePath) -> CommonArgsParsed -> IO ()
refresh root homepass = do
    let homepass' = homepass { cap_homespec = fmap root (cap_homespec homepass) }
    KikiResult r report <- runKeyRing $ minimalOp homepass'
    let mroot = case root "" of
                    "/" -> Nothing
                    ""  -> Nothing
                    pth -> Just pth
    case r of
        KikiSuccess rt -> refreshCache rt mroot
        _ -> return () -- XXX: silent fail?

data CommonArgsParsed = CommonArgsParsed { cap_homespec :: Maybe String, cap_passfd :: Maybe InputFile }

streaminfo :: StreamInfo
streaminfo = StreamInfo
    { fill = KF_None
    , spill = KF_None
    , typ = KeyRingFile
    , initializer = NoCreate
    , access = AutoAccess
    , transforms = []
    }

minimalOp :: CommonArgsParsed -> KeyRingOperation
minimalOp cap = op
 where
    streaminfo = StreamInfo { fill = KF_None
                            , typ = KeyRingFile
                            , spill = KF_All
                            , initializer = NoCreate
                            , access = AutoAccess
                            , transforms = []
                            }
    op = KeyRingOperation
        { opFiles = Map.fromList $
            [ ( HomeSec, streaminfo { access = Sec })
            , ( HomePub, streaminfo { access = Pub })
            ]
        , opPassphrases = withAgent $ do pfile <- maybeToList (cap_passfd cap)
                                         return $ PassphraseSpec Nothing Nothing pfile
        , opTransforms = []
        , opHome = cap_homespec cap
        }

run :: [String] -> Args (IO ()) -> IO ()
run args x =
    case runArgs (parseInvocation (uncurry fancy kikiOptions "") args) x of
        Left e   -> hPutStrLn stderr $ usageErrorMessage e
        Right io -> io

outputReport :: [(FilePath, KikiReportAction)] -> IO ()
outputReport report = do
    forM_ report $ \(fname,act) -> do
        putStrLn $ fname ++ ": " ++ reportString act

importAndRefresh :: (FilePath -> FilePath) -> CommonArgsParsed -> IO ()
importAndRefresh root cmn = do
    let rootdir = do guard (root "x" /= "x")
                     Just $ root ""

    me <- getEffectiveUserID

    let noChrootArg = rootdir == Nothing
        bUnprivileged = (me/=0) && noChrootArg
    if rootdir==Just "" then error "--chroot requires an argument" else do

    let homespec = mplus (slash <$> rootdir <*> cap_homespec cmn)
                         (fmap (++"/root/.gnupg") rootdir)
        sshkeygen size = Just $ concat [ "mkdir -p \"$(dirname $file)\" && "
                                       , "ssh-keygen -P \"\" -q -f $file -b "
                                       , show size ]
        mkdirFor path = do
            let dir = takeDirectory path
            -- putStrLn $ "mkdirFor " ++ show dir
            createDirectoryIfMissing True dir
        -- ssl = Just "mkdir -p \"$(dirname $file)\" && openssl genrsa -out $file 1024"
    (home,secring,pubring,mbwk) <- unconditionally $ getHomeDir homespec
    osHomeDir <- if bUnprivileged then getHomeDirectory else return "/root"

    old_umask <- setFileCreationMask(0o077);
    -- Generate secring.gpg if it does not exist...
    gotsec <- doesFileExist secring

