From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from terminus.zytor.com ([198.137.202.10]:42238 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755874Ab3CTBAh (ORCPT ); Tue, 19 Mar 2013 21:00:37 -0400 Message-ID: <51490A22.1080908@zytor.com> Date: Tue, 19 Mar 2013 18:00:18 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 To: Matthew Garrett CC: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org Subject: Re: [PATCH 06/12] x86: Require CAP_COMPROMISE_KERNEL for IO port access References: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> <1363642353-30749-6-git-send-email-matthew.garrett@nebula.com> In-Reply-To: <1363642353-30749-6-git-send-email-matthew.garrett@nebula.com> Content-Type: text/plain; charset=UTF-8 Sender: linux-pci-owner@vger.kernel.org List-ID: On 03/18/2013 02:32 PM, Matthew Garrett wrote: > 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. > Again, if you are going to do this, just kill bloody RAWIO. Quite frankly saying brainfucked SCSI drivers have abused it doesn't hold water, because as far as you know those same commands can trigger arbitrary DMA activity. -hpa