Re: [PATCH] vdpa/mlx5: fix param validation in mlx5_vdpa_get_config()

[Eli Cohen]

On Mon, Feb 08, 2021 at 05:17:41PM +0100, Stefano Garzarella wrote:
> It's legal to have 'offset + len' equal to
> sizeof(struct virtio_net_config), since 'ndev->config' is a
> 'struct virtio_net_config', so we can safely copy its content under
> this condition.
> 
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

Acked-by: Eli Cohen <elic@xxxxxxxxxx>

BTW, same error in vdpa_sim you may want to fix.

> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index dc88559a8d49..10e9b09932eb 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1820,7 +1820,7 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
>  	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>  	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>  
> -	if (offset + len < sizeof(struct virtio_net_config))
> +	if (offset + len <= sizeof(struct virtio_net_config))
>  		memcpy(buf, (u8 *)&ndev->config + offset, len);
>  }
>  
> -- 
> 2.29.2
>