ipv4: Disallow non-namespace aware protocols to register.

All in-tree ipv4 protocol implementations are now namespace
aware.  Therefore all the run-time checks are superfluous.

Reject registry of any non-namespace aware ipv4 protocol.
Eventually we'll remove prot->netns_ok and this registry
time check as well.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 6 insertions, 26 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 49ddca31c4da..1aec92bf8018 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -263,21 +263,6 @@ void build_ehash_secret(void)
 }
 EXPORT_SYMBOL(build_ehash_secret);
 
-static inline int inet_netns_ok(struct net *net, __u8 protocol)
-{
-        const struct net_protocol *ipprot;
-
-        if (net_eq(net, &init_net))
-                return 1;
-
-        ipprot = rcu_dereference(inet_protos[protocol]);
-        if (ipprot == NULL) {
-                /* raw IP is OK */
-                return 1;
-        }
-        return ipprot->netns_ok;
-}
-
 /*
  *      Create an inet socket.
  */
@@ -350,10 +335,6 @@ lookup_protocol:
             !ns_capable(net->user_ns, CAP_NET_RAW))
                 goto out_rcu_unlock;
 
-        err = -EAFNOSUPPORT;
-        if (!inet_netns_ok(net, protocol))
-                goto out_rcu_unlock;
-
         sock->ops = answer->ops;
         answer_prot = answer->prot;
         answer_no_check = answer->no_check;
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index f1395a6fb35f..87abd3e2bd32 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -208,13 +208,6 @@ static int ip_local_deliver_finish(struct sk_buff *skb)
                 if (ipprot != NULL) {
                         int ret;
 
-                        if (!net_eq(net, &init_net) && !ipprot->netns_ok) {
-                                net_info_ratelimited("%s: proto %d isn't netns-ready\n",
-                                                     __func__, protocol);
-                                kfree_skb(skb);
-                                goto out;
-                        }
-
                         if (!ipprot->no_policy) {
                                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
                                         kfree_skb(skb);
diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c
index 0f9d09f54bd9..ce848461acbb 100644
--- a/net/ipv4/protocol.c
+++ b/net/ipv4/protocol.c
@@ -37,6 +37,12 @@ const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
 
 int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
 {
+        if (!prot->netns_ok) {
+                pr_err("Protocol %u is not namespace aware, cannot register.\n",
+                        protocol);
+                return -EINVAL;
+        }
+
         return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
                         NULL, prot) ? 0 : -1;
 }