1/* $OpenBSD: hmac.c,v 1.35 2024/06/01 07:36:16 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_local.h"
67#include "hmac_local.h"
68
69int
70HMAC_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;
134err:
135	return 0;
136}
137LCRYPTO_ALIAS(HMAC_Init_ex);
138
139int
140HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
141{
142	if (key && md)
143		HMAC_CTX_init(ctx);
144	return HMAC_Init_ex(ctx, key, len, md, NULL);
145}
146LCRYPTO_ALIAS(HMAC_Init);
147
148int
149HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
150{
151	if (ctx->md == NULL)
152		return 0;
153
154	return EVP_DigestUpdate(&ctx->md_ctx, data, len);
155}
156LCRYPTO_ALIAS(HMAC_Update);
157
158int
159HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
160{
161	unsigned int i;
162	unsigned char buf[EVP_MAX_MD_SIZE];
163
164	if (ctx->md == NULL)
165		goto err;
166
167	if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
168		goto err;
169	if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
170		goto err;
171	if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
172		goto err;
173	if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
174		goto err;
175	return 1;
176err:
177	return 0;
178}
179LCRYPTO_ALIAS(HMAC_Final);
180
181HMAC_CTX *
182HMAC_CTX_new(void)
183{
184	return calloc(1, sizeof(HMAC_CTX));
185}
186LCRYPTO_ALIAS(HMAC_CTX_new);
187
188void
189HMAC_CTX_free(HMAC_CTX *ctx)
190{
191	if (ctx == NULL)
192		return;
193
194	HMAC_CTX_cleanup(ctx);
195
196	free(ctx);
197}
198LCRYPTO_ALIAS(HMAC_CTX_free);
199
200int
201HMAC_CTX_reset(HMAC_CTX *ctx)
202{
203	HMAC_CTX_cleanup(ctx);
204	HMAC_CTX_init(ctx);
205	return 1;
206}
207LCRYPTO_ALIAS(HMAC_CTX_reset);
208
209void
210HMAC_CTX_init(HMAC_CTX *ctx)
211{
212	EVP_MD_CTX_legacy_clear(&ctx->i_ctx);
213	EVP_MD_CTX_legacy_clear(&ctx->o_ctx);
214	EVP_MD_CTX_legacy_clear(&ctx->md_ctx);
215	ctx->md = NULL;
216}
217
218int
219HMAC_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;
231err:
232	return 0;
233}
234LCRYPTO_ALIAS(HMAC_CTX_copy);
235
236void
237HMAC_CTX_cleanup(HMAC_CTX *ctx)
238{
239	EVP_MD_CTX_cleanup(&ctx->i_ctx);
240	EVP_MD_CTX_cleanup(&ctx->o_ctx);
241	EVP_MD_CTX_cleanup(&ctx->md_ctx);
242	explicit_bzero(ctx, sizeof(*ctx));
243}
244
245void
246HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
247{
248	EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
249	EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
250	EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
251}
252LCRYPTO_ALIAS(HMAC_CTX_set_flags);
253
254const EVP_MD *
255HMAC_CTX_get_md(const HMAC_CTX *ctx)
256{
257	return ctx->md;
258}
259LCRYPTO_ALIAS(HMAC_CTX_get_md);
260
261unsigned char *
262HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d,
263    size_t n, unsigned char *md, unsigned int *md_len)
264{
265	HMAC_CTX c;
266	const unsigned char dummy_key[1] = { 0 };
267
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;
281err:
282	HMAC_CTX_cleanup(&c);
283	return NULL;
284}
285LCRYPTO_ALIAS(HMAC);
286