X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_mont.c;h=6d37279a5ea0e7b08f22a660fec1f263709ac942;hp=2f7fb843a95d204d5e688d7b2252b93770da2f09;hb=e8e5597606d10fcb5620399dd751be4ecf3dcd1d;hpb=7c8ced94c32131f24d469d2899f3339f77c47aa1 diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c index 2f7fb843a9..6d37279a5e 100644 --- a/crypto/bn/bn_mont.c +++ b/crypto/bn/bn_mont.c @@ -1,112 +1,10 @@ -/* crypto/bn/bn_mont.c */ -/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) - * 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.] - */ -/* ==================================================================== - * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved. - * - * 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 above 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 acknowledgment: - * "This product includes software developed by the OpenSSL Project - * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" - * - * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to - * endorse or promote products derived from this software without - * prior written permission. For written permission, please contact - * openssl-core@openssl.org. - * - * 5. Products derived from this software may not be called "OpenSSL" - * nor may "OpenSSL" appear in their names without prior written - * permission of the OpenSSL Project. - * - * 6. Redistributions of any form whatsoever must retain the following - * acknowledgment: - * "This product includes software developed by the OpenSSL Project - * for use in the OpenSSL Toolkit (http://www.openssl.org/)" - * - * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY - * EXPRESSED 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 OpenSSL PROJECT OR - * ITS 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. - * ==================================================================== - * - * This product includes cryptographic software written by Eric Young - * (eay@cryptsoft.com). This product includes software written by Tim - * Hudson (tjh@cryptsoft.com). +/* + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. * + * 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 */ /* @@ -116,454 +14,421 @@ * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf */ -#define OPENSSL_FIPSAPI - -#include -#include "cryptlib.h" +#include "internal/cryptlib.h" #include "bn_lcl.h" -#define MONT_WORD /* use the faster word-based algorithm */ +#define MONT_WORD /* use the faster word-based algorithm */ #ifdef MONT_WORD static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); #endif int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, - BN_MONT_CTX *mont, BN_CTX *ctx) - { - BIGNUM *tmp; - int ret=0; + BN_MONT_CTX *mont, BN_CTX *ctx) +{ + BIGNUM *tmp; + int ret = 0; #if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD) - int num = mont->N.top; - - if (num>1 && a->top==num && b->top==num) - { - if (bn_wexpand(r,num) == NULL) return(0); - if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num)) - { - r->neg = a->neg^b->neg; - r->top = num; - bn_correct_top(r); - return(1); - } - } + int num = mont->N.top; + + if (num > 1 && a->top == num && b->top == num) { + if (bn_wexpand(r, num) == NULL) + return (0); + if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) { + r->neg = a->neg ^ b->neg; + r->top = num; + bn_correct_top(r); + return (1); + } + } #endif - BN_CTX_start(ctx); - tmp = BN_CTX_get(ctx); - if (tmp == NULL) goto err; - - bn_check_top(tmp); - if (a == b) - { - if (!BN_sqr(tmp,a,ctx)) goto err; - } - else - { - if (!BN_mul(tmp,a,b,ctx)) goto err; - } - /* reduce from aRR to aR */ + BN_CTX_start(ctx); + tmp = BN_CTX_get(ctx); + if (tmp == NULL) + goto err; + + bn_check_top(tmp); + if (a == b) { + if (!BN_sqr(tmp, a, ctx)) + goto err; + } else { + if (!BN_mul(tmp, a, b, ctx)) + goto err; + } + /* reduce from aRR to aR */ #ifdef MONT_WORD - if (!BN_from_montgomery_word(r,tmp,mont)) goto err; + if (!BN_from_montgomery_word(r, tmp, mont)) + goto err; #else - if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err; + if (!BN_from_montgomery(r, tmp, mont, ctx)) + goto err; #endif - bn_check_top(r); - ret=1; -err: - BN_CTX_end(ctx); - return(ret); - } + bn_check_top(r); + ret = 1; + err: + BN_CTX_end(ctx); + return (ret); +} #ifdef MONT_WORD static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) - { - BIGNUM *n; - BN_ULONG *ap,*np,*rp,n0,v,*nrp; - int al,nl,max,i,x,ri; - - n= &(mont->N); - /* mont->ri is the size of mont->N in bits (rounded up - to the word size) */ - al=ri=mont->ri/BN_BITS2; - - nl=n->top; - if ((al == 0) || (nl == 0)) { ret->top=0; return(1); } - - max=(nl+al+1); /* allow for overflow (no?) XXX */ - if (bn_wexpand(r,max) == NULL) return(0); - - r->neg^=n->neg; - np=n->d; - rp=r->d; - nrp= &(r->d[nl]); - - /* clear the top words of T */ -#if 1 - for (i=r->top; id[i]=0; -#else - memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); -#endif - - r->top=max; - n0=mont->n0[0]; - -#ifdef BN_COUNT - fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl); -#endif - for (i=0; i= v) - continue; - else - { - if (((++nrp[0])&BN_MASK2) != 0) continue; - if (((++nrp[1])&BN_MASK2) != 0) continue; - for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ; - } - } - bn_correct_top(r); - - /* mont->ri will be a multiple of the word size and below code - * is kind of BN_rshift(ret,r,mont->ri) equivalent */ - if (r->top <= ri) - { - ret->top=0; - return(1); - } - al=r->top-ri; - -#define BRANCH_FREE 1 -#if BRANCH_FREE - if (bn_wexpand(ret,ri) == NULL) return(0); - x=0-(((al-ri)>>(sizeof(al)*8-1))&1); - ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */ - ret->neg=r->neg; - - rp=ret->d; - ap=&(r->d[ri]); - - { - size_t m1,m2; - - v=bn_sub_words(rp,ap,np,ri); - /* this ----------------^^ works even in alri) nrp=rp; else nrp=ap; */ - /* in other words if subtraction result is real, then - * trick unconditional memcpy below to perform in-place - * "refresh" instead of actual copy. */ - m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al>(sizeof(al)*8-1))&1); /* al>ri */ - m1|=m2; /* (al!=ri) */ - m1|=(0-(size_t)v); /* (al!=ri || v) */ - m1&=~m2; /* (al!=ri || v) && !al>ri */ - nrp=(BN_ULONG *)(((size_t)rp&~m1)|((size_t)ap&m1)); - } - - /* 'itop=al; - ret->neg=r->neg; - - rp=ret->d; - ap=&(r->d[ri]); - al-=4; - for (i=0; iN)) >= 0) - { - if (!BN_usub(ret,ret,&(mont->N))) return(0); - } -#endif - bn_check_top(ret); - - return(1); - } -#endif /* MONT_WORD */ +{ + BIGNUM *n; + BN_ULONG *ap, *np, *rp, n0, v, carry; + int nl, max, i; + + n = &(mont->N); + nl = n->top; + if (nl == 0) { + ret->top = 0; + return (1); + } + + max = (2 * nl); /* carry is stored separately */ + if (bn_wexpand(r, max) == NULL) + return (0); + + r->neg ^= n->neg; + np = n->d; + rp = r->d; + + /* clear the top words of T */ + i = max - r->top; + if (i) + memset(&rp[r->top], 0, sizeof(*rp) * i); + + r->top = max; + n0 = mont->n0[0]; + + for (carry = 0, i = 0; i < nl; i++, rp++) { + v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2); + v = (v + carry + rp[nl]) & BN_MASK2; + carry |= (v != rp[nl]); + carry &= (v <= rp[nl]); + rp[nl] = v; + } + + if (bn_wexpand(ret, nl) == NULL) + return (0); + ret->top = nl; + ret->neg = r->neg; + + rp = ret->d; + ap = &(r->d[nl]); + +# define BRANCH_FREE 1 +# if BRANCH_FREE + { + BN_ULONG *nrp; + size_t m; + + v = bn_sub_words(rp, ap, np, nl) - carry; + /* + * if subtraction result is real, then trick unconditional memcpy + * below to perform