1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57#include <openssl/hmac.h>
58
59#include <assert.h>
60#include <string.h>
61
62#include <openssl/digest.h>
63#include <openssl/mem.h>
64
65#include "../../internal.h"
66
67
68uint8_t *HMAC(const EVP_MD *evp_md, const void *key, size_t key_len,
69 const uint8_t *data, size_t data_len, uint8_t *out,
70 unsigned int *out_len) {
71 HMAC_CTX ctx;
72 HMAC_CTX_init(&ctx);
73 if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) ||
74 !HMAC_Update(&ctx, data, data_len) ||
75 !HMAC_Final(&ctx, out, out_len)) {
76 out = NULL;
77 }
78
79 HMAC_CTX_cleanup(&ctx);
80 return out;
81}
82
83void HMAC_CTX_init(HMAC_CTX *ctx) {
84 ctx->md = NULL;
85 EVP_MD_CTX_init(&ctx->i_ctx);
86 EVP_MD_CTX_init(&ctx->o_ctx);
87 EVP_MD_CTX_init(&ctx->md_ctx);
88}
89
90HMAC_CTX *HMAC_CTX_new(void) {
91 HMAC_CTX *ctx = OPENSSL_malloc(sizeof(HMAC_CTX));
92 if (ctx != NULL) {
93 HMAC_CTX_init(ctx);
94 }
95 return ctx;
96}
97
98void HMAC_CTX_cleanup(HMAC_CTX *ctx) {
99 EVP_MD_CTX_cleanup(&ctx->i_ctx);
100 EVP_MD_CTX_cleanup(&ctx->o_ctx);
101 EVP_MD_CTX_cleanup(&ctx->md_ctx);
102 OPENSSL_cleanse(ctx, sizeof(HMAC_CTX));
103}
104
105void HMAC_CTX_free(HMAC_CTX *ctx) {
106 if (ctx == NULL) {
107 return;
108 }
109
110 HMAC_CTX_cleanup(ctx);
111 OPENSSL_free(ctx);
112}
113
114int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len,
115 const EVP_MD *md, ENGINE *impl) {
116 if (md == NULL) {
117 md = ctx->md;
118 }
119
120 // If either |key| is non-NULL or |md| has changed, initialize with a new key
121 // rather than rewinding the previous one.
122 //
123 // TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is
124 // ambiguous between using the empty key and reusing the previous key. There
125 // exist callers which intend the latter, but the former is an awkward edge
126 // case. Fix to API to avoid this.
127 if (md != ctx->md || key != NULL) {
128 uint8_t pad[EVP_MAX_MD_BLOCK_SIZE];
129 uint8_t key_block[EVP_MAX_MD_BLOCK_SIZE];
130 unsigned key_block_len;
131
132 size_t block_size = EVP_MD_block_size(md);
133 assert(block_size <= sizeof(key_block));
134 if (block_size < key_len) {
135 // Long keys are hashed.
136 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) ||
137 !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) ||
138 !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) {
139 return 0;
140 }
141 } else {
142 assert(key_len <= sizeof(key_block));
143 OPENSSL_memcpy(key_block, key, key_len);
144 key_block_len = (unsigned)key_len;
145 }
146 // Keys are then padded with zeros.
147 if (key_block_len != EVP_MAX_MD_BLOCK_SIZE) {
148 OPENSSL_memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len);
149 }
150
151 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) {
152 pad[i] = 0x36 ^ key_block[i];
153 }
154 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) ||
155 !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) {
156 return 0;
157 }
158
159 for (size_t i = 0; i < EVP_MAX_MD_BLOCK_SIZE; i++) {
160 pad[i] = 0x5c ^ key_block[i];
161 }
162 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) ||
163 !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) {
164 return 0;
165 }
166
167 ctx->md = md;
168 }
169
170 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) {
171 return 0;
172 }
173
174 return 1;
175}
176
177int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) {
178 return EVP_DigestUpdate(&ctx->md_ctx, data, data_len);
179}
180
181int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) {
182 unsigned int i;
183 uint8_t buf[EVP_MAX_MD_SIZE];
184
185 // TODO(davidben): The only thing that can officially fail here is
186 // |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case.
187 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) ||
188 !EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) ||
189 !EVP_DigestUpdate(&ctx->md_ctx, buf, i) ||
190 !EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) {
191 *out_len = 0;
192 return 0;
193 }
194
195 return 1;
196}
197
198size_t HMAC_size(const HMAC_CTX *ctx) {
199 return EVP_MD_size(ctx->md);
200}
201
202int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) {
203 if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) ||
204 !EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) ||
205 !EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) {
206 return 0;
207 }
208
209 dest->md = src->md;
210 return 1;
211}
212
213void HMAC_CTX_reset(HMAC_CTX *ctx) {
214 HMAC_CTX_cleanup(ctx);
215 HMAC_CTX_init(ctx);
216}
217
218int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) {
219 if (key && md) {
220 HMAC_CTX_init(ctx);
221 }
222 return HMAC_Init_ex(ctx, key, key_len, md, NULL);
223}
224
225int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) {
226 HMAC_CTX_init(dest);
227 return HMAC_CTX_copy_ex(dest, src);
228}
229