linux/include/net/nfc
Lin Ma 48b71a9e66 NFC: add NCI_UNREG flag to eliminate the race
There are two sites that calls queue_work() after the
destroy_workqueue() and lead to possible UAF.

The first site is nci_send_cmd(), which can happen after the
nci_close_device as below

nfcmrvl_nci_unregister_dev   |  nfc_genl_dev_up
  nci_close_device           |
    flush_workqueue          |
    del_timer_sync           |
  nci_unregister_device      |    nfc_get_device
    destroy_workqueue        |    nfc_dev_up
    nfc_unregister_device    |      nci_dev_up
      device_del             |        nci_open_device
                             |          __nci_request
                             |            nci_send_cmd
                             |              queue_work !!!

Another site is nci_cmd_timer, awaked by the nci_cmd_work from the
nci_send_cmd.

  ...                        |  ...
  nci_unregister_device      |  queue_work
    destroy_workqueue        |
    nfc_unregister_device    |  ...
      device_del             |  nci_cmd_work
                             |  mod_timer
                             |  ...
                             |  nci_cmd_timer
                             |    queue_work !!!

For the above two UAF, the root cause is that the nfc_dev_up can race
between the nci_unregister_device routine. Therefore, this patch
introduce NCI_UNREG flag to easily eliminate the possible race. In
addition, the mutex_lock in nci_close_device can act as a barrier.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Fixes: 6a2968aaf5 ("NFC: basic NCI protocol implementation")
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211116152732.19238-1-linma@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-17 20:17:05 -08:00
..
digital.h nfc: constify nfc_digital_ops 2021-07-25 09:21:21 +01:00
hci.h nfc: constify nfc_hci_ops 2021-07-25 09:21:21 +01:00
llc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 399 2019-06-05 17:37:12 +02:00
nci_core.h NFC: add NCI_UNREG flag to eliminate the race 2021-11-17 20:17:05 -08:00
nci.h net/nfc/nci: Support NCI 2.x initial sequence 2020-12-04 17:47:35 -08:00
nfc.h nfc: constify several pointers to u8, char and sk_buff 2021-07-30 17:22:52 +02:00