/*      $NetBSD: lock.c,v 1.34 2016/09/05 00:40:29 sevan Exp $  */

/*
 * Copyright (c) 1980, 1987, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Bob Toxen.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)lock.c      8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: lock.c,v 1.34 2016/09/05 00:40:29 sevan Exp $");
#endif /* not lint */

/*
 * Lock a terminal up until the given key is entered, until the root
 * password is entered, or the given interval times out.
 *
 * Timeout interval is by default TIMEOUT, it can be changed with
 * an argument of the form -time where time is in minutes
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <signal.h>

#include <err.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>

#ifdef USE_PAM
#include <security/pam_appl.h>
#include <security/openpam.h>   /* for openpam_ttyconv() */
#endif

#ifdef SKEY
#include <skey.h>
#endif


#define TIMEOUT 15

static void     bye(int) __dead;
static void     hi(int);
static void     quit(int) __dead;
#ifdef SKEY
static int      skey_auth(const char *);
#endif

static struct timeval   timeout;
static struct timeval   zerotime;
static struct termios   tty, ntty;
static int      notimeout;                      /* no timeout at all */
static long     nexttime;                       /* keep the timeout time */

int
main(int argc, char **argv)
{
        struct passwd *pw;
        struct timeval timval;
        struct itimerval ntimer, otimer;
        struct tm *timp;
        time_t curtime;
        int ch, usemine;
        long sectimeout;
        char *ap, *ttynam;
        const char *tzn;
        uid_t uid = getuid();
        char hostname[MAXHOSTNAMELEN + 1], s[BUFSIZ], s1[BUFSIZ];
#ifdef USE_PAM
        pam_handle_t *pamh = NULL;
        static const struct pam_conv pamc = { &openpam_ttyconv, NULL };
        int pam_err;
#else
        char *mypw = NULL;
#endif

        if ((pw = getpwuid(getuid())) == NULL)
                errx(1, "unknown uid %lu.", (u_long)uid);

        notimeout = 0;
        sectimeout = TIMEOUT;
        usemine = 0;

        while ((ch = getopt(argc, argv, "npt:")) != -1)
                switch ((char)ch) {
                case 'n':
                        notimeout = 1;
                        break;
                case 't':
                        errno = 0;
                        if (((sectimeout = strtol(optarg, &ap, 0)) == LONG_MAX
                            || sectimeout == LONG_MIN)
                            && errno == ERANGE)
                                err(1, "illegal timeout value: %s", optarg);
                        if (optarg == ap || *ap || sectimeout <= 0)
                                errx(1, "illegal timeout value: %s", optarg);
                        if (sectimeout >= INT_MAX / 60)
                                errx(1, "too large timeout value: %ld",
                                    sectimeout);
                        break;
                case 'p':
                        usemine = 1;
#ifndef USE_PAM
                        mypw = strdup(pw->pw_passwd);
                        if (!mypw)
                                err(1, "strdup");
#endif
                        break;
                case '?':
                default:
                        (void)fprintf(stderr,
                            "usage: %s [-np] [-t timeout]\n", getprogname());
                        exit(1);
                }

#if defined(USE_PAM) || defined(SKEY)
        if (! usemine) {        /* -p with PAM or S/key needs privs */
#endif
        if (setuid(uid) == -1)  /* discard privs */
                err(1, "setuid failed");
#if defined(USE_PAM) || defined(SKEY)
        }
#endif

        timeout.tv_sec = (int)sectimeout * 60;

        if (tcgetattr(STDIN_FILENO, &tty) < 0)  /* get information for header */
                err(1, "tcgetattr failed");
        gethostname(hostname, sizeof(hostname));
        hostname[sizeof(hostname) - 1] = '\0';
        if (!(ttynam = ttyname(STDIN_FILENO)))
                err(1, "ttyname failed");
        if (gettimeofday(&timval, NULL) == -1)
                err(1, "gettimeofday failed");
        curtime = timval.tv_sec;
        nexttime = timval.tv_sec + ((int)sectimeout * 60);
        timp = localtime(&curtime);
        ap = asctime(timp);
#ifdef __SVR4
        tzn = tzname[0];
#else
        tzn = timp->tm_zone;
#endif

        if (signal(SIGINT, quit) == SIG_ERR)
                err(1, "signal failed");
        if (signal(SIGQUIT, quit) == SIG_ERR)
                err(1, "signal failed");
        ntty = tty; ntty.c_lflag &= ~ECHO;
        if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1)
                err(1, "tcsetattr");

