Re: [PATCH 1/9] virtio-blk: validate num_queues during probe

[Jason Wang]

在 2021/9/13 下午3:48, Stefano Garzarella 写道:
> On Mon, Sep 13, 2021 at 01:53:45PM +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>
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > ---
> > 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 e574fbf5e6df..f130d12df4b9 100644
> > --- a/drivers/block/virtio_blk.c
> > +++ b/drivers/block/virtio_blk.c
> > @@ -498,7 +498,8 @@ 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 on virtqueue */
>
> s/on/one/
>
> The rest LGTM.
>
> Stefano


Will fix in next version.

Thanks


> > +    if (err || !num_vqs)
> >         num_vqs = 1;
> >
> >     num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs);
> > --
> > 2.25.1
> >
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