netdev - Re: [PATCH nf-next 5/6] netfilter: use nf_ip6_check_hbh_len in nf_ct_skb_network

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Date:   Tue, 7 Mar 2023 15:58:51 -0500
From:   Xin Long <lucien.xin@...il.com>
To:     Simon Horman <simon.horman@...igine.com>
Cc:     netfilter-devel@...r.kernel.org,
        network dev <netdev@...r.kernel.org>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>, davem@...emloft.net,
        kuba@...nel.org, Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Pravin B Shelar <pshelar@....org>,
        Aaron Conole <aconole@...hat.com>
Subject: Re: [PATCH nf-next 5/6] netfilter: use nf_ip6_check_hbh_len in nf_ct_skb_network_trim

On Mon, Mar 6, 2023 at 11:35 AM Simon Horman <simon.horman@...igine.com> wrote:
>
> On Fri, Mar 03, 2023 at 07:12:41PM -0500, Xin Long wrote:
> > For IPv6 Jumbo packets, the ipv6_hdr(skb)->payload_len is always 0,
> > and its real payload_len ( > 65535) is saved in hbh exthdr. With 0
> > length for the jumbo packets, all data and exthdr will be trimmed
> > in nf_ct_skb_network_trim().
> >
> > This patch is to call nf_ip6_check_hbh_len() to get real pkt_len
> > of the IPv6 packet, similar to br_validate_ipv6().
> >
> > Signed-off-by: Xin Long <lucien.xin@...il.com>
>
> Reviewed-by: Simon Horman <simon.horman@...igine.com>
>
> ...
>
> > diff --git a/net/netfilter/nf_conntrack_ovs.c b/net/netfilter/nf_conntrack_ovs.c
> > index 52b776bdf526..2016a3b05f86 100644
> > --- a/net/netfilter/nf_conntrack_ovs.c
> > +++ b/net/netfilter/nf_conntrack_ovs.c
>
> ...
>
> > @@ -114,14 +115,20 @@ EXPORT_SYMBOL_GPL(nf_ct_add_helper);
> >  int nf_ct_skb_network_trim(struct sk_buff *skb, int family)
> >  {
> >       unsigned int len;
> > +     int err;
> >
> >       switch (family) {
> >       case NFPROTO_IPV4:
> >               len = skb_ip_totlen(skb);
> >               break;
> >       case NFPROTO_IPV6:
> > -             len = sizeof(struct ipv6hdr)
> > -                     + ntohs(ipv6_hdr(skb)->payload_len);
> > +             len = ntohs(ipv6_hdr(skb)->payload_len);
> > +             if (ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP) {
>
> nit: if you spin a v2,
>      you may consider reducing the scope of err to this block.
>
Hi, Simon,

I will post v2 with your suggestions including those in another 3 patches. :)

Thanks.

> > +                     err = nf_ip6_check_hbh_len(skb, &len);
> > +                     if (err)
> > +                             return err;
> > +             }
> > +             len += sizeof(struct ipv6hdr);
> >               break;
> >       default:
> >               len = skb->len;
> > --
> > 2.39.1
> >