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/mem.h>
63
64
HMAC(const EVP_MD * evp_md,const void * key,size_t key_len,const uint8_t * data,size_t data_len,uint8_t * out,unsigned int * out_len)65 uint8_t *HMAC(const EVP_MD *evp_md, const void *key, size_t key_len,
66 const uint8_t *data, size_t data_len, uint8_t *out,
67 unsigned int *out_len) {
68 HMAC_CTX ctx;
69 static uint8_t static_out_buffer[EVP_MAX_MD_SIZE];
70
71 /* OpenSSL has traditionally supported using a static buffer if |out| is
72 * NULL. We maintain that but don't document it. This behaviour should be
73 * considered to be deprecated. */
74 if (out == NULL) {
75 out = static_out_buffer;
76 }
77
78 HMAC_CTX_init(&ctx);
79 if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) ||
80 !HMAC_Update(&ctx, data, data_len) ||
81 !HMAC_Final(&ctx, out, out_len)) {
82 out = NULL;
83 }
84
85 HMAC_CTX_cleanup(&ctx);
86 return out;
87 }
88
HMAC_CTX_init(HMAC_CTX * ctx)89 void HMAC_CTX_init(HMAC_CTX *ctx) {
90 ctx->md = NULL;
91 EVP_MD_CTX_init(&ctx->i_ctx);
92 EVP_MD_CTX_init(&ctx->o_ctx);
93 EVP_MD_CTX_init(&ctx->md_ctx);
94 }
95
HMAC_CTX_cleanup(HMAC_CTX * ctx)96 void HMAC_CTX_cleanup(HMAC_CTX *ctx) {
97 EVP_MD_CTX_cleanup(&ctx->i_ctx);
98 EVP_MD_CTX_cleanup(&ctx->o_ctx);
99 EVP_MD_CTX_cleanup(&ctx->md_ctx);
100 OPENSSL_cleanse(ctx, sizeof(HMAC_CTX));
101 }
102
HMAC_Init_ex(HMAC_CTX * ctx,const void * key,size_t key_len,const EVP_MD * md,ENGINE * impl)103 int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len,
104 const EVP_MD *md, ENGINE *impl) {
105 if (md == NULL) {
106 md = ctx->md;
107 }
108
109 /* If either |key| is non-NULL or |md| has changed, initialize with a new key
110 * rather than rewinding the previous one.
111 *
112 * TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is
113 * ambiguous between using the empty key and reusing the previous key. There
114 * exist callers which intend the latter, but the former is an awkward edge
115 * case. Fix to API to avoid this. */
116 if (md != ctx->md || key != NULL) {
117 size_t i;
118 uint8_t pad[HMAC_MAX_MD_CBLOCK];
119 uint8_t key_block[HMAC_MAX_MD_CBLOCK];
120 unsigned key_block_len;
121
122 size_t block_size = EVP_MD_block_size(md);
123 assert(block_size <= sizeof(key_block));
124 if (block_size < key_len) {
125 /* Long keys are hashed. */
126 if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) ||
127 !EVP_DigestUpdate(&ctx->md_ctx, key, key_len) ||
128 !EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) {
129 return 0;
130 }
131 } else {
132 assert(key_len <= sizeof(key_block));
133 memcpy(key_block, key, key_len);
134 key_block_len = (unsigned)key_len;
135 }
136 /* Keys are then padded with zeros. */
137 if (key_block_len != HMAC_MAX_MD_CBLOCK) {
138 memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len);
139 }
140
141 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) {
142 pad[i] = 0x36 ^ key_block[i];
143 }
144 if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) ||
145 !EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) {
146 return 0;
147 }
148
149 for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) {
150 pad[i] = 0x5c ^ key_block[i];
151 }
152 if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) ||
153 !EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) {
154 return 0;
155 }
156
157 ctx->md = md;
158 }
159
160 if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) {
161 return 0;
162 }
163
164 return 1;
165 }
166
HMAC_Update(HMAC_CTX * ctx,const uint8_t * data,size_t data_len)167 int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) {
168 return EVP_DigestUpdate(&ctx->md_ctx, data, data_len);
169 }
170
HMAC_Final(HMAC_CTX * ctx,uint8_t * out,unsigned int * out_len)171 int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) {
172 unsigned int i;
173 uint8_t buf[EVP_MAX_MD_SIZE];
174
175 /* TODO(davidben): The only thing that can officially fail here is
176 * |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case. */
177 if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) ||
178 !EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) ||
179 !EVP_DigestUpdate(&ctx->md_ctx, buf, i) ||
180 !EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) {
181 *out_len = 0;
182 return 0;
183 }
184
185 return 1;
186 }
187
HMAC_size(const HMAC_CTX * ctx)188 size_t HMAC_size(const HMAC_CTX *ctx) {
189 return EVP_MD_size(ctx->md);
190 }
191
HMAC_CTX_copy_ex(HMAC_CTX * dest,const HMAC_CTX * src)192 int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) {
193 if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) ||
194 !EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) ||
195 !EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) {
196 return 0;
197 }
198
199 dest->md = src->md;
200 return 1;
201 }
202
HMAC_Init(HMAC_CTX * ctx,const void * key,int key_len,const EVP_MD * md)203 int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) {
204 if (key && md) {
205 HMAC_CTX_init(ctx);
206 }
207 return HMAC_Init_ex(ctx, key, key_len, md, NULL);
208 }
209
HMAC_CTX_copy(HMAC_CTX * dest,const HMAC_CTX * src)210 int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) {
211 HMAC_CTX_init(dest);
212 return HMAC_CTX_copy_ex(dest, src);
213 }
214