[PATCH AUTOSEL 4.9 05/29] netfilter: bridge: set skb transport_header before entering NF_INET_PRE_ROUTING

[Sasha Levin <sashal@kernel.org>]

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit e166e4fdaced850bee3d5ee12a5740258fb30587 ]

Since Commit 21d1196a35f5 ("ipv4: set transport header earlier"),
skb->transport_header has been always set before entering INET
netfilter. This patch is to set skb->transport_header for bridge
before entering INET netfilter by bridge-nf-call-iptables.

It also fixes an issue that sctp_error() couldn't compute a right
csum due to unset skb->transport_header.

Fixes: e6d8b64b34aa ("net: sctp: fix and consolidate SCTP checksumming code")
Reported-by: Li Shuang <shuali@redhat.com>
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
---
 net/bridge/br_netfilter_hooks.c | 1 +
 net/bridge/br_netfilter_ipv6.c  | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 38865deab3ac..0c96773d1829 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -512,6 +512,7 @@ static unsigned int br_nf_pre_routing(void *priv,
 	nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
 
 	skb->protocol = htons(ETH_P_IP);
+	skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
 
 	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 		skb->dev, NULL,
diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c
index a1b57cb07f1e..8c08dd07419f 100644
--- a/net/bridge/br_netfilter_ipv6.c
+++ b/net/bridge/br_netfilter_ipv6.c
@@ -235,6 +235,8 @@ unsigned int br_nf_pre_routing_ipv6(void *priv,
 	nf_bridge->ipv6_daddr = ipv6_hdr(skb)->daddr;
 
 	skb->protocol = htons(ETH_P_IPV6);
+	skb->transport_header = skb->network_header + sizeof(struct ipv6hdr);
+
 	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
 		skb->dev, NULL,
 		br_nf_pre_routing_finish_ipv6);
-- 
2.19.1