fips/rand/fips_drbg_ctr.c

   1 /* fips/rand/fips_drbg_ctr.c */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 2011 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 <stdlib.h>
  55 #include <string.h>
  56 #include <openssl/crypto.h>
  57 #include <openssl/fips.h>
  58 #include <openssl/fips_rand.h>
  59 #include "fips_rand_lcl.h"
  60
  61 static void inc_128(DRBG_CTR_CTX *cctx)
  62         {
  63         int i;
  64         unsigned char c;
  65         unsigned char *p = cctx->V + 15;
  66         for (i = 0; i < 16; i++)
  67                 {
  68                 c = *p;
  69                 c++;
  70                 *p = c;
  71                 if (c)
  72                         return;
  73                 p--;
  74                 }
  75         }
  76
  77 static void ctr_XOR(DRBG_CTR_CTX *cctx, const unsigned char *in, size_t inlen)
  78         {
  79         size_t i, n;
  80         /* Any zero padding will have no effect on the result as we
  81          * are XORing. So just process however much input we have.
  82          */
  83
  84         if (!in || !inlen)
  85                 return;
  86
  87         if (inlen < cctx->keylen)
  88                 n = inlen;
  89         else
  90                 n = cctx->keylen;
  91
  92         for (i = 0; i < n; i++)
  93                 cctx->K[i] ^= in[i];
  94         if (inlen <= cctx->keylen)
  95                 return;
  96
  97         n = inlen - cctx->keylen;
  98         /* Should never happen */
  99         if (n > 16)
 100                 n = 16;
 101         for (i = 0; i < 16; i++)
 102                 cctx->V[i] ^= in[i + cctx->keylen];
 103         }
 104
 105 /* Process a complete block using BCC algorithm of SPP 800-90 10.4.3 */
 106
 107 static void ctr_BCC_block(DRBG_CTR_CTX *cctx, unsigned char *out,
 108                                 const unsigned char *in)
 109         {
 110         int i;
 111         for (i = 0; i < 16; i++)
 112                 out[i] ^= in[i];
 113         AES_encrypt(out, out, &cctx->df_ks);
 114 #if 0
 115 fprintf(stderr, "BCC in+out\n");
 116 BIO_dump_fp(stderr, in, 16);
 117 BIO_dump_fp(stderr, out, 16);
 118 #endif
 119         }
 120
 121 /* Handle several BCC operations for as much data as we need for K and X */
 122 static void ctr_BCC_blocks(DRBG_CTR_CTX *cctx, const unsigned char *in)
 123         {
 124         ctr_BCC_block(cctx, cctx->KX, in);
 125         ctr_BCC_block(cctx, cctx->KX + 16, in);
 126         if (cctx->keylen != 16)
 127                 ctr_BCC_block(cctx, cctx->KX + 32, in);
 128         }
 129 /* Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:
 130  * see 10.4.2 stage 7.
