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/*
* Copyright (c) 1999-2000 Damien Miller. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include "log.h"
RCSID("$Id: bsd-arc4random.c,v 1.5 2002/05/08 22:57:18 tim Exp $");
#ifndef HAVE_ARC4RANDOM
#include <openssl/rand.h>
#include <openssl/rc4.h>
#include <openssl/err.h>
/* Size of key to use */
#define SEED_SIZE 20
/* Number of bytes to reseed after */
#define REKEY_BYTES (1 << 24)
static int rc4_ready = 0;
static RC4_KEY rc4;
unsigned int arc4random(void)
{
unsigned int r = 0;
static int first_time = 1;
if (rc4_ready <= 0) {
if (first_time)
seed_rng();
first_time = 0;
arc4random_stir();
}
RC4(&rc4, sizeof(r), (unsigned char *)&r, (unsigned char *)&r);
rc4_ready -= sizeof(r);
return(r);
}
void arc4random_stir(void)
{
unsigned char rand_buf[SEED_SIZE];
memset(&rc4, 0, sizeof(rc4));
if (!RAND_bytes(rand_buf, sizeof(rand_buf)))
fatal("Couldn't obtain random bytes (error %ld)",
ERR_get_error());
RC4_set_key(&rc4, sizeof(rand_buf), rand_buf);
memset(rand_buf, 0, sizeof(rand_buf));
rc4_ready = REKEY_BYTES;
}
#endif /* !HAVE_ARC4RANDOM */
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