511 lines
14 KiB
C
511 lines
14 KiB
C
/* crypto/bn/bn_mont.c */
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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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/* ====================================================================
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* Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
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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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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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/*
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* Details about Montgomery multiplication algorithms can be found at
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* http://security.ece.orst.edu/publications.html, e.g.
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* http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
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* sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
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*/
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#include <stdio.h>
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#include "cryptlib.h"
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#include "bn_lcl.h"
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#define MONT_WORD /* use the faster word-based algorithm */
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#ifdef MONT_WORD
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static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
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#endif
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int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
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BN_MONT_CTX *mont, BN_CTX *ctx)
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{
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BIGNUM *tmp;
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int ret=0;
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#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD)
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int num = mont->N.top;
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if (num>1 && a->top==num && b->top==num)
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{
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if (bn_wexpand(r,num) == NULL) return(0);
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if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num))
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{
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r->neg = a->neg^b->neg;
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r->top = num;
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bn_correct_top(r);
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return(1);
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}
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}
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#endif
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BN_CTX_start(ctx);
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tmp = BN_CTX_get(ctx);
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if (tmp == NULL) goto err;
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bn_check_top(tmp);
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if (a == b)
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{
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if (!BN_sqr(tmp,a,ctx)) goto err;
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}
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else
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{
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if (!BN_mul(tmp,a,b,ctx)) goto err;
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}
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/* reduce from aRR to aR */
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#ifdef MONT_WORD
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if (!BN_from_montgomery_word(r,tmp,mont)) goto err;
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#else
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if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
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#endif
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bn_check_top(r);
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ret=1;
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err:
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BN_CTX_end(ctx);
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return(ret);
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}
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#ifdef MONT_WORD
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static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
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{
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BIGNUM *n;
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BN_ULONG *ap,*np,*rp,n0,v,*nrp;
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int al,nl,max,i,x,ri;
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n= &(mont->N);
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/* mont->ri is the size of mont->N in bits (rounded up
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to the word size) */
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al=ri=mont->ri/BN_BITS2;
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nl=n->top;
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if ((al == 0) || (nl == 0)) { ret->top=0; return(1); }
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max=(nl+al+1); /* allow for overflow (no?) XXX */
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if (bn_wexpand(r,max) == NULL) return(0);
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r->neg^=n->neg;
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np=n->d;
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rp=r->d;
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nrp= &(r->d[nl]);
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/* clear the top words of T */
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#if 1
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for (i=r->top; i<max; i++) /* memset? XXX */
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r->d[i]=0;
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#else
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memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
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#endif
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r->top=max;
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n0=mont->n0[0];
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#ifdef BN_COUNT
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fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl);
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#endif
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for (i=0; i<nl; i++)
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{
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#ifdef __TANDEM
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{
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long long t1;
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long long t2;
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long long t3;
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t1 = rp[0] * (n0 & 0177777);
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t2 = 037777600000l;
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t2 = n0 & t2;
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t3 = rp[0] & 0177777;
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t2 = (t3 * t2) & BN_MASK2;
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t1 = t1 + t2;
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v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
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}
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#else
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v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
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#endif
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nrp++;
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rp++;
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if (((nrp[-1]+=v)&BN_MASK2) >= v)
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continue;
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else
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{
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if (((++nrp[0])&BN_MASK2) != 0) continue;
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if (((++nrp[1])&BN_MASK2) != 0) continue;
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for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
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}
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}
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bn_correct_top(r);
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/* mont->ri will be a multiple of the word size */
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#if 0
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BN_rshift(ret,r,mont->ri);
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#else
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if (r->top < ri)
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{
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ret->top=0;
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return(1);
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}
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al=r->top-ri;
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if (bn_wexpand(ret,al) == NULL) return(0);
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ret->neg=r->neg;
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ret->top=al;
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rp=ret->d;
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ap=&(r->d[ri]);
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al-=4;
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for (i=0; i<al; i+=4)
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{
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BN_ULONG t1,t2,t3,t4;
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t1=ap[i+0];
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t2=ap[i+1];
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t3=ap[i+2];
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t4=ap[i+3];
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rp[i+0]=t1;
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rp[i+1]=t2;
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rp[i+2]=t3;
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rp[i+3]=t4;
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}
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al+=4;
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for (; i<al; i++)
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rp[i]=ap[i];
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#endif
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if (BN_ucmp(ret, &(mont->N)) >= 0)
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{
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if (!BN_usub(ret,ret,&(mont->N))) return(0);
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}
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bn_check_top(ret);
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return(1);
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}
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#endif /* MONT_WORD */
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int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
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BN_CTX *ctx)
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{
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int retn=0;
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#ifdef MONT_WORD
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BIGNUM *t;
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BN_CTX_start(ctx);
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if ((t = BN_CTX_get(ctx)) && BN_copy(t,a))
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retn = BN_from_montgomery_word(ret,t,mont);
