Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756030Ab2FJTQm (ORCPT ); Sun, 10 Jun 2012 15:16:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59784 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754901Ab2FJTQk (ORCPT ); Sun, 10 Jun 2012 15:16:40 -0400 Date: Sun, 10 Jun 2012 22:16:54 +0300 From: "Michael S. Tsirkin" To: "Hans J. Koch" Cc: Alex Williamson , Andreas Hartmann , Dominic Eschweiler , Jan Kiszka , Greg Kroah-Hartman , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] uio_pci_generic does not export memory resources Message-ID: <20120610191654.GE10523@redhat.com> References: <1339166867.3870.29.camel@blech> <4FD22552.6090609@01019freenet.de> <20120608164426.GE9705@local> <1339175476.26976.102.camel@ul30vt> <20120610141759.GB8922@redhat.com> <1339344566.26976.272.camel@ul30vt> <20120610164429.GB9879@redhat.com> <1339349905.26976.306.camel@ul30vt> <20120610190036.GD10523@redhat.com> <20120610191130.GC2629@local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120610191130.GC2629@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 29 On Sun, Jun 10, 2012 at 09:11:30PM +0200, Hans J. Koch wrote: > On Sun, Jun 10, 2012 at 10:00:36PM +0300, Michael S. Tsirkin wrote: > > > > One thing I stand corrected on: assigning a PF that does DMA with VFIO > > *might* be secure, and sometimes, maybe often, is. > > There's just no way to make sure. > > This is unlike uio_pci_generic where it would always be insecure. > > You need to be root to access a UIO device, and if you're root, you can > compromise a system in many ways. Before UIO, people used /dev/mem for > similar purposes, and UIO is certainly a seccurity improvement over that. > > But of course, UIO presents security risks. Like many other things below > /dev, you need to know what you're doing, and who gets access to /dev/uioX. > > Thanks, > Hans Sorry I might not have explained myself clearly. uio_pci_generic would be insecure if used with a device doing DMA. I am not speaking about UIO in general at all. -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/