 131  */
 132 static void ctr_BCC_init(DRBG_CTR_CTX *cctx)
 133         {
 134         memset(cctx->KX, 0, 48);
 135         memset(cctx->bltmp, 0, 16);
 136         ctr_BCC_block(cctx, cctx->KX, cctx->bltmp);
 137         cctx->bltmp[3] = 1;
 138         ctr_BCC_block(cctx, cctx->KX + 16, cctx->bltmp);
 139         if (cctx->keylen != 16)
 140                 {
 141                 cctx->bltmp[3] = 2;
 142                 ctr_BCC_block(cctx, cctx->KX + 32, cctx->bltmp);
 143                 }
 144         }
 145
 146 /* Process several blocks into BCC algorithm, some possibly partial */
 147 static void ctr_BCC_update(DRBG_CTR_CTX *cctx,
 148                                 const unsigned char *in, size_t inlen)
 149         {
 150         if (!in || !inlen)
 151                 return;
 152         /* If we have partial block handle it first */
 153         if (cctx->bltmp_pos)
 154                 {
 155                 size_t left = 16 - cctx->bltmp_pos;
 156                 /* If we now have a complete block process it */
 157                 if (inlen >= left)
 158                         {
 159                         memcpy(cctx->bltmp + cctx->bltmp_pos, in, left);
 160                         ctr_BCC_blocks(cctx, cctx->bltmp);
 161                         cctx->bltmp_pos = 0;
 162                         inlen -= left;
 163                         in += left;
 164                         }
 165                 }
 166         /* Process zero or more complete blocks */
 167         while (inlen >= 16)
 168                 {
 169                 ctr_BCC_blocks(cctx, in);
 170                 in += 16;
 171                 inlen -= 16;
 172                 }
 173         /* Copy any remaining partial block to the temporary buffer */
 174         if (inlen > 0)
 175                 {
 176                 memcpy(cctx->bltmp + cctx->bltmp_pos, in, inlen);
 177                 cctx->bltmp_pos += inlen;
 178                 }
 179         }
 180
 181 static void ctr_BCC_final(DRBG_CTR_CTX *cctx)
 182         {
 183         if (cctx->bltmp_pos)
 184                 {
 185                 memset(cctx->bltmp + cctx->bltmp_pos, 0, 16 - cctx->bltmp_pos);
 186                 ctr_BCC_blocks(cctx, cctx->bltmp);
 187                 }
 188         }
 189
 190 static void ctr_df(DRBG_CTR_CTX *cctx,
 191                         const unsigned char *in1, size_t in1len,
 192                         const unsigned char *in2, size_t in2len,
 193                         const unsigned char *in3, size_t in3len)
 194         {
 195         size_t inlen;
 196         unsigned char *p = cctx->bltmp;
 197         static unsigned char c80 = 0x80;
 198
 199         ctr_BCC_init(cctx);
 200         if (!in1)
 201                 in1len = 0;
 202         if (!in2)
 203                 in2len = 0;
 204         if (!in3)
 205                 in3len = 0;
 206         inlen = in1len + in2len + in3len;
 207         /* Initialise L||N in temporary block */
 208         *p++ = (inlen >> 24) & 0xff;
 209         *p++ = (inlen >> 16) & 0xff;
 210         *p++ = (inlen >> 8) & 0xff;
 211         *p++ = inlen & 0xff;
 212         /* NB keylen is at most 32 bytes */
 213         *p++ = 0;
 214         *p++ = 0;
 215         *p++ = 0;
 216         *p = (unsigned char)((cctx->keylen + 16) & 0xff);
 217         cctx->bltmp_pos = 8;
 218         ctr_BCC_update(cctx, in1, in1len);
 219         ctr_BCC_update(cctx, in2, in2len);
 220         ctr_BCC_update(cctx, in3, in3len);
 221         ctr_BCC_update(cctx, &c80, 1);
 222         ctr_BCC_final(cctx);
 223         /* Set up key K */
 224         AES_set_encrypt_key(cctx->KX, cctx->keylen * 8, &cctx->df_kxks);
 225         /* X follows key K */
 226         AES_encrypt(cctx->KX + cctx->keylen, cctx->KX, &cctx->df_kxks);
 227         AES_encrypt(cctx->KX, cctx->KX + 16, &cctx->df_kxks);
 228         if (cctx->keylen != 16)
 229                 AES_encrypt(cctx->KX + 16, cctx->KX + 32, &cctx->df_kxks);
 230 #if 0
 231 fprintf(stderr, "Output of ctr_df:\n");
 232 BIO_dump_fp(stderr, cctx->KX, cctx->keylen + 16);
 233 #endif
 234         }
 235
 236 /* NB the no-df  Update in SP800-90 specifies a constant input length
 237  * of seedlen, however other uses of this algorithm pad the input with
 238  * zeroes if necessary and have up to two parameters XORed together,
 239  * handle both cases in this function instead.
