Return to skeyinit.c CVS log

Up to [local] / src / usr.bin / skeyinit

When building default seed from the hostname, only use alphanumeric
characters and make things lower case.  Also sanity check the
existing seed in skeykeys since we can't be sure it is completely
sane.  Problem noted by wozz@wookie.net

/*	$OpenBSD: skeyinit.c,v 1.25 2000/11/16 15:15:58 millert Exp $	*/
/*	$NetBSD: skeyinit.c,v 1.6 1995/06/05 19:50:48 pk Exp $	*/

/* S/KEY v1.1b (skeyinit.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>
 *
 * Modifications:
 *          Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * S/KEY initialization and seed update
 */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/time.h>
#include <sys/resource.h>

#include <err.h>
#include <errno.h>
#include <ctype.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>

#include <skey.h>

#ifndef SKEY_NAMELEN
#define SKEY_NAMELEN    4
#endif

void	usage __P((char *));

int
main(argc, argv)
	int     argc;
	char   *argv[];
{
	int     rval, nn, i, l, n=0, defaultsetup=1, zerokey=0, hexmode=0;
	time_t  now;
	char	hostname[MAXHOSTNAMELEN];
	char    passwd[SKEY_MAX_PW_LEN+2], passwd2[SKEY_MAX_PW_LEN+2];
	char	seed[SKEY_MAX_SEED_LEN+2], defaultseed[SKEY_MAX_SEED_LEN+1];
	char    tbuf[27], buf[80], key[SKEY_BINKEY_SIZE];
	char    lastc, me[UT_NAMESIZE+1], *salt, *p, *pw, *ht=NULL;
	struct skey skey;
	struct passwd *pp;
	struct tm *tm;

	if (geteuid() != 0)
		errx(1, "must be setuid root.");

	if (gethostname(hostname, sizeof(hostname)) < 0)
		err(1, "gethostname");
	for (i = 0, p = defaultseed; hostname[i] && i < SKEY_NAMELEN; i++) {
		if (isalpha(hostname[i])) {
			if (isupper(*p))
				*p++ = tolower(hostname[i]);
		} else if (isdigit(hostname[i]))
			*p++ = hostname[i];
	}
	*p = '\0';
	(void)time(&now);
	(void)sprintf(tbuf, "%05ld", (long) (now % 100000));
	(void)strncat(defaultseed, tbuf, sizeof(defaultseed) - 5);

	if ((pp = getpwuid(getuid())) == NULL)
		err(1, "no user with uid %d", getuid());
	(void)strcpy(me, pp->pw_name);

	if ((pp = getpwnam(me)) == NULL)
		err(1, "Who are you?");
	salt = pp->pw_passwd;

	for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
		if (argv[i][2] == '\0') {
			/* Single character switch */
			switch (argv[i][1]) {
			case 's':
				defaultsetup = 0;
				break;
			case 'x':
				hexmode = 1;
				break;
			case 'z':
				zerokey = 1;
				break;
			case 'n':
				if (argv[++i] == NULL || argv[i][0] == '\0')
					usage(argv[0]);
				if ((n = atoi(argv[i])) < 1 || n >= SKEY_MAX_SEQ)
					errx(1, "count must be > 0 and < %d",
					     SKEY_MAX_SEQ);
				break;
			default:
				usage(argv[0]);
			}
		} else {
			/* Multi character switches are hash types */
			if ((ht = skey_set_algorithm(&argv[i][1])) == NULL) {
				warnx("Unknown hash algorithm %s", &argv[i][1]);
				usage(argv[0]);
			}
		}
		i++;
	}

	/* check for optional user string */
	if (argc - i  > 1) {
		usage(argv[0]);
	} else if (argv[i]) {
		if ((pp = getpwnam(argv[i])) == NULL) {
			if (getuid() == 0) {
				static struct passwd _pp;

				_pp.pw_name = argv[i];
				pp = &_pp;
				warnx("Warning, user unknown: %s", argv[i]);
			} else {
				errx(1, "User unknown: %s", argv[i]);
			}
		} else if (strcmp(pp->pw_name, me) != 0) {
			if (getuid() != 0) {
				/* Only root can change other's passwds */
				errx(1, "Permission denied.");
			}
		}
	}

	if (getuid() != 0) {
		pw = getpass("Password (or `s/key'):");
		if (strcasecmp(pw, "s/key") == 0) {
			if (skey_haskey(me))
				exit(1);
			if (skey_authenticate(me))
				errx(1, "Password incorrect.");
		} else {
			p = crypt(pw, salt);
			if (strcmp(p, pp->pw_passwd))
				errx(1, "Password incorrect.");
		}
	}

	rval = skeylookup(&skey, pp->pw_name);
	switch (rval) {
		case -1:
			if (errno == ENOENT)
				errx(1, "s/key disabled");
			else
				err(1, "cannot open database");
			break;
		case 0:
			/* comment out user if asked to */
			if (zerokey)
				exit(skeyzero(&skey, pp->pw_name));

