--- /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.] */
+
+#include <openssl/bn.h>
+
+#include <openssl/mem.h>
+#include <openssl/type_check.h>
+
+#include "internal.h"
+#include "../../internal.h"
+
+
+static int bn_cmp_words_consttime(const BN_ULONG *a, size_t a_len,
+ const BN_ULONG *b, size_t b_len) {
+ OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small);
+ int ret = 0;
+ // Process the common words in little-endian order.
+ size_t min = a_len < b_len ? a_len : b_len;
+ for (size_t i = 0; i < min; i++) {
+ crypto_word_t eq = constant_time_eq_w(a[i], b[i]);
+ crypto_word_t lt = constant_time_lt_w(a[i], b[i]);
+ ret =
+ constant_time_select_int(eq, ret, constant_time_select_int(lt, -1, 1));
+ }
+
+ // If |a| or |b| has non-zero words beyond |min|, they take precedence.
+ if (a_len < b_len) {
+ crypto_word_t mask = 0;
+ for (size_t i = a_len; i < b_len; i++) {
+ mask |= b[i];
+ }
+ ret = constant_time_select_int(constant_time_is_zero_w(mask), ret, -1);
+ } else if (b_len < a_len) {
+ crypto_word_t mask = 0;
+ for (size_t i = b_len; i < a_len; i++) {
+ mask |= a[i];
+ }
+ ret = constant_time_select_int(constant_time_is_zero_w(mask), ret, 1);
+ }
+
+ return ret;
+}
+
+int BN_ucmp(const BIGNUM *a, const BIGNUM *b) {
+ return bn_cmp_words_consttime(a->d, a->width, b->d, b->width);
+}
+
+int BN_cmp(const BIGNUM *a, const BIGNUM *b) {
+ if ((a == NULL) || (b == NULL)) {
+ if (a != NULL) {
+ return -1;
+ } else if (b != NULL) {
+ return 1;
+ } else {
+ return 0;
+ }
+ }
+
+ // We do not attempt to process the sign bit in constant time. Negative
+ // |BIGNUM|s should never occur in crypto, only calculators.
+ if (a->neg != b->neg) {
+ if (a->neg) {
+ return -1;
+ }
+ return 1;
+ }
+
+ int ret = BN_ucmp(a, b);
+ return a->neg ? -ret : ret;
+}
+
+int bn_less_than_words(const BN_ULONG *a, const BN_ULONG *b, size_t len) {
+ return bn_cmp_words_consttime(a, len, b, len) < 0;
+}
+
+int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w) {
+ if (bn->width == 0) {
+ return w == 0;
+ }
+ BN_ULONG mask = bn->d[0] ^ w;
+ for (int i = 1; i < bn->width; i++) {
+ mask |= bn->d[i];
+ }
+ return mask == 0;
+}
+
+int BN_cmp_word(const BIGNUM *a, BN_ULONG b) {
+ BIGNUM b_bn;
+ BN_init(&b_bn);
+
+ b_bn.d = &b;
+ b_bn.width = b > 0;
+ b_bn.dmax = 1;
+ b_bn.flags = BN_FLG_STATIC_DATA;
+ return BN_cmp(a, &b_bn);
+}
+
+int BN_is_zero(const BIGNUM *bn) {
+ return bn_fits_in_words(bn, 0);
+}
+
+int BN_is_one(const BIGNUM *bn) {
+ return bn->neg == 0 && BN_abs_is_word(bn, 1);
+}
+
+int BN_is_word(const BIGNUM *bn, BN_ULONG w) {
+ return BN_abs_is_word(bn, w) && (w == 0 || bn->neg == 0);
+}
+
+int BN_is_odd(const BIGNUM *bn) {
+ return bn->width > 0 && (bn->d[0] & 1) == 1;
+}
+
+int BN_is_pow2(const BIGNUM *bn) {
+ int width = bn_minimal_width(bn);
+ if (width == 0 || bn->neg) {
+ return 0;
+ }
+
+ for (int i = 0; i < width - 1; i++) {
+ if (bn->d[i] != 0) {
+ return 0;
+ }
+ }
+
+ return 0 == (bn->d[width-1] & (bn->d[width-1] - 1));
+}
+
+int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b) {
+ BN_ULONG mask = 0;
+ // If |a| or |b| has more words than the other, all those words must be zero.
+ for (int i = a->width; i < b->width; i++) {
+ mask |= b->d[i];
+ }
+ for (int i = b->width; i < a->width; i++) {
+ mask |= a->d[i];
+ }
+ // Common words must match.
+ int min = a->width < b->width ? a->width : b->width;
+ for (int i = 0; i < min; i++) {
+ mask |= (a->d[i] ^ b->d[i]);
+ }
+ // The sign bit must match.
+ mask |= (a->neg ^ b->neg);
+ return mask == 0;
+}
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