1 /*
2 * Copyright (c) 2022 HiSilicon (Shanghai) Technologies CO., LIMITED.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 /**
17 * This file make use the hmac to make mqtt pwd.
18 * The method is use the date string to hash the device passwd
19 * Take care that this implement depends on the hmac of the mbedtls
20 */
21 #include <stdint.h>
22 #include <stddef.h>
23 #include <string.h>
24 #include <stdio.h>
25 #include "md.h"
26 #include "md_internal.h"
27
28 #define CN_HMAC256_LEN_MAX (65)
29 #define CN_HMAC256_LEN 32
30 #define RIGHT_MOVE_BIT_4 (4)
31 #define NUMBER_9 (9)
32 #define DECIMAL_BASE (10)
33 #define STRING_LEN_TIMES (2)
34 #define LEN_TIMES (2)
35 #define OFFSET (1)
36 // make a byte to 2 ascii hex
byte2hexstr(unsigned char *bufin, int len, char *bufout)37 static int byte2hexstr(unsigned char *bufin, int len, char *bufout)
38 {
39 int i = 0;
40 unsigned char tmp_l = 0x0;
41 unsigned char tmp_h = 0;
42 if ((bufin == NULL)||(len <= 0)||(bufout == NULL)) {
43 return -1;
44 }
45 for (i = 0; i < len; i++) {
46 tmp_h = (bufin[i] >> RIGHT_MOVE_BIT_4) & 0X0F;
47 tmp_l = bufin[i] & 0x0F;
48 bufout[STRING_LEN_TIMES * i] = (tmp_h > NUMBER_9) ?
49 (tmp_h - DECIMAL_BASE + 'a'):(tmp_h +'0');
50 bufout[STRING_LEN_TIMES * i + OFFSET] = (tmp_l > NUMBER_9) ?
51 (tmp_l - DECIMAL_BASE + 'a'):(tmp_l +'0');
52 }
53 bufout[STRING_LEN_TIMES * len] = '\0';
54
55 return 0;
56 }
57
HmacGeneratePwd(const unsigned char *content, int contentLen, const unsigned char *key, int keyLen, unsigned char *buf)58 int HmacGeneratePwd(const unsigned char *content, int contentLen, const unsigned char *key,
59 int keyLen, unsigned char *buf)
60 {
61 int ret = -1;
62 mbedtls_md_context_t mbedtls_md_ctx;
63 const mbedtls_md_info_t *md_info;
64 unsigned char hash[CN_HMAC256_LEN];
65
66 if ((key == NULL)||(content == NULL)||(buf == NULL)||
67 (keyLen == 0)||(contentLen == 0)||
68 (CN_HMAC256_LEN_MAX < (CN_HMAC256_LEN * LEN_TIMES + OFFSET))) {
69 return ret;
70 }
71
72 md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
73 if ((md_info == NULL)||((size_t)md_info->size > CN_HMAC256_LEN)) {
74 return ret;
75 }
76
77 mbedtls_md_init(&mbedtls_md_ctx);
78 ret = mbedtls_md_setup(&mbedtls_md_ctx, md_info, 1);
79 if (ret != 0) {
80 mbedtls_md_free(&mbedtls_md_ctx);
81 return ret;
82 }
83
84 (void)mbedtls_md_hmac_starts(&mbedtls_md_ctx, key, keyLen);
85 (void)mbedtls_md_hmac_update(&mbedtls_md_ctx, content, contentLen);
86 (void)mbedtls_md_hmac_finish(&mbedtls_md_ctx, hash);
87
88 // <transfer the hash code to the string mode
89 ret = byte2hexstr(hash, CN_HMAC256_LEN, (char *)buf);
90 if (ret != 0) {
91 return ret;
92 }
93
94 return ret;
95 }