Commit c7c999cb authored by Takashi Iwai's avatar Takashi Iwai Committed by Marcel Holtmann
Browse files

Bluetooth: vhci: Fix race at creating hci device 



hci_vhci driver creates a hci device object dynamically upon each
HCI_VENDOR_PKT write.  Although it checks the already created object
and returns an error, it's still racy and may build multiple hci_dev
objects concurrently when parallel writes are performed, as the device
tracks only a single hci_dev object.

This patch introduces a mutex to protect against the concurrent device
creations.

Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 60f5f5d3

drivers/bluetooth/hci_vhci.c

+17 −6
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct vhci_data { 
	wait_queue_head_t read_wait;

	struct sk_buff_head readq;



	struct mutex open_mutex;

	struct delayed_work open_timeout;

};
@@ -87,12 +88,15 @@ static int vhci_send_frame(struct hci_dev *hdev, struct sk_buff *skb) 
	return 0;

}



static int vhci_create_device(struct vhci_data *data, __u8 opcode)

static int __vhci_create_device(struct vhci_data *data, __u8 opcode)

{

	struct hci_dev *hdev;

	struct sk_buff *skb;

	__u8 dev_type;



	if (data->hdev)

		return -EBADFD;



	/* bits 0-1 are dev_type (BR/EDR or AMP) */

	dev_type = opcode & 0x03;
@@ -151,6 +155,17 @@ static int vhci_create_device(struct vhci_data *data, __u8 opcode) 
	return 0;

}



static int vhci_create_device(struct vhci_data *data, __u8 opcode)

{

	int err;



	mutex_lock(&data->open_mutex);

	err = __vhci_create_device(data, opcode);

	mutex_unlock(&data->open_mutex);



	return err;

}



static inline ssize_t vhci_get_user(struct vhci_data *data,

				    struct iov_iter *from)

{
@@ -191,11 +206,6 @@ static inline ssize_t vhci_get_user(struct vhci_data *data, 
	case HCI_VENDOR_PKT:

		cancel_delayed_work_sync(&data->open_timeout);



		if (data->hdev) {

			kfree_skb(skb);

			return -EBADFD;

		}



		opcode = *((__u8 *) skb->data);

		skb_pull(skb, 1);
@@ -320,6 +330,7 @@ static int vhci_open(struct inode *inode, struct file *file) 
	skb_queue_head_init(&data->readq);

	init_waitqueue_head(&data->read_wait);



	mutex_init(&data->open_mutex);

	INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout);



	file->private_data = data;

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