1/* crypto/dsa/dsa_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 <time.h>
61#include "cryptlib.h"
62#ifndef OPENSSL_NO_SHA
63#include <openssl/bn.h>
64#include <openssl/dsa.h>
65#include <openssl/rand.h>
66
67#ifdef OPENSSL_FIPS
68#include <openssl/fips.h>
69#endif
70
71static int dsa_builtin_keygen(DSA *dsa);
72
73int DSA_generate_key(DSA *dsa)
74	{
75#ifdef OPENSSL_FIPS
76	if (FIPS_mode() && !(dsa->meth->flags & DSA_FLAG_FIPS_METHOD)
77			&& !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW))
78		{
79		DSAerr(DSA_F_DSA_GENERATE_KEY, DSA_R_NON_FIPS_DSA_METHOD);
80		return 0;
81		}
82#endif
83	if(dsa->meth->dsa_keygen)
84		return dsa->meth->dsa_keygen(dsa);
85#ifdef OPENSSL_FIPS
86	if (FIPS_mode())
87		return FIPS_dsa_generate_key(dsa);
88#endif
89	return dsa_builtin_keygen(dsa);
90	}
91
92static int dsa_builtin_keygen(DSA *dsa)
93	{
94	int ok=0;
95	BN_CTX *ctx=NULL;
96	BIGNUM *pub_key=NULL,*priv_key=NULL;
97
98	if ((ctx=BN_CTX_new()) == NULL) goto err;
99
100	if (dsa->priv_key == NULL)
101		{
102		if ((priv_key=BN_new()) == NULL) goto err;
103		}
104	else
105		priv_key=dsa->priv_key;
106
107	do
108		if (!BN_rand_range(priv_key,dsa->q)) goto err;
109	while (BN_is_zero(priv_key));
110
111	if (dsa->pub_key == NULL)
112		{
113		if ((pub_key=BN_new()) == NULL) goto err;
114		}
115	else
116		pub_key=dsa->pub_key;
117
118	{
119		BIGNUM local_prk;
120		BIGNUM *prk;
121
122		if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
123			{
124			BN_init(&local_prk);
125			prk = &local_prk;
126			BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
127			}
128		else
129			prk = priv_key;
130
131		if (!BN_mod_exp(pub_key,dsa->g,prk,dsa->p,ctx)) goto err;
132	}
133
134	dsa->priv_key=priv_key;
135	dsa->pub_key=pub_key;
136	ok=1;
137
138err:
139	if ((pub_key != NULL) && (dsa->pub_key == NULL)) BN_free(pub_key);
140	if ((priv_key != NULL) && (dsa->priv_key == NULL)) BN_free(priv_key);
141	if (ctx != NULL) BN_CTX_free(ctx);
142	return(ok);
143	}
144#endif
145