1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] 56 */ 57 /* ==================================================================== 58 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. 59 * 60 * Redistribution and use in source and binary forms, with or without 61 * modification, are permitted provided that the following conditions 62 * are met: 63 * 64 * 1. Redistributions of source code must retain the above copyright 65 * notice, this list of conditions and the following disclaimer. 66 * 67 * 2. Redistributions in binary form must reproduce the above copyright 68 * notice, this list of conditions and the following disclaimer in 69 * the documentation and/or other materials provided with the 70 * distribution. 71 * 72 * 3. All advertising materials mentioning features or use of this 73 * software must display the following acknowledgment: 74 * "This product includes software developed by the OpenSSL Project 75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 76 * 77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 78 * endorse or promote products derived from this software without 79 * prior written permission. For written permission, please contact 80 * openssl-core (at) openssl.org. 81 * 82 * 5. Products derived from this software may not be called "OpenSSL" 83 * nor may "OpenSSL" appear in their names without prior written 84 * permission of the OpenSSL Project. 85 * 86 * 6. Redistributions of any form whatsoever must retain the following 87 * acknowledgment: 88 * "This product includes software developed by the OpenSSL Project 89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 90 * 91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 102 * OF THE POSSIBILITY OF SUCH DAMAGE. 103 * ==================================================================== 104 * 105 * This product includes cryptographic software written by Eric Young 106 * (eay (at) cryptsoft.com). This product includes software written by Tim 107 * Hudson (tjh (at) cryptsoft.com). */ 108 109 #include <openssl/bn.h> 110 111 #include <string.h> 112 113 #include <openssl/err.h> 114 #include <openssl/mem.h> 115 #include <openssl/rand.h> 116 #include <openssl/sha.h> 117 118 #include "../internal.h" 119 120 121 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { 122 uint8_t *buf = NULL; 123 int ret = 0, bit, bytes, mask; 124 125 if (rnd == NULL) { 126 return 0; 127 } 128 129 if (top != BN_RAND_TOP_ANY && top != BN_RAND_TOP_ONE && 130 top != BN_RAND_TOP_TWO) { 131 OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); 132 return 0; 133 } 134 135 if (bottom != BN_RAND_BOTTOM_ANY && bottom != BN_RAND_BOTTOM_ODD) { 136 OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); 137 return 0; 138 } 139 140 if (bits == 0) { 141 BN_zero(rnd); 142 return 1; 143 } 144 145 bytes = (bits + 7) / 8; 146 bit = (bits - 1) % 8; 147 mask = 0xff << (bit + 1); 148 149 buf = OPENSSL_malloc(bytes); 150 if (buf == NULL) { 151 OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); 152 goto err; 153 } 154 155 /* Make a random number and set the top and bottom bits. */ 156 if (!RAND_bytes(buf, bytes)) { 157 goto err; 158 } 159 160 if (top != BN_RAND_TOP_ANY) { 161 if (top == BN_RAND_TOP_TWO && bits > 1) { 162 if (bit == 0) { 163 buf[0] = 1; 164 buf[1] |= 0x80; 165 } else { 166 buf[0] |= (3 << (bit - 1)); 167 } 168 } else { 169 buf[0] |= (1 << bit); 170 } 171 } 172 173 buf[0] &= ~mask; 174 175 /* Set the bottom bit if requested, */ 176 if (bottom == BN_RAND_BOTTOM_ODD) { 177 buf[bytes - 1] |= 1; 178 } 179 180 if (!BN_bin2bn(buf, bytes, rnd)) { 181 goto err; 182 } 183 184 ret = 1; 185 186 err: 187 if (buf != NULL) { 188 OPENSSL_cleanse(buf, bytes); 189 OPENSSL_free(buf); 190 } 191 return (ret); 192 } 193 194 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { 195 return BN_rand(rnd, bits, top, bottom); 196 } 197 198 int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive, 199 const BIGNUM *max_exclusive) { 200 unsigned n; 201 unsigned count = 100; 202 203 if (BN_cmp_word(max_exclusive, min_inclusive) <= 0) { 204 OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE); 205 return 0; 206 } 207 208 n = BN_num_bits(max_exclusive); /* n > 0 */ 209 210 /* BN_is_bit_set(range, n - 1) always holds */ 211 if (n == 1) { 212 BN_zero(r); 213 return 1; 214 } 215 216 do { 217 if (!