diff mbox series

[SRU,Jammy,v2,2/2] act_mirred: use the backlog for nested calls to mirred ingress

Message ID 20230512180139.27507-4-yuxuan.luo@canonical.com
State New
Headers show
Series None | expand

Commit Message

Yuxuan Luo May 12, 2023, 6:01 p.m. UTC 
From: Davide Caratti <dcaratti@redhat.com>

William reports kernel soft-lockups on some OVS topologies when TC mirred
egress->ingress action is hit by local TCP traffic [1].
The same can also be reproduced with SCTP (thanks Xin for verifying), when
client and server reach themselves through mirred egress to ingress, and
one of the two peers sends a "heartbeat" packet (from within a timer).

Enqueueing to backlog proved to fix this soft lockup; however, as Cong
noticed [2], we should preserve - when possible - the current mirred
behavior that counts as "overlimits" any eventual packet drop subsequent to
the mirred forwarding action [3]. A compromise solution might use the
backlog only when tcf_mirred_act() has a nest level greater than one:
change tcf_mirred_forward() accordingly.

Also, add a kselftest that can reproduce the lockup and verifies TC mirred
ability to account for further packet drops after TC mirred egress->ingress
(when the nest level is 1).

 [1] https://lore.kernel.org/netdev/33dc43f587ec1388ba456b4915c75f02a8aae226.1663945716.git.dcaratti@redhat.com/
 [2] https://lore.kernel.org/netdev/Y0w%2FWWY60gqrtGLp@pop-os.localdomain/
 [3] such behavior is not guaranteed: for example, if RPS or skb RX
     timestamping is enabled on the mirred target device, the kernel
     can defer receiving the skb and return NET_RX_SUCCESS inside
     tcf_mirred_forward().

Reported-by: William Zhao <wizhao@redhat.com>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
(backported from commit ca22da2fbd693b54dc8e3b7b54ccc9f7e9ba3640)
[yuxuan.luo: add mirred_egress_to_ingress_tcp_test to tc_actions.sh only]
CVE-2022-4269
Signed-off-by: Yuxuan Luo <yuxuan.luo@canonical.com>
---
 net/sched/act_mirred.c                        |  7 ++
 .../selftests/net/forwarding/tc_actions.sh    | 95 ++++++++++++++++++-
 2 files changed, 101 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index b28d49495de09..6f39789d9d14b 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -204,12 +204,19 @@  static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	return err;
 }
 
+static bool is_mirred_nested(void)
+{
+	return unlikely(__this_cpu_read(mirred_nest_level) > 1);
+}
+
 static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb)
 {
 	int err;
 
 	if (!want_ingress)
 		err = tcf_dev_queue_xmit(skb, dev_queue_xmit);
+	else if (is_mirred_nested())
+		err = netif_rx(skb);
 	else
 		err = netif_receive_skb(skb);
 
diff --git a/tools/testing/selftests/net/forwarding/tc_actions.sh b/tools/testing/selftests/net/forwarding/tc_actions.sh
index d9eca227136bb..3b6db2bf16027 100755
--- a/tools/testing/selftests/net/forwarding/tc_actions.sh
+++ b/tools/testing/selftests/net/forwarding/tc_actions.sh
@@ -3,7 +3,8 @@ 
 
 ALL_TESTS="gact_drop_and_ok_test mirred_egress_redirect_test \
 	mirred_egress_mirror_test matchall_mirred_egress_mirror_test \
-	gact_trap_test"
+	gact_trap_test \
+	mirred_egress_to_ingress_tcp_test"
 NUM_NETIFS=4
 source tc_common.sh
 source lib.sh
@@ -153,6 +154,98 @@  gact_trap_test()
 	log_test "trap ($tcflags)"
 }
 
