From: zerodaysfordays@sdf.lonestar.org (Jakob L. Kreuze)
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: 36364@debbugs.gnu.org
Subject: bug#36364: Potential SSH session exhaustion
Date: Mon, 24 Jun 2019 19:28:28 -0400 [thread overview]
Message-ID: <877e9awokj.fsf@sdf.lonestar.org> (raw)
In-Reply-To: <87ftny3e6q.fsf@gnu.org> ("Ludovic \=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\= \=\?utf-8\?Q\?s\?\= message of "Mon, 24 Jun 2019 22:45:33 +0200")
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Hi,
Ludovic Courtès <ludo@gnu.org> writes:
> Procedures like ‘send-files’ call ‘channel-get-exit-status’ and
> ‘close-port’ on ports that represent SSH channels.
>
> AFAICS, ‘close-port’ triggers a call of ‘ptob_close’ in Guile-SSH,
> which in turn calls ‘ssh_channel_close’.
>
> sshd_config(5) says:
>
> MaxSessions Specifies the maximum number of open shell, login or subsystem
> (e.g. sftp) sessions permitted per network connection. Multiple sessions may be
> established by clients that support connection multiplexing. Setting MaxSessions
> to 1 will effectively disable session multiplexing, whereas setting it to 0 will
> prevent all shell, login and subsystem sessions while still permitting
> forwarding. The default is 10.
>
> So you must be hitting this limit.
Ah, thank you for the corrections :)
> I see that ‘remote-eval’ does not close ‘remote’ though, so this
> channel port remains open until it’s GC’d, which happens too late.
> Could you try the attached patch? It allows me to do more than 10
> ‘remote-eval’ calls in a row.
Wow, that was quick. The patch works like a charm, thanks!
Regards,
Jakob
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next prev parent reply other threads:[~2019-06-24 23:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 17:23 bug#36364: Potential SSH session exhaustion Jakob L. Kreuze
2019-06-24 20:45 ` Ludovic Courtès
2019-06-24 23:28 ` Jakob L. Kreuze [this message]
2019-06-25 16:14 ` Ludovic Courtès
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