/* crypto/bn/bn_blind.c */

/* ====================================================================

 * Copyright (c) 1998-2005 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 (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.]

 */

#include <stdio.h>

#include "cryptlib.h"

#include "bn_lcl.h"

#define BN_BLINDING_COUNTER	32

struct bn_blinding_st

	{

	BIGNUM *A;

	BIGNUM *Ai;

	BIGNUM *e;

	BIGNUM *mod; /* just a reference */

	unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b;

				  * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */

	unsigned int  counter;

	unsigned long flags;

	BN_MONT_CTX *m_ctx;

	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,

			  const BIGNUM *m, BN_CTX *ctx,

			  BN_MONT_CTX *m_ctx);

	};

EXPORT_C BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)

	{

	BN_BLINDING *ret=NULL;

	bn_check_top(mod);

	if ((ret=(BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL)

		{

		BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);

		return(NULL);

		}

	memset(ret,0,sizeof(BN_BLINDING));

	if (A != NULL)

		{

		if ((ret->A  = BN_dup(A))  == NULL) goto err;

		}

	if (Ai != NULL)

		{

		if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;

		}

	ret->mod = mod;

	/* save a copy of mod in the BN_BLINDING structure */

	if ((ret->mod = BN_dup(mod)) == NULL) goto err;

	if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)

		BN_set_flags(ret->mod, BN_FLG_CONSTTIME);

	ret->counter = BN_BLINDING_COUNTER;

	return(ret);

err:

	if (ret != NULL) BN_BLINDING_free(ret);

	return(NULL);

	}

EXPORT_C void BN_BLINDING_free(BN_BLINDING *r)

	{

	if(r == NULL)

	    return;

	if (r->A  != NULL) BN_free(r->A );

	if (r->Ai != NULL) BN_free(r->Ai);

	if (r->e  != NULL) BN_free(r->e );

	if (r->mod != NULL) BN_free(r->mod); 

	OPENSSL_free(r);

	}

EXPORT_C int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)

	{

	int ret=0;

	if ((b->A == NULL) || (b->Ai == NULL))

		{

		BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);

		goto err;

		}

	if (--(b->counter) == 0 && b->e != NULL &&

		!(b->flags & BN_BLINDING_NO_RECREATE))

		{

		/* re-create blinding parameters */

		if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))

			goto err;

		}

	else if (!(b->flags & BN_BLINDING_NO_UPDATE))

		{

		if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;

		if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;

		}

	ret=1;

err:

	if (b->counter == 0)

		b->counter = BN_BLINDING_COUNTER;

	return(ret);

	}

EXPORT_C int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)

	{

	return BN_BLINDING_convert_ex(n, NULL, b, ctx);

	}

EXPORT_C int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)

	{

	int ret = 1;

	bn_check_top(n);

	if ((b->A == NULL) || (b->Ai == NULL))

		{

		BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);

		return(0);

		}

	if (r != NULL)

		{

		if (!BN_copy(r, b->Ai)) ret=0;

		}

	if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;

	return ret;

	}

EXPORT_C int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)

	{

	return BN_BLINDING_invert_ex(n, NULL, b, ctx);

	}

EXPORT_C int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)

	{

	int ret;

	bn_check_top(n);

	if ((b->A == NULL) || (b->Ai == NULL))

		{

		BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);

		return(0);

		}

	if (r != NULL)

		ret = BN_mod_mul(n, n, r, b->mod, ctx);

	else

		ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);

	if (ret >= 0)

		{

		if (!BN_BLINDING_update(b,ctx))

			return(0);

		}

	bn_check_top(n);

	return(ret);

	}

EXPORT_C unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)

	{

	return b->thread_id;

	}

EXPORT_C void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)

	{

	b->thread_id = n;

	}

EXPORT_C unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)

	{

	return b->flags;

	}

EXPORT_C void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)

	{

	b->flags = flags;

	}

EXPORT_C BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,

	const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,

	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,

			  const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),

	BN_MONT_CTX *m_ctx)

{

	int    retry_counter = 32;

	BN_BLINDING *ret = NULL;

	if (b == NULL)

		ret = BN_BLINDING_new(NULL, NULL, m);

	else

		ret = b;

	if (ret == NULL)

		goto err;

	if (ret->A  == NULL && (ret->A  = BN_new()) == NULL)

		goto err;

	if (ret->Ai == NULL && (ret->Ai	= BN_new()) == NULL)

		goto err;

	if (e != NULL)

		{

		if (ret->e != NULL)

			BN_free(ret->e);

		ret->e = BN_dup(e);

		}

	if (ret->e == NULL)

		goto err;

	if (bn_mod_exp != NULL)

		ret->bn_mod_exp = bn_mod_exp;

	if (m_ctx != NULL)

		ret->m_ctx = m_ctx;

	do {

		if (!BN_rand_range(ret->A, ret->mod)) goto err;

		if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)

			{

			/* this should almost never happen for good RSA keys */

			unsigned long error = ERR_peek_last_error();

			if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)

				{

				if (retry_counter-- == 0)

				{

					BNerr(BN_F_BN_BLINDING_CREATE_PARAM,

						BN_R_TOO_MANY_ITERATIONS);

					goto err;

				}

				ERR_clear_error();

				}

			else

				goto err;

			}

		else

			break;

	} while (1);

	if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)

		{

		if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))

			goto err;

		}

	else

		{

		if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))

			goto err;

		}

	return ret;

err:

	if (b == NULL && ret != NULL)

		{

		BN_BLINDING_free(ret);

		ret = NULL;

		}

	return ret;

}