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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) { | |
266483d2 | 145 | if (RAND_bytes(buf, bytes) <= 0) |
0f113f3e MC |
146 | goto err; |
147 | } else { | |
148 | if (RAND_bytes(buf, bytes) <= 0) | |
149 | goto err; | |
150 | } | |
38e33cef | 151 | |
0f113f3e MC |
152 | if (pseudorand == 2) { |
153 | /* | |
154 | * generate patterns that are more likely to trigger BN library bugs | |
155 | */ | |
156 | int i; | |
157 | unsigned char c; | |
158 | ||
159 | for (i = 0; i < bytes; i++) { | |
266483d2 MC |
160 | if (RAND_bytes(&c, 1) <= 0) |
161 | goto err; | |
0f113f3e MC |
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 | 170 | |
0f113f3e MC |
171 | if (top != -1) { |
172 | if (top) { | |
173 | if (bit == 0) { | |
174 | buf[0] = 1; | |
175 | buf[1] |= 0x80; | |
176 | } else { | |
177 | buf[0] |= (3 << (bit - 1)); | |
178 | } | |
179 | } else { | |
180 | buf[0] |= (1 << bit); | |
181 | } | |
182 | } | |
183 | buf[0] &= ~mask; | |
184 | if (bottom) /* set bottom bit if requested */ | |
185 | buf[bytes - 1] |= 1; | |
186 | if (!BN_bin2bn(buf, bytes, rnd)) | |
187 | goto err; | |
188 | ret = 1; | |
189 | err: | |
190 | if (buf != NULL) { | |
191 | OPENSSL_cleanse(buf, bytes); | |
192 | OPENSSL_free(buf); | |
193 | } | |
194 | bn_check_top(rnd); | |
195 | return (ret); | |
196 | } | |
197 | ||
198 | int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
199 | { | |
200 | return bnrand(0, rnd, bits, top, bottom); | |
201 | } | |
202 | ||
203 | int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
204 | { | |
205 | return bnrand(1, rnd, bits, top, bottom); | |
206 | } | |
111482cf | 207 | |
0f113f3e MC |
208 | int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) |
209 | { | |
210 | return bnrand(2, rnd, bits, top, bottom); | |
211 | } | |
57e7d3ce | 212 | |
e3068929 | 213 | /* random number r: 0 <= r < range */ |
0d6f9c71 | 214 | static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) |
0f113f3e MC |
215 | { |
216 | int (*bn_rand) (BIGNUM *, int, int, int) = | |
217 | pseudo ? BN_pseudo_rand : BN_rand; | |
218 | int n; | |
219 | int count = 100; | |
220 | ||
221 | if (range->neg || BN_is_zero(range)) { | |
222 | BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); | |
223 | return 0; | |
224 | } | |
225 | ||
226 | n = BN_num_bits(range); /* n > 0 */ | |
227 | ||
228 | /* BN_is_bit_set(range, n - 1) always holds */ | |
229 | ||
230 | if (n == 1) | |
231 | BN_zero(r); | |
232 | else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) { | |
233 | /* | |
234 | * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer | |
235 | * than range | |
236 | */ | |
237 | do { | |
238 | if (!bn_rand(r, n + 1, -1, 0)) | |
239 | return 0; | |
240 | /* | |
241 | * If r < 3*range, use r := r MOD range (which is either r, r - | |
242 | * range, or r - 2*range). Otherwise, iterate once more. Since | |
243 | * 3*range = 11..._2, each iteration succeeds with probability >= | |
244 | * .75. | |
245 | */ | |
246 | if (BN_cmp(r, range) >= 0) { | |
247 | if (!BN_sub(r, r, range)) | |
248 | return 0; | |
249 | if (BN_cmp(r, range) >= 0) | |
250 | if (!BN_sub(r, r, range)) | |
251 | return 0; | |
252 | } | |
253 | ||
254 | if (!--count) { | |
255 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); | |
256 | return 0; | |
257 | } | |
258 | ||
259 | } | |
260 | while (BN_cmp(r, range) >= 0); | |
261 | } else { | |
262 | do { | |
263 | /* range = 11..._2 or range = 101..._2 */ | |
