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>

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index c9c34a6679213e61c19cb6f691d7173776315369..720fda6cc2e6223771f3df5b21885cb10d5c7b2d 100644 (file)
--- 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);