From: Ian Jackson <iwj@xenproject.org>
To: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
Cc: Jason Andryuk <jandryuk@gmail.com>,
Scott Davis <scottwd@gmail.com>,
xen-devel <xen-devel@lists.xenproject.org>,
Scott Davis <scott.davis@starlab.io>, Wei Liu <wl@xen.org>,
George Dunlap <george.dunlap@citrix.com>,
Nick Rosbrook <rosbrookn@ainfosec.com>,
Anthony PERARD <anthony.perard@citrix.com>,
Juergen Gross <jgross@suse.com>,
Daniel De Graaf <dgdegra@tycho.nsa.gov>,
"Daniel P . Smith" <dpsmith@apertussolutions.com>
Subject: Re: [XEN PATCH] tools/xl: Add device_model_stubdomain_init_seclabel option to xl.cfg
Date: Tue, 27 Jul 2021 14:32:22 +0100 [thread overview]
Message-ID: <24832.2790.631888.595948@mariner.uk.xensource.com> (raw)
In-Reply-To: <YP/5wL2p/CGR5g7D@mail-itl>
Marek Marczykowski-Górecki writes ("Re: [XEN PATCH] tools/xl: Add device_model_stubdomain_init_seclabel option to xl.cfg"):
> On Mon, Jul 26, 2021 at 09:07:03AM -0400, Jason Andryuk wrote:
> > Sort of relatedly, is stubdom unpaused before the guest gets
> > relabeled? Quickly looking, I think stubdom is unpaused. I would
> > think you want them both relabeled before either is unpaused. If the
> > stubdom starts with the exec_label, but it sees the guest with the
> > init_label, it may get an unexpected denial? On the other hand,
> > delayed unpausing of stubdom would slow down booting.
>
> Some parts of the stubdomain setup are done after it's unpaused (but
> before the guest is unpaused). Especially, PCI devices are hot-plugged
> only when QEMU is already running (not sure why).
I think the PCI hotplug involves interaction with QEMU, and providing
only hotplug simplifies the code in libxl. Anthony, do I have that
righgt ?
Naively, it seems to me that the security risks are limited because
until the guest is unpaused it doesn't have the ability to do
anything, so cannot yet mount an attack on qemu. So I'm expecting
that qemu is still trustworthy until the guest is unpaused.
Ian.
next prev parent reply other threads:[~2021-07-27 13:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-23 4:47 [XEN PATCH] tools/xl: Add device_model_stubdomain_init_seclabel option to xl.cfg Scott Davis
2021-07-26 13:07 ` Jason Andryuk
2021-07-27 12:19 ` Marek Marczykowski-Górecki
2021-07-27 13:32 ` Ian Jackson [this message]
2021-07-27 13:50 ` Jason Andryuk
2021-07-28 12:19 ` Anthony PERARD
2021-07-28 22:11 ` Scott Davis
2021-07-27 11:45 ` Andrew Cooper
2021-07-27 13:30 ` Ian Jackson
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