[thirdparty/openssl.git] / crypto / dh / dh_key.c

/* crypto/dh/dh_key.c */
/* 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 <openssl/rand.h>
#include <openssl/dh.h>
#include "internal/bn_int.h"

static int generate_key(DH *dh);
static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
			const BIGNUM *a, const BIGNUM *p,
			const BIGNUM *m, BN_CTX *ctx,
			BN_MONT_CTX *m_ctx);
static int dh_init(DH *dh);
static int dh_finish(DH *dh);

int DH_generate_key(DH *dh)
	{
	return dh->meth->generate_key(dh);
	}

int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
	{
	return dh->meth->compute_key(key, pub_key, dh);
	}

int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh)
	{
	int rv, pad;
	rv = dh->meth->compute_key(key, pub_key, dh);
	if (rv <= 0)
		return rv;
	pad = BN_num_bytes(dh->p) - rv;
	if (pad > 0)
		{
		memmove(key + pad, key, rv);
		memset(key, 0, pad);
		}
	return rv + pad;
	}

static DH_METHOD dh_ossl = {
"OpenSSL DH Method",
generate_key,
compute_key,
dh_bn_mod_exp,
dh_init,
dh_finish,
DH_FLAG_FIPS_METHOD,
NULL,
NULL
};

const DH_METHOD *DH_OpenSSL(void)
{
	return &dh_ossl;
}

static int generate_key(DH *dh)
	{
	int ok=0;
	int generate_new_key=0;
	unsigned l;
	BN_CTX *ctx;
	BN_MONT_CTX *mont=NULL;
	BIGNUM *pub_key=NULL,*priv_key=NULL;

	ctx = BN_CTX_new();
	if (ctx == NULL) goto err;

	if (dh->priv_key == NULL)
		{
		priv_key=BN_new();
		if (priv_key == NULL) goto err;
		generate_new_key=1;
		}
	else
		priv_key=dh->priv_key;

	if (dh->pub_key == NULL)
		{
		pub_key=BN_new();
		if (pub_key == NULL) goto err;
		}
	else
		pub_key=dh->pub_key;


	if (dh->flags & DH_FLAG_CACHE_MONT_P)
		{
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
				CRYPTO_LOCK_DH, dh->p, ctx);
		if (!mont)
			goto err;
		}

	if (generate_new_key)
		{
		if (dh->q)
			{
			do
				{
				if (!BN_rand_range(priv_key, dh->q))
					goto err;
				}
			while (BN_is_zero(priv_key) || BN_is_one(priv_key));
			}
		else
			{
			/* secret exponent length */
			l = dh->length ? dh->length : BN_num_bits(dh->p)-1;
			if (!BN_rand(priv_key, l, 0, 0)) goto err;
			}
		}

	{
		BIGNUM *local_prk = NULL;
		BIGNUM *prk;

		if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
			{
			local_prk = prk = BN_new();
			BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
			}
		else
			prk = priv_key;

		if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont))
			{
			if(local_prk) BN_free(local_prk);
			goto err;
			}
		if(local_prk) BN_free(local_prk);
	}
		
	dh->pub_key=pub_key;
	dh->priv_key=priv_key;
	ok=1;
err:
	if (ok != 1)
		DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB);

	if ((pub_key != NULL)  && (dh->pub_key == NULL))  BN_free(pub_key);
	if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
	BN_CTX_free(ctx);
	return(ok);
	}

static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
	{
	BN_CTX *ctx=NULL;
	BN_MONT_CTX *mont=NULL;
	BIGNUM *tmp;
	int ret= -1;
        int check_result;

	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
		{
		DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE);
		goto err;
		}

	ctx = BN_CTX_new();
	if (ctx == NULL) goto err;
	BN_CTX_start(ctx);
	tmp = BN_CTX_get(ctx);
	
	if (dh->priv_key == NULL)
		{
		DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
		goto err;
		}

	if (dh->flags & DH_FLAG_CACHE_MONT_P)
		{
		mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
				CRYPTO_LOCK_DH, dh->p, ctx);
		if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
			{
			/* XXX */
			BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
			}
		if (!mont)
			goto err;
		}

        if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result)
		{
		DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY);
		goto err;
		}

