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1 /* | |
2 * hmac.c | |
3 * | |
4 * implementation of hmac auth_type_t | |
5 * | |
6 * David A. McGrew | |
7 * Cisco Systems, Inc. | |
8 */ | |
9 /* | |
10 * | |
11 * Copyright(c) 2001-2006 Cisco Systems, Inc. | |
12 * All rights reserved. | |
13 * | |
14 * Redistribution and use in source and binary forms, with or without | |
15 * modification, are permitted provided that the following conditions | |
16 * are met: | |
17 * | |
18 * Redistributions of source code must retain the above copyright | |
19 * notice, this list of conditions and the following disclaimer. | |
20 * | |
21 * Redistributions in binary form must reproduce the above | |
22 * copyright notice, this list of conditions and the following | |
23 * disclaimer in the documentation and/or other materials provided | |
24 * with the distribution. | |
25 * | |
26 * Neither the name of the Cisco Systems, Inc. nor the names of its | |
27 * contributors may be used to endorse or promote products derived | |
28 * from this software without specific prior written permission. | |
29 * | |
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
34 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, | |
35 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
36 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
37 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
41 * OF THE POSSIBILITY OF SUCH DAMAGE. | |
42 * | |
43 */ | |
44 | |
45 #ifdef HAVE_CONFIG_H | |
46 #include <config.h> | |
47 #endif | |
48 | |
49 #include "hmac.h" | |
50 #include "alloc.h" | |
51 | |
52 /* the debug module for authentiation */ | |
53 | |
54 debug_module_t mod_hmac = { | |
55 0, /* debugging is off by default */ | |
56 "hmac sha-1" /* printable name for module */ | |
57 }; | |
58 | |
59 | |
60 err_status_t | |
61 hmac_alloc(auth_t **a, int key_len, int out_len) { | |
62 extern auth_type_t hmac; | |
63 uint8_t *pointer; | |
64 | |
65 debug_print(mod_hmac, "allocating auth func with key length %d", key_len); | |
66 debug_print(mod_hmac, " tag length %d", out_len); | |
67 | |
68 /* | |
69 * check key length - note that we don't support keys larger | |
70 * than 20 bytes yet | |
71 */ | |
72 if (key_len > 20) | |
73 return err_status_bad_param; | |
74 | |
75 /* check output length - should be less than 20 bytes */ | |
76 if (out_len > 20) | |
77 return err_status_bad_param; | |
78 | |
79 /* allocate memory for auth and hmac_ctx_t structures */ | |
80 pointer = (uint8_t*)crypto_alloc(sizeof(hmac_ctx_t) + sizeof(auth_t)); | |
81 if (pointer == NULL) | |
82 return err_status_alloc_fail; | |
83 | |
84 /* set pointers */ | |
85 *a = (auth_t *)pointer; | |
86 (*a)->type = &hmac; | |
87 (*a)->state = pointer + sizeof(auth_t); | |
88 (*a)->out_len = out_len; | |
89 (*a)->key_len = key_len; | |
90 (*a)->prefix_len = 0; | |
91 | |
92 /* increment global count of all hmac uses */ | |
93 hmac.ref_count++; | |
94 | |
95 return err_status_ok; | |
96 } | |
97 | |
98 err_status_t | |
99 hmac_dealloc(auth_t *a) { | |
100 extern auth_type_t hmac; | |
101 | |
102 /* zeroize entire state*/ | |
103 octet_string_set_to_zero((uint8_t *)a, | |
104 sizeof(hmac_ctx_t) + sizeof(auth_t)); | |
105 | |
106 /* free memory */ | |
107 crypto_free(a); | |
108 | |
109 /* decrement global count of all hmac uses */ | |
110 hmac.ref_count--; | |
111 | |
112 return err_status_ok; | |
113 } | |
114 | |
115 err_status_t | |
116 hmac_init(hmac_ctx_t *state, const uint8_t *key, int key_len) { | |
117 int i; | |
118 uint8_t ipad[64]; | |
119 | |
120 /* | |
121 * check key length - note that we don't support keys larger | |
122 * than 20 bytes yet | |
123 */ | |
124 if (key_len > 20) | |
125 return err_status_bad_param; | |
126 | |
127 /* | |
128 * set values of ipad and opad by exoring the key into the | |
129 * appropriate constant values | |
130 */ | |
131 for (i=0; i < key_len; i++) { | |
132 ipad[i] = key[i] ^ 0x36; | |
133 state->opad[i] = key[i] ^ 0x5c; | |
134 } | |
135 /* set the rest of ipad, opad to constant values */ | |
136 for ( ; i < 64; i++) { | |
137 ipad[i] = 0x36; | |
138 ((uint8_t *)state->opad)[i] = 0x5c; | |
139 } | |
