/* $OpenBSD: dsaparam.c,v 1.13 2022/01/14 09:24:20 tb Exp $ */
/* 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 <openssl/opensslconf.h>        /* for OPENSSL_NO_DSA */

/* Until the key-gen callbacks are modified to use newer prototypes, we allow
 * deprecated functions for openssl-internal code */
#ifdef OPENSSL_NO_DEPRECATED
#undef OPENSSL_NO_DEPRECATED
#endif

#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "apps.h"

#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/dsa.h>
#include <openssl/pem.h>
#include <openssl/x509.h>

static struct {
        int C;
        int genkey;
        char *infile;
        int informat;
        int noout;
        char *outfile;
        int outformat;
        int text;
} dsaparam_config;

static const struct option dsaparam_options[] = {
        {
                .name = "C",
                .desc = "Convert DSA parameters into C code",
                .type = OPTION_FLAG,
                .opt.flag = &dsaparam_config.C,
        },
        {
                .name = "genkey",
                .desc = "Generate a DSA key",
                .type = OPTION_FLAG,
                .opt.flag = &dsaparam_config.genkey,
        },
        {
                .name = "in",
                .argname = "file",
                .desc = "Input file (default stdin)",
                .type = OPTION_ARG,
                .opt.arg = &dsaparam_config.infile,
        },
        {
                .name = "inform",
                .argname = "format",
                .desc = "Input format (DER or PEM (default))",
                .type = OPTION_ARG_FORMAT,
                .opt.value = &dsaparam_config.informat,
        },
        {
                .name = "noout",
                .desc = "No output",
                .type = OPTION_FLAG,
                .opt.flag = &dsaparam_config.noout,
        },
        {
                .name = "out",
                .argname = "file",
                .desc = "Output file (default stdout)",
                .type = OPTION_ARG,
                .opt.arg = &dsaparam_config.outfile,
        },
        {
                .name = "outform",
                .argname = "format",
                .desc = "Output format (DER or PEM (default))",
                .type = OPTION_ARG_FORMAT,
                .opt.value = &dsaparam_config.outformat,
        },
        {
                .name = "text",
                .desc = "Print as text",
                .type = OPTION_FLAG,
                .opt.flag = &dsaparam_config.text,
        },
        { NULL },
};

static void
dsaparam_usage(void)
{
        fprintf(stderr,
            "usage: dsaparam [-C] [-genkey] [-in file]\n"
            "    [-inform format] [-noout] [-out file] [-outform format]\n"
            "    [-text] [numbits]\n\n");
        options_usage(dsaparam_options);
}

static int dsa_cb(int p, int n, BN_GENCB *cb);

int
dsaparam_main(int argc, char **argv)
{
        DSA *dsa = NULL;
        int i;
        BIO *in = NULL, *out = NULL;
        BN_GENCB *cb = NULL;
        int ret = 1;
        int numbits = -1;
        char *strbits = NULL;

        if (single_execution) {
                if (pledge("stdio cpath wpath rpath", NULL) == -1) {
                        perror("pledge");
                        exit(1);
                }
        }

        memset(&dsaparam_config, 0, sizeof(dsaparam_config));

        dsaparam_config.informat = FORMAT_PEM;
        dsaparam_config.outformat = FORMAT_PEM;

        if (options_parse(argc, argv, dsaparam_options, &strbits, NULL) != 0) {
                dsaparam_usage();
                goto end;
        }

        if (strbits != NULL) {
                const char *errstr;
                numbits = strtonum(strbits, 0, INT_MAX, &errstr);
                if (errstr) {
                        fprintf(stderr, "Invalid number of bits: %s", errstr);
                        goto end;
                }
        }

        in = BIO_new(BIO_s_file());
        out = BIO_new(BIO_s_file());
        if (in == NULL || out == NULL) {
                ERR_print_errors(bio_err);
                goto end;
        }
        if (dsaparam_config.infile == NULL)
                BIO_set_fp(in, stdin, BIO_NOCLOSE);
        else {
                if (BIO_read_filename(in, dsaparam_config.infile) <= 0) {
                        perror(dsaparam_config.infile);
                        goto end;
                }
        }
        if (dsaparam_config.outfile == NULL) {
                BIO_set_fp(out, stdout, BIO_NOCLOSE);
        } else {
                if (BIO_write_filename(out, dsaparam_config.outfile) <= 0) {
                        perror(dsaparam_config.outfile);
                        goto end;
                }
        }

        if (numbits > 0) {
                if ((cb = BN_GENCB_new()) == NULL) {
                        BIO_printf(bio_err,
                            "Error allocating BN_GENCB object\n");
                        goto end;
                }

