sl@0: /* crypto/dh/dh_key.c */
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: /*
sl@0:  © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.
sl@0:  */
sl@0: 
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include "cryptlib.h"
sl@0: #include <openssl/bn.h>
sl@0: #include <openssl/rand.h>
sl@0: #include <openssl/dh.h>
sl@0: #if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))
sl@0: #include "libcrypto_wsd_macros.h"
sl@0: #include "libcrypto_wsd.h"
sl@0: #endif
sl@0: 
sl@0: 
sl@0: static int generate_key(DH *dh);
sl@0: static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
sl@0: static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
sl@0: 			const BIGNUM *a, const BIGNUM *p,
sl@0: 			const BIGNUM *m, BN_CTX *ctx,
sl@0: 			BN_MONT_CTX *m_ctx);
sl@0: static int dh_init(DH *dh);
sl@0: static int dh_finish(DH *dh);
sl@0: 
sl@0: EXPORT_C int DH_generate_key(DH *dh)
sl@0: 	{
sl@0: 	return dh->meth->generate_key(dh);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
sl@0: 	{
sl@0: 	return dh->meth->compute_key(key, pub_key, dh);
sl@0: 	}
sl@0: 
sl@0: #ifndef EMULATOR
sl@0: static DH_METHOD dh_ossl = {
sl@0: "OpenSSL DH Method",
sl@0: generate_key,
sl@0: compute_key,
sl@0: dh_bn_mod_exp,
sl@0: dh_init,
sl@0: dh_finish,
sl@0: 0,
sl@0: NULL,
sl@0: NULL
sl@0: };
sl@0: #else
sl@0: GET_STATIC_VAR_FROM_TLS(dh_ossl,dh_key,DH_METHOD)
sl@0: #define dh_ossl (*GET_WSD_VAR_NAME(dh_ossl,dh_key, s)())
sl@0: const DH_METHOD temp_s_dh_ossl = {
sl@0: "OpenSSL DH Method",
sl@0: generate_key,
sl@0: compute_key,
sl@0: dh_bn_mod_exp,
sl@0: dh_init,
sl@0: dh_finish,
sl@0: 0,
sl@0: NULL,
sl@0: NULL
sl@0: };
sl@0: 
sl@0: #endif
sl@0: EXPORT_C const DH_METHOD *DH_OpenSSL(void)
sl@0: {
sl@0: 	return &dh_ossl;
sl@0: }
sl@0: 
sl@0: static int generate_key(DH *dh)
sl@0: 	{
sl@0: 	int ok=0;
sl@0: 	int generate_new_key=0;
sl@0: 	unsigned l;
sl@0: 	BN_CTX *ctx;
sl@0: 	BN_MONT_CTX *mont=NULL;
sl@0: 	BIGNUM *pub_key=NULL,*priv_key=NULL;
sl@0: 
sl@0: 	ctx = BN_CTX_new();
sl@0: 	if (ctx == NULL) goto err;
sl@0: 
sl@0: 	if (dh->priv_key == NULL)
sl@0: 		{
sl@0: 		priv_key=BN_new();
sl@0: 		if (priv_key == NULL) goto err;
sl@0: 		generate_new_key=1;
sl@0: 		}
sl@0: 	else
sl@0: 		priv_key=dh->priv_key;
sl@0: 
sl@0: 	if (dh->pub_key == NULL)
sl@0: 		{
sl@0: 		pub_key=BN_new();
sl@0: 		if (pub_key == NULL) goto err;
sl@0: 		}
sl@0: 	else
sl@0: 		pub_key=dh->pub_key;
sl@0: 
sl@0: 
sl@0: 	if (dh->flags & DH_FLAG_CACHE_MONT_P)
sl@0: 		{
sl@0: 		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
sl@0: 				CRYPTO_LOCK_DH, dh->p, ctx);
sl@0: 		if (!mont)
sl@0: 			goto err;
sl@0: 		}
sl@0: 
sl@0: 	if (generate_new_key)
sl@0: 		{
sl@0: 		l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
sl@0: 		if (!BN_rand(priv_key, l, 0, 0)) goto err;
sl@0: 		}
sl@0: 
sl@0: 	{
sl@0: 		BIGNUM local_prk;
sl@0: 		BIGNUM *prk;
sl@0: 
sl@0: 		if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