in-place "refresh" instead of actual copy. + */ + m = (0 - (size_t)v); + nrp = + (BN_ULONG *)(((PTR_SIZE_INT) rp & ~m) | ((PTR_SIZE_INT) ap & m)); + + for (i = 0, nl -= 4; i < nl; i += 4) { + BN_ULONG t1, t2, t3, t4; + + t1 = nrp[i + 0]; + t2 = nrp[i + 1]; + t3 = nrp[i + 2]; + ap[i + 0] = 0; + t4 = nrp[i + 3]; + ap[i + 1] = 0; + rp[i + 0] = t1; + ap[i + 2] = 0; + rp[i + 1] = t2; + ap[i + 3] = 0; + rp[i + 2] = t3; + rp[i + 3] = t4; + } + for (nl += 4; i < nl; i++) + rp[i] = nrp[i], ap[i] = 0; + } +# else + if (bn_sub_words(rp, ap, np, nl) - carry) + memcpy(rp, ap, nl * sizeof(BN_ULONG)); +# endif + bn_correct_top(r); + bn_correct_top(ret); + bn_check_top(ret); + + return (1); +} +#endif /* MONT_WORD */ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, - BN_CTX *ctx) - { - int retn=0; + BN_CTX *ctx) +{ + int retn = 0; #ifdef MONT_WORD - BIGNUM *t; - - BN_CTX_start(ctx); - if ((t = BN_CTX_get(ctx)) && BN_copy(t,a)) - retn = BN_from_montgomery_word(ret,t,mont); - BN_CTX_end(ctx); -#else /* !MONT_WORD */ - BIGNUM *t1,*t2; - - BN_CTX_start(ctx); - t1 = BN_CTX_get(ctx); - t2 = BN_CTX_get(ctx); - if (t1 == NULL || t2 == NULL) goto err; - - if (!BN_copy(t1,a)) goto err; - BN_mask_bits(t1,mont->ri); - - if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err; - BN_mask_bits(t2,mont->ri); - - if (!BN_mul(t1,t2,&mont->N,ctx)) goto err; - if (!BN_add(t2,a,t1)) goto err; - if (!BN_rshift(ret,t2,mont->ri)) goto err; - - if (BN_ucmp(ret, &(mont->N)) >= 0) - { - if (!BN_usub(ret,ret,&(mont->N))) goto err; - } - retn=1; - bn_check_top(ret); + BIGNUM *t; + + BN_CTX_start(ctx); + if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) + retn = BN_from_montgomery_word(ret, t, mont); + BN_CTX_end(ctx); +#else /* !MONT_WORD */ + BIGNUM *t1, *t2; + + BN_CTX_start(ctx); + t1 = BN_CTX_get(ctx); + t2 = BN_CTX_get(ctx); + if (t1 == NULL || t2 == NULL) + goto err; + + if (!BN_copy(t1, a)) + goto err; + BN_mask_bits(t1, mont->ri); + + if (!BN_mul(t2, t1, &mont->Ni, ctx)) + goto err; + BN_mask_bits(t2, mont->ri); + + if (!BN_mul(t1, t2, &mont->N, ctx)) + goto err; + if (!BN_add(t2, a, t1)) + goto err; + if (!BN_rshift(ret, t2, mont->ri)) + goto err; + + if (BN_ucmp(ret, &(mont->N)) >= 0) { + if (!BN_usub(ret, ret, &(mont->N))) + goto err; + } + retn = 1; + bn_check_top(ret); err: - BN_CTX_end(ctx); -#endif /* MONT_WORD */ - return(retn); - } + BN_CTX_end(ctx); +#endif /* MONT_WORD */ + return (retn); +} BN_MONT_CTX *BN_MONT_CTX_new(void) - { - BN_MONT_CTX *ret; +{ + BN_MONT_CTX *ret; - if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL) - return(NULL); + if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) + return (NULL); - BN_MONT_CTX_init(ret); - ret->flags=BN_FLG_MALLOCED; - return(ret); - } + BN_MONT_CTX_init(ret); + ret->flags = BN_FLG_MALLOCED; + return (ret); +} void BN_MONT_CTX_init(BN_MONT_CTX *ctx) - { - ctx->ri=0; - BN_init(&(ctx->RR)); - BN_init(&(ctx->N)); - BN_init(&(ctx->Ni)); - ctx->n0[0] = ctx->n0[1] = 0; - ctx->flags=0; - } +{ + ctx->ri = 0; + bn_init(&(ctx->RR)); + bn_init(&(ctx->N)); + bn_init(&(ctx->Ni)); + ctx->n0[0] = ctx->n0[1] = 0; + ctx->flags = 0; +} void BN_MONT_CTX_free(BN_MONT_CTX *mont) - { - if(mont == NULL) - return; +{ + if (mont == NULL) + return; - BN_free(&(mont->RR)); - BN_free(&(mont->N)); - BN_free(&(mont->Ni)); - if (mont->flags & BN_FLG_MALLOCED) - OPENSSL_free(mont); - } + BN_clear_free(&(mont->RR)); + BN_clear_free(&(mont->N)); + BN_clear_free(&(mont->Ni)); + if (mont->flags & BN_FLG_MALLOCED) + OPENSSL_free(mont); +} int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) - { - int ret = 0; - BIGNUM *Ri,*R; +{ + int ret = 0; + BIGNUM *Ri, *R; + + if (BN_is_zero(mod)) + return 0; - BN_CTX_start(ctx); - if((Ri = BN_CTX_get(ctx)) == NULL) goto