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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: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Takashi Iwai 2016-04-14 17:32:19 +02:00 committed by Marcel Holtmann
parent 60f5f5d3a1
commit c7c999cb18
1 changed files with 17 additions and 6 deletions
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23
drivers/bluetooth/hci_vhci.c
View File

@ -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;