1 /* $NetBSD: hmac.c,v 1.1.1.1 2011/04/13 18:14:50 elric Exp $ */
2
3 /*
4 * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
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 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <sys/types.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <hmac.h>
41
42 void
HMAC_CTX_init(HMAC_CTX * ctx)43 HMAC_CTX_init(HMAC_CTX *ctx)
44 {
45 memset(ctx, 0, sizeof(*ctx));
46 }
47
48 void
HMAC_CTX_cleanup(HMAC_CTX * ctx)49 HMAC_CTX_cleanup(HMAC_CTX *ctx)
50 {
51 if (ctx->buf) {
52 memset(ctx->buf, 0, ctx->key_length);
53 free(ctx->buf);
54 ctx->buf = NULL;
55 }
56 if (ctx->opad) {
57 memset(ctx->opad, 0, EVP_MD_block_size(ctx->md));
58 free(ctx->opad);
59 ctx->opad = NULL;
60 }
61 if (ctx->ipad) {
62 memset(ctx->ipad, 0, EVP_MD_block_size(ctx->md));
63 free(ctx->ipad);
64 ctx->ipad = NULL;
65 }
66 if (ctx->ctx) {
67 EVP_MD_CTX_destroy(ctx->ctx);
68 ctx->ctx = NULL;
69 }
70 }
71
72 size_t
HMAC_size(const HMAC_CTX * ctx)73 HMAC_size(const HMAC_CTX *ctx)
74 {
75 return EVP_MD_size(ctx->md);
76 }
77
78 void
HMAC_Init_ex(HMAC_CTX * ctx,const void * key,size_t keylen,const EVP_MD * md,ENGINE * engine)79 HMAC_Init_ex(HMAC_CTX *ctx,
80 const void *key,
81 size_t keylen,
82 const EVP_MD *md,
83 ENGINE *engine)
84 {
85 unsigned char *p;
86 size_t i;
87
88 if (ctx->md != md) {
89 ctx->md = md;
90 if (ctx->buf) {
91 memset(ctx->buf, 0, ctx->key_length);
92 free (ctx->buf);
93 }
94 ctx->key_length = EVP_MD_size(ctx->md);
95 ctx->buf = malloc(ctx->key_length);
96 }
97 #if 0
98 ctx->engine = engine;
99 #endif
100
101 if (keylen > EVP_MD_block_size(ctx->md)) {
102 EVP_Digest(key, keylen, ctx->buf, NULL, ctx->md, engine);
103 key = ctx->buf;
104 keylen = EVP_MD_size(ctx->md);
105 }
106
107 if (ctx->opad) {
108 memset(ctx->opad, 0, ctx->key_length);
109 free(ctx->opad);
110 }
111 if (ctx->ipad) {
112 memset(ctx->ipad, 0, ctx->key_length);
113 free(ctx->ipad);
114 }
115
116 ctx->opad = malloc(EVP_MD_block_size(ctx->md));
117 ctx->ipad = malloc(EVP_MD_block_size(ctx->md));
118 memset(ctx->ipad, 0x36, EVP_MD_block_size(ctx->md));
119 memset(ctx->opad, 0x5c, EVP_MD_block_size(ctx->md));
120
121 for (i = 0, p = ctx->ipad; i < keylen; i++)
122 p[i] ^= ((const unsigned char *)key)[i];
123 for (i = 0, p = ctx->opad; i < keylen; i++)
124 p[i] ^= ((const unsigned char *)key)[i];
125
126 if (ctx->ctx == NULL)
127 ctx->ctx = EVP_MD_CTX_create();
128
129 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine);
130 EVP_DigestUpdate(ctx->ctx, ctx->ipad, EVP_MD_block_size(ctx->md));
131 }
132
133 void
HMAC_Update(HMAC_CTX * ctx,const void * data,size_t len)134 HMAC_Update(HMAC_CTX *ctx, const void *data, size_t len)
135 {
136 EVP_DigestUpdate(ctx->ctx, data, len);
137 }
138
139 void
HMAC_Final(HMAC_CTX * ctx,void * md,unsigned int * len)140 HMAC_Final(HMAC_CTX *ctx, void *md, unsigned int *len)
141 {
142 EVP_DigestFinal_ex(ctx->ctx, ctx->buf, NULL);
143
144 EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine);
145 EVP_DigestUpdate(ctx->ctx, ctx->opad, EVP_MD_block_size(ctx->md));
146 EVP_DigestUpdate(ctx->ctx, ctx->buf, ctx->key_length);
147 EVP_DigestFinal_ex(ctx->ctx, md, len);
148 }
149
150 void *
HMAC(const EVP_MD * md,const void * key,size_t key_size,const void * data,size_t data_size,void * hash,unsigned int * hash_len)151 HMAC(const EVP_MD *md,
152 const void *key, size_t key_size,
153 const void *data, size_t data_size,
154 void *hash, unsigned int *hash_len)
155 {
156 HMAC_CTX ctx;
157
158 HMAC_CTX_init(&ctx);
159 HMAC_Init_ex(&ctx, key, key_size, md, NULL);
160 HMAC_Update(&ctx, data, data_size);
161 HMAC_Final(&ctx, hash, hash_len);
162 HMAC_CTX_cleanup(&ctx);
163 return hash;
164 }
165