d670413 · skrepka · git.iko.soy

git.iko.soy/skrepka

Fix safeCompare length leak, offline gossip trust bypass, hop-0 injection, federation retry, and per-recipient message cap

d670413iko7 months ago

server.knot+25−12

compare with master

unifiedsplit

@@ -18,6 +18,7 @@ maxMessageIds = 100

18maxGossipEvents = 100

19maxPollEvents = 50

20maxPresenceEntries = 10000

21+maxMessagesPerRecipient = 500

21clockSkewTolerance = 5000 -- 5 seconds tolerance for clock skew between federated servers

22clockSkewTolerance = 5000 -- 5 seconds tolerance for clock skew between federated servers

23-- ============================================

24-- ============================================

@@ -138,8 +139,8 @@ verifyFederationAuth = \authorization ->

138clampTtl = \ttl -> if ttl < 1 then 1 else if ttl > maxPresenceTtl then maxPresenceTtl else ttl

139clampTtl = \ttl -> if ttl < 1 then 1 else if ttl > maxPresenceTtl then maxPresenceTtl else ttl

139

140

140safeCompareLoop = \s1 s2 result ->

141safeCompareLoop = \s1 s2 result ->

141− if s1 == "" && s2 == ""

142+ if s2 == ""

142− then result

143+ then result + (if s1 == "" then 0 else 1)

143 else safeCompareLoop (drop 1 s1) (drop 1 s2) (result + (if take 1 s1 == take 1 s2 then 0 else 1))

144 else safeCompareLoop (drop 1 s1) (drop 1 s2) (result + (if take 1 s1 == take 1 s2 then 0 else 1))

144

145

145safeCompare = \a b -> safeCompareLoop a b 0 == 0

146safeCompare = \a b -> safeCompareLoop a b 0 == 0

@@ -155,9 +156,7 @@ sendToEach = \servers action ->

155 else do

156 else do

156 catch (action server) (\err -> do

157 catch (action server) (\err -> do

157 println ("federation: error reaching " ++ server ++ ": " ++ show err)

158 println ("federation: error reaching " ++ server ++ ": " ++ show err)

158− catch (action server) (\err2 -> do

159− println ("federation: retry failed for " ++ server ++ ": " ++ show err2)

160− yield {}))

159+ yield {})

161 sendToEach rest action

160 sendToEach rest action

162

161

163pruneExpired = \t -> do

162pruneExpired = \t -> do

@@ -381,13 +380,18 @@ serve = \req -> case req of

381 let session = lookupSession sessions (extractToken authorization) t

380 let session = lookupSession sessions (extractToken authorization) t

382 seqCounter <- *seqCounter

381 seqCounter <- *seqCounter

383 let seqTs = if t > seqCounter then t else seqCounter + 1

382 let seqTs = if t > seqCounter then t else seqCounter + 1

383+ let recipientMsgCount = count (do

384+ m <- messages

385+ where m.toKey == to

386+ where m.receivedAt >= t - messageMaxAge

387+ yield m)

384 let shouldInsert = case session of

388 let shouldInsert = case session of

385 Nothing {} -> False {}

389 Nothing {} -> False {}

386− Just {value: _} -> validInput

390+ Just {value: _} -> validInput && recipientMsgCount < maxMessagesPerRecipient

387 set *seqCounter = if shouldInsert then seqTs else seqCounter

391 set *seqCounter = if shouldInsert then seqTs else seqCounter

388 set *messages = case session of

392 set *messages = case session of

389 Nothing {} -> messages

393 Nothing {} -> messages

390− Just {value: s} -> if validInput

394+ Just {value: s} -> if validInput && recipientMsgCount < maxMessagesPerRecipient

391 then union messages

395 then union messages

392 [{messageId: msgId, toKey: to, fromKey: s.pubkey,

396 [{messageId: msgId, toKey: to, fromKey: s.pubkey,

393 encryptedBlob: encryptedBlob, timestamp: clampedTs, originServer: "", receivedAt: seqTs}]

397 encryptedBlob: encryptedBlob, timestamp: clampedTs, originServer: "", receivedAt: seqTs}]

@@ -514,7 +518,7 @@ serve = \req -> case req of

514 t <- now

518 t <- now

515 let authorized = verifyFederationAuth authorization

519 let authorized = verifyFederationAuth authorization

516 let cappedHops = if hopsRemaining > 5 then 5 else hopsRemaining

520 let cappedHops = if hopsRemaining > 5 then 5 else hopsRemaining

517− let validRequest = authorized && cappedHops >= 0 && not (fromServer == "") && not (fromServer == serverHost) && not (tooLong fromServer maxPubkeyLen) && not (containsBadUrlChar fromServer) && count events <= maxGossipEvents

