mirror of
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941 lines
19 KiB
C
941 lines
19 KiB
C
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/* $OpenBSD: bn_lib.c,v 1.47 2019/06/17 17:11:48 tb Exp $ */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#ifndef BN_DEBUG
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# undef NDEBUG /* avoid conflicting definitions */
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# define NDEBUG
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#endif
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#include <assert.h>
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <openssl/opensslconf.h>
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#include <openssl/err.h>
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#include "bn_lcl.h"
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/* This stuff appears to be completely unused, so is deprecated */
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#ifndef OPENSSL_NO_DEPRECATED
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/* For a 32 bit machine
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* 2 - 4 == 128
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* 3 - 8 == 256
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* 4 - 16 == 512
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* 5 - 32 == 1024
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* 6 - 64 == 2048
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* 7 - 128 == 4096
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* 8 - 256 == 8192
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*/
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static int bn_limit_bits = 0;
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static int bn_limit_num = 8; /* (1<<bn_limit_bits) */
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static int bn_limit_bits_low = 0;
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static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
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static int bn_limit_bits_high = 0;
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static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
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static int bn_limit_bits_mont = 0;
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static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
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void
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BN_set_params(int mult, int high, int low, int mont)
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{
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if (mult >= 0) {
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if (mult > (int)(sizeof(int) * 8) - 1)
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mult = sizeof(int) * 8 - 1;
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bn_limit_bits = mult;
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bn_limit_num = 1 << mult;
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}
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if (high >= 0) {
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if (high > (int)(sizeof(int) * 8) - 1)
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high = sizeof(int) * 8 - 1;
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bn_limit_bits_high = high;
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bn_limit_num_high = 1 << high;
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}
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if (low >= 0) {
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if (low > (int)(sizeof(int) * 8) - 1)
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low = sizeof(int) * 8 - 1;
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bn_limit_bits_low = low;
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bn_limit_num_low = 1 << low;
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}
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if (mont >= 0) {
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if (mont > (int)(sizeof(int) * 8) - 1)
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mont = sizeof(int) * 8 - 1;
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bn_limit_bits_mont = mont;
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bn_limit_num_mont = 1 << mont;
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}
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}
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int
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BN_get_params(int which)
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{
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if (which == 0)
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return (bn_limit_bits);
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else if (which == 1)
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return (bn_limit_bits_high);
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else if (which == 2)
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return (bn_limit_bits_low);
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else if (which == 3)
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return (bn_limit_bits_mont);
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else
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return (0);
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}
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#endif
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const BIGNUM *
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BN_value_one(void)
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{
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static const BN_ULONG data_one = 1L;
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static const BIGNUM const_one = {
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(BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA
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};
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return (&const_one);
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}
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int
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BN_num_bits_word(BN_ULONG l)
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{
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BN_ULONG x, mask;
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int bits;
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unsigned int shift;
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/* Constant time calculation of floor(log2(l)) + 1. */
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bits = (l != 0);
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shift = BN_BITS4; /* On _LP64 this is 32, otherwise 16. */
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do {
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x = l >> shift;
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/* If x is 0, set mask to 0, otherwise set it to all 1s. */
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mask = ((~x & (x - 1)) >> (BN_BITS2 - 1)) - 1;
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bits += shift & mask;
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/* If x is 0, leave l alone, otherwise set l = x. */
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l ^= (x ^ l) & mask;
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} while ((shift /= 2) != 0);
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return bits;
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}
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int
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BN_num_bits(const BIGNUM *a)
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{
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int i = a->top - 1;
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bn_check_top(a);
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if (BN_is_zero(a))
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return 0;
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return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));
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}
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void
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BN_clear_free(BIGNUM *a)
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{
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int i;
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if (a == NULL)
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return;
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bn_check_top(a);
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if (a->d != NULL && !(BN_get_flags(a, BN_FLG_STATIC_DATA)))
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freezero(a->d, a->dmax * sizeof(a->d[0]));
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i = BN_get_flags(a, BN_FLG_MALLOCED);
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explicit_bzero(a, sizeof(BIGNUM));
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if (i)
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free(a);
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}
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void
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BN_free(BIGNUM *a)
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{
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BN_clear_free(a);
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}
