Bluetooth: hci_sock: purge socket queues in the destruct() callback

The receive path may take the socket right before hci_sock_release(),
but it may enqueue the packets to the socket queues after the call to
skb_queue_purge(), therefore the socket can be destroyed without clear
its queues completely.

Moving these skb_queue_purge() to the hci_sock_destruct() will fix this
issue, because nothing is referencing the socket at this point.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index d0dad1f..446573a 100644 (file)
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -889,10 +889,6 @@ static int hci_sock_release(struct socket *sock)
        }
 
        sock_orphan(sk);
-
-       skb_queue_purge(&sk->sk_receive_queue);
-       skb_queue_purge(&sk->sk_write_queue);
-
        release_sock(sk);
        sock_put(sk);
        return 0;
@@ -2058,6 +2054,12 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname,
        return err;
 }
 
+static void hci_sock_destruct(struct sock *sk)
+{
+       skb_queue_purge(&sk->sk_receive_queue);
+       skb_queue_purge(&sk->sk_write_queue);
+}
+
 static const struct proto_ops hci_sock_ops = {
        .family         = PF_BLUETOOTH,
        .owner          = THIS_MODULE,
@@ -2111,6 +2113,7 @@ static int hci_sock_create(struct net *net, struct socket *sock, int protocol,
 
        sock->state = SS_UNCONNECTED;
        sk->sk_state = BT_OPEN;
+       sk->sk_destruct = hci_sock_destruct;
 
        bt_sock_link(&hci_sk_list, sk);
        return 0;