/*      $NetBSD: pw_gensalt.c,v 1.15 2025/12/31 13:02:20 nia Exp $      */

/*
 * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 *
 * from OpenBSD: pwd_gensalt.c,v 1.9 1998/07/05 21:08:32 provos Exp
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: pw_gensalt.c,v 1.15 2025/12/31 13:02:20 nia Exp $");
#endif /* not lint */

#include <sys/syslimits.h>
#include <sys/types.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <err.h>
#include <grp.h>
#include <pwd.h>
#include <util.h>
#include <time.h>
#include <errno.h>

#include "crypt.h"

#ifdef HAVE_ARGON2
#include <argon2.h>
#define ARGON2_ARGON2_STR       "argon2"
#define ARGON2_ARGON2I_STR      "argon2i"
#define ARGON2_ARGON2D_STR      "argon2d"
#define ARGON2_ARGON2ID_STR     "argon2id"

crypt_private int
estimate_argon2_params(argon2_type, uint32_t *, uint32_t *, uint32_t *);
#endif /* HAVE_ARGON2 */

static const struct pw_salt {
        const char *name;
        int (*gensalt)(char *, size_t, const char *);
} salts[] = {
        { "old", __gensalt_old },
        { "new", __gensalt_new },
        { "newsalt", __gensalt_new },
        { "md5", __gensalt_md5 },
        { "sha1", __gensalt_sha1 },
        { "blowfish", __gensalt_blowfish },
#ifdef HAVE_ARGON2
        /* argon2 default to argon2id */
        { "argon2", __gensalt_argon2id},
        { "argon2id", __gensalt_argon2id},
        { "argon2i", __gensalt_argon2i},
        { "argon2d", __gensalt_argon2d},
#endif /* HAVE_ARGON2 */
        { NULL, NULL }
};

crypt_private int
/*ARGSUSED2*/
__gensalt_old(char *salt, size_t saltsiz, const char *option)
{
        if (saltsiz < 3) {
                errno = ENOSPC;
                return -1;
        }
        __crypt_to64(&salt[0], arc4random(), 2);
        salt[2] = '\0';
        return 0;
}

crypt_private int
/*ARGSUSED2*/
__gensalt_new(char *salt, size_t saltsiz, const char* option)
{
        size_t nrounds;

        if (saltsiz < 10) {
                errno = ENOSPC;
                return -1;
        }

        if (getnum(option, &nrounds) == -1)
                return -1;

        /* Check rounds, 24 bit is max */
        if (nrounds < 7250)
                nrounds = 7250;
        else if (nrounds > 0xffffff)
                nrounds = 0xffffff;
        salt[0] = _PASSWORD_EFMT1;
        __crypt_to64(&salt[1], (uint32_t)nrounds, 4);
        __crypt_to64(&salt[5], arc4random(), 4);
        salt[9] = '\0';
        return 0;
}

crypt_private int
/*ARGSUSED2*/
__gensalt_md5(char *salt, size_t saltsiz, const char *option)
{
        if (saltsiz < 13) {  /* $1$8salt$\0 */
                errno = ENOSPC;
                return -1;
        }
        salt[0] = _PASSWORD_NONDES;
        salt[1] = '1';
        salt[2] = '$';
        __crypt_to64(&salt[3], arc4random(), 4);
        __crypt_to64(&salt[7], arc4random(), 4);
        salt[11] = '$';
        salt[12] = '\0';
        return 0;
}

crypt_private int
__gensalt_sha1(char *salt, size_t saltsiz, const char *option)
{
        int n;
        size_t nrounds;

        if (getnum(option, &nrounds) == -1)
                return -1;
        n = snprintf(salt, saltsiz, "%s%u$", SHA1_MAGIC,
            __crypt_sha1_iterations(nrounds));
        /*
         * The salt can be up to 64 bytes, but 8
         * is considered enough for now.
         */
        if ((size_t)n + 9 >= saltsiz)
                return 0;
        __crypt_to64(&salt[n], arc4random(), 4);
        __crypt_to64(&salt[n + 4], arc4random(), 4);
        salt[n + 8] = '$';
        salt[n + 9] = '\0';
        return 0;
}