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void
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BN_init(BIGNUM *a)
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{
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memset(a, 0, sizeof(BIGNUM));
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bn_check_top(a);
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}
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BIGNUM *
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BN_new(void)
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{
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BIGNUM *ret;
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if ((ret = malloc(sizeof(BIGNUM))) == NULL) {
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BNerror(ERR_R_MALLOC_FAILURE);
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return (NULL);
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}
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ret->flags = BN_FLG_MALLOCED;
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ret->top = 0;
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ret->neg = 0;
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ret->dmax = 0;
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ret->d = NULL;
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bn_check_top(ret);
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return (ret);
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}
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/* This is used both by bn_expand2() and bn_dup_expand() */
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/* The caller MUST check that words > b->dmax before calling this */
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static BN_ULONG *
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bn_expand_internal(const BIGNUM *b, int words)
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{
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BN_ULONG *A, *a = NULL;
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const BN_ULONG *B;
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int i;
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bn_check_top(b);
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if (words > (INT_MAX/(4*BN_BITS2))) {
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BNerror(BN_R_BIGNUM_TOO_LONG);
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return NULL;
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}
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if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
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BNerror(BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
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return (NULL);
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}
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a = A = reallocarray(NULL, words, sizeof(BN_ULONG));
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if (A == NULL) {
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BNerror(ERR_R_MALLOC_FAILURE);
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return (NULL);
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}
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#if 1
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B = b->d;
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/* Check if the previous number needs to be copied */
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if (B != NULL) {
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for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
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/*
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* The fact that the loop is unrolled
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* 4-wise is a tribute to Intel. It's
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* the one that doesn't have enough
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* registers to accommodate more data.
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* I'd unroll it 8-wise otherwise:-)
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*
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* <appro@fy.chalmers.se>
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*/
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BN_ULONG a0, a1, a2, a3;
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a0 = B[0];
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a1 = B[1];
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a2 = B[2];
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a3 = B[3];
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A[0] = a0;
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A[1] = a1;
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A[2] = a2;
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A[3] = a3;
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}
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switch (b->top & 3) {
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case 3:
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A[2] = B[2];
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case 2:
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A[1] = B[1];
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case 1:
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A[0] = B[0];
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}
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}
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#else
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memset(A, 0, sizeof(BN_ULONG) * words);
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memcpy(A, b->d, sizeof(b->d[0]) * b->top);
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#endif
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return (a);
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}
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/* This is an internal function that can be used instead of bn_expand2()
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* when there is a need to copy BIGNUMs instead of only expanding the
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* data part, while still expanding them.
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* Especially useful when needing to expand BIGNUMs that are declared
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* 'const' and should therefore not be changed.
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* The reason to use this instead of a BN_dup() followed by a bn_expand2()
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* is memory allocation overhead. A BN_dup() followed by a bn_expand2()
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* will allocate new memory for the BIGNUM data twice, and free it once,
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* while bn_dup_expand() makes sure allocation is made only once.
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*/
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#ifndef OPENSSL_NO_DEPRECATED
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BIGNUM *
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bn_dup_expand(const BIGNUM *b, int words)
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{
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BIGNUM *r = NULL;
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bn_check_top(b);
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/* This function does not work if
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* words <= b->dmax && top < words
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* because BN_dup() does not preserve 'dmax'!
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* (But bn_dup_expand() is not used anywhere yet.)
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*/
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if (words > b->dmax) {
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BN_ULONG *a = bn_expand_internal(b, words);
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if (a) {
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r = BN_new();
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if (r) {
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r->top = b->top;
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r->dmax = words;
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r->neg = b->neg;
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r->d = a;
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} else {
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/* r == NULL, BN_new failure */
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free(a);
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}
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}
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/* If a == NULL, there was an error in allocation in
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bn_expand_internal(), and NULL should be returned */
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} else {
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r = BN_dup(b);
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}
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bn_check_top(r);
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return r;
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}
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#endif
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/* This is an internal function that should not be used in applications.
