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 #include <openssl/type_check.h> 118 119 #include "../../internal.h" 120 #include "../rand/internal.h" 121 122 123 static const uint8_t kDefaultAdditionalData[32] = {0}; 124 125 static int bn_rand_with_additional_data(BIGNUM *rnd, int bits, int top, 126 int bottom, 127 const uint8_t additional_data[32]) { 128 uint8_t *buf = NULL; 129 int ret = 0, bit, bytes, mask; 130 131 if (rnd == NULL) { 132 return 0; 133 } 134 135 if (top != BN_RAND_TOP_ANY && top != BN_RAND_TOP_ONE && 136 top != BN_RAND_TOP_TWO) { 137 OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); 138 return 0; 139 } 140 141 if (bottom != BN_RAND_BOTTOM_ANY && bottom != BN_RAND_BOTTOM_ODD) { 142 OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); 143 return 0; 144 } 145 146 if (bits == 0) { 147 BN_zero(rnd); 148 return 1; 149 } 150 151 bytes = (bits + 7) / 8; 152 bit = (bits - 1) % 8; 153 mask = 0xff << (bit + 1); 154 155 buf = OPENSSL_malloc(bytes); 156 if (buf == NULL) { 157 OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); 158 goto err; 159 } 160 161 /* Make a random number and set the top and bottom bits. */ 162 RAND_bytes_with_additional_data(buf, bytes, additional_data); 163 164 if (top != BN_RAND_TOP_ANY) { 165 if (top == BN_RAND_TOP_TWO && bits > 1) { 166 if (bit == 0) { 167 buf[0] = 1; 168 buf[1] |= 0x80; 169 } else { 170 buf[0] |= (3 << (bit - 1)); 171 } 172 } else { 173 buf[0] |= (1 << bit); 174 } 175 } 176 177 buf[0] &= ~mask; 178 179 /* Set the bottom bit if requested, */ 180 if (bottom == BN_RAND_BOTTOM_ODD) { 181 buf[bytes - 1] |= 1; 182 } 183 184 if (!BN_bin2bn(buf, bytes, rnd)) { 185 goto err; 186 } 187 188 ret = 1; 189 190 err: 191 if (buf != NULL) { 192 OPENSSL_cleanse(buf, bytes); 193 OPENSSL_free(buf); 194 } 195 return (ret); 196 } 197 198 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { 199 return bn_rand_with_additional_data(rnd, bits, top, bottom, 200 kDefaultAdditionalData); 201 } 202 203 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { 204 return BN_rand(rnd, bits, top, bottom); 205 } 206 207 static int bn_rand_range_with_additional_data( 208 BIGNUM *r, BN_ULONG min_inclusive, const BIGNUM *max_exclusive, 209 const uint8_t additional_data[32]) { 210 if (BN_cmp_word(max_exclusive, min_inclusive) <= 0) { 211 OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE); 212 return 0; 213 } 214 215 /* This function is used to implement steps 4 through 7 of FIPS 186-4 216 * appendices B.4.2 and B.5.2. When called in those contexts, |max_exclusive| 217 * is n and |min_inclusive| is one. */ 218 unsigned count = 100; 219 unsigned n = BN_num_bits(max_exclusive); /* n > 0 */ 220 do { 221 if (!--count) { 222 OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS); 223 return 0; 224 } 225 226 if (/* steps 4 and 5 */ 227 !bn_rand_with_additional_data(r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY, 228 additional_data) || 229 /* step 7 */ 230 !BN_add_word(r, min_inclusive)) { 231 return 0; 232 } 233 234 /* Step 6. This loops if |r| >= |max_exclusive|. This is identical to 235 * checking |r| > |max_exclusive| - 1 or |r| - 1 > |max_exclusive| - 2, the 236 * formulation stated in FIPS 186-4. */ 237 } while (BN_cmp(r, max_exclusive) >= 0); 238 239 return 1; 240 } 241 242 int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive, 243 const BIGNUM *max_exclusive) { 244 return bn_rand_range_with_additional_data(r, min_inclusive, max_exclusive, 245 kDefaultAdditionalData); 246 } 247 248 int BN_rand_range(BIGNUM *r, const BIGNUM *range) { 249 return BN_rand_range_ex(r, 0, range); 250 } 251 252 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) { 253 return BN_rand_range(r, range); 254 } 255 256 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv, 257 const uint8_t *message, size_t message_len, 258 BN_CTX *ctx) { 259 /* We copy |priv| into a local buffer to avoid furthur exposing its 260 * length. */ 261 uint8_t private_bytes[96]; 262 size_t todo = sizeof(priv->d[0]) * priv->top; 263 if (todo > sizeof(private_bytes)) { 264 /* No reasonable DSA or ECDSA key should have a private key 265 * this large and we don't handle this case in order to avoid 266 * leaking the length of the private key. */ 267 OPENSSL_PUT_ERROR(BN, BN_R_PRIVATE_KEY_TOO_LARGE); 268 return 0; 269 } 270 OPENSSL_memcpy(private_bytes, priv->d, todo); 271 OPENSSL_memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); 272 273 /* Pass a SHA512 hash of the private key and message as additional data into 274 * the RBG. This is a hardening measure against entropy failure. */ 275 OPENSSL_COMPILE_ASSERT(SHA512_DIGEST_LENGTH >= 32, 276 additional_data_is_too_large_for_sha512); 277 SHA512_CTX sha; 278 uint8_t digest[SHA512_DIGEST_LENGTH]; 279 SHA512_Init(&sha); 280 SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); 281 SHA512_Update(&sha, message, message_len); 282 SHA512_Final(digest, &sha); 283 284 /* Select a value k from [1, range-1], following FIPS 186-4 appendix B.5.2. */ 285 return bn_rand_range_with_additional_data(out, 1, range, digest); 286 } 287