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BN_CTX_end(ctx);
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#else /* !MONT_WORD */
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BIGNUM *t1,*t2;
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BN_CTX_start(ctx);
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t1 = BN_CTX_get(ctx);
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t2 = BN_CTX_get(ctx);
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if (t1 == NULL || t2 == NULL) goto err;
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if (!BN_copy(t1,a)) goto err;
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BN_mask_bits(t1,mont->ri);
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if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
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BN_mask_bits(t2,mont->ri);
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if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
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if (!BN_add(t2,a,t1)) goto err;
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if (!BN_rshift(ret,t2,mont->ri)) goto err;
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if (BN_ucmp(ret, &(mont->N)) >= 0)
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{
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if (!BN_usub(ret,ret,&(mont->N))) goto err;
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}
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retn=1;
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bn_check_top(ret);
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err:
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BN_CTX_end(ctx);
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#endif /* MONT_WORD */
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return(retn);
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}
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BN_MONT_CTX *BN_MONT_CTX_new(void)
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{
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BN_MONT_CTX *ret;
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if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL)
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return(NULL);
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BN_MONT_CTX_init(ret);
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ret->flags=BN_FLG_MALLOCED;
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return(ret);
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}
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void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
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{
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ctx->ri=0;
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BN_init(&(ctx->RR));
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BN_init(&(ctx->N));
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BN_init(&(ctx->Ni));
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ctx->flags=0;
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}
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void BN_MONT_CTX_free(BN_MONT_CTX *mont)
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{
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if(mont == NULL)
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return;
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BN_free(&(mont->RR));
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BN_free(&(mont->N));
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BN_free(&(mont->Ni));
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if (mont->flags & BN_FLG_MALLOCED)
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OPENSSL_free(mont);
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}
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int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
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{
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int ret = 0;
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BIGNUM *Ri,*R;
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BN_CTX_start(ctx);
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if((Ri = BN_CTX_get(ctx)) == NULL) goto err;
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R= &(mont->RR); /* grab RR as a temp */
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if (!BN_copy(&(mont->N),mod)) goto err; /* Set N */
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mont->N.neg = 0;
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#ifdef MONT_WORD
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{
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BIGNUM tmod;
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BN_ULONG buf[2];
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tmod.d=buf;
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tmod.dmax=2;
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tmod.neg=0;
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mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
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#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
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BN_zero(R);
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if (!(BN_set_bit(R,2*BN_BITS2))) goto err;
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tmod.top=0;
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if ((buf[0] = mod->d[0])) tmod.top=1;
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if ((buf[1] = mod->top>1 ? mod->d[1] : 0)) tmod.top=2;
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if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL)
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goto err;
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if (!BN_lshift(Ri,Ri,2*BN_BITS2)) goto err; /* R*Ri */
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if (!BN_is_zero(Ri))
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{
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if (!BN_sub_word(Ri,1)) goto err;
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}
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else /* if N mod word size == 1 */
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{
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if (bn_expand(Ri,(int)sizeof(BN_ULONG)*2) == NULL)
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goto err;
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/* Ri-- (mod double word size) */
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Ri->neg=0;
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Ri->d[0]=BN_MASK2;
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Ri->d[1]=BN_MASK2;
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Ri->top=2;
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}
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if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err;
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/* Ni = (R*Ri-1)/N,
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* keep only couple of least significant words: */
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mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
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mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;
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#else
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BN_zero(R);
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if (!(BN_set_bit(R,BN_BITS2))) goto err; /* R */
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buf[0]=mod->d[0]; /* tmod = N mod word size */
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buf[1]=0;
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tmod.top = buf[0] != 0 ? 1 : 0;
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/* Ri = R^-1 mod N*/
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if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL)
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goto err;
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if (!BN_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */
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if (!BN_is_zero(Ri))
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{
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if (!BN_sub_word(Ri,1)) goto err;
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}
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else /* if N mod word size == 1 */
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{
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if (!BN_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */
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}
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if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err;
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/* Ni = (R*Ri-1)/N,
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* keep only least significant word: */
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mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
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mont->n0[1] = 0;
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#endif
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}
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#else /* !MONT_WORD */
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{ /* bignum version */
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mont->ri=BN_num_bits(&mont->N);
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BN_zero(R);
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if (!BN_set_bit(R,mont->ri)) goto err; /* R = 2^ri */
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/* Ri = R^-1 mod N*/
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if ((BN_mod_inverse(Ri,R,&mont->N,ctx)) == NULL)
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goto err;
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if (!BN_lshift(Ri,Ri,mont->ri)) goto err; /* R*Ri */
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if (!BN_sub_word(Ri,1)) goto err;
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/* Ni = (R*Ri-1) / N */
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if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err;
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}
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#endif
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/* setup RR for conversions */
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BN_zero(&(mont->RR));
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if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err;
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if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err;
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ret = 1;
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err:
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BN_CTX_end(ctx);
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return ret;
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}
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BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
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{
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if (to == from) return(to);
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if (!BN_copy(&(to->RR),&(from->RR))) return NULL;
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if (!BN_copy(&(to->N),&(from->N))) return NULL;
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if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL;
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to->ri=from->ri;
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to->n0[0]=from->n0[0];
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to->n0[1]=from->n0[1];
|
|
return(to);
|
|
}
|
|
|
|
BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock,
|
|
const BIGNUM *mod, BN_CTX *ctx)
|
|
{
|
|
int got_write_lock = 0;
|
|
BN_MONT_CTX *ret;
|
|
|
|
CRYPTO_r_lock(lock);
|
|
if (!*pmont)
|
|
{
|
|
CRYPTO_r_unlock(lock);
|
|
CRYPTO_w_lock(lock);
|
|
got_write_lock = 1;
|
|
|
|
if (!*pmont)
|
|
{
|
|
ret = BN_MONT_CTX_new();
|
|
if (ret && !BN_MONT_CTX_set(ret, mod, ctx))
|
|
BN_MONT_CTX_free(ret);
|
|
else
|
|
*pmont = ret;
|
|
}
|
|
}
|
|
|
|
ret = *pmont;
|
|
|
|
if (got_write_lock)
|
|
CRYPTO_w_unlock(lock);
|
|
else
|
|
CRYPTO_r_unlock(lock);
|
|
|
|
return ret;
|
|
}
|