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* It ensures that 'b' has enough room for a 'words' word number
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* and initialises any unused part of b->d with leading zeros.
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* It is mostly used by the various BIGNUM routines. If there is an error,
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* NULL is returned. If not, 'b' is returned. */
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BIGNUM *
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bn_expand2(BIGNUM *b, int words)
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{
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bn_check_top(b);
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if (words > b->dmax) {
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BN_ULONG *a = bn_expand_internal(b, words);
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if (!a)
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return NULL;
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if (b->d)
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freezero(b->d, b->dmax * sizeof(b->d[0]));
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b->d = a;
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b->dmax = words;
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}
|
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/* None of this should be necessary because of what b->top means! */
|
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#if 0
|
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/* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
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if (b->top < b->dmax) {
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int i;
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BN_ULONG *A = &(b->d[b->top]);
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for (i = (b->dmax - b->top) >> 3; i > 0; i--, A += 8) {
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A[0] = 0;
|
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A[1] = 0;
|
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A[2] = 0;
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A[3] = 0;
|
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A[4] = 0;
|
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A[5] = 0;
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A[6] = 0;
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A[7] = 0;
|
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|
}
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for (i = (b->dmax - b->top)&7; i > 0; i--, A++)
|
||
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A[0] = 0;
|
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assert(A == &(b->d[b->dmax]));
|
||
|
}
|
||
|
#endif
|
||
|
bn_check_top(b);
|
||
|
return b;
|
||
|
}
|
||
|
|
||
|
BIGNUM *
|
||
|
BN_dup(const BIGNUM *a)
|
||
|
{
|
||
|
BIGNUM *t;
|
||
|
|
||
|
if (a == NULL)
|
||
|
return NULL;
|
||
|
bn_check_top(a);
|
||
|
|
||
|
t = BN_new();
