From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pj1-f65.google.com ([209.85.216.65]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jYu3V-0006NA-2K for kexec@lists.infradead.org; Wed, 13 May 2020 16:16:26 +0000 Received: by mail-pj1-f65.google.com with SMTP id k7so6328491pjs.5 for ; Wed, 13 May 2020 09:16:24 -0700 (PDT) Date: Wed, 13 May 2020 16:16:22 +0000 From: Luis Chamberlain Subject: Re: [PATCH 2/3] security: add symbol namespace for reading file data Message-ID: <20200513161622.GS11244@42.do-not-panic.com> References: <20200513152108.25669-1-mcgrof@kernel.org> <20200513152108.25669-3-mcgrof@kernel.org> <87k11fonbk.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87k11fonbk.fsf@x220.int.ebiederm.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: "Eric W. Biederman" , Josh Triplett Cc: rafael@kernel.org, zohar@linux.ibm.com, dhowells@redhat.com, paul@paul-moore.com, nayna@linux.ibm.com, jmorris@namei.org, geert@linux-m68k.org, dan.carpenter@oracle.com, keescook@chromium.org, scott.branden@broadcom.com, selinux@vger.kernel.org, viro@zeniv.linux.org.uk, skhan@linuxfoundation.org, eparis@parisplace.org, tglx@linutronix.de, gregkh@linuxfoundation.org, stephen.smalley.work@gmail.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, jeyu@kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, bauerman@linux.ibm.com 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? Luis _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec