core: file invitation size check (#7069)

* core: file invitation size check

* comment

* comment

src/Simplex/Chat/Library/Internal.hs

@@ -700,7 +700,7 @@ acceptFileReceive user@User {userId} RcvFileTransfer {fileId, xftpRcvFile, fileI
         ci <- xftpAcceptRcvFT db cxt user fileId filePath userApproved
         rfd <- getRcvFileDescrByRcvFileId db fileId
         pure (ci, rfd)
-      receiveViaCompleteFD user fileId rfd userApproved cryptoArgs
+      receiveViaCompleteFD user fileId rfd fileSize userApproved cryptoArgs
       pure ci
     (Nothing, Just _fileConnReq) -> throwChatError $ CEException "accepting file via a separate connection is deprecated"
     -- group & direct file protocol
@@ -742,10 +742,17 @@ acceptFileReceive user@User {userId} RcvFileTransfer {fileId, xftpRcvFile, fileI
                 || (rcvInline_ == Just True && fileSize <= fileChunkSize * offerChunks)
              )
 
-receiveViaCompleteFD :: User -> FileTransferId -> RcvFileDescr -> Bool -> Maybe CryptoFileArgs -> CM ()
-receiveViaCompleteFD user fileId RcvFileDescr {fileDescrText, fileDescrComplete} userApprovedRelays cfArgs =
+receiveViaCompleteFD :: User -> FileTransferId -> RcvFileDescr -> Integer -> Bool -> Maybe CryptoFileArgs -> CM ()
+receiveViaCompleteFD user fileId RcvFileDescr {fileDescrText, fileDescrComplete} expectedFileSize userApprovedRelays cfArgs =
   when fileDescrComplete $ do
     rd <- parseFileDescription fileDescrText
+    let FD.ValidFileDescription FD.FileDescription {size = FD.FileSize encSize, redirect} = rd
+        redirectSize = maybe 0 (\FD.RedirectFileInfo {size = FD.FileSize s} -> toInteger s) redirect
+        -- for a redirect, encSize is the description blob and redirectSize the final file; take the larger
+        rcvSize = max (toInteger encSize) redirectSize
+        -- 10 MB margin: encryption and chunk-size rounding make the transfer larger than the advertised size
+        maxRcvSize = min expectedFileSize (toInteger FD.maxFileSizeHard) + toInteger (FD.mb 10 :: Int64)
+    when (rcvSize > maxRcvSize) $ throwChatError $ CEFileRcvChunk "declared file size exceeds the file invitation size"
     if userApprovedRelays
       then receive' rd True
       else do

src/Simplex/Chat/Library/Subscriber.hs

@@ -1894,7 +1894,7 @@ processAgentMessageConn cxt user@User {userId} corrId agentConnId agentMessage =
     processFDMessage fileId aci fileDescr = do
       ft <- withStore $ \db -> getRcvFileTransfer db user fileId
       unless (rcvFileCompleteOrCancelled ft) $ do
-        (rfd@RcvFileDescr {fileDescrComplete}, ft'@RcvFileTransfer {fileStatus, xftpRcvFile, cryptoArgs}) <- withStore $ \db -> do
+        (rfd@RcvFileDescr {fileDescrComplete}, ft'@RcvFileTransfer {fileStatus, xftpRcvFile, cryptoArgs, fileInvitation = FileInvitation {fileSize}}) <- withStore $ \db -> do
           rfd <- appendRcvFD db userId fileId fileDescr
           -- reading second time in the same transaction as appending description
           -- to prevent race condition with accept
@@ -1902,15 +1902,15 @@ processAgentMessageConn cxt user@User {userId} corrId agentConnId agentMessage =
           pure (rfd, ft')
         when fileDescrComplete $ toView $ CEvtRcvFileDescrReady user aci ft' rfd
         case (fileStatus, xftpRcvFile) of
-          (RFSAccepted _, Just XFTPRcvFile {userApprovedRelays}) -> receiveViaCompleteFD user fileId rfd userApprovedRelays cryptoArgs
+          (RFSAccepted _, Just XFTPRcvFile {userApprovedRelays}) -> receiveViaCompleteFD user fileId rfd fileSize userApprovedRelays cryptoArgs
           _ -> pure ()
 
