Re: ee using 99% cpu after user ssh session terminates abnormaly

From: Giorgos Keramidas (keramida_at_freebsd.org)
Date: 09/08/05

  • Next message: Yar Tikhiy: "Re: ee using 99% cpu after user ssh session terminates abnormaly"
    Date: Thu, 8 Sep 2005 02:51:32 +0300
    To: Craig Edwards <brain@winbot.co.uk>
    
    

    On 2005-09-08 00:02, Craig Edwards <brain@winbot.co.uk> wrote:
    > At least this is what i suspect happens. Lazy programming somewhere...
    > Brooks Davis wrote:
    > >On Thu, Sep 08, 2005 at 08:27:13AM +1000, talonz wrote:
    > >>Recently i have been using a dialup 56k account to access the net
    > >>and have noticed that when my ssh session times out and I am editing
    > >>a file in ` ee ' the system goes to 99% cpu usage and stays like
    > >>this till the pid is killed. This is a standard user account (not
    > >>root/su)
    > >>
    > >>Would a user be able to create a denial of service condition on the
    > >>remote system using this bug?
    > >
    > >No more then they could with the ablity to run any other program that
    > >loops.
    >
    > I can duplicate this with nano on freebsd 5.4 and 5.2.1
    >
    > It seems that the process ignores the HUP signal maybe or ignores the
    > EOF condition on stdin, and the select loop, or whatever it uses, just
    > loops infinitely with nothing to read, constantly returning an error
    > condition.

    FWIW, pico seems to handle HUP just fine. So whatever causes nano to
    enter a loop is something that is done differently in nano.

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