Re: [PATCH net-next v13 11/12] virtio_net: Add support for TCP and UDP ethtool rules

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

On Tue, Dec 02, 2025 at 03:55:39PM +0000, Simon Horman wrote:
> On Wed, Nov 26, 2025 at 01:35:38PM -0600, Daniel Jurgens wrote:
> 
> ...
> 
> > @@ -6005,6 +6085,11 @@ static void parse_ip4(struct iphdr *mask, struct iphdr *key,
> >  		mask->tos = l3_mask->tos;
> >  		key->tos = l3_val->tos;
> >  	}
> > +
> > +	if (l3_mask->proto) {
> > +		mask->protocol = l3_mask->proto;
> > +		key->protocol = l3_val->proto;
> > +	}
> >  }
> 
> Hi Daniel,
> 
> Claude Code with review-prompts flags an issue here,
> which I can't convince myself is not the case.
> 
> If parse_ip4() is called for a IP_USER_FLOW, which use ethtool_usrip4_spec,
> as does this function, then all is well.
> 
> However, it seems that it may also be called for TCP_V4_FLOW and UDP_V4_FLOW
> flows, in which case accessing .proto will overrun the mask and key which
> are actually struct ethtool_tcpip4_spec.
> 
> https://netdev-ai.bots.linux.dev/ai-review.html?id=51d97b85-5ca3-4cb8-a96a-0d6eab5e7196#patch-10


Oh I didn't know about this one. Is there any data on how does it work?
Which model/prompt/etc?


> >  
> >  static void parse_ip6(struct ipv6hdr *mask, struct ipv6hdr *key,
> > @@ -6022,16 +6107,35 @@ static void parse_ip6(struct ipv6hdr *mask, struct ipv6hdr *key,
> >  		memcpy(&mask->daddr, l3_mask->ip6dst, sizeof(mask->daddr));
> >  		memcpy(&key->daddr, l3_val->ip6dst, sizeof(key->daddr));
> >  	}
> > +
> > +	if (l3_mask->l4_proto) {
> > +		mask->nexthdr = l3_mask->l4_proto;
> > +		key->nexthdr = l3_val->l4_proto;
> > +	}
> 
> Likewise here.
> 
> >  }
> 
> ...