1d9e397b599b13d642138480a28c14db7a136bf0Adam Langley/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 2d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * All rights reserved. 3d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 4d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * This package is an SSL implementation written 5d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * by Eric Young (eay@cryptsoft.com). 6d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * The implementation was written so as to conform with Netscapes SSL. 7d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 8d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * This library is free for commercial and non-commercial use as long as 9d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * the following conditions are aheared to. The following conditions 10d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * apply to all code found in this distribution, be it the RC4, RSA, 11d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * included with this distribution is covered by the same copyright terms 13d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * except that the holder is Tim Hudson (tjh@cryptsoft.com). 14d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 15d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * Copyright remains Eric Young's, and as such any Copyright notices in 16d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * the code are not to be removed. 17d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * If this package is used in a product, Eric Young should be given attribution 18d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * as the author of the parts of the library used. 19d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * This can be in the form of a textual message at program startup or 20d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * in documentation (online or textual) provided with the package. 21d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 22d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * Redistribution and use in source and binary forms, with or without 23d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * modification, are permitted provided that the following conditions 24d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * are met: 25d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 1. Redistributions of source code must retain the copyright 26d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * notice, this list of conditions and the following disclaimer. 27d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 2. Redistributions in binary form must reproduce the above copyright 28d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * notice, this list of conditions and the following disclaimer in the 29d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * documentation and/or other materials provided with the distribution. 30d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 3. All advertising materials mentioning features or use of this software 31d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * must display the following acknowledgement: 32d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * "This product includes cryptographic software written by 33d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * Eric Young (eay@cryptsoft.com)" 34d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * The word 'cryptographic' can be left out if the rouines from the library 35d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * being used are not cryptographic related :-). 36d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 4. If you include any Windows specific code (or a derivative thereof) from 37d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * the apps directory (application code) you must include an acknowledgement: 38d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 39d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 40d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * SUCH DAMAGE. 51d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 52d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * The licence and distribution terms for any publically available version or 53d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * derivative of this code cannot be changed. i.e. this code cannot simply be 54d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * copied and put under another distribution licence 55d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * [including the GNU Public Licence.] */ 56d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 57d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#include <openssl/bn.h> 58d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 59d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#include <limits.h> 60d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#include <openssl/err.h> 61d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 62d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#include "internal.h" 63d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 64d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 65d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#define asm __asm__ 66d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 67d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#if !defined(OPENSSL_NO_ASM) 68d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# if defined(__GNUC__) && __GNUC__>=2 69d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# if defined(OPENSSL_X86) 70d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* 71d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * There were two reasons for implementing this template: 72d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * - GNU C generates a call to a function (__udivdi3 to be exact) 73d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * in reply to ((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0 (I fail to 74d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * understand why...); 75d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * - divl doesn't only calculate quotient, but also leaves 76d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * remainder in %edx which we can definitely use here:-) 77d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 78d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * <appro@fy.chalmers.se> 79d9e397b599b13d642138480a28c14db7a136bf0Adam Langley */ 80d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#undef div_asm 81d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# define div_asm(n0,n1,d0) \ 82d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ({ asm volatile ( \ 83d9e397b599b13d642138480a28c14db7a136bf0Adam Langley "divl %4" \ 84d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "=a"(q), "=d"(rem) \ 85d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "a"(n1), "d"(n0), "g"(d0) \ 86d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "cc"); \ 87d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q; \ 88d9e397b599b13d642138480a28c14db7a136bf0Adam Langley }) 89d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# define REMAINDER_IS_ALREADY_CALCULATED 90d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# elif defined(OPENSSL_X86_64) 91d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* 92d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * Same story here, but it's 128-bit by 64-bit division. Wow! 93d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * <appro@fy.chalmers.se> 