[jira] [Created] (SSHD-851) Last chunk of data lost into local port forwarding channel

["Roberto Deandrea (JIRA)" <ji...@apache.org>]

Roberto Deandrea created SSHD-851:
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             Summary: Last chunk of data lost into local port forwarding channel
                 Key: SSHD-851
                 URL: https://issues.apache.org/jira/browse/SSHD-851
             Project: MINA SSHD
          Issue Type: Bug
    Affects Versions: 2.1.1
            Reporter: Roberto Deandrea
         Attachments: sshd.agent.trace

Hi Lyor,

I found another problem transferring data through a local port forwarding channel.

It seems that the problem is located into Apache SSHD server code according to me.

All the data are transferred from the originating client to the Apache SSH client and then go to the SSHD server through a local port forwarding channel.

When the client stops sending data, and the channel is being closed,  the SSHD server fail to send the last chunk of data to the target destination.

In the attached trace file the problem is isolated as the following:

*local port forwarding channel : [id=732 recipient=732]*

*Nio2Session[local=/0:0:0:0:0:0:0:0:50047, remote=/192.168.2.107:62284 session against target server*

Looking through the traces I see that when the local port forwarding channel is closed, the Nio2Session against the target server is closed gracefully, but instead of waiting to complete pending socket writes to the target server the Nio2Session is then closed immediately causing write failures.

In the traces I see:

2018-10-16 16:20:19,167 DEBUG [xdmzdriverssh@/192.168.10.34:55335]]-thread-1] [AbstractCloseable.close] close(Nio2Session[local=/0:0:0:0:0:0:0:0:50047, remote=/192.168.2.107:62284]) Closing gracefully
2018-10-16 16:20:19,167 DEBUG [xdmzdriverssh@/192.168.10.34:55335]]-thread-2] [AbstractCloseable.close] close(org.apache.sshd.common.io.nio2.Nio2Connector@77fcff14) Closing immediately^M
2018-10-16 16:20:19,167 DEBUG [xdmzdriverssh@/192.168.10.34:55335]]-thread-2] [AbstractCloseable.close] close(Nio2Session[local=/0:0:0:0:0:0:0:0:50047, remote=/192.168.2.107:62284]) Closing immediately

After that  I see:

2018-10-16 16:20:19,167 DEBUG [xdmzdriverssh@/192.168.10.34:55335]]-thread-2] [Nio2Session.doCloseImmediately] doCloseImmediately(Nio2Session[local=/0:0:0:0:0:0:0:0:50047, remote=/192.168.2.107:62284]) signal write abort for future=Nio2DefaultIoWriteFuture[id=/192.168.2.107:62284][value=null]
2018-10-16 16:20:19,167 DEBUG [xdmzdriverssh@/192.168.10.34:55335]]-thread-2] [TcpipServerChannel.handleWriteDataFailure] handleWriteDataFailure(TcpipServerChannel[id=732, recipient=732]-ServerSessionImpl[aixdmzdriverssh@/192.168.10.34:55335])[SSH_MSG_CHANNEL_DATA] failed (WriteAbortedException) to write len=16384: Write request aborted due to immediate session close

 

These errors are repeated multiple times.

The sum of bytes not written are equal to the chunk of data missing ad the target server.

Can you troubleshoot this problem?

Let me know if you need more info.

 

Cheers

Roberto

 



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