    let passfd = cap_passfd cmn

    (torgen,pwds) <-
     if gotsec
      then return (Generate 0 $ GenRSA $ 1024 `div` 8, [])
      else do
        {-  ssh-keygen to create master key...
        let mkpath = home ++ "/master-key"
        mkdirFor mkpath
        e <- systemEnv [ ("file",mkpath) ] (fromJust $ sshkeygen 4096)
        case e of
            ExitFailure num -> error "ssh-keygen failed to create master key"
            ExitSuccess     -> return ()
        [PEMPacket mk] <- readSecretPEMFile (ArgFile mkpath)
        writeInputFileL (InputFileContext secring pubring)
                        HomeSec
                        ( encode $ Message [mk { is_subkey = False }] )
        -}
        master_un <- (\k -> MappedPacket (k { is_subkey = False }) Map.empty) <$> generateKey (GenRSA $ 4096 `div` 8 )
        tor_un <- generateKey (GenRSA $ 1024 `div` 8 )
        (read_tor,write_tor) <- Posix.createPipe
        do rs <- writeKeyToFile (streaminfo { typ = PEMFile, access = Sec, spill = KF_Match "tor", fill = KF_All }) (FileDesc write_tor) tor_un
           -- outputReport $ map (first show) rs
           return ()
        let default_cipher = (CAST5 {- AES128 -}, IteratedSaltedS2K SHA1 4073382889203176146 7864320)
            ctx = InputFileContext secring pubring
            main_passwds = withAgent $ do pfd <- maybeToList passfd
                                          return $ PassphraseSpec Nothing Nothing pfd
            passwordop = KeyRingOperation
                            { opFiles = Map.empty
                            -- TODO: ask agent for new passphrase
                            , opPassphrases = main_passwds
                            , opHome = homespec
                            , opTransforms = []
                            }
        let uidentry = Map.singleton (keykey $ packet master_un)
                        $ master_un { packet = Query (packet master_un)
                                                     (torUIDFromKey tor_un)
                                                     Nothing
                                    }
        transcoder <- makeMemoizingDecrypter passwordop ctx (Just master_un, uidentry)
        master0 <- transcoder default_cipher master_un
        case master0 of
            KikiSuccess master -> do
                mkdirFor secring
                writeInputFileL ctx
                                HomeSec
                                $ encode $ Message [master]
                putStrLn "Wrote master key"
                return (FileDesc read_tor, [PassphraseMemoizer transcoder])
            er -> do
                hPutStrLn stderr ("warning: " ++ errorString er)
                hPutStrLn stderr "warning: keys will not be encrypted.";
                mkdirFor secring
                writeInputFileL ctx
                                HomeSec
                                $ encode $ Message [packet master_un]
                putStrLn "Wrote master key"
                return (Generate 0 (GenRSA $ 1024 `div` 8 ), [])
    gotpub <- doesFileExist pubring
    when (not gotpub) $ do
        mkdirFor pubring
        writeInputFileL (InputFileContext secring pubring)
                        HomePub
                        ( encode $ Message [] )

    setFileCreationMask(old_umask);
    -- Old paths..
    --
    -- Private
    -- pem tor        /var/lib/tor/samizdat/private_key
    -- pem ssh-client %(home)/.ssh/id_rsa
    -- pem ssh-server /etc/ssh/ssh_host_rsa_key
    -- pem ipsec      /etc/ipsec.d/private/%(onion).pem

    -- Public
    -- ssh-client %(home)/.ssh/id_rsa.pub
    -- ssh-server /etc/ssh/ssh_host_rsa_key.pub
    -- ipsec      /etc/ipsec.d/certs/%(onion).pem

    -- First, we ensure that the tor key exists and is imported
    -- so that we know where to put the strongswan key.
    let strm = StreamInfo { typ = KeyRingFile
                          , fill = KF_None
                          , spill = KF_All
                          , access = AutoAccess
                          , initializer = NoCreate
                          , transforms = [] }
        buildStreamInfo rtyp ftyp = StreamInfo { typ = ftyp
                                               , fill = rtyp
                                               , spill = KF_All
                                               , access = AutoAccess
                                               , initializer = NoCreate
                                               , transforms = [] }
        peminfo bits usage =
                  StreamInfo { typ = PEMFile
                             , fill = KF_None -- KF_Match usage
                             , spill = KF_Match usage
                             , access = Sec
                             , initializer = Internal (GenRSA $ bits `div` 8)
                             , transforms = []
                             }
        sshcpath = fromMaybe "" rootdir ++ osHomeDir ++ ".ssh/id_rsa"
        sshspath = fromMaybe "" rootdir ++ "/etc/ssh/ssh_host_rsa_key"
        op = KeyRingOperation
             { opFiles = Map.fromList $
                [ ( HomeSec, buildStreamInfo KF_All KeyRingFile )
                , ( HomePub, (buildStreamInfo KF_All KeyRingFile) { access = Pub } )
                , ( torgen , case torgen of
                                FileDesc _ -> StreamInfo { typ = PEMFile
                                                         , fill = KF_Match "tor"
                                                         , spill = KF_Match "tor"
                                                         , access = Sec
                                                         , initializer = NoCreate
                                                         , transforms = [] }
                                _          -> strm { spill = KF_Match "tor" })
                , ( Generate 1 (GenRSA (1024 `div` 8)), strm { spill = KF_Match "ipsec" })
                , ( ArgFile sshcpath, (peminfo 2048 "ssh-client") )
                , ( ArgFile sshspath, (peminfo 2048 "ssh-server") )
                ]
             , opPassphrases = withAgent $ pwds ++ do pfd <- maybeToList passfd
                                                      return $ PassphraseSpec Nothing Nothing pfd
             , opHome = homespec
             , opTransforms = []
             }
        -- doNothing = return ()
        nop = KeyRingOperation
            { opFiles = Map.empty
            , opPassphrases = withAgent $ do pfd <- maybeToList passfd
                                             return $ PassphraseSpec Nothing Nothing pfd
            , opHome=homespec, opTransforms = []
            }
    -- if bUnprivileged then doNothing else mkdirFor torpath
    KikiResult rt report <- runKeyRing (if bUnprivileged then nop else op)
    outputReport report
    rt <- case rt of
        BadPassphrase ->
            error "Operation requires correct passphrase. (Hint: Use --passphrase-fd=0 to input it on stdin.)"
        _ -> unconditionally $ return rt

