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module Erebos.Pairing (
PairingService(..),
PairingState(..),
PairingAttributes(..),
PairingResult(..),
PairingFailureReason(..),
pairingRequest,
pairingAccept,
pairingReject,
) where
import Control.Monad
import Control.Monad.Except
import Control.Monad.Reader
import Crypto.Random
import Data.Bits
import Data.ByteArray (Bytes, convert)
import qualified Data.ByteArray as BA
import qualified Data.ByteString.Char8 as BC
import Data.Kind
import Data.Maybe
import Data.Typeable
import Data.Word
import Erebos.Identity
import Erebos.Network
import Erebos.PubKey
import Erebos.Service
import Erebos.State
import Erebos.Storage
data PairingService a = PairingRequest (Stored (Signed IdentityData)) (Stored (Signed IdentityData)) RefDigest
| PairingResponse Bytes
| PairingRequestNonce Bytes
| PairingAccept a
| PairingReject
data PairingState a = NoPairing
| OurRequest UnifiedIdentity UnifiedIdentity Bytes
| OurRequestConfirm (Maybe (PairingVerifiedResult a))
| OurRequestReady
| PeerRequest UnifiedIdentity UnifiedIdentity Bytes RefDigest
| PeerRequestConfirm
| PairingDone
data PairingFailureReason a = PairingUserRejected
| PairingUnexpectedMessage (PairingState a) (PairingService a)
| PairingFailedOther String
data PairingAttributes a = PairingAttributes
{ pairingHookRequest :: ServiceHandler (PairingService a) ()
, pairingHookResponse :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonce :: String -> ServiceHandler (PairingService a) ()
, pairingHookRequestNonceFailed :: ServiceHandler (PairingService a) ()
, pairingHookConfirmedResponse :: ServiceHandler (PairingService a) ()
, pairingHookConfirmedRequest :: ServiceHandler (PairingService a) ()
, pairingHookAcceptedResponse :: ServiceHandler (PairingService a) ()
, pairingHookAcceptedRequest :: ServiceHandler (PairingService a) ()
, pairingHookVerifyFailed :: ServiceHandler (PairingService a) ()
, pairingHookRejected :: ServiceHandler (PairingService a) ()
, pairingHookFailed :: PairingFailureReason a -> ServiceHandler (PairingService a) ()
}
class (Typeable a, Storable a) => PairingResult a where
type PairingVerifiedResult a :: Type
type PairingVerifiedResult a = a
pairingServiceID :: proxy a -> ServiceID
pairingVerifyResult :: a -> ServiceHandler (PairingService a) (Maybe (PairingVerifiedResult a))
pairingFinalizeRequest :: PairingVerifiedResult a -> ServiceHandler (PairingService a) ()
pairingFinalizeResponse :: ServiceHandler (PairingService a) a
defaultPairingAttributes :: proxy (PairingService a) -> PairingAttributes a
instance Storable a => Storable (PairingService a) where
store' (PairingRequest idReq idRsp x) = storeRec $ do
storeRef "id-req" idReq
storeRef "id-rsp" idRsp
storeBinary "request" x
store' (PairingResponse x) = storeRec $ storeBinary "response" x
store' (PairingRequestNonce x) = storeRec $ storeBinary "reqnonce" x
store' (PairingAccept x) = store' x
store' (PairingReject) = storeRec $ storeEmpty "reject"
load' = do
res <- loadRec $ do
(req :: Maybe Bytes) <- loadMbBinary "request"
idReq <- loadMbRef "id-req"
idRsp <- loadMbRef "id-rsp"
rsp <- loadMbBinary "response"
rnonce <- loadMbBinary "reqnonce"
rej <- loadMbEmpty "reject"
return $ catMaybes
[ PairingRequest <$> idReq <*> idRsp <*> (refDigestFromByteString =<< req)
, PairingResponse <$> rsp
, PairingRequestNonce <$> rnonce
, const PairingReject <$> rej
]
case res of
x:_ -> return x
[] -> PairingAccept <$> load'
instance PairingResult a => Service (PairingService a) where
serviceID _ = pairingServiceID @a Proxy
type ServiceAttributes (PairingService a) = PairingAttributes a
defaultServiceAttributes = defaultPairingAttributes
type ServiceState (PairingService a) = PairingState a
emptyServiceState _ = NoPairing
serviceHandler spacket = ((,fromStored spacket) <$> svcGet) >>= \case
(NoPairing, PairingRequest pdata sdata confirm) -> do
self <- maybe (throwError "failed to validate received identity") return $ validateIdentity sdata
self' <- maybe (throwError "failed to validate own identity") return .
