netdev - [PATCH 2/4] netfilter: nf_flow_table: reload iph in nf_flow_nat

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Date:   Sun, 15 Mar 2020 22:15:03 +0800
From:   Haishuang Yan <yanhaishuang@...s.chinamobile.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>
Cc:     netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Haishuang Yan <yanhaishuang@...s.chinamobile.com>
Subject: [PATCH 2/4] netfilter: nf_flow_table: reload iph in nf_flow_nat_ip

Since nf_flow_snat_port and nf_flow_snat_ip call pskb_may_pull()
which may change skb->data, so we need to reload iph at the right
place.

Fixes: 7d2086871762 ("netfilter: nf_flow_table: move ipv4 offload hook
code to nf_flow_table")
Signed-off-by: Haishuang Yan <yanhaishuang@...s.chinamobile.com>
---
 net/netfilter/nf_flow_table_ip.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 2e6ebbe..942bda5 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -146,11 +146,12 @@ static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
 
 	if (test_bit(NF_FLOW_SNAT, &flow->flags) &&
 	    (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
-	     nf_flow_snat_ip(flow, skb, iph, thoff, dir) < 0))
+	     nf_flow_snat_ip(flow, skb, ip_hdr(skb), thoff, dir) < 0))
 		return -1;
+	iph = ip_hdr(skb);
 	if (test_bit(NF_FLOW_DNAT, &flow->flags) &&
 	    (nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
-	     nf_flow_dnat_ip(flow, skb, iph, thoff, dir) < 0))
+	     nf_flow_dnat_ip(flow, skb, ip_hdr(skb), thoff, dir) < 0))
 		return -1;
 
 	return 0;
-- 
1.8.3.1