    when (not bUnprivileged) $ refreshCache rt rootdir


refreshCache :: KeyRingRuntime -> Maybe FilePath -> IO ()
refreshCache rt rootdir = do

    let getMkPathAndCommit destdir = do
            let cachedir = takeDirectory destdir
                unslash ('/':xs) = xs
                unslash xs = xs
                timeout = -1 -- TODO: set milisecond timeout on dotlock
            createDirectoryIfMissing True cachedir
            tmpdir <- createTempDirectory cachedir ("transaction." ++ takeBaseName destdir)
            createSymbolicLink tmpdir (tmpdir ++ ".link")
            lock <- dotlock_create destdir 0
            T.mapM (flip dotlock_take timeout) lock
            let mkpath pth = tmpdir </> unslash (makeRelative destdir pth)
                commit     = do
                    oldcommit <- (Just <$> readSymbolicLink destdir)
                                    `catch` \e -> do
                                        when (not $ isDoesNotExistError e) $ warn (show e)
                                        return Nothing
                    -- Note: Files not written to are considered deleted,
                    --       otherwise call readyReadBeforeWrite on them.
                    rename (tmpdir ++ ".link") destdir
                    er <- T.mapM dotlock_release lock
                    void $ T.mapM removeDirectoryRecursive oldcommit
            -- Present transaction is Write only (or Write-Before-Read) which is fine.
            -- If ever Read-Before-Write is required, uncomment and use:
            -- let readyReadBeforeWrite pth = do
            --    let copyIt = do
            --          createDirectoryIfMissing True (takeDirectory (mkpath pth))
            --          copyFile (destdir </> unslash (makeRelative destdir pth) (mkpath pth)
            --    doesFileExist (mkpath pth) >>= flip when copyIt
            --    return (mkpath pth)
            return (mkpath, commit {-, readyReadBeforeWrite -})
    (mkpath, commit) <- getMkPathAndCommit (fromMaybe "" rootdir ++ "/var/cache/kiki/config")

    -- Generete hosts file.
    let hostspath = mkpath "hosts"
        op = KeyRingOperation
             { opFiles = Map.fromList $
                [ ( HomePub, streaminfo { typ=KeyRingFile, spill=KF_All, access=Pub } )
                , ( ArgFile hostspath, streaminfo { typ=Hosts, spill=KF_None, fill=KF_All, access=Pub } )
                ]
             , opPassphrases = []
             , opHome = Just $ takeDirectory (rtPubring rt)
             , opTransforms = []
             }
    KikiResult _ report <- runKeyRing op
    outputReport report

    let write' wr f bs = do
            createDirectoryIfMissing True $ takeDirectory f
            wr f bs
        write = write' writeFile
        writeL = write' L.writeFile

    let names = do wk <- rtWorkingKey rt
                   -- XXX unnecessary signature check
                   return $ getHostnames (rtKeyDB rt Map.! keykey wk)
        bUnprivileged = False -- TODO
        oname = Char8.concat $ do
            (_,(os,_)) <- maybeToList names
            take 1 os
    fromMaybe (error "No working key.") $ do
    (wkaddr,_) <- names
    Just $ do
    if (oname == "") && (not bUnprivileged) then error "Missing tor key" else do
    -- sshcpathpub0 = fromMaybe "" rootdir ++ osHomeDir </> ".ssh" </> "id_rsa.pub"
    -- sshspathpub0 = fromMaybe "" rootdir ++ "/etc/ssh/ssh_host_rsa_key.pub"
    -- contactipsec0 = fromMaybe "" rootdir ++ "/etc/ipsec.d/certs/%(onion).pem"

    flip (maybe $ warn "missing working key?") (rtWorkingKey rt) $ \wk -> do

    let grip = fingerprint wk
        wkkd = rtKeyDB rt Map.! keykey wk
        getSecret tag = sortOn (Down . timestamp)
                        $ getSubkeys Unsigned wk (keySubKeys wkkd) tag

