From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B10FC7EE24 for ; Mon, 5 Jun 2023 15:03:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232272AbjFEPDz (ORCPT ); Mon, 5 Jun 2023 11:03:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231945AbjFEPDy (ORCPT ); Mon, 5 Jun 2023 11:03:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0540DDA; Mon, 5 Jun 2023 08:03:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8EDC262097; Mon, 5 Jun 2023 15:03:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87A3BC433D2; Mon, 5 Jun 2023 15:03:52 +0000 (UTC) Date: Mon, 5 Jun 2023 17:03:50 +0200 From: Greg KH To: Thomas Zimmermann Cc: daniel@ffwll.ch, javierm@redhat.com, sam@ravnborg.org, deller@gmx.de, geert+renesas@glider.be, lee@kernel.org, daniel.thompson@linaro.org, jingoohan1@gmail.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-sh@vger.kernel.org, linux-omap@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH 30/30] fbdev: Make support for userspace interfaces configurable Message-ID: <2023060542-daydream-dares-d494@gregkh> References: <20230605144812.15241-1-tzimmermann@suse.de> <20230605144812.15241-31-tzimmermann@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230605144812.15241-31-tzimmermann@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Mon, Jun 05, 2023 at 04:48:12PM +0200, Thomas Zimmermann wrote: > Add Kconfig option CONFIG_FB_DEVICE and make the virtual fbdev > device optional. If the new option has not been selected, fbdev > does not create a files in devfs or sysfs. > > Most modern Linux systems run a DRM-based graphics stack that uses > the kernel's framebuffer console, but has otherwise deprecated fbdev > support. Yet fbdev userspace interfaces are still present. > > The option makes it possible to use the fbdev subsystem as console > implementation without support for userspace. This closes potential > entry points to manipulate kernel or I/O memory via framebuffers. It > also prevents the execution of driver code via ioctl or sysfs, both > of which might allow malicious software to exploit bugs in the fbdev > code. > > A small number of fbdev drivers require struct fbinfo.dev to be > initialized, usually for the support of sysfs interface. Make these > drivers depend on FB_DEVICE. They can later be fixed if necessary. > > Signed-off-by: Thomas Zimmermann Acked-by: Greg Kroah-Hartman