     processFileInvitation :: Maybe FileInvitation -> MsgContent -> (DB.Connection -> FileInvitation -> Maybe InlineFileMode -> Integer -> ExceptT StoreError IO RcvFileTransfer) -> CM (Maybe (RcvFileTransfer, CIFile 'MDRcv))
-    processFileInvitation fInv_ mc createRcvFT = forM fInv_ $ \fInv' -> do
+    processFileInvitation fInv_ mc createRcvFT = forM fInv_ $ \fInv -> do
       ChatConfig {fileChunkSize} <- asks config
-      let fInv@FileInvitation {fileName, fileSize} = mkValidFileInvitation fInv'
-      inline <- receiveInlineMode fInv (Just mc) fileChunkSize
-      ft@RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvFT db fInv inline fileChunkSize
+      fInv'@FileInvitation {fileName, fileSize} <- validateFileInvitation fInv
+      inline <- receiveInlineMode fInv' (Just mc) fileChunkSize
+      ft@RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvFT db fInv' inline fileChunkSize
       let fileProtocol = if isJust xftpRcvFile then FPXFTP else FPSMP
       (filePath, fileStatus, ft') <- case inline of
         Just IFMSent -> do
@@ -1927,6 +1927,11 @@ processAgentMessageConn cxt user@User {userId} corrId agentConnId agentMessage =
     mkValidFileInvitation :: FileInvitation -> FileInvitation
     mkValidFileInvitation fInv@FileInvitation {fileName} = fInv {fileName = FP.makeValid $ FP.takeFileName fileName}
 
+    validateFileInvitation :: FileInvitation -> CM FileInvitation
+    validateFileInvitation fInv@FileInvitation {fileName, fileSize}
+      | fileSize > 0 = pure $ mkValidFileInvitation fInv
+      | otherwise = throwChatError $ CEFileSize fileName
+
     messageUpdate :: Contact -> SharedMsgId -> MsgContent -> RcvMessage -> MsgMeta -> Maybe Int -> Maybe Bool -> CM ()
     messageUpdate ct@Contact {contactId} sharedMsgId mc msg@RcvMessage {msgId} msgMeta ttl live_ = do
       updateRcvChatItem `catchCINotFound` \_ -> do
@@ -2332,11 +2337,11 @@ processAgentMessageConn cxt user@User {userId} corrId agentConnId agentMessage =
 
     -- TODO remove once XFile is discontinued
     processFileInvitation' :: Contact -> FileInvitation -> RcvMessage -> MsgMeta -> CM ()
-    processFileInvitation' ct fInv' msg@RcvMessage {sharedMsgId_} msgMeta = do
+    processFileInvitation' ct fInv msg@RcvMessage {sharedMsgId_} msgMeta = do
       ChatConfig {fileChunkSize} <- asks config
-      let fInv@FileInvitation {fileName, fileSize} = mkValidFileInvitation fInv'
-      inline <- receiveInlineMode fInv Nothing fileChunkSize
-      RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvFileTransfer db userId ct fInv inline fileChunkSize
+      fInv'@FileInvitation {fileName, fileSize} <- validateFileInvitation fInv
+      inline <- receiveInlineMode fInv' Nothing fileChunkSize
+      RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvFileTransfer db userId ct fInv' inline fileChunkSize
       let fileProtocol = if isJust xftpRcvFile then FPXFTP else FPSMP
           ciFile = Just $ CIFile {fileId, fileName, fileSize, fileSource = Nothing, fileStatus = CIFSRcvInvitation, fileProtocol}
           content = ciContentNoParse $ CIRcvMsgContent $ MCFile ""
@@ -2347,10 +2352,11 @@ processAgentMessageConn cxt user@User {userId} corrId agentConnId agentMessage =
 
     -- TODO remove once XFile is discontinued
     processGroupFileInvitation' :: GroupInfo -> GroupMember -> FileInvitation -> RcvMessage -> UTCTime -> CM ()
-    processGroupFileInvitation' gInfo m fInv@FileInvitation {fileName, fileSize} msg@RcvMessage {sharedMsgId_} brokerTs = do
+    processGroupFileInvitation' gInfo m fInv msg@RcvMessage {sharedMsgId_} brokerTs = do
       ChatConfig {fileChunkSize} <- asks config
-      inline <- receiveInlineMode fInv Nothing fileChunkSize
-      RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvGroupFileTransfer db userId gInfo (Just m) fInv inline fileChunkSize
+      fInv'@FileInvitation {fileName, fileSize} <- validateFileInvitation fInv
+      inline <- receiveInlineMode fInv' Nothing fileChunkSize
+      RcvFileTransfer {fileId, xftpRcvFile} <- withStore $ \db -> createRcvGroupFileTransfer db userId gInfo (Just m) fInv' inline fileChunkSize
       let fileProtocol = if isJust xftpRcvFile then FPXFTP else FPSMP
           ciFile = Just $ CIFile {fileId, fileName, fileSize, fileSource = Nothing, fileStatus = CIFSRcvInvitation, fileProtocol}
           content = ciContentNoParse $ CIRcvMsgContent $ MCFile ""