	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
		{
		DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB);
		goto err;
		}

	ret=BN_bn2bin(tmp,key);
err:
	if (ctx != NULL)
		{
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
		}
	return(ret);
	}

static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
			const BIGNUM *a, const BIGNUM *p,
			const BIGNUM *m, BN_CTX *ctx,
			BN_MONT_CTX *m_ctx)
	{
	/* If a is only one word long and constant time is false, use the faster
	 * exponenentiation function.
	 */
	if (bn_get_top(a) == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0))
		{
		BN_ULONG A = bn_get_words(a)[0];
		return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
		}
	else
		return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
	}


static int dh_init(DH *dh)
	{
	dh->flags |= DH_FLAG_CACHE_MONT_P;
	return(1);
	}

static int dh_finish(DH *dh)
	{
	if(dh->method_mont_p)
		BN_MONT_CTX_free(dh->method_mont_p);
	return(1);
	}
Commit	Line	Data
d02b48c6	1	/* crypto/dh/dh_key.c */
58964a49	2	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
d02b48c6 RE	3	* All rights reserved.
	4	*
	5	* This package is an SSL implementation written
	6	* by Eric Young (eay@cryptsoft.com).
	7	* The implementation was written so as to conform with Netscapes SSL.
	8	*
	9	* This library is free for commercial and non-commercial use as long as
	10	* the following conditions are aheared to. The following conditions
	11	* apply to all code found in this distribution, be it the RC4, RSA,
	12	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
	13	* included with this distribution is covered by the same copyright terms
	14	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
	15	*
	16	* Copyright remains Eric Young's, and as such any Copyright notices in
	17	* the code are not to be removed.
	18	* If this package is used in a product, Eric Young should be given attribution
	19	* as the author of the parts of the library used.
	20	* This can be in the form of a textual message at program startup or
	21	* in documentation (online or textual) provided with the package.
	22	*
	23	* Redistribution and use in source and binary forms, with or without
	24	* modification, are permitted provided that the following conditions
	25	* are met:
	26	* 1. Redistributions of source code must retain the copyright
	27	* notice, this list of conditions and the following disclaimer.
	28	* 2. Redistributions in binary form must reproduce the above copyright
	29	* notice, this list of conditions and the following disclaimer in the
	30	* documentation and/or other materials provided with the distribution.
	31	* 3. All advertising materials mentioning features or use of this software
	32	* must display the following acknowledgement:
	33	* "This product includes cryptographic software written by
	34	* Eric Young (eay@cryptsoft.com)"
	35	* The word 'cryptographic' can be left out if the rouines from the library
	36	* being used are not cryptographic related :-).
	37	* 4. If you include any Windows specific code (or a derivative thereof) from
	38	* the apps directory (application code) you must include an acknowledgement:
	39	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
	40	*
	41	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
	42	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	44	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	45	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	46	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	47	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	48	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	49	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	50	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	51	* SUCH DAMAGE.
