[NET]: Make socket creation namespace safe.

This patch passes in the namespace a new socket should be created in
and has the socket code do the appropriate reference counting.  By
virtue of this all socket create methods are touched.  In addition
the socket create methods are modified so that they will fail if
you attempt to create a socket in a non-default network namespace.

Failing if we attempt to create a socket outside of the default
network namespace ensures that as we incrementally make the network stack
network namespace aware we will not export functionality that someone
has not audited and made certain is network namespace safe.
Allowing us to partially enable network namespaces before all of the
exotic protocols are supported.

Any protocol layers I have missed will fail to compile because I now
pass an extra parameter into the socket creation code.

[ Integrated AF_IUCV build fixes from Andrew Morton... -DaveM ]

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index bbc726a49d8..a31455dc702 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -873,7 +873,7 @@ static inline void sock_lock_init(struct sock *sk)
  *      @prot: struct proto associated with this new sock instance
  *      @zero_it: if we should zero the newly allocated sock
  */
-struct sock *sk_alloc(int family, gfp_t priority,
+struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
                       struct proto *prot, int zero_it)
 {
         struct sock *sk = NULL;
@@ -894,6 +894,7 @@ struct sock *sk_alloc(int family, gfp_t priority,
                          */
                         sk->sk_prot = sk->sk_prot_creator = prot;
                         sock_lock_init(sk);
+                        sk->sk_net = get_net(net);
                 }
 
                 if (security_sk_alloc(sk, family, priority))
@@ -933,6 +934,7 @@ void sk_free(struct sock *sk)
                        __FUNCTION__, atomic_read(&sk->sk_omem_alloc));
 
         security_sk_free(sk);
+        put_net(sk->sk_net);
         if (sk->sk_prot_creator->slab != NULL)
                 kmem_cache_free(sk->sk_prot_creator->slab, sk);
         else
@@ -942,7 +944,7 @@ void sk_free(struct sock *sk)
 
 struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
 {
-        struct sock *newsk = sk_alloc(sk->sk_family, priority, sk->sk_prot, 0);
+        struct sock *newsk = sk_alloc(sk->sk_net, sk->sk_family, priority, sk->sk_prot, 0);
 
         if (newsk != NULL) {
                 struct sk_filter *filter;