1/* crypto/dh/dh_key.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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
59#include <stdio.h>
60#include <openssl/err.h>
61#include <openssl/bn.h>
62#ifndef OPENSSL_NO_RAND
63#include <openssl/rand.h>
64#endif
65#ifndef OPENSSL_NO_DH
66#include <openssl/dh.h>
67
68#ifdef OPENSSL_FIPS
69
70static int generate_key(DH *dh);
71static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
72static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
73			const BIGNUM *a, const BIGNUM *p,
74			const BIGNUM *m, BN_CTX *ctx,
75			BN_MONT_CTX *m_ctx);
76static int dh_init(DH *dh);
77static int dh_finish(DH *dh);
78
79int DH_generate_key(DH *dh)
80	{
81	return dh->meth->generate_key(dh);
82	}
83
84int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
85	{
86	return dh->meth->compute_key(key, pub_key, dh);
87	}
88
89static DH_METHOD dh_ossl = {
90"OpenSSL DH Method",
91generate_key,
92compute_key,
93dh_bn_mod_exp,
94dh_init,
95dh_finish,
960,
97NULL
98};
99
100const DH_METHOD *DH_OpenSSL(void)
101{
102	return &dh_ossl;
103}
104
105static int generate_key(DH *dh)
106	{
107	int ok=0;
108	int generate_new_key=0;
109	unsigned l;
110	BN_CTX *ctx;
111	BN_MONT_CTX *mont;
112	BIGNUM *pub_key=NULL,*priv_key=NULL;
113
114	ctx = BN_CTX_new();
115	if (ctx == NULL) goto err;
116
117	if (dh->priv_key == NULL)
118		{
119		priv_key=BN_new();
120		if (priv_key == NULL) goto err;
121		generate_new_key=1;
122		}
123	else
124		priv_key=dh->priv_key;
125
126	if (dh->pub_key == NULL)
127		{
128		pub_key=BN_new();
129		if (pub_key == NULL) goto err;
130		}
131	else
132		pub_key=dh->pub_key;
133
134	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
135		{
136		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
137			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
138				dh->p,ctx)) goto err;
139		}
140	mont=(BN_MONT_CTX *)dh->method_mont_p;
141
142	if (generate_new_key)
143		{
144		l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
145		if (!BN_rand(priv_key, l, 0, 0)) goto err;
146		}
147	if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, priv_key,dh->p,ctx,mont))
148		goto err;
149
150	dh->pub_key=pub_key;
151	dh->priv_key=priv_key;
152	ok=1;
153err:
154	if (ok != 1)
155		DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB);
156
157	if ((pub_key != NULL)  && (dh->pub_key == NULL))  BN_free(pub_key);
158	if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
159	BN_CTX_free(ctx);
160	return(ok);
161	}
162
163static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
164	{
165	BN_CTX *ctx;
166	BN_MONT_CTX *mont;
167	BIGNUM *tmp;
168	int ret= -1;
169
170	ctx = BN_CTX_new();
171	if (ctx == NULL) goto err;
172	BN_CTX_start(ctx);
173	tmp = BN_CTX_get(ctx);
174
175	if (dh->priv_key == NULL)
176		{
177		DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
178		goto err;
179		}
180	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
181		{
182		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
183			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
184				dh->p,ctx)) goto err;
185		}
186
187	mont=(BN_MONT_CTX *)dh->method_mont_p;
188	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
189		{
190		DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
191		goto err;
192		}
193
194	ret=BN_bn2bin(tmp,key);
195err:
196	BN_CTX_end(ctx);
197	BN_CTX_free(ctx);
198	return(ret);
199	}
200
201static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
202			const BIGNUM *a, const BIGNUM *p,
203			const BIGNUM *m, BN_CTX *ctx,
204			BN_MONT_CTX *m_ctx)
205	{
206	if (a->top == 1)
207		{
208		BN_ULONG A = a->d[0];
209		return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
210		}
211	else
212		return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
213	}
214
215
216static int dh_init(DH *dh)
217	{
218	dh->flags |= DH_FLAG_CACHE_MONT_P;
219	return(1);
220	}
221
222static int dh_finish(DH *dh)
223	{
224	if(dh->method_mont_p)
225		BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p);
226	return(1);
227	}
228
229#endif
230#endif
231