From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756162Ab1LVXsj (ORCPT ); Thu, 22 Dec 2011 18:48:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:31561 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752209Ab1LVXsh (ORCPT ); Thu, 22 Dec 2011 18:48:37 -0500 Date: Thu, 22 Dec 2011 23:48:30 +0000 From: Alasdair G Kergon To: Linus Torvalds Cc: Paolo Bonzini , linux-kernel@vger.kernel.org, security@kernel.org, pmatouse@redhat.com, agk@redhat.com, jbottomley@parallels.com, mchristi@redhat.com, msnitzer@redhat.com Subject: Re: [PATCH 2/3] block: fail SCSI passthrough ioctls on partition devices Message-ID: <20111222234830.GC31021@agk-dp.fab.redhat.com> Mail-Followup-To: Linus Torvalds , Paolo Bonzini , linux-kernel@vger.kernel.org, security@kernel.org, pmatouse@redhat.com, agk@redhat.com, jbottomley@parallels.com, mchristi@redhat.com, msnitzer@redhat.com References: <1324576939-23619-1-git-send-email-pbonzini@redhat.com> <1324576939-23619-3-git-send-email-pbonzini@redhat.com> <4EF38269.7080804@redhat.com> <4EF391A6.2040504@redhat.com> <4EF3AA74.1060801@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: 64 Baker Street, 4th floor, London, W1U 7DF. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 22, 2011 at 02:25:56PM -0800, Linus Torvalds wrote: > I don't *think* anybody does something as crazy as giving actual block > device ownership to people, That can happen when running virtual machines backed by logical volumes. Say I am running a server that offers virtual machines to different people, and I allow those people to have root access within their own guest, but, naturally, I don't give them any access to other people's guests. I pool my disks on the server into a Volume Group and create one simple Logical Volume per guest VM to hold its filesystem. Due to this bug, a root user inside one guest VM can see and modify the contents of other VMs that don't belong to them (and in some situations perhaps even take control of the host machine by modifying the host's LVM metadata). Alasdair