rtnetlink: release net refcnt on error in do_setlink()

rtnl_link_get_net() holds a reference on the 'struct net', we need to release
it in case of error.

CC: Eric W. Biederman <ebiederm@xmission.com>
Fixes: b51642f6d77b ("net: Enable a userns root rtnl calls that are safe for unprivilged users")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index b9b7dfaf202b..76321ea442c3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1498,6 +1498,7 @@ static int do_setlink(const struct sk_buff *skb,
                         goto errout;
                 }
                 if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
+                        put_net(net);
                         err = -EPERM;
                         goto errout;
                 }