On Thu, Oct 14, 2021 at 1:45 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > On Thu, Oct 14, 2021 at 10:32:32AM +0800, Jason Wang wrote: > > On Wed, Oct 13, 2021 at 6:04 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > > > > > On Tue, Oct 12, 2021 at 02:52:16PM +0800, Jason Wang wrote: > > > > If an untrusted device neogitates BLK_F_MQ but advertises a zero > > > > 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 using single queue if num_queues is zero. > > > > > > > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > > > Cc: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > > > Cc: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > > > Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > > > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> > > > > > > I'd rather fail probe so we don't need to support that. > > > > I think we should be consistent among all virtio drivers. > > Well we started being permissive. We can't change that > since that might break on some hosts. But given focus on > security being restrictive sounds better now. Right. > > > E.g without this patch, we stick to 1 if virtio_create_feature() fail. > > Do we need to fix that? > > We can't easily, some hosts might be broken. Ok. Thanks > > > And we do something similar at least for the virtio-net and a lot of > > other places. > > > > /* We need at least 2 queue's */ > > if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN || > > max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX || > > !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > > max_queue_pairs = 1; > > > > Thanks > > > > > > > > > --- > > > > drivers/block/virtio_blk.c | 3 ++- > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > > > > index 9b3bd083b411..9deff01a38cb 100644 > > > > --- a/drivers/block/virtio_blk.c > > > > +++ b/drivers/block/virtio_blk.c > > > > @@ -495,7 +495,8 @@ static int init_vq(struct virtio_blk *vblk) > > > > err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, > > > > struct virtio_blk_config, num_queues, > > > > &num_vqs); > > > > - if (err) > > > > + /* We need at least one virtqueue */ > > > > + if (err || !num_vqs) > > > > num_vqs = 1; > > > > > > > > num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); > > > > -- > > > > 2.25.1 > > > > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
