check group ID in other cases

src/Simplex/Chat/Library/Commands.hs

@@ -3899,6 +3899,10 @@ processChatCommand vr nm = \case
                 let FixedLinkData {linkConnReq = cReq, linkEntityId} = fd
                     linkInfo = GroupShortLinkInfo {direct, groupRelays = relays, sharedGroupId = B64UrlByteString <$> linkEntityId}
                 groupSLinkData_ <- liftIO $ decodeLinkUserData cData
+                -- Validate link entity ID matches group profile's sharedGroupId
+                forM_ groupSLinkData_ $ \GroupShortLinkData {groupProfile = GroupProfile {sharedGroupId}} ->
+                  unless ((B64UrlByteString <$> linkEntityId) == sharedGroupId) $
+                    throwChatError CEInvalidConnReq
                 plan <- groupJoinRequestPlan user cReq (Just linkInfo) groupSLinkData_
                 pure (con cReq, plan)
             where

src/Simplex/Chat/Library/Subscriber.hs

@@ -746,8 +746,10 @@ processAgentMessageConn vr user@User {userId} corrId agentConnId agentMessage =
               _ -> messageError "CONF from invited member must have x.grp.acpt"
           GCHostMember ->
             case chatMsgEvent of
-              XGrpLinkInv glInv -> do
+              XGrpLinkInv glInv@GroupLinkInvitation {groupProfile = GroupProfile {sharedGroupId = rcvGId}} -> do
                 -- XGrpLinkInv here means we are connecting via prepared group, and we have to update user and host member records
+                let GroupInfo {groupProfile = GroupProfile {sharedGroupId = curGId}} = gInfo
+                when (rcvGId /= curGId) $ messageError "x.grp.link.inv: sharedGroupId mismatch"
                 (gInfo', m') <- withStore $ \db -> updatePreparedUserAndHostMembersInvited db vr user gInfo m glInv
                 -- [incognito] send saved profile
                 incognitoProfile <- forM customUserProfileId $ \pId -> withStore (\db -> getProfileById db userId pId)
@@ -3611,7 +3613,9 @@ runRelayRequestWorker a Worker {doWork} = do
               (FixedLinkData {linkEntityId, rootKey}, cData@(ContactLinkData _ UserContactData {owners})) <- getShortLinkConnReq NRMBackground user reqGroupLink
               liftIO (decodeLinkUserData cData) >>= \case
                 Nothing -> throwChatError $ CEException "getLinkDataCreateRelayLink: no group link data"
-                Just GroupShortLinkData {groupProfile = gp} -> do
+                Just GroupShortLinkData {groupProfile = gp@GroupProfile {sharedGroupId}} -> do
+                  unless ((B64UrlByteString <$> linkEntityId) == sharedGroupId) $
+                    throwChatError $ CEException "getLinkDataCreateRelayLink: linkEntityId does not match profile sharedGroupId"
                   validateGroupProfile gp
                   gVar <- asks random
                   (_, memberPrivKey) <- liftIO $ atomically $ C.generateKeyPair gVar