release/src/router/openssl/crypto/bn/bn_rand.c

   1 /* crypto/bn/bn_rand.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58 /* ====================================================================
  59  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
  60  *
  61  * Redistribution and use in source and binary forms, with or without
  62  * modification, are permitted provided that the following conditions
  63  * are met:
  64  *
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  *
  68  * 2. Redistributions in binary form must reproduce the above copyright
  69  *    notice, this list of conditions and the following disclaimer in
  70  *    the documentation and/or other materials provided with the
  71  *    distribution.
  72  *
  73  * 3. All advertising materials mentioning features or use of this
  74  *    software must display the following acknowledgment:
  75  *    "This product includes software developed by the OpenSSL Project
  76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  77  *
  78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  79  *    endorse or promote products derived from this software without
  80  *    prior written permission. For written permission, please contact
  81  *    openssl-core@openssl.org.
  82  *
  83  * 5. Products derived from this software may not be called "OpenSSL"
  84  *    nor may "OpenSSL" appear in their names without prior written
  85  *    permission of the OpenSSL Project.
  86  *
  87  * 6. Redistributions of any form whatsoever must retain the following
  88  *    acknowledgment:
  89  *    "This product includes software developed by the OpenSSL Project
  90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  91  *
  92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 103  * OF THE POSSIBILITY OF SUCH DAMAGE.
 104  * ====================================================================
 105  *
 106  * This product includes cryptographic software written by Eric Young
 107  * (eay@cryptsoft.com).  This product includes software written by Tim
 108  * Hudson (tjh@cryptsoft.com).
 109  *
 110  */
 111
 112 #include <stdio.h>
 113 #include <time.h>
 114 #include "cryptlib.h"
 115 #include "bn_lcl.h"
 116 #include <openssl/rand.h>
 117
 118 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
 119 {
 120     unsigned char *buf = NULL;
 121     int ret = 0, bit, bytes, mask;
 122     time_t tim;
 123
 124     if (bits < 0 || (bits == 1 && top > 0)) {
 125         BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
 126         return 0;
 127     }
 128
 129     if (bits == 0) {
 130         BN_zero(rnd);
 131         return 1;
 132     }
 133
 134     bytes = (bits + 7) / 8;
 135     bit = (bits - 1) % 8;
 136     mask = 0xff << (bit + 1);
 137
 138     buf = (unsigned char *)OPENSSL_malloc(bytes);
 139     if (buf == NULL) {
 140         BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE);
 141         goto err;
 142     }
 143
 144     /* make a random number and set the top and bottom bits */
 145     time(&tim);
 146     RAND_add(&tim, sizeof(tim), 0.0);
 147
 148     if (pseudorand) {
 149         if (RAND_pseudo_bytes(buf, bytes) == -1)
 150             goto err;
 151     } else {
 152         if (RAND_bytes(buf, bytes) <= 0)
 153             goto err;
 154     }
 155
 156 #if 1
 157     if (pseudorand == 2) {
 158         /*
 159          * generate patterns that are more likely to trigger BN library bugs
 160          */
 161         int i;
 162         unsigned char c;
 163
 164         for (i = 0; i < bytes; i++) {
 165             if (RAND_pseudo_bytes(&c, 1) < 0)
 166                 goto err;
 167             if (c >= 128 && i > 0)
 168                 buf[i] = buf[i - 1];
 169             else if (c < 42)
 170                 buf[i] = 0;
 171             else if (c < 84)
 172                 buf[i] = 255;
 173         }
 174     }
 175 #endif
 176
 177     if (top >= 0) {
 178         if (top) {
 179             if (bit == 0) {
 180                 buf[0] = 1;
 181                 buf[1] |= 0x80;
 182             } else {
 183                 buf[0] |= (3 << (bit - 1));
 184             }
 185         } else {
 186             buf[0] |= (1 << bit);
 187         }
 188     }
 189     buf[0] &= ~mask;
 190     if (bottom)                 /* set bottom bit if requested */
 191         buf[bytes - 1] |= 1;
 192     if (!BN_bin2bn(buf, bytes, rnd))
 193         goto err;
 194     ret = 1;
 195  err:
 196     if (buf != NULL) {
 197         OPENSSL_cleanse(buf, bytes);
 198         OPENSSL_free(buf);
 199     }
 200     bn_check_top(rnd);
 201     return (ret);
 202 }
 203
 204 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
 205 {
 206     return bnrand(0, rnd, bits, top, bottom);
 207 }
 208
 209 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
 210 {
 211     return bnrand(1, rnd, bits, top, bottom);
 212 }
 213
 214 #if 1
 215 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
 216 {
 217     return bnrand(2, rnd, bits, top, bottom);
 218 }
 219 #endif
 220
 221 /* random number r:  0 <= r < range */
 222 static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range)
 223 {
 224     int (*bn_rand) (BIGNUM *, int, int, int) =
 225         pseudo ? BN_pseudo_rand : BN_rand;
 226     int n;
 227     int count = 100;
 228
 229     if (range->neg || BN_is_zero(range)) {
 230         BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
 231         return 0;
 232     }
 233
 234     n = BN_num_bits(range);     /* n > 0 */
 235
 236     /* BN_is_bit_set(range, n - 1) always holds */
 237
 238     if (n == 1)
 239         BN_zero(r);
 240     else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
 241         /*
 242          * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer
 243          * than range
 244          */
 245         do {
 246             if (!bn_rand(r, n + 1, -1, 0))
 247                 return 0;
 248             /*
 249              * If r < 3*range, use r := r MOD range (which is either r, r -
 250              * range, or r - 2*range). Otherwise, iterate once more. Since
 251              * 3*range = 11..._2, each iteration succeeds with probability >=
 252              * .75.
 253              */
 254             if (BN_cmp(r, range) >= 0) {
 255                 if (!BN_sub(r, r, range))
 256                     return 0;
 257                 if (BN_cmp(r, range) >= 0)
 258                     if (!BN_sub(r, r, range))
 259                         return 0;
 260             }
 261
 262             if (!--count) {
 263                 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
 264                 return 0;
 265             }
 266
 267         }
 268         while (BN_cmp(r, range) >= 0);
 269     } else {
 270         do {
 271             /* range = 11..._2  or  range = 101..._2 */
 272             if (!bn_rand(r, n, -1, 0))
 273                 return 0;
 274
 275             if (!--count) {
 276                 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
 277                 return 0;
 278             }
 279         }
 280         while (BN_cmp(r, range) >= 0);
 281     }
 282
 283     bn_check_top(r);
 284     return 1;
 285 }
 286
 287 int BN_rand_range(BIGNUM *r, const BIGNUM *range)
 288 {
 289     return bn_rand_range(0, r, range);
 290 }
 291
 292 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range)
 293 {
 294     return bn_rand_range(1, r, range);
 295 }