[PATCH AUTOSEL 4.4 42/65] vti6: flush x-netns xfrm cache when vti interface is removed

Sasha Levin
2018-10-25T14:18:17Z

From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

[ Upstream commit 7f92083eb58f85ea114d97f65fcbe22be5b0468d ]

This is the same fix than commit a5d0dc810abf ("vti: flush x-netns xfrm
cache when vti interface is removed")

This patch fixes a refcnt problem when a x-netns vti6 interface is removed:
unregister_netdevice: waiting for vti6_test to become free. Usage count = 1

Here is a script to reproduce the problem:

ip link set dev ntfp2 up
ip addr add dev ntfp2 2001::1/64
ip link add vti6_test type vti6 local 2001::1 remote 2001::2 key 1
ip netns add secure
ip link set vti6_test netns secure
ip netns exec secure ip link set vti6_test up
ip netns exec secure ip link s lo up
ip netns exec secure ip addr add dev vti6_test 2003::1/64
ip -6 xfrm policy add dir out tmpl src 2001::1 dst 2001::2 proto esp \
mode tunnel mark 1
ip -6 xfrm policy add dir in tmpl src 2001::2 dst 2001::1 proto esp \
mode tunnel mark 1
ip xfrm state add src 2001::1 dst 2001::2 proto esp spi 1 mode tunnel \
enc des3_ede 0x112233445566778811223344556677881122334455667788 mark 1
ip xfrm state add src 2001::2 dst 2001::1 proto esp spi 1 mode tunnel \
enc des3_ede 0x112233445566778811223344556677881122334455667788 mark 1
ip netns exec secure ping6 -c 4 2003::2
ip netns del secure

CC: Lance Richardson <lrichard@redhat.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Lance Richardson <lrichard@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/ip6_vti.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 60d4052d97a6..51da5987952c 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -1140,6 +1140,33 @@ static struct xfrm6_protocol vti_ipcomp6_protocol __read_mostly = {
.priority = 100,
};

+static bool is_vti6_tunnel(const struct net_device *dev)
+{
+ return dev->netdev_ops == &vti6_netdev_ops;
+}
+
+static int vti6_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct ip6_tnl *t = netdev_priv(dev);
+
+ if (!is_vti6_tunnel(dev))
+ return NOTIFY_DONE;
+
+ switch (event) {
+ case NETDEV_DOWN:
+ if (!net_eq(t->net, dev_net(dev)))
+ xfrm_garbage_collect(t->net);
+ break;
+ }
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block vti6_notifier_block __read_mostly = {
+ .notifier_call = vti6_device_event,
+};
+
/**
* vti6_tunnel_init - register protocol and reserve needed resources
*
@@ -1150,6 +1177,8 @@ static int __init vti6_tunnel_init(void)
const char *msg;
int err;

+ register_netdevice_notifier(&vti6_notifier_block);
+
msg = "tunnel device";
err = register_pernet_device(&vti6_net_ops);
if (err < 0)
@@ -1182,6 +1211,7 @@ static int __init vti6_tunnel_init(void)
xfrm_proto_esp_failed:
unregister_pernet_device(&vti6_net_ops);
pernet_dev_failed:
+ unregister_netdevice_notifier(&vti6_notifier_block);
pr_err("vti6 init: failed to register %s\n", msg);
return err;
}
@@ -1196,6 +1226,7 @@ static void __exit vti6_tunnel_cleanup(void)
xfrm6_protocol_deregister(&vti_ah6_protocol, IPPROTO_AH);
xfrm6_protocol_deregister(&vti_esp6_protocol, IPPROTO_ESP);
unregister_pernet_device(&vti6_net_ops);
+ unregister_netdevice_notifier(&vti6_notifier_block);
}

module_init(vti6_tunnel_init);
--
2.17.1