264 | if (!bn_rand(r, n, -1, 0)) | |
265 | return 0; | |
266 | ||
267 | if (!--count) { | |
268 | BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); | |
269 | return 0; | |
270 | } | |
271 | } | |
272 | while (BN_cmp(r, range) >= 0); | |
273 | } | |
274 | ||
275 | bn_check_top(r); | |
276 | return 1; | |
277 | } | |
278 | ||
279 | int BN_rand_range(BIGNUM *r, const BIGNUM *range) | |
280 | { | |
281 | return bn_rand_range(0, r, range); | |
282 | } | |
283 | ||
284 | int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) | |
285 | { | |
286 | return bn_rand_range(1, r, range); | |
287 | } | |
8a99cb29 | 288 | |
0f113f3e MC |
289 | /* |
290 | * BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike | |
291 | * BN_rand_range, it also includes the contents of |priv| and |message| in | |
292 | * the generation so that an RNG failure isn't fatal as long as |priv| | |
293 | * remains secret. This is intended for use in DSA and ECDSA where an RNG | |
294 | * weakness leads directly to private key exposure unless this function is | |
295 | * used. | |
296 | */ | |
297 | int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, | |
298 | const BIGNUM *priv, const unsigned char *message, | |
299 | size_t message_len, BN_CTX *ctx) | |
300 | { | |
301 | SHA512_CTX sha; | |
302 | /* | |
303 | * We use 512 bits of random data per iteration to ensure that we have at | |
304 | * least |range| bits of randomness. | |
305 | */ | |
306 | unsigned char random_bytes[64]; | |
307 | unsigned char digest[SHA512_DIGEST_LENGTH]; | |
308 | unsigned done, todo; | |
309 | /* We generate |range|+8 bytes of random output. */ | |
310 | const unsigned num_k_bytes = BN_num_bytes(range) + 8; | |
311 | unsigned char private_bytes[96]; | |
312 | unsigned char *k_bytes; | |
313 | int ret = 0; | |
314 | ||
315 | k_bytes = OPENSSL_malloc(num_k_bytes); | |
316 | if (!k_bytes) | |
317 | goto err; | |
318 | ||
319 | /* We copy |priv| into a local buffer to avoid exposing its length. */ | |
320 | todo = sizeof(priv->d[0]) * priv->top; | |
321 | if (todo > sizeof(private_bytes)) { | |
322 | /* | |
323 | * No reasonable DSA or ECDSA key should have a private key this | |
324 | * large and we don't handle this case in order to avoid leaking the | |
325 | * length of the private key. | |
326 | */ | |
327 | BNerr(BN_F_BN_GENERATE_DSA_NONCE, BN_R_PRIVATE_KEY_TOO_LARGE); | |
328 | goto err; | |
329 | } | |
330 | memcpy(private_bytes, priv->d, todo); | |
331 | memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); | |
332 | ||
333 | for (done = 0; done < num_k_bytes;) { | |
334 | if (RAND_bytes(random_bytes, sizeof(random_bytes)) != 1) | |
335 | goto err; | |
336 | SHA512_Init(&sha); | |
337 | SHA512_Update(&sha, &done, sizeof(done)); | |
338 | SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); | |
339 | SHA512_Update(&sha, message, message_len); | |
340 | SHA512_Update(&sha, random_bytes, sizeof(random_bytes)); | |
341 | SHA512_Final(digest, &sha); | |
342 | ||
343 | todo = num_k_bytes - done; | |
344 | if (todo > SHA512_DIGEST_LENGTH) | |
345 | todo = SHA512_DIGEST_LENGTH; | |
346 | memcpy(k_bytes + done, digest, todo); | |
347 | done += todo; | |
348 | } | |
349 | ||
350 | if (!BN_bin2bn(k_bytes, num_k_bytes, out)) | |
351 | goto err; | |
352 | if (BN_mod(out, out, range, ctx) != 1) | |
353 | goto err; | |
354 | ret = 1; | |
355 | ||
356 | err: | |
357 | if (k_bytes) | |
358 | OPENSSL_free(k_bytes); | |
359 | return ret; | |
360 | } |