--- /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 <string.h>
+
+#include <openssl/err.h>
+#include <openssl/type_check.h>
+
+#include "internal.h"
+
+
+int BN_lshift(BIGNUM *r, const BIGNUM *a, int n) {
+ int i, nw, lb, rb;
+ BN_ULONG *t, *f;
+ BN_ULONG l;
+
+ if (n < 0) {
+ OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
+ return 0;
+ }
+
+ r->neg = a->neg;
+ nw = n / BN_BITS2;
+ if (!bn_wexpand(r, a->width + nw + 1)) {
+ return 0;
+ }
+ lb = n % BN_BITS2;
+ rb = BN_BITS2 - lb;
+ f = a->d;
+ t = r->d;
+ t[a->width + nw] = 0;
+ if (lb == 0) {
+ for (i = a->width - 1; i >= 0; i--) {
+ t[nw + i] = f[i];
+ }
+ } else {
+ for (i = a->width - 1; i >= 0; i--) {
+ l = f[i];
+ t[nw + i + 1] |= l >> rb;
+ t[nw + i] = l << lb;
+ }
+ }
+ OPENSSL_memset(t, 0, nw * sizeof(t[0]));
+ r->width = a->width + nw + 1;
+ bn_set_minimal_width(r);
+
+ return 1;
+}
+
+int BN_lshift1(BIGNUM *r, const BIGNUM *a) {
+ BN_ULONG *ap, *rp, t, c;
+ int i;
+
+ if (r != a) {
+ r->neg = a->neg;
+ if (!bn_wexpand(r, a->width + 1)) {
+ return 0;
+ }
+ r->width = a->width;
+ } else {
+ if (!bn_wexpand(r, a->width + 1)) {
+ return 0;
+ }
+ }
+ ap = a->d;
+ rp = r->d;
+ c = 0;
+ for (i = 0; i < a->width; i++) {
+ t = *(ap++);
+ *(rp++) = (t << 1) | c;
+ c = t >> (BN_BITS2 - 1);
+ }
+ if (c) {
+ *rp = 1;
+ r->width++;
+ }
+
+ return 1;
+}
+
+static void bn_rshift_words(BN_ULONG *r, const BN_ULONG *a, unsigned shift,
+ size_t num) {
+ unsigned shift_bits = shift % BN_BITS2;
+ size_t shift_words = shift / BN_BITS2;
+ if (shift_words >= num) {
+ OPENSSL_memset(r, 0, num * sizeof(BN_ULONG));
+ return;
+ }
+ if (shift_bits == 0) {
+ OPENSSL_memmove(r, a + shift_words, (num - shift_words) * sizeof(BN_ULONG));
+ } else {
+ for (size_t i = shift_words; i < num - 1; i++) {
+ r[i - shift_words] =
+ (a[i] >> shift_bits) | (a[i + 1] << (BN_BITS2 - shift_bits));
+ }
+ r[num - 1 - shift_words] = a[num - 1] >> shift_bits;
+ }
+ OPENSSL_memset(r + num - shift_words, 0, shift_words * sizeof(BN_ULONG));
+}
+
+int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) {
+ if (n < 0) {
+ OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
+ return 0;
+ }
+
+ if (!bn_wexpand(r, a->width)) {
+ return 0;
+ }
+ bn_rshift_words(r->d, a->d, n, a->width);
+ r->neg = a->neg;
+ r->width = a->width;
+ bn_set_minimal_width(r);
+ return 1;
+}
+
+int bn_rshift_secret_shift(BIGNUM *r, const BIGNUM *a, unsigned n,
+ BN_CTX *ctx) {
+ int ret = 0;
+ BN_CTX_start(ctx);
+ BIGNUM *tmp = BN_CTX_get(ctx);
+ if (tmp == NULL ||
+ !BN_copy(r, a) ||
+ !bn_wexpand(tmp, r->width)) {
+ goto err;
+ }
+
+ // Shift conditionally by powers of two.