validateExtendedIdentity . lsIdentity . fromStored =<< svcGetLocal
when (not $ self `sameIdentity` self') $ do
throwError "pairing request to different identity"
peer <- maybe (throwError "failed to validate received peer identity") return $ validateIdentity pdata
peer' <- asks $ svcPeerIdentity
when (not $ peer `sameIdentity` peer') $ do
throwError "pairing request from different identity"
join $ asks $ pairingHookRequest . svcAttributes
nonce <- liftIO $ getRandomBytes 32
svcSet $ PeerRequest peer self nonce confirm
replyPacket $ PairingResponse nonce
(NoPairing, _) -> return ()
(PairingDone, _) -> return ()
(_, PairingReject) -> do
join $ asks $ pairingHookRejected . svcAttributes
svcSet NoPairing
(OurRequest self peer nonce, PairingResponse pnonce) -> do
hook <- asks $ pairingHookResponse . svcAttributes
hook $ confirmationNumber $ nonceDigest self peer nonce pnonce
svcSet $ OurRequestConfirm Nothing
replyPacket $ PairingRequestNonce nonce
x@(OurRequest {}, _) -> reject $ uncurry PairingUnexpectedMessage x
(OurRequestConfirm _, PairingAccept x) -> do
flip catchError (reject . PairingFailedOther) $ do
pairingVerifyResult x >>= \case
Just x' -> do
join $ asks $ pairingHookConfirmedRequest . svcAttributes
svcSet $ OurRequestConfirm (Just x')
Nothing -> do
join $ asks $ pairingHookVerifyFailed . svcAttributes
svcSet NoPairing
replyPacket PairingReject
x@(OurRequestConfirm _, _) -> reject $ uncurry PairingUnexpectedMessage x
(OurRequestReady, PairingAccept x) -> do
flip catchError (reject . PairingFailedOther) $ do
pairingVerifyResult x >>= \case
Just x' -> do
pairingFinalizeRequest x'
join $ asks $ pairingHookAcceptedResponse . svcAttributes
svcSet $ PairingDone
Nothing -> do
join $ asks $ pairingHookVerifyFailed . svcAttributes
throwError ""
x@(OurRequestReady, _) -> reject $ uncurry PairingUnexpectedMessage x
(PeerRequest peer self nonce dgst, PairingRequestNonce pnonce) -> do
if dgst == nonceDigest peer self pnonce BA.empty
then do hook <- asks $ pairingHookRequestNonce . svcAttributes
hook $ confirmationNumber $ nonceDigest peer self pnonce nonce
svcSet PeerRequestConfirm
else do join $ asks $ pairingHookRequestNonceFailed . svcAttributes
svcSet NoPairing
replyPacket PairingReject
x@(PeerRequest {}, _) -> reject $ uncurry PairingUnexpectedMessage x
x@(PeerRequestConfirm, _) -> reject $ uncurry PairingUnexpectedMessage x
reject :: PairingResult a => PairingFailureReason a -> ServiceHandler (PairingService a) ()
reject reason = do
join $ asks $ flip pairingHookFailed reason . svcAttributes
svcSet NoPairing
replyPacket PairingReject
nonceDigest :: UnifiedIdentity -> UnifiedIdentity -> Bytes -> Bytes -> RefDigest
nonceDigest idReq idRsp nonceReq nonceRsp = hashToRefDigest $ serializeObject $ Rec
[ (BC.pack "id-req", RecRef $ storedRef $ idData idReq)
, (BC.pack "id-rsp", RecRef $ storedRef $ idData idRsp)
, (BC.pack "nonce-req", RecBinary $ convert nonceReq)
, (BC.pack "nonce-rsp", RecBinary $ convert nonceRsp)
]
confirmationNumber :: RefDigest -> String
confirmationNumber dgst =
case map fromIntegral $ BA.unpack dgst :: [Word32] of
(a:b:c:d:_) -> let str = show $ ((a `shift` 24) .|. (b `shift` 16) .|. (c `shift` 8) .|. d) `mod` (10 ^ len)
in replicate (len - length str) '0' ++ str
_ -> ""
where len = 6
pairingRequest :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingRequest _ peer = do
self <- liftIO $ serverIdentity $ peerServer peer
nonce <- liftIO $ getRandomBytes 32
pid <- peerIdentity peer >>= \case
PeerIdentityFull pid -> return pid
_ -> throwError "incomplete peer identity"
sendToPeerWith @(PairingService a) peer $ \case
NoPairing -> return (Just $ PairingRequest (idData self) (idData pid) (nonceDigest self pid nonce BA.empty), OurRequest self pid nonce)
_ -> throwError "already in progress"
pairingAccept :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingAccept _ peer = runPeerService @(PairingService a) peer $ do
svcGet >>= \case
NoPairing -> throwError $ "none in progress"
OurRequest {} -> throwError $ "waiting for peer"
OurRequestConfirm Nothing -> do
join $ asks $ pairingHookConfirmedResponse . svcAttributes
svcSet OurRequestReady
OurRequestConfirm (Just verified) -> do
join $ asks $ pairingHookAcceptedResponse . svcAttributes
pairingFinalizeRequest verified
svcSet PairingDone
OurRequestReady -> throwError $ "already accepted, waiting for peer"
PeerRequest {} -> throwError $ "waiting for peer"
PeerRequestConfirm -> do
join $ asks $ pairingHookAcceptedRequest . svcAttributes
replyPacket . PairingAccept =<< pairingFinalizeResponse
svcSet PairingDone
PairingDone -> throwError $ "already done"
pairingReject :: forall a m proxy. (PairingResult a, MonadIO m, MonadError String m) => proxy a -> Peer -> m ()
pairingReject _ peer = runPeerService @(PairingService a) peer $ do
svcGet >>= \case
NoPairing -> throwError $ "none in progress"
PairingDone -> throwError $ "already done"
_ -> reject PairingUserRejected
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