From: "Jason A. Donenfeld" Jason@zx2c4.com

[ Upstream commit af8afcf1fdd5f365f70e2386c2d8c7a1abd853d7 ]

If netfilter changes the packet mark, the packet is rerouted. The ip_route_me_harder family of functions fails to use the right sk, opting to instead use skb->sk, resulting in a routing loop when used with tunnels. With the next change fixing this issue in netfilter, test for the relevant condition inside our test suite, since wireguard was where the bug was discovered.

Reported-by: Chen Minqiang ptpt52@gmail.com Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/wireguard/netns.sh | 8 ++++++++ tools/testing/selftests/wireguard/qemu/kernel.config | 2 ++ 2 files changed, 10 insertions(+)

diff --git a/tools/testing/selftests/wireguard/netns.sh b/tools/testing/selftests/wireguard/netns.sh index d77f4829f1e07..74c69b75f6f5a 100755 --- a/tools/testing/selftests/wireguard/netns.sh +++ b/tools/testing/selftests/wireguard/netns.sh @@ -316,6 +316,14 @@ pp sleep 3 n2 ping -W 1 -c 1 192.168.241.1 n1 wg set wg0 peer "$pub2" persistent-keepalive 0

+# Test that sk_bound_dev_if works +n1 ping -I wg0 -c 1 -W 1 192.168.241.2 +# What about when the mark changes and the packet must be rerouted? +n1 iptables -t mangle -I OUTPUT -j MARK --set-xmark 1 +n1 ping -c 1 -W 1 192.168.241.2 # First the boring case +n1 ping -I wg0 -c 1 -W 1 192.168.241.2 # Then the sk_bound_dev_if case +n1 iptables -t mangle -D OUTPUT -j MARK --set-xmark 1 + # Test that onion routing works, even when it loops n1 wg set wg0 peer "$pub3" allowed-ips 192.168.242.2/32 endpoint 192.168.241.2:5 ip1 addr add 192.168.242.1/24 dev wg0 diff --git a/tools/testing/selftests/wireguard/qemu/kernel.config b/tools/testing/selftests/wireguard/qemu/kernel.config index d531de13c95b0..4eecb432a66c1 100644 --- a/tools/testing/selftests/wireguard/qemu/kernel.config +++ b/tools/testing/selftests/wireguard/qemu/kernel.config @@ -18,10 +18,12 @@ CONFIG_NF_NAT=y CONFIG_NETFILTER_XTABLES=y CONFIG_NETFILTER_XT_NAT=y CONFIG_NETFILTER_XT_MATCH_LENGTH=y +CONFIG_NETFILTER_XT_MARK=y CONFIG_NF_CONNTRACK_IPV4=y CONFIG_NF_NAT_IPV4=y CONFIG_IP_NF_IPTABLES=y CONFIG_IP_NF_FILTER=y +CONFIG_IP_NF_MANGLE=y CONFIG_IP_NF_NAT=y CONFIG_IP_ADVANCED_ROUTER=y CONFIG_IP_MULTIPLE_TABLES=y