	52	*
	53	* The licence and distribution terms for any publically available version or
	54	* derivative of this code cannot be changed. i.e. this code cannot simply be
	55	* copied and put under another distribution licence
	56	* [including the GNU Public Licence.]
	57	*/
	58
73e45b2d	59
14ae26f2	60
d02b48c6 RE	61	#include <stdio.h>
d02b48c6 RE	62	#include "cryptlib.h"
ec577822 BM	63	#include <openssl/rand.h>
ec577822 BM	64	#include <openssl/dh.h>
829ccf6a	65	#include "internal/bn_int.h"
d02b48c6	66
13066cee	67	static int generate_key(DH *dh);
f971ccb2 RL	68	static int compute_key(unsigned char key, const BIGNUM pub_key, DH *dh);
	69	static int dh_bn_mod_exp(const DH dh, BIGNUM r,
	70	const BIGNUM a, const BIGNUM p,
13066cee DSH	71	const BIGNUM m, BN_CTX ctx,
	72	BN_MONT_CTX *m_ctx);
	73	static int dh_init(DH *dh);
	74	static int dh_finish(DH *dh);
	75
6b691a5c	76	int DH_generate_key(DH *dh)
13066cee	77	{
cb78486d	78	return dh->meth->generate_key(dh);
13066cee DSH	79	}
13066cee DSH	80
f971ccb2	81	int DH_compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
13066cee	82	{
cb78486d	83	return dh->meth->compute_key(key, pub_key, dh);
13066cee DSH	84	}
13066cee DSH	85
bc91494e DSH	86	int DH_compute_key_padded(unsigned char key, const BIGNUM pub_key, DH *dh)
	87	{
	88	int rv, pad;
	89	rv = dh->meth->compute_key(key, pub_key, dh);
	90	if (rv <= 0)
	91	return rv;
	92	pad = BN_num_bytes(dh->p) - rv;
	93	if (pad > 0)
	94	{
	95	memmove(key + pad, key, rv);
	96	memset(key, 0, pad);
	97	}
	98	return rv + pad;
	99	}
	100
13066cee DSH	101	static DH_METHOD dh_ossl = {
	102	"OpenSSL DH Method",
	103	generate_key,
	104	compute_key,
	105	dh_bn_mod_exp,
	106	dh_init,
	107	dh_finish,
4960411e	108	DH_FLAG_FIPS_METHOD,
0e4aa0d2	109	NULL,
13066cee DSH	110	NULL
	111	};
	112
f971ccb2	113	const DH_METHOD *DH_OpenSSL(void)
13066cee DSH	114	{
	115	return &dh_ossl;
	116	}
	117
	118	static int generate_key(DH *dh)
d02b48c6 RE	119	{
d02b48c6 RE	120	int ok=0;
924875e5	121	int generate_new_key=0;
6aecef81	122	unsigned l;
c62b26fd	123	BN_CTX *ctx;
3cc54008	124	BN_MONT_CTX *mont=NULL;
d02b48c6 RE	125	BIGNUM pub_key=NULL,priv_key=NULL;
d02b48c6 RE	126
c62b26fd BM	127	ctx = BN_CTX_new();
c62b26fd BM	128	if (ctx == NULL) goto err;
d02b48c6 RE	129
	130	if (dh->priv_key == NULL)
	131	{
d02b48c6 RE	132	priv_key=BN_new();
d02b48c6 RE	133	if (priv_key == NULL) goto err;
924875e5	134	generate_new_key=1;
d02b48c6 RE	135	}
	136	else
	137	priv_key=dh->priv_key;
	138
	139	if (dh->pub_key == NULL)
	140	{
	141	pub_key=BN_new();
	142	if (pub_key == NULL) goto err;
	143	}
	144	else
	145	pub_key=dh->pub_key;
	146
6ec8e63a DSH	147
6ec8e63a DSH	148	if (dh->flags & DH_FLAG_CACHE_MONT_P)
dfeab068	149	{
879b1980	150	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
6ec8e63a DSH	151	CRYPTO_LOCK_DH, dh->p, ctx);
	152	if (!mont)
	153	goto err;
dfeab068	154	}
dfeab068	155
924875e5 BM	156	if (generate_new_key)
924875e5 BM	157	{
31360957 DSH	158	if (dh->q)
	159	{
	160	do
	161	{
	162	if (!BN_rand_range(priv_key, dh->q))
	163	goto err;
	164	}
	165	while (BN_is_zero(priv_key) \|\| BN_is_one(priv_key));
	166	}
	167	else
	168	{
	169	/* secret exponent length */
	170	l = dh->length ? dh->length : BN_num_bits(dh->p)-1;
	171	if (!BN_rand(priv_key, l, 0, 0)) goto err;
	172	}
924875e5	173	}
46a64376 BM	174
46a64376 BM	175	{
829ccf6a	176	BIGNUM *local_prk = NULL;
46a64376 BM	177	BIGNUM *prk;
	178
