linux/net/bluetooth/rfcomm
Peter Hurley b92483d54a Bluetooth: Fix unsafe RFCOMM device parenting
Accessing the results of hci_conn_hash_lookup_ba() is unsafe without
holding the hci_dev_lock() during the lookup. For example:

CPU 0                             | CPU 1
hci_conn_hash_lookup_ba           | hci_conn_del
  rcu_read_lock                   |   hci_conn_hash_del
  list_for_each_entry_rcu         |     list_del_rcu
    if (.....)                    |       synchronize_rcu
      rcu_read_unlock             |
                                  |   hci_conn_del_sysfs
                                  |   hci_dev_put
                                  |   hci_conn_put
                                  |     put_device (last reference)
                                  |       bt_link_release
                                  |         kfree(conn)
      return p  << just freed     |

Even if a hci_conn reference were taken (via hci_conn_get), would
not guarantee the lifetime of the sysfs device, but only safe
access to the in-memory structure.

Ensure the hci_conn device stays valid while the rfcomm device
is reparented; rename rfcomm_get_device() to rfcomm_reparent_device()
and perform the reparenting within the function while holding the
hci_dev_lock.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Tested-By: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2014-02-14 13:39:31 -08:00
..
core.c Bluetooth: Directly close dlc for not yet started RFCOMM session 2014-02-14 13:39:31 -08:00
Kconfig tty: Added a CONFIG_TTY option to allow removal of TTY 2013-01-18 16:15:27 -08:00
Makefile
sock.c Bluetooth: Refuse peer RFCOMM address reading when not connected 2014-02-13 09:51:39 +02:00
tty.c Bluetooth: Fix unsafe RFCOMM device parenting 2014-02-14 13:39:31 -08:00