[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, 12 insertions, 0 deletions

diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 204d4d6..b9b5d57 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -361,12 +361,16 @@ static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
 			     void *arg)
 {
+	struct net *net = skb->sk->sk_net;
 	struct ifaddrlblmsg *ifal;
 	struct nlattr *tb[IFAL_MAX+1];
 	struct in6_addr *pfx;
 	u32 label;
 	int err = 0;
 
+	if (net != &init_net)
+		return 0;
+
 	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 	if (err < 0)
 		return err;
@@ -445,11 +449,15 @@ static int ip6addrlbl_fill(struct sk_buff *skb,
 
 static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	struct net *net = skb->sk->sk_net;
 	struct ip6addrlbl_entry *p;
 	struct hlist_node *pos;
 	int idx = 0, s_idx = cb->args[0];
 	int err;
 
+	if (net != &init_net)
+		return 0;
+
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(p, pos, &ip6addrlbl_table.head, list) {
 		if (idx >= s_idx) {
@@ -479,6 +487,7 @@ static inline int ip6addrlbl_msgsize(void)
 static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 			  void *arg)
 {
+	struct net *net = in_skb->sk->sk_net;
 	struct ifaddrlblmsg *ifal;
 	struct nlattr *tb[IFAL_MAX+1];
 	struct in6_addr *addr;
@@ -487,6 +496,9 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 	struct ip6addrlbl_entry *p;
 	struct sk_buff *skb;
 
+	if (net != &init_net)
+		return 0;
+
 	err = nlmsg_parse(nlh, sizeof(*ifal), tb, IFAL_MAX, ifal_policy);
 	if (err < 0)
 		return err;