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refactor request sender ID spoof check to suit k-choices

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- mostly refactored the checks into its own function
- now additionally check the vserver number limit
- refactoring to pass that limit to the checking function invocations
- closes #74
This commit is contained in:
Trolli Schmittlauch 2020-09-29 02:59:42 +02:00
parent b2b4fe3dd8
commit bb0fb0919a
3 changed files with 28 additions and 20 deletions
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33
src/Hash2Pub/DHTProtocol.hs
View file

@ -66,6 +66,7 @@ import Data.Maybe (fromJust, fromMaybe, isJust,
isNothing, mapMaybe, maybe)
import qualified Data.Set as Set
import Data.Time.Clock.POSIX
import Data.Word (Word8)
import Network.Socket hiding (recv, recvFrom, send,
sendTo)
import Network.Socket.ByteString
@ -93,6 +94,7 @@ import Hash2Pub.FediChordTypes (CacheEntry (..),
getKeyID, localCompare,
rMapFromList, rMapLookupPred,
rMapLookupSucc,
hasValidNodeId,
remainingLoadTarget,
setPredecessors, setSuccessors)
import Hash2Pub.ProtocolTypes
@ -267,12 +269,13 @@ extractFirstPayload msgSet = foldr' (\msg plAcc ->
-- | Dispatch incoming requests to the dedicated handling and response function, and enqueue
-- the response to be sent.
handleIncomingRequest :: Service s (RealNodeSTM s)
=> LocalNodeStateSTM s -- ^ the handling node
=> Word8 -- ^ maximum number of vservers, because of decision to @dropSpoofedIDs@ in here and not already in @fediMessageHandler@
-> LocalNodeStateSTM s -- ^ the handling node
-> TQueue (BS.ByteString, SockAddr) -- ^ send queue
-> Set.Set FediChordMessage -- ^ all parts of the request to handle
-> SockAddr -- ^ source address of the request
-> IO ()
handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do
handleIncomingRequest vsLimit nsSTM sendQ msgSet sourceAddr = do
ns <- readTVarIO nsSTM
-- add nodestate to cache
now <- getPOSIXTime
@ -287,12 +290,12 @@ handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do
)
=<< (case action aPart of
Ping -> Just <$> respondPing nsSTM msgSet
Join -> dropSpoofedIDs sourceIP nsSTM msgSet respondJoin
Join -> dropSpoofedIDs vsLimit sourceIP nsSTM msgSet respondJoin
-- ToDo: figure out what happens if not joined
QueryID -> Just <$> respondQueryID nsSTM msgSet
-- only when joined
Leave -> if vsIsJoined ns then dropSpoofedIDs sourceIP nsSTM msgSet respondLeave else pure Nothing
Stabilise -> if vsIsJoined ns then dropSpoofedIDs sourceIP nsSTM msgSet respondStabilise else pure Nothing
Leave -> if vsIsJoined ns then dropSpoofedIDs vsLimit sourceIP nsSTM msgSet respondLeave else pure Nothing
Stabilise -> if vsIsJoined ns then dropSpoofedIDs vsLimit sourceIP nsSTM msgSet respondStabilise else pure Nothing
QueryLoad -> if vsIsJoined ns then Just <$> respondQueryLoad nsSTM msgSet else pure Nothing
)
-- for single part request, response starts with part number 1. For multipart requests, response starts with part number n+1.
@ -303,19 +306,18 @@ handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do
-- | Filter out requests with spoofed node IDs by recomputing the ID using
-- the sender IP.
-- For valid (non-spoofed) sender IDs, the passed responder function is invoked.
dropSpoofedIDs :: HostAddress6 -- msg source address
dropSpoofedIDs :: Word8 -- ^ maximum number of vservers per node
-> HostAddress6 -- ^ msg source address
-> LocalNodeStateSTM s
-> Set.Set FediChordMessage -- message parts of the request
-> (LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString)) -- reponder function to be invoked for valid requests
-> Set.Set FediChordMessage -- ^ message parts of the request
-> (LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString)) -- ^ reponder function to be invoked for valid requests
-> IO (Maybe (Map.Map Integer BS.ByteString))
dropSpoofedIDs addr nsSTM' msgSet' responder =
dropSpoofedIDs limVs addr nsSTM' msgSet' responder =
let
aRequestPart = Set.elemAt 0 msgSet
senderNs = sender aRequestPart
givenSenderID = getNid senderNs
recomputedID = genNodeID addr (getDomain senderNs) (getVServerID senderNs)
in
if recomputedID == givenSenderID
if hasValidNodeId limVs senderNs addr
then Just <$> responder nsSTM' msgSet'
else pure Nothing
@ -779,10 +781,9 @@ requestPing ns target = do
-- recompute ID for each received node and mark as verified in cache
now <- getPOSIXTime
forM_ responseVss (\vs ->
let recomputedID = genNodeID peerAddr (getDomain vs) (getVServerID vs)
in if recomputedID == getNid vs
then atomically $ writeTQueue (cacheWriteQueue ns) $ addNodeAsVerifiedPure now vs
else pure ()
if hasValidNodeId (confKChoicesMaxVS nodeConf) vs peerAddr
then atomically $ writeTQueue (cacheWriteQueue ns) $ addNodeAsVerifiedPure now vs
else pure ()
)
pure $ if null responseVss
then Left "no active vServer IDs returned, ignoring node"

