/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2002 Networks Associates Technologies, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by ThinkSec AS and
 * NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * 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 AND CONTRIBUTORS ``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.
 */

#include <sys/param.h>

#include <err.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <unistd.h>

#include <security/pam_appl.h>
#include <security/openpam.h>

static pam_handle_t *pamh;
static struct pam_conv pamc = {
        openpam_ttyconv,
        NULL
};

static char     *yp_domain;
static char     *yp_host;

static void
usage(void)
{
        fprintf(stderr, "usage: passwd [-ly] [-d domain] [-h host] [user]\n");
        exit(1);
}

int
main(int argc, char *argv[])
{
        char hostname[MAXHOSTNAMELEN];
        struct passwd *pwd = NULL; /* Keep compiler happy. */
        int o, pam_err;
        uid_t uid;

        while ((o = getopt(argc, argv, "d:h:loy")) != -1)
                switch (o) {
                case 'd':
                        yp_domain = optarg;
                        break;
                case 'h':
                        yp_host = optarg;
                        break;
                case 'l':
                case 'o':
                case 'y':
                        /* compatibility */
                        break;
                default:
                        usage();
                }

        argc -= optind;
        argv += optind;

        uid = getuid();

        switch (argc) {
        case 0:
                if ((pwd = getpwuid(uid)) == NULL)
                        errx(1, "who are you?");
                break;
        case 1:
                if ((pwd = getpwnam(*argv)) == NULL)
                        errx(1, "%s: no such user", *argv);
                break;
        default:
                usage();
        }

        if (uid != 0 && uid != pwd->pw_uid)
                errx(1, "permission denied");

        /* check where the user's from */
        switch (pwd->pw_fields & _PWF_SOURCE) {
        case _PWF_FILES:
                fprintf(stderr, "Changing local password for %s\n",
                    pwd->pw_name);
                break;
        case _PWF_NIS:
                fprintf(stderr, "Changing NIS password for %s\n",
                    pwd->pw_name);
                break;
        default:
                /* XXX: Green men ought to be supported via PAM. */
                errx(1, 
          "Sorry, `passwd' can only change passwords for local or NIS users.");
        }

#define pam_check(func) do { \
        if (pam_err != PAM_SUCCESS) { \
                if (pam_err == PAM_AUTH_ERR || pam_err == PAM_PERM_DENIED || \
                    pam_err == PAM_AUTHTOK_RECOVERY_ERR) \
                        warnx("sorry"); \
                else \
                        warnx("%s(): %s", func, pam_strerror(pamh, pam_err)); \
                goto end; \
        } \
} while (0)

        /* initialize PAM */
        pam_err = pam_start("passwd", pwd->pw_name, &pamc, &pamh);
        pam_check("pam_start");

        pam_err = pam_set_item(pamh, PAM_TTY, ttyname(STDERR_FILENO));
        pam_check("pam_set_item");
        gethostname(hostname, sizeof hostname);
        pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
        pam_check("pam_set_item");
        pam_err = pam_set_item(pamh, PAM_RUSER, getlogin());
        pam_check("pam_set_item");

        /* set YP domain and host */
        pam_err = pam_set_data(pamh, "yp_domain", yp_domain, NULL);
        pam_check("pam_set_data");
        pam_err = pam_set_data(pamh, "yp_server", yp_host, NULL);
        pam_check("pam_set_data");

        /* set new password */
        pam_err = pam_chauthtok(pamh, 0);
        pam_check("pam_chauthtok");

 end:
        pam_end(pamh, pam_err);
        exit(pam_err == PAM_SUCCESS ? 0 : 1);
}