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