From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756526Ab1BJO2q (ORCPT ); Thu, 10 Feb 2011 09:28:46 -0500 Received: from 184-106-158-135.static.cloud-ips.com ([184.106.158.135]:36848 "EHLO mail" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756472Ab1BJO2p (ORCPT ); Thu, 10 Feb 2011 09:28:45 -0500 Date: Thu, 10 Feb 2011 14:29:38 +0000 From: "Serge E. Hallyn" To: Gergely Nagy Cc: "Serge E. Hallyn" , david@lang.hm, James Morris , Linux Kernel Mailing List Subject: Re: CAP_SYSLOG, 2.6.38 and user space Message-ID: <20110210142938.GA1475@mail.hallyn.com> References: <1296733177.14846.26.camel@moria> <20110203153252.GA24153@mail.hallyn.com> <20110204160513.GB17396@mail.hallyn.com> <1296837186.24742.15.camel@moria> <20110204171502.GA24226@mail.hallyn.com> <20110206011831.GB15805@mail.hallyn.com> <20110209212329.GA24777@mail.hallyn.com> <1297286934.13055.57.camel@luthien.mhp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1297286934.13055.57.camel@luthien.mhp> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Gergely Nagy (algernon@balabit.hu): > On Wed, 2011-02-09 at 21:23 +0000, Serge E. Hallyn wrote: > > So if that's how we're leaning, then the following patch is much more > > concise. I'll send this to Linus and any appropriate -stable tomorrow > > if noone objects. > > > > From 5166e114d6a7c508addbadd763322089eb0b02f5 Mon Sep 17 00:00:00 2001 > > From: Serge Hallyn > > Date: Thu, 3 Feb 2011 09:26:15 -0600 > > Subject: [PATCH 1/1] cap_syslog: don't refuse cap_sys_admin for now (v2) > > > > It'd be nice to do that later, but it's not strictly necessary, > > and it'll be hard to do without breaking somebody's userspace. > > > > Signed-off-by: Serge Hallyn > > --- > > kernel/printk.c | 14 ++++---------- > > 1 files changed, 4 insertions(+), 10 deletions(-) > > Personally, I'd prefer the sysctl idea in the long run, because > userspace can easily and automatically adapt to the running kernel then. > Ie, this patch is fine for 2.6.38, but later on, a sysctl could be > introduced, that when set (but defaulting to unset, as to not break > userspace), would make CAP_SYS_ADMIN return -EPERM. That way, syslogds > could look at the setting, and act accordingly. This would mean that old > userspace wouldn't break, and upgraded userspace could work on both old > and new kernels, depending on the setting. Distros or admins could then > enable the sysctl once they made sure that all neccessary applications > have been upgraded. > > But this works too, for now. My immediate concern is making sure 2.6.38 > doesn't break capability-using syslogds. Ok, I'll forward the previous patch. thanks, -serge