        if (!usemine) {
                /* get key and check again */
                (void)printf("Key: ");
                if (!fgets(s, sizeof(s), stdin) || *s == '\n')
                        quit(0);
                (void)printf("\nAgain: ");
                /*
                 * Don't need EOF test here, if we get EOF, then s1 != s
                 * and the right things will happen.
                 */
                (void)fgets(s1, sizeof(s1), stdin);
                (void)putchar('\n');
                if (strcmp(s1, s)) {
                        (void)printf("\alock: passwords didn't match.\n");
                        (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
                        exit(1);
                }
                s[0] = '\0';
#ifndef USE_PAM
                mypw = s1;
#endif
        }
#ifdef USE_PAM
        if (usemine) {
                pam_err = pam_start("lock", pw->pw_name, &pamc, &pamh);
                if (pam_err != PAM_SUCCESS)
                        err(1, "pam_start: %s", pam_strerror(NULL, pam_err));
        }
#endif

        /* set signal handlers */
        if (signal(SIGINT, hi) == SIG_ERR)
                err(1, "signal failed");
        if (signal(SIGQUIT, hi) == SIG_ERR)
                err(1, "signal failed");
        if (signal(SIGTSTP, hi) == SIG_ERR)
                err(1, "signal failed");

        if (notimeout) {
                if (signal(SIGALRM, hi) == SIG_ERR)
                        err(1, "signal failed");
                (void)printf("lock: %s on %s.  no timeout.\n"
                    "time now is %.20s%s%s",
                    ttynam, hostname, ap, tzn, ap + 19);
        }
        else {
                if (signal(SIGALRM, bye) == SIG_ERR)
                        err(1, "signal failed");

                ntimer.it_interval = zerotime;
                ntimer.it_value = timeout;
                if (setitimer(ITIMER_REAL, &ntimer, &otimer) == -1)
                        err(1, "setitimer failed");

                /* header info */
                (void)printf("lock: %s on %s. timeout in %ld minutes\n"
                    "time now is %.20s%s%s",
                    ttynam, hostname, sectimeout, ap, tzn, ap + 19);
        }

        for (;;) {
#ifdef USE_PAM
                if (usemine) {
                        pam_err = pam_authenticate(pamh, 0);
                        if (pam_err == PAM_SUCCESS)
                                break;
                        goto tryagain;
                }
#endif
                (void)printf("Key: ");
                if (!fgets(s, sizeof(s), stdin)) {
                        clearerr(stdin);
                        hi(0);
                        goto tryagain;
                }
#ifndef USE_PAM
                if (usemine) {
                        s[strlen(s) - 1] = '\0';
#ifdef SKEY
                        if (strcasecmp(s, "s/key") == 0) {
                                if (skey_auth(pw->pw_name))
                                        break;
                        }
#endif
                        if (!strcmp(mypw, crypt(s, mypw)))
                                break;
                }
                else
#endif
                        if (!strcmp(s, s1))
                                break;
                (void)printf("\a\n");
 tryagain:
                if (tcsetattr(STDIN_FILENO, TCSADRAIN, &ntty) == -1
                    && errno != EINTR)
                        err(1, "tcsetattr failed");
        }
#ifdef USE_PAM
        if (usemine) {
                (void)pam_end(pamh, pam_err);
        }
#endif
        quit(0);
        /* NOTREACHED */
        return 0;
}

#ifdef SKEY
/*
 * We can't use libskey's skey_authenticate() since it
 * handles signals in a way that's inappropriate
 * for our needs. Instead we roll our own.
 */
static int
skey_auth(const char *user)
{
        char s[128];
        const char *ask;
        int ret = 0;

        if (!skey_haskey(user) && (ask = skey_keyinfo(user))) {
                (void)printf("\n[%s]\nResponse: ", ask);
                if (!fgets(s, sizeof(s), stdin) || *s == '\n')
                        clearerr(stdin);
                else {
                        s[strlen(s) - 1] = '\0';
                        if (skey_passcheck(user, s) != -1)
                                ret = 1;
                }
        } else
                (void)printf("Sorry, you have no s/key.\n");
        return ret;
}
#endif

static void
hi(int dummy)
{
        struct timeval timval;

        if (notimeout)
                (void)printf("lock: type in the unlock key.\n");
        else {
                if (gettimeofday(&timval, NULL) == -1)
                        err(1, "gettimeofday failed");
                (void)printf("lock: type in the unlock key. "
                    "timeout in %lld:%lld minutes\n",
                    (long long)(nexttime - timval.tv_sec) / 60,
                    (long long)(nexttime - timval.tv_sec) % 60);
        }
}

static void
quit(int dummy)
{
        (void)putchar('\n');
        (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
        exit(0);
}

static void
bye(int dummy)
{
        (void)tcsetattr(STDIN_FILENO, TCSADRAIN, &tty);
        (void)printf("lock: timeout\n");
        exit(1);
}