Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754681AbdDNS2w (ORCPT ); Fri, 14 Apr 2017 14:28:52 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:42879 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752912AbdDNS2s (ORCPT ); Fri, 14 Apr 2017 14:28:48 -0400 Date: Fri, 14 Apr 2017 20:28:39 +0200 (CEST) From: Thomas Gleixner To: David Howells cc: linux-kernel@vger.kernel.org, matthew.garrett@nebula.com, linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, gregkh@linuxfoundation.org, x86@kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Subject: Re: [PATCH 13/24] x86: Lock down IO port access when the kernel is locked down In-Reply-To: <149142338597.5101.14728426552744019377.stgit@warthog.procyon.org.uk> Message-ID: References: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> <149142338597.5101.14728426552744019377.stgit@warthog.procyon.org.uk> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 617 Lines: 15 On Wed, 5 Apr 2017, David Howells wrote: > From: Matthew Garrett > > IO port access would permit users to gain access to PCI configuration > registers, which in turn (on a lot of hardware) give access to MMIO > register space. This would potentially permit root to trigger arbitrary > DMA, so lock it down by default. > > This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and > KDDISABIO console ioctls. > > Signed-off-by: Matthew Garrett > Signed-off-by: David Howells Reviewed-by: Thomas Gleixner