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Re: [Qemu-devel] [PATCH] Add support for fd: protocol
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] Add support for fd: protocol |
Date: |
Mon, 23 May 2011 16:28:10 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 |
Am 20.05.2011 21:53, schrieb Blue Swirl:
> On Fri, May 20, 2011 at 10:42 PM, Anthony Liguori <address@hidden> wrote:
>> On 05/20/2011 02:25 PM, Blue Swirl wrote:
>>>
>>> On Fri, May 20, 2011 at 9:48 PM, Corey Bryant<address@hidden> wrote:
>>>>
>>>> sVirt provides SELinux MAC isolation for Qemu guest processes and their
>>>> corresponding resources (image files). sVirt provides this support
>>>> by labeling guests and resources with security labels that are stored
>>>> in file system extended attributes. Some file systems, such as NFS, do
>>>> not support the extended attribute security namespace, which is needed
>>>> for image file isolation when using the sVirt SELinux security driver
>>>> in libvirt.
>>>>
>>>> The proposed solution entails a combination of Qemu, libvirt, and
>>>> SELinux patches that work together to isolate multiple guests' images
>>>> when they're stored in the same NFS mount. This results in an
>>>> environment where sVirt isolation and NFS image file isolation can both
>>>> be provided.
>>>
>>> Very nice. QEMU should use this to support privilege separation. We
>>> already have chroot and runas switches, a new switch should convert
>>> all file references to fd references internally for that process. If
>>> this can be made transparent, this should even be the default way of
>>> operation.
>>
>> You mean, QEMU starts up, opens all disk images, reinvokes itself in a
>> confined context, and then passes fds to the child?
>
> And exit after that, or do the same without forking.
>
> This wouldn't work now for the native CDROM devices which need to
> reopen the device. For that, an explicit reopen method could be added.
> The method could even chat with the privileged process to get that to
> do the reopening, but I'd leave that to libvirt and fail without it
> for plain QEMU.
There are more cases where we reopen the image file. One example is the
'commit' monitor command which temporarily reopens the backing file r/w.
Or Christoph's patch that allows guests to toggle the write-cache
enabled bit. Same for live snapshots. So we'll need a solution for them
before doing anything like this.
And breaking qemu without libvirt isn't really an option for me.
Kevin
- [Qemu-devel] [PATCH] Add support for fd: protocol, Corey Bryant, 2011/05/20
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Anthony Liguori, 2011/05/20
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Blue Swirl, 2011/05/20
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Anthony Liguori, 2011/05/20
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Blue Swirl, 2011/05/20
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol,
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Markus Armbruster, 2011/05/23
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Kevin Wolf, 2011/05/23
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Blue Swirl, 2011/05/23
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Anthony Liguori, 2011/05/23
- Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Corey Bryant, 2011/05/23
Re: [Qemu-devel] [PATCH] Add support for fd: protocol, Daniel P. Berrange, 2011/05/23