Re: [PATCH V3 01/10] virtio-blk: validate num_queues during probe

[Michael S. Tsirkin]

On Wed, Oct 20, 2021 at 09:18:17AM +0200, Stefano Garzarella wrote:
> On Tue, Oct 19, 2021 at 03:01:43PM +0800, Jason Wang wrote:
> > If an untrusted device neogitates BLK_F_MQ but advertises a zero
> 
> s/neogitates/negotiates
> 
> > num_queues, the driver may end up trying to allocating zero size
> > buffers where ZERO_SIZE_PTR is returned which may pass the checking
> > against the NULL. This will lead unexpected results.
> > 
> > Fixing this by failing the probe in this case.
> > 
> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > Cc: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
> > Cc: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> > drivers/block/virtio_blk.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> 
> Should we CC stable?
> 
> Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

No IMO - I don't think we can reasonably expect stable to become
protected against attacks on encrypted guests. That's
a new feature, not a bugfix.

-- 
MST