core: prohibit SMP file handshake for XFTP files on sender side, except for images and voice messages (#2201)

src/Simplex/Chat.hs

@@ -3380,6 +3380,8 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
     xFileAcptInv ct sharedMsgId fileConnReq_ fName msgMeta = do
       checkIntegrityCreateItem (CDDirectRcv ct) msgMeta
       fileId <- withStore $ \db -> getDirectFileIdBySharedMsgId db user ct sharedMsgId
+      (AChatItem _ _ _ ci) <- withStore $ \db -> getChatItemByFileId db user fileId
+      assertSMPAcceptNotProhibited ci
       ft@FileTransferMeta {fileName, fileSize, fileInline, cancelled} <- withStore (\db -> getFileTransferMeta db user fileId)
       -- [async agent commands] no continuation needed, but command should be asynchronous for stability
       if fName == fileName
@@ -3391,9 +3393,9 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
           -- receiving inline
           _ -> do
             event <- withStore $ \db -> do
-              ci <- updateDirectCIFileStatus db user fileId $ CIFSSndTransfer 0 1
+              ci' <- updateDirectCIFileStatus db user fileId $ CIFSSndTransfer 0 1
               sft <- liftIO $ createSndDirectInlineFT db ct ft
-              pure $ CRSndFileStart user ci sft
+              pure $ CRSndFileStart user ci' sft
             toView event
             ifM
               (allowSendInline fileSize fileInline)
@@ -3401,6 +3403,17 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
               (messageError "x.file.acpt.inv: fileSize is bigger than allowed to send inline")
         else messageError "x.file.acpt.inv: fileName is different from expected"
 
+    assertSMPAcceptNotProhibited :: ChatItem c d -> m ()
+    assertSMPAcceptNotProhibited ChatItem {file = Just CIFile {fileId, fileProtocol}, content}
+      | fileProtocol == FPXFTP && not (imageOrVoice content) = throwChatError $ CEFallbackToSMPProhibited fileId
+      | otherwise = pure ()
+      where
+        imageOrVoice :: CIContent d -> Bool
+        imageOrVoice (CISndMsgContent (MCImage _ _)) = True
+        imageOrVoice (CISndMsgContent (MCVoice _ _)) = True
+        imageOrVoice _ = False
+    assertSMPAcceptNotProhibited _ = pure ()
+
     checkSndInlineFTComplete :: Connection -> AgentMsgId -> m ()
     checkSndInlineFTComplete conn agentMsgId = do
       sft_ <- withStore' $ \db -> getSndFTViaMsgDelivery db user conn agentMsgId
@@ -3463,6 +3476,8 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
     xFileAcptInvGroup g@GroupInfo {groupId} m@GroupMember {activeConn} sharedMsgId fileConnReq_ fName msgMeta = do
       checkIntegrityCreateItem (CDGroupRcv g m) msgMeta
       fileId <- withStore $ \db -> getGroupFileIdBySharedMsgId db userId groupId sharedMsgId
+      (AChatItem _ _ _ ci) <- withStore $ \db -> getChatItemByFileId db user fileId
+      assertSMPAcceptNotProhibited ci
       -- TODO check that it's not already accepted
       ft@FileTransferMeta {fileName, fileSize, fileInline, cancelled} <- withStore (\db -> getFileTransferMeta db user fileId)
       if fName == fileName
@@ -3475,9 +3490,9 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
           (_, Just conn) -> do
             -- receiving inline
             event <- withStore $ \db -> do
-              ci <- updateDirectCIFileStatus db user fileId $ CIFSSndTransfer 0 1
+              ci' <- updateDirectCIFileStatus db user fileId $ CIFSSndTransfer 0 1
               sft <- liftIO $ createSndGroupInlineFT db m conn ft
-              pure $ CRSndFileStart user ci sft
+              pure $ CRSndFileStart user ci' sft
             toView event
             ifM
               (allowSendInline fileSize fileInline)

src/Simplex/Chat/Controller.hs

@@ -795,6 +795,7 @@ data ChatErrorType
   | CEFileNotReceived {fileId :: FileTransferId}
   | CEXFTPRcvFile {fileId :: FileTransferId, agentRcvFileId :: AgentRcvFileId, agentError :: AgentErrorType}
   | CEXFTPSndFile {fileId :: FileTransferId, agentSndFileId :: AgentSndFileId, agentError :: AgentErrorType}
+  | CEFallbackToSMPProhibited {fileId :: FileTransferId}
   | CEInlineFileProhibited {fileId :: FileTransferId}
   | CEInvalidQuote
   | CEInvalidChatItemUpdate

src/Simplex/Chat/View.hs

@@ -1305,6 +1305,7 @@ viewChatError logLevel = \case
     CEFileNotReceived fileId -> ["file " <> sShow fileId <> " not received"]
     CEXFTPRcvFile fileId aFileId e -> ["error receiving XFTP file " <> sShow fileId <> ", agent file id " <> sShow aFileId <> ": " <> sShow e | logLevel == CLLError]
     CEXFTPSndFile fileId aFileId e -> ["error sending XFTP file " <> sShow fileId <> ", agent file id " <> sShow aFileId <> ": " <> sShow e | logLevel == CLLError]
+    CEFallbackToSMPProhibited fileId -> ["recipient tried to accept file " <> sShow fileId <> " via old protocol, prohibited"]
     CEInlineFileProhibited _ -> ["A small file sent without acceptance - you can enable receiving such files with -f option."]
     CEInvalidQuote -> ["cannot reply to this message"]
     CEInvalidChatItemUpdate -> ["cannot update this item"]