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+/* 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);
+ }
+
+int BN_rand(BIGNUM *rnd, int bits, int top, int bottom)
+ {
+ return bnrand(0, rnd, bits, top, bottom);
+ }
+
+int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
+ {
+ return bnrand(1, rnd, bits, top, bottom);
+ }
+
+#if 1
+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, const 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;
+ }
+
+
+int BN_rand_range(BIGNUM *r, const BIGNUM *range)
+ {
+ return bn_rand_range(0, r, range);
+ }
+
+int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range)
+ {
+ return bn_rand_range(1, r, range);
+ }