--count) { 218 OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS); 219 return 0; 220 } 221 222 if (!BN_is_bit_set(max_exclusive, n - 2) && 223 !BN_is_bit_set(max_exclusive, n - 3)) { 224 /* range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer 225 * than range. This is a common scenario when generating a random value 226 * modulo an RSA public modulus, e.g. for RSA base blinding. */ 227 if (!BN_rand(r, n + 1, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY)) { 228 return 0; 229 } 230 231 /* If r < 3*range, use r := r MOD range (which is either r, r - range, or 232 * r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each 233 * iteration succeeds with probability >= .75. */ 234 if (BN_cmp(r, max_exclusive) >= 0) { 235 if (!BN_sub(r, r, max_exclusive)) { 236 return 0; 237 } 238 if (BN_cmp(r, max_exclusive) >= 0) { 239 if (!BN_sub(r, r, max_exclusive)) { 240 return 0; 241 } 242 } 243 } 244 } else { 245 /* range = 11..._2 or range = 101..._2 */ 246 if (!BN_rand(r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY)) { 247 return 0; 248 } 249 } 250 } while (BN_cmp_word(r, min_inclusive) < 0 || 251 BN_cmp(r, max_exclusive) >= 0); 252 253 return 1; 254 } 255 256 int BN_rand_range(BIGNUM *r, const BIGNUM *range) { 257 return BN_rand_range_ex(r, 0, range); 258 } 259 260 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) { 261 return BN_rand_range(r, range); 262 } 263 264 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv, 265 const uint8_t *message, size_t message_len, 266 BN_CTX *ctx) { 267 SHA512_CTX sha; 268 /* We use 512 bits of random data per iteration to 269 * ensure that we have at least |range| bits of randomness. */ 270 uint8_t random_bytes[64]; 271 uint8_t digest[SHA512_DIGEST_LENGTH]; 272 size_t done, todo, attempt; 273 const unsigned num_k_bytes = BN_num_bytes(range); 274 const unsigned bits_to_mask = (8 - (BN_num_bits(range) % 8)) % 8; 275 uint8_t private_bytes[96]; 276 uint8_t *k_bytes = NULL; 277 int ret = 0; 278 279 if (out == NULL) { 280 return 0; 281 } 282 283 if (BN_is_zero(range)) { 284 OPENSSL_PUT_ERROR(BN, BN_R_DIV_BY_ZERO); 285 goto err; 286 } 287 288 k_bytes = OPENSSL_malloc(num_k_bytes); 289 if (!k_bytes) { 290 OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); 291 goto err; 292 } 293 294 /* We copy |priv| into a local buffer to avoid furthur exposing its 295 * length. */ 296 todo = sizeof(priv->d[0]) * priv->top; 297 if (todo > sizeof(private_bytes)) { 298 /* No reasonable DSA or ECDSA key should have a private key 299 * this large and we don't handle this case in order to avoid 300 * leaking the length of the private key. */ 301 OPENSSL_PUT_ERROR(BN, BN_R_PRIVATE_KEY_TOO_LARGE); 302 goto err; 303 } 304 OPENSSL_memcpy(private_bytes, priv->d, todo); 305 OPENSSL_memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); 306 307 for (attempt = 0;; attempt++) { 308 for (done = 0; done < num_k_bytes;) { 309 if (!RAND_bytes(random_bytes, sizeof(random_bytes))) { 310 goto err; 311 } 312 SHA512_Init(&sha); 313 SHA512_Update(&sha, &attempt, sizeof(attempt)); 314 SHA512_Update(&sha, &done, sizeof(done)); 315 SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); 316 SHA512_Update(&sha, message, message_len); 317 SHA512_Update(&sha, random_bytes, sizeof(random_bytes)); 318 SHA512_Final(digest, &sha); 319 320 todo = num_k_bytes - done; 321 if (todo > SHA512_DIGEST_LENGTH) { 322 todo = SHA512_DIGEST_LENGTH; 323 } 324 OPENSSL_memcpy(k_bytes + done, digest, todo); 325 done += todo; 326 } 327 328 k_bytes[0] &= 0xff >> bits_to_mask; 329 330 if (!BN_bin2bn(k_bytes, num_k_bytes, out)) { 331 goto err; 332 } 333 if (BN_cmp(out, range) < 0) { 334 break; 335 } 336 } 337 338 ret = 1; 339 340 err: 341 OPENSSL_free(k_bytes); 342 return ret; 343 } 344
