From owner-freebsd-security@FreeBSD.ORG Wed Apr 21 16:31:31 2004 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0588316A4CE for ; Wed, 21 Apr 2004 16:31:30 -0700 (PDT) Received: from gw.catspoiler.org (217-ip-163.nccn.net [209.79.217.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 94F4843D41 for ; Wed, 21 Apr 2004 16:31:30 -0700 (PDT) (envelope-from truckman@FreeBSD.org) Received: from FreeBSD.org (mousie.catspoiler.org [192.168.101.2]) by gw.catspoiler.org (8.12.9p2/8.12.9) with ESMTP id i3LNVE7E047907; Wed, 21 Apr 2004 16:31:17 -0700 (PDT) (envelope-from truckman@FreeBSD.org) Message-Id: <200404212331.i3LNVE7E047907@gw.catspoiler.org> Date: Wed, 21 Apr 2004 16:31:14 -0700 (PDT) From: Don Lewis To: silby@silby.com, jayanth@yahoo-inc.com In-Reply-To: <20040421184539.H18583@odysseus.silby.com> MIME-Version: 1.0 Content-Type: TEXT/plain; charset=us-ascii cc: freebsd-security@FreeBSD.org cc: avalon@caligula.anu.edu.au Subject: Re: [Full-Disclosure] IETF Draft - Fix for TCP vulnerability (fwd) X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Security issues [members-only posting] List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Apr 2004 23:31:31 -0000 On 21 Apr, Mike Silbersack wrote: > > On Wed, 21 Apr 2004, Don Lewis wrote: > >> > 1. Accept all RSTs meeting the criteria you just listed above. >> >> At this step, it would be better if we used the window size that was >> advertised it the last packet sent, since that is what the sequence >> number of the RST packet will be calculated from, while the window size >> could have increased if data was consumed from the receive queue between >> the time we sent the last packet and when we received the RST. >> >> It doesn't look like we keep the necessary data for this. Probably the >> easiest thing to do would be to calculate the expected sequence number >> in tcp_output() and stash it in the pcb. > > Do you have access to a system that exhibits the "RST at end of window" > syndrome so that you could code up and test out this part of the patch? Nope. The only report of this that I saw was from jayanth. Judging by the tcpdump timestamps, it looks like whatever this wierd piece of hardware was, it was nearby.