1 /* crypto/cmac/cmac.c */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project.
4 */
5 /* ====================================================================
6 * Copyright (c) 2010 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 */
53
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include "cryptlib.h"
58 #include <openssl/cmac.h>
59
60 #ifdef OPENSSL_FIPS
61 #include <openssl/fips.h>
62 #endif
63
64 struct CMAC_CTX_st
65 {
66 /* Cipher context to use */
67 EVP_CIPHER_CTX cctx;
68 /* Keys k1 and k2 */
69 unsigned char k1[EVP_MAX_BLOCK_LENGTH];
70 unsigned char k2[EVP_MAX_BLOCK_LENGTH];
71 /* Temporary block */
72 unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
73 /* Last (possibly partial) block */
74 unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
75 /* Number of bytes in last block: -1 means context not initialised */
76 int nlast_block;
77 };
78
79
80 /* Make temporary keys K1 and K2 */
81
82 static void make_kn(unsigned char *k1, unsigned char *l, int bl)
83 {
84 int i;
85 /* Shift block to left, including carry */
86 for (i = 0; i < bl; i++)
87 {
88 k1[i] = l[i] << 1;
89 if (i < bl - 1 && l[i + 1] & 0x80)
90 k1[i] |= 1;
91 }
92 /* If MSB set fixup with R */
93 if (l[0] & 0x80)
94 k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
95 }
96
97 CMAC_CTX *CMAC_CTX_new(void)
98 {
99 CMAC_CTX *ctx;
100 ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
101 if (!ctx)
102 return NULL;
103 EVP_CIPHER_CTX_init(&ctx->cctx);
104 ctx->nlast_block = -1;
105 return ctx;
106 }
107
108 void CMAC_CTX_cleanup(CMAC_CTX *ctx)
109 {
110 #ifdef OPENSSL_FIPS
111 if (FIPS_mode() && !ctx->cctx.engine)
112 {
113 FIPS_cmac_ctx_cleanup(ctx);
114 return;
115 }
116 #endif
117 EVP_CIPHER_CTX_cleanup(&ctx->cctx);
118 OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
119 OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
120 OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
121 OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
122 ctx->nlast_block = -1;
123 }
124
125 EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
126 {
127 return &ctx->cctx;
128 }
129
130 void CMAC_CTX_free(CMAC_CTX *ctx)
131 {
132 CMAC_CTX_cleanup(ctx);
133 OPENSSL_free(ctx);
134 }
135
136 int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
137 {
138 int bl;
139 if (in->nlast_block == -1)
140 return 0;
141 if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
142 return 0;
143 bl = EVP_CIPHER_CTX_block_size(&in->cctx);
144 memcpy(out->k1, in->k1, bl);
145 memcpy(out->k2, in->k2, bl);
146 memcpy(out->tbl, in->tbl, bl);
147 memcpy(out->last_block, in->last_block, bl);
148 out->nlast_block = in->nlast_block;
149 return 1;
150 }
151
152 int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
153 const EVP_CIPHER *cipher, ENGINE *impl)
154 {
155 static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
156 #ifdef OPENSSL_FIPS
157 if (FIPS_mode())
158 {
159 /* If we have an ENGINE need to allow non FIPS */
160 if ((impl || ctx->cctx.engine)
161 && !(ctx->cctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW))
162
163 {
164 EVPerr(EVP_F_CMAC_INIT, EVP_R_DISABLED_FOR_FIPS);
165 return 0;
166 }
167 /* Other algorithm blocking will be done in FIPS_cmac_init,
168 * via FIPS_cipherinit().
169 */
170 if (!impl && !ctx->cctx.engine)
171 return FIPS_cmac_init(ctx, key, keylen, cipher, NULL);
172 }
173 #endif
174 /* All zeros means restart */
175 if (!key && !cipher && !impl && keylen == 0)
176 {
177 /* Not initialised */
178 if (ctx->nlast_block == -1)
179 return 0;
180 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
181 return 0;
182 memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(&ctx->cctx));
183 ctx->nlast_block = 0;
184 return 1;
185 }
186 /* Initialiase context */
187 if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
188 return 0;
189 /* Non-NULL key means initialisation complete */
190 if (key)
191 {
192 int bl;
193 if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
194 return 0;
195 if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
196 return 0;
197 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
198 return 0;
199 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
200 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
201 return 0;
202 make_kn(ctx->k1, ctx->tbl, bl);
203 make_kn(ctx->k2, ctx->k1, bl);
204 OPENSSL_cleanse(ctx->tbl, bl);
205 /* Reset context again ready for first data block */
206 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
207 return 0;
208 /* Zero tbl so resume works */
209 memset(ctx->tbl, 0, bl);
210 ctx->nlast_block = 0;
211 }
212 return 1;
213 }
214
215 int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
216 {
217 const unsigned char *data = in;
218 size_t bl;
219 #ifdef OPENSSL_FIPS
220 if (FIPS_mode() && !ctx->cctx.engine)
221 return FIPS_cmac_update(ctx, in, dlen);
222 #endif
223 if (ctx->nlast_block == -1)
224 return 0;
225 if (dlen == 0)
226 return 1;
227 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
228 /* Copy into partial block if we need to */
229 if (ctx->nlast_block > 0)
230 {
231 size_t nleft;
232 nleft = bl - ctx->nlast_block;
233 if (dlen < nleft)
234 nleft = dlen;
235 memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
236 dlen -= nleft;
237 ctx->nlast_block += nleft;
238 /* If no more to process return */
239 if (dlen == 0)
240 return 1;
241 data += nleft;
242 /* Else not final block so encrypt it */
243 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block,bl))
244 return 0;
245 }
246 /* Encrypt all but one of the complete blocks left */
247 while(dlen > bl)
248 {
249 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
250 return 0;
251 dlen -= bl;
252 data += bl;
253 }
254 /* Copy any data left to last block buffer */
255 memcpy(ctx->last_block, data, dlen);
256 ctx->nlast_block = dlen;
257 return 1;
258
259 }
260
261 int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
262 {
263 int i, bl, lb;
264 #ifdef OPENSSL_FIPS
265 if (FIPS_mode() && !ctx->cctx.engine)
266 return FIPS_cmac_final(ctx, out, poutlen);
267 #endif
268 if (ctx->nlast_block == -1)
269 return 0;
270 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
271 *poutlen = (size_t)bl;
272 if (!out)
273 return 1;
274 lb = ctx->nlast_block;
275 /* Is last block complete? */
276 if (lb == bl)
277 {
278 for (i = 0; i < bl; i++)
279 out[i] = ctx->last_block[i] ^ ctx->k1[i];
280 }
281 else
282 {
283 ctx->last_block[lb] = 0x80;
284 if (bl - lb > 1)
285 memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
286 for (i = 0; i < bl; i++)
287 out[i] = ctx->last_block[i] ^ ctx->k2[i];
288 }
289 if (!EVP_Cipher(&ctx->cctx, out, out, bl))
290 {
291 OPENSSL_cleanse(out, bl);
292 return 0;
293 }
294 return 1;
295 }
296
297 int CMAC_resume(CMAC_CTX *ctx)
298 {
299 if (ctx->nlast_block == -1)
300 return 0;
301 /* The buffer "tbl" containes the last fully encrypted block
302 * which is the last IV (or all zeroes if no last encrypted block).
303 * The last block has not been modified since CMAC_final().
304 * So reinitliasing using the last decrypted block will allow
305 * CMAC to continue after calling CMAC_Final().
306 */
307 return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);
308 }