From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFF9AC3A5A2 for ; Fri, 23 Aug 2019 14:11:36 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C886E2173E for ; Fri, 23 Aug 2019 14:11:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C886E2173E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56516 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i1AHw-0006Jz-3K for qemu-devel@archiver.kernel.org; Fri, 23 Aug 2019 10:11:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46353) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i1AGN-0004dC-Kd for qemu-devel@nongnu.org; Fri, 23 Aug 2019 10:10:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i1AGM-0003ec-A5 for qemu-devel@nongnu.org; Fri, 23 Aug 2019 10:09:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43716) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i1AGM-0003eO-2j for qemu-devel@nongnu.org; Fri, 23 Aug 2019 10:09:58 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5DCD12CE905; Fri, 23 Aug 2019 14:09:57 +0000 (UTC) Received: from work-vm (ovpn-117-244.ams2.redhat.com [10.36.117.244]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8EC841C92A; Fri, 23 Aug 2019 14:09:50 +0000 (UTC) Date: Fri, 23 Aug 2019 15:09:48 +0100 From: "Dr. David Alan Gilbert" To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Message-ID: <20190823140948.GI2784@work-vm> References: <20190808150325.21939-1-marcandre.lureau@redhat.com> <20190823112053.GE9654@redhat.com> <20190823114157.GG9654@redhat.com> <20190823130014.GG2784@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 23 Aug 2019 14:09:57 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 0/2] Add dbus-vmstate X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Thomas Huth , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Juan Quintela , qemu-devel , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Marc-Andr=E9 Lureau (marcandre.lureau@gmail.com) wrote: > Hi >=20 > On Fri, Aug 23, 2019 at 5:00 PM Dr. David Alan Gilbert > wrote: > > > > * Daniel P. Berrang=E9 (berrange@redhat.com) wrote: > > > > > > > > > This means QEMU still has to iterate over every single client > > > on the bus to identify them. If you're doing that, there's > > > no point in owning a well known service at all. Just iterate > > > over the unique bus names and look for the exported object > > > path /org/qemu/VMState > > > > > > > Not knowing anything about DBus security, I want to ask how do > > we handle security here? >=20 > First of all, we are talking about cooperative processes, and having a > specific bus for each qemu instance. So some amount of security/trust > is already assumed. Some but we need to keep it as limited as possible; for example two reasons for having separate processes both come down to security: a) vtpm - however screwy the qemu is, you can never get to the keys in the vtpm b) virtio-gpu, loads of complex GPU code that can't break the main qemu process. > But if necessary, dbus can enforce policies on who is allowed to own a > name, or to send/receive message from. As far as I know, this is > mostly user/group policies. >=20 > But there is also SELinux checks to send_msg and acquire_svc (see > dbus-daemon(1)) But how does something like SELinux interact with a private dbus=20 rather than the system dbus? > > > > I want to know that the external device that's giving me migration da= ta > > is the device I think I'm speaking to, not one of the other devices; >=20 > DBus is not the problem nor the solution here. Well, if the migration data was squirting down the existing vhost-user channel then there would be no risk here; so the use of dbus is creating the problem. > But what defines that device-service strong relationship? Can you > generalize it? I don't think so. >=20 > What DBus can guarantee is that the unique-id you are talking to is > always the same connection (thus the same process). >=20 > > I also dont want different devices chatting to each other over dbus > > unless we're very careful. >=20 > That's a bus policy job. OK, as long as you somehow set it up. Dave > > > > Dave > > > > > Regards, > > > Daniel > > > -- > > > |: https://berrange.com -o- https://www.flickr.com/photos/d= berrange :| > > > |: https://libvirt.org -o- https://fstop138.berr= ange.com :| > > > |: https://entangle-photo.org -o- https://www.instagram.com/d= berrange :| > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > >=20 >=20 > --=20 > Marc-Andr=E9 Lureau -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK