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. > --- > 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
