linux-kernel - Re: [PATCH v3] virtio: reject shm region if length is zero

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Message-ID: <CACGkMEvw7GB1UtZtNjw4TVD1nzr2JCgdsjFK7tiGC46CLV8hPw@mail.gmail.com>
Date: Wed, 14 May 2025 14:08:12 +0800
From: Jason Wang <jasowang@...hat.com>
To: Sami Uddin <sami.md.ko@...il.com>
Cc: mst@...hat.com, xuanzhuo@...ux.alibaba.com, eperezma@...hat.com, 
	virtualization@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] virtio: reject shm region if length is zero

On Mon, May 12, 2025 at 6:22 AM Sami Uddin <sami.md.ko@...il.com> wrote:
>
> From: Sami Uddin <sami.md.ko@...il.com>
>
> Prevent usage of shared memory regions where the length is zero,
> as such configurations are not valid and may lead to unexpected behavior.
>
> Signed-off-by: Sami Uddin <sami.md.ko@...il.com>
> ---
> v3:
> - Use idiomatic 'if (!region->len)' as suggested by reviewer
> v2:
> - Fixed coding style issue: added space after 'if' statement
>
>  include/linux/virtio_config.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 169c7d367fac..b3e1d30c765b 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -329,6 +329,8 @@ static inline
>  bool virtio_get_shm_region(struct virtio_device *vdev,
>                            struct virtio_shm_region *region, u8 id)
>  {
> +       if (!region->len)
> +               return false;
>         if (!vdev->config->get_shm_region)
>                 return false;
>         return vdev->config->get_shm_region(vdev, region, id);
> --
> 2.34.1
>

Acked-by: Jason Wang <jasowang@...hat.com>

Thanks