1 /* $OpenBSD: hmac.c,v 1.28 2022/05/05 18:29:34 tb Exp $ */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62
63 #include <openssl/err.h>
64 #include <openssl/hmac.h>
65
66 #include "evp_locl.h"
67 #include "hmac_local.h"
68
69 int
HMAC_Init_ex(HMAC_CTX * ctx,const void * key,int len,const EVP_MD * md,ENGINE * impl)70 HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md,
71 ENGINE *impl)
72 {
73 int i, j, reset = 0;
74 unsigned char pad[HMAC_MAX_MD_CBLOCK];
75
76 /* If we are changing MD then we must have a key */
77 if (md != NULL && md != ctx->md && (key == NULL || len < 0))
78 return 0;
79
80 if (md != NULL) {
81 reset = 1;
82 ctx->md = md;
83 } else if (ctx->md != NULL)
84 md = ctx->md;
85 else
86 return 0;
87
88 if (key != NULL) {
89 reset = 1;
90 j = EVP_MD_block_size(md);
91 if ((size_t)j > sizeof(ctx->key)) {
92 EVPerror(EVP_R_BAD_BLOCK_LENGTH);
93 goto err;
94 }
95 if (j < len) {
96 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
97 goto err;
98 if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
99 goto err;
100 if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
101 &ctx->key_length))
102 goto err;
103 } else {
104 if (len < 0 || (size_t)len > sizeof(ctx->key)) {
105 EVPerror(EVP_R_BAD_KEY_LENGTH);
106 goto err;
107 }
108 memcpy(ctx->key, key, len);
109 ctx->key_length = len;
110 }
111 if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
112 memset(&ctx->key[ctx->key_length], 0,
113 HMAC_MAX_MD_CBLOCK - ctx->key_length);
114 }
115
116 if (reset) {
117 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
118 pad[i] = 0x36 ^ ctx->key[i];
119 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
120 goto err;
121 if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md)))
122 goto err;
123
124 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
125 pad[i] = 0x5c ^ ctx->key[i];
126 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
127 goto err;
128 if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md)))
129 goto err;
130 }
131 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
132 goto err;
133 return 1;
134 err:
135 return 0;
136 }
137
138 int
HMAC_Init(HMAC_CTX * ctx,const void * key,int len,const EVP_MD * md)139 HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
140 {
141 if (key && md)
142 HMAC_CTX_init(ctx);
143 return HMAC_Init_ex(ctx, key, len, md, NULL);
144 }
145
146 int
HMAC_Update(HMAC_CTX * ctx,const unsigned char * data,size_t len)147 HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
148 {
149 if (ctx->md == NULL)
150 return 0;
151
152 return EVP_DigestUpdate(&ctx->md_ctx, data, len);
153 }
154
155 int
HMAC_Final(HMAC_CTX * ctx,unsigned char * md,unsigned int * len)156 HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
157 {
158 unsigned int i;
159 unsigned char buf[EVP_MAX_MD_SIZE];
160
161 if (ctx->md == NULL)
162 goto err;
163
164 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
165 goto err;
166 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
167 goto err;
168 if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
169 goto err;
170 if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
171 goto err;
172 return 1;
173 err:
174 return 0;
175 }
176
177 HMAC_CTX *
HMAC_CTX_new(void)178 HMAC_CTX_new(void)
179 {
180 HMAC_CTX *ctx;
181
182 if ((ctx = calloc(1, sizeof(*ctx))) == NULL)
183 return NULL;
184
185 HMAC_CTX_init(ctx);
186
187 return ctx;
188 }
189
190 void
HMAC_CTX_free(HMAC_CTX * ctx)191 HMAC_CTX_free(HMAC_CTX *ctx)
192 {
193 if (ctx == NULL)
194 return;
195
196 HMAC_CTX_cleanup(ctx);
197
198 free(ctx);
199 }
200
201 int
HMAC_CTX_reset(HMAC_CTX * ctx)202 HMAC_CTX_reset(HMAC_CTX *ctx)
203 {
204 HMAC_CTX_cleanup(ctx);
205 HMAC_CTX_init(ctx);
206 return 1;
207 }
208
209 void
HMAC_CTX_init(HMAC_CTX * ctx)210 HMAC_CTX_init(HMAC_CTX *ctx)
211 {
212 EVP_MD_CTX_init(&ctx->i_ctx);
213 EVP_MD_CTX_init(&ctx->o_ctx);
214 EVP_MD_CTX_init(&ctx->md_ctx);
215 ctx->md = NULL;
216 }
217
218 int
HMAC_CTX_copy(HMAC_CTX * dctx,HMAC_CTX * sctx)219 HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
220 {
221 if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx))
222 goto err;
223 if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx))
224 goto err;
225 if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx))
226 goto err;
227 memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
228 dctx->key_length = sctx->key_length;
229 dctx->md = sctx->md;
230 return 1;
231 err:
232 return 0;
233 }
234
235 void
HMAC_CTX_cleanup(HMAC_CTX * ctx)236 HMAC_CTX_cleanup(HMAC_CTX *ctx)
237 {
238 EVP_MD_CTX_cleanup(&ctx->i_ctx);
239 EVP_MD_CTX_cleanup(&ctx->o_ctx);
240 EVP_MD_CTX_cleanup(&ctx->md_ctx);
241 explicit_bzero(ctx, sizeof(*ctx));
242 }
243
244 void
HMAC_CTX_set_flags(HMAC_CTX * ctx,unsigned long flags)245 HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
246 {
247 EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
248 EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
249 EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
250 }
251
252 const EVP_MD *
HMAC_CTX_get_md(const HMAC_CTX * ctx)253 HMAC_CTX_get_md(const HMAC_CTX *ctx)
254 {
255 return ctx->md;
256 }
257
258 unsigned char *
HMAC(const EVP_MD * evp_md,const void * key,int key_len,const unsigned char * d,size_t n,unsigned char * md,unsigned int * md_len)259 HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d,
260 size_t n, unsigned char *md, unsigned int *md_len)
261 {
262 HMAC_CTX c;
263 static unsigned char m[EVP_MAX_MD_SIZE];
264 const unsigned char dummy_key[1] = { 0 };
265
266 if (md == NULL)
267 md = m;
268 if (key == NULL) {
269 key = dummy_key;
270 key_len = 0;
271 }
272 HMAC_CTX_init(&c);
273 if (!HMAC_Init_ex(&c, key, key_len, evp_md, NULL))
274 goto err;
275 if (!HMAC_Update(&c, d, n))
276 goto err;
277 if (!HMAC_Final(&c, md, md_len))
278 goto err;
279 HMAC_CTX_cleanup(&c);
280 return md;
281 err:
282 HMAC_CTX_cleanup(&c);
283 return NULL;
284 }
285