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|
{- git-annex assistant webapp configurator for pairing
-
- Pairing works like this:
-
- * The user opens StartPairR, which prompts them for a secret.
- * The user submits it. The pairing secret is stored for later.
- A PairReq is broadcast out.
- * On another device, it's received, and that causes its webapp to
- display an Alert.
- * The user there clicks the button, which opens FinishPairR,
- which prompts them for the same secret.
- * The secret is used to verify the PairReq. If it checks out,
- a PairAck is sent, and the other device adds the ssh key from the
- PairReq to its authorized_keys, and sets up the remote.
- * The PairAck is received back at the device that started the process.
- It's verified using the stored secret. The ssh key from the PairAck
- is added. An Alert is displayed noting that the pairing has been set
- up. The pairing secret is removed to prevent anyone cracking the
- crypto. Syncing starts. A PairDone is sent.
- * The PairDone is received, and an alert shown indicating pairing is
- done.
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE TypeFamilies, QuasiQuotes, MultiParamTypeClasses, TemplateHaskell, OverloadedStrings, RankNTypes #-}
{-# LANGUAGE CPP #-}
module Assistant.WebApp.Configurators.Pairing where
import Assistant.Pairing
import Assistant.WebApp
import Assistant.WebApp.Types
import Assistant.WebApp.SideBar
import Utility.Yesod
#ifdef WITH_PAIRING
import Assistant.Common
import Assistant.Pairing.Network
import Assistant.Ssh
import qualified Assistant.WebApp.Configurators.Ssh as Ssh
import Assistant.Alert
import Assistant.DaemonStatus
import Utility.Verifiable
import Utility.Network
#endif
import Yesod
import Data.Text (Text)
#ifdef WITH_PAIRING
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Data.ByteString.Lazy as B
import Data.Char
import System.Posix.User
import qualified Control.Exception as E
import Control.Concurrent
#endif
getStartPairR :: Handler RepHtml
#ifdef WITH_PAIRING
getStartPairR = do
keypair <- liftIO genSshKeyPair
promptSecret Nothing $ startPairing PairReq keypair noop
#else
getStartPairR = noPairing
#endif
getFinishPairR :: PairMsg -> Handler RepHtml
#ifdef WITH_PAIRING
getFinishPairR msg = promptSecret (Just msg) $ \_ secret -> do
keypair <- setup
startPairing PairAck keypair cleanup "" secret
where
pubkey = remoteSshPubKey $ pairMsgData msg
setup = do
validateSshPubKey pubKey
unlessM (liftIO $ makeAuthorizedKeys False pubkey) $
error "failed setting up ssh authorized keys"
keypair <- liftIO genSshKeyPair
sshdata <- liftIO $ pairMsgToSshData msg
sshdata' <- liftIO $ setupSshKeyPair keypair sshdata
void $ lift $ Ssh.makeSshWithKeyPair False sshdata' (Just keypair)
return keypair
cleanup = error "TODO clean up authorized keys and generated ssh key and remove git remote"
#else
getFinishPairR _ = noPairing
#endif
{- Mostly a straightforward conversion. Except:
- * Determine the best hostname to use to contact the host.
- * Strip leading ~/ from the directory name.
-}
pairMsgToSshData :: PairMsg -> IO SshData
pairMsgToSshData msg = do
let d = pairMsgData msg
hostname <- liftIO $ bestHostName d
let dir = case remoteDirectory d of
('~':'/':v) -> v
v -> v
return $ SshData
{ sshHostName = T.pack hostname
, sshUserName = Just (T.pack $ remoteUserName d)
, sshDirectory = T.pack dir
, sshRepoName = genSshRepoName besthostname dir
, needsPubKey = True
, rsyncOnly = False
}
getInprogressPairR :: Text -> Handler RepHtml
#ifdef WITH_PAIRING
getInprogressPairR secret = pairPage $ do
$(widgetFile "configurators/pairing/inprogress")
#else
getInprogressPairR _ = noPairing
#endif
#ifdef WITH_PAIRING
{- Starts pairing, at either the PairReq (initiating host) or
- PairAck (responding host) stage.
-
- Displays an alert, and starts a thread sending the pairing message,
- which will continue running until the other host responds, or until
- canceled by the user. If canceled by the user, runs the oncancel action.
-
- Redirects to the pairing in progress page.
