Re: [PATCH net-next v2 2/7] um: vector: honor virtio net hdr conversion failures

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2026-10-15 at 08:41 -0400, Michael S. Tsirkin wrote:
> virtio_net_hdr_to_skb() refuses packets whose checksum metadata
> it cannot make sense of, but the vector raw transport ignored
> its return value: rejected packets went on into the stack with
> their metadata unvalidated.
> 
> Propagate the failure.
> 
> Assisted-by: LLM
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  arch/um/drivers/vector_transports.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/um/drivers/vector_transports.c b/arch/um/drivers/vector_transports.c
> index e1fb2a76fdff..8b7548458663 100644
> --- a/arch/um/drivers/vector_transports.c
> +++ b/arch/um/drivers/vector_transports.c
> @@ -210,7 +210,9 @@ static int raw_verify_header(
>  		return 1;
>  
>  	skb_set_network_header(skb, ETH_HLEN);
> -	virtio_net_hdr_to_skb(skb, vheader, virtio_legacy_is_little_endian());
> +	if (virtio_net_hdr_to_skb(skb, vheader,
> +			virtio_legacy_is_little_endian()) < 0)
> +		return -1;
>  	return 0;
> 

Seems it'd be simpler to just

	return virtio_net_hdr_to_skb(...);

As far as I can tell, the function only returns -EINVAL or 0 (never a
positive value), and the caller only cares about negative (error) or
positive (no checksum needed), so that'd be equivalent?

johannes