1/*
2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <openssl/opensslconf.h>
11#include <stdio.h>
12#include <string.h>
13#include <sys/types.h>
14#include <sys/stat.h>
15#include "apps.h"
16#include "progs.h"
17#include <openssl/bio.h>
18#include <openssl/err.h>
19#include <openssl/bn.h>
20#include <openssl/dsa.h>
21#include <openssl/x509.h>
22#include <openssl/pem.h>
23
24typedef enum OPTION_choice {
25    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
26    OPT_OUT, OPT_PASSOUT, OPT_ENGINE, OPT_CIPHER,
27    OPT_R_ENUM
28} OPTION_CHOICE;
29
30const OPTIONS gendsa_options[] = {
31    {OPT_HELP_STR, 1, '-', "Usage: %s [args] dsaparam-file\n"},
32    {OPT_HELP_STR, 1, '-', "Valid options are:\n"},
33    {"help", OPT_HELP, '-', "Display this summary"},
34    {"out", OPT_OUT, '>', "Output the key to the specified file"},
35    {"passout", OPT_PASSOUT, 's', "Output file pass phrase source"},
36    OPT_R_OPTIONS,
37    {"", OPT_CIPHER, '-', "Encrypt the output with any supported cipher"},
38#ifndef OPENSSL_NO_ENGINE
39    {"engine", OPT_ENGINE, 's', "Use engine, possibly a hardware device"},
40#endif
41    {NULL}
42};
43
44int gendsa_main(int argc, char **argv)
45{
46    ENGINE *e = NULL;
47    BIO *out = NULL, *in = NULL;
48    DSA *dsa = NULL;
49    const EVP_CIPHER *enc = NULL;
50    char *dsaparams = NULL;
51    char *outfile = NULL, *passoutarg = NULL, *passout = NULL, *prog;
52    OPTION_CHOICE o;
53    int ret = 1, private = 0;
54    const BIGNUM *p = NULL;
55
56    prog = opt_init(argc, argv, gendsa_options);
57    while ((o = opt_next()) != OPT_EOF) {
58        switch (o) {
59        case OPT_EOF:
60        case OPT_ERR:
61 opthelp:
62            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
63            goto end;
64        case OPT_HELP:
65            ret = 0;
66            opt_help(gendsa_options);
67            goto end;
68        case OPT_OUT:
69            outfile = opt_arg();
70            break;
71        case OPT_PASSOUT:
72            passoutarg = opt_arg();
73            break;
74        case OPT_ENGINE:
75            e = setup_engine(opt_arg(), 0);
76            break;
77        case OPT_R_CASES:
78            if (!opt_rand(o))
79                goto end;
80            break;
81        case OPT_CIPHER:
82            if (!opt_cipher(opt_unknown(), &enc))
83                goto end;
84            break;
85        }
86    }
87    argc = opt_num_rest();
88    argv = opt_rest();
89    private = 1;
90
91    if (argc != 1)
92        goto opthelp;
93    dsaparams = *argv;
94
95    if (!app_passwd(NULL, passoutarg, NULL, &passout)) {
96        BIO_printf(bio_err, "Error getting password\n");
97        goto end;
98    }
99
100    in = bio_open_default(dsaparams, 'r', FORMAT_PEM);
101    if (in == NULL)
102        goto end2;
103
104    if ((dsa = PEM_read_bio_DSAparams(in, NULL, NULL, NULL)) == NULL) {
105        BIO_printf(bio_err, "unable to load DSA parameter file\n");
106        goto end;
107    }
108    BIO_free(in);
109    in = NULL;
110
111    out = bio_open_owner(outfile, FORMAT_PEM, private);
112    if (out == NULL)
113        goto end2;
114
115    DSA_get0_pqg(dsa, &p, NULL, NULL);
116
117    if (BN_num_bits(p) > OPENSSL_DSA_MAX_MODULUS_BITS)
118        BIO_printf(bio_err,
119                   "Warning: It is not recommended to use more than %d bit for DSA keys.\n"
120                   "         Your key size is %d! Larger key size may behave not as expected.\n",
121                   OPENSSL_DSA_MAX_MODULUS_BITS, BN_num_bits(p));
122
123    BIO_printf(bio_err, "Generating DSA key, %d bits\n", BN_num_bits(p));
124    if (!DSA_generate_key(dsa))
125        goto end;
126
127    assert(private);
128    if (!PEM_write_bio_DSAPrivateKey(out, dsa, enc, NULL, 0, NULL, passout))
129        goto end;
130    ret = 0;
131 end:
132    if (ret != 0)
133        ERR_print_errors(bio_err);
134 end2:
135    BIO_free(in);
136    BIO_free_all(out);
137    DSA_free(dsa);
138    release_engine(e);
139    OPENSSL_free(passout);
140    return ret;
141}
142