From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932282AbeDZXZ7 (ORCPT ); Thu, 26 Apr 2018 19:25:59 -0400 Received: from mail-vk0-f67.google.com ([209.85.213.67]:36463 "EHLO mail-vk0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752991AbeDZXZ6 (ORCPT ); Thu, 26 Apr 2018 19:25:58 -0400 X-Google-Smtp-Source: AB8JxZqPP37tluzvzD1XrPS6HXp9JV+cr0felq2R4a0hp++wtRKXIITBcKOIm2bFOn9kiEbMNE+sKCdlTTu5S6qHJIQ= MIME-Version: 1.0 In-Reply-To: References: <20180313162411.GA1983@embeddedgus> <20180314110834.GB8564@ulmo> From: Kees Cook Date: Thu, 26 Apr 2018 16:25:56 -0700 X-Google-Sender-Auth: d6NzKf1mhVKOjminwT49qkGfH4E Message-ID: Subject: Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage To: Ben Skeggs Cc: Thierry Reding , "Gustavo A. R. Silva" , David Airlie , nouveau@lists.freedesktop.org, LKML , Maling list - DRI developers , David Laight , Ben Skeggs 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 Thu, Mar 15, 2018 at 7:05 PM, Ben Skeggs wrote: > On 14 March 2018 at 21:08, Thierry Reding wrote: >> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote: >>> In preparation to enabling -Wvla, remove VLA. In this particular >>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local >>> variable cmdline_size. Also, remove cmdline_size as it is not >>> actually useful anymore. >>> >>> The use of stack Variable Length Arrays needs to be avoided, as they >>> can be a vector for stack exhaustion, which can be both a runtime bug >>> or a security flaw. Also, in general, as code evolves it is easy to >>> lose track of how big a VLA can get. Thus, we can end up having runtime >>> failures that are hard to debug. >>> >>> Also, fixed as part of the directive to remove all VLAs from >>> the kernel: https://lkml.org/lkml/2018/3/7/621 >>> >>> Signed-off-by: Gustavo A. R. Silva >>> --- >>> Changes in v2: >>> - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change >>> is based on the feedback provided by David Laight. Thanks David. >>> >>> drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++---- >>> 1 file changed, 3 insertions(+), 4 deletions(-) >> >> Reviewed-by: Thierry Reding > Thanks everyone. I've taken the patch in my tree. Hi! Just checking in on this -- I don't see this patch in linux-next. Is this queued somewhere else? Thanks! -Kees -- Kees Cook Pixel Security