1/*	$NetBSD: skey.c,v 1.17 2004/11/01 21:52:07 dsl Exp $	*/
2
3/*
4 * S/KEY v1.1b (skey.c)
5 *
6 * Authors:
7 *          Neil M. Haller <nmh@thumper.bellcore.com>
8 *          Philip R. Karn <karn@chicago.qualcomm.com>
9 *          John S. Walden <jsw@thumper.bellcore.com>
10 *          Scott Chasin <chasin@crimelab.com>
11 *
12 *
13 * Stand-alone program for computing responses to S/Key challenges.
14 * Takes the iteration count and seed as command line args, prompts
15 * for the user's key, and produces both word and hex format responses.
16 *
17 * Usage example:
18 *	>skey 88 ka9q2
19 *	Enter password:
20 *	OMEN US HORN OMIT BACK AHOY
21 *	>
22 */
23
24#include <sys/cdefs.h>
25#ifndef lint
26__RCSID("$NetBSD: skey.c,v 1.17 2004/11/01 21:52:07 dsl Exp $");
27#endif
28
29#include <ctype.h>
30#include <err.h>
31#include <fcntl.h>
32#include <stdio.h>
33#include <skey.h>
34#include <stdlib.h>
35#include <string.h>
36#include <unistd.h>
37
38__dead static void    usage(char *);
39
40int
41main(int argc, char **argv)
42{
43	int     n, cnt, i, pass = 0, hexmode = 0;
44	char    passwd[SKEY_MAX_PW_LEN+1], key[SKEY_BINKEY_SIZE];
45	char	buf[33], *seed, *slash, *t;
46
47	cnt = 1;
48
49	while ((i = getopt(argc, argv, "fn:p:t:x")) != -1) {
50		switch (i) {
51		case 'f':
52				/* this option is ignored now */
53			break;
54		case 'n':
55			cnt = atoi(optarg);
56			break;
57		case 'p':
58			if (strlcpy(passwd, optarg, sizeof(passwd)) >=
59							sizeof(passwd))
60				errx(1, "Password too long");
61			pass = 1;
62			break;
63		case 't':
64			if (skey_set_algorithm(optarg) == NULL) {
65				errx(1, "Unknown hash algorithm %s", optarg);
66                        }
67			break;
68		case 'x':
69			hexmode = 1;
70			break;
71		default:
72			usage(argv[0]);
73			break;
74		}
75	}
76
77	/* could be in the form <number>/<seed> */
78	if (argc <= optind + 1) {
79		/* look for / in it */
80		if (argc <= optind)
81			usage(argv[0]);
82		slash = strchr(argv[optind], '/');
83		if (slash == NULL)
84			usage(argv[0]);
85		*slash++ = '\0';
86		seed = slash;
87
88		if ((n = atoi(argv[optind])) < 0) {
89			fprintf(stderr, "%s not positive\n", argv[optind]);
90			usage(argv[0]);
91                } else if (n > SKEY_MAX_SEQ) {
92			warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
93			usage(argv[0]);
94		}
95	} else {
96
97		if ((n = atoi(argv[optind])) < 0) {
98			fprintf(stderr, "%s not positive\n", argv[optind]);
99			usage(argv[0]);
100		} else if (n > SKEY_MAX_SEQ) {
101			warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
102			usage(argv[0]);
103		}
104		seed = argv[++optind];
105	}
106
107	for(t = seed; *t; t++) {
108		if(!isalnum((unsigned char)*t))
109			errx(1, "seed must be alphanumeric");
110	}
111
112	if(!*seed || strlen(seed) > SKEY_MAX_SEED_LEN)
113		errx(1, "seed must be between 1 and %d long", SKEY_MAX_SEED_LEN);
114
115	/* Get user's secret password */
116	if (!pass) {
117		(void)fputs("Reminder - Do not use this program while "
118			    "logged in via telnet or rlogin.\n", stderr);
119		fprintf(stderr, "Enter secret password: ");
120		readpass(passwd, sizeof(passwd));
121		if (passwd[0] == '\0')
122			exit(1);
123	}
124
125	if (strlen(passwd) < SKEY_MIN_PW_LEN)
126		warnx(
127	"password should be at least %d characters long according to RFC2289",
128		    SKEY_MIN_PW_LEN);
129
130	/* Crunch seed and password into starting key */
131	if (keycrunch(key, seed, passwd) != 0)
132		errx(1, "key crunch failed");
133
134	if (cnt == 1) {
135		while (n-- != 0)
136			f(key);
137		(void)puts(hexmode ? put8(buf, key) : btoe(buf, key));
138	} else {
139		for (i = 0; i <= n - cnt; i++)
140			f(key);
141		for (; i <= n; i++) {
142			(void)printf("%3d: %-29s", i, btoe(buf, key));
143			if (hexmode)
144				(void)printf("\t%s", put8(buf, key));
145			puts("");
146			f(key);
147		}
148	}
149	exit(0);
150}
151
152static void
153usage(char *s)
154{
155
156	fprintf(stderr,
157    "usage: %s [-n count] [-p password] [-t hash] [-x] sequence# [/] key\n",
158	    s);
159	exit(1);
160}
161