sl@0: /* crypto/bn/bn_blind.c */
sl@0: /* ====================================================================
sl@0:  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
sl@0:  *
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  *
sl@0:  * 1. Redistributions of source code must retain the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer. 
sl@0:  *
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in
sl@0:  *    the documentation and/or other materials provided with the
sl@0:  *    distribution.
sl@0:  *
sl@0:  * 3. All advertising materials mentioning features or use of this
sl@0:  *    software must display the following acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
sl@0:  *
sl@0:  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
sl@0:  *    endorse or promote products derived from this software without
sl@0:  *    prior written permission. For written permission, please contact
sl@0:  *    openssl-core@openssl.org.
sl@0:  *
sl@0:  * 5. Products derived from this software may not be called "OpenSSL"
sl@0:  *    nor may "OpenSSL" appear in their names without prior written
sl@0:  *    permission of the OpenSSL Project.
sl@0:  *
sl@0:  * 6. Redistributions of any form whatsoever must retain the following
sl@0:  *    acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
sl@0:  *
sl@0:  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
sl@0:  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sl@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
sl@0:  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
sl@0:  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
sl@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
sl@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
sl@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
sl@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
sl@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
sl@0:  * ====================================================================
sl@0:  *
sl@0:  * This product includes cryptographic software written by Eric Young
sl@0:  * (eay@cryptsoft.com).  This product includes software written by Tim
sl@0:  * Hudson (tjh@cryptsoft.com).
sl@0:  *
sl@0:  */
sl@0: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * This package is an SSL implementation written
sl@0:  * by Eric Young (eay@cryptsoft.com).
sl@0:  * The implementation was written so as to conform with Netscapes SSL.
sl@0:  * 
sl@0:  * This library is free for commercial and non-commercial use as long as
sl@0:  * the following conditions are aheared to.  The following conditions
sl@0:  * apply to all code found in this distribution, be it the RC4, RSA,
sl@0:  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
sl@0:  * included with this distribution is covered by the same copyright terms
sl@0:  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
sl@0:  * 
sl@0:  * Copyright remains Eric Young's, and as such any Copyright notices in
sl@0:  * the code are not to be removed.
sl@0:  * If this package is used in a product, Eric Young should be given attribution
sl@0:  * as the author of the parts of the library used.
sl@0:  * This can be in the form of a textual message at program startup or
sl@0:  * in documentation (online or textual) provided with the package.
sl@0:  * 
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  * 1. Redistributions of source code must retain the copyright
sl@0:  *    notice, this list of conditions and the following disclaimer.
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in the
sl@0:  *    documentation and/or other materials provided with the distribution.
sl@0:  * 3. All advertising materials mentioning features or use of this software
sl@0:  *    must display the following acknowledgement:
sl@0:  *    "This product includes cryptographic software written by
sl@0:  *     Eric Young (eay@cryptsoft.com)"
sl@0:  *    The word 'cryptographic' can be left out if the rouines from the library
sl@0:  *    being used are not cryptographic related :-).
sl@0:  * 4. If you include any Windows specific code (or a derivative thereof) from 
sl@0:  *    the apps directory (application code) you must include an acknowledgement:
sl@0:  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
sl@0:  * 
sl@0:  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
sl@0:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
sl@0:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
sl@0:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
sl@0:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
sl@0:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
sl@0:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
sl@0:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
sl@0:  * SUCH DAMAGE.
sl@0:  * 
sl@0:  * The licence and distribution terms for any publically available version or
sl@0:  * derivative of this code cannot be changed.  i.e. this code cannot simply be
sl@0:  * copied and put under another distribution licence
sl@0:  * [including the GNU Public Licence.]
