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

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Oct 15, 2026 at 01:19:22PM -0400, Willem de Bruijn wrote:
> 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;
> 
> Should this return 1, like the above?
> 
> Not sure whether the verify_header return value is well defined beyond
> just boolean.

                                header_check = vp->verify_header(
                                        vp->header_rxbuffer, skb, vp);

                              if (header_check < 0) {
                                        dev_kfree_skb_irq(skb);
                                        vp->dev->stats.rx_dropped++;
                                        vp->estats.rx_encaps_errors++;
                                        return 0;
                                }
                                if (header_check > 0) {
                                        vp->estats.rx_csum_offload_good++;
                                        skb->ip_summed = CHECKSUM_UNNECESSARY;
                                }


apparently? maybe i misunderstand.

-- 
MST