[libvirt] [PATCH] libvirt no longer supports qemu format=host_device

[Daniel P. Berrange]

On Fri, Nov 05, 2010 at 02:04:50PM -0500, Jamie Strandboge wrote:
> Bug: https://launchpad.net/bugs/665531
> 
> The fixes for CVE-2010-2237, CVE-2010-2238 and CVE-2010-2239 broke
> format=host_device for the qemu driver. Qemu's host_device is used to
> specify raw files that don't have holes, so we need to treat <driver
> name='qemu' type='host_device'/> as raw in virDomainDiskDefForeachPath()
> (like we do for 'aio'). For example, the following xml is no longer
> valid, but should be:
> 
>     <disk type='file' device='disk'>
>       <driver name='qemu' type='host_device'/>
>       <source file='/tmp/foo.img'/>
>       <target dev='hda' bus='ide'/>
>     </disk>
> 
> This is confirmed as not working on 0.8.3 and 0.8.5. The attached patch
> against 0.8.5 fixes the issue and restores host_device support.

host_device is not a data format type, but rather a qemu driver protocol.
As such it is not applicable for the <driver type=XXX> field, because
the protocol is already specified at the <disk> element level with
a combo of the type+device fields. If it happened to be possible to
set it in the <driver>  field that is just pure chance & not something
that is supported. If we need to setup host_device anywhere, then this
needs to be dealt with at the qemu_conf.c where we generate the CLI
args.  

Regards,
Daniel
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