|
||
|
if (t == NULL)
|
||
|
return NULL;
|
||
|
if (!BN_copy(t, a)) {
|
||
|
BN_free(t);
|
||
|
return NULL;
|
||
|
}
|
||
|
bn_check_top(t);
|
||
|
return t;
|
||
|
}
|
||
|
|
||
|
BIGNUM *
|
||
|
BN_copy(BIGNUM *a, const BIGNUM *b)
|
||
|
{
|
||
|
int i;
|
||
|
BN_ULONG *A;
|
||
|
const BN_ULONG *B;
|
||
|
|
||
|
bn_check_top(b);
|
||
|
|
||
|
if (a == b)
|
||
|
return (a);
|
||
|
if (bn_wexpand(a, b->top) == NULL)
|
||
|
return (NULL);
|
||
|
|
||
|
#if 1
|
||
|
A = a->d;
|
||
|
B = b->d;
|
||
|
for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
|
||
|
BN_ULONG a0, a1, a2, a3;
|
||
|
a0 = B[0];
|
||
|
a1 = B[1];
|
||
|
a2 = B[2];
|
||
|
a3 = B[3];
|
||
|
A[0] = a0;
|
||
|
A[1] = a1;
|
||
|
A[2] = a2;
|
||
|
A[3] = a3;
|
||
|
}
|
||
|
switch (b->top & 3) {
|
||
|
case 3:
|
||
|
A[2] = B[2];
|
||
|
case 2:
|
||
|
A[1] = B[1];
|
||
|
case 1:
|
||
|
A[0] = B[0];
|
||
|
}
|
||
|
#else
|
||
|
memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
|
||
|
#endif
|
||
|
|
||
|
a->top = b->top;
|
||
|
a->neg = b->neg;
|
||
|
bn_check_top(a);
|
||
|
return (a);
|
||
|
}
|
||
|
|
||
|
void
|
||
|
BN_swap(BIGNUM *a, BIGNUM *b)
|
||
|
{
|
||
|
int flags_old_a, flags_old_b;
|
||
|
BN_ULONG *tmp_d;
|
||
|
int tmp_top, tmp_dmax, tmp_neg;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
bn_check_top(b);
|
||
|
|
||
|
flags_old_a = a->flags;
|
||
|
flags_old_b = b->flags;
|
||
|
|
||
|
tmp_d = a->d;
|
||
|
tmp_top = a->top;
|
||
|
tmp_dmax = a->dmax;
|
||
|
tmp_neg = a->neg;
|
||
|
|
||
|
a->d = b->d;
|
||
|
a->top = b->top;
|
||
|
a->dmax = b->dmax;
|
||
|
a->neg = b->neg;
|
||
|
|
||
|
b->d = tmp_d;
|
||
|
b->top = tmp_top;
|
||
|
b->dmax = tmp_dmax;
|
||
|
b->neg = tmp_neg;
|
||
|
|
||
|
a->flags = (flags_old_a & BN_FLG_MALLOCED) |
|
||
|
(flags_old_b & BN_FLG_STATIC_DATA);
|
||
|
b->flags = (flags_old_b & BN_FLG_MALLOCED) |
|
||
|
(flags_old_a & BN_FLG_STATIC_DATA);
|
||
|
bn_check_top(a);
|
||
|
bn_check_top(b);
|
||
|
}
|
||
|
|
||
|
void
|
||
|
BN_clear(BIGNUM *a)
|
||
|
{
|
||
|
bn_check_top(a);
|
||
|
if (a->d != NULL)
|
||
|
explicit_bzero(a->d, a->dmax * sizeof(a->d[0]));
|
||
|
a->top = 0;
|
||
|
a->neg = 0;
|
||
|
}
|
||
|
|
||
|
BN_ULONG
|
||
|
BN_get_word(const BIGNUM *a)
|
||
|
{
|
||
|
if (a->top > 1)
|
||
|
return BN_MASK2;
|
||
|
else if (a->top == 1)
|
||
|
return a->d[0];
|
||
|
/* a->top == 0 */
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
BIGNUM *
|
||
|
bn_expand(BIGNUM *a, int bits)
|
||
|
{
|
||
|
if (bits > (INT_MAX - BN_BITS2 + 1))
|
||
|
return (NULL);
|
||
|
|
||
|
if (((bits + BN_BITS2 - 1) / BN_BITS2) <= a->dmax)
|
||
|
return (a);
|
||
|
|
||
|
return bn_expand2(a, (bits + BN_BITS2 - 1) / BN_BITS2);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_set_word(BIGNUM *a, BN_ULONG w)
|
||
|
{
|
||
|
bn_check_top(a);
|
||
|
if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
|
||
|
return (0);
|
||
|
a->neg = 0;
|
||
|
a->d[0] = w;
|
||
|
a->top = (w ? 1 : 0);
|
||
|
bn_check_top(a);
|
||
|
return (1);
|
||
|
}
|
||
|
|
||
|
BIGNUM *
|
||
|
BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
