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 <openssl/err.h> 112 #include <openssl/mem.h> 113 #include <openssl/rand.h> 114 #include <openssl/sha.h> 115 116 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { 117 uint8_t *buf = NULL; 118 int ret = 0, bit, bytes, mask; 119 120 if (rnd == NULL) { 121 return 0; 122 } 123 124 if (bits == 0) { 125 BN_zero(rnd); 126 return 1; 127 } 128 129 bytes = (bits + 7) / 8; 130 bit = (bits - 1) % 8; 131 mask = 0xff << (bit + 1); 132 133 buf = OPENSSL_malloc(bytes); 134 if (buf == NULL) { 135 OPENSSL_PUT_ERROR(BN, BN_rand, ERR_R_MALLOC_FAILURE); 136 goto err; 137 } 138 139 /* make a random number and set the top and bottom bits */ 140 if (RAND_pseudo_bytes(buf, bytes) <= 0) 141 goto err; 142 143 if (top != -1) { 144 if (top) { 145 if (bit == 0) { 146 buf[0] = 1; 147 buf[1] |= 0x80; 148 } else { 149 buf[0] |= (3 << (bit - 1)); 150 } 151 } else { 152 buf[0] |= (1 << bit); 153 } 154 } 155 156 buf[0] &= ~mask; 157 158 /* set bottom bit if requested */ 159 if (bottom) { 160 buf[bytes - 1] |= 1; 161 } 162 163 if (!BN_bin2bn(buf, bytes, rnd)) { 164 goto err; 165 } 166 167 ret = 1; 168 169 err: 170 if (buf != NULL) { 171 OPENSSL_cleanse(buf, bytes); 172 OPENSSL_free(buf); 173 } 174 return (ret); 175 } 176 177 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { 178 return BN_rand(rnd, bits, top, bottom); 179 } 180 181 int BN_rand_range(BIGNUM *r, const BIGNUM *range) { 182 unsigned n; 183 unsigned count = 100; 184 185 if (range->neg || BN_is_zero(range)) { 186 OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_INVALID_RANGE); 187 return 0; 188 } 189 190 n = BN_num_bits(range); /* n > 0 */ 191 192 /* BN_is_bit_set(range, n - 1) always holds */ 193 if (n == 1) { 194 BN_zero(r); 195 } else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) { 196 /* range = 100..._2, 197 * so 3*range (= 11..._2) is exactly one bit longer than range */ 198 do { 199 if (!BN_rand(r, n + 1, -1 /* don't set most significant bits */, 200 0 /* don't set least significant bits */)) { 201 return 0; 202 } 203 204 /* If r < 3*range, use r := r MOD range (which is either r, r - range, or 205 * r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each 206 * iteration succeeds with probability >= .75. */ 207 if (BN_cmp(r, range) >= 0) { 208 if (!BN_sub(r, r, range)) { 209 return 0; 210 } 211 if (BN_cmp(r, range) >= 0) { 212 if (!BN_sub(r, r, range)) { 213 return 0; 214 } 215 } 216 } 217 218 if (!--count) { 219 OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_TOO_MANY_ITERATIONS); 220 return 0; 221 } 222 } while (BN_cmp(r, range) >= 0); 223 } else { 224 do { 225 /* range = 11..._2 or range = 101..._2 */ 226 if (!BN_rand(r, n, -1, 0)) { 227 return 0; 228 } 229 230 if (!--count) { 231 OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_TOO_MANY_ITERATIONS); 232 return 0; 233 } 234 } while (BN_cmp(r, range) >= 0); 235 } 236 237 return 1; 238 } 239 240 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) { 241 return BN_rand_range(r, range); 242 } 243 244 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv, 245 const uint8_t *message, size_t message_len, 246 BN_CTX *ctx) { 247 SHA512_CTX sha; 248 /* We use 512 bits of random data per iteration to 249 * ensure that we have at least |range| bits of randomness. */ 250 uint8_t random_bytes[64]; 251 uint8_t digest[SHA512_DIGEST_LENGTH]; 252 size_t done, todo, attempt; 253 const unsigned num_k_bytes = BN_num_bytes(range); 254 const unsigned bits_to_mask = (8 - (BN_num_bits(range) % 8)) % 8; 255 uint8_t private_bytes[96]; 256 uint8_t *k_bytes = NULL; 257 int ret = 0; 258 259 if (out == NULL) { 260 return 0; 261 } 262 263 if (BN_is_zero(range)) { 264 OPENSSL_PUT_ERROR(BN, BN_generate_dsa_nonce, BN_R_DIV_BY_ZERO); 265 goto err; 266 } 267 268 k_bytes = OPENSSL_malloc(num_k_bytes); 269 if (!k_bytes) { 270 OPENSSL_PUT_ERROR(BN, BN_generate_dsa_nonce, ERR_R_MALLOC_FAILURE); 271 goto err; 272 } 273 274 /* We copy |priv| into a local buffer to avoid furthur exposing its 275 * length. */ 276 todo = sizeof(priv->d[0]) * priv->top; 277 if (todo > sizeof(private_bytes)) { 278 /* No reasonable DSA or ECDSA key should have a private key 279 * this large and we don't handle this case in order to avoid 280 * leaking the length of the private key. */ 281 OPENSSL_PUT_ERROR(BN, BN_generate_dsa_nonce, BN_R_PRIVATE_KEY_TOO_LARGE); 282 goto err; 283 } 284 memcpy(private_bytes, priv->d, todo); 285 memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); 286 287 for (attempt = 0;; attempt++) { 288 for (done = 0; done < num_k_bytes;) { 289 if (RAND_pseudo_bytes(random_bytes, sizeof(random_bytes)) != 1) { 290 goto err; 291 } 292 SHA512_Init(&sha); 293 SHA512_Update(&sha, &attempt, sizeof(attempt)); 294 SHA512_Update(&sha, &done, sizeof(done)); 295 SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); 296 SHA512_Update(&sha, message, message_len); 297 SHA512_Update(&sha, random_bytes, sizeof(random_bytes)); 298 SHA512_Final(digest, &sha); 299 300 todo = num_k_bytes - done; 301 if (todo > SHA512_DIGEST_LENGTH) { 302 todo = SHA512_DIGEST_LENGTH; 303 } 304 memcpy(k_bytes + done, digest, todo); 305 done += todo; 306 } 307 308 k_bytes[0] &= 0xff >> bits_to_mask; 309 310 if (!BN_bin2bn(k_bytes, num_k_bytes, out)) { 311 goto err; 312 } 313 if (BN_cmp(out, range) < 0) { 314 break; 315 } 316 } 317 318 ret = 1; 319 320 err: 321 if (k_bytes) { 322 OPENSSL_free(k_bytes); 323 } 324 return ret; 325 } 326
