From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 06/12] x86: Require CAP_COMPROMISE_KERNEL for IO port access Date: Tue, 19 Mar 2013 18:00:18 -0700 Message-ID: <51490A22.1080908@zytor.com> References: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> <1363642353-30749-6-git-send-email-matthew.garrett@nebula.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1363642353-30749-6-git-send-email-matthew.garrett@nebula.com> Sender: linux-pci-owner@vger.kernel.org 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 List-Id: linux-efi@vger.kernel.org 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