Hi Andrei,
* Andrei Emeltchenko <Andrei.Emeltchenko.news@xxxxxxxxx> [2012-07-24 16:21:55 +0300]:
> 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/Kconfig | 1 +
> net/bluetooth/pal.c | 61 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 63 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 a405e88..c47eeac 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);
Is these hex prints worthwhile? Seems kind expensive, right?
> +
> + 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);
Can't you pass data directly here, instead of b802_key? This could avoid an
extra memcpy.
Gustavo
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