[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, 9 insertions, 6 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3982f13..406a493 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -384,15 +384,15 @@ static struct proto netlink_proto = {
 	.obj_size = sizeof(struct netlink_sock),
 };
 
-static int __netlink_create(struct socket *sock, struct mutex *cb_mutex,
-			    int protocol)
+static int __netlink_create(struct net *net, struct socket *sock,
+			    struct mutex *cb_mutex, int protocol)
 {
 	struct sock *sk;
 	struct netlink_sock *nlk;
 
 	sock->ops = &netlink_ops;
 
-	sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
+	sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
 	if (!sk)
 		return -ENOMEM;
 
@@ -412,13 +412,16 @@ static int __netlink_create(struct socket *sock, struct mutex *cb_mutex,
 	return 0;
 }
 
-static int netlink_create(struct socket *sock, int protocol)
+static int netlink_create(struct net *net, struct socket *sock, int protocol)
 {
 	struct module *module = NULL;
 	struct mutex *cb_mutex;
 	struct netlink_sock *nlk;
 	int err = 0;
 
+	if (net != &init_net)
+		return -EAFNOSUPPORT;
+
 	sock->state = SS_UNCONNECTED;
 
 	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
@@ -441,7 +444,7 @@ static int netlink_create(struct socket *sock, int protocol)
 	cb_mutex = nl_table[protocol].cb_mutex;
 	netlink_unlock_table();
 
-	if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0)
+	if ((err = __netlink_create(net, sock, cb_mutex, protocol)) < 0)
 		goto out_module;
 
 	nlk = nlk_sk(sock->sk);
@@ -1318,7 +1321,7 @@ netlink_kernel_create(int unit, unsigned int groups,
 	if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
 		return NULL;
 
-	if (__netlink_create(sock, cb_mutex, unit) < 0)
+	if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
 		goto out_sock_release;
 
 	if (groups < 32)