Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932738Ab1BYTIH (ORCPT ); Fri, 25 Feb 2011 14:08:07 -0500 Received: from exchange.solarflare.com ([216.237.3.220]:4492 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932436Ab1BYTIF (ORCPT ); Fri, 25 Feb 2011 14:08:05 -0500 Subject: Re: [PATCH] don't allow CAP_NET_ADMIN to load non-netdev kernel modules From: Ben Hutchings To: David Miller Cc: segoon@openwall.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kuznet@ms2.inr.ac.ru, pekkas@netcore.fi, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, eric.dumazet@gmail.com, therbert@google.com, xiaosuo@gmail.com, jesse@nicira.com, kees.cook@canonical.com, eugene@redhat.com, dan.j.rosenberg@gmail.com, akpm@linux-foundation.org In-Reply-To: <20110225.110529.39178636.davem@davemloft.net> References: <20110225151414.GA5211@albatros> <20110225.104720.71110261.davem@davemloft.net> <20110225190205.GA4541@albatros> <20110225.110529.39178636.davem@davemloft.net> Content-Type: text/plain; charset="UTF-8" Organization: Solarflare Communications Date: Fri, 25 Feb 2011 19:07:59 +0000 Message-ID: <1298660879.2554.23.camel@bwh-desktop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 (2.32.1-1.fc14) Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 25 Feb 2011 19:08:04.0684 (UTC) FILETIME=[5465A0C0:01CBD51F] X-TM-AS-Product-Ver: SMEX-8.0.0.1181-6.500.1024-17976.005 X-TM-AS-Result: No--33.537200-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2098 Lines: 50 On Fri, 2011-02-25 at 11:05 -0800, David Miller wrote: > From: Vasiliy Kulikov > Date: Fri, 25 Feb 2011 22:02:05 +0300 > > > On Fri, Feb 25, 2011 at 10:47 -0800, David Miller wrote: > >> From: Vasiliy Kulikov > >> Date: Fri, 25 Feb 2011 18:14:14 +0300 > >> > >> > Since a8f80e8ff94ecba629542d9b4b5f5a8ee3eb565c any process with > >> > CAP_NET_ADMIN may load any module from /lib/modules/. This doesn't mean > >> > that CAP_NET_ADMIN is a superset of CAP_SYS_MODULE as modules are limited > >> > to /lib/modules/**. However, CAP_NET_ADMIN capability shouldn't allow > >> > anybody load any module not related to networking. > >> > >> Why go through this naming change, which does break things, instead of > >> simply adding a capability mask tag or similar to modules somehow. You > >> could stick it into a special elf section or similar. > >> > >> Doesn't that make tons more sense than this? > > > > This is not "simply", adding special section for a single workaround > > seems like an overkill for me - this touches the core (modules' > > internals), which is not related to the initial CAP_* problem at all. > > > > I'd be happy with not breaking anything, but I don't see any acceptable > > solution. > > I think it's warranted given that it allows us to avoid breaking things. > > I don't understand there is resistence in response to the first idea > I've seen proprosed that actually allows to fix the problem and not > break anything at the same time. > > That seems silly. You realise that module loading doesn't actually run in the context of request_module(), right? Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/