521+ let validRequest = authorized && cappedHops >= 1 && not (fromServer == "") && not (fromServer == serverHost) && not (tooLong fromServer maxPubkeyLen) && not (containsBadUrlChar fromServer) && count events <= maxGossipEvents

518 let onlineEntries = do

522 let onlineEntries = do

519 e <- events

523 e <- events

520 where validRequest

524 where validRequest

@@ -580,6 +584,10 @@ serve = \req -> case req of

580 e <- deduped

584 e <- deduped

581 where e.server == fromServer || count (do p <- presence; where p.pubkey == e.pubkey; where p.server == e.server; yield p) > 0

585 where e.server == fromServer || count (do p <- presence; where p.pubkey == e.pubkey; where p.server == e.server; yield p) > 0

582 yield e

586 yield e

587+ let trustedOffline = do

588+ e <- offlineEntries

589+ where e.server == fromServer || count (do p <- presence; where p.pubkey == e.pubkey; where p.server == e.server; yield p) > 0

590+ yield e

583 let appliedOnline = do

591 let appliedOnline = do

584 e <- trustedDeduped

592 e <- trustedDeduped

585 where count (do

593 where count (do

@@ -614,7 +622,7 @@ serve = \req -> case req of

614 where p.pubkey == k.pubkey

622 where p.pubkey == k.pubkey

615 where p.server == k.server

623 where p.server == k.server

616 where count (do

624 where count (do

617− o <- offlineEntries

625+ o <- trustedOffline

618 where o.pubkey == k.pubkey

626 where o.pubkey == k.pubkey

619 where o.server == k.server

627 where o.server == k.server

620 where o.timestamp >= p.timestamp

628 where o.timestamp >= p.timestamp

@@ -627,7 +635,7 @@ serve = \req -> case req of

627 where p.pubkey == k.pubkey

635 where p.pubkey == k.pubkey

628 where p.server == k.server

636 where p.server == k.server

629 where count (do

637 where count (do

630− o <- offlineEntries

638+ o <- trustedOffline

631 where o.pubkey == k.pubkey

639 where o.pubkey == k.pubkey

632 where o.server == k.server

640 where o.server == k.server

633 where o.timestamp >= p.timestamp

641 where o.timestamp >= p.timestamp

@@ -658,7 +666,7 @@ serve = \req -> case req of

658 where p.pubkey == k.pubkey

666 where p.pubkey == k.pubkey

659 where p.server == k.server

667 where p.server == k.server

660 where count (do

668 where count (do

661− o <- offlineEntries

669+ o <- trustedOffline

662 where o.pubkey == k.pubkey

670 where o.pubkey == k.pubkey

663 where o.server == k.server

671 where o.server == k.server

664 where o.timestamp >= p.timestamp

672 where o.timestamp >= p.timestamp

@@ -739,13 +747,18 @@ serve = \req -> case req of

739 messages <- *messages

747 messages <- *messages

740 seqCounter <- *seqCounter

748 seqCounter <- *seqCounter

741 let seqTs = if t > seqCounter then t else seqCounter + 1

749 let seqTs = if t > seqCounter then t else seqCounter + 1

750+ let recipientMsgCount = count (do

751+ m <- messages

752+ where m.toKey == toKey

753+ where m.receivedAt >= t - messageMaxAge

754+ yield m)

742 let exists = count (do

755 let exists = count (do

743 m <- messages

756 m <- messages

744 where m.messageId == messageId

757 where m.messageId == messageId

745 where m.toKey == toKey

758 where m.toKey == toKey

746 where m.receivedAt >= t - messageMaxAge

759 where m.receivedAt >= t - messageMaxAge

747 yield m) > 0

760 yield m) > 0

748− let shouldInsert = authorized && validOrigin && validFields && not exists

761+ let shouldInsert = authorized && validOrigin && validFields && not exists && recipientMsgCount < maxMessagesPerRecipient

749 set *seqCounter = if shouldInsert then seqTs else seqCounter

762 set *seqCounter = if shouldInsert then seqTs else seqCounter

750 set *messages = if shouldInsert

763 set *messages = if shouldInsert

751 then union messages

764 then union messages