[PATCH AUTOSEL 4.19 320/671] netfilter: nft_flow_offload: add entry to flowtable after confirmation

Sasha Levin
2020-01-16T18:59:38Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 270a8a297f42ecff82060aaa53118361f09c1f7d ]

This is fixing flow offload for UDP traffic where packets only follow
one single direction.

The flow_offload_fixup_tcp() mechanism works fine in case that the
offloaded entry remains in SYN_RECV state, given sequence tracking is
reset and that conntrack handles syn+ack packets as a retransmission, ie.

sES + synack => sIG

for reply traffic.

Fixes: a3c90f7a2323 ("netfilter: nf_tables: flow offload expression")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_flow_offload.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 1ef8cb789c41..166edea0e452 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -103,8 +103,7 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
ct->status & IPS_SEQ_ADJUST)
goto out;

- if (ctinfo == IP_CT_NEW ||
- ctinfo == IP_CT_RELATED)
+ if (!nf_ct_is_confirmed(ct))
goto out;

if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
--
2.20.1