140 | |
141 debug_print(mod_hmac, "ipad: %s", octet_string_hex_string(ipad, 64)); | |
142 | |
143 /* initialize sha1 context */ | |
144 sha1_init(&state->init_ctx); | |
145 | |
146 /* hash ipad ^ key */ | |
147 sha1_update(&state->init_ctx, ipad, 64); | |
148 memcpy(&state->ctx, &state->init_ctx, sizeof(sha1_ctx_t)); | |
149 | |
150 return err_status_ok; | |
151 } | |
152 | |
153 err_status_t | |
154 hmac_start(hmac_ctx_t *state) { | |
155 | |
156 memcpy(&state->ctx, &state->init_ctx, sizeof(sha1_ctx_t)); | |
157 | |
158 return err_status_ok; | |
159 } | |
160 | |
161 err_status_t | |
162 hmac_update(hmac_ctx_t *state, const uint8_t *message, int msg_octets) { | |
163 | |
164 debug_print(mod_hmac, "input: %s", | |
165 octet_string_hex_string(message, msg_octets)); | |
166 | |
167 /* hash message into sha1 context */ | |
168 sha1_update(&state->ctx, message, msg_octets); | |
169 | |
170 return err_status_ok; | |
171 } | |
172 | |
173 err_status_t | |
174 hmac_compute(hmac_ctx_t *state, const void *message, | |
175 int msg_octets, int tag_len, uint8_t *result) { | |
176 uint32_t hash_value[5]; | |
177 uint32_t H[5]; | |
178 int i; | |
179 | |
180 /* check tag length, return error if we can't provide the value expected */ | |
181 if (tag_len > 20) | |
182 return err_status_bad_param; | |
183 | |
184 /* hash message, copy output into H */ | |
185 hmac_update(state, (const uint8_t*)message, msg_octets); | |
186 sha1_final(&state->ctx, H); | |
187 | |
188 /* | |
189 * note that we don't need to debug_print() the input, since the | |
190 * function hmac_update() already did that for us | |
191 */ | |
192 debug_print(mod_hmac, "intermediate state: %s", | |
193 octet_string_hex_string((uint8_t *)H, 20)); | |
194 | |
195 /* re-initialize hash context */ | |
196 sha1_init(&state->ctx); | |
197 | |
198 /* hash opad ^ key */ | |
199 sha1_update(&state->ctx, (uint8_t *)state->opad, 64); | |
200 | |
201 /* hash the result of the inner hash */ | |
202 sha1_update(&state->ctx, (uint8_t *)H, 20); | |
203 | |
204 /* the result is returned in the array hash_value[] */ | |
205 sha1_final(&state->ctx, hash_value); | |
206 | |
207 /* copy hash_value to *result */ | |
208 for (i=0; i < tag_len; i++) | |
209 result[i] = ((uint8_t *)hash_value)[i]; | |
210 | |
211 debug_print(mod_hmac, "output: %s", | |
212 octet_string_hex_string((uint8_t *)hash_value, tag_len)); | |
213 | |
214 return err_status_ok; | |
215 } | |
216 | |
217 | |
218 /* begin test case 0 */ | |
219 | |
220 uint8_t | |
221 hmac_test_case_0_key[20] = { | |
222 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, | |
223 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, | |
224 0x0b, 0x0b, 0x0b, 0x0b | |
225 }; | |
226 | |
227 uint8_t | |
228 hmac_test_case_0_data[8] = { | |
229 0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65 /* "Hi There" */ | |
230 }; | |
231 | |
232 uint8_t | |
233 hmac_test_case_0_tag[20] = { | |
234 0xb6, 0x17, 0x31, 0x86, 0x55, 0x05, 0x72, 0x64, | |
235 0xe2, 0x8b, 0xc0, 0xb6, 0xfb, 0x37, 0x8c, 0x8e, | |
236 0xf1, 0x46, 0xbe, 0x00 | |
237 }; | |
238 | |
239 auth_test_case_t | |
240 hmac_test_case_0 = { | |
241 20, /* octets in key */ | |
242 hmac_test_case_0_key, /* key */ | |
243 8, /* octets in data */ | |
244 hmac_test_case_0_data, /* data */ | |
245 20, /* octets in tag */ | |
246 hmac_test_case_0_tag, /* tag */ | |
247 NULL /* pointer to next testcase */ | |
248 }; | |
249 | |
250 /* end test case 0 */ | |
251 | |
252 char hmac_description[] = "hmac sha-1 authentication function"; | |
253 | |
254 /* | |
255 * auth_type_t hmac is the hmac metaobject | |
256 */ | |
257 | |
258 auth_type_t | |
259 hmac = { | |
260 (auth_alloc_func) hmac_alloc, | |
261 (auth_dealloc_func) hmac_dealloc, | |
262 (auth_init_func) hmac_init, | |
263 (auth_compute_func) hmac_compute, | |
264 (auth_update_func) hmac_update, | |
265 (auth_start_func) hmac_start, | |
266 (char *) hmac_description, | |
267 (int) 0, /* instance count */ | |
268 (auth_test_case_t *) &hmac_test_case_0, | |
269 (debug_module_t *) &mod_hmac, | |
270 (auth_type_id_t) HMAC_SHA1 | |
271 }; | |
272 | |
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