1 /* $NetBSD: hmac.c,v 1.5 2017/10/05 09:59:04 roy Exp $ */
2
3 /*-
4 * Copyright (c) 2016 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <string.h>
33 #include <stdlib.h>
34
35 #include "config.h"
36
37 #if defined(HAVE_MD5_H) && !defined(DEPGEN)
38 #include <md5.h>
39 #endif
40
41 #ifdef SHA2_H
42 # include SHA2_H
43 #endif
44
45 #ifndef __arraycount
46 #define __arraycount(__x) (sizeof(__x) / sizeof(__x[0]))
47 #endif
48
49 #if 0
50 #include <md2.h>
51 #include <md4.h>
52 #include <md5.h>
53 #include <rmd160.h>
54 #include <sha1.h>
55 #include <sha2.h>
56 #endif
57
58 #ifndef MD5_BLOCK_LENGTH
59 #define MD5_BLOCK_LENGTH 64
60 #endif
61 #ifndef SHA256_BLOCK_LENGTH
62 #define SHA256_BLOCK_LENGTH 64
63 #endif
64
65 #define HMAC_SIZE 128
66 #define HMAC_IPAD 0x36
67 #define HMAC_OPAD 0x5C
68
69 static const struct hmac {
70 const char *name;
71 size_t ctxsize;
72 size_t digsize;
73 size_t blocksize;
74 void (*init)(void *);
75 void (*update)(void *, const uint8_t *, unsigned int);
76 void (*final)(uint8_t *, void *);
77 } hmacs[] = {
78 #if 0
79 {
80 "md2", sizeof(MD2_CTX), MD2_DIGEST_LENGTH, MD2_BLOCK_LENGTH,
81 (void *)MD2Init, (void *)MD2Update, (void *)MD2Final,
82 },
83 {
84 "md4", sizeof(MD4_CTX), MD4_DIGEST_LENGTH, MD4_BLOCK_LENGTH,
85 (void *)MD4Init, (void *)MD4Update, (void *)MD4Final,
86 },
87 #endif
88 {
89 "md5", sizeof(MD5_CTX), MD5_DIGEST_LENGTH, MD5_BLOCK_LENGTH,
90 (void *)MD5Init, (void *)MD5Update, (void *)MD5Final,
91 },
92 #if 0
93 {
94 "rmd160", sizeof(RMD160_CTX), RMD160_DIGEST_LENGTH,
95 RMD160_BLOCK_LENGTH,
96 (void *)RMD160Init, (void *)RMD160Update, (void *)RMD160Final,
97 },
98 {
99 "sha1", sizeof(SHA1_CTX), SHA1_DIGEST_LENGTH, SHA1_BLOCK_LENGTH,
100 (void *)SHA1Init, (void *)SHA1Update, (void *)SHA1Final,
101 },
102 {
103 "sha224", sizeof(SHA224_CTX), SHA224_DIGEST_LENGTH,
104 SHA224_BLOCK_LENGTH,
105 (void *)SHA224_Init, (void *)SHA224_Update,
106 (void *)SHA224_Final,
107 },
108 #endif
109 {
110 "sha256", sizeof(SHA256_CTX), SHA256_DIGEST_LENGTH,
111 SHA256_BLOCK_LENGTH,
112 (void *)SHA256_Init, (void *)SHA256_Update,
113 (void *)SHA256_Final,
114 },
115 #if 0
116 {
117 "sha384", sizeof(SHA384_CTX), SHA384_DIGEST_LENGTH,
118 SHA384_BLOCK_LENGTH,
119 (void *)SHA384_Init, (void *)SHA384_Update,
120 (void *)SHA384_Final,
121 },
122 {
123 "sha512", sizeof(SHA512_CTX), SHA512_DIGEST_LENGTH,
124 SHA512_BLOCK_LENGTH,
125 (void *)SHA512_Init, (void *)SHA512_Update,
126 (void *)SHA512_Final,
127 },
128 #endif
129 };
130
131 static const struct hmac *
hmac_find(const char * name)132 hmac_find(const char *name)
133 {
134 for (size_t i = 0; i < __arraycount(hmacs); i++) {
135 if (strcmp(hmacs[i].name, name) != 0)
136 continue;
137 return &hmacs[i];
138 }
139 return NULL;
140 }
141
142 ssize_t
hmac(const char * name,const void * key,size_t klen,const void * text,size_t tlen,void * digest,size_t dlen)143 hmac(const char *name,
144 const void *key, size_t klen,
145 const void *text, size_t tlen,
146 void *digest, size_t dlen)
147 {
148 uint8_t ipad[HMAC_SIZE], opad[HMAC_SIZE], d[HMAC_SIZE];
149 const uint8_t *k = key;
150 const struct hmac *h;
151 uint64_t c[32];
152 void *p;
153
154 if ((h = hmac_find(name)) == NULL)
155 return -1;
156
157
158 if (klen > h->blocksize) {
159 (*h->init)(c);
160 (*h->update)(c, k, (unsigned int)klen);
161 (*h->final)(d, c);
162 k = (void *)d;
163 klen = h->digsize;
164 }
165
166 /* Form input and output pads for the digests */
167 for (size_t i = 0; i < sizeof(ipad); i++) {
168 ipad[i] = (i < klen ? k[i] : 0) ^ HMAC_IPAD;
169 opad[i] = (i < klen ? k[i] : 0) ^ HMAC_OPAD;
170 }
171
172 p = dlen >= h->digsize ? digest : d;
173 if (p != digest) {
174 memcpy(p, digest, dlen);
175 memset((char *)p + dlen, 0, h->digsize - dlen);
176 }
177 (*h->init)(c);
178 (*h->update)(c, ipad, (unsigned int)h->blocksize);
179 (*h->update)(c, text, (unsigned int)tlen);
180 (*h->final)(p, c);
181
182 (*h->init)(c);
183 (*h->update)(c, opad, (unsigned int)h->blocksize);
184 (*h->update)(c, digest, (unsigned int)h->digsize);
185 (*h->final)(p, c);
186
187 if (p != digest)
188 memcpy(digest, p, dlen);
189
190 return (ssize_t)h->digsize;
191 }
192