crypto/openssl/crypto/cmac/cmac.c

   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 static void make_kn(unsigned char *k1, unsigned char *l, int bl)
  82 {
  83     int i;
  84     /* Shift block to left, including carry */
  85     for (i = 0; i < bl; i++) {
  86         k1[i] = l[i] << 1;
  87         if (i < bl - 1 && l[i + 1] & 0x80)
  88             k1[i] |= 1;
  89     }
  90     /* If MSB set fixup with R */
  91     if (l[0] & 0x80)
  92         k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
  93 }
  94
  95 CMAC_CTX *CMAC_CTX_new(void)
  96 {
  97     CMAC_CTX *ctx;
  98     ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
  99     if (!ctx)
 100         return NULL;
 101     EVP_CIPHER_CTX_init(&ctx->cctx);
 102     ctx->nlast_block = -1;
 103     return ctx;
 104 }
 105
 106 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     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;
 120 }
 121
 122 EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
 123 {
 124     return &ctx->cctx;
 125 }
 126
 127 void CMAC_CTX_free(CMAC_CTX *ctx)
 128 {
 129     if (!ctx)
 130         return;
 131     CMAC_CTX_cleanup(ctx);
 132     OPENSSL_free(ctx);
 133 }
 134
 135 int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
 136 {
 137     int bl;
 138     if (in->nlast_block == -1)
 139         return 0;
 140     if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
 141         return 0;
 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;
 148     return 1;
 149 }
 150
 151 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         /* 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));
 168             if (fcipher != NULL)
 169                 cipher = fcipher;
 170         }
 171         /*
 172          * Other algorithm blocking will be done in FIPS_cmac_init, via
 173          * FIPS_cipherinit().
 174          */
 175         if (!impl && !ctx->cctx.engine)
 176             return FIPS_cmac_init(ctx, key, keylen, cipher, NULL);
 177     }
 178 #endif
 179     /* All zeros means restart */
 180     if (!key && !cipher && !impl && keylen == 0) {
 181         /* Not initialised */
 182         if (ctx->nlast_block == -1)
 183             return 0;
 184         if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
 185             return 0;
 186         memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(&ctx->cctx));
 187         ctx->nlast_block = 0;
 188         return 1;
 189     }
 190     /* Initialiase context */
 191     if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
 192         return 0;
 193     /* Non-NULL key means initialisation complete */
 194     if (key) {
 195         int bl;
 196         if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
 197             return 0;
 198         if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
 199             return 0;
 200         if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
 201             return 0;
 202         bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
 203         if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
 204             return 0;
 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))
 210             return 0;
 211         /* Zero tbl so resume works */
 212         memset(ctx->tbl, 0, bl);
 213         ctx->nlast_block = 0;
 214     }
 215     return 1;
 216 }
 217
 218 int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
 219 {
 220     const unsigned char *data = in;
 221     size_t bl;
 222 #ifdef OPENSSL_FIPS
 223     if (FIPS_mode() && !ctx->cctx.engine)
 224         return FIPS_cmac_update(ctx, in, dlen);
 225 #endif
 226     if (ctx->nlast_block == -1)
 227         return 0;
 228     if (dlen == 0)
 229         return 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) {
 233         size_t nleft;
 234         nleft = bl - ctx->nlast_block;
 235         if (dlen < nleft)
 236             nleft = dlen;
 237         memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
 238         dlen -= nleft;
 239         ctx->nlast_block += nleft;
 240         /* If no more to process return */
 241         if (dlen == 0)
 242             return 1;
 243         data += nleft;
 244         /* Else not final block so encrypt it */
 245         if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block, bl))
 246             return 0;
 247     }
 248     /* Encrypt all but one of the complete blocks left */
 249     while (dlen > bl) {
 250         if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
 251             return 0;
 252         dlen -= bl;
 253         data += bl;
 254     }
 255     /* Copy any data left to last block buffer */
 256     memcpy(ctx->last_block, data, dlen);
 257     ctx->nlast_block = dlen;
 258     return 1;
 259
 260 }
 261
 262 int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
 263 {
 264     int i, bl, lb;
 265 #ifdef OPENSSL_FIPS
 266     if (FIPS_mode() && !ctx->cctx.engine)
 267         return FIPS_cmac_final(ctx, out, poutlen);
 268 #endif
 269     if (ctx->nlast_block == -1)
 270         return 0;
 271     bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
 272     *poutlen = (size_t)bl;
 273     if (!out)
 274         return 1;
 275     lb = ctx->nlast_block;
 276     /* Is last block complete? */
 277     if (lb == bl) {
 278         for (i = 0; i < bl; i++)
 279             out[i] = ctx->last_block[i] ^ ctx->k1[i];
 280     } else {
 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         OPENSSL_cleanse(out, bl);
 289         return 0;
 290     }
 291     return 1;
 292 }
 293
 294 int CMAC_resume(CMAC_CTX *ctx)
 295 {
 296     if (ctx->nlast_block == -1)
 297         return 0;
 298     /*
 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
 303      * CMAC_Final().
 304      */
 305     return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);
 306 }