94d9e397b599b13d642138480a28c14db7a136bf0Adam Langley */ 95d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# undef div_asm 96d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# define div_asm(n0,n1,d0) \ 97d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ({ asm volatile ( \ 98d9e397b599b13d642138480a28c14db7a136bf0Adam Langley "divq %4" \ 99d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "=a"(q), "=d"(rem) \ 100d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "a"(n1), "d"(n0), "g"(d0) \ 101d9e397b599b13d642138480a28c14db7a136bf0Adam Langley : "cc"); \ 102d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q; \ 103d9e397b599b13d642138480a28c14db7a136bf0Adam Langley }) 104d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# define REMAINDER_IS_ALREADY_CALCULATED 105d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# endif /* __<cpu> */ 106d9e397b599b13d642138480a28c14db7a136bf0Adam Langley# endif /* __GNUC__ */ 107d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif /* OPENSSL_NO_ASM */ 108d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 109d9e397b599b13d642138480a28c14db7a136bf0Adam Langley/* BN_div computes dv := num / divisor, rounding towards 110d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * zero, and sets up rm such that dv*divisor + rm = num holds. 111d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * Thus: 112d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * dv->neg == num->neg ^ divisor->neg (unless the result is zero) 113d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * rm->neg == num->neg (unless the remainder is zero) 114d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * If 'dv' or 'rm' is NULL, the respective value is not returned. */ 115d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor, 116d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX *ctx) { 117d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int norm_shift, i, loop; 118d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BIGNUM *tmp, wnum, *snum, *sdiv, *res; 119d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG *resp, *wnump; 120d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG d0, d1; 121d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int num_n, div_n; 122d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int no_branch = 0; 123d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 124d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Invalid zero-padding would have particularly bad consequences 125d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * so don't just rely on bn_check_top() here */ 126d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if ((num->top > 0 && num->d[num->top - 1] == 0) || 127d9e397b599b13d642138480a28c14db7a136bf0Adam Langley (divisor->top > 0 && divisor->d[divisor->top - 1] == 0)) { 128d9e397b599b13d642138480a28c14db7a136bf0Adam Langley OPENSSL_PUT_ERROR(BN, BN_div, BN_R_NOT_INITIALIZED); 129d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 130d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 131d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 132d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if ((num->flags & BN_FLG_CONSTTIME) != 0 || 133d9e397b599b13d642138480a28c14db7a136bf0Adam Langley (divisor->flags & BN_FLG_CONSTTIME) != 0) { 134d9e397b599b13d642138480a28c14db7a136bf0Adam Langley no_branch = 1; 135d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 136d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 137d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_is_zero(divisor)) { 138d9e397b599b13d642138480a28c14db7a136bf0Adam Langley OPENSSL_PUT_ERROR(BN, BN_div, BN_R_DIV_BY_ZERO); 139d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 140d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 141d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 142d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!no_branch && BN_ucmp(num, divisor) < 0) { 143d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (rm != NULL) { 144d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_copy(rm, num) == NULL) { 145d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 146d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 147d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 148d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (dv != NULL) { 149d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_zero(dv); 150d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 151d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 152d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 153d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 154d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX_start(ctx); 155d9e397b599b13d642138480a28c14db7a136bf0Adam Langley tmp = BN_CTX_get(ctx); 156d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum = BN_CTX_get(ctx); 157d9e397b599b13d642138480a28c14db7a136bf0Adam Langley sdiv = BN_CTX_get(ctx); 158d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (dv == NULL) { 159d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res = BN_CTX_get(ctx); 160d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 161d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res = dv; 162d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 163d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL) { 164d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 165d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 166d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 167d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* First we normalise the numbers */ 168d9e397b599b13d642138480a28c14db7a136bf0Adam Langley norm_shift = BN_BITS2 - ((BN_num_bits(divisor)) % BN_BITS2); 169d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!(BN_lshift(sdiv, divisor, norm_shift))) { 170d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 171d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 172d9e397b599b13d642138480a28c14db7a136bf0Adam Langley sdiv->neg = 0; 173d9e397b599b13d642138480a28c14db7a136bf0Adam Langley norm_shift += BN_BITS2; 174d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!(BN_lshift(snum, num, norm_shift))) { 175d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 176d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 177d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum->neg = 0; 178d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 179d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (no_branch) { 180d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Since we don't know whether snum is larger than sdiv, 181d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * we pad snum with enough zeroes without changing its 182d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * value. 