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