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Date:      Wed, 22 Mar 2000 14:26:23 -0800
From:      Alfred Perlstein <bright@wintelcom.net>
To:        kc5vdj@swbell.net
Cc:        rminnich@lanl.gov, hackers@FreeBSD.ORG, linux-kernel@vger.rutgers.edu, Michael.Lampe@iwr.uni-heidelberg.de
Subject:   Re: How a normal user can crash any linux system (fwd)
Message-ID:  <20000322142623.R7305@fw.wintelcom.net>
In-Reply-To: <200003222155.PAA35282@ppp-207-193-186-239.kscymo.swbell.net>; from jbryant@ppp-207-193-186-239.kscymo.swbell.net on Wed, Mar 22, 2000 at 03:55:17PM -0600
References:  <20000322102407.K7305@fw.wintelcom.net> <200003222155.PAA35282@ppp-207-193-186-239.kscymo.swbell.net>

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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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