err; - R= &(mont->RR); /* grab RR as a temp */ - if (!BN_copy(&(mont->N),mod)) goto err; /* Set N */ - mont->N.neg = 0; + BN_CTX_start(ctx); + if ((Ri = BN_CTX_get(ctx)) == NULL) + goto err; + R = &(mont->RR); /* grab RR as a temp */ + if (!BN_copy(&(mont->N), mod)) + goto err; /* Set N */ + mont->N.neg = 0; #ifdef MONT_WORD - { - BIGNUM tmod; - BN_ULONG buf[2]; - - BN_init(&tmod); - tmod.d=buf; - tmod.dmax=2; - tmod.neg=0; - - mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2; - -#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) - /* Only certain BN_BITS2<=32 platforms actually make use of - * n0[1], and we could use the #else case (with a shorter R - * value) for the others. However, currently only the assembler - * files do know which is which. */ - - BN_zero(R); - if (!(BN_set_bit(R,2*BN_BITS2))) goto err; - - tmod.top=0; - if ((buf[0] = mod->d[0])) tmod.top=1; - if ((buf[1] = mod->top>1 ? mod->d[1] : 0)) tmod.top=2; - - if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) - goto err; - if (!BN_lshift(Ri,Ri,2*BN_BITS2)) goto err; /* R*Ri */ - if (!BN_is_zero(Ri)) - { - if (!BN_sub_word(Ri,1)) goto err; - } - else /* if N mod word size == 1 */ - { - if (bn_expand(Ri,(int)sizeof(BN_ULONG)*2) == NULL) - goto err; - /* Ri-- (mod double word size) */ - Ri->neg=0; - Ri->d[0]=BN_MASK2; - Ri->d[1]=BN_MASK2; - Ri->top=2; - } - if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; - /* Ni = (R*Ri-1)/N, - * keep only couple of least significant words: */ - mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; - mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0; -#else - BN_zero(R); - if (!(BN_set_bit(R,BN_BITS2))) goto err; /* R */ - - buf[0]=mod->d[0]; /* tmod = N mod word size */ - buf[1]=0; - tmod.top = buf[0] != 0 ? 1 : 0; - /* Ri = R^-1 mod N*/ - if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) - goto err; - if (!BN_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */ - if (!BN_is_zero(Ri)) - { - if (!BN_sub_word(Ri,1)) goto err; - } - else /* if N mod word size == 1 */ - { - if (!BN_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */ - } - if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; - /* Ni = (R*Ri-1)/N, - * keep only least significant word: */ - mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; - mont->n0[1] = 0; -#endif - } -#else /* !MONT_WORD */ - { /* bignum version */ - mont->ri=BN_num_bits(&mont->N); - BN_zero(R); - if (!BN_set_bit(R,mont->ri)) goto err; /* R = 2^ri */ - /* Ri = R^-1 mod N*/ - if ((BN_mod_inverse(Ri,R,&mont->N,ctx)) == NULL) - goto err; - if (!BN_lshift(Ri,Ri,mont->ri)) goto err; /* R*Ri */ - if (!BN_sub_word(Ri,1)) goto err; - /* Ni = (R*Ri-1) / N */ - if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err; - } + { + BIGNUM tmod; + BN_ULONG buf[2]; + + bn_init(&tmod); + tmod.d = buf; + tmod.dmax = 2; + tmod.neg = 0; + + mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2; + +# if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) + /* + * Only certain BN_BITS2<=32 platforms actually make use of n0[1], + * and we could use the #else case (with a shorter R value) for the + * others. However, currently only the assembler files do know which + * is which. + */ + + BN_zero(R); + if (!(BN_set_bit(R, 2 * BN_BITS2))) + goto err; + + tmod.top = 0; + if ((buf[0] = mod->d[0])) + tmod.top = 1; + if ((buf[1] = mod->top > 1 ? mod->d[1] : 0)) + tmod.top = 2; + + if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL) + goto err; + if (!BN_lshift(Ri, Ri, 2 * BN_BITS2)) + goto err; /* R*Ri */ + if (!BN_is_zero(Ri)) { + if (!BN_sub_word(Ri, 1)) + goto err; + } else { /* if N mod word size == 1 */ + + if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL) + goto err; + /* Ri-- (mod double word size) */ + Ri->neg = 0; + Ri->d[0] = BN_MASK2; + Ri->d[1] = BN_MASK2; + Ri->top = 2; + } + if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) + goto err; + /* + * Ni = (R*Ri-1)/N, keep only couple of least significant words: + */ + mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; + mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0; +# else + BN_zero(R); + if (!