Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 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) |
| 125 | { |
| 126 | BN_zero(rnd); |
| 127 | return 1; |
| 128 | } |
| 129 | |
| 130 | bytes=(bits+7)/8; |
| 131 | bit=(bits-1)%8; |
| 132 | mask=0xff<<(bit+1); |
| 133 | |
| 134 | buf=(unsigned char *)OPENSSL_malloc(bytes); |
| 135 | if (buf == NULL) |
| 136 | { |
| 137 | BNerr(BN_F_BNRAND,ERR_R_MALLOC_FAILURE); |
| 138 | goto err; |
| 139 | } |
| 140 | |
| 141 | /* make a random number and set the top and bottom bits */ |
| 142 | time(&tim); |
| 143 | RAND_add(&tim,sizeof(tim),0.0); |
| 144 | |
| 145 | if (pseudorand) |
| 146 | { |
| 147 | if (RAND_pseudo_bytes(buf, bytes) == -1) |
| 148 | goto err; |
| 149 | } |
| 150 | else |
| 151 | { |
| 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 |
| 160 | library bugs */ |
| 161 | int i; |
| 162 | unsigned char c; |
| 163 | |
| 164 | for (i = 0; i < bytes; i++) |
| 165 | { |
| 166 | RAND_pseudo_bytes(&c, 1); |
| 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 != -1) |
| 178 | { |
| 179 | if (top) |
| 180 | { |
| 181 | if (bit == 0) |
| 182 | { |
| 183 | buf[0]=1; |
| 184 | buf[1]|=0x80; |
| 185 | } |
| 186 | else |
| 187 | { |
| 188 | buf[0]|=(3<<(bit-1)); |
| 189 | } |
| 190 | } |
| 191 | else |
| 192 | { |
| 193 | buf[0]|=(1<<bit); |
| 194 | } |
| 195 | } |
| 196 | buf[0] &= ~mask; |
| 197 | if (bottom) /* set bottom bit if requested */ |
| 198 | buf[bytes-1]|=1; |
| 199 | if (!BN_bin2bn(buf,bytes,rnd)) goto err; |
| 200 | ret=1; |
| 201 | err: |
| 202 | if (buf != NULL) |
| 203 | { |
| 204 | OPENSSL_cleanse(buf,bytes); |
| 205 | OPENSSL_free(buf); |
| 206 | } |
| 207 | bn_check_top(rnd); |
| 208 | return(ret); |
| 209 | } |
| 210 | |
| 211 | int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) |
| 212 | { |
| 213 | return bnrand(0, rnd, bits, top, bottom); |
| 214 | } |
| 215 | |
| 216 | int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) |
| 217 | { |
| 218 | return bnrand(1, rnd, bits, top, bottom); |
| 219 | } |
| 220 | |
| 221 | #if 1 |
| 222 | int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) |
| 223 | { |
| 224 | return bnrand(2, rnd, bits, top, bottom); |
| 225 | } |
| 226 | #endif |
| 227 | |
| 228 | |
| 229 | /* random number r: 0 <= r < range */ |
| 230 | static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) |
| 231 | { |
| 232 | int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand; |
| 233 | int n; |
| 234 | int count = 100; |
| 235 | |
| 236 | if (range->neg || BN_is_zero(range)) |
| 237 | { |
| 238 | BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); |
| 239 | return 0; |
| 240 | } |
| 241 | |
| 242 | n = BN_num_bits(range); /* n > 0 */ |
| 243 | |
| 244 | /* BN_is_bit_set(range, n - 1) always holds */ |
| 245 | |
| 246 | if (n == 1) |
| 247 | BN_zero(r); |
| 248 | else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) |
| 249 | { |
| 250 | /* range = 100..._2, |
| 251 | * so 3*range (= 11..._2) is exactly one bit longer than range */ |
| 252 | do |
| 253 | { |
| 254 | if (!bn_rand(r, n + 1, -1, 0)) return 0; |
| 255 | /* If r < 3*range, use r := r MOD range |
| 256 | * (which is either r, r - range, or r - 2*range). |
| 257 | * Otherwise, iterate once more. |
| 258 | * Since 3*range = 11..._2, each iteration succeeds with |
| 259 | * probability >= .75. */ |
| 260 | if (BN_cmp(r ,range) >= 0) |
| 261 | { |
| 262 | if (!BN_sub(r, r, range)) return 0; |
| 263 | if (BN_cmp(r, range) >= 0) |
| 264 | if (!BN_sub(r, r, range)) return 0; |
| 265 | } |
| 266 | |
| 267 | if (!--count) |
| 268 | { |
| 269 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); |
| 270 | return 0; |
| 271 | } |
| 272 | |
| 273 | } |
| 274 | while (BN_cmp(r, range) >= 0); |
| 275 | } |
| 276 | else |
| 277 | { |
| 278 | do |
| 279 | { |
| 280 | /* range = 11..._2 or range = 101..._2 */ |
| 281 | if (!bn_rand(r, n, -1, 0)) return 0; |
| 282 | |
| 283 | if (!--count) |
| 284 | { |
| 285 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); |
| 286 | return 0; |
| 287 | } |
| 288 | } |
| 289 | while (BN_cmp(r, range) >= 0); |
| 290 | } |
| 291 | |
| 292 | bn_check_top(r); |
| 293 | return 1; |
| 294 | } |
| 295 | |
| 296 | |
| 297 | int BN_rand_range(BIGNUM *r, const BIGNUM *range) |
| 298 | { |
| 299 | return bn_rand_range(0, r, range); |
| 300 | } |
| 301 | |
| 302 | int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) |
| 303 | { |
| 304 | return bn_rand_range(1, r, range); |
| 305 | } |