net: diag: Fix refcnt leak in error path destroying socket

inet_diag_find_one_icsk takes a reference to a socket that is not
released if sock_diag_destroy returns an error. Fix by changing
tcp_diag_destroy to manage the refcnt for all cases and remove
the sock_put calls from tcp_abort.

Fixes: c1e64e298b8ca ("net: diag: Support destroying TCP sockets")
Reported-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 4d61093..a748c74 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -54,11 +54,16 @@
 {
 	struct net *net = sock_net(in_skb->sk);
 	struct sock *sk = inet_diag_find_one_icsk(net, &tcp_hashinfo, req);
+	int err;
 
 	if (IS_ERR(sk))
 		return PTR_ERR(sk);
 
-	return sock_diag_destroy(sk, ECONNABORTED);
+	err = sock_diag_destroy(sk, ECONNABORTED);
+
+	sock_gen_put(sk);
+
+	return err;
 }
 #endif