TwlIPL/build/libraries_sysmenu/acsign/ARM9/src/bn_me.c

/*---------------------------------------------------------------------------*
  Project:  TwlIPL
  File:     

  Copyright 2007 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date::            $
  $Rev$
  $Author$
 *---------------------------------------------------------------------------*/

/*
 * Copyright (C) 1998-2002 RSA Security Inc. All rights reserved.
 *
 * This work contains proprietary information of RSA Security.
 * Distribution is limited to authorized licensees of RSA
 * Security. Any unauthorized reproduction, distribution or
 * modification of this work is strictly prohibited.
 *
 */
/**
 * @file bn_me.c
 * @brief BN method functions and utilities
 */
#include "bn_lcl.h"
#include "bn_thx.h"

#if !(defined(NO_SPLIT) && defined(SPLIT_FILE))

#ifdef NO_SPLIT
#define SPLIT_BN_MOD_EXP_METH_DEFAULT
#define SPLIT_BN_MONT_CTX_USEIT
#define SPLIT_BN_ME_CTX_NAME
#define SPLIT_BN_ME_CTX_NEW
#define SPLIT_BN_ME_CTX_FREE
#define SPLIT_BN_ME_CTX_SET
#define SPLIT_BN_ME_CTX_MOD_EXP
#endif /* NO_SPLIT */

#ifndef NOPROTO
BN_ME_METH *bn_mod_exp_meth_default(int fallback);
#else
BN_ME_METH *bn_mod_exp_meth_default();
#endif

#ifdef SPLIT_BN_MOD_EXP_METH_DEFAULT

/**
 *            Returns the default mod_exp method, choose first available in the
 *            method table or a hardwired default
 *
 * @param     fallback  [In] Flag for choice of method
 * 			- 0 use the first value in the method table
 *                      - 1 use the all encompassing default method
 *
 * @pre       BN_default_init() has been run setting up library
 *
 * @post
 *
 * @internal  uses global table <i>bnme[]</i> and counter <i>me_num</i>
 *
 * @internal  only read the BN_ME_METH_INFO table no need for locking
 *
 * @relates   BN_library_init
 * @relates   BN_default_init
 * @relates   BN_ME_CTX_new
 * @relates   BN_ME_CTX_free
 *
 */
BN_ME_METH *bn_mod_exp_meth_default(int fallback)
{
    const BN_ME_METH *tmp;

#ifndef BN_LIBRARY_SMALL
    BN_ME_METH_INFO *meth_info;

    if(!fallback && ((meth_info = BN_bnme_get_info(0)) != NULL))
    {
        tmp = meth_info->meth();
    }
    else
#endif
    {
        /* set in bn.h or override bn_thx.h */
        tmp = BN_ME_METH_DEFAULT();
    }
    return((BN_ME_METH *)tmp);
}
#endif

#ifdef SPLIT_BN_MONT_CTX_USEIT

#ifndef NOPROTO
int bn_mont_ctx_useit(int argi);
#else
int bn_mont_ctx_useit();
#endif

/**
 * Montgomery method default useit function
 * 
 * @param argi [In] reserved for future use
 *
 * @return 0 success
 */
int bn_mont_ctx_useit(int argi)
	{
	return(0);
	}
#endif

#ifdef SPLIT_BN_ME_CTX_NAME
/**
 * Retrieve the BN method name string
 * 
 * @param ctx  [In] Method
 * 
 * @pre  ctx is valid and not NULL
 *
 * @return string pointer
 */
char *BN_ME_CTX_name(BN_ME_CTX *ctx)
	{
	return(ctx->meth->name);
	}
#endif