|
||
|
{
|
||
|
unsigned int i, m;
|
||
|
unsigned int n;
|
||
|
BN_ULONG l;
|
||
|
BIGNUM *bn = NULL;
|
||
|
|
||
|
if (len < 0)
|
||
|
return (NULL);
|
||
|
if (ret == NULL)
|
||
|
ret = bn = BN_new();
|
||
|
if (ret == NULL)
|
||
|
return (NULL);
|
||
|
bn_check_top(ret);
|
||
|
l = 0;
|
||
|
n = len;
|
||
|
if (n == 0) {
|
||
|
ret->top = 0;
|
||
|
return (ret);
|
||
|
}
|
||
|
i = ((n - 1) / BN_BYTES) + 1;
|
||
|
m = ((n - 1) % (BN_BYTES));
|
||
|
if (bn_wexpand(ret, (int)i) == NULL) {
|
||
|
BN_free(bn);
|
||
|
return NULL;
|
||
|
}
|
||
|
ret->top = i;
|
||
|
ret->neg = 0;
|
||
|
while (n--) {
|
||
|
l = (l << 8L) | *(s++);
|
||
|
if (m-- == 0) {
|
||
|
ret->d[--i] = l;
|
||
|
l = 0;
|
||
|
m = BN_BYTES - 1;
|
||
|
}
|
||
|
}
|
||
|
/* need to call this due to clear byte at top if avoiding
|
||
|
* having the top bit set (-ve number) */
|
||
|
bn_correct_top(ret);
|
||
|
return (ret);
|
||
|
}
|
||
|
|
||
|
/* ignore negative */
|
||
|
int
|
||
|
BN_bn2bin(const BIGNUM *a, unsigned char *to)
|
||
|
{
|
||
|
int n, i;
|
||
|
BN_ULONG l;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
n = i=BN_num_bytes(a);
|
||
|
while (i--) {
|
||
|
l = a->d[i / BN_BYTES];
|
||
|
*(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
|
||
|
}
|
||
|
return (n);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_ucmp(const BIGNUM *a, const BIGNUM *b)
|
||
|
{
|
||
|
int i;
|
||
|
BN_ULONG t1, t2, *ap, *bp;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
bn_check_top(b);
|
||
|
|
||
|
i = a->top - b->top;
|
||
|
if (i != 0)
|
||
|
return (i);
|
||
|
ap = a->d;
|
||
|
bp = b->d;
|
||
|
for (i = a->top - 1; i >= 0; i--) {
|
||
|
t1 = ap[i];
|
||
|
t2 = bp[i];
|
||
|
if (t1 != t2)
|
||
|
return ((t1 > t2) ? 1 : -1);
|
||
|
}
|
||
|
return (0);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_cmp(const BIGNUM *a, const BIGNUM *b)
|
||
|
{
|
||
|
int i;
|
||
|
int gt, lt;
|
||
|
BN_ULONG t1, t2;
|
||
|
|
||
|
if ((a == NULL) || (b == NULL)) {
|
||
|
if (a != NULL)
|
||
|
return (-1);
|
||
|
else if (b != NULL)
|
||
|
return (1);
|
||
|
else
|
||
|
return (0);
|
||
|
}
|
||
|
|
||
|
bn_check_top(a);
|
||
|
bn_check_top(b);
|
||
|
|
||
|
if (a->neg != b->neg) {
|
||
|
if (a->neg)
|
||
|
return (-1);
|
||
|
else
|
||
|
return (1);
|
||
|
}
|
||
|
if (a->neg == 0) {
|
||
|
gt = 1;
|
||
|
lt = -1;
|
||
|
} else {
|
||
|
gt = -1;
|
||
|
lt = 1;
|
||
|
}
|
||
|
|
||
|
if (a->top > b->top)
|
||
|
return (gt);
|
||
|
if (a->top < b->top)
|
||
|
return (lt);
|
||
|
for (i = a->top - 1; i >= 0; i--) {
|
||
|
t1 = a->d[i];
|
||
|
t2 = b->d[i];
|
||
|
if (t1 > t2)
|
||
|
return (gt);
|
||
|
if (t1 < t2)
|
||
|
return (lt);
|
||
|
}
|
||
|
return (0);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_set_bit(BIGNUM *a, int n)
|
||
|
{
|
||
|
int i, j, k;
|
||
|
|
||
|
if (n < 0)
|
||
|
return 0;
|
||
|
|
||
|
i = n / BN_BITS2;
|
||
|
j = n % BN_BITS2;
|
||
|
if (a->top <= i) {
|
||
|
if (bn_wexpand(a, i + 1) == NULL)
|
||
|
return (0);
|
||
|
for (k = a->top; k < i + 1; k++)
|
||
|
a->d[k] = 0;
|
||
|
a->top = i + 1;
|
||
|
}