sl@0: 			{
sl@0: 			BN_init(&local_prk);
sl@0: 			prk = &local_prk;
sl@0: 			BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
sl@0: 			}
sl@0: 		else
sl@0: 			prk = priv_key;
sl@0: 
sl@0: 		if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) goto err;
sl@0: 	}
sl@0: 		
sl@0: 	dh->pub_key=pub_key;
sl@0: 	dh->priv_key=priv_key;
sl@0: 	ok=1;
sl@0: err:
sl@0: 	if (ok != 1)
sl@0: 		DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB);
sl@0: 
sl@0: 	if ((pub_key != NULL)  && (dh->pub_key == NULL))  BN_free(pub_key);
sl@0: 	if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
sl@0: 	BN_CTX_free(ctx);
sl@0: 	return(ok);
sl@0: 	}
sl@0: 
sl@0: static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
sl@0: 	{
sl@0: 	BN_CTX *ctx=NULL;
sl@0: 	BN_MONT_CTX *mont=NULL;
sl@0: 	BIGNUM *tmp;
sl@0: 	int ret= -1;
sl@0:         int check_result;
sl@0: 	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
sl@0: 		{
sl@0: 		DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE);
sl@0: 		goto err;
sl@0: 		}
sl@0: 	ctx = BN_CTX_new();
sl@0: 	if (ctx == NULL) goto err;
sl@0: 	BN_CTX_start(ctx);
sl@0: 	tmp = BN_CTX_get(ctx);
sl@0: 	
sl@0: 	if (dh->priv_key == NULL)
sl@0: 		{
sl@0: 		DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	if (dh->flags & DH_FLAG_CACHE_MONT_P)
sl@0: 		{
sl@0: 		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
sl@0: 				CRYPTO_LOCK_DH, dh->p, ctx);
sl@0: 		if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
sl@0: 			{
sl@0: 			/* XXX */
sl@0: 			BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
sl@0: 			}
sl@0: 		if (!mont)
sl@0: 			goto err;
sl@0: 		}
sl@0: 
sl@0:         if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result)
sl@0: 		{
sl@0: 		DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
sl@0: 		{
sl@0: 		DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB);
sl@0: 		goto err;
sl@0: 		}
sl@0: 
sl@0: 	ret=BN_bn2bin(tmp,key);
sl@0: err:
sl@0: 	if (ctx != NULL)
sl@0: 		{
sl@0: 		BN_CTX_end(ctx);
sl@0: 		BN_CTX_free(ctx);
sl@0: 		}
sl@0: 	return(ret);
sl@0: 	}
sl@0: 
sl@0: static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
sl@0: 			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: 	/* If a is only one word long and constant time is false, use the faster
sl@0: 	 * exponenentiation function.
sl@0: 	 */
sl@0: 	if (a->top == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0))
sl@0: 		{
sl@0: 		BN_ULONG A = a->d[0];
sl@0: 		return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
sl@0: 		}
sl@0: 	else
sl@0: 		return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
sl@0: 	}
sl@0: 
sl@0: 
sl@0: static int dh_init(DH *dh)
sl@0: 	{
sl@0: 	dh->flags |= DH_FLAG_CACHE_MONT_P;
sl@0: 	return(1);
sl@0: 	}
sl@0: 
sl@0: static int dh_finish(DH *dh)
sl@0: 	{
sl@0: 	if(dh->method_mont_p)
sl@0: 		BN_MONT_CTX_free(dh->method_mont_p);
sl@0: 	return(1);
sl@0: 	}