/*
* Copyright (c) 2017 Nordic Semiconductor ASA
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <string.h>
#include <errno.h>
#include <zephyr.h>
#include <misc/byteorder.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/conn.h>
#include <tinycrypt/constants.h>
#include <tinycrypt/hmac_prng.h>
#include <tinycrypt/aes.h>
#include <tinycrypt/utils.h>
#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_CORE)
#define LOG_MODULE_NAME bt_crypto
#include "common/log.h"
#include "hci_core.h"
static struct tc_hmac_prng_struct prng;
static int prng_reseed(struct tc_hmac_prng_struct *h)
{
u8_t seed[32];
s64_t extra;
int ret, i;
for (i = 0; i < (sizeof(seed) / 8); i++) {
struct bt_hci_rp_le_rand *rp;
struct net_buf *rsp;
ret = bt_hci_cmd_send_sync(BT_HCI_OP_LE_RAND, NULL, &rsp);
if (ret) {
return ret;
}
rp = (void *)rsp->data;
memcpy(&seed[i * 8], rp->rand, 8);
net_buf_unref(rsp);
}
extra = k_uptime_get();
ret = tc_hmac_prng_reseed(h, seed, sizeof(seed), (u8_t *)&extra,
sizeof(extra));
if (ret == TC_CRYPTO_FAIL) {
BT_ERR("Failed to re-seed PRNG");
return -EIO;
}
return 0;
}
int prng_init(void)
{
struct bt_hci_rp_le_rand *rp;
struct net_buf *rsp;
int ret;
/* Check first that HCI_LE_Rand is supported */
if (!BT_CMD_TEST(bt_dev.supported_commands, 27, 7)) {
return -ENOTSUP;
}
ret = bt_hci_cmd_send_sync(BT_HCI_OP_LE_RAND, NULL, &rsp);
if (ret) {
return ret;
}
rp = (void *)rsp->data;
ret = tc_hmac_prng_init(&prng, rp->rand, sizeof(rp->rand));
net_buf_unref(rsp);
if (ret == TC_CRYPTO_FAIL) {
BT_ERR("Failed to initialize PRNG");
return -EIO;
}
/* re-seed is needed after init */
return prng_reseed(&prng);
}
int bt_rand(void *buf, size_t len)
{
int ret;
ret = tc_hmac_prng_generate(buf, len, &prng);
if (ret == TC_HMAC_PRNG_RESEED_REQ) {
ret = prng_reseed(&prng);
if (ret) {
return ret;
}
ret = tc_hmac_prng_generate(buf, len, &prng);
}
if (ret == TC_CRYPTO_SUCCESS) {
return 0;
}
return -EIO;
}
int bt_encrypt_le(const u8_t key[16], const u8_t plaintext[16],
u8_t enc_data[16])
{
struct tc_aes_key_sched_struct s;
u8_t tmp[16];
BT_DBG("key %s plaintext %s", bt_hex(key, 16), bt_hex(plaintext, 16));
sys_memcpy_swap(tmp, key, 16);
if (tc_aes128_set_encrypt_key(&s, tmp) == TC_CRYPTO_FAIL) {
return -EINVAL;
}
sys_memcpy_swap(tmp, plaintext, 16);
if (tc_aes_encrypt(enc_data, tmp, &s) == TC_CRYPTO_FAIL) {
return -EINVAL;
}
sys_mem_swap(enc_data, 16);
BT_DBG("enc_data %s", bt_hex(enc_data, 16));
return 0;
}
int bt_encrypt_be(const u8_t key[16], const u8_t plaintext[16],
u8_t enc_data[16])
{
struct tc_aes_key_sched_struct s;
BT_DBG("key %s plaintext %s", bt_hex(key, 16), bt_hex(plaintext, 16));
if (tc_aes128_set_encrypt_key(&s, key) == TC_CRYPTO_FAIL) {
return -EINVAL;
}
if (tc_aes_encrypt(enc_data, plaintext, &s) == TC_CRYPTO_FAIL) {
return -EINVAL;
}
BT_DBG("enc_data %s", bt_hex(enc_data, 16));
return 0;
}