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d02b48c6 | 1 | /* crypto/bn/bn_rand.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
3 | * All rights reserved. |
4 | * | |
5 | * This package is an SSL implementation written | |
6 | * by Eric Young (eay@cryptsoft.com). | |
7 | * The implementation was written so as to conform with Netscapes SSL. | |
0f113f3e | 8 | * |
d02b48c6 RE |
9 | * This library is free for commercial and non-commercial use as long as |
10 | * the following conditions are aheared to. The following conditions | |
11 | * apply to all code found in this distribution, be it the RC4, RSA, | |
12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
13 | * included with this distribution is covered by the same copyright terms | |
14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
0f113f3e | 15 | * |
d02b48c6 RE |
16 | * Copyright remains Eric Young's, and as such any Copyright notices in |
17 | * the code are not to be removed. | |
18 | * If this package is used in a product, Eric Young should be given attribution | |
19 | * as the author of the parts of the library used. | |
20 | * This can be in the form of a textual message at program startup or | |
21 | * in documentation (online or textual) provided with the package. | |
0f113f3e | 22 | * |
d02b48c6 RE |
23 | * Redistribution and use in source and binary forms, with or without |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * 3. All advertising materials mentioning features or use of this software | |
32 | * must display the following acknowledgement: | |
33 | * "This product includes cryptographic software written by | |
34 | * Eric Young (eay@cryptsoft.com)" | |
35 | * The word 'cryptographic' can be left out if the rouines from the library | |
36 | * being used are not cryptographic related :-). | |
0f113f3e | 37 | * 4. If you include any Windows specific code (or a derivative thereof) from |
d02b48c6 RE |
38 | * the apps directory (application code) you must include an acknowledgement: |
39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
0f113f3e | 40 | * |
d02b48c6 RE |
41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
51 | * SUCH DAMAGE. | |
0f113f3e | 52 | * |
d02b48c6 RE |
53 | * The licence and distribution terms for any publically available version or |
54 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
55 | * copied and put under another distribution licence | |
56 | * [including the GNU Public Licence.] | |
57 | */ | |
983495c4 BM |
58 | /* ==================================================================== |
59 | * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. | |
60 | * | |
61 | * Redistribution and use in source and binary forms, with or without | |
62 | * modification, are permitted provided that the following conditions | |
63 | * are met: | |
64 | * | |
65 | * 1. Redistributions of source code must retain the above copyright | |
0f113f3e | 66 | * notice, this list of conditions and the following disclaimer. |
983495c4 BM |
67 | * |
68 | * 2. Redistributions in binary form must reproduce the above copyright | |
69 | * notice, this list of conditions and the following disclaimer in | |
70 | * the documentation and/or other materials provided with the | |
71 | * distribution. | |
72 | * | |
73 | * 3. All advertising materials mentioning features or use of this | |
74 | * software must display the following acknowledgment: | |
75 | * "This product includes software developed by the OpenSSL Project | |
76 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |
77 | * | |
78 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
79 | * endorse or promote products derived from this software without | |
80 | * prior written permission. For written permission, please contact | |
81 | * openssl-core@openssl.org. | |
82 | * | |
83 | * 5. Products derived from this software may not be called "OpenSSL" | |
84 | * nor may "OpenSSL" appear in their names without prior written | |
85 | * permission of the OpenSSL Project. | |
86 | * | |
87 | * 6. Redistributions of any form whatsoever must retain the following | |
88 | * acknowledgment: | |
89 | * "This product includes software developed by the OpenSSL Project | |
90 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |
91 | * | |
92 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
93 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
94 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
