-/* crypto/bn/bn_mont.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
*/
/*
- * Details about Montgomery multiplication algorithms can be found at:
- * http://www.ece.orst.edu/ISL/Publications.html
- * http://www.ece.orst.edu/ISL/Koc/papers/j37acmon.pdf
+ * Details about Montgomery multiplication algorithms can be found at
+ * http://security.ece.orst.edu/publications.html, e.g.
+ * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
+ * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
*/
-#include <stdio.h>
-#include "cryptlib.h"
+#include "internal/cryptlib.h"
#include "bn_lcl.h"
-#define MONT_WORD
-
-int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_MONT_CTX *mont,
- BN_CTX *ctx)
- {
- BIGNUM *tmp,*tmp2;
-
- tmp= &(ctx->bn[ctx->tos]);
- tmp2= &(ctx->bn[ctx->tos]);
- ctx->tos+=2;
-
- bn_check_top(tmp);
- bn_check_top(tmp2);
-
- if (a == b)
- {
-#if 0
- bn_wexpand(tmp,a->top*2);
- bn_wexpand(tmp2,a->top*4);
- bn_sqr_recursive(tmp->d,a->d,a->top,tmp2->d);
- tmp->top=a->top*2;
- if (tmp->d[tmp->top-1] == 0)
- tmp->top--;
-#else
- if (!BN_sqr(tmp,a,ctx)) goto err;
-#endif
- }
- else
- {
- if (!BN_mul(tmp,a,b,ctx)) goto err;
- }
- /* reduce from aRR to aR */
- if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
- ctx->tos-=2;
- return(1);
-err:
- return(0);
- }
-
-int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont,
- BN_CTX *ctx)
- {
-#ifdef BN_RECURSION_MONT
- if (mont->use_word)
-#endif
- {
- BIGNUM *n,*r;
- BN_ULONG *ap,*np,*rp,n0,v,*nrp;
- int al,nl,max,i,x,ri;
- int retn=0;
-
- r= &(ctx->bn[ctx->tos]);
-
- if (!BN_copy(r,a)) goto err1;
- n= &(mont->N);
-
- ap=a->d;
- /* mont->ri is the size of mont->N in bits/words */
- al=ri=mont->ri/BN_BITS2;
+#define MONT_WORD /* use the faster word-based algorithm */
- nl=n->top;
- if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
-
- max=(nl+al+1); /* allow for overflow (no?) XXX */
- if (bn_wexpand(r,max) == NULL) goto err1;
- if (bn_wexpand(ret,max) == NULL) goto err1;
-
- r->neg=a->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; i<max; i++) /* memset? XXX */
- r->d[i]=0;
-#else
- memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
+#ifdef MONT_WORD
+static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
#endif
- r->top=max;
- n0=mont->n0;
-
-#ifdef BN_COUNT
-printf("word BN_from_montgomery %d * %d\n",nl,nl);
-#endif
- for (i=0; i<nl; i++)
- {
- v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
- nrp++;
- rp++;
- if (((nrp[-1]+=v)&BN_MASK2) >= 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_fix_top(r);
-
- /* mont->ri will be a multiple of the word size */
-#if 0
- BN_rshift(ret,r,mont->ri);
-#else
- x=ri;
- rp=ret->d;
- ap= &(r->d[x]);
- if (r->top < x)
- al=0;
- else
- al=r->top-x;
- ret->top=al;
- al-=4;
- for (i=0; i<al; i+=4)
- {
- BN_ULONG t1,t2,t3,t4;
-
- t1=ap[i+0];
- t2=ap[i+1];
- t3=ap[i+2];
- t4=ap[i+3];
- rp[i+0]=t1;
- rp[i+1]=t2;
- rp[i+2]=t3;
- rp[i+3]=t4;
- }
- al+=4;
- for (; i<al; i++)
- rp[i]=ap[i];
+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;
+#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);
+ }
+ }
#endif
- if (BN_ucmp(ret, &(mont->N)) >= 0)
- {
- BN_usub(ret,ret,&(mont->N)); /* XXX */
- }
- retn=1;
-err1:
- return(retn);
- }
-#ifdef BN_RECURSION_MONT
- else /* bignum version */
- {
- BIGNUM *t1,*t2,*t3;
- int j,i;
-
-#ifdef BN_COUNT
-printf("number BN_from_montgomery\n");
-#endif
-
- t1= &(ctx->bn[ctx->tos]);
- t2= &(ctx->bn[ctx->tos+1]);
- t3= &(ctx->bn[ctx->tos+2]);
-
- i=mont->Ni.top;
- bn_wexpand(ret,i); /* perhaps only i*2 */
- bn_wexpand(t1,i*4); /* perhaps only i*2 */
- bn_wexpand(t2,i*2); /* perhaps only i */
-
- bn_mul_low_recursive(t2->d,a->d,mont->Ni.d,i,t1->d);
-
- BN_zero(t3);
- BN_set_bit(t3,mont->N.top*BN_BITS2);
- bn_sub_words(t3->d,t3->d,a->d,i);
- bn_mul_high(ret->d,t2->d,mont->N.d,t3->d,i,t1->d);
