libosdp-sys 3.2.1

Sys crate for https://github.com/goToMain/libosdp
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96

/*
 * Copyright (c) 2021-2026 Siddharth Chandrasekaran <sidcha.dev@gmail.com>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdint.h>
#include <string.h>
#include <assert.h>

#include <mbedtls/aes.h>
#include <mbedtls/entropy.h>
#include <mbedtls/ctr_drbg.h>

#include <osdp.h>

mbedtls_aes_context aes_ctx;
mbedtls_entropy_context entropy_ctx;
mbedtls_ctr_drbg_context ctr_drbg_ctx;

void osdp_crypt_setup()
{
	int rc;
	const char *version;

	version = osdp_get_version();
	mbedtls_aes_init(&aes_ctx);
	mbedtls_entropy_init(&entropy_ctx);
	mbedtls_ctr_drbg_init(&ctr_drbg_ctx);

	rc = mbedtls_ctr_drbg_seed(&ctr_drbg_ctx,
				   mbedtls_entropy_func,
				   &entropy_ctx,
				   (const unsigned char *)version,
				   strlen(version));
	assert(rc == 0);
}

void osdp_encrypt(uint8_t *key, uint8_t *iv, uint8_t *data, int len)
{
	int rc;

	if (iv != NULL) {
		/* encrypt multiple block with AES in CBC mode */
		rc = mbedtls_aes_setkey_enc(&aes_ctx, key, 128);
		assert(rc == 0);
		rc = mbedtls_aes_crypt_cbc(&aes_ctx, MBEDTLS_AES_ENCRYPT,
					   len, iv, data, data);
		assert(rc == 0);
	} else {
		/* encrypt one block with AES in ECB mode */
		assert(len <= 16);
		rc = mbedtls_aes_setkey_enc(&aes_ctx, key, 128);
		assert(rc == 0);
		rc = mbedtls_aes_crypt_ecb(&aes_ctx, MBEDTLS_AES_ENCRYPT,
					   data, data);
		assert(rc == 0);
	}
}

void osdp_decrypt(uint8_t *key, uint8_t *iv, uint8_t *data, int len)
{
	int rc;

	if (iv != NULL) {
		/* decrypt multiple block with AES in CBC mode */
		rc = mbedtls_aes_setkey_dec(&aes_ctx, key, 128);
		assert(rc == 0);
		rc = mbedtls_aes_crypt_cbc(&aes_ctx, MBEDTLS_AES_DECRYPT,
					   len, iv, data, data);
		assert(rc == 0);
	} else {
		/* decrypt one block with AES in ECB mode */
		assert(len <= 16);
		rc = mbedtls_aes_setkey_dec(&aes_ctx, key, 128);
		assert(rc == 0);
		rc = mbedtls_aes_crypt_ecb(&aes_ctx, MBEDTLS_AES_DECRYPT,
					   data, data);
		assert(rc == 0);
	}
}

void osdp_fill_random(uint8_t *buf, int len)
{
	int rc;

	rc = mbedtls_ctr_drbg_random(&ctr_drbg_ctx, buf, len);
	assert(rc == 0);
}

void osdp_crypt_teardown()
{
	mbedtls_ctr_drbg_free(&ctr_drbg_ctx);
	mbedtls_entropy_free(&entropy_ctx);
	mbedtls_aes_free(&aes_ctx);
}