tipc: correctly handle releasing a not fully initialized sock

Commit f2f9800d4955 "tipc: make tipc node table aware of net
namespace" has added a dereference of sock->sk before making sure it's
not NULL, which makes releasing a tipc socket NULL pointer dereference
for sockets that are not fully initialized.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index c9c34a667921..720fda6cc2e6 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -470,8 +470,8 @@ static void tipc_sk_callback(struct rcu_head *head)
 static int tipc_release(struct socket *sock)
 {
         struct sock *sk = sock->sk;
-        struct net *net = sock_net(sk);
-        struct tipc_net *tn = net_generic(net, tipc_net_id);
+        struct net *net;
+        struct tipc_net *tn;
         struct tipc_sock *tsk;
         struct sk_buff *skb;
         u32 dnode, probing_state;
@@ -483,6 +483,9 @@ static int tipc_release(struct socket *sock)
         if (sk == NULL)
                 return 0;
 
+        net = sock_net(sk);
+        tn = net_generic(net, tipc_net_id);
+
         tsk = tipc_sk(sk);
         lock_sock(sk);