sl@0:  */
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include "cryptlib.h"
sl@0: #include "bn_lcl.h"
sl@0: 
sl@0: #define BN_BLINDING_COUNTER	32
sl@0: 
sl@0: struct bn_blinding_st
sl@0: 	{
sl@0: 	BIGNUM *A;
sl@0: 	BIGNUM *Ai;
sl@0: 	BIGNUM *e;
sl@0: 	BIGNUM *mod; /* just a reference */
sl@0: 	unsigned long thread_id; /* added in OpenSSL 0.9.6j and 0.9.7b;
sl@0: 				  * used only by crypto/rsa/rsa_eay.c, rsa_lib.c */
sl@0: 	unsigned int  counter;
sl@0: 	unsigned long flags;
sl@0: 	BN_MONT_CTX *m_ctx;
sl@0: 	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
sl@0: 			  const BIGNUM *m, BN_CTX *ctx,
sl@0: 			  BN_MONT_CTX *m_ctx);
sl@0: 	};
sl@0: 
sl@0: EXPORT_C BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
sl@0: 	{
sl@0: 	BN_BLINDING *ret=NULL;
sl@0: 
sl@0: 	bn_check_top(mod);
sl@0: 
sl@0: 	if ((ret=(BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL)
sl@0: 		{
sl@0: 		BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);
sl@0: 		return(NULL);
sl@0: 		}
sl@0: 	memset(ret,0,sizeof(BN_BLINDING));
sl@0: 	if (A != NULL)
sl@0: 		{
sl@0: 		if ((ret->A  = BN_dup(A))  == NULL) goto err;
sl@0: 		}
sl@0: 	if (Ai != NULL)
sl@0: 		{
sl@0: 		if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;
sl@0: 		}
sl@0: 	ret->mod = mod;
sl@0: 	/* save a copy of mod in the BN_BLINDING structure */
sl@0: 	if ((ret->mod = BN_dup(mod)) == NULL) goto err;
sl@0: 	if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
sl@0: 		BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
sl@0: 	ret->counter = BN_BLINDING_COUNTER;
sl@0: 	return(ret);
sl@0: err:
sl@0: 	if (ret != NULL) BN_BLINDING_free(ret);
sl@0: 	return(NULL);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C void BN_BLINDING_free(BN_BLINDING *r)
sl@0: 	{
sl@0: 	if(r == NULL)
sl@0: 	    return;
sl@0: 
sl@0: 	if (r->A  != NULL) BN_free(r->A );
sl@0: 	if (r->Ai != NULL) BN_free(r->Ai);
sl@0: 	if (r->e  != NULL) BN_free(r->e );
sl@0: 	if (r->mod != NULL) BN_free(r->mod); 
sl@0: 	OPENSSL_free(r);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	int ret=0;
sl@0: 
sl@0: 	if ((b->A == NULL) || (b->Ai == NULL))
sl@0: 		{
sl@0: 		BNerr(BN_F_BN_BLINDING_UPDATE,BN_R_NOT_INITIALIZED);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	if (--(b->counter) == 0 && b->e != NULL &&
sl@0: 		!(b->flags & BN_BLINDING_NO_RECREATE))
sl@0: 		{
sl@0: 		/* re-create blinding parameters */
sl@0: 		if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
sl@0: 			goto err;
sl@0: 		}
sl@0: 	else if (!(b->flags & BN_BLINDING_NO_UPDATE))
sl@0: 		{
sl@0: 		if (!BN_mod_mul(b->A,b->A,b->A,b->mod,ctx)) goto err;
sl@0: 		if (!BN_mod_mul(b->Ai,b->Ai,b->Ai,b->mod,ctx)) goto err;
sl@0: 		}
sl@0: 
sl@0: 	ret=1;
sl@0: err:
sl@0: 	if (b->counter == 0)
sl@0: 		b->counter = BN_BLINDING_COUNTER;
sl@0: 	return(ret);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	return BN_BLINDING_convert_ex(n, NULL, b, ctx);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	int ret = 1;
sl@0: 
sl@0: 	bn_check_top(n);
sl@0: 
sl@0: 	if ((b->A == NULL) || (b->Ai == NULL))
sl@0: 		{
sl@0: 		BNerr(BN_F_BN_BLINDING_CONVERT_EX,BN_R_NOT_INITIALIZED);
sl@0: 		return(0);
sl@0: 		}
sl@0: 
sl@0: 	if (r != NULL)
sl@0: 		{
sl@0: 		if (!BN_copy(r, b->Ai)) ret=0;
sl@0: 		}
sl@0: 