183d9e397b599b13d642138480a28c14db7a136bf0Adam Langley */ 184d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (snum->top <= sdiv->top + 1) { 185d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (bn_wexpand(snum, sdiv->top + 2) == NULL) { 186d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 187d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 188d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (i = snum->top; i < sdiv->top + 2; i++) { 189d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum->d[i] = 0; 190d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 191d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum->top = sdiv->top + 2; 192d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 193d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (bn_wexpand(snum, snum->top + 1) == NULL) { 194d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 195d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 196d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum->d[snum->top] = 0; 197d9e397b599b13d642138480a28c14db7a136bf0Adam Langley snum->top++; 198d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 199d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 200d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 201d9e397b599b13d642138480a28c14db7a136bf0Adam Langley div_n = sdiv->top; 202d9e397b599b13d642138480a28c14db7a136bf0Adam Langley num_n = snum->top; 203d9e397b599b13d642138480a28c14db7a136bf0Adam Langley loop = num_n - div_n; 204d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Lets setup a 'window' into snum 205d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * This is the part that corresponds to the current 206d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * 'area' being divided */ 207d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnum.neg = 0; 208d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnum.d = &(snum->d[loop]); 209d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnum.top = div_n; 210d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* only needed when BN_ucmp messes up the values between top and max */ 211d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */ 212d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 213d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Get the top 2 words of sdiv */ 214d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* div_n=sdiv->top; */ 215d9e397b599b13d642138480a28c14db7a136bf0Adam Langley d0 = sdiv->d[div_n - 1]; 216d9e397b599b13d642138480a28c14db7a136bf0Adam Langley d1 = (div_n == 1) ? 0 : sdiv->d[div_n - 2]; 217d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 218d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* pointer to the 'top' of snum */ 219d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnump = &(snum->d[num_n - 1]); 220d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 221d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Setup to 'res' */ 222d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res->neg = (num->neg ^ divisor->neg); 223d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!bn_wexpand(res, (loop + 1))) { 224d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 225d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 226d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res->top = loop - no_branch; 227d9e397b599b13d642138480a28c14db7a136bf0Adam Langley resp = &(res->d[loop - 1]); 228d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 229d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* space for temp */ 230d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!bn_wexpand(tmp, (div_n + 1))) { 231d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 232d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 233d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 234d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!no_branch) { 235d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_ucmp(&wnum, sdiv) >= 0) { 236d9e397b599b13d642138480a28c14db7a136bf0Adam Langley bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n); 237d9e397b599b13d642138480a28c14db7a136bf0Adam Langley *resp = 1; 238d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 239d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res->top--; 240d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 241d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 242d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 243d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* if res->top == 0 then clear the neg value otherwise decrease 244d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * the resp pointer */ 245d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (res->top == 0) { 246d9e397b599b13d642138480a28c14db7a136bf0Adam Langley res->neg = 0; 247d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 248d9e397b599b13d642138480a28c14db7a136bf0Adam Langley resp--; 249d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 250d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 251d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (i = 0; i < loop - 1; i++, wnump--, resp--) { 252d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG q, l0; 253d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* the first part of the loop uses the top two words of snum and sdiv to 254d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * calculate a BN_ULONG q such that | wnum - sdiv * q | < sdiv */ 255d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG n0, n1, rem = 0; 256d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 257d9e397b599b13d642138480a28c14db7a136bf0Adam Langley n0 = wnump[0]; 258d9e397b599b13d642138480a28c14db7a136bf0Adam Langley n1 = wnump[-1]; 259d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (n0 == d0) { 260d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q = BN_MASK2; 261d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 262d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* n0 < d0 */ 263d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#ifdef BN_LLONG 264d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULLONG t2; 265d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 266d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#if defined(BN_LLONG) && !defined(div_asm) 267d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q = (BN_ULONG)(((((BN_ULLONG)n0) << BN_BITS2) | n1) / d0); 268d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else 269d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q = div_asm(n0, n1, d0); 270d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 271d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 272d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#ifndef REMAINDER_IS_ALREADY_CALCULATED 273d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* rem doesn't have to be BN_ULLONG. The least we know it's less that d0, 274d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * isn't it? */ 275d9e397b599b13d642138480a28c14db7a136bf0Adam Langley rem = (n1 - q * d0) & BN_MASK2; 276d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 277d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 278d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2 = (BN_ULLONG)d1 * q; 279d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 280d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (;;) { 281e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if (t2 <= ((((BN_ULLONG)rem) << BN_BITS2) | wnump[-2])) { 282d9e397b599b13d642138480a28c14db7a136bf0Adam Langley break; 283e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 284d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q--; 285d9e397b599b13d642138480a28c14db7a136bf0Adam Langley rem += d0; 286e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if (rem < d0) { 287d9e397b599b13d642138480a28c14db7a136bf0Adam Langley break; /* don't let rem overflow */ 288e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 289d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2 -= d1; 290d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 291d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else /* !BN_LLONG */ 292d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG t2l, t2h; 293d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 294d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#if defined(div_asm) 295d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q = div_asm(n0, n1, d0); 296d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else 297d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q = bn_div_words(n0, n1, d0); 298d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 299d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 300d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#ifndef REMAINDER_IS_ALREADY_CALCULATED 301d9e397b599b13d642138480a28c14db7a136bf0Adam Langley rem = (n1 - q * d0) & BN_MASK2; 302d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 303d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 304d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#if defined(BN_UMULT_LOHI) 305d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_UMULT_LOHI(t2l, t2h, d1, q); 306d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#elif defined(BN_UMULT_HIGH) 307d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2l = d1 * q; 308d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2h = BN_UMULT_HIGH(d1, q); 309d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else 310d9e397b599b13d642138480a28c14db7a136bf0Adam Langley { 311d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG ql, qh; 312d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2l = LBITS(d1); 313d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2h = HBITS(d1); 314d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ql = LBITS(q); 315d9e397b599b13d642138480a28c14db7a136bf0Adam Langley qh = HBITS(q); 316d9e397b599b13d642138480a28c14db7a136bf0Adam Langley mul64(t2l, t2h, ql, qh); /* t2=(BN_ULLONG)d1*q; */ 317d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 318d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 319d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 320d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (;;) { 321e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if ((t2h < rem) || ((t2h == rem) && (t2l <= wnump[-2]))) { 322d9e397b599b13d642138480a28c14db7a136bf0Adam Langley break; 323e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 324d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q--; 325d9e397b599b13d642138480a28c14db7a136bf0Adam Langley rem += d0; 326e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if (rem < d0) { 327d9e397b599b13d642138480a28c14db7a136bf0Adam Langley break; /* don't let rem overflow */ 328e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 329e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if (t2l < d1) { 330d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2h--; 331e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 332d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t2l -= d1; 333d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 334d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif /* !BN_LLONG */ 335d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 336d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 337d9e397b599b13d642138480a28c14db7a136bf0Adam Langley l0 = bn_mul_words(tmp->d, sdiv->d, div_n, q); 338d9e397b599b13d642138480a28c14db7a136bf0Adam Langley tmp->d[div_n] = l0; 339d9e397b599b13d642138480a28c14db7a136bf0Adam Langley wnum.d--; 340d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* ingore top values of the bignums just sub the two 341d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * BN_ULONG arrays with bn_sub_words */ 342d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n + 1)) { 343d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Note: As we have considered only the leading 344d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * two BN_ULONGs in the calculation of q, sdiv * q 345d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * might be greater than wnum (but then (q-1) * sdiv 346d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * is less or equal than wnum) 347d9e397b599b13d642138480a28c14db7a136bf0Adam Langley */ 348d9e397b599b13d642138480a28c14db7a136bf0Adam Langley q--; 349d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n)) { 350d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* we can't have an overflow here (assuming 351d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * that q != 0, but if q == 0 then tmp is 352d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * zero anyway) */ 353d9e397b599b13d642138480a28c14db7a136bf0Adam Langley (*wnump)++; 354d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 355d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 356d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* store part of the result */ 357d9e397b599b13d642138480a28c14db7a136bf0Adam Langley *resp = q; 358d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 359d9e397b599b13d642138480a28c14db7a136bf0Adam Langley bn_correct_top(snum); 360d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (rm != NULL) { 361d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* Keep a copy of the neg flag in num because if rm==num 362d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * BN_rshift() will overwrite it. 363d9e397b599b13d642138480a28c14db7a136bf0Adam Langley */ 364d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int neg = num->neg; 365e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley if (!BN_rshift(rm, snum, norm_shift)) { 366e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley goto err; 367e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley } 368d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_is_zero(rm)) { 369d9e397b599b13d642138480a28c14db7a136bf0Adam Langley rm->neg = neg; 370d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 371d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 372d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (no_branch) { 373d9e397b599b13d642138480a28c14db7a136bf0Adam Langley bn_correct_top(res); 374d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 375d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX_end(ctx); 376d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 377d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 378d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyerr: 379d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX_end(ctx); 380d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 381d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 382d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 383d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx) { 384d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!