On Mon, Jun 14, 2021 at 04:15:02PM +0200, Eric Dumazet wrote:
>
>
> 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 ?
>
>
Odd, Lin, did you see any problems with your testing of this?
