X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_add.c;h=7cdefa77a17c57be6892ea650745b63f916e0dec;hp=5d2469123302d58750b9b5c1c250637d395a4b68;hb=f39276fdff6ccc1c71bdb30a8050fa1c0bf6e20a;hpb=dd8dec69b825c9fdafc26a200961702d850496b5 diff --git a/crypto/bn/bn_add.c b/crypto/bn/bn_add.c index 5d24691233..7cdefa77a1 100644 --- a/crypto/bn/bn_add.c +++ b/crypto/bn/bn_add.c @@ -1,307 +1,209 @@ -/* crypto/bn/bn_add.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 can == a or b */ int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) - { - const BIGNUM *tmp; - - bn_check_top(a); - bn_check_top(b); - - /* a + b a+b - * a + -b a-b - * -a + b b-a - * -a + -b -(a+b) - */ - if (a->neg ^ b->neg) - { - /* only one is negative */ - if (a->neg) - { tmp=a; a=b; b=tmp; } - - /* we are now a - b */ - - if (BN_ucmp(a,b) < 0) - { - if (!BN_usub(r,b,a)) return(0); - r->neg=1; - } - else - { - if (!BN_usub(r,a,b)) return(0); - r->neg=0; - } - return(1); - } - - if (a->neg) /* both are neg */ - r->neg=1; - else - r->neg=0; - - if (!BN_uadd(r,a,b)) return(0); - return(1); - } - -/* unsigned add of b to a, r must be large enough */ +{ + int a_neg = a->neg, ret; + + bn_check_top(a); + bn_check_top(b); + + /*- + * a + b a+b + * a + -b a-b + * -a + b b-a + * -a + -b -(a+b) + */ + if (a_neg ^ b->neg) { + /* only one is negative */ + if (a_neg) { + const BIGNUM *tmp; + + tmp = a; + a = b; + b = tmp; + } + + /* we are now a - b */ + + if (BN_ucmp(a, b) < 0) { + if (!BN_usub(r, b, a)) + return 0; + r->neg = 1; + } else { + if (!BN_usub(r, a, b)) + return 0; + r->neg = 0; + } + return 1; + } + + ret = BN_uadd(r, a, b); + r->neg = a_neg; + bn_check_top(r); + return ret; +} + +/* unsigned add of b to a */ int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) - { - register int i; - int max,min; - BN_ULONG *ap,*bp,*rp,carry,t1; - const BIGNUM *tmp; - - bn_check_top(a); - bn_check_top(b); - - if (a->top < b->top) - { tmp=a; a=b; b=tmp; } - max=a->top; - min=b->top; - - if (bn_wexpand(r,max+1) == NULL) - return(0); - - r->top=max; - - - ap=a->d; - bp=b->d; - rp=r->d; - carry=0; - - carry=bn_add_words(rp,ap,bp,min); - rp+=min; - ap+=min; - bp+=min; - i=min; - - if (carry) - { - while (i < max) - { - i++; - t1= *(ap++); - if ((*(rp++)=(t1+1)&BN_MASK2) >= t1) - { - carry=0; - break; - } - } - if ((i >= max) && carry) - { - *(rp++)=1; - r->top++; - } - } - if (rp != ap) - { - for (; itop < b->top) { + const BIGNUM *tmp; + + tmp = a; + a = b; + b = tmp; + } + max = a->top; + min = b->top; + dif = max - min; + + if (bn_wexpand(r, max + 1) == NULL) + return 0; + + r->top = max; + + ap = a->d; + bp = b->d; + rp = r->d; + + carry = bn_add_words(rp, ap, bp, min); + rp += min; + ap += min; + + while (dif) { + dif--; + t1 = *(ap++); + t2 = (t1 + carry) & BN_MASK2; + *(rp++) = t2; + carry &= (t2 == 0); + } + *rp = carry; + r->top += carry; + + r->neg = 0; + bn_check_top(r); + return 1; +} /* unsigned subtraction of b from a, a must be larger than b. */ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) - { - int