    let writeSecret tag path warning = do
        let my_ks :: [Packet]
            my_ks = getSecret "ipsec"
        case my_ks of
            se0:_ -> do sc1 <- rtPassphrases rt (Unencrypted,S2K 100 "") $ MappedPacket se0 Map.empty
                        let sec = case sc1 of
                                    KikiSuccess s -> s
                                    _             -> se0
                        report <- writeKeyToFile streaminfo { typ = PEMFile
                                                            , access = Sec
                                                            , spill = KF_All
                                                            }
                                                 (ArgFile path)
                                                 sec
                        let ctx = Just $ InputFileContext "secring.gpg" "pubring.gpg"
                        outputReport $ map (first $ resolveForReport ctx)
                                     $ filter ((/=ExportedSubkey) . snd) report
            _     -> warn warning

    writeSecret "ipsec"
                (mkpath "ipsec.d/private/" ++ Char8.unpack oname++".pem")
                "missing ipsec key?"

    writeSecret "ssh-client"
                (mkpath "root/.ssh/id_rsa")
                "missing ssh-client key?"

    writeSecret "ssh-server"
                (mkpath "ssh_host_rsa_key")
                "missing ssh host key?"

    writeSecret "tor"
                (mkpath "tor/private_key")
                "missing tor key?"

    -- Finally, export public keys if they do not exist.
    either warn (write $ mkpath "root/.ssh/id_rsa.pub")
            $ show_ssh' "ssh-client" grip (rtKeyDB rt)
    either warn (write $ mkpath "ssh_host_rsa_key.pub")
        $ show_ssh' "ssh-server" grip (rtKeyDB rt)
    either warn (write $ mkpath "ipsec.d/certs/" ++ Char8.unpack oname++".pem")
        $ show_pem' "ipsec" grip (rtKeyDB rt) pemFromPacket

    let cs = filter notme (Map.elems $ rtKeyDB rt)
        kk = keykey (fromJust $ rtWorkingKey rt)
        notme kd = keykey (keyPacket kd) /= kk

        installConctact :: KeyData -> IO Char8.ByteString
        installConctact kd = do
            -- The getHostnames command requires a valid cross-signed tor key
            -- for each onion name returned in (_,(ns,_)).
            let (addr,(ns,_)) = getHostnames kd
                contactname = fmap Char8.unpack $ listToMaybe ns -- only first onion name.
            flip (maybe $ return Char8.empty) contactname $ \contactname -> do

            let cpath = interp (Map.singleton "onion" contactname) "ipsec.d/certs/%(onion).pem"
                their_master = packet $ keyMappedPacket kd
                -- We find all cross-certified ipsec keys for the given cross-certified onion name.
                ipsecs :: [Packet]
                ipsecs = sortOn (Down . timestamp)
                         $ getSubkeys CrossSigned their_master (keySubKeys kd) "ipsec"
                           ++ getSubkeys CrossSigned their_master (keySubKeys kd) "strongswan"
            bss <- forM (take 1 ipsecs) $ \k -> do
                let warn' x = warn x >> return Char8.empty
                flip (either warn') (pemFromPacket k :: Either String String) $ \pem -> do
                    write (mkpath cpath) pem
                    return $ strongswanForContact addr contactname
            return $ Char8.concat bss

    cons <- mapM installConctact cs
    writeL (mkpath "ipsec.conf") . Char8.unlines
          $ [ "conn %default"
            , "  ikelifetime=60m"
            , "  keylife=20m"
            , "  rekeymargin=3m"
            , "  keyingtries=%forever"
            , "  keyexchange=ikev2"
            , "  dpddelay=10s"
            , "  dpdaction=restart"
            , "  left=%defaultroute"
            , "  leftsubnet=" <> Char8.pack (showA wkaddr) <> "/128"
            , "  leftauth=pubkey"
            , "  leftid=" <> Char8.pack (showA wkaddr)
            , "  leftrsasigkey=" <> oname
            , "  leftikeport=4500"
            , "  rightikeport=4500"
            , "  right=%any"
            , "  rightauth=pubkey"
            , "  type=tunnel"
            , "  auto=route"
            , ""
            ] ++ filter (not . Char8.null) cons
    commit

strongswanForContact addr oname = Char8.unlines
    [ "conn " <> p oname
    , "  right=%" <> p oname <> ".ipv4"
    , "  rightsubnet=" <> p (showA addr) <> "/128"
    , "  rightauth=pubkey"
    , "  rightid=" <> p (showA addr)
    , "  rightrsasigkey=" <> p (oname) <> ".pem"
    ]
    where p = Char8.pack

