amt: do not use amt->nr_tunnels outside of lock

amt->nr_tunnels is protected by amt->lock.
But, amt_request_handler() has been using this variable without the
amt->lock.
So, it expands context of amt->lock in the amt_request_handler() to
protect amt->nr_tunnels variable.

Fixes: cbc21dc1cfe9 ("amt: add data plane of amt interface")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index 051e92e..e019526 100644 (file)
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c
@@ -2679,7 +2679,9 @@ static bool amt_request_handler(struct amt_dev *amt, struct sk_buff *skb)
                if (tunnel->ip4 == iph->saddr)
                        goto send;
 
+       spin_lock_bh(&amt->lock);
        if (amt->nr_tunnels >= amt->max_tunnels) {
+               spin_unlock_bh(&amt->lock);
                icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
                return true;
        }
@@ -2687,8 +2689,10 @@ static bool amt_request_handler(struct amt_dev *amt, struct sk_buff *skb)
        tunnel = kzalloc(sizeof(*tunnel) +
                         (sizeof(struct hlist_head) * amt->hash_buckets),
                         GFP_ATOMIC);
-       if (!tunnel)
+       if (!tunnel) {
+               spin_unlock_bh(&amt->lock);
                return true;
+       }
 
        tunnel->source_port = udph->source;
        tunnel->ip4 = iph->saddr;
@@ -2701,10 +2705,9 @@ static bool amt_request_handler(struct amt_dev *amt, struct sk_buff *skb)
 
        INIT_DELAYED_WORK(&tunnel->gc_wq, amt_tunnel_expire);
 
-       spin_lock_bh(&amt->lock);
        list_add_tail_rcu(&tunnel->list, &amt->tunnel_list);
        tunnel->key = amt->key;
-       amt_update_relay_status(tunnel, AMT_STATUS_RECEIVED_REQUEST, true);
+       __amt_update_relay_status(tunnel, AMT_STATUS_RECEIVED_REQUEST, true);
        amt->nr_tunnels++;
        mod_delayed_work(amt_wq, &tunnel->gc_wq,
                         msecs_to_jiffies(amt_gmi(amt)));