cmac.c revision 392aa7cc7d2b122614c5393c3e357da07fd07af3
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 64struct 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 82static 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 97CMAC_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 108void 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 125EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx) 126 { 127 return &ctx->cctx; 128 } 129 130void CMAC_CTX_free(CMAC_CTX *ctx) 131 { 132 CMAC_CTX_cleanup(ctx); 133 OPENSSL_free(ctx); 134 } 135 136int 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 152int 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 return 1; 183 } 184 /* Initialiase context */ 185 if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL)) 186 return 0; 187 /* Non-NULL key means initialisation complete */ 188 if (key) 189 { 190 int bl; 191 if (!EVP_CIPHER_CTX_cipher(&ctx->cctx)) 192 return 0; 193 if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen)) 194 return 0; 195 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv)) 196 return 0; 197 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx); 198 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl)) 199 return 0; 200 make_kn(ctx->k1, ctx->tbl, bl); 201 make_kn(ctx->k2, ctx->k1, bl); 202 OPENSSL_cleanse(ctx->tbl, bl); 203 /* Reset context again ready for first data block */ 204 if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv)) 205 return 0; 206 /* Zero tbl so resume works */ 207 memset(ctx->tbl, 0, bl); 208 ctx->nlast_block = 0; 209 } 210 return 1; 211 } 212 213int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen) 214 { 215 const unsigned char *data = in; 216 size_t bl; 217#ifdef OPENSSL_FIPS 218 if (FIPS_mode() && !ctx->cctx.engine) 219 return FIPS_cmac_update(ctx, in, dlen); 220#endif 221 if (ctx->nlast_block == -1) 222 return 0; 223 if (dlen == 0) 224 return 1; 225 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx); 226 /* Copy into partial block if we need to */ 227 if (ctx->nlast_block > 0) 228 { 229 size_t nleft; 230 nleft = bl - ctx->nlast_block; 231 if (dlen < nleft) 232 nleft = dlen; 233 memcpy(ctx->last_block + ctx->nlast_block, data, nleft); 234 dlen -= nleft; 235 ctx->nlast_block += nleft; 236 /* If no more to process return */ 237 if (dlen == 0) 238 return 1; 239 data += nleft; 240 /* Else not final block so encrypt it */ 241 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block,bl)) 242 return 0; 243 } 244 /* Encrypt all but one of the complete blocks left */ 245 while(dlen > bl) 246 { 247 if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl)) 248 return 0; 249 dlen -= bl; 250 data += bl; 251 } 252 /* Copy any data left to last block buffer */ 253 memcpy(ctx->last_block, data, dlen); 254 ctx->nlast_block = dlen; 255 return 1; 256 257 } 258 259int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen) 260 { 261 int i, bl, lb; 262#ifdef OPENSSL_FIPS 263 if (FIPS_mode() && !ctx->cctx.engine) 264 return FIPS_cmac_final(ctx, out, poutlen); 265#endif 266 if (ctx->nlast_block == -1) 267 return 0; 268 bl = EVP_CIPHER_CTX_block_size(&ctx->cctx); 269 *poutlen = (size_t)bl; 270 if (!out) 271 return 1; 272 lb = ctx->nlast_block; 273 /* Is last block complete? */ 274 if (lb == bl) 275 { 276 for (i = 0; i < bl; i++) 277 out[i] = ctx->last_block[i] ^ ctx->k1[i]; 278 } 279 else 280 { 281 ctx->last_block[lb] = 0x80; 282 if (bl - lb > 1) 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]; 286 } 287 if (!EVP_Cipher(&ctx->cctx, out, out, bl)) 288 { 289 OPENSSL_cleanse(out, bl); 290 return 0; 291 } 292 return 1; 293 } 294 295int CMAC_resume(CMAC_CTX *ctx) 296 { 297 if (ctx->nlast_block == -1) 298 return 0; 299 /* The buffer "tbl" containes the last fully encrypted block 300 * which is the last IV (or all zeroes if no last encrypted block). 301 * The last block has not been modified since CMAC_final(). 302 * So reinitliasing using the last decrypted block will allow 303 * CMAC to continue after calling CMAC_Final(). 304 */ 305 return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl); 306 } 307