From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752193AbbJFIXU (ORCPT ); Tue, 6 Oct 2015 04:23:20 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:37126 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbbJFIXP (ORCPT ); Tue, 6 Oct 2015 04:23:15 -0400 Subject: Re: [dpdk-dev] [PATCH 2/2] uio: new driver to support PCI MSI-X To: "Michael S. Tsirkin" References: <1443652138-31782-1-git-send-email-stephen@networkplumber.org> <1443652138-31782-3-git-send-email-stephen@networkplumber.org> <20151001104505-mutt-send-email-mst@redhat.com> <20151005215455.GA7608@redhat.com> <20151006013000-mutt-send-email-mst@redhat.com> Cc: hjk@hansjkoch.de, dev@dpdk.org, gregkh@linux-foundation.org, Stephen Hemminger , linux-kernel@vger.kernel.org From: Vlad Zolotarov Message-ID: <561384EF.8020100@cloudius-systems.com> Date: Tue, 6 Oct 2015 11:23:11 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20151006013000-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/06/15 01:49, Michael S. Tsirkin wrote: > On Tue, Oct 06, 2015 at 01:09:55AM +0300, Vladislav Zolotarov wrote: >> How about instead of trying to invent the wheel just go and attack the problem >> directly just like i've proposed already a few times in the last days: instead >> of limiting the UIO limit the users that are allowed to use UIO to privileged >> users only (e.g. root). This would solve all clearly unresolvable issues u are >> raising here all together, wouldn't it? > No - root or no root, if the user can modify the addresses in the MSI-X > table and make the chip corrupt random memory, this is IMHO a non-starter. Michael, how this or any other related patch is related to the problem u r describing? The above ability is there for years and if memory serves me well it was u who wrote uio_pci_generic with this "security flaw". ;) This patch in general only adds the ability to receive notifications per MSI-X interrupt and it has nothing to do with the ability to reprogram the MSI-X related registers from the user space which was always there. > > And tainting kernel is not a solution - your patch adds a pile of > code that either goes completely unused or taints the kernel. > Not just that - it's a dedicated userspace API that either > goes completely unused or taints the kernel. > >>> -- >>> MST