95 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
96 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
97 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
98 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
99 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
100 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
101 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
102 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
103 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
104 | * ==================================================================== | |
105 | * | |
106 | * This product includes cryptographic software written by Eric Young | |
107 | * (eay@cryptsoft.com). This product includes software written by Tim | |
108 | * Hudson (tjh@cryptsoft.com). | |
109 | * | |
110 | */ | |
d02b48c6 RE |
111 | |
112 | #include <stdio.h> | |
113 | #include <time.h> | |
114 | #include "cryptlib.h" | |
115 | #include "bn_lcl.h" | |
ec577822 | 116 | #include <openssl/rand.h> |
8a99cb29 | 117 | #include <openssl/sha.h> |
d02b48c6 | 118 | |
38e33cef | 119 | static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom) |
0f113f3e MC |
120 | { |
121 | unsigned char *buf = NULL; | |
122 | int ret = 0, bit, bytes, mask; | |
123 | time_t tim; | |
124 | ||
125 | if (bits == 0) { | |
126 | BN_zero(rnd); | |
127 | return 1; | |
128 | } | |
129 | ||
130 | bytes = (bits + 7) / 8; | |
131 | bit = (bits - 1) % 8; | |
132 | mask = 0xff << (bit + 1); | |
133 | ||
134 | buf = (unsigned char *)OPENSSL_malloc(bytes); | |
135 | if (buf == NULL) { | |
136 | BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE); | |
137 | goto err; | |
138 | } | |
139 | ||
140 | /* make a random number and set the top and bottom bits */ | |
141 | time(&tim); | |
142 | RAND_add(&tim, sizeof(tim), 0.0); | |
143 | ||
144 | if (pseudorand) { | |
145 | if (RAND_pseudo_bytes(buf, bytes) == -1) | |
146 | goto err; | |
147 | } else { | |
148 | if (RAND_bytes(buf, bytes) <= 0) | |
149 | goto err; | |
150 | } | |
38e33cef | 151 | |
111482cf | 152 | #if 1 |
0f113f3e MC |
153 | if (pseudorand == 2) { |
154 | /* | |
155 | * generate patterns that are more likely to trigger BN library bugs | |
156 | */ | |
157 | int i; | |
158 | unsigned char c; | |
159 | ||
160 | for (i = 0; i < bytes; i++) { | |
161 | RAND_pseudo_bytes(&c, 1); | |
162 | if (c >= 128 && i > 0) | |
163 | buf[i] = buf[i - 1]; | |
164 | else if (c < 42) | |
165 | buf[i] = 0; | |
166 | else if (c < 84) | |
167 | buf[i] = 255; | |
168 | } | |
169 | } | |
111482cf UM |
170 | #endif |
171 | ||
0f113f3e MC |
172 | if (top != -1) { |
173 | if (top) { | |
174 | if (bit == 0) { | |
175 | buf[0] = 1; | |
176 | buf[1] |= 0x80; | |
177 | } else { | |
178 | buf[0] |= (3 << (bit - 1)); | |
179 | } | |
180 | } else { | |
181 | buf[0] |= (1 << bit); | |
182 | } | |
183 | } | |
184 | buf[0] &= ~mask; | |
185 | if (bottom) /* set bottom bit if requested */ | |
186 | buf[bytes - 1] |= 1; | |
187 | if (!BN_bin2bn(buf, bytes, rnd)) | |
188 | goto err; | |
189 | ret = 1; | |
190 | err: | |
191 | if (buf != NULL) { | |
192 | OPENSSL_cleanse(buf, bytes); | |
193 | OPENSSL_free(buf); | |
194 | } | |
195 | bn_check_top(rnd); | |
196 | return (ret); | |
197 | } | |
198 | ||
199 | int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
200 | { | |
201 | return bnrand(0, rnd, bits, top, bottom); | |
202 | } | |
203 | ||
204 | int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
205 | { | |
206 | return bnrand(1, rnd, bits, top, bottom); | |
207 | } | |
111482cf UM |
208 | |
209 | #if 1 | |
0f113f3e MC |
210 | int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) |
211 | { | |
212 | return bnrand(2, rnd, bits, top, bottom); | |
213 | } | |
111482cf | 214 | #endif |
57e7d3ce | 215 | |
e3068929 | 216 | /* random number r: 0 <= r < range */ |
0d6f9c71 | 217 | static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) |
0f113f3e MC |
218 | { |
219 | int (*bn_rand) (BIGNUM *, int, int, int) = | |
220 | pseudo ? BN_pseudo_rand : BN_rand; | |
221 | int n; | |
222 | int count = 100; | |
223 | ||
224 | if (range->neg || BN_is_zero(range)) { | |
225 | BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); | |
226 | return 0; | |
227 | } | |
228 | ||
229 | n = BN_num_bits(range); /* n > 0 */ | |
230 | ||
231 | /* BN_is_bit_set(range, n - 1) always holds */ | |
232 | ||
233 | if (n == 1) | |
234 | BN_zero(r); | |
235 | else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) { | |
236 | /* | |
