From owner-freebsd-stable@FreeBSD.ORG  Mon Apr 22 09:45:03 2013
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115])
 by hub.freebsd.org (Postfix) with ESMTP id D7B711D4
 for <freebsd-stable@freebsd.org>; Mon, 22 Apr 2013 09:45:03 +0000 (UTC)
 (envelope-from glebius@FreeBSD.org)
Received: from cell.glebius.int.ru (glebius.int.ru [81.19.69.10])
 by mx1.freebsd.org (Postfix) with ESMTP id 6760B1B8D
 for <freebsd-stable@freebsd.org>; Mon, 22 Apr 2013 09:45:02 +0000 (UTC)
Received: from cell.glebius.int.ru (localhost [127.0.0.1])
 by cell.glebius.int.ru (8.14.6/8.14.6) with ESMTP id r3M9iuSW045426;
 Mon, 22 Apr 2013 13:44:56 +0400 (MSK)
 (envelope-from glebius@FreeBSD.org)
Received: (from glebius@localhost)
 by cell.glebius.int.ru (8.14.6/8.14.6/Submit) id r3M9iuWt045425;
 Mon, 22 Apr 2013 13:44:56 +0400 (MSK)
 (envelope-from glebius@FreeBSD.org)
X-Authentication-Warning: cell.glebius.int.ru: glebius set sender to
 glebius@FreeBSD.org using -f
Date: Mon, 22 Apr 2013 13:44:56 +0400
From: Gleb Smirnoff <glebius@FreeBSD.org>
To: Marcelo Gondim <gondim@bsdinfo.com.br>
Subject: Re: Possible DoS in mpd 5.6 pppoe server
Message-ID: <20130422094456.GB76816@FreeBSD.org>
References: <5172965A.9080600@bsdinfo.com.br> <5172BDDD.4010509@rdtc.ru>
 <5172CFB2.3010708@bsdinfo.com.br>
MIME-Version: 1.0
Content-Type: text/plain; charset=koi8-r
Content-Disposition: inline
In-Reply-To: <5172CFB2.3010708@bsdinfo.com.br>
User-Agent: Mutt/1.5.21 (2010-09-15)
Cc: freebsd-stable@freebsd.org
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 22 Apr 2013 09:45:03 -0000

  Marcelo,

On Sat, Apr 20, 2013 at 02:26:10PM -0300, Marcelo Gondim wrote:
M> >> I'm doing tests with mpdas pppoeserver. Tried to simulate an attack of
M> >> 1000 connections using an incorrect login and after a certain time can
M> >> cause a kernel panic in the system. Below the panicgenerated:
M> >>
M> >> http://pastebin.com/nUXGVR3y
M> > You seem to use dummynet and the problem is not in mpd/pppoe code,
M> > it's it the dummynet code. Look at http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/162558
M> > for workarounds.
M> Ok  :)  I will try this:
M> 
M> - net.isr.bindthreads=1 in /boot/loader.conf;
M> - net.isr.direct=1 and net.isr.direct_force=1 in /etc/sysctl.conf

Be advised, that these settings do not fix the problem with dummynet, they
just make the race less probable to happen.

-- 
Totus tuus, Glebius.