|
||
|
|
||
|
a->d[i] |= (((BN_ULONG)1) << j);
|
||
|
bn_check_top(a);
|
||
|
return (1);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_clear_bit(BIGNUM *a, int n)
|
||
|
{
|
||
|
int i, j;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
if (n < 0)
|
||
|
return 0;
|
||
|
|
||
|
i = n / BN_BITS2;
|
||
|
j = n % BN_BITS2;
|
||
|
if (a->top <= i)
|
||
|
return (0);
|
||
|
|
||
|
a->d[i] &= (~(((BN_ULONG)1) << j));
|
||
|
bn_correct_top(a);
|
||
|
return (1);
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_is_bit_set(const BIGNUM *a, int n)
|
||
|
{
|
||
|
int i, j;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
if (n < 0)
|
||
|
return 0;
|
||
|
i = n / BN_BITS2;
|
||
|
j = n % BN_BITS2;
|
||
|
if (a->top <= i)
|
||
|
return 0;
|
||
|
return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
|
||
|
}
|
||
|
|
||
|
int
|
||
|
BN_mask_bits(BIGNUM *a, int n)
|
||
|
{
|
||
|
int b, w;
|
||
|
|
||
|
bn_check_top(a);
|
||
|
if (n < 0)
|
||
|
return 0;
|
||
|
|
||
|
w = n / BN_BITS2;
|
||
|
b = n % BN_BITS2;
|
||
|
if (w >= a->top)
|
||
|
return 0;
|
||
|
if (b == 0)
|
||
|
a->top = w;
|
||
|
else {
|
||
|
a->top = w + 1;
|
||
|
a->d[w] &= ~(BN_MASK2 << b);
|
||
|
}
|
||
|
bn_correct_top(a);
|
||
|
return (1);
|
||
|
}
|
||
|
|
||
|
void
|
||
|
BN_set_negative(BIGNUM *a, int b)
|
||
|
{
|
||
|
if (b && !BN_is_zero(a))
|
||
|
a->neg = 1;
|
||
|
else
|
||
|
a->neg = 0;
|
||
|
}
|
||
|
|
||
|
int
|
||
|
bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
|
||
|
{
|
||
|
int i;
|
||
|
BN_ULONG aa, bb;
|
||
|
|
||
|
aa = a[n - 1];
|
||
|
bb = b[n - 1];
|
||
|
if (aa != bb)
|
||
|
return ((aa > bb) ? 1 : -1);
|
||
|
for (i = n - 2; i >= 0; i--) {
|
||
|
aa = a[i];
|
||
|
bb = b[i];
|
||
|
if (aa != bb)
|
||
|
return ((aa > bb) ? 1 : -1);
|
||
|
}
|
||
|
return (0);
|
||
|
}
|
||
|
|
||
|
/* Here follows a specialised variants of bn_cmp_words(). It has the
|
||
|
property of performing the operation on arrays of different sizes.
|
||
|
The sizes of those arrays is expressed through cl, which is the
|
||
|
common length ( basicall, min(len(a),len(b)) ), and dl, which is the
|
||
|
delta between the two lengths, calculated as len(a)-len(b).
|
||
|
All lengths are the number of BN_ULONGs... */
|
||
|
|
||
|
int
|
||
|
bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
|
||
|
{
|
||
|
int n, i;
|
||
|
|
||
|
n = cl - 1;
|
||
|
|
||
|
if (dl < 0) {
|
||
|
for (i = dl; i < 0; i++) {
|
||
|
if (b[n - i] != 0)
|
||
|
return -1; /* a < b */
|
||
|
}
|
||
|
}
|
||
|
if (dl > 0) {
|
||
|
for (i = dl; i > 0; i--) {
|
||
|
if (a[n + i] != 0)
|
||
|
return 1; /* a > b */
|
||
|
}
|
||
|
}
|
||
|
return bn_cmp_words(a, b, cl);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Constant-time conditional swap of a and b.
|
||
|
* a and b are swapped if condition is not 0.
|
||
|
* The code assumes that at most one bit of condition is set.
|
||
|
* nwords is the number of words to swap.
|
||
|
* The code assumes that at least nwords are allocated in both a and b,
|
||
|
* and that no more than nwords are used by either a or b.
