Bluetooth: purge error queues in socket destructors

When TX timestamping is enabled via SO_TIMESTAMPING, SKBs may be queued
into sk_error_queue and will stay there until consumed. If userspace never
gets to read the timestamps, or if the controller is removed unexpectedly,
these SKBs will leak.

Fix by adding skb_queue_purge() calls for sk_error_queue in affected
bluetooth destructors. RFCOMM does not currently use sk_error_queue.

Fixes: 134f4b3 ("Bluetooth: add support for skb TX SND/COMPLETION timestamping")
Reported-by: syzbot+7ff4013eabad1407b70a@syzkaller.appspotmail.com
Closes: https://syzbot.org/bug?extid=7ff4013eabad1407b70a
Cc: stable@vger.kernel.org
Signed-off-by: Heitor Alves de Siqueira <halves@igalia.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Author: hrasiq

net/bluetooth/hci_sock.c

@@ -2166,6 +2166,7 @@ static void hci_sock_destruct(struct sock *sk)
 	mgmt_cleanup(sk);
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
+	skb_queue_purge(&sk->sk_error_queue);
 }
 
 static const struct proto_ops hci_sock_ops = {

net/bluetooth/iso.c

@@ -746,6 +746,7 @@ static void iso_sock_destruct(struct sock *sk)
 
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
+	skb_queue_purge(&sk->sk_error_queue);
 }
 
 static void iso_sock_cleanup_listen(struct sock *parent)

net/bluetooth/l2cap_sock.c

@@ -1817,6 +1817,7 @@ static void l2cap_sock_destruct(struct sock *sk)
 
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
+	skb_queue_purge(&sk->sk_error_queue);
 }
 
 static void l2cap_skb_msg_name(struct sk_buff *skb, void *msg_name,

net/bluetooth/sco.c

@@ -470,6 +470,7 @@ static void sco_sock_destruct(struct sock *sk)
 
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
+	skb_queue_purge(&sk->sk_error_queue);
 }
 
 static void sco_sock_cleanup_listen(struct sock *parent)