> > > > + > > > > + if (virtio_net_csum_partial_ok_at_offset(skb, gso_inner_type, > > > > inner_nh, > > > > + inner_proto)) > > > > + return 0; > > > > + > > > > + if (skb_is_gso(skb)) > > > > + return -EINVAL; > > > > This is a risk the commit message will have to call out. > > I tried with this: > > > > > We can't easily "complete the checksum" for GSO we don't > recognize - GSO > > > > assumes knowledge of the protocol. We could segment ignoring the > > > > checksum then do whatever csum_start and csum_offset say, but > that > > > > seems like an overkill for something that should happen. > > I guess I can add a more detailed explanation about what the risk is?
Let's just explicitly mention the consequence: non-standard GSO packets that previous would be sent may now fail. > > > I don't see a simple way around it. We discussed segmenting here too, > > but that requires intrusive changes to all callers too. > > Alternatively, > > > > 1. call segmentation, but only to see it remove the SKB_GSO_DODGY and > > thus verify that the TSO/USO packet is valid. Still drop otherwise. > > This also does not add overhead, because it would be called later > > anyway. > > > > 2. a failsafe off-by-default sysctl + static_branch that skips the > > drop when set. Messy, but so is the situation we're dealing with. > > Tack this on top or do you feel it's needed straight away. Not urgent. Can even wait until a report appears. But worth taking a look sooner if either of us gets around to it.