-- conn hiotuxliwisbp6mi.onion
--   right=%hiotuxliwisbp6mi.onion.ipv4
--   rightsubnet=fdcc:76c8:cb34:74e6:2aa3:cb39:abc8:d403/128
--   rightauth=pubkey
--   rightid=fdcc:76c8:cb34:74e6:2aa3:cb39:abc8:d403
--   rightrsasigkey=hiotuxliwisbp6mi.onion.pem

showA addr = if null bracket then pre else drop 1 pre
    where (pre,bracket) = break (==']') (show addr)


#if !MIN_VERSION_base(4,8,0)
sortOn :: Ord b => (a -> b) -> [a] -> [a]
sortOn f =
    map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))
#endif

pemFromPacket k = do
    let rsa = pkcs8 . fromJust $ rsaKeyFromPacket k
        der = encodeASN1 DER (toASN1 rsa [])
#if defined(VERSION_memory)
        qq  = S8.unpack $ convertToBase Base64 (L.toStrict der)
#elif defined(VERSION_dataenc)
        qq  = Base64.encode (L.unpack der)
#endif
    return $
        writePEM "PUBLIC KEY" qq -- ("TODO "++show keyspec)

show_pem keyspec wkgrip db = either warn putStrLn $ show_pem' keyspec wkgrip db pemFromPacket

show_pem' keyspec wkgrip db keyfmt = do
    let s = parseSpec wkgrip keyspec
    flip (maybe . Left $ keyspec ++ ": not found")
         (selectPublicKey s db)
         keyfmt

warn str = hPutStrLn stderr str

show_ssh keyspec wkgrip db = either warn putStrLn $ show_ssh' keyspec wkgrip db

show_ssh' keyspec wkgrip db = do
    let s = parseSpec wkgrip keyspec
    flip (maybe . Left $ keyspec ++ ": not found")
         (selectPublicKey s db)
         $ return . sshblobFromPacket

-- |
-- interpolate %var patterns in a string.
interp vars raw = es >>= interp1
 where
    gs = groupBy (\_ c -> c/='%') raw
    es = dropWhile null $ gobbleEscapes ("":gs)
            where gobbleEscapes :: [String] -> [String]
                  gobbleEscapes (a:"%":b:bs) = (a++b) : gobbleEscapes bs
                  gobbleEscapes (g:gs)       = g : gobbleEscapes gs
                  gobbleEscapes []           = []
    interp1 ('%':'(':str) = fromMaybe "" (Map.lookup key vars) ++ drop 1 rest
                            where (key,rest) = break (==')') str
    interp1 plain = plain

sshblobFromPacket k = blob
 where
    Just (RSAKey (MPI n) (MPI e)) = rsaKeyFromPacket k
    bs = SSH.keyblob (n,e)
    blob = Char8.unpack bs

replaceSshServerKeys root cmn = do
    let homepass' = cmn { cap_homespec = fmap root (cap_homespec cmn) }
        replaceSSH op = op { opFiles = files }
            where
                files = Map.adjust delssh HomeSec
                        $ Map.adjust delssh HomePub
                        $ Map.insert (ArgFile $ root "/etc/ssh/ssh_host_rsa_key") strm $ opFiles op
                strm = streaminfo { typ = PEMFile, spill = KF_Match "ssh-server", access = Sec }
                delssh strm = strm { transforms = DeleteSubkeyByUsage "ssh-server" : transforms strm
                                   , fill = KF_All }
    KikiResult r report <- runKeyRing $ minimalOp homepass'
    case r of
        KikiSuccess rt -> Kiki.refreshCache rt $ case root "" of
                                                    "/" -> Nothing
                                                    ""  -> Nothing
                                                    pth -> Just pth
        err            -> hPutStrLn stderr $ errorString err

slash :: String -> String -> String
slash "/"    ('/':xs) = '/':xs
slash ""     ('/':xs) = '/':xs
slash ""     xs       = '/':xs
slash (y:ys) xs       = y:slash ys xs

ㄧchroot :: Args (FilePath -> FilePath)
ㄧchroot = pure (\r a -> slash r a) <*> arg "--chroot" <|> pure id

ㄧhomedir :: Args CommonArgsParsed
ㄧhomedir = CommonArgsParsed
                <$> optional (arg "--homedir")
                <*> optional (FileDesc <$> read <$> arg "--passphrase-fd")

kikiOptions :: ( [(String,Int)], [String] )
kikiOptions = ( ss, ps )
 where
    ss = [("--chroot",1),("--passphrase-fd",1),("--homedir",1)]
    ps = []