Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754090AbcKUPZz (ORCPT ); Mon, 21 Nov 2016 10:25:55 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:36494 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753629AbcKUPZx (ORCPT ); Mon, 21 Nov 2016 10:25:53 -0500 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (1.0) Subject: Re: [PATCH 02/16] efi: Get the secure boot status From: Ard Biesheuvel X-Mailer: iPhone Mail (14B100) In-Reply-To: <20161121151758.GA1319@wunner.de> Date: Mon, 21 Nov 2016 15:25:46 +0000 Cc: David Howells , Linn Crosetto , keyrings@vger.kernel.org, Matthew Garrett , linux-security-module , "linux-efi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Message-Id: <891BA2BC-CF94-429C-B452-162EC9A0D6B7@linaro.org> References: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> <147933285147.19316.11046583275861569558.stgit@warthog.procyon.org.uk> <20161117123731.GA11573@wunner.de> <29779.1479728545@warthog.procyon.org.uk> <5701.1479732075@warthog.procyon.org.uk> <20161121151758.GA1319@wunner.de> To: Lukas Wunner Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id uALFPxZH002421 Content-Length: 1866 Lines: 46 > On 21 Nov 2016, at 15:17, Lukas Wunner wrote: > >> On Mon, Nov 21, 2016 at 01:14:52PM +0000, Ard Biesheuvel wrote: >>> On 21 November 2016 at 12:41, David Howells wrote: >>> Ard Biesheuvel wrote: >>>>> Looking in efi_get_secureboot(), is there a reason: >>>>> >>>>> efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID; >>>>> >>>>> isn't static const? >>>> >>>> Not a good one, no. It used to be static const, but for some reason, >>>> commit 30d7bf034c03 ("efi/arm64: Check SetupMode when determining >>>> Secure Boot status") removed the static and the const (and I reviewed >>>> it and did not complain AFAIR) >>>> I'll gladly take a patch that reinstates that, though. >>> >>> Also, is there a reason that: >>> >>> typedef efi_status_t efi_get_variable_t (efi_char16_t *name, efi_guid_t *vendor, u32 *attr, >>> unsigned long *data_size, void *data); >>> >>> Doesn't have const name and vendor? >> >> Yes, but not a good one either. >> >> Sadly, the prototypes in the UEFI spec completely ignore constness, >> and these definitions are intended to be identical to the ones in the >> spec. This also means, for instance, that most UEFI firmwares stores >> these kinds of GUIDs in read-write memory, which is a potential >> goldmine for hackers, given how GUIDs are UEFI's duct tape, i.e., >> keeping the world together. > > But the spec declares these two parameters as "IN", so it would seem > legal to declare them const, no? > Good point. > Incidentally I've already prepared commits a couple of days ago to > change the GUID declarations to const everywhere and also change the > get_variable prototype, I was planning to submit them for 4.11... :-) > I would like to take those, provided that they only modify IN pointer arguments.