sl@0: 	if (!BN_mod_mul(n,n,b->A,b->mod,ctx)) ret=0;
sl@0: 	
sl@0: 	return ret;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	return BN_BLINDING_invert_ex(n, NULL, b, ctx);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	int ret;
sl@0: 
sl@0: 	bn_check_top(n);
sl@0: 	if ((b->A == NULL) || (b->Ai == NULL))
sl@0: 		{
sl@0: 		BNerr(BN_F_BN_BLINDING_INVERT_EX,BN_R_NOT_INITIALIZED);
sl@0: 		return(0);
sl@0: 		}
sl@0: 
sl@0: 	if (r != NULL)
sl@0: 		ret = BN_mod_mul(n, n, r, b->mod, ctx);
sl@0: 	else
sl@0: 		ret = BN_mod_mul(n, n, b->Ai, b->mod, ctx);
sl@0: 
sl@0: 	if (ret >= 0)
sl@0: 		{
sl@0: 		if (!BN_BLINDING_update(b,ctx))
sl@0: 			return(0);
sl@0: 		}
sl@0: 	bn_check_top(n);
sl@0: 	return(ret);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C unsigned long BN_BLINDING_get_thread_id(const BN_BLINDING *b)
sl@0: 	{
sl@0: 	return b->thread_id;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C void BN_BLINDING_set_thread_id(BN_BLINDING *b, unsigned long n)
sl@0: 	{
sl@0: 	b->thread_id = n;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
sl@0: 	{
sl@0: 	return b->flags;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
sl@0: 	{
sl@0: 	b->flags = flags;
sl@0: 	}
sl@0: 
sl@0: EXPORT_C BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
sl@0: 	const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
sl@0: 	int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
sl@0: 			  const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
sl@0: 	BN_MONT_CTX *m_ctx)
sl@0: {
sl@0: 	int    retry_counter = 32;
sl@0: 	BN_BLINDING *ret = NULL;
sl@0: 
sl@0: 	if (b == NULL)
sl@0: 		ret = BN_BLINDING_new(NULL, NULL, m);
sl@0: 	else
sl@0: 		ret = b;
sl@0: 
sl@0: 	if (ret == NULL)
sl@0: 		goto err;
sl@0: 
sl@0: 	if (ret->A  == NULL && (ret->A  = BN_new()) == NULL)
sl@0: 		goto err;
sl@0: 	if (ret->Ai == NULL && (ret->Ai	= BN_new()) == NULL)
sl@0: 		goto err;
sl@0: 
sl@0: 	if (e != NULL)
sl@0: 		{
sl@0: 		if (ret->e != NULL)
sl@0: 			BN_free(ret->e);
sl@0: 		ret->e = BN_dup(e);
sl@0: 		}
sl@0: 	if (ret->e == NULL)
sl@0: 		goto err;
sl@0: 
sl@0: 	if (bn_mod_exp != NULL)
sl@0: 		ret->bn_mod_exp = bn_mod_exp;
sl@0: 	if (m_ctx != NULL)
sl@0: 		ret->m_ctx = m_ctx;
sl@0: 
sl@0: 	do {
sl@0: 		if (!BN_rand_range(ret->A, ret->mod)) goto err;
sl@0: 		if (BN_mod_inverse(ret->Ai, ret->A, ret->mod, ctx) == NULL)
sl@0: 			{
sl@0: 			/* this should almost never happen for good RSA keys */
sl@0: 			unsigned long error = ERR_peek_last_error();
sl@0: 			if (ERR_GET_REASON(error) == BN_R_NO_INVERSE)
sl@0: 				{
sl@0: 				if (retry_counter-- == 0)
sl@0: 				{
sl@0: 					BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
sl@0: 						BN_R_TOO_MANY_ITERATIONS);
sl@0: 					goto err;
sl@0: 				}
sl@0: 				ERR_clear_error();
sl@0: 				}
sl@0: 			else
sl@0: 				goto err;
sl@0: 			}
sl@0: 		else
sl@0: 			break;
sl@0: 	} while (1);
sl@0: 
sl@0: 	if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL)
sl@0: 		{
sl@0: 		if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
sl@0: 			goto err;
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
sl@0: 			goto err;
sl@0: 		}
sl@0: 
sl@0: 	return ret;
sl@0: err:
sl@0: 	if (b == NULL && ret != NULL)
sl@0: 		{
sl@0: 		BN_BLINDING_free(ret);
sl@0: 		ret = NULL;
sl@0: 		}
sl@0: 
sl@0: 	return ret;
sl@0: }