linux-kernel - Re: Fork Bombing Patch

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Date:	Wed, 22 Aug 2007 11:47:18 +0530
From:	"Anand Jahagirdar" <anandjigar@...il.com>
To:	"Chris Snook" <csnook@...hat.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Fork Bombing Patch

Hi
   I am forwarding one more improved patch which i have modified as
per your suggestions. Insted of KERN_INFO i have used KERN_NOTICE and
i have added one more if block to check hard limit. how good it is?

anand

On 8/20/07, Chris Snook <csnook@...hat.com> wrote:
> Anand Jahagirdar wrote:
> > Hi
> >    As Per the Previous Discussion of my Patch,I think insted of using
> > KERN_CRIT,it is better to lower the priority level to KERN_WARNING.
> > thats why i used KERN_WARNING.it will warn administrator and its
> > administrator responsibility to take whatever action he want to take.
> >
> > anand
>
> Philosophically, I'm okay with the idea of a forkbomb meriting KERN_WARN
> priority, but we should never have a printk that can be trivially triggered by
> an unprivileged user that gets anything higher than KERN_INFO.  If I'm an
> attacker, and I want to do bad things without getting logged, the first thing I
> do is launch a carefully-tuned forkbomb that doesn't bog down the system, just
> triggers this message as often as the ratelimit will allow.  Once /var/log is
> full, I can do my nastiness.  Administrators need to be able to protect against
> that kind of thing without losing the ability to log KERN_WARN and higher
> priority messages.
>
> Also, I stand by my assertion that we should only be complaining if the hard
> limit is also exceeded, since it's totally valid for an application to
> self-constrain using soft limits.  It may be uncommon, but the people who happen
> to use whatever applications do this will be very unhappy when they update their
> kernel and /var fills up from this spew.
>
>        -- Chris
>

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