1 /* crypto/cmac/cmac.c */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
5 /* ====================================================================
6 * Copyright (c) 2010 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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 * ====================================================================
58 #include <openssl/cmac.h>
62 /* Cipher context to use */
65 unsigned char k1[EVP_MAX_BLOCK_LENGTH];
66 unsigned char k2[EVP_MAX_BLOCK_LENGTH];
68 unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
69 /* Last (possibly partial) block */
70 unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
71 /* Number of bytes in last block: -1 means context not initialised */
76 /* Make temporary keys K1 and K2 */
78 static void make_kn(unsigned char *k1, unsigned char *l, int bl)
81 /* Shift block to left, including carry */
82 for (i = 0; i < bl; i++)
85 if (i < bl - 1 && l[i + 1] & 0x80)
88 /* If MSB set fixup with R */
90 k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
93 CMAC_CTX *CMAC_CTX_new(void)
96 ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
99 EVP_CIPHER_CTX_init(&ctx->cctx);
100 ctx->nlast_block = -1;
104 void CMAC_CTX_cleanup(CMAC_CTX *ctx)
106 EVP_CIPHER_CTX_cleanup(&ctx->cctx);
107 OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
108 OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
109 OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
110 OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
111 ctx->nlast_block = -1;
114 EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
119 void CMAC_CTX_free(CMAC_CTX *ctx)
121 CMAC_CTX_cleanup(ctx);
125 int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
128 if (in->nlast_block == -1)
130 if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
132 bl = EVP_CIPHER_CTX_block_size(&in->cctx);
133 memcpy(out->k1, in->k1, bl);
134 memcpy(out->k2, in->k2, bl);
135 memcpy(out->tbl, in->tbl, bl);
136 memcpy(out->last_block, in->last_block, bl);
137 out->nlast_block = in->nlast_block;
141 int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
142 const EVP_CIPHER *cipher, ENGINE *impl)
144 static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
145 /* All zeros means restart */
146 if (!key && !cipher && !impl && keylen == 0)
148 /* Not initialised */
149 if (ctx->nlast_block == -1)
151 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
155 /* Initialiase context */
156 if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
158 /* Non-NULL key means initialisation complete */
162 if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
164 if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
166 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
168 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
169 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
171 make_kn(ctx->k1, ctx->tbl, bl);
172 make_kn(ctx->k2, ctx->k1, bl);
173 OPENSSL_cleanse(ctx->tbl, bl);
174 /* Reset context again ready for first data block */
175 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
177 /* Zero tbl so resume works */
178 memset(ctx->tbl, 0, bl);
179 ctx->nlast_block = 0;
184 int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
186 const unsigned char *data = in;
188 if (ctx->nlast_block == -1)
192 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
193 /* Copy into partial block if we need to */
194 if (ctx->nlast_block > 0)
197 nleft = bl - ctx->nlast_block;
200 memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
202 ctx->nlast_block += nleft;
203 /* If no more to process return */
207 /* Else not final block so encrypt it */
208 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block,bl))
211 /* Encrypt all but one of the complete blocks left */
214 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
219 /* Copy any data left to last block buffer */
220 memcpy(ctx->last_block, data, dlen);
221 ctx->nlast_block = dlen;
226 int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
229 if (ctx->nlast_block == -1)
231 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
232 *poutlen = (size_t)bl;
235 lb = ctx->nlast_block;
236 /* Is last block complete? */
239 for (i = 0; i < bl; i++)
240 out[i] = ctx->last_block[i] ^ ctx->k1[i];
244 ctx->last_block[lb] = 0x80;
246 memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
247 for (i = 0; i < bl; i++)
248 out[i] = ctx->last_block[i] ^ ctx->k2[i];
250 if (!EVP_Cipher(&ctx->cctx, out, out, bl))
252 OPENSSL_cleanse(out, bl);
258 int CMAC_resume(CMAC_CTX *ctx)
260 if (ctx->nlast_block == -1)
262 /* The buffer "tbl" containes the last fully encrypted block
263 * which is the last IV (or all zeroes if no last encrypted block).
264 * The last block has not been modified since CMAC_final().
265 * So reinitliasing using the last decrypted block will allow
266 * CMAC to continue after calling CMAC_Final().
268 return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);