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Damien Miller11fa2cc2000-08-16 10:35:58 +10001/*
2 * Copyright (c) 1999-2000 Damien Miller. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
Damien Miller11fa2cc2000-08-16 10:35:58 +100012 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
Damien Miller11fa2cc2000-08-16 10:35:58 +100026
27#ifndef HAVE_ARC4RANDOM
28
Damien Miller72c9a7e2000-09-24 11:10:13 +110029#include <openssl/rand.h>
30#include <openssl/rc4.h>
31
Damien Millerc30d35c2000-08-30 09:40:09 +110032/* Size of key to use */
33#define SEED_SIZE 20
34
35/* Number of bytes to reseed after */
Damien Miller656d7172000-10-27 09:27:32 +110036#define REKEY_BYTES (1 << 24)
Damien Millerc30d35c2000-08-30 09:40:09 +110037
Damien Miller11fa2cc2000-08-16 10:35:58 +100038static int rc4_ready = 0;
39static RC4_KEY rc4;
40
41unsigned int arc4random(void)
42{
43 unsigned int r = 0;
44
Damien Millerc30d35c2000-08-30 09:40:09 +110045 if (rc4_ready <= 0)
Damien Miller11fa2cc2000-08-16 10:35:58 +100046 arc4random_stir();
47
48 RC4(&rc4, sizeof(r), (unsigned char *)&r, (unsigned char *)&r);
Damien Millerc30d35c2000-08-30 09:40:09 +110049
50 rc4_ready -= sizeof(r);
Damien Miller11fa2cc2000-08-16 10:35:58 +100051
52 return(r);
53}
54
55void arc4random_stir(void)
56{
Damien Millerc30d35c2000-08-30 09:40:09 +110057 unsigned char rand_buf[SEED_SIZE];
Damien Miller11fa2cc2000-08-16 10:35:58 +100058
59 memset(&rc4, 0, sizeof(rc4));
60
61 seed_rng();
Damien Millerc30d35c2000-08-30 09:40:09 +110062
Damien Miller11fa2cc2000-08-16 10:35:58 +100063 RAND_bytes(rand_buf, sizeof(rand_buf));
64
65 RC4_set_key(&rc4, sizeof(rand_buf), rand_buf);
66
67 memset(rand_buf, 0, sizeof(rand_buf));
Damien Millerf3df0522000-08-23 15:31:41 +100068
Damien Millerc30d35c2000-08-30 09:40:09 +110069 rc4_ready = REKEY_BYTES;
Damien Miller11fa2cc2000-08-16 10:35:58 +100070}
71#endif /* !HAVE_ARC4RANDOM */