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From: Darren Reed <avalon@caligula.anu.edu.au>
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To: silby@silby.com (Mike Silbersack)
Date: Wed, 3 Mar 2004 04:30:23 +1100 (Australia/ACT)
In-Reply-To: <20040302111509.E12133@odysseus.silby.com> from "Mike Silbersack"
	at Mar 02, 2004 11:18:01 AM
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cc: freebsd-security@freebsd.org
Subject: Re: mbuf vulnerability
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In some mail from Mike Silbersack, sie said:
> On Wed, 3 Mar 2004, Darren Reed wrote:
> 
> > IPFilter v4 can prevent this attack with:
> >
> > pass in .. proto tcp ... keep state(strict)
> 
> Nope, I just tested this.  Well, I should say that it doesn't provide any
> protection with "keep state"... what does (strict) mean?  The ipf in
> FreeBSD doesn't seem to support it.

Uh, what did you test and what did you test with ?

"strict" requires that the sequence number in packet n should match
what that sequence number of the last byte in packet n-1 - i.e. no
out of order delivery is permitted.

Darren