From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753305AbdH2Pz7 (ORCPT ); Tue, 29 Aug 2017 11:55:59 -0400 Received: from mga14.intel.com ([192.55.52.115]:28697 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbdH2Pz5 (ORCPT ); Tue, 29 Aug 2017 11:55:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,445,1498546800"; d="scan'208";a="1167270979" Date: Tue, 29 Aug 2017 08:55:56 -0700 From: "Luck, Tony" To: Kees Cook Cc: Alan Cox , "Rafael J. Wysocki" , Len Brown , Boris Petkov , Tyler Baicar , Punit Agrawal , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ACPI / sysfs: Extend ACPI sysfs to provide access to boot error region Message-ID: <20170829155554.fukyxs2x3b5evw37@intel.com> References: <20170817213946.16939-1-tony.luck@intel.com> <20170818013047.427e38b7@alans-desktop> <3908561D78D1C84285E8C5FCA982C28F61349912@ORSMSX114.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 28, 2017 at 05:10:33PM -0700, Kees Cook wrote: > On Wed, Aug 23, 2017 at 7:56 AM, Luck, Tony wrote: > >>> Should this not also have a capability check. Assuming file permissions > >>> are sufficient for grabbing a chunk of system memory holding error > >>> info doesn't seem too scary but it's at odds with a lot of other cases ? > >> > >> At least one of those other cases (pstore) added a capability check and now regret > >> it. There's a thread on reverting it. Look for: > >> > >> Revert "pstore: Honor dmesg_restrict sysctl on dmesg dumps" > > > > Here's at least part of that thread: > > > > https://marc.info/?l=linux-kernel&m=150301241114262&w=2 > > > > Kees: you were OK with removing the capability check from pstore, right? > > Yeah, as long as there is comparable protections. File system permission protection is "0400": # ls -al /sys/firmware/acpi/tables/data total 0 drwxr-xr-x. 2 root root 0 Aug 28 14:13 . drwxr-xr-x. 4 root root 0 Aug 28 14:10 .. -r--------. 1 root root 32768 Aug 28 14:13 BERT -Tony