From owner-freebsd-stable@FreeBSD.ORG  Wed Jun 30 18:04:15 2004
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id E3C2D16A4CE
	for <freebsd-stable@freebsd.org>;
	Wed, 30 Jun 2004 18:04:15 +0000 (GMT)
Received: from ion.gank.org (ion.gank.org [69.55.238.164])
	by mx1.FreeBSD.org (Postfix) with ESMTP id B664043D1D
	for <freebsd-stable@freebsd.org>;
	Wed, 30 Jun 2004 18:04:15 +0000 (GMT)
	(envelope-from craig@meoqu.gank.org)
Received: from owen1492.uf.corelab.com (pix.corelab.com [12.45.169.2])
	by ion.gank.org (mail) with ESMTP id 6D0012B613;
	Wed, 30 Jun 2004 13:04:15 -0500 (CDT)
From: Craig Boston <craig@meoqu.gank.org>
To: freebsd-stable@freebsd.org,
	Skylar Thompson <skylar@cs.earlham.edu>
Date: Wed, 30 Jun 2004 13:04:11 -0500
User-Agent: KMail/1.6.2
References: <200406281706.11188.matt@fruitsalad.org>
	<200406281644.i5SGiM0h097809@lurza.secnetix.de>
	<20040630175241.GC54215@quark.cs.earlham.edu>
In-Reply-To: <20040630175241.GC54215@quark.cs.earlham.edu>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <200406301304.11783.craig@meoqu.gank.org>
Subject: Re: Maximum uptime 497 days?
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Production branch of FreeBSD source code
	<freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/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: Wed, 30 Jun 2004 18:04:16 -0000

On Wednesday 30 June 2004 12:52 pm, Skylar Thompson wrote:
> A lot of security holes can be patched without rebooting. In general, only
> kernel updates strictly require a reboot. There have been a few kernel
> security vulnerabilities released in the past couple years, but a lot of
> them are for DoS attacks, not privelege escelation.

Also, _in theory_, even many kernel bugs can be patched without rebooting.
A kernel module can bypass an affected function, for example by replacing 
syscall table entries.  It takes a lot of work and knowledge of the guts of 
the kernel, but it is possible.

I've never done this myself but have seen it used in environments such as 
massive virtual hosting (we may be talking about hundreds of potentially 
affected servers, each with dozens of users), where a reboot is costly and 
painful.

Craig