Re: How a normal user can crash any linux system (fwd)

From: Alfred Perlstein (bright@wintelcom.net)
Date: Wed Mar 22 2000 - 17:26:23 EST

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    * Jim Bryant <jbryant@ppp-207-193-186-239.kscymo.swbell.net> [000322 14:19] wrote:
    > In reply:
    > > This is cross-posted to both linux-kernel and freebsd-hackers, please
    > > set your replies properly.
    > >
    > > > I found the following by accident playing with PVM. If you start the
    > > > 'gexample' from the examples directory with dimension=10000 and no of
    > > > tasks=32 on one machine, it becomes almost immediately completely un-
    > > > usable and begins with heavy swapping. Considering how much memory
    > > > would be necessary for this computation before starting it would have
    > > > avoided the trouble.
    >
    > well, there are other ways to make a system slow to a crawl....
    >
    > a good preventative measure is to never give shell accounts unless
    > everyone is accountable.

    True.

    >
    > #!/bin/csh
    > /usr/games/primes 1 4294967295 >&/dev/null&

    ....

    > /usr/games/primes 1 4294967295 >&/dev/null&
    > # etc, ...
    > #
    > # [get the idea?]

    why are you 'scripting' in csh? eww.

    No i don't get the idea, login.conf in FreeBSD is able to limit a user
    to a maximum amount of processes, I think even cputime limitations work
    but I haven't tried them.

    Yes, and one shouldn't give accounts out to irresponcible/thoughtless
    people. 'rmuser' is your friend.

    -- 
    -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
    

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