From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
Function calculates AMP key using hmac_sha256 helper.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
---
include/net/bluetooth/pal.h | 1 +
net/bluetooth/pal.c | 61 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 62 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/pal.c b/net/bluetooth/pal.c
index e9bab6c..dbca318 100644
--- a/net/bluetooth/pal.c
+++ b/net/bluetooth/pal.c
@@ -255,3 +255,64 @@ int hmac_sha256(u8 *key, u8 ksize, char *plaintext, u8 psize, u8 *output)
crypto_free_shash(tfm);
return ret;
}
+
+static void hexdump(u8 *buf, size_t len)
+{
+ print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,
+ 16, 1, buf, len, false);
+}
+
+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];
+ u8 b802_key[HCI_AMP_LINK_KEY_SIZE];
+ int result;
+
+ if (!hci_conn_check_link_mode(conn))
+ return -EACCES;
+
+ BT_DBG("key_type %d", conn->key_type);
+
+ /* Legacy key */
+ if (conn->key_type < 3)
+ return -EACCES;
+
+ *type = conn->key_type;
+ *len = HCI_AMP_LINK_KEY_SIZE;
+
+ hci_dev_lock(hdev);
+ key = hci_find_link_key(hdev, &conn->dst);
+ hci_dev_unlock(hdev);
+
+ /* 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);
+
+ hexdump(keybuf, HCI_AMP_LINK_KEY_SIZE);
+
+ result = hmac_sha256(keybuf, HCI_AMP_LINK_KEY_SIZE, "gamp", 4,
+ gamp_key);
+ hexdump(gamp_key, HCI_AMP_LINK_KEY_SIZE);
+
+ if (result)
+ goto done;
+
+ if (conn->key_type == 3) {
+ BT_DBG("gamp_key");
+ hexdump(gamp_key, HCI_AMP_LINK_KEY_SIZE);
+ memcpy(data, gamp_key, HCI_AMP_LINK_KEY_SIZE);
+ goto done;
+ }
+
+ result = hmac_sha256(gamp_key, HCI_AMP_LINK_KEY_SIZE, "802b", 4,
+ b802_key);
+ hexdump(b802_key, HCI_AMP_LINK_KEY_SIZE);
+
+ memcpy(data, b802_key, HCI_AMP_LINK_KEY_SIZE);
+
+done:
+ return result;
+}
--
1.7.9.5
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