Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757212AbaGVWU6 (ORCPT ); Tue, 22 Jul 2014 18:20:58 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:47677 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756895AbaGVWUy (ORCPT ); Tue, 22 Jul 2014 18:20:54 -0400 MIME-Version: 1.0 In-Reply-To: References: <1405373897-31671-1-git-send-email-keescook@chromium.org> <1405373897-31671-4-git-send-email-keescook@chromium.org> <20140714222419.GC10393@wotan.suse.de> Date: Tue, 22 Jul 2014 15:20:53 -0700 X-Google-Sender-Auth: IQW5yE3565JKsoVSHA3MUUYbhyA Message-ID: Subject: Re: [PATCH 3/7] security: introduce kernel_fw_from_file hook From: Kees Cook To: "Luis R. Rodriguez" Cc: LKML , Ming Lei , Greg Kroah-Hartman , James Morris , David Howells , "linux-doc@vger.kernel.org" , linux-security-module , linux-firmware@kernel.org, linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 22, 2014 at 3:11 PM, Luis R. Rodriguez wrote: > On Tue, Jul 22, 2014 at 1:55 PM, Kees Cook wrote: >> On Tue, Jul 22, 2014 at 12:39 PM, Luis R. Rodriguez wrote: >>> On Mon, Jul 14, 2014 at 3:31 PM, Kees Cook wrote: >>>> Yup, with this and the module hook, adding a similar hook for kexec >>>> makes sense as well. A paranoid kernel doesn't want to trust anything >>>> it's loading from userspace. :) >>> >>> Well I'm actually wondering if we could generalize requiring hooks or >>> not for LSM as part of the general kobject definition. Then we >>> wouldn't need to keep growing hooks for modules, firmware, kexec >>> images, etc, but instead using the interfaces for kobjects and who >>> depend on them. How that would actually look -- I'm not sure, but just >>> a thought. >> >> Yeah, there does seem to be a repeated "get a thing from userspace" >> method here, but the interfaces have been rather scattered so far. I >> haven't seen an obvious way to consolidate them yet. > > If we are going to be adding a new system call for each type of > userspace object to help LSMs with requirements I wonder if its a > worthy endeavor to review. This series didn't add one but you had > mentioned finit_module() for example, are we going to want one for > finit_firmware() finit_kexec_image(), etc? The kernel pulls in firmware directly from the filesystem, so no syscall there. :) kexec just had kexec_load_file added as a syscall (it takes 2 fds: kernel and initrd). -Kees -- Kees Cook Chrome OS Security -- 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/