1/* $OpenBSD: gendh.c,v 1.14 2023/03/06 14:32:06 tb Exp $ */
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 <openssl/opensslconf.h>
60
61/* Until the key-gen callbacks are modified to use newer prototypes, we allow
62 * deprecated functions for openssl-internal code */
63#ifdef OPENSSL_NO_DEPRECATED
64#undef OPENSSL_NO_DEPRECATED
65#endif
66
67#ifndef OPENSSL_NO_DH
68
69#include <sys/types.h>
70#include <sys/stat.h>
71
72#include <limits.h>
73#include <stdio.h>
74#include <string.h>
75
76#include "apps.h"
77
78#include <openssl/bio.h>
79#include <openssl/bn.h>
80#include <openssl/dh.h>
81#include <openssl/err.h>
82#include <openssl/pem.h>
83#include <openssl/x509.h>
84
85#define DEFBITS	512
86
87static int dh_cb(int p, int n, BN_GENCB *cb);
88
89static struct {
90	int g;
91	char *outfile;
92} cfg;
93
94static const struct option gendh_options[] = {
95	{
96		.name = "2",
97		.desc = "Generate DH parameters with a generator value of 2 "
98		    "(default)",
99		.type = OPTION_VALUE,
100		.value = 2,
101		.opt.value = &cfg.g,
102	},
103	{
104		.name = "5",
105		.desc = "Generate DH parameters with a generator value of 5",
106		.type = OPTION_VALUE,
107		.value = 5,
108		.opt.value = &cfg.g,
109	},
110	{
111		.name = "out",
112		.argname = "file",
113		.desc = "Output file (default stdout)",
114		.type = OPTION_ARG,
115		.opt.arg = &cfg.outfile,
116	},
117	{ NULL },
118};
119
120static void
121gendh_usage(void)
122{
123	fprintf(stderr,
124	    "usage: gendh [-2 | -5] [-out file] [numbits]\n\n");
125	options_usage(gendh_options);
126}
127
128int
129gendh_main(int argc, char **argv)
130{
131	BN_GENCB *cb = NULL;
132	DH *dh = NULL;
133	int ret = 1, numbits = DEFBITS;
134	BIO *out = NULL;
135	char *strbits = NULL;
136
137	if (pledge("stdio cpath wpath rpath", NULL) == -1) {
138		perror("pledge");
139		exit(1);
140	}
141
142	if ((cb = BN_GENCB_new()) == NULL) {
143		BIO_printf(bio_err, "Error allocating BN_GENCB object\n");
144		goto end;
145	}
146
147	BN_GENCB_set(cb, dh_cb, bio_err);
148
149	memset(&cfg, 0, sizeof(cfg));
150
151	cfg.g = 2;
152
153	if (options_parse(argc, argv, gendh_options, &strbits, NULL) != 0) {
154		gendh_usage();
155		goto end;
156	}
157
158	if (strbits != NULL) {
159		const char *errstr;
160		numbits = strtonum(strbits, 0, INT_MAX, &errstr);
161		if (errstr) {
162			fprintf(stderr, "Invalid number of bits: %s\n", errstr);
163			goto end;
164		}
165	}
166
167	out = BIO_new(BIO_s_file());
168	if (out == NULL) {
169		ERR_print_errors(bio_err);
170		goto end;
171	}
172	if (cfg.outfile == NULL) {
173		BIO_set_fp(out, stdout, BIO_NOCLOSE);
174	} else {
175		if (BIO_write_filename(out, cfg.outfile) <= 0) {
176			perror(cfg.outfile);
177			goto end;
178		}
179	}
180
181	BIO_printf(bio_err, "Generating DH parameters, %d bit long safe prime,"
182	    " generator %d\n", numbits, cfg.g);
183	BIO_printf(bio_err, "This is going to take a long time\n");
184
185	if (((dh = DH_new()) == NULL) ||
186	    !DH_generate_parameters_ex(dh, numbits, cfg.g, cb))
187		goto end;
188
189	if (!PEM_write_bio_DHparams(out, dh))
190		goto end;
191	ret = 0;
192 end:
193	if (ret != 0)
194		ERR_print_errors(bio_err);
195	BIO_free_all(out);
196	BN_GENCB_free(cb);
197	DH_free(dh);
198
199	return (ret);
200}
201
202static int
203dh_cb(int p, int n, BN_GENCB *cb)
204{
205	char c = '*';
206
207	if (p == 0)
208		c = '.';
209	if (p == 1)
210		c = '+';
211	if (p == 2)
212		c = '*';
213	if (p == 3)
214		c = '\n';
215	BIO_write(BN_GENCB_get_arg(cb), &c, 1);
216	(void) BIO_flush(BN_GENCB_get_arg(cb));
217	return 1;
218}
219#endif
220