Re: Simple DoS...out of resources?

Alan Cox (alan@lxorguk.ukuu.org.uk)
Mon, 8 Mar 1999 20:48:56 +0000 (GMT)


> It is very easy to crash a system simply by viewing a large file with
> editor such as pico. It will eat up all the resources and do some
> unpredictible things. In my case I viewed a 100mb file as it was reading
> it, it filled up all the swap space which is 48mb. It killed most of the
> processes including sendmail, sshd, X, syslog. Does anyone have any idea
> how can i protect myself against that kind of DoS? My configuration:
> P100, 48mb ram, 48mb swap running on kernel 2.2.2.

Look at the resource limit features in the system. The default is "anything
goes". Thats paticularly bad on 2.2.* because it tends to kill everything
but the victim. Also the 8K kernel stack problem ensures that it messes
up process creation and other stuff until it dies (and sometimes after)

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