Re: [PATCH v7 04/12] virtio-blk: Add validation for block size in config space

[Yongji Xie]

On Mon, May 17, 2021 at 5:56 PM Xie Yongji <xieyongji@xxxxxxxxxxxxx> wrote:
>
> This ensures that we will not use an invalid block size
> in config space (might come from an untrusted device).
>
> Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
> ---
>  drivers/block/virtio_blk.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index ebb4d3fe803f..c848aa36d49b 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -826,7 +826,7 @@ static int virtblk_probe(struct virtio_device *vdev)
>         err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
>                                    struct virtio_blk_config, blk_size,
>                                    &blk_size);
> -       if (!err)
> +       if (!err && blk_size > 0 && blk_size <= max_size)

The check here is incorrect. I will use PAGE_SIZE as the maximum
boundary in the new version.

Thanks,
Yongji