/* $OpenBSD: prime.c,v 1.18 2023/07/23 11:39:29 tb Exp $ */
/* ====================================================================
 * Copyright (c) 2004 The OpenSSL Project.  All rights reserved.
 *
 * 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 above 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 acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 *
 */

#include <string.h>
#include <limits.h>

#include "apps.h"

#include <openssl/bn.h>
#include <openssl/err.h>

static struct {
        int bits;
        int checks;
        int generate;
        int hex;
        int safe;
} cfg;

static const struct option prime_options[] = {
        {
                .name = "bits",
                .argname = "n",
                .desc = "Number of bits in the generated prime number",
                .type = OPTION_ARG_INT,
                .opt.value = &cfg.bits,
        },
        {
                .name = "checks",
                .argname = "n",
                .desc = "Miller-Rabin probabilistic primality test iterations",
                .type = OPTION_ARG_INT,
                .opt.value = &cfg.checks,
        },
        {
                .name = "generate",
                .desc = "Generate a pseudo-random prime number",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.generate,
        },
        {
                .name = "hex",
                .desc = "Hexadecimal prime numbers",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.hex,
        },
        {
                .name = "safe",
                .desc = "Generate only \"safe\" prime numbers",
                .type = OPTION_FLAG,
                .opt.flag = &cfg.safe,
        },
        {NULL},
};

static void
prime_usage(void)
{
        fprintf(stderr,
            "usage: prime [-bits n] [-checks n] [-generate] [-hex] [-safe] "
            "p\n");
        options_usage(prime_options);
}

int
prime_main(int argc, char **argv)
{
        BIGNUM *bn = NULL;
        char *prime = NULL;
        BIO *bio_out;
        char *s;
        int is_prime, ret = 1;

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

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

        /* Default iterations for Miller-Rabin probabilistic primality test. */
        cfg.checks = 20;

        if (options_parse(argc, argv, prime_options, &prime, NULL) != 0) {
                prime_usage();
                return (1);
        }

        if (prime == NULL && cfg.generate == 0) {
                BIO_printf(bio_err, "No prime specified.\n");
                prime_usage();
                return (1);
        }

        if ((bio_out = BIO_new(BIO_s_file())) == NULL) {
                ERR_print_errors(bio_err);
                return (1);
        }
        BIO_set_fp(bio_out, stdout, BIO_NOCLOSE);

        if (cfg.generate != 0) {
                if (cfg.bits == 0) {
                        BIO_printf(bio_err, "Specify the number of bits.\n");
                        goto end;
                }
                bn = BN_new();
                if (!bn) {
                        BIO_printf(bio_err, "Out of memory.\n");
                        goto end;
                }
                if (!BN_generate_prime_ex(bn, cfg.bits,
                    cfg.safe, NULL, NULL, NULL)) {
                        BIO_printf(bio_err, "Prime generation error.\n");
                        goto end;
                }
                s = cfg.hex ? BN_bn2hex(bn) : BN_bn2dec(bn);
                if (s == NULL) {
                        BIO_printf(bio_err, "Out of memory.\n");
                        goto end;
                }
                BIO_printf(bio_out, "%s\n", s);
                free(s);
        } else {
                if (cfg.hex) {
                        if (!BN_hex2bn(&bn, prime)) {
                                BIO_printf(bio_err, "%s is an invalid hex "
                                    "value.\n", prime);
                                goto end;
                        }
                } else {
                        if (!BN_dec2bn(&bn, prime)) {
                                BIO_printf(bio_err, "%s is an invalid decimal "
                                    "value.\n", prime);
                                goto end;
                        }
                }

                is_prime = BN_is_prime_ex(bn, cfg.checks, NULL, NULL);
                if (is_prime < 0) {
                        BIO_printf(bio_err, "BN_is_prime_ex failed.\n");
                        goto end;
                }
                BIO_printf(bio_out, "%s is %sprime\n", prime,
                    is_prime == 1 ? "" : "not ");
        }

        ret = 0;

 end:
        BN_free(bn);
        BIO_free_all(bio_out);

        return (ret);
}