                BN_GENCB_set(cb, dsa_cb, bio_err);

                dsa = DSA_new();
                if (!dsa) {
                        BIO_printf(bio_err, "Error allocating DSA object\n");
                        goto end;
                }
                BIO_printf(bio_err, "Generating DSA parameters, %d bit long prime\n", numbits);
                BIO_printf(bio_err, "This could take some time\n");
                if (!DSA_generate_parameters_ex(dsa, numbits, NULL, 0, NULL, NULL, cb)) {
                        ERR_print_errors(bio_err);
                        BIO_printf(bio_err, "Error, DSA key generation failed\n");
                        goto end;
                }
        } else if (dsaparam_config.informat == FORMAT_ASN1)
                dsa = d2i_DSAparams_bio(in, NULL);
        else if (dsaparam_config.informat == FORMAT_PEM)
                dsa = PEM_read_bio_DSAparams(in, NULL, NULL, NULL);
        else {
                BIO_printf(bio_err, "bad input format specified\n");
                goto end;
        }
        if (dsa == NULL) {
                BIO_printf(bio_err, "unable to load DSA parameters\n");
                ERR_print_errors(bio_err);
                goto end;
        }
        if (dsaparam_config.text) {
                DSAparams_print(out, dsa);
        }
        if (dsaparam_config.C) {
                unsigned char *data;
                int l, len, bits_p;

                len = BN_num_bytes(DSA_get0_p(dsa));
                bits_p = BN_num_bits(DSA_get0_p(dsa));
                data = malloc(len + 20);
                if (data == NULL) {
                        perror("malloc");
                        goto end;
                }
                l = BN_bn2bin(DSA_get0_p(dsa), data);
                printf("static unsigned char dsa%d_p[] = {", bits_p);
                for (i = 0; i < l; i++) {
                        if ((i % 12) == 0)
                                printf("\n\t");
                        printf("0x%02X, ", data[i]);
                }
                printf("\n\t};\n");

                l = BN_bn2bin(DSA_get0_q(dsa), data);
                printf("static unsigned char dsa%d_q[] = {", bits_p);
                for (i = 0; i < l; i++) {
                        if ((i % 12) == 0)
                                printf("\n\t");
                        printf("0x%02X, ", data[i]);
                }
                printf("\n\t};\n");

                l = BN_bn2bin(DSA_get0_g(dsa), data);
                printf("static unsigned char dsa%d_g[] = {", bits_p);
                for (i = 0; i < l; i++) {
                        if ((i % 12) == 0)
                                printf("\n\t");
                        printf("0x%02X, ", data[i]);
                }
                free(data);
                printf("\n\t};\n\n");

                printf("DSA *get_dsa%d()\n\t{\n", bits_p);
                printf("\tBIGNUM *p = NULL, *q = NULL, *g = NULL;\n");
                printf("\tDSA *dsa;\n\n");
                printf("\tif ((dsa = DSA_new()) == NULL) return(NULL);\n");
                printf("\tp = BN_bin2bn(dsa%d_p, sizeof(dsa%d_p), NULL);\n",
                    bits_p, bits_p);
                printf("\tq = BN_bin2bn(dsa%d_q, sizeof(dsa%d_q), NULL);\n",
                    bits_p, bits_p);
                printf("\tg = BN_bin2bn(dsa%d_g, sizeof(dsa%d_g), NULL);\n",
                    bits_p, bits_p);
                printf("\tif (p == NULL || q == NULL || g == NULL)\n");
                printf("\t\t{ BN_free(p); BN_free(q); BN_free(g); DSA_free(dsa); return(NULL); }\n");
                printf("\tDSA_set0_pqg(dsa, p, q, g);\n");
                printf("\treturn(dsa);\n\t}\n");
        }
        if (!dsaparam_config.noout) {
                if (dsaparam_config.outformat == FORMAT_ASN1)
                        i = i2d_DSAparams_bio(out, dsa);
                else if (dsaparam_config.outformat == FORMAT_PEM)
                        i = PEM_write_bio_DSAparams(out, dsa);
                else {
                        BIO_printf(bio_err, "bad output format specified for outfile\n");
                        goto end;
                }
                if (!i) {
                        BIO_printf(bio_err, "unable to write DSA parameters\n");
                        ERR_print_errors(bio_err);
                        goto end;
                }
        }
        if (dsaparam_config.genkey) {
                DSA *dsakey;

                if ((dsakey = DSAparams_dup(dsa)) == NULL)
                        goto end;
                if (!DSA_generate_key(dsakey)) {
                        ERR_print_errors(bio_err);
                        DSA_free(dsakey);
                        goto end;
                }
                if (dsaparam_config.outformat == FORMAT_ASN1)
                        i = i2d_DSAPrivateKey_bio(out, dsakey);
                else if (dsaparam_config.outformat == FORMAT_PEM)
                        i = PEM_write_bio_DSAPrivateKey(out, dsakey, NULL, NULL, 0, NULL, NULL);
                else {
                        BIO_printf(bio_err, "bad output format specified for outfile\n");
                        DSA_free(dsakey);
                        goto end;
                }
                DSA_free(dsakey);
        }
        ret = 0;

 end:
        BIO_free(in);
        BIO_free_all(out);
        BN_GENCB_free(cb);
        DSA_free(dsa);

        return (ret);
}

static int
dsa_cb(int p, int n, BN_GENCB *cb)
{
        char c = '*';

        if (p == 0)
                c = '.';
        if (p == 1)
                c = '+';
        if (p == 2)
                c = '*';
        if (p == 3)
                c = '\n';
        BIO_write(BN_GENCB_get_arg(cb), &c, 1);
        (void) BIO_flush(BN_GENCB_get_arg(cb));
#ifdef GENCB_TEST
        if (stop_keygen_flag)
                return 0;
#endif
        return 1;
}