/* crypto/bn/bn_rand.c */

 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

  * All rights reserved.

  *

  * This package is an SSL implementation written

  * by Eric Young (eay@cryptsoft.com).

  * The implementation was written so as to conform with Netscapes SSL.

  * 

  * This library is free for commercial and non-commercial use as long as

  * the following conditions are aheared to.  The following conditions

  * apply to all code found in this distribution, be it the RC4, RSA,

  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

  * included with this distribution is covered by the same copyright terms

  * except that the holder is Tim Hudson (tjh@cryptsoft.com).

  * 

  * Copyright remains Eric Young's, and as such any Copyright notices in

  * the code are not to be removed.

  * If this package is used in a product, Eric Young should be given attribution

  * as the author of the parts of the library used.

  * This can be in the form of a textual message at program startup or

  * in documentation (online or textual) provided with the package.

  * 

  * 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 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.

  * 3. All advertising materials mentioning features or use of this software

  *    must display the following acknowledgement:

  *    "This product includes cryptographic software written by

  *     Eric Young (eay@cryptsoft.com)"

  *    The word 'cryptographic' can be left out if the rouines from the library

  *    being used are not cryptographic related :-).

  * 4. If you include any Windows specific code (or a derivative thereof) from 

  *    the apps directory (application code) you must include an acknowledgement:

  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

  * 

  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 OR CONTRIBUTORS 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.

  * 

  * The licence and distribution terms for any publically available version or

  * derivative of this code cannot be changed.  i.e. this code cannot simply be

  * copied and put under another distribution licence

  * [including the GNU Public Licence.]

  */

 /* ====================================================================

  * Copyright (c) 1998-2001 The OpenSSL Project.  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.

  *

  * 3. All advertising materials mentioning features or use of this

  *    software must display the following acknowledgment:

  *    "This product includes software developed by the OpenSSL Project

  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

  *

  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

  *    endorse or promote products derived from this software without

  *    prior written permission. For written permission, please contact

  *    openssl-core@openssl.org.

  *

  * 5. Products derived from this software may not be called "OpenSSL"

  *    nor may "OpenSSL" appear in their names without prior written

  *    permission of the OpenSSL Project.

  *

  * 6. Redistributions of any form whatsoever must retain the following

  *    acknowledgment:

  *    "This product includes software developed by the OpenSSL Project

  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

  *

  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

  * EXPRESSED 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 OpenSSL PROJECT OR

  * ITS CONTRIBUTORS 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.

  * ====================================================================

  *

  * This product includes cryptographic software written by Eric Young

  * (eay@cryptsoft.com).  This product includes software written by Tim

  * Hudson (tjh@cryptsoft.com).

  *

  */

 #include <stdio.h>

 #include <time.h>

 #include "cryptlib.h"

 #include "bn_lcl.h"

 #include <openssl/rand.h>

 static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)

 	{

 	unsigned char *buf=NULL;

 	int ret=0,bit,bytes,mask;

 	time_t tim;

 	if (bits == 0)

 		{

 		BN_zero(rnd);

 		return 1;

 		}

 	bytes=(bits+7)/8;

 	bit=(bits-1)%8;

 	mask=0xff<<(bit+1);

 	buf=(unsigned char *)OPENSSL_malloc(bytes);

 	if (buf == NULL)

 		{

 		BNerr(BN_F_BNRAND,ERR_R_MALLOC_FAILURE);

 		goto err;

 		}

 	/* make a random number and set the top and bottom bits */

 	time(&tim);

 	RAND_add(&tim,sizeof(tim),0.0);

 	if (pseudorand)

 		{

 		if (RAND_pseudo_bytes(buf, bytes) == -1)

 			goto err;

 		}

 	else

 		{

 		if (RAND_bytes(buf, bytes) <= 0)

 			goto err;

 		}

 #if 1

 	if (pseudorand == 2)

 		{

 		/* generate patterns that are more likely to trigger BN

 		   library bugs */

 		int i;

 		unsigned char c;

 		for (i = 0; i < bytes; i++)

 			{

 			RAND_pseudo_bytes(&c, 1);

 			if (c >= 128 && i > 0)

 				buf[i] = buf[i-1];

 			else if (c < 42)

 				buf[i] = 0;

 			else if (c < 84)

 				buf[i] = 255;

 			}

 		}

 #endif

 	if (top != -1)

 		{

 		if (top)

 			{

 			if (bit == 0)

 				{

 				buf[0]=1;

 				buf[1]|=0x80;

 				}

 			else

 				{

 				buf[0]|=(3<<(bit-1));

 				}

 			}

 		else

 			{

 			buf[0]|=(1<<bit);

 			}

 		}

 	buf[0] &= ~mask;

 	if (bottom) /* set bottom bit if requested */

 		buf[bytes-1]|=1;

 	if (!BN_bin2bn(buf,bytes,rnd)) goto err;

 	ret=1;

 err:

 	if (buf != NULL)

 		{

 		OPENSSL_cleanse(buf,bytes);

 		OPENSSL_free(buf);

 		}

 	bn_check_top(rnd);

 	return(ret);

 	}

 EXPORT_C int     BN_rand(BIGNUM *rnd, int bits, int top, int bottom)

 	{

 	return bnrand(0, rnd, bits, top, bottom);

 	}

 EXPORT_C int     BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)

 	{

 	return bnrand(1, rnd, bits, top, bottom);

 	}

 #if 1

 EXPORT_C int     BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom)

 	{

 	return bnrand(2, rnd, bits, top, bottom);

 	}

 #endif

 /* random number r:  0 <= r < range */

 static int bn_rand_range(int pseudo, BIGNUM *r, BIGNUM *range)

 	{

 	int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand;

 	int n;

 	int count = 100;

 	if (range->neg || BN_is_zero(range))

 		{

 		BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);

 		return 0;

 		}

 	n = BN_num_bits(range); /* n > 0 */

 	/* BN_is_bit_set(range, n - 1) always holds */

 	if (n == 1)

 		BN_zero(r);

 	else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3))

 		{

 		/* range = 100..._2,

 		 * so  3*range (= 11..._2)  is exactly one bit longer than  range */

 		do

 			{

 			if (!bn_rand(r, n + 1, -1, 0)) return 0;

 			/* If  r < 3*range,  use  r := r MOD range

 			 * (which is either  r, r - range,  or  r - 2*range).

 			 * Otherwise, iterate once more.

 			 * Since  3*range = 11..._2, each iteration succeeds with

 			 * probability >= .75. */

 			if (BN_cmp(r ,range) >= 0)

 				{

 				if (!BN_sub(r, r, range)) return 0;

 				if (BN_cmp(r, range) >= 0)

 					if (!BN_sub(r, r, range)) return 0;

 				}

 			if (!--count)

 				{

 				BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);

 				return 0;

 				}

 			}

 		while (BN_cmp(r, range) >= 0);

 		}

 	else

 		{

 		do

 			{

 			/* range = 11..._2  or  range = 101..._2 */

 			if (!bn_rand(r, n, -1, 0)) return 0;

 			if (!--count)

 				{

 				BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS);

 				return 0;

 				}

 			}

 		while (BN_cmp(r, range) >= 0);

 		}

 	bn_check_top(r);

 	return 1;

 	}

 EXPORT_C int	BN_rand_range(BIGNUM *r, BIGNUM *range)

 	{

 	return bn_rand_range(0, r, range);

 	}

 EXPORT_C int	BN_pseudo_rand_range(BIGNUM *r, BIGNUM *range)

 	{

 	return bn_rand_range(1, r, range);

 	}