[PATCH 4.9 27/49] netfilter: conntrack: skip identical origin tuple in same zone only

Greg Kroah-Hartman
2021-02-22T13:48:50Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 07998281c268592963e1cd623fe6ab0270b65ae4 ]

The origin skip check needs to re-test the zone. Else, we might skip
a colliding tuple in the reply direction.

This only occurs when using 'directional zones' where origin tuples
reside in different zones but the reply tuples share the same zone.

This causes the new conntrack entry to be dropped at confirmation time
because NAT clash resolution was elided.

Fixes: 4e35c1cb9460240 ("netfilter: nf_nat: skip nat clash resolution for same-origin entries")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nf_conntrack_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index d507d0fc7858a..ddd90a3820d39 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -903,7 +903,8 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
* Let nf_ct_resolve_clash() deal with this later.
*/
if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
- &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple))
+ &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
+ nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
continue;

NF_CT_STAT_INC_ATOMIC(net, found);
--
2.27.0