#ifdef SPLIT_BN_ME_CTX_NEW
/**
 * Allocate a new BN_ME_CTX structure and assign method
 *
 * @param meth [In]  Method to assign 
 * @param in   [Out] Result BN_ME_CTX
 * 
 * @note if meth is NULL system method default is used
 *
 * @retval pointer to BN_ME_CTX success
 * @retval NULL failure
 */
BN_ME_CTX *BN_ME_CTX_new(BN_ME_METH *meth, BN_ME_CTX **in)
	{
	int i;
	BN_ME_CTX *ret;

	if (in == NULL)
		in= &ret;

	if (meth == NULL)
		meth=bn_mod_exp_meth_default(0);
	i=meth->init_ctx(meth,in);
	if (i)
		return(NULL);
	else
		return(*in);
	}
#endif

#ifdef SPLIT_BN_ME_CTX_FREE
/**
 * Free context method
 *
 * @param mctx  [In]  Context object to be deallocated
 * 
 * @note it is the callers responsibility to set mctx to NULL after free
 * 
 * @pre mctx is not NULL and is valide BN_ME_CTX
 */
void BN_ME_CTX_free(BN_ME_CTX *mctx)
	{
	mctx->meth->free_ctx(mctx);
	}
#endif

#ifdef SPLIT_BN_ME_CTX_SET
/**
 * Set value to BN_ME_CTX by identifier
 *
 * @param mctx  [In]  Method context object
 * @param b     [In]  Big number 
 * @param cmd   [In]  Command identifier
 * @param flags [In]  Mask operation directives
 * @param ctx   [In]  BN data store
 *
 * @note cmd values:
 * @li BN_ME_SET_MOD will cause a method lookup is method not set
 *
 * @note passes control to set method in mctx 
 *
 * @return result of mctx method set operation
 */
int BN_ME_CTX_set(BN_ME_CTX *mctx, BIGNUM *b, int cmd, int flags, BN_CTX *ctx)
	{
#ifndef BN_LIBRARY_SMALL
#ifndef NOPROTO
	const BN_ME_METH *(*meth)(void);
#else
	const BN_ME_METH *(*meth)();
#endif
#endif  /* BN_LIBRARY_SMALL */

	/* If we are loading the modulus, and we do not have the
	 * no_lookup flag (without a null method)
	 */
	if ((cmd == BN_ME_SET_MOD) && 
		((mctx->meth != NULL) && !(flags & BN_ME_SET_FLG_NO_LOOKUP)))
		{
#ifndef BN_LIBRARY_SMALL
		meth=(const BN_ME_METH*(*)(void))
				BN_bnme_get(BN_num_bits(b),BN_BNME_F_BITS);
		if (meth != NULL)
			mctx->meth=meth();
		else
#endif
			mctx->meth=bn_mod_exp_meth_default(1);
		}
	return(mctx->meth->set(mctx,b,cmd,flags,ctx));
	}
#endif

#ifdef SPLIT_BN_ME_CTX_MOD_EXP
/**
 * Call method mod_exp operation
 *
 * @param mctx   [In]   Method context object
 * @param ret    [Out]  Result
 * @param a      [In]   Base value
 * @param p      [In]   Exponent
 * @param m      [In]   Modulus
 * @param ctx    [In]   Data storage
 * 
 * @pre <i>a</i> must be expandable 
 *
 * @return 0 success
 */
int BN_ME_CTX_mod_exp(BN_ME_CTX *mctx, BIGNUM *ret, BIGNUM *a, BIGNUM *p, 
        BIGNUM *m, BN_CTX *ctx)
	{
	int wtop;

	/* Before we call the method, make sure we are not doing 0^p,
	 * and p is not 0 or 1 */
	if (BN_is_zero(a))
		{ BN_zero(ret); return(0); }
	if (p != NULL)
		{
		if (BN_is_zero(p))
			{ BN_one(ret); return(0); }
		else if (BN_is_one(p))
			{ BN_copy(ret,a); return(0); }
		}

	/* wtop is the size 'a' needs to be for the method */
	wtop=mctx->meth->num;
	bn_zexpand(a,wtop);
	
	return(mctx->meth->mod_exp(mctx,ret,a,p,ctx));
	}
#endif

#endif