/*      $OpenBSD: lock.c,v 1.46 2019/07/24 20:23:09 schwarze Exp $      */
/*      $NetBSD: lock.c,v 1.8 1996/05/07 18:32:31 jtc 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.
 */

/*
 * Lock a terminal up until the given key or user password is entered,
 * or the given interval times out.
 */

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

#include <ctype.h>
#include <err.h>
#include <pwd.h>
#include <readpassphrase.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <limits.h>

#include <login_cap.h>
#include <bsd_auth.h>

void bye(int);
void hi(int);
void usage(void);

int     no_timeout = 0;                 /* lock terminal forever */

int
main(int argc, char *argv[])
{
        char hostname[HOST_NAME_MAX+1], s[BUFSIZ], s1[BUFSIZ], date[256];
        char hash[_PASSWORD_LEN];
        char *p, *style, *nstyle, *ttynam;
        struct itimerval ntimer, otimer;
        struct timeval timeout;
        int ch, sectimeout, usemine, cnt, tries = 10, backoff = 3;
        const char *errstr;
        struct passwd *pw;
        struct tm *timp;
        time_t curtime;
        login_cap_t *lc;

        sectimeout = 0;
        style = NULL;
        usemine = 0;
        memset(&timeout, 0, sizeof(timeout));

        if (pledge("stdio rpath wpath getpw tty proc exec", NULL) == -1)
                err(1, "pledge");

        if (!(pw = getpwuid(getuid())))
                errx(1, "unknown uid %u.", getuid());

        lc = login_getclass(pw->pw_class);
        if (lc != NULL) {
                /*
                 * We allow "login-tries" attempts to login but start
                 * slowing down after "login-backoff" attempts.
                 */
                tries = login_getcapnum(lc, "login-tries", 10, 10);
                backoff = login_getcapnum(lc, "login-backoff", 3, 3);
        }

        while ((ch = getopt(argc, argv, "a:npt:")) != -1) {
                switch (ch) {
                case 'a':
                        if (lc) {
                                style = login_getstyle(lc, optarg, "auth-lock");
                                if (style == NULL)
                                        errx(1,
                                            "invalid authentication style: %s",
                                            optarg);
                        }
                        usemine = 1;
                        break;
                case 't':
                        sectimeout = strtonum(optarg, 1, INT_MAX, &errstr);
                        if (errstr)
                                errx(1, "timeout %s: %s", errstr, optarg);
                        break;
                case 'p':
                        usemine = 1;
                        break;
                case 'n':
                        no_timeout = 1;
                        break;
                default:
                        usage();
                }
        }
        if (sectimeout == 0)
                no_timeout = 1;

        gethostname(hostname, sizeof(hostname));
        if (usemine && lc == NULL)
                errx(1, "login class not found");
        if (!(ttynam = ttyname(STDIN_FILENO)))
                errx(1, "not a terminal?");
        curtime = time(NULL);
        timp = localtime(&curtime);
        strftime(date, sizeof(date), "%c", timp);

        if (!usemine) {
                /* get key and check again */
                if (!readpassphrase("Key: ", s, sizeof(s), RPP_ECHO_OFF) ||
                    *s == '\0')
                        exit(0);
                /*
                 * Don't need EOF test here, if we get EOF, then s1 != s
                 * and the right things will happen.
                 */
                readpassphrase("Again: ", s1, sizeof(s1), RPP_ECHO_OFF);
                if (strcmp(s1, s)) {
                        warnx("\apasswords didn't match.");
                        exit(1);
                }
                crypt_newhash(s, "bcrypt", hash, sizeof(hash));
                explicit_bzero(s, sizeof(s));
                explicit_bzero(s1, sizeof(s1));
        }

        /* set signal handlers */
        signal(SIGINT, hi);
        signal(SIGQUIT, hi);
        signal(SIGTSTP, hi);
        signal(SIGALRM, bye);

        if (!no_timeout) {
                timeout.tv_sec = (time_t)sectimeout * 60;
                memset(&ntimer, 0, sizeof(ntimer));
                ntimer.it_value = timeout;
                setitimer(ITIMER_REAL, &ntimer, &otimer);
        }

        /* header info */
        if (no_timeout) {
                fprintf(stderr,
                    "%s: %s on %s. no timeout\ntime now is %s\n",
                    getprogname(), ttynam, hostname, date);
        } else {
                fprintf(stderr,
                    "%s: %s on %s. timeout in %d minutes\ntime now is %s\n",
                    getprogname(), ttynam, hostname, sectimeout, date);
        }

        for (cnt = 0;;) {
                if (!readpassphrase("Key: ", s, sizeof(s), RPP_ECHO_OFF))
                        continue;
                if (strlen(s) == 0) {
                        hi(0);
                        continue;
                }
                if (usemine) {
                        /*
                         * If user entered 's/key' or the style specified via
                         * the '-a' argument, auth_userokay() will prompt
                         * for a new password.  Otherwise, use what we have.
                         */
                        if ((strcmp(s, "s/key") == 0 &&
                            (nstyle = login_getstyle(lc, "skey", "auth-lock")))
                            || ((nstyle = style) && strcmp(s, nstyle) == 0))
                                p = NULL;
                        else
                                p = s;
                        if (auth_userokay(pw->pw_name, nstyle, "auth-lock",
                            p)) {
                                explicit_bzero(s, sizeof(s));
                                break;
                        }
                } else if (crypt_checkpass(s, hash) == 0) {
                        explicit_bzero(s, sizeof(s));
                        explicit_bzero(hash, sizeof(hash));
                        break;
                }
                putc('\a', stderr);
                cnt %= tries;
                if (++cnt > backoff) {
                        sigset_t set, oset;
                        sigfillset(&set);
                        sigprocmask(SIG_BLOCK, &set, &oset);
                        sleep((u_int)((cnt - backoff) * tries / 2));
                        sigprocmask(SIG_SETMASK, &oset, NULL);
                }
        }

        exit(0);
}

void
hi(int signo)
{
        struct itimerval left;

        dprintf(STDERR_FILENO, "%s: type in the unlock key.",
            getprogname());
        if (!no_timeout) {
                getitimer(ITIMER_REAL, &left);
                dprintf(STDERR_FILENO, " timeout in %lld:%02d minutes",
                    (long long)(left.it_value.tv_sec / 60),
                    (int)(left.it_value.tv_sec % 60));
        }
        dprintf(STDERR_FILENO, "\n");
}

void
bye(int signo)
{

        if (!no_timeout)
                warnx("timeout");
        _exit(1);
}

void
usage(void)
{
        fprintf(stderr, "usage: %s [-np] [-a style] [-t timeout]\n",
            getprogname());
        exit(1);
}