[NET]: Modify all rtnetlink methods to only work in the initial namespace (v2)

Before I can enable rtnetlink to work in all network namespaces I need
to be certain that something won't break.  So this patch deliberately
disables all of the rtnletlink methods in everything except the
initial network namespace.  After the methods have been audited this
extra check can be disabled.

Changes from v1:
- added IPv6 addrlabel protection

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 10 insertions, 0 deletions

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 72cdb0f..8528291 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -18,6 +18,8 @@
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/kmod.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
 #include <net/sch_generic.h>
 #include <net/act_api.h>
 #include <net/netlink.h>
@@ -924,10 +926,14 @@ done:
 
 static int tc_ctl_action(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 {
+	struct net *net = skb->sk->sk_net;
 	struct rtattr **tca = arg;
 	u32 pid = skb ? NETLINK_CB(skb).pid : 0;
 	int ret = 0, ovr = 0;
 
+	if (net != &init_net)
+		return -EINVAL;
+
 	if (tca[TCA_ACT_TAB-1] == NULL) {
 		printk("tc_ctl_action: received NO action attribs\n");
 		return -EINVAL;
@@ -997,6 +1003,7 @@ find_dump_kind(struct nlmsghdr *n)
 static int
 tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	struct net *net = skb->sk->sk_net;
 	struct nlmsghdr *nlh;
 	unsigned char *b = skb_tail_pointer(skb);
 	struct rtattr *x;
@@ -1006,6 +1013,9 @@ tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
 	struct tcamsg *t = (struct tcamsg *) NLMSG_DATA(cb->nlh);
 	struct rtattr *kind = find_dump_kind(cb->nlh);
 
+	if (net != &init_net)
+		return 0;
+
 	if (kind == NULL) {
 		printk("tc_dump_action: action bad kind\n");
 		return 0;