[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, 8 insertions, 5 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2386090c3a1..10e73122c34 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -594,7 +594,7 @@ static struct proto unix_proto = {
  */
 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
 
-static struct sock * unix_create1(struct socket *sock)
+static struct sock * unix_create1(struct net *net, struct socket *sock)
 {
 	struct sock *sk = NULL;
 	struct unix_sock *u;
@@ -602,7 +602,7 @@ static struct sock * unix_create1(struct socket *sock)
 	if (atomic_read(&unix_nr_socks) >= 2*get_max_files())
 		goto out;
 
-	sk = sk_alloc(PF_UNIX, GFP_KERNEL, &unix_proto, 1);
+	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, 1);
 	if (!sk)
 		goto out;
 
@@ -628,8 +628,11 @@ out:
 	return sk;
 }
 
-static int unix_create(struct socket *sock, int protocol)
+static int unix_create(struct net *net, struct socket *sock, int protocol)
 {
+	if (net != &init_net)
+		return -EAFNOSUPPORT;
+
 	if (protocol && protocol != PF_UNIX)
 		return -EPROTONOSUPPORT;
 
@@ -655,7 +658,7 @@ static int unix_create(struct socket *sock, int protocol)
 		return -ESOCKTNOSUPPORT;
 	}
 
-	return unix_create1(sock) ? 0 : -ENOMEM;
+	return unix_create1(net, sock) ? 0 : -ENOMEM;
 }
 
 static int unix_release(struct socket *sock)
@@ -1039,7 +1042,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 	err = -ENOMEM;
 
 	/* create new sock for complete connection */
-	newsk = unix_create1(NULL);
+	newsk = unix_create1(sk->sk_net, NULL);
 	if (newsk == NULL)
 		goto out;