/*      $OpenBSD: check_expire.c,v 1.14 2021/10/24 21:24:20 deraadt Exp $       */

/*
 * Copyright (c) 1997 Berkeley Software Design, Inc. 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 acknowledgement:
 *      This product includes software developed by Berkeley Software Design,
 *      Inc.
 * 4. The name of Berkeley Software Design, Inc.  may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``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 BERKELEY SOFTWARE DESIGN, INC. 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.
 *
 *      BSDI $From: check_expire.c,v 2.1 1997/08/08 18:38:25 prb Exp $
 */

#include <sys/types.h>

#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <login_cap.h>
#include <bsd_auth.h>

#include "util.h"

static char *pwd_update(const struct passwd *, const struct passwd *);

#define SECSPERDAY      (24 * 60 * 60)
#define TWOWEEKS        (2 * 7 * SECSPERDAY)

int
login_check_expire(FILE *back, struct passwd *pwd, char *class, int lastchance)
{
        auth_session_t *as;
        login_cap_t *lc;
        quad_t dead, expire, warn;
        char *p;

        if ((as = auth_open()) == NULL) {
                fprintf(back, BI_VALUE
                    " errormsg Unable to create auth session\n");
                fprintf(back, BI_REJECT "\n");
                return (1);
        }
        if (auth_setpwd(as, pwd) < 0) {
                fprintf(back, BI_VALUE
                    " errormsg Unable to set pwd entry in auth session\n");
                fprintf(back, BI_REJECT "\n");
                return (1);
        }

        expire = auth_check_change(as);
        auth_close(as);

        if (expire != 0) {
                fprintf(back, BI_VALUE " expire %qd\n", expire);

                if (class == NULL)
                        class = pwd->pw_class;

                if ((lc = login_getclass(class)) == NULL) {
                        dead = 0;
                        warn = 0;
                } else {
                        dead = login_getcaptime(lc, "password-dead", 0, 0);
                        warn = login_getcaptime(lc, "password-warn",
                            TWOWEEKS, TWOWEEKS);
                        if (dead < 0)
                                dead = 0;
                        if (warn < 0)
                                warn = 0;
                }
                login_close(lc);

                /*
                 * If their password is dead (expired longer than
                 * password-dead) then just reject them.  If it is
                 * expired but not dead yet, reject them with a
                 * PWEXPIRED so login knows they can still sort of
                 * get in.
                 */
                if (expire < -dead) {
                        fprintf(back, BI_VALUE
                            " errormsg Your password has expired\n");
                        fprintf(back, BI_REJECT "\n");
                        return (1);
                }
                if (expire < 0) {
                        if (lastchance) {
                                struct passwd *npwd;

                                endpwent();

                                /*
                                 * Only let them play this game once.
                                 * Set their password change time to 1.
                                 * This will most certainly cause any
                                 * expired password to be dead, as well.
                                 */
                                npwd = pw_dup(pwd);
                                npwd->pw_change = 1;
                                p = pwd_update(npwd, pwd);
                                explicit_bzero(npwd->pw_passwd,
                                    strlen(npwd->pw_passwd));
                                free(npwd);
                                if (p != NULL) {
                                        char *errval = auth_mkvalue(p);
                                        if (errval != NULL) {
                                                fprintf(back, BI_VALUE
                                                    " errormsg %s", errval);
                                                free(errval);
                                        }
                                        fprintf(back, BI_REJECT "\n");
                                        return (1);
                                }
                        }
                        fprintf(back, BI_VALUE
                            " errormsg Your password has expired\n");
                        fprintf(back, BI_PWEXPIRED "\n");
                        return (1);
                }

                /*
                 * If their password is not expired but is about to expire
                 * then warn them.
                 */
                if (expire <= warn) {
                        fprintf(back, BI_VALUE
                            " warnmsg Your password expires on %s\n",
                            ctime(&pwd->pw_change));
                }
        }
        return (0);
}

static char *
pwd_update(const struct passwd *pwd, const struct passwd *opwd)
{
        int tfd, pfd;

        pw_init();
        tfd = pw_lock(0);
        if (tfd == -1) {
                if (errno == EEXIST)
                        return("the passwd file is busy.");
                else
                        return("can't open passwd temp file");
        }

        pfd = open(_PATH_MASTERPASSWD, O_RDONLY|O_CLOEXEC);
        if (pfd == -1) {
                pw_abort();
                return(strerror(errno));
        }

        pw_copy(pfd, tfd, pwd, opwd);
        if (pw_mkdb(pwd->pw_name, 0) == -1) {
                pw_abort();
                return("unable to update password database");
        }

        return(NULL);
}