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

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Message-Id: <5411027934a79f0430edb905ad4b434ec6b8396e.1677888566.git.lucien.xin@gmail.com>
Date:   Fri,  3 Mar 2023 19:12:41 -0500
From:   Xin Long <lucien.xin@...il.com>
To:     netfilter-devel@...r.kernel.org,
        network dev <netdev@...r.kernel.org>
Cc:     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: [PATCH nf-next 5/6] netfilter: use nf_ip6_check_hbh_len in nf_ct_skb_network_trim

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>
---
 net/netfilter/nf_conntrack_ovs.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

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
@@ -6,6 +6,7 @@
 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
 #include <net/ipv6_frag.h>
 #include <net/ip.h>
+#include <linux/netfilter_ipv6.h>
 
 /* 'skb' should already be pulled to nh_ofs. */
 int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
@@ -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) {
+			err = nf_ip6_check_hbh_len(skb, &len);
+			if (err)
+				return err;
+		}
+		len += sizeof(struct ipv6hdr);
 		break;
 	default:
 		len = skb->len;
-- 
2.39.1