RE: sshd does not die when client issues control-C or closes

From: Paul Myers (pmyers_at_spectracomcorp.com)
Date: 03/12/04

  • Next message: Rahul Kalaskar: "Re: Automatic ssh connections" 
    To: "'Darren Tucker'" <dtucker@zip.com.au>, <pmyers@spectracomcorp.com>
Date: Fri, 12 Mar 2004 16:13:25 -0500

    The SSHD Version is 3.5 and I successfully logged in using password
    authentication.

    I am running an application which is sending IO to the connected PTY and
    allowing me to issue commands to another application. BUT I really do
    NOTHING except look at the hello world screen and hit Control-C.

    The Application dies, but the SSHD running under uClinux simply keeps
    running. The child processes die, but uClinux port of SSHD appears to be
    blissfully unaware of that. I am going through the code now to see why.

    There is no default child signal handler being used it appears when inetd
    runs sshd from under uClinux. There is one defined in the code but it is not
    used.

    Thanks,
    Paul

    -----Original Message-----
    From: Darren Tucker [mailto:dtucker@zip.com.au]
    Sent: Friday, March 12, 2004 4:09 PM
    To: pmyers@spectracomcorp.com
    Cc: secureshell@securityfocus.com
    Subject: Re: sshd does not die when client issues control-C or closes

    Paul Myers wrote:
    > I have been tesing OpenSSH sshd

    Which version?

    > running under uClinux using Putty, Terraterm
    > with ssh, and Redhat and found that whenever I close a connection with
    > control-C my child shells die but the sshd -i daemon keeps running and
    holds
    > a PTY. The sshd is launched from inetd as indicated is the default by
    > uClinux makefiles.
    > If I use the x to close the Putty tool both the sshd -i daemon and the
    child
    > processes using 1 PTY keep running.

    Is this with or without logging in?

    > Has anyone seen this and do you know if there might be a configuration
    > issue? Also, I set my Client Keep alive parameters to issue 4 requests
    every
    > 15 seconds. But this does not shutdown the system either.

    Your config is one request every 15 sec, disconnecting after 4 failures.
      Note that this applies only to SSHv2 connections, and PuTTY <= 0.53
    will default to SSHv1 if it's available.

    > My configuration is below. Is there something obvious about how sshd
    should
    > terminate running under uClinux I don't know? Or have I broken something
    in
    > linux?

    Config looks OK to me. 

    --
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.
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