[libvirt] [PATCH 2/2] domain_conf: allow CDROM/Floppy media change with attach-device

[Michal Privoznik]

On 4/10/19 11:49 PM, Daniel Henrique Barboza wrote:
> Commit f1d6585300 ("domain_conf: check device address before attach")
> added an address verification for all devices, avoiding calling
> the driver attach() for a case in which we know that the device
> would have duplicated address.
> 
> That commit failed to contemplate the case of CDROM/Floppy devices
> that can change and eject media using attach-device, an usage
> that is also covered by this command. This patch adds an
> extra condition for the added address verification code,
> allowing CDROM/Floppy devices to bypass it.
> 
> Fixes: f1d6585300001c7b23b8796a0faa4411c3531996
> Reported-by: Jim Fehlig <jfehlig at suse.com>
> Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
> ---
>   src/conf/domain_conf.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index b6be1e730d..f65a335d86 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -28597,6 +28597,7 @@ virDomainDefCompatibleDevice(virDomainDefPtr def,
>       if (action == VIR_DOMAIN_DEVICE_ACTION_ATTACH &&
>           data.newInfo &&
>           data.newInfo->type != VIR_DOMAIN_DEVICE_ADDRESS_TYPE_NONE &&
> +        !virDomainDiskIsCdromOrFloppy(dev->data.disk) &&

This is unsafe. You can't access dev->data.* unless you check dev->type 
because @data is a union.

I'm testing a different approach. Will post patches shortly.

Michal