1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
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.
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@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@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)"
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@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@cryptsoft.com). This product includes software written by Tim
107 * Hudson (tjh@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
BN_rand(BIGNUM * rnd,int bits,int top,int bottom)118 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) {
119 uint8_t *buf = NULL;
120 int ret = 0, bit, bytes, mask;
121
122 if (rnd == NULL) {
123 return 0;
124 }
125
126 if (bits == 0) {
127 BN_zero(rnd);
128 return 1;
129 }
130
131 bytes = (bits + 7) / 8;
132 bit = (bits - 1) % 8;
133 mask = 0xff << (bit + 1);
134
135 buf = OPENSSL_malloc(bytes);
136 if (buf == NULL) {
137 OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE);
138 goto err;
139 }
140
141 /* Make a random number and set the top and bottom bits. */
142 if (!RAND_bytes(buf, bytes)) {
143 goto err;
144 }
145
146 if (top != -1) {
147 if (top && bits > 1) {
148 if (bit == 0) {
149 buf[0] = 1;
150 buf[1] |= 0x80;
151 } else {
152 buf[0] |= (3 << (bit - 1));
153 }
154 } else {
155 buf[0] |= (1 << bit);
156 }
157 }
158
159 buf[0] &= ~mask;
160
161 /* set bottom bit if requested */
162 if (bottom) {
163 buf[bytes - 1] |= 1;
164 }
165
166 if (!BN_bin2bn(buf, bytes, rnd)) {
167 goto err;
168 }
169
170 ret = 1;
171
172 err:
173 if (buf != NULL) {
174 OPENSSL_cleanse(buf, bytes);
175 OPENSSL_free(buf);
176 }
177 return (ret);
178 }
179
BN_pseudo_rand(BIGNUM * rnd,int bits,int top,int bottom)180 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) {
181 return BN_rand(rnd, bits, top, bottom);
182 }
183
BN_rand_range(BIGNUM * r,const BIGNUM * range)184 int BN_rand_range(BIGNUM *r, const BIGNUM *range) {
185 unsigned n;
186 unsigned count = 100;
187
188 if (range->neg || BN_is_zero(range)) {
189 OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE);
190 return 0;
191 }
192
193 n = BN_num_bits(range); /* n > 0 */
194
195 /* BN_is_bit_set(range, n - 1) always holds */
196 if (n == 1) {
197 BN_zero(r);
198 } else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
199 /* range = 100..._2,
200 * so 3*range (= 11..._2) is exactly one bit longer than range */
201 do {
202 if (!BN_rand(r, n + 1, -1 /* don't set most significant bits */,
203 0 /* don't set least significant bits */)) {
204 return 0;
205 }
206
207 /* If r < 3*range, use r := r MOD range (which is either r, r - range, or
208 * r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each
209 * iteration succeeds with probability >= .75. */
210 if (BN_cmp(r, range) >= 0) {
211 if (!BN_sub(r, r, range)) {
212 return 0;
213 }
214 if (BN_cmp(r, range) >= 0) {
215 if (!BN_sub(r, r, range)) {
216 return 0;
217 }
218 }
219 }
220
221 if (!--count) {
222 OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS);
223 return 0;
224 }
225 } while (BN_cmp(r, range) >= 0);
226 } else {
227 do {
228 /* range = 11..._2 or range = 101..._2 */
229 if (!BN_rand(r, n, -1, 0)) {
230 return 0;
231 }
232
233 if (!--count) {
234 OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS);
235 return 0;
236 }
237 } while (BN_cmp(r, range) >= 0);
238 }
239
240 return 1;
241 }
242
BN_pseudo_rand_range(BIGNUM * r,const BIGNUM * range)243 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) {
244 return BN_rand_range(r, range);
245 }
246
BN_generate_dsa_nonce(BIGNUM * out,const BIGNUM * range,const BIGNUM * priv,const uint8_t * message,size_t message_len,BN_CTX * ctx)247 int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv,
248 const uint8_t *message, size_t message_len,
249 BN_CTX *ctx) {
250 SHA512_CTX sha;
251 /* We use 512 bits of random data per iteration to
252 * ensure that we have at least |range| bits of randomness. */
253 uint8_t random_bytes[64];
254 uint8_t digest[SHA512_DIGEST_LENGTH];
255 size_t done, todo, attempt;
256 const unsigned num_k_bytes = BN_num_bytes(range);
257 const unsigned bits_to_mask = (8 - (BN_num_bits(range) % 8)) % 8;
258 uint8_t private_bytes[96];
259 uint8_t *k_bytes = NULL;
260 int ret = 0;
261
262 if (out == NULL) {
263 return 0;
264 }
265
266 if (BN_is_zero(range)) {
267 OPENSSL_PUT_ERROR(BN, BN_R_DIV_BY_ZERO);
268 goto err;
269 }
270
271 k_bytes = OPENSSL_malloc(num_k_bytes);
272 if (!k_bytes) {
273 OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE);
274 goto err;
275 }
276
277 /* We copy |priv| into a local buffer to avoid furthur exposing its
278 * length. */
279 todo = sizeof(priv->d[0]) * priv->top;
280 if (todo > sizeof(private_bytes)) {
281 /* No reasonable DSA or ECDSA key should have a private key
282 * this large and we don't handle this case in order to avoid
283 * leaking the length of the private key. */
284 OPENSSL_PUT_ERROR(BN, BN_R_PRIVATE_KEY_TOO_LARGE);
285 goto err;
286 }
287 memcpy(private_bytes, priv->d, todo);
288 memset(private_bytes + todo, 0, sizeof(private_bytes) - todo);
289
290 for (attempt = 0;; attempt++) {
291 for (done = 0; done < num_k_bytes;) {
292 if (!RAND_bytes(random_bytes, sizeof(random_bytes))) {
293 goto err;
294 }
295 SHA512_Init(&sha);
296 SHA512_Update(&sha, &attempt, sizeof(attempt));
297 SHA512_Update(&sha, &done, sizeof(done));
298 SHA512_Update(&sha, private_bytes, sizeof(private_bytes));
299 SHA512_Update(&sha, message, message_len);
300 SHA512_Update(&sha, random_bytes, sizeof(random_bytes));
301 SHA512_Final(digest, &sha);
302
303 todo = num_k_bytes - done;
304 if (todo > SHA512_DIGEST_LENGTH) {
305 todo = SHA512_DIGEST_LENGTH;
306 }
307 memcpy(k_bytes + done, digest, todo);
308 done += todo;
309 }
310
311 k_bytes[0] &= 0xff >> bits_to_mask;
312
313 if (!BN_bin2bn(k_bytes, num_k_bytes, out)) {
314 goto err;
315 }
316 if (BN_cmp(out, range) < 0) {
317 break;
318 }
319 }
320
321 ret = 1;
322
323 err:
324 OPENSSL_free(k_bytes);
325 return ret;
326 }
327