--- /dev/null
+/* 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 <openssl/bn.h>
+
+#include <string.h>
+
+#include <openssl/err.h>
+#include <openssl/mem.h>
+#include <openssl/rand.h>
+#include <openssl/type_check.h>
+
+#include "internal.h"
+#include "../../internal.h"
+#include "../rand/internal.h"
+
+
+int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) {
+ uint8_t *buf = NULL;
+ int ret = 0, bit, bytes, mask;
+
+ if (rnd == NULL) {
+ return 0;
+ }
+
+ if (top != BN_RAND_TOP_ANY && top != BN_RAND_TOP_ONE &&
+ top != BN_RAND_TOP_TWO) {
+ OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
+ return 0;
+ }
+
+ if (bottom != BN_RAND_BOTTOM_ANY && bottom != BN_RAND_BOTTOM_ODD) {
+ OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
+ return 0;
+ }
+
+ if (bits == 0) {
+ BN_zero(rnd);
+ return 1;
+ }
+
+ bytes = (bits + 7) / 8;
+ bit = (bits - 1) % 8;
+ mask = 0xff << (bit + 1);
+
+ buf = OPENSSL_malloc(bytes);
+ if (buf == NULL) {
+ OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ // Make a random number and set the top and bottom bits.
+ RAND_bytes(buf, bytes);
+
+ if (top != BN_RAND_TOP_ANY) {
+ if (top == BN_RAND_TOP_TWO && bits > 1) {
+ if (bit == 0) {
+ buf[0] = 1;
+ buf[1] |= 0x80;
+ } else {
+ buf[0] |= (3 << (bit - 1));
+ }
+ } else {
+ buf[0] |= (1 << bit);
+ }
+ }
+
+ buf[0] &= ~mask;
+
+ // Set the bottom bit if requested,
+ if (bottom == BN_RAND_BOTTOM_ODD) {
+ buf[bytes - 1] |= 1;
+ }
+
+ if (!BN_bin2bn(buf, bytes, rnd)) {
+ goto err;
+ }
+
+ ret = 1;
+
+err:
+ OPENSSL_free(buf);
+ return ret;
+}
+
+int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) {
+ return BN_rand(rnd, bits, top, bottom);
+}
+
+// bn_less_than_word_mask returns a mask of all ones if the number represented
+// by |len| words at |a| is less than |b| and zero otherwise. It performs this
+// computation in time independent of the value of |a|. |b| is assumed public.
+static crypto_word_t bn_less_than_word_mask(const BN_ULONG *a, size_t len,
+ BN_ULONG b) {
+ if (b == 0) {
+ return CONSTTIME_FALSE_W;
+ }
+ if (len == 0) {
+ return CONSTTIME_TRUE_W;
+ }
+
+ // |a| < |b| iff a[1..len-1] are all zero and a[0] < b.
+ OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small);
+ crypto_word_t mask = 0;
+ for (size_t i = 1; i < len; i++) {
+ mask |= a[i];
+ }
+ // |mask| is now zero iff a[1..len-1] are all zero.
+ mask = constant_time_is_zero_w(mask);
+ mask &= constant_time_lt_w(a[0], b);
+ return mask;
+}
+
+int bn_in_range_words(const BN_ULONG *a, BN_ULONG min_inclusive,
+ const BN_ULONG *max_exclusive, size_t len) {
+ crypto_word_t mask = ~bn_less_than_word_mask(a, len, min_inclusive);
+ return mask & bn_less_than_words(a, max_exclusive, len);
+}
+
+static int bn_range_to_mask(size_t *out_words, BN_ULONG *out_mask,
+ size_t min_inclusive, const BN_ULONG *max_exclusive,
+ size_t len) {
+ // The magnitude of |max_exclusive| is assumed public.
+ size_t words = len;
+ while (words > 0 && max_exclusive[words - 1] == 0) {
+ words--;
+ }
+ if (words == 0 ||
+ (words == 1 && max_exclusive[0] <= min_inclusive)) {
+ OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE);
+ return 0;
+ }
+ BN_ULONG mask = max_exclusive[words - 1];
+ // This sets all bits in |mask| below the most significant bit.