(BN_mod(r, m, d, ctx))) { 385d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 386d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 387d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!r->neg) { 388d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 389d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 390d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 391d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* now -|d| < r < 0, so we have to set r := r + |d|. */ 392d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return (d->neg ? BN_sub : BN_add)(r, r, d); 393d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 394d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 395d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, 396d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX *ctx) { 397d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_add(r, a, b)) { 398d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 399d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 400d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_nnmod(r, r, m, ctx); 401d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 402d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 403d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, 404d9e397b599b13d642138480a28c14db7a136bf0Adam Langley const BIGNUM *m) { 405d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_uadd(r, a, b)) { 406d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 407d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 408d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_ucmp(r, m) >= 0) { 409d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_usub(r, r, m); 410d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 411d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 412d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 413d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 414d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, 415d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX *ctx) { 416d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_sub(r, a, b)) { 417d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 418d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 419d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_nnmod(r, r, m, ctx); 420d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 421d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 422d9e397b599b13d642138480a28c14db7a136bf0Adam Langley/* BN_mod_sub variant that may be used if both a and b are non-negative 423d9e397b599b13d642138480a28c14db7a136bf0Adam Langley * and less than m */ 424d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, 425d9e397b599b13d642138480a28c14db7a136bf0Adam Langley const BIGNUM *m) { 426d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_sub(r, a, b)) { 427d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 428d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 429d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (r->neg) { 430d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_add(r, r, m); 431d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 432d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 433d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 434d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 435d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m, 436d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX *ctx) { 437d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BIGNUM *t; 438d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int ret = 0; 439d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 440d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX_start(ctx); 441d9e397b599b13d642138480a28c14db7a136bf0Adam Langley t = BN_CTX_get(ctx); 442d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (t == NULL) { 443d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 444d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 445d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 446d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (a == b) { 447d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_sqr(t, a, ctx)) { 448d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 449d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 450d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 451d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_mul(t, a, b, ctx)) { 452d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 453d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 454d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 455d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 456d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_nnmod(r, t, m, ctx)) { 457d9e397b599b13d642138480a28c14db7a136bf0Adam Langley goto err; 458d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 459d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 460d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = 1; 461d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 462d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyerr: 463d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX_end(ctx); 464d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return ret; 465d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 466d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 467d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx) { 468d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_sqr(r, a, ctx)) { 469d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 470d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 471d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 472d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* r->neg == 0, thus we don't need BN_nnmod */ 473d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_mod(r, r, m, ctx); 474d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 475d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 476d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m, 477d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_CTX *ctx) { 478d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BIGNUM *abs_m = NULL; 479d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int ret; 480d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 481d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_nnmod(r, a, m, ctx)) { 482d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 483d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 484d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 485d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (m->neg) { 486d9e397b599b13d642138480a28c14db7a136bf0Adam Langley abs_m = BN_dup(m); 487d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (abs_m == NULL) { 488d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 489d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 490d9e397b599b13d642138480a28c14db7a136bf0Adam Langley abs_m->neg = 0; 491d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 492d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 493d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = BN_mod_lshift_quick(r, r, n, (abs_m ? abs_m : m)); 494d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 495e9ada863a7b3e81f5d2b1e3bdd2305da902a87f5Adam Langley BN_free(abs_m); 496d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return ret; 497d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 498d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 499d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m) { 500d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (r != a) { 501d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_copy(r, a) == NULL) { 502d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 503d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 504d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 505d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 506d9e397b599b13d642138480a28c14db7a136bf0Adam Langley while (n > 0) { 507d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int max_shift; 508d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 509d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* 0 < r < m */ 510d9e397b599b13d642138480a28c14db7a136bf0Adam Langley max_shift = BN_num_bits(m) - BN_num_bits(r); 511d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* max_shift >= 0 */ 512d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 513d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (max_shift < 0) { 514d9e397b599b13d642138480a28c14db7a136bf0Adam Langley OPENSSL_PUT_ERROR(BN, BN_mod_lshift_quick, BN_R_INPUT_NOT_REDUCED); 515d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 516d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 