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git.ipfire.org Git - thirdparty/openssl.git/blob - crypto/bn/bn_rand.c
1 /* crypto/bn/bn_rand.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
58 /* ====================================================================
59 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
87 * 6. Redistributions of any form whatsoever must retain the following
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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 * ====================================================================
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).
114 #include "cryptlib.h"
116 #include <openssl/rand.h>
118 static int bnrand(int pseudorand
, BIGNUM
*rnd
, int bits
, int top
, int bottom
)
120 unsigned char *buf
=NULL
;
121 int ret
=0,bit
,bytes
,mask
;
134 buf
=(unsigned char *)OPENSSL_malloc(bytes
);
137 BNerr(BN_F_BN_RAND
,ERR_R_MALLOC_FAILURE
);
141 /* make a random number and set the top and bottom bits */
143 RAND_add(&tim
,sizeof(tim
),0);
147 if (RAND_pseudo_bytes(buf
, bytes
) == -1)
152 if (RAND_bytes(buf
, bytes
) <= 0)
159 /* generate patterns that are more likely to trigger BN
164 for (i
= 0; i
< bytes
; i
++)
166 RAND_pseudo_bytes(&c
, 1);
167 if (c
>= 128 && i
> 0)
188 buf
[0]|=(3<<(bit
-1));
197 if (bottom
) /* set bottom bit if requested */
199 if (!BN_bin2bn(buf
,bytes
,rnd
)) goto err
;
204 OPENSSL_cleanse(buf
,bytes
);
211 int BN_rand(BIGNUM
*rnd
, int bits
, int top
, int bottom
)
213 return bnrand(0, rnd
, bits
, top
, bottom
);
216 int BN_pseudo_rand(BIGNUM
*rnd
, int bits
, int top
, int bottom
)
218 return bnrand(1, rnd
, bits
, top
, bottom
);
222 int BN_bntest_rand(BIGNUM
*rnd
, int bits
, int top
, int bottom
)
224 return bnrand(2, rnd
, bits
, top
, bottom
);
229 /* random number r: 0 <= r < range */
230 static int bn_rand_range(int pseudo
, BIGNUM
*r
, BIGNUM
*range
)
232 int (*bn_rand
)(BIGNUM
*, int, int, int) = pseudo
? BN_pseudo_rand
: BN_rand
;
236 if (range
->neg
|| BN_is_zero(range
))
238 BNerr(BN_F_BN_RAND_RANGE
, BN_R_INVALID_RANGE
);
242 n
= BN_num_bits(range
); /* n > 0 */
244 /* BN_is_bit_set(range, n - 1) always holds */
248 if (!BN_zero(r
)) return 0;
250 else if (!BN_is_bit_set(range
, n
- 2) && !BN_is_bit_set(range
, n
- 3))
253 * so 3*range (= 11..._2) is exactly one bit longer than range */
256 if (!bn_rand(r
, n
+ 1, -1, 0)) return 0;
257 /* If r < 3*range, use r := r MOD range
258 * (which is either r, r - range, or r - 2*range).
259 * Otherwise, iterate once more.
260 * Since 3*range = 11..._2, each iteration succeeds with
261 * probability >= .75. */
262 if (BN_cmp(r
,range
) >= 0)
264 if (!BN_sub(r
, r
, range
)) return 0;
265 if (BN_cmp(r
, range
) >= 0)
266 if (!BN_sub(r
, r
, range
)) return 0;
271 BNerr(BN_F_BN_RAND_RANGE
, BN_R_TOO_MANY_ITERATIONS
);
276 while (BN_cmp(r
, range
) >= 0);
282 /* range = 11..._2 or range = 101..._2 */
283 if (!bn_rand(r
, n
, -1, 0)) return 0;
287 BNerr(BN_F_BN_RAND_RANGE
, BN_R_TOO_MANY_ITERATIONS
);
291 while (BN_cmp(r
, range
) >= 0);
299 int BN_rand_range(BIGNUM
*r
, BIGNUM
*range
)
301 return bn_rand_range(0, r
, range
);
304 int BN_pseudo_rand_range(BIGNUM
*r
, BIGNUM
*range
)
306 return bn_rand_range(1, r
, range
);