X-Git-Url: https://git.openssl.org/gitweb/?a=blobdiff_plain;f=crypto%2Fbn%2Fbn_sqr.c;h=a62bb1a584805d25e72a4fcb3dc2feb3157e6712;hb=fe71bb3ad97ed01ccf92812891cc2bc3ef3dce76;hp=a8464610e5af8fc4f650cf9d93163f22cc7b6a36;hpb=7dfb0b774e6592dcbfe47015168a0ac8b44e2a17;p=openssl.git diff --git a/crypto/bn/bn_sqr.c b/crypto/bn/bn_sqr.c index a8464610e5..a62bb1a584 100644 --- a/crypto/bn/bn_sqr.c +++ b/crypto/bn/bn_sqr.c @@ -1,122 +1,234 @@ -/* crypto/bn/bn_sqr.c */ -/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) - * All rights reserved. +/* + * Copyright 1995-2016 The OpenSSL Project Authors. 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.] + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html */ -#include -#include "cryptlib.h" +#include "internal/cryptlib.h" #include "bn_lcl.h" /* r must not be a */ -/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */ -int BN_sqr(r, a, ctx) -BIGNUM *r; -BIGNUM *a; -BN_CTX *ctx; - { - int i,j,max,al; - BIGNUM *tmp; - BN_ULONG *ap,*rp; - - tmp=ctx->bn[ctx->tos]; - - al=a->top; - if (al == 0) - { - r->top=0; - return(1); - } - - max=(al*2); - if (bn_wexpand(r,1+max) == NULL) return(0); - if (bn_wexpand(tmp,1+max) == NULL) return(0); - - r->neg=0; - - ap=a->d; - rp=r->d; - rp[0]=rp[max-1]=0; - rp++; - j=al; - - if (--j > 0) - { - ap++; - rp[j]=bn_mul_words(rp,ap,j,ap[-1]); - rp+=2; - } - - for (i=2; id,r->d,r->d,max); - - /* There will not be a carry */ - - bn_sqr_words(tmp->d,a->d,al); - - bn_add_words(r->d,r->d,tmp->d,max); - - r->top=max; - if (r->d[max-1] == 0) r->top--; - return(1); - } +/* + * I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 + */ +int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) +{ + int max, al; + int ret = 0; + BIGNUM *tmp, *rr; + + bn_check_top(a); + + al = a->top; + if (al <= 0) { + r->top = 0; + r->neg = 0; + return 1; + } + + BN_CTX_start(ctx); + rr = (a != r) ? r : BN_CTX_get(ctx); + tmp = BN_CTX_get(ctx); + if (!rr || !tmp) + goto err; + + max = 2 * al; /* Non-zero (from above) */ + if (bn_wexpand(rr, max) == NULL) + goto err; + + if (al == 4) { +#ifndef BN_SQR_COMBA + BN_ULONG t[8]; + bn_sqr_normal(rr->d, a->d, 4, t); +#else + bn_sqr_comba4(rr->d, a->d); +#endif + } else if (al == 8) { +#ifndef BN_SQR_COMBA + BN_ULONG t[16]; + bn_sqr_normal(rr->d, a->d, 8, t); +#else + bn_sqr_comba8(rr->d, a->d); +#endif + } else { +#if defined(BN_RECURSION) + if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) { + BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL * 2]; + bn_sqr_normal(rr->d, a->d, al, t); + } else { + int j, k; + + j = BN_num_bits_word((BN_ULONG)al); + j = 1 << (j - 1); + k = j + j; + if (al == j) { + if (bn_wexpand(tmp, k * 2) == NULL) + goto err; + bn_sqr_recursive(rr->d, a->d, al, tmp->d); + } else { + if (bn_wexpand(tmp, max) == NULL) + goto err; + bn_sqr_normal(rr->d, a->d, al, tmp->d); + } + } +#else + if (bn_wexpand(tmp, max) == NULL) + goto err; + bn_sqr_normal(rr->d, a->d, al, tmp->d); +#endif + } + + rr->neg = 0; + /* + * If the most-significant half of the top word of 'a' is zero, then the + * square of 'a' will max-1 words. + */ + if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l)) + rr->top = max - 1; + else + rr->top = max; + if (rr != r) + BN_copy(r, rr); + ret = 1; + err: + bn_check_top(rr); + bn_check_top(tmp); + BN_CTX_end(ctx); + return (ret); +} + +/* tmp must have 2*n words */ +void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp) +{ + int i, j, max; + const BN_ULONG *ap; + BN_ULONG *rp; + + max = n * 2; + ap = a; + rp = r; + rp[0] = rp[max - 1] = 0; + rp++; + j = n; + + if (--j > 0) { + ap++; + rp[j] = bn_mul_words(rp, ap, j, ap[-1]); + rp += 2; + } + + for (i = n - 2; i > 0; i--) { + j--; + ap++; + rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]); + rp += 2; + } + + bn_add_words(r, r, r, max); + + /* There will not be a carry */ + + bn_sqr_words(tmp, a, n); + + bn_add_words(r, r, tmp, max); +} + +#ifdef BN_RECURSION +/*- + * r is 2*n words in size, + * a and b are both n words in size. (There's not actually a 'b' here ...) + * n must be a power of 2. + * We multiply and return the result. + * t must be 2*n words in size + * We calculate + * a[0]*b[0] + * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0]) + * a[1]*b[1] + */ +void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t) +{ + int n = n2 / 2; + int zero, c1; + BN_ULONG ln, lo, *p; + + if (n2 == 4) { +# ifndef BN_SQR_COMBA + bn_sqr_normal(r, a, 4, t); +# else + bn_sqr_comba4(r, a); +# endif + return; + } else if (n2 == 8) { +# ifndef BN_SQR_COMBA + bn_sqr_normal(r, a, 8, t); +# else + bn_sqr_comba8(r, a); +# endif + return; + } + if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) { + bn_sqr_normal(r, a, n2, t); + return; + } + /* r=(a[0]-a[1])*(a[1]-a[0]) */ + c1 = bn_cmp_words(a, &(a[n]), n); + zero = 0; + if (c1 > 0) + bn_sub_words(t, a, &(a[n]), n); + else if (c1 < 0) + bn_sub_words(t, &(a[n]), a, n); + else + zero = 1; + + /* The result will always be negative unless it is zero */ + p = &(t[n2 * 2]); + + if (!zero) + bn_sqr_recursive(&(t[n2]), t, n, p); + else + memset(&t[n2], 0, sizeof(*t) * n2); + bn_sqr_recursive(r, a, n, p); + bn_sqr_recursive(&(r[n2]), &(a[n]), n, p); + + /*- + * t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) + */ + + c1 = (int)(bn_add_words(t, r, &(r[n2]), n2)); + + /* t[32] is negative */ + c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2)); + + /*- + * t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1]) + * r[10] holds (a[0]*a[0]) + * r[32] holds (a[1]*a[1]) + * c1 holds the carry bits + */ + c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2)); + if (c1) { + p = &(r[n + n2]); + lo = *p; + ln = (lo + c1) & BN_MASK2; + *p = ln; + /* + * The overflow will stop before we over write words we should not + * overwrite + */ + if (ln < (BN_ULONG)c1) { + do { + p++; + lo = *p; + ln = (lo + 1) & BN_MASK2; + *p = ln; + } while (ln == 0); + } + } +} +#endif