-
- /* hmm... if a is between i and 2*i, things are bad */
- if (a->top > i)
- {
- j=(int)(bn_add_words(ret->d,ret->d,&(a->d[i]),i));
- if (j) /* overflow */
- bn_sub_words(ret->d,ret->d,mont->N.d,i);
- }
- ret->top=i;
- bn_fix_top(ret);
- if (a->d[0])
- BN_add_word(ret,1); /* Always? */
- else /* Very very rare */
- {
- for (i=1; i<mont->N.top-1; i++)
- {
- if (a->d[i])
- {
- BN_add_word(ret,1); /* Always? */
- break;
- }
- }
- }
-
- if (BN_ucmp(ret,&(mont->N)) >= 0)
- BN_usub(ret,ret,&(mont->N));
-
- return(1);
- }
+ 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;
+#else
+ if (!BN_from_montgomery(r, tmp, mont, ctx))
+ goto err;
#endif
- }
+ 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, 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;
+#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);
+ err:
+ 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 *)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->use_word=0;
- ctx->ri=0;
- BN_init(&(ctx->RR));
- BN_init(&(ctx->N));
- BN_init(&(ctx->Ni));
- 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;
-
- BN_free(&(mont->RR));
- BN_free(&(mont->N));
- BN_free(&(mont->Ni));
- if (mont->flags & BN_FLG_MALLOCED)
- Free(mont);
- }
-
-int BN_MONT_CTX_set(BN_MONT_CTX *mont, BIGNUM *mod, BN_CTX *ctx)
- {
- BIGNUM Ri,*R;
-
- BN_init(&Ri);
- R= &(mont->RR); /* grab RR as a temp */
- BN_copy(&(mont->N),mod); /* Set N */
-
-#ifdef BN_RECURSION_MONT
- if (mont->N.top < BN_MONT_CTX_SET_SIZE_WORD)
-#endif
- {
- BIGNUM tmod;
- BN_ULONG buf[2];
-
- mont->use_word=1;
-
- mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
- BN_zero(R);
- BN_set_bit(R,BN_BITS2);
- /* I was bad, this modification of a passed variable was
- * breaking the multithreaded stuff :-(
- * z=mod->top;
- * mod->top=1; */
-
- buf[0]=mod->d[0];
- buf[1]=0;
- tmod.d=buf;
- tmod.top=1;
- tmod.max=mod->max;
- tmod.neg=mod->neg;
-
- if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL)
- goto err;
- BN_lshift(&Ri,&Ri,BN_BITS2); /* R*Ri */
- if (!BN_is_zero(&Ri))
- {
-#if 1
- BN_sub_word(&Ri,1);
-#else
- BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */
-#endif
- }
- else
- {
- /* This is not common..., 1 in BN_MASK2,
- * It happens when buf[0] was == 1. So for 8 bit,
- * this is 1/256, 16bit, 1 in 2^16 etc.
- */
- BN_set_word(&Ri,BN_MASK2);
- }
- BN_div(&Ri,NULL,&Ri,&tmod,ctx);
- mont->n0=Ri.d[0];
- BN_free(&Ri);
- /* mod->top=z; */
- }
-#ifdef BN_RECURSION_MONT
- else
- {
- mont->use_word=0;
- mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
-#if 1
- BN_zero(R);
- BN_set_bit(R,mont->ri);
-#else
- BN_lshift(R,BN_value_one(),mont->ri); /* R */
-#endif
- if ((BN_mod_inverse(&Ri,R,mod,ctx)) == NULL)
- goto err;
- BN_lshift(&Ri,&Ri,mont->ri); /* R*Ri */
-#if 1
- BN_sub_word(&Ri,1);
-#else
- BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */
-#endif
- BN_div(&(mont->Ni),NULL,&Ri,mod,ctx);
- BN_free(&Ri);
- }
+{
+ if (mont == NULL)
+ return;
+
+ 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;
+
+ 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;
+
+#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;
+ }
#endif
- /* setup RR for conversions */
-#if 1
- BN_zero(&(mont->RR));
- BN_set_bit(&(mont->RR),mont->ri*2);
-#else
- BN_lshift(mont->RR,BN_value_one(),mont->ri*2);
-#endif
- BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx);
+ /* 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;
- return(1);
-err:
- return(0);
- }
+ 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);
-
- BN_copy(&(to->RR),&(from->RR));
- BN_copy(&(to->N),&(from->N));
- BN_copy(&(to->Ni),&(from->Ni));
- to->use_word=from->use_word;
- to->ri=from->ri;
- to->n0=from->n0;
- return(to);
- }
-
+{
+ 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;
+}
projects / openssl.git / blobdiff