net/x25: Fix x25_neigh refcnt leak when x25 disconnect

x25_connect() invokes x25_get_neigh(), which returns a reference of the specified x25_neigh object to "x25->neighbour" with increased refcnt. When x25 connect success and returns, the reference still be hold by "x25->neighbour", so the refcount should be decreased in x25_disconnect() to keep refcount balanced. The reference counting issue happens in x25_disconnect(), which forgets to decrease the refcnt increased by x25_get_neigh() in x25_connect(), causing a refcnt leak. Fix this issue by calling x25_neigh_put() before x25_disconnect() returns. Signed-off-by: Xiyu Yang <[email protected]> Signed-off-by: Xin Tan <[email protected]> Signed-off-by: David S. Miller <[email protected]>
raspberrypi · Apr 27, 2020 · 4becb7e · 4becb7e
1 parent 095f561
commit 4becb7e
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
@@ -357,6 +357,10 @@ void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
 		sk->sk_state_change(sk);
 		sock_set_flag(sk, SOCK_DEAD);
 	}
+	read_lock_bh(&x25_list_lock);
+	x25_neigh_put(x25->neighbour);
+	x25->neighbour = NULL;
+	read_unlock_bh(&x25_list_lock);
 }
 
 /*