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 } 309