From d5bb334a8e171b262e48f378bd2096c0ea458265 Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Wed, 24 Apr 2019 22:19:17 +0200 Subject: [PATCH] Bluetooth: Align minimum encryption key size for LE and BR/EDR connections The minimum encryption key size for LE connections is 56 bits and to align LE with BR/EDR, enforce 56 bits of minimum encryption key size for BR/EDR connections as well. Signed-off-by: Marcel Holtmann Signed-off-by: Johan Hedberg Cc: stable@vger.kernel.org --- include/net/bluetooth/hci_core.h | 3 +++ net/bluetooth/hci_conn.c | 8 ++++++++ 2 files changed, 11 insertions(+) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 094e61e07030..05b1b96f4d9e 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -190,6 +190,9 @@ struct adv_info { #define HCI_MAX_SHORT_NAME_LENGTH 10 +/* Min encryption key size to match with SMP */ +#define HCI_MIN_ENC_KEY_SIZE 7 + /* Default LE RPA expiry time, 15 minutes */ #define HCI_DEFAULT_RPA_TIMEOUT (15 * 60) diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index bd4978ce8c45..3cf0764d5793 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1276,6 +1276,14 @@ int hci_conn_check_link_mode(struct hci_conn *conn) !test_bit(HCI_CONN_ENCRYPT, &conn->flags)) return 0; + /* The minimum encryption key size needs to be enforced by the + * host stack before establishing any L2CAP connections. The + * specification in theory allows a minimum of 1, but to align + * BR/EDR and LE transports, a minimum of 7 is chosen. + */ + if (conn->enc_key_size < HCI_MIN_ENC_KEY_SIZE) + return 0; + return 1; }