128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
/**
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* @file rpa.c
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* Resolvable Private Address Generation and Resolution
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*/
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/*
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* Copyright (c) 2017 Nordic Semiconductor ASA
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* Copyright (c) 2015-2016 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/kernel.h>
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#include <stddef.h>
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#include <errno.h>
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#include <string.h>
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#include "common/bt_str.h"
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#include <zephyr/bluetooth/crypto.h>
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#define LOG_LEVEL CONFIG_BT_RPA_LOG_LEVEL
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#include <zephyr/logging/log.h>
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LOG_MODULE_REGISTER(bt_rpa);
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#if defined(CONFIG_BT_CTLR) && defined(CONFIG_BT_HOST_CRYPTO)
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#include "../controller/util/util.h"
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#include "../controller/hal/ecb.h"
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#endif /* defined(CONFIG_BT_CTLR) && defined(CONFIG_BT_HOST_CRYPTO) */
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#if defined(CONFIG_BT_PRIVACY) || defined(CONFIG_BT_CTLR_PRIVACY)
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static int internal_rand(void *buf, size_t len)
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{
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/* Force using controller rand function. */
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#if defined(CONFIG_BT_CTLR) && defined(CONFIG_BT_HOST_CRYPTO)
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return lll_csrand_get(buf, len);
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#else
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return bt_rand(buf, len);
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#endif
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}
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#endif /* defined(CONFIG_BT_PRIVACY) || defined(CONFIG_BT_CTLR_PRIVACY) */
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static int internal_encrypt_le(const uint8_t key[16], const uint8_t plaintext[16],
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uint8_t enc_data[16])
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{
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/* Force using controller encrypt function if supported. */
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#if defined(CONFIG_BT_CTLR) && defined(CONFIG_BT_HOST_CRYPTO) && \
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defined(CONFIG_BT_CTLR_LE_ENC)
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ecb_encrypt(key, plaintext, enc_data, NULL);
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return 0;
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#else
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return bt_encrypt_le(key, plaintext, enc_data);
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#endif
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}
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static int ah(const uint8_t irk[16], const uint8_t r[3], uint8_t out[3])
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{
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uint8_t res[16];
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int err;
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LOG_DBG("irk %s", bt_hex(irk, 16));
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LOG_DBG("r %s", bt_hex(r, 3));
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/* r' = padding || r */
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memcpy(res, r, 3);
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(void)memset(res + 3, 0, 13);
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err = internal_encrypt_le(irk, res, res);
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if (err) {
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return err;
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}
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/* The output of the random address function ah is:
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* ah(h, r) = e(k, r') mod 2^24
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* The output of the security function e is then truncated to 24 bits
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* by taking the least significant 24 bits of the output of e as the
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* result of ah.
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*/
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memcpy(out, res, 3);
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return 0;
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}
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#if defined(CONFIG_BT_SMP) || defined(CONFIG_BT_CTLR_PRIVACY)
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bool bt_rpa_irk_matches(const uint8_t irk[16], const bt_addr_t *addr)
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{
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uint8_t hash[3];
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int err;
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LOG_DBG("IRK %s bdaddr %s", bt_hex(irk, 16), bt_addr_str(addr));
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err = ah(irk, addr->val + 3, hash);
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if (err) {
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return false;
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}
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return !memcmp(addr->val, hash, 3);
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}
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#endif
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#if defined(CONFIG_BT_PRIVACY) || defined(CONFIG_BT_CTLR_PRIVACY)
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int bt_rpa_create(const uint8_t irk[16], bt_addr_t *rpa)
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{
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int err;
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err = internal_rand(rpa->val + 3, 3);
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if (err) {
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return err;
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}
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BT_ADDR_SET_RPA(rpa);
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err = ah(irk, rpa->val + 3, rpa->val);
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if (err) {
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return err;
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}
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LOG_DBG("Created RPA %s", bt_addr_str((bt_addr_t *)rpa->val));
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return 0;
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}
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#else
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int bt_rpa_create(const uint8_t irk[16], bt_addr_t *rpa)
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{
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return -ENOTSUP;
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}
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#endif /* CONFIG_BT_PRIVACY */
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