-}
startPairing :: PairStage -> SshKeyPair -> IO () -> Text -> Secret -> Widget
startPairing stage keypair oncancel displaysecret secret = do
dstatus <- daemonStatus <$> lift getYesod
urlrender <- lift getUrlRender
let homeurl = urlrender HomeR
sender <- mksender
liftIO $ do
pip <- PairingInProgress secret
<$> sendrequests sender dstatus homeurl
<*> pure keypair
oldpip <- modifyDaemonStatus dstatus $
\s -> (s { pairingInProgress = Just pip }, pairingInProgress s)
maybe noop stopold oldpip
lift $ redirect $ InprogressPairR displaysecret
where
mksender = do
hostname <- liftIO getHostname
username <- liftIO getUserName
reldir <- fromJust . relDir <$> lift getYesod
return $ multicastPairMsg $ \addr -> PairMsg $ mkVerifiable
(stage, PairData hostname addr username reldir (sshPubKey keypair)) secret
{- Sends pairing messages until the thread is killed,
- and shows an activity alert while doing it.
-
- The cancel button returns the user to the HomeR. This is
- not ideal, but they have to be sent somewhere, and could
- have been on a page specific to the in-process pairing
- that just stopped, so can't go back there.
-}
sendrequests sender dstatus homeurl = forkIO $ do
tid <- myThreadId
let selfdestruct = AlertButton
{ buttonLabel = "Cancel"
, buttonUrl = homeurl
, buttonAction = Just $ const $ do
oncancel
killThread tid
}
alertDuring dstatus (pairingAlert selfdestruct) $ do
_ <- E.try sender :: IO (Either E.SomeException ())
return ()
stopold = killThread . inProgressThreadId
data InputSecret = InputSecret { secretText :: Maybe Text }
{- If a PairMsg is passed in, ensures that the user enters a secret
- that can validate it. -}
promptSecret :: Maybe PairMsg -> (Text -> Secret -> Widget) -> Handler RepHtml
promptSecret msg cont = pairPage $ do
((result, form), enctype) <- lift $
runFormGet $ renderBootstrap $
InputSecret <$> aopt textField "Secret phrase" Nothing
case result of
FormSuccess v -> do
let rawsecret = fromMaybe "" $ secretText v
let secret = toSecret rawsecret
case msg of
Nothing -> case secretProblem secret of
Nothing -> cont rawsecret secret
Just problem ->
showform form enctype $ Just problem
Just m ->
if verify (fromPairMsg m) secret
then cont rawsecret secret
else showform form enctype $ Just
"That's not the right secret phrase."
_ -> showform form enctype Nothing
where
showform form enctype mproblem = do
let start = isNothing msg
let badphrase = isJust mproblem
let problem = fromMaybe "" mproblem
let (username, hostname) = maybe ("", "")
(\(_, v) -> (T.pack $ remoteUserName v, T.pack $ fromMaybe (showAddr $ remoteAddress v) (remoteHostName v)))
(verifiableVal . fromPairMsg <$> msg)
u <- T.pack <$> liftIO getUserName
let sameusername = username == u
let authtoken = webAppFormAuthToken
$(widgetFile "configurators/pairing/prompt")
{- This counts unicode characters as more than one character,
- but that's ok; they *do* provide additional entropy. -}
secretProblem :: Secret -> Maybe Text
secretProblem s
| B.null s = Just "The secret phrase cannot be left empty. (Remember that punctuation and white space is ignored.)"
| B.length s < 7 = Just "Enter a longer secret phrase, at least 6 characters, but really, a phrase is best! This is not a password you'll need to enter every day."
| s == toSecret sampleQuote = Just "Speaking of foolishness, don't paste in the example I gave. Enter a different phrase, please!"
| otherwise = Nothing
toSecret :: Text -> Secret
toSecret s = B.fromChunks [T.encodeUtf8 $ T.toLower $ T.filter isAlphaNum s]
getUserName :: IO String
getUserName = userName <$> (getUserEntryForID =<< getEffectiveUserID)
pairPage :: Widget -> Handler RepHtml
pairPage w = bootstrap (Just Config) $ do
sideBarDisplay
setTitle "Pairing"
w
{- From Dickens -}
sampleQuote :: Text
sampleQuote = T.unwords
[ "It was the best of times,"
, "it was the worst of times,"
, "it was the age of wisdom,"
, "it was the age of foolishness."
]
#else
noPairing :: Handler RepHtml
noPairing = pairPage $
$(widgetFile "configurators/pairing/disabled")
#endif
|
