1 /*
2 * Copyright (c) 2024 Nordic Semiconductor ASA
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/random/random.h>
8 #include <mbedtls/entropy.h>
9 #include <psa/crypto.h>
10
11
12 #if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR) || defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
get_random_data(uint8_t * output,size_t output_size,bool allow_non_cs)13 static int get_random_data(uint8_t *output, size_t output_size, bool allow_non_cs)
14 {
15 int ret = MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED;
16
17 #if defined(CONFIG_CSPRNG_ENABLED)
18 ret = sys_csrand_get(output, output_size);
19 if (ret == 0) {
20 return 0;
21 }
22 #endif /* CONFIG_CSPRNG_ENABLED */
23
24 if (allow_non_cs) {
25 sys_rand_get(output, output_size);
26 ret = 0;
27 }
28
29 return ret;
30 }
31 #endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR || CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
32
33 #if defined(CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR)
mbedtls_hardware_poll(void * data,unsigned char * output,size_t len,size_t * olen)34 int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len,
35 size_t *olen)
36 {
37 int ret;
38 uint16_t request_len = len > UINT16_MAX ? UINT16_MAX : len;
39
40 ARG_UNUSED(data);
41
42 if (output == NULL || olen == NULL || len == 0) {
43 return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
44 }
45
46 ret = get_random_data(output, len, true);
47 if (ret < 0) {
48 return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
49 }
50
51 *olen = request_len;
52
53 return 0;
54 }
55 #endif /* CONFIG_MBEDTLS_ENTROPY_POLL_ZEPHYR */
56
57 #if defined(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
mbedtls_psa_external_get_random(mbedtls_psa_external_random_context_t * context,uint8_t * output,size_t output_size,size_t * output_length)58 psa_status_t mbedtls_psa_external_get_random(
59 mbedtls_psa_external_random_context_t *context,
60 uint8_t *output, size_t output_size, size_t *output_length)
61 {
62 (void) context;
63 int ret;
64
65 ret = get_random_data(output, output_size,
66 IS_ENABLED(CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG));
67 if (ret != 0) {
68 return PSA_ERROR_GENERIC_ERROR;
69 }
70
71 *output_length = output_size;
72
73 return PSA_SUCCESS;
74 }
75 #endif /* CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
76