 240  */
 241
 242 static void ctr_Update(DRBG_CTX *dctx,
 243                 const unsigned char *in1, size_t in1len,
 244                 const unsigned char *in2, size_t in2len,
 245                 const unsigned char *nonce, size_t noncelen)
 246         {
 247         DRBG_CTR_CTX *cctx = &dctx->d.ctr;
 248         /* ks is already setup for correct key */
 249         inc_128(cctx);
 250         AES_encrypt(cctx->V, cctx->K, &cctx->ks);
 251         /* If keylen longer than 128 bits need extra encrypt */
 252         if (cctx->keylen != 16)
 253                 {
 254                 inc_128(cctx);
 255                 AES_encrypt(cctx->V, cctx->K + 16, &cctx->ks);
 256                 }
 257         inc_128(cctx);
 258         AES_encrypt(cctx->V, cctx->V, &cctx->ks);
 259         /* If 192 bit key part of V is on end of K */
 260         if (cctx->keylen == 24)
 261                 {
 262                 memcpy(cctx->V + 8, cctx->V, 8);
 263                 memcpy(cctx->V, cctx->K + 24, 8);
 264                 }
 265
 266         if (dctx->xflags & DRBG_FLAG_CTR_USE_DF)
 267                 {
 268                 /* If no input reuse existing derived value */
 269                 if (in1 || nonce || in2)
 270                         ctr_df(cctx, in1, in1len, nonce, noncelen, in2, in2len);
 271                 /* If this a reuse input in1len != 0 */
 272                 if (in1len)
 273                         ctr_XOR(cctx, cctx->KX, dctx->seedlen);
 274                 }
 275         else
 276                 {
 277                 ctr_XOR(cctx, in1, in1len);
 278                 ctr_XOR(cctx, in2, in2len);
 279                 }
 280
 281         AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
 282 #if 0
 283 fprintf(stderr, "K+V after update is:\n");
 284 BIO_dump_fp(stderr, cctx->K, cctx->keylen);
 285 BIO_dump_fp(stderr, cctx->V, 16);
 286 #endif
 287         }
 288
 289 static int drbg_ctr_instantiate(DRBG_CTX *dctx,
 290                         const unsigned char *ent, size_t entlen,
 291                         const unsigned char *nonce, size_t noncelen,
 292                         const unsigned char *pers, size_t perslen)
 293         {
 294         DRBG_CTR_CTX *cctx = &dctx->d.ctr;
 295         memset(cctx->K, 0, sizeof(cctx->K));
 296         memset(cctx->V, 0, sizeof(cctx->V));
 297         AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
 298         ctr_Update(dctx, ent, entlen, pers, perslen, nonce, noncelen);
 299         return 1;
 300         }
 301
 302 static int drbg_ctr_reseed(DRBG_CTX *dctx,
 303                         const unsigned char *ent, size_t entlen,
 304                         const unsigned char *adin, size_t adinlen)
 305         {
 306         ctr_Update(dctx, ent, entlen, adin, adinlen, NULL, 0);
 307         return 1;
 308         }
 309
 310 static int drbg_ctr_generate(DRBG_CTX *dctx,
 311                         unsigned char *out, size_t outlen,
 312                         const unsigned char *adin, size_t adinlen)
 313         {
 314         DRBG_CTR_CTX *cctx = &dctx->d.ctr;
 315         if (adin && adinlen)
 316                 {
 317                 ctr_Update(dctx, adin, adinlen, NULL, 0, NULL, 0);
 318                 /* This means we reuse derived value */
 319                 if (dctx->xflags & DRBG_FLAG_CTR_USE_DF)
 320                         {
 321                         adin = NULL;
 322                         adinlen = 1;
 323                         }
 324                 }
 325         else
 326                 adinlen = 0;
 327
 328         for (;;)
 329                 {
 330                 inc_128(cctx);
 331                 if (!(dctx->xflags & DRBG_FLAG_TEST) && !dctx->lb_valid)
 332                         {
 333                         AES_encrypt(cctx->V, dctx->lb, &cctx->ks);