517d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 518d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (max_shift > n) { 519d9e397b599b13d642138480a28c14db7a136bf0Adam Langley max_shift = n; 520d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 521d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 522d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (max_shift) { 523d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_lshift(r, r, max_shift)) { 524d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 525d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 526d9e397b599b13d642138480a28c14db7a136bf0Adam Langley n -= max_shift; 527d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } else { 528d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_lshift1(r, r)) { 529d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 530d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 531d9e397b599b13d642138480a28c14db7a136bf0Adam Langley --n; 532d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 533d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 534d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* BN_num_bits(r) <= BN_num_bits(m) */ 535d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_cmp(r, m) >= 0) { 536d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_sub(r, r, m)) { 537d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 538d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 539d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 540d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 541d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 542d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 543d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 544d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 545d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx) { 546d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_lshift1(r, a)) { 547d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 548d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 549d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 550d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_nnmod(r, r, m, ctx); 551d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 552d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 553d9e397b599b13d642138480a28c14db7a136bf0Adam Langleyint BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m) { 554d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_lshift1(r, a)) { 555d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 556d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 557d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (BN_cmp(r, m) >= 0) { 558d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return BN_sub(r, r, m); 559d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 560d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 561d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 1; 562d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 563d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 564d9e397b599b13d642138480a28c14db7a136bf0Adam LangleyBN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w) { 565d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG ret = 0; 566d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int i, j; 567d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 568d9e397b599b13d642138480a28c14db7a136bf0Adam Langley w &= BN_MASK2; 569d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 570d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!w) { 571d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* actually this an error (division by zero) */ 572d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return (BN_ULONG) - 1; 573d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 574d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 575d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (a->top == 0) { 576d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return 0; 577d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 578d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 579d9e397b599b13d642138480a28c14db7a136bf0Adam Langley /* normalize input (so bn_div_words doesn't complain) */ 580d9e397b599b13d642138480a28c14db7a136bf0Adam Langley j = BN_BITS2 - BN_num_bits_word(w); 581d9e397b599b13d642138480a28c14db7a136bf0Adam Langley w <<= j; 582d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (!BN_lshift(a, a, j)) { 583d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return (BN_ULONG) - 1; 584d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 585d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 586d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (i = a->top - 1; i >= 0; i--) { 587d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG l, d; 588d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 589d9e397b599b13d642138480a28c14db7a136bf0Adam Langley l = a->d[i]; 590d9e397b599b13d642138480a28c14db7a136bf0Adam Langley d = bn_div_words(ret, l, w); 591d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = (l - ((d * w) & BN_MASK2)) & BN_MASK2; 592d9e397b599b13d642138480a28c14db7a136bf0Adam Langley a->d[i] = d; 593d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 594d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 595d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if ((a->top > 0) && (a->d[a->top - 1] == 0)) { 596d9e397b599b13d642138480a28c14db7a136bf0Adam Langley a->top--; 597d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 598d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 599d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret >>= j; 600d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return ret; 601d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 602d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 603d9e397b599b13d642138480a28c14db7a136bf0Adam LangleyBN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) { 604d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#ifndef BN_LLONG 605d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULONG ret = 0; 606d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else 607d9e397b599b13d642138480a28c14db7a136bf0Adam Langley BN_ULLONG ret = 0; 608d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 609d9e397b599b13d642138480a28c14db7a136bf0Adam Langley int i; 610d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 611d9e397b599b13d642138480a28c14db7a136bf0Adam Langley if (w == 0) { 612d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return (BN_ULONG) -1; 613d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 614d9e397b599b13d642138480a28c14db7a136bf0Adam Langley 615d9e397b599b13d642138480a28c14db7a136bf0Adam Langley w &= BN_MASK2; 616d9e397b599b13d642138480a28c14db7a136bf0Adam Langley for (i = a->top - 1; i >= 0; i--) { 617d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#ifndef BN_LLONG 618d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = ((ret << BN_BITS4) | ((a->d[i] >> BN_BITS4) & BN_MASK2l)) % w; 619d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = ((ret << BN_BITS4) | (a->d[i] & BN_MASK2l)) % w; 620d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#else 621d9e397b599b13d642138480a28c14db7a136bf0Adam Langley ret = (BN_ULLONG)(((ret << (BN_ULLONG)BN_BITS2) | a->d[i]) % (BN_ULLONG)w); 622d9e397b599b13d642138480a28c14db7a136bf0Adam Langley#endif 623d9e397b599b13d642138480a28c14db7a136bf0Adam Langley } 624d9e397b599b13d642138480a28c14db7a136bf0Adam Langley return (BN_ULONG)ret; 625d9e397b599b13d642138480a28c14db7a136bf0Adam Langley} 626