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Posted to dev@mina.apache.org by "Guillaume Nodet (JIRA)" <ji...@apache.org> on 2013/02/25 08:54:23 UTC
[jira] [Resolved] (SSHD-206) Race between SSH_MSG_CHANNEL_DATA and
SSH_MSG_CHANNEL_CLOSE in ChannelForwardedTcpip?
[ https://issues.apache.org/jira/browse/SSHD-206?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Guillaume Nodet resolved SSHD-206.
----------------------------------
Resolution: Fixed
https://git-wip-us.apache.org/repos/asf?p=mina-sshd.git;a=commit;h=866dca2a2cacce5d9ab98947606401d4c5ee4129
> Race between SSH_MSG_CHANNEL_DATA and SSH_MSG_CHANNEL_CLOSE in ChannelForwardedTcpip?
> -------------------------------------------------------------------------------------
>
> Key: SSHD-206
> URL: https://issues.apache.org/jira/browse/SSHD-206
> Project: MINA SSHD
> Issue Type: Bug
> Affects Versions: 0.8.0
> Reporter: Andrew C
> Assignee: Guillaume Nodet
> Fix For: 0.9.0
>
> Attachments: sshd-206.patch
>
>
> I've noticed what I believe is a race between ChannelForwardTcpip receiving SSH_MSG_CHANNEL_CLOSE from the remote end and it trying to send data to the remote end - it ends up sending data after it closed the channel :-(
> The sequence is roughly:
> - remote forwards tcp channel to local
> - remote and local chatter
> - remote gets a close and sends SSH_MSG_CHANNEL_CLOSE to local
> - local responds accordingly
> meanwhile, there's data intended for the remote end still sitting in a local queue somewhere and local proceeds to send it across the now dead channel
> - remote responds to the protocol violation with extreme prejudice killing the entire ssh session ;-)
> This is the local log (s/RelaySessionSshChannelRecipient/ChannelForwardTcpip/, they are essentially the same)
> [09:42:32.451] [NioProcessor-2] DEBUG org.apache.sshd.client.session.ClientSessionImpl - Received packet SSH_MSG_CHANNEL_CLOSE
> [09:42:32.451] [NioProcessor-2] DEBUG RelaySessionSshChannelRecipient - Received SSH_MSG_CHANNEL_CLOSE on channel 0
> [09:42:32.452] [NioProcessor-2] DEBUG RelaySessionSshChannelRecipient - Send SSH_MSG_CHANNEL_CLOSE on channel 0
> [09:42:32.453] [NioProcessor-2] DEBUG RelaySessionSshChannelRecipient - Closing channel 0 immediately
> [09:42:32.452] [NioProcessor-3] DEBUG RelaySessionSshChannelRecipient - Send SSH_MSG_CHANNEL_DATA on channel 0
> [09:42:32.460] [NioProcessor-2] DEBUG org.apache.sshd.client.session.ClientSessionImpl - Closing session
> for reference, this is the remote log, it helps to more clearly show the sequence of packets going to/from the local end:
> [09:42:32.449] [NioProcessor-1] DEBUG RelaySession - networkSessionClosed
> [09:42:32.450] [NioProcessor-1] DEBUG RelaySessionSshChannelSender - Send SSH_MSG_CHANNEL_CLOSE on channel 0
> [09:42:32.456] [NioProcessor-4] DEBUG SshSession - Received packet SSH_MSG_CHANNEL_CLOSE
> [09:42:32.456] [NioProcessor-4] DEBUG RelaySessionSshChannelSender - Received SSH_MSG_CHANNEL_CLOSE on channel 0
> [09:42:32.457] [NioProcessor-4] DEBUG SshSession - Received packet SSH_MSG_CHANNEL_DATA
> [09:42:32.457] [NioProcessor-4] WARN SshSession - Exception caught
> org.apache.sshd.common.SshException: Received SSH_MSG_CHANNEL_DATA on unknown channel 0
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