+ unsigned max_bits = BN_BITS2 * r->width;
+ for (unsigned i = 0; (max_bits >> i) != 0; i++) {
+ BN_ULONG mask = (n >> i) & 1;
+ mask = 0 - mask;
+ bn_rshift_words(tmp->d, r->d, 1u << i, r->width);
+ bn_select_words(r->d, mask, tmp->d /* apply shift */,
+ r->d /* ignore shift */, r->width);
+ }
+
+ ret = 1;
+
+err:
+ BN_CTX_end(ctx);
+ return ret;
+}
+
+void bn_rshift1_words(BN_ULONG *r, const BN_ULONG *a, size_t num) {
+ if (num == 0) {
+ return;
+ }
+ for (size_t i = 0; i < num - 1; i++) {
+ r[i] = (a[i] >> 1) | (a[i + 1] << (BN_BITS2 - 1));
+ }
+ r[num - 1] = a[num - 1] >> 1;
+}
+
+int BN_rshift1(BIGNUM *r, const BIGNUM *a) {
+ if (!bn_wexpand(r, a->width)) {
+ return 0;
+ }
+ bn_rshift1_words(r->d, a->d, a->width);
+ r->width = a->width;
+ r->neg = a->neg;
+ bn_set_minimal_width(r);
+ return 1;
+}
+
+int BN_set_bit(BIGNUM *a, int n) {
+ if (n < 0) {
+ return 0;
+ }
+
+ int i = n / BN_BITS2;
+ int j = n % BN_BITS2;
+ if (a->width <= i) {
+ if (!bn_wexpand(a, i + 1)) {
+ return 0;
+ }
+ for (int k = a->width; k < i + 1; k++) {
+ a->d[k] = 0;
+ }
+ a->width = i + 1;
+ }
+
+ a->d[i] |= (((BN_ULONG)1) << j);
+
+ return 1;
+}
+
+int BN_clear_bit(BIGNUM *a, int n) {
+ int i, j;
+
+ if (n < 0) {
+ return 0;
+ }
+
+ i = n / BN_BITS2;
+ j = n % BN_BITS2;
+ if (a->width <= i) {
+ return 0;
+ }
+
+ a->d[i] &= (~(((BN_ULONG)1) << j));
+ bn_set_minimal_width(a);
+ return 1;
+}
+
+int bn_is_bit_set_words(const BN_ULONG *a, size_t num, unsigned bit) {
+ unsigned i = bit / BN_BITS2;
+ unsigned j = bit % BN_BITS2;
+ if (i >= num) {
+ return 0;
+ }
+ return (a[i] >> j) & 1;
+}
+
+int BN_is_bit_set(const BIGNUM *a, int n) {
+ if (n < 0) {
+ return 0;
+ }
+ return bn_is_bit_set_words(a->d, a->width, n);
+}
+
+int BN_mask_bits(BIGNUM *a, int n) {
+ if (n < 0) {
+ return 0;
+ }
+
+ int w = n / BN_BITS2;
+ int b = n % BN_BITS2;
+ if (w >= a->width) {
+ return 1;
+ }
+ if (b == 0) {
+ a->width = w;
+ } else {
+ a->width = w + 1;
+ a->d[w] &= ~(BN_MASK2 << b);
+ }
+
+ bn_set_minimal_width(a);
+ return 1;
+}
+
+static int bn_count_low_zero_bits_word(BN_ULONG l) {
+ OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small);
+ OPENSSL_COMPILE_ASSERT(sizeof(int) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small_2);
+ OPENSSL_COMPILE_ASSERT(BN_BITS2 == sizeof(BN_ULONG) * 8,
+ bn_ulong_has_padding_bits);
+ // C has very bizarre rules for types smaller than an int.
+ OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) >= sizeof(int),
+ bn_ulong_is_promoted_to_int);
+
+ crypto_word_t mask;
+ int bits = 0;
+
+#if BN_BITS2 > 32
+ // Check if the lower half of |x| are all zero.
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 32));
+ // If the lower half is all zeros, it is included in the bit count and we
+ // count the upper half. Otherwise, we count the lower half.
+ bits += 32 & mask;
+ l = constant_time_select_w(mask, l >> 32, l);
+#endif
+
+ // The remaining blocks are analogous iterations at lower powers of two.
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 16));
+ bits += 16 & mask;
+ l = constant_time_select_w(mask, l >> 16, l);
+
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 8));
+ bits += 8 & mask;
+ l = constant_time_select_w(mask, l >> 8, l);
+
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 4));
+ bits += 4 & mask;
+ l = constant_time_select_w(mask, l >> 4, l);
+
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 2));
+ bits += 2 & mask;
+ l = constant_time_select_w(mask, l >> 2, l);
+
+ mask = constant_time_is_zero_w(l << (BN_BITS2 - 1));
+ bits += 1 & mask;
+
+ return bits;
+}
+
+int BN_count_low_zero_bits(const BIGNUM *bn) {
+ OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small);
+ OPENSSL_COMPILE_ASSERT(sizeof(int) <= sizeof(crypto_word_t),
+ crypto_word_t_too_small_2);
+
+ int ret = 0;
+ crypto_word_t saw_nonzero = 0;
+ for (int i = 0; i < bn->width; i++) {
+ crypto_word_t nonzero = ~constant_time_is_zero_w(bn->d[i]);
+ crypto_word_t first_nonzero = ~saw_nonzero & nonzero;
+ saw_nonzero |= nonzero;
+
+ int bits = bn_count_low_zero_bits_word(bn->d[i]);
+ ret |= first_nonzero & (i * BN_BITS2 + bits);
+ }
+
+ // If got to the end of |bn| and saw no non-zero words, |bn| is zero. |ret|
+ // will then remain zero.
+ return ret;
+}
git://repos.xcallymotion.com / motion2.git / blobdiff