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/* $OpenBSD: skey.c,v 1.32 2015/10/12 14:33:13 tim Exp $ */
/*
* OpenBSD S/Key (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>
* Todd C. Miller <Todd.Miller@courtesan.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 <err.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <readpassphrase.h>
#include <skey.h>
void usage();
extern char *__progname;
int
main(int argc, char *argv[])
{
int n, i, cnt = 1, pass = 0, hexmode = 0;
char passwd[SKEY_MAX_PW_LEN+1], key[SKEY_BINKEY_SIZE];
char buf[33], *seed, *slash, *algo;
const char *errstr;
if (pledge("stdio wpath tty", NULL) == -1)
err(1, "pledge");
/* If we were called as otp-METHOD, set algorithm based on that */
if (strncmp(__progname, "otp-", 4) == 0) {
algo = __progname + 4;
if (skey_set_algorithm(algo) == NULL)
errx(1, "Unknown hash algorithm %s", algo);
}
for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
if (argv[i][2] == '\0') {
/* Single character switch */
switch (argv[i][1]) {
case 'n':
if (++i == argc)
usage();
cnt = strtonum(argv[i], 1, SKEY_MAX_SEQ -1, &errstr);
if (errstr)
usage();
break;
case 'p':
if (++i == argc)
usage();
if (strlcpy(passwd, argv[i], sizeof(passwd)) >=
sizeof(passwd))
errx(1, "Password too long");
pass = 1;
break;
case 'x':
hexmode = 1;
break;
default:
usage();
}
} else {
/* Multi character switches are hash types */
if (skey_set_algorithm(&argv[i][1]) == NULL) {
warnx("Unknown hash algorithm %s", &argv[i][1]);
usage();
}
}
i++;
}
if (argc > i + 2)
usage();
/* Could be in the form <number>/<seed> */
if (argc <= i + 1) {
/* look for / in it */
if (argc <= i)
usage();
slash = strchr(argv[i], '/');
if (slash == NULL)
usage();
*slash++ = '\0';
seed = slash;
n = strtonum(argv[i], 0, SKEY_MAX_SEQ, &errstr);
if (errstr) {
warnx("%s: %s", argv[i], errstr);
usage();
}
} else {
n = strtonum(argv[i], 0, SKEY_MAX_SEQ, &errstr);
if (errstr) {
warnx("%s: %s", argv[i], errstr);
usage();
}
seed = argv[++i];
}
/* Get user's secret passphrase */
if (!pass && (readpassphrase("Enter secret passphrase: ", passwd,
sizeof(passwd), 0) == NULL || passwd[0] == '\0'))
exit(1);
/* Crunch seed and passphrase 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++) {
if (hexmode)
(void)printf("%d: %s\n", i, put8(buf, key));
else
(void)printf("%d: %-29s\n", i, btoe(buf, key));
f(key);
}
}
exit(0);
}
void
usage(void)
{
fprintf(stderr,
"usage: %s [-x] [-md5 | -rmd160 | -sha1] [-n count]\n\t"
"[-p passphrase] <sequence#>[/] key\n", __progname);
exit(1);
}
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