From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
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 <andrei.emeltchenko@xxxxxxxxx>
---
include/net/bluetooth/pal.h | 1 +
net/bluetooth/Kconfig | 1 +
net/bluetooth/pal.c | 45 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 47 insertions(+)
diff --git a/include/net/bluetooth/pal.h b/include/net/bluetooth/pal.h
index 6ce1dfb..8799285 100644
--- a/include/net/bluetooth/pal.h
+++ b/include/net/bluetooth/pal.h
@@ -53,5 +53,6 @@ int phylink_put(struct phy_link *plink);
void phylink_get(struct phy_link *plink);
void phylink_list_flush(struct amp_mgr *mgr);
void phylink_del(struct amp_mgr *mgr, struct phy_link *plink);
+int phylink_gen_key(struct hci_conn *conn, u8 *data, u8 *len, u8 *type);
#endif /* __PAL_H */
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/pal.c b/net/bluetooth/pal.c
index e766a98..b4eeb6a 100644
--- a/net/bluetooth/pal.c
+++ b/net/bluetooth/pal.c
@@ -255,3 +255,48 @@ int hmac_sha256(u8 *key, u8 ksize, char *plaintext, u8 psize, u8 *output)
crypto_free_shash(tfm);
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);
+}
--
1.7.9.5
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