[PATCH v2 1/2] netfilter: nf_flow_table: reload ip{v6}h in nf_flow_nat_ip{v6}

From: Haishuang Yan
Date: Mon Mar 16 2020 - 22:03:40 EST


Since nf_flow_snat_port and nf_flow_snat_ip{v6} call pskb_may_pull()
which may change skb->data, so we need to reload ip{v6}h at the right
palce.

Fixes: a908fdec3dda ("netfilter: nf_flow_table: move ipv6 offload hook
code to nf_flow_table")
Fixes: 7d2086871762 ("netfilter: nf_flow_table: move ipv4 offload hook
code to nf_flow_table")
Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>
---
v2: collapse the patches
---
net/netfilter/nf_flow_table_ip.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 5272721..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;
@@ -417,11 +418,12 @@ static int nf_flow_nat_ipv6(const struct flow_offload *flow,

if (test_bit(NF_FLOW_SNAT, &flow->flags) &&
(nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
- nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
+ nf_flow_snat_ipv6(flow, skb, ipv6_hdr(skb), thoff, dir) < 0))
return -1;
+ ip6h = ipv6_hdr(skb);
if (test_bit(NF_FLOW_DNAT, &flow->flags) &&
(nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
- nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
+ nf_flow_dnat_ipv6(flow, skb, ipv6_hdr(skb), thoff, dir) < 0))
return -1;

return 0;
--
1.8.3.1