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
bnrand(int pseudorand,BIGNUM * rnd,int bits,int top,int bottom)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
123 if (bits == 0)
124 {
125 BN_zero(rnd);
126 return 1;
127 }
128
129 bytes=(bits+7)/8;
130 bit=(bits-1)%8;
131 mask=0xff<<(bit+1);
132
133 buf=(unsigned char *)OPENSSL_malloc(bytes);
134 if (buf == NULL)
135 {
136 BNerr(BN_F_BN_RAND,ERR_R_MALLOC_FAILURE);
137 goto err;
138 }
139
140 /* make a random number and set the top and bottom bits */
141 RAND_add(NULL, 0, 0);
142
143 if (pseudorand)
144 {
145 if (RAND_pseudo_bytes(buf, bytes) == -1)
146 goto err;
147 }
148 else
149 {
150 if (RAND_bytes(buf, bytes) <= 0)
151 goto err;
152 }
153
154 #if 1
155 if (pseudorand == 2)
156 {
157 /* generate patterns that are more likely to trigger BN
158 library bugs */
159 int i;
160 unsigned char c;
161
162 for (i = 0; i < bytes; i++)
163 {
164 RAND_pseudo_bytes(&c, 1);
165 if (c >= 128 && i > 0)
166 buf[i] = buf[i-1];
167 else if (c < 42)
168 buf[i] = 0;
169 else if (c < 84)
170 buf[i] = 255;
171 }
172 }
173 #endif
174
175 if (top != -1)
176 {
177 if (top)
178 {
179 if (bit == 0)
180 {
181 buf[0]=1;
182 buf[1]|=0x80;
183 }
184 else
185 {
186 buf[0]|=(3<<(bit-1));
187 }
188 }
189 else
190 {
191 buf[0]|=(1<<bit);
192 }
193 }
194 buf[0] &= ~mask;
195 if (bottom) /* set bottom bit if requested */
196 buf[bytes-1]|=1;
197 if (!BN_bin2bn(buf,bytes,rnd)) goto err;
198 ret=1;
199 err:
200 if (buf != NULL)
201 {
202 OPENSSL_cleanse(buf,bytes);
203 OPENSSL_free(buf);
204 }
205 return(ret);
206 }
207
BN_rand(BIGNUM * rnd,int bits,int top,int bottom)208 int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
209 {
210 return bnrand(0, rnd, bits, top, bottom);
211 }
212
BN_pseudo_rand(BIGNUM * rnd,int bits,int top,int bottom)213 int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
214 {
215 return bnrand(1, rnd, bits, top, bottom);
216 }
217
218 #if 1
BN_bntest_rand(BIGNUM * rnd,int bits,int top,int bottom)219 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)
220 {
221 return bnrand(2, rnd, bits, top, bottom);
222 }
223 #endif
224
225
226 /* random number r: 0 <= r < range */
bn_rand_range(int pseudo,BIGNUM * r,BIGNUM * range)227 static int bn_rand_range(int pseudo, BIGNUM *r, BIGNUM *range)
228 {
229 int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand;
230 int n;
231
232 if (range->neg || BN_is_zero(range))
233 {
234 BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
235 return 0;
236 }
237
238 n = BN_num_bits(range); /* n > 0 */
239
240 /* BN_is_bit_set(range, n - 1) always holds */
241
242 if (n == 1)
243 {
244 if (!BN_zero(r)) return 0;
245 }
246 else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3))
247 {
248 /* range = 100..._2,
249 * so 3*range (= 11..._2) is exactly one bit longer than range */
250 do
251 {
252 if (!bn_rand(r, n + 1, -1, 0)) return 0;
253 /* If r < 3*range, use r := r MOD range
254 * (which is either r, r - range, or r - 2*range).
255 * Otherwise, iterate once more.
256 * Since 3*range = 11..._2, each iteration succeeds with
257 * probability >= .75. */
258 if (BN_cmp(r ,range) >= 0)
259 {
260 if (!BN_sub(r, r, range)) return 0;
261 if (BN_cmp(r, range) >= 0)
262 if (!BN_sub(r, r, range)) return 0;
263 }
264 }
265 while (BN_cmp(r, range) >= 0);
266 }
267 else
268 {
269 do
270 {
271 /* range = 11..._2 or range = 101..._2 */
272 if (!bn_rand(r, n, -1, 0)) return 0;
273 }
274 while (BN_cmp(r, range) >= 0);
275 }
276
277 return 1;
278 }
279
280
BN_rand_range(BIGNUM * r,BIGNUM * range)281 int BN_rand_range(BIGNUM *r, BIGNUM *range)
282 {
283 return bn_rand_range(0, r, range);
284 }
285
BN_pseudo_rand_range(BIGNUM * r,BIGNUM * range)286 int BN_pseudo_rand_range(BIGNUM *r, BIGNUM *range)
287 {
288 return bn_rand_range(1, r, range);
289 }
290