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SubjectRe: [PATCH 1/9] virtio-blk: validate num_queues during probe
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@redhat.com>
>Cc: Stefan Hajnoczi <stefanha@redhat.com>
>Signed-off-by: Jason Wang <jasowang@redhat.com>
>---
> 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

>+ 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@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/virtualization
>

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