237 | * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer | |
238 | * than range | |
239 | */ | |
240 | do { | |
241 | if (!bn_rand(r, n + 1, -1, 0)) | |
242 | return 0; | |
243 | /* | |
244 | * If r < 3*range, use r := r MOD range (which is either r, r - | |
245 | * range, or r - 2*range). Otherwise, iterate once more. Since | |
246 | * 3*range = 11..._2, each iteration succeeds with probability >= | |
247 | * .75. | |
248 | */ | |
249 | if (BN_cmp(r, range) >= 0) { | |
250 | if (!BN_sub(r, r, range)) | |
251 | return 0; | |
252 | if (BN_cmp(r, range) >= 0) | |
253 | if (!BN_sub(r, r, range)) | |
254 | return 0; | |
255 | } | |
256 | ||
257 | if (!--count) { | |
258 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); | |
259 | return 0; | |
260 | } | |
261 | ||
262 | } | |
263 | while (BN_cmp(r, range) >= 0); | |
264 | } else { | |
265 | do { | |
266 | /* range = 11..._2 or range = 101..._2 */ | |
267 | if (!bn_rand(r, n, -1, 0)) | |
268 | return 0; | |
269 | ||
270 | if (!--count) { | |
271 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); | |
272 | return 0; | |
273 | } | |
274 | } | |
275 | while (BN_cmp(r, range) >= 0); | |
276 | } | |
277 | ||
278 | bn_check_top(r); | |
279 | return 1; | |
280 | } | |
281 | ||
282 | int BN_rand_range(BIGNUM *r, const BIGNUM *range) | |
283 | { | |
284 | return bn_rand_range(0, r, range); | |
285 | } | |
286 | ||
287 | int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) | |
288 | { | |
289 | return bn_rand_range(1, r, range); | |
290 | } | |
8a99cb29 AL |
291 | |
292 | #ifndef OPENSSL_NO_SHA512 | |
0f113f3e MC |
293 | /* |
294 | * BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike | |
295 | * BN_rand_range, it also includes the contents of |priv| and |message| in | |
296 | * the generation so that an RNG failure isn't fatal as long as |priv| | |
297 | * remains secret. This is intended for use in DSA and ECDSA where an RNG | |
298 | * weakness leads directly to private key exposure unless this function is | |
299 | * used. | |
300 | */ | |
301 | int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, | |
302 | const BIGNUM *priv, const unsigned char *message, | |
303 | size_t message_len, BN_CTX *ctx) | |
304 | { | |
305 | SHA512_CTX sha; | |
306 | /* | |
307 | * We use 512 bits of random data per iteration to ensure that we have at | |
308 | * least |range| bits of randomness. | |
309 | */ | |
310 | unsigned char random_bytes[64]; | |
311 | unsigned char digest[SHA512_DIGEST_LENGTH]; | |
312 | unsigned done, todo; | |
313 | /* We generate |range|+8 bytes of random output. */ | |
314 | const unsigned num_k_bytes = BN_num_bytes(range) + 8; | |
315 | unsigned char private_bytes[96]; | |
316 | unsigned char *k_bytes; | |
317 | int ret = 0; | |
318 | ||
319 | k_bytes = OPENSSL_malloc(num_k_bytes); | |
320 | if (!k_bytes) | |
321 | goto err; | |
322 | ||
323 | /* We copy |priv| into a local buffer to avoid exposing its length. */ | |
324 | todo = sizeof(priv->d[0]) * priv->top; | |
325 | if (todo > sizeof(private_bytes)) { | |
326 | /* | |
327 | * No reasonable DSA or ECDSA key should have a private key this | |
328 | * large and we don't handle this case in order to avoid leaking the | |
329 | * length of the private key. | |
330 | */ | |
331 | BNerr(BN_F_BN_GENERATE_DSA_NONCE, BN_R_PRIVATE_KEY_TOO_LARGE); | |
332 | goto err; | |
333 | } | |
334 | memcpy(private_bytes, priv->d, todo); | |
335 | memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); | |
336 | ||
337 | for (done = 0; done < num_k_bytes;) { | |
338 | if (RAND_bytes(random_bytes, sizeof(random_bytes)) != 1) | |
339 | goto err; | |
340 | SHA512_Init(&sha); | |
341 | SHA512_Update(&sha, &done, sizeof(done)); | |
342 | SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); | |
343 | SHA512_Update(&sha, message, message_len); | |
344 | SHA512_Update(&sha, random_bytes, sizeof(random_bytes)); | |
345 | SHA512_Final(digest, &sha); | |
346 | ||
347 | todo = num_k_bytes - done; | |
348 | if (todo > SHA512_DIGEST_LENGTH) | |
349 | todo = SHA512_DIGEST_LENGTH; | |
350 | memcpy(k_bytes + done, digest, todo); | |
351 | done += todo; | |
352 | } | |
353 | ||
354 | if (!BN_bin2bn(k_bytes, num_k_bytes, out)) | |
355 | goto err; | |
356 | if (BN_mod(out, out, range, ctx) != 1) | |
357 | goto err; | |
358 | ret = 1; | |
359 | ||
360 | err: | |
361 | if (k_bytes) | |
362 | OPENSSL_free(k_bytes); | |
363 | return ret; | |
364 | } | |
365 | #endif /* OPENSSL_NO_SHA512 */ |