[PATCH 5.4 348/411] netfilter: nat: really support inet nat without l3 address

Greg Kroah-Hartman
2022-06-13T11:42:22Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 282e5f8fe907dc3f2fbf9f2103b0e62ffc3a68a5 ]

When no l3 address is given, priv->family is set to NFPROTO_INET and
the evaluation function isn't called.

Call it too so l4-only rewrite can work.
Also add a test case for this.

Fixes: a33f387ecd5aa ("netfilter: nft_nat: allow to specify layer 4 protocol NAT only")
Reported-by: Yi Chen <yiche@redhat.com>
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/nft_nat.c | 3 +-
tools/testing/selftests/netfilter/nft_nat.sh | 43 ++++++++++++++++++++
2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c
index 17c0f75dfcdb..0c5bc3c37ecf 100644
--- a/net/netfilter/nft_nat.c
+++ b/net/netfilter/nft_nat.c
@@ -283,7 +283,8 @@ static void nft_nat_inet_eval(const struct nft_expr *expr,
{
const struct nft_nat *priv = nft_expr_priv(expr);

- if (priv->family == nft_pf(pkt))
+ if (priv->family == nft_pf(pkt) ||
+ priv->family == NFPROTO_INET)
nft_nat_eval(expr, regs, pkt);
}

diff --git a/tools/testing/selftests/netfilter/nft_nat.sh b/tools/testing/selftests/netfilter/nft_nat.sh
index d7e07f4c3d7f..4e15e8167310 100755
--- a/tools/testing/selftests/netfilter/nft_nat.sh
+++ b/tools/testing/selftests/netfilter/nft_nat.sh
@@ -374,6 +374,45 @@ EOF
return $lret
}

+test_local_dnat_portonly()
+{
+ local family=$1
+ local daddr=$2
+ local lret=0
+ local sr_s
+ local sr_r
+
+ip netns exec "$ns0" nft -f /dev/stdin <<EOF
+table $family nat {
+ chain output {
+ type nat hook output priority 0; policy accept;
+ meta l4proto tcp dnat to :2000
+
+ }
+}
+EOF
+ if [ $? -ne 0 ]; then
+ if [ $family = "inet" ];then
+ echo "SKIP: inet port test"
+ test_inet_nat=false
+ return
+ fi
+ echo "SKIP: Could not add $family dnat hook"
+ return
+ fi
+
+ echo SERVER-$family | ip netns exec "$ns1" timeout 5 socat -u STDIN TCP-LISTEN:2000 &
+ sc_s=$!
+
+ result=$(ip netns exec "$ns0" timeout 1 socat TCP:$daddr:2000 STDOUT)
+
+ if [ "$result" = "SERVER-inet" ];then
+ echo "PASS: inet port rewrite without l3 address"
+ else
+ echo "ERROR: inet port rewrite"
+ ret=1
+ fi
+}

test_masquerade6()
{
@@ -841,6 +880,10 @@ fi
reset_counters
test_local_dnat ip
test_local_dnat6 ip6
+
+reset_counters
+test_local_dnat_portonly inet 10.0.1.99
+
reset_counters
$test_inet_nat && test_local_dnat inet
$test_inet_nat && test_local_dnat6 inet
--
2.35.1