issue with Sbridge ssh sftp client disconnect on sbridge server

[tcaduto12068]

I'm having a error popup when I connect to my sbridge server using a sbridge client:
(using latest version of sbridge on Lazarus 2.06)

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12/18/2019 01:30:00 PM:[Error] SSH Client(127.0.0.1:50920) ERROR for user:testuser:Error on data reading from the connection:
An established connection was aborted by the software in your host machine..

This only happens with the sbridge sftp and ssh client, if I use filezilla etc no error.

Is this the proper way to use the devart SFTP Client?

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sftpmod.SSH.HostName:=maindatamod.FTPAddress;
          sftpmod.SSH.Port:=10022;
          sftpmod.SSH.User:=username;
          sftpmod.SSH.Password:=PassWord;
          sftpmod.SSH.Connect;
          if sftpmod.SSH.Connected then
              begin
                   if not sftpmod.SFTP.Active then
                      sftpmod.SFTP.Initialize;
                   sftpmod.SFTP.UploadFromStream(astream,'/'+testfilename,true);
                   MessageDlg(self,'Success','Test file uploaded successfully.',mtInformation,[mbok],0);
                   sftpmod.sftp.Disconnect;
                   sftpmod.SSH.Connected:=false; 
       end;  

[tcaduto12068]

Well no idea why this works but it gets rid of the error on the server:

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                   sftpmod.sftp.Disconnect;
                   sleep(500);
                   sftpmod.SSH.Disconnect;
                   sleep(500); 

Anyone have any idea why I have to add sleeps ?

The error on the Sbridge server is occurring in the OnClientError Event.

It's almost as if there is some kind of threading issue (missing a wait maybe?)with the SFTPClient component. I can go as low as 200ms in the sleeps before the error happens again.
I tried a bunch of other SFTP clients and the error does not happen with any of them, just the SecureBridge client component.
Any hints on if I am not using the SFTP and SSH client components properly?

[ViktorV]

Please try to use night build of SecureBridge which we sent you and inform us about the results.

[tcaduto12068]

ok, I will check it out and report back :-) Thanks :-)

[tcaduto12068]

No change with the nightly build:

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12/20/2019 08:13:37 AM:[Error] SSH Client(127.0.0.1:59332) ERROR for user:testuser:Error on data reading from the connection:
An established connection was aborted by the software in your host machine..
Socket Error Code: 10053($2745)

This is the disconnect code I used on the client side:

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if (SSH.Connected) then
                begin
                     SFTP.Disconnect;
                     //sleep(100);
                     SSH.Disconnect;
                    // sleep(100);
                end;
                 

I can get that same error with Filezilla or other client if I kill it from the task manager. It's like the client component is not waiting for the response from the server when shutting down.

[tcaduto12068]

Update, I also ran everything on Linux and the error behavior is different and worse on Linux (Manjaro latest)

What happens on Linux is I connect with the client component do a directory listing and that works fine, then I let the client sit and it disconnects by itself on exactly the 15 second timeout defined in the client components properties with this error



https://photos.app.goo.gl/hFpgz2WyaWSBvNzC6

As on windows the server is working perfectly with other clients like the Linux version of FileZilla, ssh command line etc.

[Dimon]

Thank you for the information.
A distinctive feature of SSH protocol is that it doesn't send any special package to the server when closing the connection -- SSH simply closes the physical connection. This error suggests that the connection was closed on the SSH client side. We'll change the behavior of the SSH server to prevent the associated event for this error.

[tcaduto12068]

The secure bridge client did not exhibit this behavior a few versions ago and other clients don't cause the error on the secure bridge server, it seems to be a issue with the sb client. I started to notice this behavior maybe around April 2019.

[tcaduto12068]

I just installed the latest version you guys released on Friday and the issue is gone on Windows.
Will try on Linux in the morning. Thanks :-)

[ViktorV]

When you get any results concerning this question, please let us know.