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Re: [Qemu-devel] live snapshot wiki updated
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] live snapshot wiki updated |
Date: |
Fri, 22 Jul 2011 09:22:43 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110621 Fedora/3.1.11-1.fc15 Thunderbird/3.1.11 |
Am 21.07.2011 17:01, schrieb Stefan Hajnoczi:
> On Thu, Jul 21, 2011 at 3:02 PM, Eric Blake <address@hidden> wrote:
>> Thank you for persisting - you've found another hole that needs to be
>> plugged. It sounds like you are proposing that after a qemu process dies,
>> that libvirt re-reads the qcow2 metadata headers, and validates that the
>> backing file information has not changed in a manner unexpected by libvirt.
>> If it has, then the qemu process that just died was compromised to the
>> point that restarting a new qemu process from the old image is now a
>> security risk. So this is _yet another_ security aspect that needs to be
>> coded into libvirt as part of hardening sVirt.
>
> The backing file information changes when image streaming completes.
>
> Before: fedora.img <- my_vm.qed
> After: my_vm.qed (fedora.img is no longer referenced)
>
> The image streaming operation copies data out of fedora.img and
> populates my_vm.qed. When image streaming completes, the backing file
> is no longer needed and my_vm.qed is updated to drop the backing file.
>
> I think we need to design carefully to prevent QEMU and libvirt making
> incorrect assumptions about who does what. I really wish that all
> this image file business was outside QEMU and libvirt - that we had a
> separate storage management service which handled the details. QEMU
> would only do block device operations (no image format manipulation),
> and libvirt would only delegate to the storage management service.
And how do you implement that in a way that works on all platforms, and
without root privileges? I can't see this happen unless it stays
completely optional.
Kevin
- Re: [Qemu-devel] live snapshot wiki updated, (continued)
- Re: [Qemu-devel] live snapshot wiki updated, Jes Sorensen, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Daniel P. Berrange, 2011/07/20
- [Qemu-devel] [libvirt] Re: live snapshot wiki updated, Nicolas Sebrecht, 2011/07/20
- Re: [Qemu-devel] [libvirt] Re: live snapshot wiki updated, Daniel P. Berrange, 2011/07/20
- Re: [Qemu-devel] [libvirt] live snapshot wiki updated, Stefan Hajnoczi, 2011/07/20
- Message not available
- Message not available
- Message not available
- Re: [Qemu-devel] [libvirt] live snapshot wiki updated, Eric Blake, 2011/07/21
- Message not available
- Message not available
- Re: [Qemu-devel] live snapshot wiki updated, Stefan Hajnoczi, 2011/07/21
- Re: [Qemu-devel] live snapshot wiki updated, Blue Swirl, 2011/07/21
- Re: [Qemu-devel] live snapshot wiki updated, Stefan Hajnoczi, 2011/07/22
- Re: [Qemu-devel] live snapshot wiki updated, Blue Swirl, 2011/07/22
- Re: [Qemu-devel] live snapshot wiki updated,
Kevin Wolf <=
- Re: [Qemu-devel] live snapshot wiki updated, Stefan Hajnoczi, 2011/07/22
- Re: [Qemu-devel] live snapshot wiki updated, Blue Swirl, 2011/07/22
- Re: [Qemu-devel] live snapshot wiki updated, Kevin Wolf, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Daniel P. Berrange, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Anthony Liguori, 2011/07/19
- Re: [Qemu-devel] live snapshot wiki updated, Jes Sorensen, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Kevin Wolf, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Jes Sorensen, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Kevin Wolf, 2011/07/20
- Re: [Qemu-devel] live snapshot wiki updated, Blue Swirl, 2011/07/20