(BN_set_bit(R, BN_BITS2))) + goto err; /* R */ + + buf[0] = mod->d[0]; /* tmod = N mod word size */ + buf[1] = 0; + tmod.top = buf[0] != 0 ? 1 : 0; + /* Ri = R^-1 mod N */ + if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL) + goto err; + if (!BN_lshift(Ri, Ri, BN_BITS2)) + goto err; /* R*Ri */ + if (!BN_is_zero(Ri)) { + if (!BN_sub_word(Ri, 1)) + goto err; + } else { /* if N mod word size == 1 */ + + if (!BN_set_word(Ri, BN_MASK2)) + goto err; /* Ri-- (mod word size) */ + } + if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) + goto err; + /* + * Ni = (R*Ri-1)/N, keep only least significant word: + */ + mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; + mont->n0[1] = 0; +# endif + } +#else /* !MONT_WORD */ + { /* bignum version */ + mont->ri = BN_num_bits(&mont->N); + BN_zero(R); + if (!BN_set_bit(R, mont->ri)) + goto err; /* R = 2^ri */ + /* Ri = R^-1 mod N */ + if ((BN_mod_inverse(Ri, R, &mont->N, ctx)) == NULL) + goto err; + if (!BN_lshift(Ri, Ri, mont->ri)) + goto err; /* R*Ri */ + if (!BN_sub_word(Ri, 1)) + goto err; + /* + * Ni = (R*Ri-1) / N + */ + if (!BN_div(&(mont->Ni), NULL, Ri, &mont->N, ctx)) + goto err; + } #endif - /* setup RR for conversions */ - BN_zero(&(mont->RR)); - if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err; - if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err; + /* setup RR for conversions */ + BN_zero(&(mont->RR)); + if (!BN_set_bit(&(mont->RR), mont->ri * 2)) + goto err; + if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx)) + goto err; - ret = 1; -err: - BN_CTX_end(ctx); - return ret; - } + ret = 1; + err: + BN_CTX_end(ctx); + return ret; +} BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) - { - if (to == from) return(to); - - if (!BN_copy(&(to->RR),&(from->RR))) return NULL; - if (!BN_copy(&(to->N),&(from->N))) return NULL; - if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL; - to->ri=from->ri; - to->n0[0]=from->n0[0]; - 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; - } +{ + if (to == from) + return (to); + + if (!BN_copy(&(to->RR), &(from->RR))) + return NULL; + if (!BN_copy(&(to->N), &(from->N))) + return NULL; + if (!BN_copy(&(to->Ni), &(from->Ni))) + return NULL; + to->ri = from->ri; + to->n0[0] = from->n0[0]; + to->n0[1] = from->n0[1]; + return (to); +} + +BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_RWLOCK *lock, + const BIGNUM *mod, BN_CTX *ctx) +{ + BN_MONT_CTX *ret; + + CRYPTO_THREAD_read_lock(lock); + ret = *pmont; + CRYPTO_THREAD_unlock(lock); + if (ret) + return ret; + + /* + * We don't want to serialise globally while doing our lazy-init math in + * BN_MONT_CTX_set. That punishes threads that are doing independent + * things. Instead, punish the case where more than one thread tries to + * lazy-init the same 'pmont', by having each do the lazy-init math work + * independently and only use the one from the thread that wins the race + * (the losers throw away the work they've done). + */ + ret = BN_MONT_CTX_new(); + if (ret == NULL) + return NULL; + if (!BN_MONT_CTX_set(ret, mod, ctx)) { + BN_MONT_CTX_free(ret); + return NULL; + } + + /* The locked compare-and-set, after the local work is done. */ + CRYPTO_THREAD_write_lock(lock); + if (*pmont) { + BN_MONT_CTX_free(ret); + ret = *pmont; + } else + *pmont = ret; + CRYPTO_THREAD_unlock(lock); + return ret; +}