 334                         dctx->lb_valid = 1;
 335                         continue;
 336                         }
 337                 if (outlen < 16)
 338                         {
 339                         /* Use K as temp space as it will be updated */
 340                         AES_encrypt(cctx->V, cctx->K, &cctx->ks);
 341                         if (!fips_drbg_cprng_test(dctx, cctx->K))
 342                                 return 0;
 343                         memcpy(out, cctx->K, outlen);
 344                         break;
 345                         }
 346                 AES_encrypt(cctx->V, out, &cctx->ks);
 347                 if (!fips_drbg_cprng_test(dctx, out))
 348                         return 0;
 349                 out += 16;
 350                 outlen -= 16;
 351                 if (outlen == 0)
 352                         break;
 353                 }
 354
 355         ctr_Update(dctx, adin, adinlen, NULL, 0, NULL, 0);
 356
 357         return 1;
 358
 359         }
 360
 361 static int drbg_ctr_uninstantiate(DRBG_CTX *dctx)
 362         {
 363         memset(&dctx->d.ctr, 0, sizeof(DRBG_CTR_CTX));
 364         return 1;
 365         }
 366
 367 int fips_drbg_ctr_init(DRBG_CTX *dctx)
 368         {
 369         DRBG_CTR_CTX *cctx = &dctx->d.ctr;
 370
 371         size_t keylen;
 372
 373         switch (dctx->type)
 374                 {
 375                 case NID_aes_128_ctr:
 376                 keylen = 16;
 377                 break;
 378
 379                 case NID_aes_192_ctr:
 380                 keylen = 24;
 381                 break;
 382
 383                 case NID_aes_256_ctr:
 384                 keylen = 32;
 385                 break;
 386
 387                 default:
 388                 return -2;
 389                 }
 390
 391         dctx->instantiate = drbg_ctr_instantiate;
 392         dctx->reseed = drbg_ctr_reseed;
 393         dctx->generate = drbg_ctr_generate;
 394         dctx->uninstantiate = drbg_ctr_uninstantiate;
 395
 396         cctx->keylen = keylen;
 397         dctx->strength = keylen * 8;
 398         dctx->blocklength = 16;
 399         dctx->seedlen = keylen + 16;
 400
 401         if (dctx->xflags & DRBG_FLAG_CTR_USE_DF)
 402                 {
 403                 /* df initialisation */
 404                 static unsigned char df_key[32] =
 405                         {
 406                         0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
 407                         0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
 408                         0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
 409                         0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
 410                         };
 411                 /* Set key schedule for df_key */
 412                 AES_set_encrypt_key(df_key, dctx->strength, &cctx->df_ks);
 413
 414                 dctx->min_entropy = cctx->keylen;
 415                 dctx->max_entropy = DRBG_MAX_LENGTH;
 416                 dctx->min_nonce = dctx->min_entropy / 2;
 417                 dctx->max_nonce = DRBG_MAX_LENGTH;
 418                 dctx->max_pers = DRBG_MAX_LENGTH;
 419                 dctx->max_adin = DRBG_MAX_LENGTH;
 420                 }
 421         else
 422                 {
 423                 dctx->min_entropy = dctx->seedlen;
 424                 dctx->max_entropy = dctx->seedlen;
 425                 /* Nonce not used */
 426                 dctx->min_nonce = 0;
 427                 dctx->max_nonce = 0;
 428                 dctx->max_pers = dctx->seedlen;
 429                 dctx->max_adin = dctx->seedlen;
 430                 }
 431
 432         dctx->max_request = 1<<16;
 433         dctx->reseed_interval = 1<<24;
 434
 435         return 1;
 436         }