Bluetooth: Add function to derive AMP key using hmac
hmac(sha256) will be used for AMP key generation.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c
index 8ef912c..ea4d5ff 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -16,6 +16,7 @@
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/a2mp.h>
#include <net/bluetooth/amp.h>
+#include <crypto/hash.h>
/* Remote AMP Controllers interface */
static void amp_ctrl_get(struct amp_ctrl *ctrl)
@@ -125,6 +126,41 @@
return hcon;
}
+/* AMP crypto key generation interface */
+static int hmac_sha256(u8 *key, u8 ksize, char *plaintext, u8 psize, u8 *output)
+{
+ int ret = 0;
+ struct crypto_shash *tfm;
+
+ if (!ksize)
+ return -EINVAL;
+
+ tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
+ if (IS_ERR(tfm)) {
+ BT_DBG("crypto_alloc_ahash failed: err %ld", PTR_ERR(tfm));
+ return PTR_ERR(tfm);
+ }
+
+ ret = crypto_shash_setkey(tfm, key, ksize);
+ if (ret) {
+ BT_DBG("crypto_ahash_setkey failed: err %d", ret);
+ } else {
+ struct {
+ struct shash_desc shash;
+ char ctx[crypto_shash_descsize(tfm)];
+ } desc;
+
+ desc.shash.tfm = tfm;
+ desc.shash.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ ret = crypto_shash_digest(&desc.shash, plaintext, psize,
+ output);
+ }
+
+ crypto_free_shash(tfm);
+ return ret;
+}
+
void amp_read_loc_assoc_frag(struct hci_dev *hdev, u8 phy_handle)
{
struct hci_cp_read_local_amp_assoc cp;