From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7E58C433DF for ; Wed, 13 May 2020 18:08:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 632C120659 for ; Wed, 13 May 2020 18:08:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389975AbgEMSIM (ORCPT ); Wed, 13 May 2020 14:08:12 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:38403 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732488AbgEMSIM (ORCPT ); Wed, 13 May 2020 14:08:12 -0400 Received: from localhost (unknown [50.39.163.217]) (Authenticated sender: josh@joshtriplett.org) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 7129A240006; Wed, 13 May 2020 18:07:50 +0000 (UTC) Date: Wed, 13 May 2020 11:07:46 -0700 From: Josh Triplett To: Luis Chamberlain Cc: "Eric W. Biederman" , viro@zeniv.linux.org.uk, gregkh@linuxfoundation.org, rafael@kernel.org, jeyu@kernel.org, jmorris@namei.org, keescook@chromium.org, paul@paul-moore.com, stephen.smalley.work@gmail.com, eparis@parisplace.org, nayna@linux.ibm.com, zohar@linux.ibm.com, scott.branden@broadcom.com, dan.carpenter@oracle.com, skhan@linuxfoundation.org, geert@linux-m68k.org, tglx@linutronix.de, bauerman@linux.ibm.com, dhowells@redhat.com, linux-integrity@vger.kernel.org, linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] security: add symbol namespace for reading file data Message-ID: <20200513180746.GA75734@localhost> References: <20200513152108.25669-1-mcgrof@kernel.org> <20200513152108.25669-3-mcgrof@kernel.org> <87k11fonbk.fsf@x220.int.ebiederm.org> <20200513161622.GS11244@42.do-not-panic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200513161622.GS11244@42.do-not-panic.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, May 13, 2020 at 04:16:22PM +0000, Luis Chamberlain wrote: > On Wed, May 13, 2020 at 10:40:31AM -0500, Eric W. Biederman wrote: > > Luis Chamberlain writes: > > > > > Certain symbols are not meant to be used by everybody, the security > > > helpers for reading files directly is one such case. Use a symbol > > > namespace for them. > > > > > > This will prevent abuse of use of these symbols in places they were > > > not inteded to be used, and provides an easy way to audit where these > > > types of operations happen as a whole. > > > > Why not just remove the ability for the firmware loader to be a module? > > > > Is there some important use case that requires the firmware loader > > to be a module? > > > > We already compile the code in by default. So it is probably just > > easier to remove the modular support all together. Which would allow > > the export of the security hooks to be removed as well. > > Yeah, that's a better solution. The only constaint I am aware of is > we *cannot* change the name of the module from firmware_class since the > old fallback sysfs loader depends on the module name. So, so long as we > take care with that on built-in and document this very well, I think > we should be good. > > I checked the commit logs and this was tristate since the code was added > upstream, so I cannot see any good reason it was enabled as modular. > > Speaking with a *backports experience* hat on, we did have a use case > to use a module for it in case a new feature was added upstream which > was not present on older kernels. However I think that using a separate > symbol prefix would help with that. > > Would any Android stakeholders / small / embedded folks whave any issue > with this? As long as you can still *completely* compile out firmware loading, I don't think there's a huge use case for making it modular. y/n seems fine.