ip6_gre: don't allow to remove the fb_tunnel_dev
It's possible to remove the FB tunnel with the command 'ip link del ip6gre0' but
this is unsafe, the module always supposes that this device exists. For example,
ip6gre_tunnel_lookup() may use it unconditionally.
Let's add a rtnl handler for dellink, which will never remove the FB tunnel (we
let ip6gre_destroy_tunnels() do the job).
Introduced by commit c12b395a4664 ("gre: Support GRE over IPv6").
CC: Dmitry Kozlov <xeb@mail.ru>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index c98338b..9d92146 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1559,6 +1559,15 @@
return 0;
}
+static void ip6gre_dellink(struct net_device *dev, struct list_head *head)
+{
+ struct net *net = dev_net(dev);
+ struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
+
+ if (dev != ign->fb_tunnel_dev)
+ unregister_netdevice_queue(dev, head);
+}
+
static size_t ip6gre_get_size(const struct net_device *dev)
{
return
@@ -1636,6 +1645,7 @@
.validate = ip6gre_tunnel_validate,
.newlink = ip6gre_newlink,
.changelink = ip6gre_changelink,
+ .dellink = ip6gre_dellink,
.get_size = ip6gre_get_size,
.fill_info = ip6gre_fill_info,
};