Bluetooth: Introduce user channel flag for HCI devices

This patch introduces a new user channel flag that allows to give full
control of a HCI device to a user application. The kernel will stay away
from the device and does not allow any further modifications of the
device states.

The existing raw flag is not used since it has a bit of unclear meaning
due to its legacy. Using a new flag makes the code clearer.

A device with the user channel flag set can still be enumerate using the
legacy API, but it does not longer enumerate using the new management
interface used by BlueZ 5 and beyond. This is intentional to not confuse
users of modern systems.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

1 files changed, 9 insertions, 6 deletions

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index ab570387f505..59e68f199178 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -500,6 +500,9 @@ static int hci_sock_bound_ioctl(struct sock *sk, unsigned int cmd,
 	if (!hdev)
 		return -EBADFD;
 
+	if (test_bit(HCI_USER_CHANNEL, &hdev->dev_flags))
+		return -EBUSY;
+
 	switch (cmd) {
 	case HCISETRAW:
 		if (!capable(CAP_NET_ADMIN))
@@ -530,19 +533,19 @@ static int hci_sock_bound_ioctl(struct sock *sk, unsigned int cmd,
 		if (!capable(CAP_NET_ADMIN))
 			return -EPERM;
 		return hci_sock_blacklist_del(hdev, (void __user *) arg);
-
-	default:
-		if (hdev->ioctl)
-			return hdev->ioctl(hdev, cmd, arg);
-		return -EINVAL;
 	}
+
+	if (hdev->ioctl)
+		return hdev->ioctl(hdev, cmd, arg);
+
+	return -EINVAL;
 }
 
 static int hci_sock_ioctl(struct socket *sock, unsigned int cmd,
 			  unsigned long arg)
 {
-	struct sock *sk = sock->sk;
 	void __user *argp = (void __user *) arg;
+	struct sock *sk = sock->sk;
 	int err;
 
 	BT_DBG("cmd %x arg %lx", cmd, arg);