/*      $NetBSD: skey.c,v 1.18 2011/09/16 15:39:29 joerg Exp $  */

/*
 * S/KEY v1.1b (skey.c)
 *
 * Authors:
 *          Neil M. Haller <nmh@thumper.bellcore.com>
 *          Philip R. Karn <karn@chicago.qualcomm.com>
 *          John S. Walden <jsw@thumper.bellcore.com>
 *          Scott Chasin <chasin@crimelab.com>
 *
 *
 * Stand-alone program for computing responses to S/Key challenges.
 * Takes the iteration count and seed as command line args, prompts
 * for the user's key, and produces both word and hex format responses.
 *
 * Usage example:
 *      >skey 88 ka9q2
 *      Enter password:
 *      OMEN US HORN OMIT BACK AHOY
 *      >
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: skey.c,v 1.18 2011/09/16 15:39:29 joerg Exp $");
#endif

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <skey.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

__dead static void    usage(char *);

int
main(int argc, char **argv)
{
        int     n, cnt, i, pass = 0, hexmode = 0;
        char    passwd[SKEY_MAX_PW_LEN+1], key[SKEY_BINKEY_SIZE];
        char    buf[33], *seed, *slash, *t;

        cnt = 1;

        while ((i = getopt(argc, argv, "fn:p:t:x")) != -1) {
                switch (i) {
                case 'f':
                                /* this option is ignored now */
                        break;
                case 'n':
                        cnt = atoi(optarg);
                        break;
                case 'p':
                        if (strlcpy(passwd, optarg, sizeof(passwd)) >=
                                                        sizeof(passwd))
                                errx(1, "Password too long");
                        pass = 1;
                        break;
                case 't':
                        if (skey_set_algorithm(optarg) == NULL) {
                                errx(1, "Unknown hash algorithm %s", optarg);
                        }
                        break;
                case 'x':
                        hexmode = 1;
                        break;
                default:
                        usage(argv[0]);
                        break;          
                }
        }

        /* could be in the form <number>/<seed> */
        if (argc <= optind + 1) {
                /* look for / in it */
                if (argc <= optind)
                        usage(argv[0]);
                slash = strchr(argv[optind], '/');
                if (slash == NULL)
                        usage(argv[0]);
                *slash++ = '\0';
                seed = slash;

                if ((n = atoi(argv[optind])) < 0) {
                        fprintf(stderr, "%s not positive\n", argv[optind]);
                        usage(argv[0]);
                } else if (n > SKEY_MAX_SEQ) {
                        warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
                        usage(argv[0]);
                }
        } else {

                if ((n = atoi(argv[optind])) < 0) {
                        fprintf(stderr, "%s not positive\n", argv[optind]);
                        usage(argv[0]);
                } else if (n > SKEY_MAX_SEQ) {
                        warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
                        usage(argv[0]);
                }
                seed = argv[++optind];
        }

        for(t = seed; *t; t++) {
                if(!isalnum((unsigned char)*t))
                        errx(1, "seed must be alphanumeric");
        }

        if(!*seed || strlen(seed) > SKEY_MAX_SEED_LEN)
                errx(1, "seed must be between 1 and %d long", SKEY_MAX_SEED_LEN);

        /* Get user's secret password */
        if (!pass) {
                (void)fputs("Reminder - Do not use this program while "
                            "logged in via telnet or rlogin.\n", stderr);
                fprintf(stderr, "Enter secret password: ");
                readpass(passwd, sizeof(passwd));
                if (passwd[0] == '\0') 
                        exit(1);
        }

        if (strlen(passwd) < SKEY_MIN_PW_LEN)
                warnx(
        "password should be at least %d characters long according to RFC2289",
                    SKEY_MIN_PW_LEN);

        /* Crunch seed and password into starting key */
        if (keycrunch(key, seed, passwd) != 0)
                errx(1, "key crunch failed");

        if (cnt == 1) {
                while (n-- != 0)
                        f(key);
                (void)puts(hexmode ? put8(buf, key) : btoe(buf, key));
        } else {
                for (i = 0; i <= n - cnt; i++)
                        f(key);
                for (; i <= n; i++) {
                        (void)printf("%3d: %-29s", i, btoe(buf, key));
                        if (hexmode)
                                (void)printf("\t%s", put8(buf, key));
                        puts("");
                        f(key);
                }
        }
        exit(0);
}

static void
usage(char *s)
{

        fprintf(stderr,
    "usage: %s [-n count] [-p password] [-t hash] [-x] sequence# [/] key\n",
            s);
        exit(1);
}