10
src/Hash2Pub/FediChord.hs
View file

@ -901,6 +901,12 @@ fediMessageHandler sendQ recvQ nodeSTM = do
-- both of them fail
concurrently_ (requestMapPurge (confResponsePurgeAge nodeConf) requestMap) $ forever $ do
node <- readTVarIO nodeSTM
-- Messages from invalid (spoofed) sender IDs could already be dropped here
-- or in @dispatchVS@. But as the checking on each possible ID causes an
-- overhead, it is only done for critical operations and the case
-- differentiation is done in @handleIncomingRequest@. Thus the vserver
-- number limit, required for this check, needs to be passed to that function.
let handlerFunc = handleIncomingRequest $ confKChoicesMaxVS nodeConf
-- wait for incoming messages
(rawMsg, sourceAddr) <- atomically $ readTQueue recvQ
let aMsg = deserialiseMessage rawMsg
@ -915,7 +921,7 @@ fediMessageHandler sendQ recvQ nodeSTM = do
Nothing -> pure ()
-- if not a multipart message, handle immediately. Response is at the same time an ACK
Just nsSTM | part aRequest == 1 && isFinalPart aRequest ->
forkIO (handleIncomingRequest nsSTM sendQ (Set.singleton aRequest) sourceAddr) >> pure ()
forkIO (handlerFunc nsSTM sendQ (Set.singleton aRequest) sourceAddr) >> pure ()
-- otherwise collect all message parts first before handling the whole request
Just nsSTM | otherwise -> do
now <- getPOSIXTime
@ -942,7 +948,7 @@ fediMessageHandler sendQ recvQ nodeSTM = do
(RequestMapEntry theseParts mayMaxParts _) = fromJust $ Map.lookup thisKey newMapState
numParts = Set.size theseParts
if maybe False (numParts ==) (fromIntegral <$> mayMaxParts)
then forkIO (handleIncomingRequest nsSTM sendQ theseParts sourceAddr) >> pure()
then forkIO (handlerFunc nsSTM sendQ theseParts sourceAddr) >> pure()
else pure()
-- Responses should never arrive on the main server port, as they are always
-- responses to requests sent from dedicated sockets on another port

5
src/Hash2Pub/FediChordTypes.hs
View file

@ -57,6 +57,7 @@ module Hash2Pub.FediChordTypes
, localCompare
, genNodeID
, genNodeIDBS
, hasValidNodeId
, genKeyID
, genKeyIDBS
, byteStringToUInteger
@ -392,8 +393,8 @@ genNodeID :: HostAddress6 -- ^a node's IPv6 address
genNodeID ip nodeDomain vs = NodeID . byteStringToUInteger $ genNodeIDBS ip nodeDomain vs
isValidIdForNode :: Word8 -> RemoteNodeState -> HostAddress6 -> Bool
isValidIdForNode numVs rns addr = getNid rns `elem` [genNodeID addr (getDomain rns) v | v <- [0..(numVs-1)] ]
hasValidNodeId :: Word8 -> RemoteNodeState -> HostAddress6 -> Bool
hasValidNodeId numVs rns addr = getVServerID rns < numVs && getNid rns == genNodeID addr (getDomain rns) (getVServerID rns)
-- | generates a 256 bit long key identifier, represented as ByteString, for looking up its data on the DHT