#ifdef HAVE_ARGON2
static int
__gensalt_argon2_decode_option(char *dst, size_t dlen,
    const char *option, argon2_type atype)
{
        char *in = 0;
        char *a = 0;
        size_t tmp = 0;
        int error = 0;
        uint32_t memory = 0;
        uint32_t time = 0;
        uint32_t threads = 0;

        memset(dst, 0, dlen);

        if (option == NULL) {
                goto done;
        }

        in = strdup(option);

        while ((a = strsep(&in, ",")) != NULL) {
                switch (*a) {
                        case 'm':
                                a += strlen("m=");
                                if ((getnum(a, &tmp)) == -1) {
                                        --error;
                                } else {
                                        memory = tmp;
                                }
                                break;
                        case 't':
                                a += strlen("t=");
                                if ((getnum(a, &tmp)) == -1) {
                                        --error;
                                } else {
                                        time = tmp;
                                }
                                break;
                        case 'p':
                                a += strlen("p=");
                                if ((getnum(a, &tmp)) == -1) {
                                        --error;
                                } else {
                                        threads = tmp;
                                }
                                break;
                        default:
                                --error;
                }
        }

        free(in);

done:
        /*
         * If parameters are unspecified, calculate some reasonable
         * ones based on system time.
         */
        if (memory < ARGON2_MIN_MEMORY ||
            time < ARGON2_MIN_TIME ||
            threads < ARGON2_MIN_THREADS) {
                estimate_argon2_params(atype, &time, &memory, &threads);
        }

        snprintf(dst, dlen, "m=%d,t=%d,p=%d", memory, time, threads);

        return error;
}


static int
__gensalt_argon2(char *salt, size_t saltsiz,
    const char *option, argon2_type atype)
{
        int rc;
        int n;
        char buf[64];

        /* get param, enforcing order and applying defaults */
        if ((rc = __gensalt_argon2_decode_option(buf,
            sizeof(buf), option, atype)) < 0) {
                return 0;
        }

        n = snprintf(salt, saltsiz, "$%s$v=%d$%s$",
                argon2_type2string(atype,0), ARGON2_VERSION_NUMBER, buf);

        if ((size_t)n + 16 >= saltsiz) {
                return 0;
        }

        __crypt_tobase64(&salt[n], arc4random(), 4);
        __crypt_tobase64(&salt[n + 4], arc4random(), 4);
        __crypt_tobase64(&salt[n + 8], arc4random(), 4);
        __crypt_tobase64(&salt[n + 12], arc4random(), 4);

        salt[n + 16] = '$';
        salt[n + 17] = '\0';

        return 0;
}

/* argon2 variant-specific hooks to generic */
crypt_private int
__gensalt_argon2id(char *salt, size_t saltsiz, const char *option)
{
        return __gensalt_argon2(salt, saltsiz, option, Argon2_id);
}

crypt_private int
__gensalt_argon2i(char *salt, size_t saltsiz, const char *option)
{
        return __gensalt_argon2(salt, saltsiz, option, Argon2_i);
}

crypt_private int
__gensalt_argon2d(char *salt, size_t saltsiz, const char *option)
{
        return __gensalt_argon2(salt, saltsiz, option, Argon2_d);
}

#endif /* HAVE_ARGON2 */


int
pw_gensalt(char *salt, size_t saltlen, const char *type, const char *option)
{
        const struct pw_salt *sp;

        for (sp = salts; sp->name; sp++)
                if (strcmp(sp->name, type) == 0)
                        return (*sp->gensalt)(salt, saltlen, option);

        errno = EINVAL;
        return -1;
}