From 846a8da8c1e891ac0201a90739b8f3275bcf6e8f Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Mon, 14 Apr 2014 17:11:38 +0200 Subject: [PATCH] ip6_gre: don't allow to remove the fb_tunnel_dev [ Upstream commit 54d63f787b652755e66eb4dd8892ee6d3f5197fc ] 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 Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_gre.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index f3ffb43..2465d18 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1566,6 +1566,15 @@ static int ip6gre_changelink(struct net_device *dev, struct nlattr *tb[], 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 @@ -1643,6 +1652,7 @@ static struct rtnl_link_ops ip6gre_link_ops __read_mostly = { .validate = ip6gre_tunnel_validate, .newlink = ip6gre_newlink, .changelink = ip6gre_changelink, + .dellink = ip6gre_dellink, .get_size = ip6gre_get_size, .fill_info = ip6gre_fill_info, }; -- 2.7.4