	179	if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
	180	{
829ccf6a	181	local_prk = prk = BN_new();
bd31fb21	182	BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
46a64376 BM	183	}
	184	else
	185	prk = priv_key;
	186
829ccf6a MC	187	if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont))
	188	{
	189	if(local_prk) BN_free(local_prk);
	190	goto err;
	191	}
	192	if(local_prk) BN_free(local_prk);
46a64376	193	}
d02b48c6 RE	194
	195	dh->pub_key=pub_key;
	196	dh->priv_key=priv_key;
	197	ok=1;
	198	err:
	199	if (ok != 1)
aa4ce731	200	DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB);
d02b48c6 RE	201
	202	if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key);
	203	if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
c62b26fd	204	BN_CTX_free(ctx);
d02b48c6 RE	205	return(ok);
	206	}
	207
f971ccb2	208	static int compute_key(unsigned char key, const BIGNUM pub_key, DH *dh)
d02b48c6	209	{
c2cccfc5	210	BN_CTX *ctx=NULL;
3cc54008	211	BN_MONT_CTX *mont=NULL;
d02b48c6 RE	212	BIGNUM *tmp;
d02b48c6 RE	213	int ret= -1;
bf3d6c0c	214	int check_result;
d02b48c6	215
5e3225cc BM	216	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
	217	{
	218	DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE);
	219	goto err;
	220	}
	221
c62b26fd BM	222	ctx = BN_CTX_new();
	223	if (ctx == NULL) goto err;
	224	BN_CTX_start(ctx);
	225	tmp = BN_CTX_get(ctx);
d02b48c6 RE	226
	227	if (dh->priv_key == NULL)
	228	{
aa4ce731	229	DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
d02b48c6 RE	230	goto err;
d02b48c6 RE	231	}
6ec8e63a DSH	232
6ec8e63a DSH	233	if (dh->flags & DH_FLAG_CACHE_MONT_P)
dfeab068	234	{
879b1980	235	mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
6ec8e63a	236	CRYPTO_LOCK_DH, dh->p, ctx);
46a64376 BM	237	if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
	238	{
	239	/* XXX */
bd31fb21	240	BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
46a64376	241	}
6ec8e63a DSH	242	if (!mont)
6ec8e63a DSH	243	goto err;
dfeab068 RE	244	}
dfeab068 RE	245
bf3d6c0c BL	246	if (!DH_check_pub_key(dh, pub_key, &check_result) \|\| check_result)
	247	{
	248	DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY);
	249	goto err;
	250	}
	251
cb78486d	252	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
d02b48c6	253	{
aa4ce731	254	DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB);
d02b48c6 RE	255	goto err;
	256	}
	257
	258	ret=BN_bn2bin(tmp,key);
	259	err:
47d55666 NL	260	if (ctx != NULL)
	261	{
	262	BN_CTX_end(ctx);
	263	BN_CTX_free(ctx);
	264	}
d02b48c6 RE	265	return(ret);
d02b48c6 RE	266	}
13066cee	267
f971ccb2 RL	268	static int dh_bn_mod_exp(const DH dh, BIGNUM r,
f971ccb2 RL	269	const BIGNUM a, const BIGNUM p,
13066cee DSH	270	const BIGNUM m, BN_CTX ctx,
13066cee DSH	271	BN_MONT_CTX *m_ctx)
6dad7bd6	272	{
46a64376 BM	273	/* If a is only one word long and constant time is false, use the faster
	274	* exponenentiation function.
	275	*/
829ccf6a	276	if (bn_get_top(a) == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0))
6dad7bd6	277	{
829ccf6a	278	BN_ULONG A = bn_get_words(a)[0];
6dad7bd6 BM	279	return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
	280	}
	281	else
	282	return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
	283	}
	284
13066cee DSH	285
13066cee DSH	286	static int dh_init(DH *dh)
6dad7bd6	287	{
13066cee DSH	288	dh->flags \|= DH_FLAG_CACHE_MONT_P;
13066cee DSH	289	return(1);
6dad7bd6	290	}
13066cee DSH	291
13066cee DSH	292	static int dh_finish(DH *dh)
6dad7bd6	293	{
13066cee	294	if(dh->method_mont_p)
879b1980	295	BN_MONT_CTX_free(dh->method_mont_p);
13066cee	296	return(1);
6dad7bd6	297	}