Subject: Re: [PATCH net] vhost: reject zero size iova range

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 9 Apr 2019 08:50:54 -0400

On Tue, Apr 09, 2019 at 12:10:25PM +0800, Jason Wang wrote:
> We used to accept zero size iova range which will lead a infinite loop
> in translate_desc(). Fixing this by failing the request in this case.
> 
> Reported-by: [email-masked]
> Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
> Signed-off-by: Jason Wang <[email-masked]>

Acked-by: Michael S. Tsirkin <[email-masked]>

Seems appropriate for stable.

> ---
>  drivers/vhost/vhost.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 5ace833de746..351af88231ad 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -911,8 +911,12 @@ static int vhost_new_umem_range(struct vhost_umem *umem,
>  				u64 start, u64 size, u64 end,
>  				u64 userspace_addr, int perm)
>  {
> -	struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
> +	struct vhost_umem_node *tmp, *node;
>  
> +	if (!size)
> +		return -EFAULT;
> +
> +	node = kmalloc(sizeof(*node), GFP_ATOMIC);
>  	if (!node)
>  		return -ENOMEM;
>  
> -- 
> 2.19.1