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1 /* crypto/bn/bn_rand.c */ | |
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
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. | |
8 * | |
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). | |
15 * | |
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. | |
22 * | |
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 :-). | |
37 * 4. If you include any Windows specific code (or a derivative thereof) from | |
38 * the apps directory (application code) you must include an acknowledgement: | |
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
40 * | |
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. | |
52 * | |
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 */ | |
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 | |
66 * notice, this list of conditions and the following disclaimer. | |
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 */ | |
111 | |
112 #include <stdio.h> | |
113 #include <time.h> | |
114 #include "cryptlib.h" | |
115 #include "bn_lcl.h" | |
116 #include <openssl/rand.h> | |
117 | |
118 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom) | |
119 { | |
120 unsigned char *buf=NULL; | |
121 int ret=0,bit,bytes,mask; | |
122 time_t tim; | |
123 | |
124 if (bits == 0) | |
125 { | |
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 { | |
137 BNerr(BN_F_BNRAND,ERR_R_MALLOC_FAILURE); | |
138 goto err; | |
139 } | |
140 | |
141 /* make a random number and set the top and bottom bits */ | |
142 time(&tim); | |
143 RAND_add(&tim,sizeof(tim),0.0); | |
144 | |
145 if (pseudorand) | |
146 { | |
147 if (RAND_pseudo_bytes(buf, bytes) == -1) | |
148 goto err; | |
149 } | |
150 else | |
151 { | |
152 if (RAND_bytes(buf, bytes) <= 0) | |
153 goto err; | |
154 } | |
155 | |
156 #if 1 | |
157 if (pseudorand == 2) | |
158 { | |
159 /* generate patterns that are more likely to trigger BN | |
160 library bugs */ | |
161 int i; | |
162 unsigned char c; | |
163 | |
164 for (i = 0; i < bytes; i++) | |
165 { | |
166 RAND_pseudo_bytes(&c, 1); | |
167 if (c >= 128 && i > 0) | |
168 buf[i] = buf[i-1]; | |
169 else if (c < 42) | |
170 buf[i] = 0; | |
171 else if (c < 84) | |
172 buf[i] = 255; | |
173 } | |
174 } | |
175 #endif | |
176 | |
177 if (top != -1) | |
178 { | |
179 if (top) | |
180 { | |
181 if (bit == 0) | |
182 { | |
183 buf[0]=1; | |
184 buf[1]|=0x80; | |
185 } | |
186 else | |
187 { | |
188 buf[0]|=(3<<(bit-1)); | |
189 } | |
190 } | |
191 else | |
192 { | |
193 buf[0]|=(1<<bit); | |
194 } | |
195 } | |
196 buf[0] &= ~mask; | |
197 if (bottom) /* set bottom bit if requested */ | |
198 buf[bytes-1]|=1; | |
199 if (!BN_bin2bn(buf,bytes,rnd)) goto err; | |
200 ret=1; | |
201 err: | |
202 if (buf != NULL) | |
203 { | |
204 OPENSSL_cleanse(buf,bytes); | |
205 OPENSSL_free(buf); | |
206 } | |
207 bn_check_top(rnd); | |
208 return(ret); | |
209 } | |
210 | |
211 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
212 { | |
213 return bnrand(0, rnd, bits, top, bottom); | |
214 } | |
215 | |
216 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
217 { | |
218 return bnrand(1, rnd, bits, top, bottom); | |
219 } | |
220 | |
221 #if 1 | |
222 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) | |
223 { | |
224 return bnrand(2, rnd, bits, top, bottom); | |
225 } | |
226 #endif | |
227 | |
228 | |
229 /* random number r: 0 <= r < range */ | |
230 static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) | |
231 { | |
232 int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_r
and; | |
233 int n; | |
234 int count = 100; | |
235 | |
236 if (range->neg || BN_is_zero(range)) | |
237 { | |
238 BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); | |
239 return 0; | |
240 } | |
241 | |
242 n = BN_num_bits(range); /* n > 0 */ | |
243 | |
244 /* BN_is_bit_set(range, n - 1) always holds */ | |
245 | |
246 if (n == 1) | |
247 BN_zero(r); | |
248 else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) | |
249 { | |
250 /* range = 100..._2, | |
251 * so 3*range (= 11..._2) is exactly one bit longer than rang
e */ | |
252 do | |
253 { | |
254 if (!bn_rand(r, n + 1, -1, 0)) return 0; | |
255 /* If r < 3*range, use r := r MOD range | |
256 * (which is either r, r - range, or r - 2*range). | |
257 * Otherwise, iterate once more. | |
258 * Since 3*range = 11..._2, each iteration succeeds wit
h | |
259 * probability >= .75. */ | |
260 if (BN_cmp(r ,range) >= 0) | |
261 { | |
262 if (!BN_sub(r, r, range)) return 0; | |
263 if (BN_cmp(r, range) >= 0) | |
264 if (!BN_sub(r, r, range)) return 0; | |
265 } | |
266 | |
267 if (!--count) | |
268 { | |
269 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIO
NS); | |
270 return 0; | |
271 } | |
272 | |
273 } | |
274 while (BN_cmp(r, range) >= 0); | |
275 } | |
276 else | |
277 { | |
278 do | |
279 { | |
280 /* range = 11..._2 or range = 101..._2 */ | |
281 if (!bn_rand(r, n, -1, 0)) return 0; | |
282 | |
283 if (!--count) | |
284 { | |
285 BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIO
NS); | |
286 return 0; | |
287 } | |
288 } | |
289 while (BN_cmp(r, range) >= 0); | |
290 } | |
291 | |
292 bn_check_top(r); | |
293 return 1; | |
294 } | |
295 | |
296 | |
297 int BN_rand_range(BIGNUM *r, const BIGNUM *range) | |
298 { | |
299 return bn_rand_range(0, r, range); | |
300 } | |
301 | |
302 int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) | |
303 { | |
304 return bn_rand_range(1, r, range); | |
305 } | |
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