|
||
|
* a and b cannot be the same number
|
||
|
*/
|
||
|
void
|
||
|
BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
|
||
|
{
|
||
|
BN_ULONG t;
|
||
|
int i;
|
||
|
|
||
|
bn_wcheck_size(a, nwords);
|
||
|
bn_wcheck_size(b, nwords);
|
||
|
|
||
|
assert(a != b);
|
||
|
assert((condition & (condition - 1)) == 0);
|
||
|
assert(sizeof(BN_ULONG) >= sizeof(int));
|
||
|
|
||
|
condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
|
||
|
|
||
|
t = (a->top^b->top) & condition;
|
||
|
a->top ^= t;
|
||
|
b->top ^= t;
|
||
|
|
||
|
#define BN_CONSTTIME_SWAP(ind) \
|
||
|
do { \
|
||
|
t = (a->d[ind] ^ b->d[ind]) & condition; \
|
||
|
a->d[ind] ^= t; \
|
||
|
b->d[ind] ^= t; \
|
||
|
} while (0)
|
||
|
|
||
|
|
||
|
switch (nwords) {
|
||
|
default:
|
||
|
for (i = 10; i < nwords; i++)
|
||
|
BN_CONSTTIME_SWAP(i);
|
||
|
/* Fallthrough */
|
||
|
case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
|
||
|
case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
|
||
|
case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
|
||
|
case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
|
||
|
case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
|
||
|
case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
|
||
|
case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
|
||
|
case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
|
||
|
case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
|
||
|
case 1:
|
||
|
BN_CONSTTIME_SWAP(0);
|
||
|
}
|
||
|
#undef BN_CONSTTIME_SWAP
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Constant-time conditional swap of a and b.
|
||
|
* a and b are swapped if condition is not 0.
|
||
|
* nwords is the number of words to swap.
|
||
|
*/
|
||
|
int
|
||
|
BN_swap_ct(BN_ULONG condition, BIGNUM *a, BIGNUM *b, size_t nwords)
|
||
|
{
|
||
|
BN_ULONG t;
|
||
|
int i, words;
|
||
|
|
||
|
if (a == b)
|
||
|
return 1;
|
||
|
if (nwords > INT_MAX)
|
||
|
return 0;
|
||
|
words = (int)nwords;
|
||
|
if (bn_wexpand(a, words) == NULL || bn_wexpand(b, words) == NULL)
|
||
|
return 0;
|
||
|
if (a->top > words || b->top > words) {
|
||
|
BNerror(BN_R_INVALID_LENGTH);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/* Set condition to 0 (if it was zero) or all 1s otherwise. */
|
||
|
condition = ((~condition & (condition - 1)) >> (BN_BITS2 - 1)) - 1;
|
||
|
|
||
|
/* swap top field */
|
||
|
t = (a->top ^ b->top) & condition;
|
||
|
a->top ^= t;
|
||
|
b->top ^= t;
|
||
|
|
||
|
/* swap neg field */
|
||
|
t = (a->neg ^ b->neg) & condition;
|
||
|
a->neg ^= t;
|
||
|
b->neg ^= t;
|
||
|
|
||
|
/* swap BN_FLG_CONSTTIME from flag field */
|
||
|
t = ((a->flags ^ b->flags) & BN_FLG_CONSTTIME) & condition;
|
||
|
a->flags ^= t;
|
||
|
b->flags ^= t;
|
||
|
|
||
|
/* swap the data */
|
||
|
for (i = 0; i < words; i++) {
|
||
|
t = (a->d[i] ^ b->d[i]) & condition;
|
||
|
a->d[i] ^= t;
|
||
|
b->d[i] ^= t;
|
||
|
}
|
||
|
|
||
|
return 1;
|
||
|
}
|
||
|
|
||
|
BN_GENCB *
|
||
|
BN_GENCB_new(void)
|
||
|
{
|
||
|
BN_GENCB *cb;
|
||
|
|
||
|
if ((cb = calloc(1, sizeof(*cb))) == NULL)
|
||
|
return NULL;
|
||
|
|
||
|
return cb;
|
||
|
}
|
||
|
|
||
|
void
|
||
|
BN_GENCB_free(BN_GENCB *cb)
|
||
|
{
|
||
|
if (cb == NULL)
|
||
|
return;
|
||
|
free(cb);
|
||
|
}
|
||
|
|
||
|
void *
|
||
|
BN_GENCB_get_arg(BN_GENCB *cb)
|
||
|
{
|
||
|
return cb->arg;
|
||
|
}
|