+ mask |= mask >> 1;
+ mask |= mask >> 2;
+ mask |= mask >> 4;
+ mask |= mask >> 8;
+ mask |= mask >> 16;
+#if defined(OPENSSL_64_BIT)
+ mask |= mask >> 32;
+#endif
+
+ *out_words = words;
+ *out_mask = mask;
+ return 1;
+}
+
+int bn_rand_range_words(BN_ULONG *out, BN_ULONG min_inclusive,
+ const BN_ULONG *max_exclusive, size_t len,
+ const uint8_t additional_data[32]) {
+ // This function implements the equivalent of steps 4 through 7 of FIPS 186-4
+ // appendices B.4.2 and B.5.2. When called in those contexts, |max_exclusive|
+ // is n and |min_inclusive| is one.
+
+ // Compute the bit length of |max_exclusive| (step 1), in terms of a number of
+ // |words| worth of entropy to fill and a mask of bits to clear in the top
+ // word.
+ size_t words;
+ BN_ULONG mask;
+ if (!bn_range_to_mask(&words, &mask, min_inclusive, max_exclusive, len)) {
+ return 0;
+ }
+
+ // Fill any unused words with zero.
+ OPENSSL_memset(out + words, 0, (len - words) * sizeof(BN_ULONG));
+
+ unsigned count = 100;
+ do {
+ if (!--count) {
+ OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS);
+ return 0;
+ }
+
+ // Steps 4 and 5. Use |words| and |mask| together to obtain a string of N
+ // bits, where N is the bit length of |max_exclusive|.
+ RAND_bytes_with_additional_data((uint8_t *)out, words * sizeof(BN_ULONG),
+ additional_data);
+ out[words - 1] &= mask;
+
+ // If out >= max_exclusive or out < min_inclusive, retry. This implements
+ // the equivalent of steps 6 and 7 without leaking the value of |out|.
+ } while (!bn_in_range_words(out, min_inclusive, max_exclusive, words));
+ return 1;
+}
+
+int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
+ const BIGNUM *max_exclusive) {
+ static const uint8_t kDefaultAdditionalData[32] = {0};
+ if (!bn_wexpand(r, max_exclusive->width) ||
+ !bn_rand_range_words(r->d, min_inclusive, max_exclusive->d,
+ max_exclusive->width, kDefaultAdditionalData)) {
+ return 0;
+ }
+
+ r->neg = 0;
+ r->width = max_exclusive->width;
+ return 1;
+}
+
+int bn_rand_secret_range(BIGNUM *r, int *out_is_uniform, BN_ULONG min_inclusive,
+ const BIGNUM *max_exclusive) {
+ size_t words;
+ BN_ULONG mask;
+ if (!bn_range_to_mask(&words, &mask, min_inclusive, max_exclusive->d,
+ max_exclusive->width) ||
+ !bn_wexpand(r, words)) {
+ return 0;
+ }
+
+ assert(words > 0);
+ assert(mask != 0);
+ // The range must be large enough for bit tricks to fix invalid values.
+ if (words == 1 && min_inclusive > mask >> 1) {
+ OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE);
+ return 0;
+ }
+
+ // Select a uniform random number with num_bits(max_exclusive) bits.
+ RAND_bytes((uint8_t *)r->d, words * sizeof(BN_ULONG));
+ r->d[words - 1] &= mask;
+
+ // Check, in constant-time, if the value is in range.
+ *out_is_uniform =
+ bn_in_range_words(r->d, min_inclusive, max_exclusive->d, words);
+ crypto_word_t in_range = *out_is_uniform;
+ in_range = 0 - in_range;
+
+ // If the value is not in range, force it to be in range.
+ r->d[0] |= constant_time_select_w(in_range, 0, min_inclusive);
+ r->d[words - 1] &= constant_time_select_w(in_range, BN_MASK2, mask >> 1);
+ assert(bn_in_range_words(r->d, min_inclusive, max_exclusive->d, words));
+
+ r->neg = 0;
+ r->width = words;
+ return 1;
+}
+
+int BN_rand_range(BIGNUM *r, const BIGNUM *range) {
+ return BN_rand_range_ex(r, 0, range);
+}
+
+int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) {
+ return BN_rand_range(r, range);
+}
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