On 6/8/21 8:27 PM, Greg Kroah-Hartman wrote:
> From: Lin Ma <linma@xxxxxxxxxx>
>
> commit e305509e678b3a4af2b3cfd410f409f7cdaabb52 upstream.
>
> The hci_sock_dev_event() function will cleanup the hdev object for
> sockets even if this object may still be in used within the
> hci_sock_bound_ioctl() function, result in UAF vulnerability.
>
> This patch replace the BH context lock to serialize these affairs
> and prevent the race condition.
>
> Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
> Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> net/bluetooth/hci_sock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -755,7 +755,7 @@ void hci_sock_dev_event(struct hci_dev *
> /* Detach sockets from device */
> read_lock(&hci_sk_list.lock);
> sk_for_each(sk, &hci_sk_list.head) {
> - bh_lock_sock_nested(sk);
> + lock_sock(sk);
> if (hci_pi(sk)->hdev == hdev) {
> hci_pi(sk)->hdev = NULL;
> sk->sk_err = EPIPE;
> @@ -764,7 +764,7 @@ void hci_sock_dev_event(struct hci_dev *
>
> hci_dev_put(hdev);
> }
> - bh_unlock_sock(sk);
> + release_sock(sk);
> }
> read_unlock(&hci_sk_list.lock);
> }
>
>
This patch is buggy.
lock_sock() can sleep.
But the read_lock(&hci_sk_list.lock) two lines before is not going to allow the sleep.
Hmmm ?