+<<<<<<< HEAD
+=======
+mirred_egress_to_ingress_test()
+{
+	RET=0
+
+	tc filter add dev $h1 protocol ip pref 100 handle 100 egress flower \
+		ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 8 action \
+			ct commit nat src addr 192.0.2.2 pipe \
+			ct clear pipe \
+			ct commit nat dst addr 192.0.2.1 pipe \
+			mirred ingress redirect dev $h1
+
+	tc filter add dev $swp1 protocol ip pref 11 handle 111 ingress flower \
+		ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 8 action drop
+	tc filter add dev $swp1 protocol ip pref 12 handle 112 ingress flower \
+		ip_proto icmp src_ip 192.0.2.1 dst_ip 192.0.2.2 type 0 action pass
+
+	$MZ $h1 -c 1 -p 64 -a $h1mac -b $h2mac -A 192.0.2.1 -B 192.0.2.2 \
+		-t icmp "ping,id=42,seq=10" -q
+
+	tc_check_packets "dev $h1 egress" 100 1
+	check_err $? "didn't mirror first packet"
+
+	tc_check_packets "dev $swp1 ingress" 111 1
+	check_fail $? "didn't redirect first packet"
+	tc_check_packets "dev $swp1 ingress" 112 1
+	check_err $? "didn't receive reply to first packet"
+
+	ping 192.0.2.2 -I$h1 -c1 -w1 -q 1>/dev/null 2>&1
+
+	tc_check_packets "dev $h1 egress" 100 2
+	check_err $? "didn't mirror second packet"
+	tc_check_packets "dev $swp1 ingress" 111 1
+	check_fail $? "didn't redirect second packet"
+	tc_check_packets "dev $swp1 ingress" 112 2
+	check_err $? "didn't receive reply to second packet"
+
+	tc filter del dev $h1 egress protocol ip pref 100 handle 100 flower
+	tc filter del dev $swp1 ingress protocol ip pref 11 handle 111 flower
+	tc filter del dev $swp1 ingress protocol ip pref 12 handle 112 flower
+
+	log_test "mirred_egress_to_ingress ($tcflags)"
+}
+
+mirred_egress_to_ingress_tcp_test()
+{
+	local tmpfile=$(mktemp) tmpfile1=$(mktemp)
+
+	RET=0
+	dd conv=sparse status=none if=/dev/zero bs=1M count=2 of=$tmpfile
+	tc filter add dev $h1 protocol ip pref 100 handle 100 egress flower \
+		$tcflags ip_proto tcp src_ip 192.0.2.1 dst_ip 192.0.2.2 \
+			action ct commit nat src addr 192.0.2.2 pipe \
+			action ct clear pipe \
+			action ct commit nat dst addr 192.0.2.1 pipe \
+			action ct clear pipe \
+			action skbedit ptype host pipe \
+			action mirred ingress redirect dev $h1
+	tc filter add dev $h1 protocol ip pref 101 handle 101 egress flower \
+		$tcflags ip_proto icmp \
+			action mirred ingress redirect dev $h1
+	tc filter add dev $h1 protocol ip pref 102 handle 102 ingress flower \
+		ip_proto icmp \
+			action drop
+
+	ip vrf exec v$h1 nc --recv-only -w10 -l -p 12345 -o $tmpfile1  &
+	local rpid=$!
+	ip vrf exec v$h1 nc -w1 --send-only 192.0.2.2 12345 <$tmpfile
+	wait -n $rpid
+	cmp -s $tmpfile $tmpfile1
+	check_err $? "server output check failed"
+
+	$MZ $h1 -c 10 -p 64 -a $h1mac -b $h1mac -A 192.0.2.1 -B 192.0.2.1 \
+		-t icmp "ping,id=42,seq=5" -q
+	tc_check_packets "dev $h1 egress" 101 10
+	check_err $? "didn't mirred redirect ICMP"
+	tc_check_packets "dev $h1 ingress" 102 10
+	check_err $? "didn't drop mirred ICMP"
+	local overlimits=$(tc_rule_stats_get ${h1} 101 egress .overlimits)
+	test ${overlimits} = 10
+	check_err $? "wrong overlimits, expected 10 got ${overlimits}"
+
+	tc filter del dev $h1 egress protocol ip pref 100 handle 100 flower
+	tc filter del dev $h1 egress protocol ip pref 101 handle 101 flower
+	tc filter del dev $h1 ingress protocol ip pref 102 handle 102 flower
+
+	rm -f $tmpfile $tmpfile1
+	log_test "mirred_egress_to_ingress_tcp ($tcflags)"
+}
+
+>>>>>>> ca22da2fbd693 (act_mirred: use the backlog for nested calls to mirred ingress)
 setup_prepare()
 {
 	h1=${NETIFS[p1]}