From 5a349186692950b13896abc3fb2f491d023f95a1 Mon Sep 17 00:00:00 2001 From: Andrei Emeltchenko Date: Thu, 27 Sep 2012 17:26:18 +0300 Subject: [PATCH] Bluetooth: AMP: Add AMP key calculation Function calculates AMP keys using hmac_sha256 helper. Calculated keys are Generic AMP Link Key (gamp) and Dedicated AMP Link Key with keyID "802b" for 802.11 PAL. Signed-off-by: Andrei Emeltchenko Signed-off-by: Gustavo Padovan --- include/net/bluetooth/amp.h | 2 ++ net/bluetooth/Kconfig | 1 + net/bluetooth/amp.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 48 insertions(+) diff --git a/include/net/bluetooth/amp.h b/include/net/bluetooth/amp.h index f57854f..763b463 100644 --- a/include/net/bluetooth/amp.h +++ b/include/net/bluetooth/amp.h @@ -32,6 +32,8 @@ void amp_ctrl_list_flush(struct amp_mgr *mgr); struct hci_conn *phylink_add(struct hci_dev *hdev, struct amp_mgr *mgr, u8 remote_id); +int phylink_gen_key(struct hci_conn *hcon, u8 *data, u8 *len, u8 *type); + void amp_read_loc_info(struct hci_dev *hdev, struct amp_mgr *mgr); void amp_read_loc_assoc_frag(struct hci_dev *hdev, u8 phy_handle); void amp_read_loc_assoc(struct hci_dev *hdev, struct amp_mgr *mgr); diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig index 3537d38..1c11d0d 100644 --- a/net/bluetooth/Kconfig +++ b/net/bluetooth/Kconfig @@ -11,6 +11,7 @@ menuconfig BT select CRYPTO_BLKCIPHER select CRYPTO_AES select CRYPTO_ECB + select CRYPTO_SHA256 help Bluetooth is low-cost, low-power, short-range wireless technology. It was designed as a replacement for cables and other short-range diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c index ea4d5ff..67bc2c2f 100644 --- a/net/bluetooth/amp.c +++ b/net/bluetooth/amp.c @@ -161,6 +161,51 @@ static int hmac_sha256(u8 *key, u8 ksize, char *plaintext, u8 psize, u8 *output) return ret; } +int phylink_gen_key(struct hci_conn *conn, u8 *data, u8 *len, u8 *type) +{ + struct hci_dev *hdev = conn->hdev; + struct link_key *key; + u8 keybuf[HCI_AMP_LINK_KEY_SIZE]; + u8 gamp_key[HCI_AMP_LINK_KEY_SIZE]; + int err; + + if (!hci_conn_check_link_mode(conn)) + return -EACCES; + + BT_DBG("conn %p key_type %d", conn, conn->key_type); + + /* Legacy key */ + if (conn->key_type < 3) { + BT_ERR("Legacy key type %d", conn->key_type); + return -EACCES; + } + + *type = conn->key_type; + *len = HCI_AMP_LINK_KEY_SIZE; + + key = hci_find_link_key(hdev, &conn->dst); + + /* BR/EDR Link Key concatenated together with itself */ + memcpy(&keybuf[0], key->val, HCI_LINK_KEY_SIZE); + memcpy(&keybuf[HCI_LINK_KEY_SIZE], key->val, HCI_LINK_KEY_SIZE); + + /* Derive Generic AMP Link Key (gamp) */ + err = hmac_sha256(keybuf, HCI_AMP_LINK_KEY_SIZE, "gamp", 4, gamp_key); + if (err) { + BT_ERR("Could not derive Generic AMP Key: err %d", err); + return err; + } + + if (conn->key_type == HCI_LK_DEBUG_COMBINATION) { + BT_DBG("Use Generic AMP Key (gamp)"); + memcpy(data, gamp_key, HCI_AMP_LINK_KEY_SIZE); + return err; + } + + /* Derive Dedicated AMP Link Key: "802b" is 802.11 PAL keyID */ + return hmac_sha256(gamp_key, HCI_AMP_LINK_KEY_SIZE, "802b", 4, data); +} + void amp_read_loc_assoc_frag(struct hci_dev *hdev, u8 phy_handle) { struct hci_cp_read_local_amp_assoc cp; -- 2.7.4