queue-5.0/bluetooth-align-minimum-encryption-key-size-for-le-and-br-edr-connections.patch

   1 From d5bb334a8e171b262e48f378bd2096c0ea458265 Mon Sep 17 00:00:00 2001
   2 From: Marcel Holtmann <marcel@holtmann.org>
   3 Date: Wed, 24 Apr 2019 22:19:17 +0200
   4 Subject: Bluetooth: Align minimum encryption key size for LE and BR/EDR connections
   5
   6 From: Marcel Holtmann <marcel@holtmann.org>
   7
   8 commit d5bb334a8e171b262e48f378bd2096c0ea458265 upstream.
   9
  10 The minimum encryption key size for LE connections is 56 bits and to
  11 align LE with BR/EDR, enforce 56 bits of minimum encryption key size for
  12 BR/EDR connections as well.
  13
  14 Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
  15 Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
  16 Cc: stable@vger.kernel.org
  17 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  18
  19 ---
  20  include/net/bluetooth/hci_core.h |    3 +++
  21  net/bluetooth/hci_conn.c         |    8 ++++++++
  22  2 files changed, 11 insertions(+)
  23
  24 --- a/include/net/bluetooth/hci_core.h
  25 +++ b/include/net/bluetooth/hci_core.h
  26 @@ -190,6 +190,9 @@ struct adv_info {
  27
  28  #define HCI_MAX_SHORT_NAME_LENGTH      10
  29
  30 +/* Min encryption key size to match with SMP */
  31 +#define HCI_MIN_ENC_KEY_SIZE           7
  32 +
  33  /* Default LE RPA expiry time, 15 minutes */
  34  #define HCI_DEFAULT_RPA_TIMEOUT                (15 * 60)
  35
  36 --- a/net/bluetooth/hci_conn.c
  37 +++ b/net/bluetooth/hci_conn.c
  38 @@ -1276,6 +1276,14 @@ int hci_conn_check_link_mode(struct hci_
  39             !test_bit(HCI_CONN_ENCRYPT, &conn->flags))
  40                 return 0;
  41
  42 +       /* The minimum encryption key size needs to be enforced by the
  43 +        * host stack before establishing any L2CAP connections. The
  44 +        * specification in theory allows a minimum of 1, but to align
  45 +        * BR/EDR and LE transports, a minimum of 7 is chosen.
  46 +        */
  47 +       if (conn->enc_key_size < HCI_MIN_ENC_KEY_SIZE)
  48 +               return 0;
  49 +
  50         return 1;
  51  }
  52