max,min; - register BN_ULONG t1,t2,*ap,*bp,*rp; - int i,carry; -#if defined(IRIX_CC_BUG) && !defined(LINT) - int dummy; -#endif - - bn_check_top(a); - bn_check_top(b); - - if (a->top < b->top) /* hmm... should not be happening */ - { - BNerr(BN_F_BN_USUB,BN_R_ARG2_LT_ARG3); - return(0); - } - - max=a->top; - min=b->top; - if (bn_wexpand(r,max) == NULL) return(0); - - ap=a->d; - bp=b->d; - rp=r->d; - -#if 1 - carry=0; - for (i=0; i t2) break; - } - } -#if 0 - memcpy(rp,ap,sizeof(*rp)*(max-i)); -#else - if (rp != ap) - { - for (;;) - { - if (i++ >= max) break; - rp[0]=ap[0]; - if (i++ >= max) break; - rp[1]=ap[1]; - if (i++ >= max) break; - rp[2]=ap[2]; - if (i++ >= max) break; - rp[3]=ap[3]; - rp+=4; - ap+=4; - } - } -#endif - - r->top=max; - bn_fix_top(r); - return(1); - } +{ + int max, min, dif; + BN_ULONG t1, t2, borrow, *rp; + const BN_ULONG *ap, *bp; -int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) - { - int max; - int add=0,neg=0; - const BIGNUM *tmp; - - bn_check_top(a); - bn_check_top(b); - - /* a - b a-b - * a - -b a+b - * -a - b -(a+b) - * -a - -b b-a - */ - if (a->neg) - { - if (b->neg) - { tmp=a; a=b; b=tmp; } - else - { add=1; neg=1; } - } - else - { - if (b->neg) { add=1; neg=0; } - } - - if (add) - { - if (!BN_uadd(r,a,b)) return(0); - r->neg=neg; - return(1); - } - - /* We are actually doing a - b :-) */ - - max=(a->top > b->top)?a->top:b->top; - if (bn_wexpand(r,max) == NULL) return(0); - if (BN_ucmp(a,b) < 0) - { - if (!BN_usub(r,b,a)) return(0); - r->neg=1; - } - else - { - if (!BN_usub(r,a,b)) return(0); - r->neg=0; - } - return(1); - } + bn_check_top(a); + bn_check_top(b); + + max = a->top; + min = b->top; + dif = max - min; + + if (dif < 0) { /* hmm... should not be happening */ + BNerr(BN_F_BN_USUB, BN_R_ARG2_LT_ARG3); + return 0; + } + + if (bn_wexpand(r, max) == NULL) + return 0; + + ap = a->d; + bp = b->d; + rp = r->d; + + borrow = bn_sub_words(rp, ap, bp, min); + ap += min; + rp += min; + while (dif) { + dif--; + t1 = *(ap++); + t2 = (t1 - borrow) & BN_MASK2; + *(rp++) = t2; + borrow &= (t1 == 0); + } + + while (max && *--rp == 0) + max--; + + r->top = max; + r->neg = 0; + bn_pollute(r); + + return 1; +} + +int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) +{ + int max; + int add = 0, neg = 0; + + bn_check_top(a); + bn_check_top(b); + + /*- + * a - b a-b + * a - -b a+b + * -a - b -(a+b) + * -a - -b b-a + */ + if (a->neg) { + if (b->neg) { + const BIGNUM *tmp; + + tmp = a; + a = b; + b = tmp; + } else { + add = 1; + neg = 1; + } + } else { + if (b->neg) { + add = 1; + neg = 0; + } + } + + if (add) { + if (!BN_uadd(r, a, b)) + return 0; + r->neg = neg; + return 1; + } + + /* We are actually doing a - b :-) */ + + max = (a->top > b->top) ? a->top : b->top; + if (bn_wexpand(r, max) == NULL) + return 0; + if (BN_ucmp(a, b) < 0) { + if (!BN_usub(r, b, a)) + return 0; + r->neg = 1; + } else { + if (!BN_usub(r, a, b)) + return 0; + r->neg = 0; + } + bn_check_top(r); + return 1; +}