bn_mont.c

RMI的处理器au1200系列所用的BOOTLOAD,包括SD卡启动USB启动硬盘启动网络启动,并初始化硬件的所有参数,支持内核调试.

/* crypto/bn/bn_mont.c */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * 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 ([e-mail]).
 * 
 * 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 ([e-mail])"
 *    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 ([e-mail])"
 * 
 * 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.]
 */

/*
 * 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 "bn_lcl.h"
#include "workaround.h"

#define MONT_WORD		/* use the faster word-based algorithm */

int BN_mod_mul_montgomery(BIGNUM * r, BIGNUM * a, BIGNUM * b,
			  BN_MONT_CTX * mont, BN_CTX * ctx)
{
    BIGNUM *tmp, *tmp2;
    int ret = 0;

    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    tmp2 = BN_CTX_get(ctx);
    if (tmp == NULL || tmp2 == NULL)
	goto err;

    bn_check_top(tmp);
    bn_check_top(tmp2);

    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 */
    if (!BN_from_montgomery(r, tmp, mont, ctx))
	goto err;
    ret = 1;
  err:
    BN_CTX_end(ctx);
    return (ret);
}

int BN_from_montgomery(BIGNUM * ret, BIGNUM * a, BN_MONT_CTX * mont,
		       BN_CTX * ctx)
{
    int retn = 0;

#ifdef MONT_WORD
    BIGNUM *n, *r;
    BN_ULONG *ap, *np, *rp, n0, v, *nrp;
    int al, nl, max, i, x, ri;

    BN_CTX_start(ctx);
    if ((r = BN_CTX_get(ctx)) == NULL)
	goto err;

    if (!BN_copy(r, a))
	goto err;
    n = &(mont->N);

    ap = a->d;
    /* 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)) {
	r->top = 0;
	return (1);
    }

    max = (nl + al + 1);	/* allow for overflow (no?) XXX */
    if (bn_wexpand(r, max) == NULL)
	goto err;
    if (bn_wexpand(ret, max) == NULL)
	goto err;

    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));
#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++) {
#ifdef __TANDEM
	{
	    long long t1;
	    long long t2;
	    long long t3;
	    t1 = rp[0] * (n0 & 0177777);
	    t2 = 037777600000l;
	    t2 = n0 & t2;
	    t3 = rp[0] & 0177777;
	    t2 = (t3 * t2) & BN_MASK2;
	    t1 = t1 + t2;
	    v = bn_mul_add_words(rp, np, nl, (BN_ULONG) t1);
	}
#else
	v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
#endif
	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
    ret->neg = r->neg;
    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];
#endif
#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;
#endif				/* MONT_WORD */

    if (BN_ucmp(ret, &(mont->N)) >= 0) {
	BN_usub(ret, ret, &(mont->N));
    }
    retn = 1;
  err:
    BN_CTX_end(ctx);
    return (retn);
}

BN_MONT_CTX *BN_MONT_CTX_new(void)
{
    BN_MONT_CTX *ret;

    if ((ret = (BN_MONT_CTX *) Our_malloc(sizeof(BN_MONT_CTX))) == NULL)
	return (NULL);

    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->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)
	OPENSSL_free(mont);
}

int BN_MONT_CTX_set(BN_MONT_CTX * mont, const 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 MONT_WORD
    {
	BIGNUM tmod;
	BN_ULONG buf[2];

	mont->ri =
	    (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;
	if (!(BN_zero(R)))
	    goto err;
	if (!(BN_set_bit(R, BN_BITS2)))
	    goto err;		/* R */

	buf[0] = mod->d[0];	/* tmod = N mod word size */
	buf[1] = 0;
	tmod.d = buf;
	tmod.top = 1;
	tmod.dmax = 2;
	tmod.neg = mod->neg;
	/* Ri = R^-1 mod N */
	if ((BN_mod_inverse(&Ri, R, &tmod, ctx)) == NULL)
	    goto err;
	/* R*Ri */
	if (!(BN_lshift(&Ri, &Ri, BN_BITS2)))
	    goto err;
	if (!BN_is_zero(&Ri)) {
	    if (!BN_sub_word(&Ri, 1))
		goto err;
	} else {		/* if N mod word size == 1 */
	    /* Ri-- (mod word size) */
	    if (!BN_set_word(&Ri, BN_MASK2))
		goto err;
	}
	/* Ni = (R*Ri-1)/N, keep only least significant word: */
	if (!(BN_div(&Ri, NULL, &Ri, &tmod, ctx)))
	    goto err;
	mont->n0 = Ri.d[0];
	BN_free(&Ri);
    }
#else				/* !MONT_WORD */
    {				/* bignum version */
	mont->ri = BN_num_bits(mod);
	if (!(BN_zero(R)))
	    goto err;
	/* R = 2^ri */
	if (!(BN_set_bit(R, mont->ri)))
	    goto err;
	/* Ri = R^-1 mod N */
	if ((BN_mod_inverse(&Ri, R, mod, ctx)) == NULL)
	    goto err;
	/* R*Ri */
	if (!(BN_lshift(&Ri, &Ri, mont->ri)))
	    goto err;
	if (!(BN_sub_word(&Ri, 1)))
	    goto err;
	/* Ni = (R*Ri-1) / N */
	if (!(BN_div(&(mont->Ni), NULL, &Ri, mod, ctx)))
	    goto err;
	BN_free(&Ri);
    }
#endif

    /* setup RR for conversions */
    if (!(BN_zero(&(mont->RR))))
	goto err;
    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);
}

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 = from->n0;
    return (to);
}