diff options
Diffstat (limited to 'Assistant')
| -rw-r--r-- | Assistant/Threads/PairListener.hs | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/Assistant/Threads/PairListener.hs b/Assistant/Threads/PairListener.hs index 09fd9513d..93eef65ba 100644 --- a/Assistant/Threads/PairListener.hs +++ b/Assistant/Threads/PairListener.hs @@ -22,6 +22,7 @@ import Utility.Tense import Network.Multicast import Network.Socket import qualified Data.Text as T +import Data.Char thisThread :: ThreadName thisThread = "PairListener" @@ -36,16 +37,18 @@ pairListenerThread st dstatus scanremotes urlrenderer = thread $ withSocketsDo $ go sock cache = getmsg sock [] >>= \msg -> case readish msg of Nothing -> go sock cache Just m -> do + sane <- checkSane msg (pip, verified) <- verificationCheck m =<< (pairingInProgress <$> getDaemonStatus dstatus) - case pairMsgStage m of - PairReq -> do + case (sane, pairMsgStage m) of + (False, _) -> go sock cache + (_, PairReq) -> do pairReqReceived verified dstatus urlrenderer m go sock $ invalidateCache m cache - PairAck -> do + (_, PairAck) -> do pairAckReceived verified pip st dstatus scanremotes m cache >>= go sock - PairDone -> do + (_, PairDone) -> do pairDoneReceived verified pip st dstatus scanremotes m go sock cache @@ -53,7 +56,8 @@ pairListenerThread st dstatus scanremotes urlrenderer = thread $ withSocketsDo $ - check its UUID against the UUID we have stored. If - they're the same, someone is sending bogus messages, - which could be an attempt to brute force the shared - - secret. -} + - secret. + -} verificationCheck m (Just pip) = do let verified = verifiedPairMsg m pip let sameuuid = pairUUID (inProgressPairData pip) == pairUUID (pairMsgData $ m) @@ -65,6 +69,16 @@ pairListenerThread st dstatus scanremotes urlrenderer = thread $ withSocketsDo $ return (Nothing, False) else return (Just pip, verified && sameuuid) verificationCheck _ Nothing = return (Nothing, False) + + {- Various sanity checks on the content of the message. -} + checkSane msg + {- Control characters could be used in a + - console poisoning attack. -} + | any isControl msg || any (`elem` "\r\n") msg = do + runThreadState st $ + warning "illegal control characters in pairing message; ignoring" + return False + | otherwise = return True {- PairReqs invalidate the cache of recently finished pairings. - This is so that, if a new pairing is started with the |