From owner-freebsd-security@FreeBSD.ORG Fri Oct 20 07:41:17 2006 Return-Path: X-Original-To: freebsd-security@freebsd.org 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 50BB816A403; Fri, 20 Oct 2006 07:41:17 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id F3E2B43D45; Fri, 20 Oct 2006 07:41:16 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 944CD46B90; Fri, 20 Oct 2006 03:41:16 -0400 (EDT) Date: Fri, 20 Oct 2006 08:41:16 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Paul Allen In-Reply-To: <20061020011549.GD30707@riyal.ugcs.caltech.edu> Message-ID: <20061020083937.E32598@fledge.watson.org> References: <453531C9.7080304@freebsd.org> <45355C6E.5030703@jim-liesl.org> <20061020004915.V32598@fledge.watson.org> <20061020011549.GD30707@riyal.ugcs.caltech.edu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-security@freebsd.org, security , freebsd-stable@freebsd.org Subject: Re: FreeBSD 4.x EoL X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Oct 2006 07:41:17 -0000 On Thu, 19 Oct 2006, Paul Allen wrote: >> While possibly not advisable in the long term, I ran a 4.x postfix and >> cyrus server install on 6.x using compat4 for about six months without >> problems. The place where it gets tricky is updating the 4.x binaries, >> which requires a 4.x chroot, since I was running a native 6.x userland for >> everything else. I've now gotten over that, but it worked quite well and >> was extremely useful that I could avoid doing the upgrade all at once -- >> upgrade the OS first, let it settle, then upgrade the applications. The >> only issue I ran into was actually that the location of the Cyrus sasl unix >> domain socket had moved, and once I tracked that down, all was well (so not >> a FreeBSD nit, an application nit). > > Let me toss a bit of caution from experience regarding this: > > I too ran such 6.x system. It had a jailed FreeBSD 4.x userland (restored > and modified from the original FreeBSD 4.x backups). Almost everything > worked properly--but there were some strange vm related inconsistencies > (exposed by a program rolling its own gc implementation and using mprotect > and SEGV). > > Obviously this was an unusual case but it's unfortuantely proof that some > things escape having the necessary compat lines in your kernel conf. > > Still I counted myself lucky. When you recompiled the application for 6.x, did the problem go away? I guess I wouldn't entirely preclude an application bug, a 4.x library bug, or a 6.x compat/non-compat bug being responsible. Since 6.x is a fairly major upgrade, there are significant changes in VM (which might well affect, for example, memory layout), etc, so it could well be that it triggered a bug in the GC. Robert N M Watson Computer Laboratory University of Cambridge