1 /* crypto/cmac/cmac.c */
3 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
6 /* ====================================================================
7 * Copyright (c) 2010 The OpenSSL Project. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
35 * 6. Redistributions of any form whatsoever must retain the following
37 * "This product includes software developed by the OpenSSL Project
38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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;
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52 * ====================================================================
59 #include <openssl/cmac.h>
62 # include <openssl/fips.h>
66 /* Cipher context to use */
69 unsigned char k1[EVP_MAX_BLOCK_LENGTH];
70 unsigned char k2[EVP_MAX_BLOCK_LENGTH];
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 */
79 /* Make temporary keys K1 and K2 */
81 static void make_kn(unsigned char *k1, unsigned char *l, int bl)
84 /* Shift block to left, including carry */
85 for (i = 0; i < bl; i++) {
87 if (i < bl - 1 && l[i + 1] & 0x80)
90 /* If MSB set fixup with R */
92 k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
95 CMAC_CTX *CMAC_CTX_new(void)
98 ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
101 EVP_CIPHER_CTX_init(&ctx->cctx);
102 ctx->nlast_block = -1;
106 void CMAC_CTX_cleanup(CMAC_CTX *ctx)
109 if (FIPS_mode() && !ctx->cctx.engine) {
110 FIPS_cmac_ctx_cleanup(ctx);
114 EVP_CIPHER_CTX_cleanup(&ctx->cctx);
115 OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
116 OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
117 OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
118 OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
119 ctx->nlast_block = -1;
122 EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
127 void CMAC_CTX_free(CMAC_CTX *ctx)
131 CMAC_CTX_cleanup(ctx);
135 int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
138 if (in->nlast_block == -1)
140 if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
142 bl = EVP_CIPHER_CTX_block_size(&in->cctx);
143 memcpy(out->k1, in->k1, bl);
144 memcpy(out->k2, in->k2, bl);
145 memcpy(out->tbl, in->tbl, bl);
146 memcpy(out->last_block, in->last_block, bl);
147 out->nlast_block = in->nlast_block;
151 int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
152 const EVP_CIPHER *cipher, ENGINE *impl)
154 static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
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);
164 /* Switch to FIPS cipher implementation if possible */
165 if (cipher != NULL) {
166 const EVP_CIPHER *fcipher;
167 fcipher = FIPS_get_cipherbynid(EVP_CIPHER_nid(cipher));
172 * Other algorithm blocking will be done in FIPS_cmac_init, via
175 if (!impl && !ctx->cctx.engine)
176 return FIPS_cmac_init(ctx, key, keylen, cipher, NULL);
179 /* All zeros means restart */
180 if (!key && !cipher && !impl && keylen == 0) {
181 /* Not initialised */
182 if (ctx->nlast_block == -1)
184 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
186 memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(&ctx->cctx));
187 ctx->nlast_block = 0;
190 /* Initialiase context */
191 if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
193 /* Non-NULL key means initialisation complete */
196 if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
198 if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
200 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
202 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
203 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
205 make_kn(ctx->k1, ctx->tbl, bl);
206 make_kn(ctx->k2, ctx->k1, bl);
207 OPENSSL_cleanse(ctx->tbl, bl);
208 /* Reset context again ready for first data block */
209 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
211 /* Zero tbl so resume works */
212 memset(ctx->tbl, 0, bl);
213 ctx->nlast_block = 0;
218 int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
220 const unsigned char *data = in;
223 if (FIPS_mode() && !ctx->cctx.engine)
224 return FIPS_cmac_update(ctx, in, dlen);
226 if (ctx->nlast_block == -1)
230 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
231 /* Copy into partial block if we need to */
232 if (ctx->nlast_block > 0) {
234 nleft = bl - ctx->nlast_block;
237 memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
239 ctx->nlast_block += nleft;
240 /* If no more to process return */
244 /* Else not final block so encrypt it */
245 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block, bl))
248 /* Encrypt all but one of the complete blocks left */
250 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
255 /* Copy any data left to last block buffer */
256 memcpy(ctx->last_block, data, dlen);
257 ctx->nlast_block = dlen;
262 int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
266 if (FIPS_mode() && !ctx->cctx.engine)
267 return FIPS_cmac_final(ctx, out, poutlen);
269 if (ctx->nlast_block == -1)
271 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
272 *poutlen = (size_t)bl;
275 lb = ctx->nlast_block;
276 /* Is last block complete? */
278 for (i = 0; i < bl; i++)
279 out[i] = ctx->last_block[i] ^ ctx->k1[i];
281 ctx->last_block[lb] = 0x80;
283 memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
284 for (i = 0; i < bl; i++)
285 out[i] = ctx->last_block[i] ^ ctx->k2[i];
287 if (!EVP_Cipher(&ctx->cctx, out, out, bl)) {
288 OPENSSL_cleanse(out, bl);
294 int CMAC_resume(CMAC_CTX *ctx)
296 if (ctx->nlast_block == -1)
299 * The buffer "tbl" containes the last fully encrypted block which is the
300 * last IV (or all zeroes if no last encrypted block). The last block has
301 * not been modified since CMAC_final(). So reinitliasing using the last
302 * decrypted block will allow CMAC to continue after calling
305 return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);