1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
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@cryptsoft.com).
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.
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
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@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@cryptsoft.com)"
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
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.]
57 /* ====================================================================
58 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
60 * Redistribution and use in source and binary forms, with or without
61 * modification, are permitted provided that the following conditions
64 * 1. Redistributions of source code must retain the above copyright
65 * notice, this list of conditions and the following disclaimer.
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
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/)"
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@openssl.org.
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.
86 * 6. Redistributions of any form whatsoever must retain the following
88 * "This product includes software developed by the OpenSSL Project
89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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 * ====================================================================
105 * This product includes cryptographic software written by Eric Young
106 * (eay@cryptsoft.com). This product includes software written by Tim
107 * Hudson (tjh@cryptsoft.com).
113 #include "internal/cryptlib.h"
115 #include <openssl/rand.h>
116 #include <openssl/sha.h>
118 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
120 unsigned char *buf = NULL;
121 int ret = 0, bit, bytes, mask;
124 if (bits < 0 || (bits == 1 && top > 0)) {
125 BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
134 bytes = (bits + 7) / 8;
135 bit = (bits - 1) % 8;
136 mask = 0xff << (bit + 1);
138 buf = OPENSSL_malloc(bytes);
140 BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE);
144 /* make a random number and set the top and bottom bits */
146 RAND_add(&tim, sizeof(tim), 0.0);
149 if (RAND_bytes(buf, bytes) <= 0)
152 if (RAND_bytes(buf, bytes) <= 0)
156 if (pseudorand == 2) {
158 * generate patterns that are more likely to trigger BN library bugs
163 for (i = 0; i < bytes; i++) {
164 if (RAND_bytes(&c, 1) <= 0)
166 if (c >= 128 && i > 0)
181 buf[0] |= (3 << (bit - 1));
184 buf[0] |= (1 << bit);
188 if (bottom) /* set bottom bit if requested */
190 if (!BN_bin2bn(buf, bytes, rnd))
194 OPENSSL_clear_free(buf, bytes);
199 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
201 return bnrand(0, rnd, bits, top, bottom);
204 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
206 return bnrand(1, rnd, bits, top, bottom);
209 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
211 return bnrand(2, rnd, bits, top, bottom);
214 /* random number r: 0 <= r < range */
215 static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range)
217 int (*bn_rand) (BIGNUM *, int, int, int) =
218 pseudo ? BN_pseudo_rand : BN_rand;
222 if (range->neg || BN_is_zero(range)) {
223 BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
227 n = BN_num_bits(range); /* n > 0 */
229 /* BN_is_bit_set(range, n - 1) always holds */
233 else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
235 * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer
239 if (!bn_rand(r, n + 1, -1, 0))
242 * If r < 3*range, use r := r MOD range (which is either r, r -
243 * range, or r - 2*range). Otherwise, iterate once more. Since
244 * 3*range = 11..._2, each iteration succeeds with probability >=
247 if (BN_cmp(r, range) >= 0) {
248 if (!BN_sub(r, r, range))
250 if (BN_cmp(r, range) >= 0)
251 if (!BN_sub(r, r, range))
256 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
261 while (BN_cmp(r, range) >= 0);
264 /* range = 11..._2 or range = 101..._2 */
265 if (!bn_rand(r, n, -1, 0))
269 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);
273 while (BN_cmp(r, range) >= 0);
280 int BN_rand_range(BIGNUM *r, const BIGNUM *range)
282 return bn_rand_range(0, r, range);
285 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range)
287 return bn_rand_range(1, r, range);
291 * BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike
292 * BN_rand_range, it also includes the contents of |priv| and |message| in
293 * the generation so that an RNG failure isn't fatal as long as |priv|
294 * remains secret. This is intended for use in DSA and ECDSA where an RNG
295 * weakness leads directly to private key exposure unless this function is
298 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range,
299 const BIGNUM *priv, const unsigned char *message,
300 size_t message_len, BN_CTX *ctx)
304 * We use 512 bits of random data per iteration to ensure that we have at
305 * least |range| bits of randomness.
307 unsigned char random_bytes[64];
308 unsigned char digest[SHA512_DIGEST_LENGTH];
310 /* We generate |range|+8 bytes of random output. */
311 const unsigned num_k_bytes = BN_num_bytes(range) + 8;
312 unsigned char private_bytes[96];
313 unsigned char *k_bytes;
316 k_bytes = OPENSSL_malloc(num_k_bytes);
320 /* We copy |priv| into a local buffer to avoid exposing its length. */
321 todo = sizeof(priv->d[0]) * priv->top;
322 if (todo > sizeof(private_bytes)) {
324 * No reasonable DSA or ECDSA key should have a private key this
325 * large and we don't handle this case in order to avoid leaking the
326 * length of the private key.
328 BNerr(BN_F_BN_GENERATE_DSA_NONCE, BN_R_PRIVATE_KEY_TOO_LARGE);
331 memcpy(private_bytes, priv->d, todo);
332 memset(private_bytes + todo, 0, sizeof(private_bytes) - todo);
334 for (done = 0; done < num_k_bytes;) {
335 if (RAND_bytes(random_bytes, sizeof(random_bytes)) != 1)
338 SHA512_Update(&sha, &done, sizeof(done));
339 SHA512_Update(&sha, private_bytes, sizeof(private_bytes));
340 SHA512_Update(&sha, message, message_len);
341 SHA512_Update(&sha, random_bytes, sizeof(random_bytes));
342 SHA512_Final(digest, &sha);
344 todo = num_k_bytes - done;
345 if (todo > SHA512_DIGEST_LENGTH)
346 todo = SHA512_DIGEST_LENGTH;
347 memcpy(k_bytes + done, digest, todo);
351 if (!BN_bin2bn(k_bytes, num_k_bytes, out))
353 if (BN_mod(out, out, range, ctx) != 1)
358 OPENSSL_free(k_bytes);