			(void)printf("[Updating %s]\n", pp->pw_name);
			(void)printf("Old key: [%s] %s\n", skey_get_algorithm(),
				     skey.seed);

			/*
			 * Sanity check old seed.
			 */
			l = strlen(skey.seed);
			for (p = skey.seed; *p; p++) {
				if (isalpha(*p)) {
					if (isupper(*p))
						*p = tolower(*p);
				} else if (!isdigit(*p)) {
					memmove(p, p + 1, l - (p - skey.seed));
					l--;
				}
			}

			/*
			 * Let's be nice if they have an skey.seed that
			 * ends in 0-8 just add one
			 */
			if (l > 0) {
				lastc = skey.seed[l - 1];
				if (isdigit(lastc) && lastc != '9') {
					(void)strcpy(defaultseed, skey.seed);
					defaultseed[l - 1] = lastc + 1;
				}
				if (isdigit(lastc) && lastc == '9' && l < 16) {
					(void)strcpy(defaultseed, skey.seed);
					defaultseed[l - 1] = '0';
					defaultseed[l] = '0';
					defaultseed[l + 1] = '\0';
				}
			}
			break;
		case 1:
			if (zerokey)
				errx(1, "You have no entry to zero.");
			(void)printf("[Adding %s]\n", pp->pw_name);
			break;
	}
	if (n == 0)
		n = 99;

	/* Set hash type if asked to */
	if (ht) {
		/* Need to zero out old key when changing algorithm */
		if (strcmp(ht, skey_get_algorithm()) && skey_set_algorithm(ht))
			zerokey = 1;
	}

	if (!defaultsetup) {
		(void)printf("You need the 6 english words generated from the \"skey\" command.\n");
		for (i = 0; ; i++) {
			if (i >= 2)
				exit(1);

			(void)printf("Enter sequence count from 1 to %d: ",
				     SKEY_MAX_SEQ);
			(void)fgets(buf, sizeof(buf), stdin);
			n = atoi(buf);
			if (n > 0 && n < SKEY_MAX_SEQ)
				break;	/* Valid range */
			(void)printf("Error: Count must be > 0 and < %d\n",
				     SKEY_MAX_SEQ);
		}

		for (i = 0;; i++) {
			if (i >= 2)
				exit(1);

			(void)printf("Enter new key [default %s]: ",
				     defaultseed);
			(void)fgets(seed, sizeof(seed), stdin);
			rip(seed);
			if (seed[0] == '\0')
				(void)strcpy(seed, defaultseed);
			for (p = seed; *p; p++) {
				if (isalpha(*p)) {
					if (isupper(*p))
						*p = tolower(*p);
				} else if (!isdigit(*p)) {
					(void)puts("Error: seed may only contain alpha numeric characters");
					break;
				}
			}
			if (*p == '\0')
				break;  /* Valid seed */
		}
		if (strlen(seed) > SKEY_MAX_SEED_LEN) {
			(void)printf("Notice: Seed truncated to %d characters.\n",
				     SKEY_MAX_SEED_LEN);
			seed[SKEY_MAX_SEED_LEN] = '\0';
		}

		for (i = 0;; i++) {
			if (i >= 2)
				exit(1);

			(void)printf("otp-%s %d %s\nS/Key access password: ",
				     skey_get_algorithm(), n, seed);
			(void)fgets(buf, sizeof(buf), stdin);
			rip(buf);
			backspace(buf);

			if (buf[0] == '?') {
				(void)puts("Enter 6 English words from secure S/Key calculation.");
				continue;
			} else if (buf[0] == '\0')
				exit(1);
			if (etob(key, buf) == 1 || atob8(key, buf) == 0)
				break;	/* Valid format */
			(void)puts("Invalid format - try again with 6 English words.");
		}
	} else {
		/* Get user's secret password */
		fputs("Reminder - Only use this method if you are directly connected\n           or have an encrypted channel.  If you are using telnet\n           or rlogin, exit with no password and use skeyinit -s.\n", stderr);

		for (i = 0;; i++) {
			if (i > 2)
				exit(1);

			(void)fputs("Enter secret password: ", stderr);
			readpass(passwd, sizeof(passwd));
			if (passwd[0] == '\0')
				exit(1);

			if (strlen(passwd) < SKEY_MIN_PW_LEN) {
				(void)fprintf(stderr,
				    "Your password must be at least %d characters long.\n", SKEY_MIN_PW_LEN);
				continue;
			} else if (strcmp(passwd, pp->pw_name) == 0) {
				(void)fputs("Your password may not be the same as your user name.\n", stderr);
				continue;
			} else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") == strlen(passwd)) {
				(void)fputs("Your password must contain more than just lower case letters.\nWhitespace, numbers, and puctuation are suggested.\n", stderr);
				continue;
			}

			(void)fputs("Again secret password: ", stderr);
			readpass(passwd2, sizeof(passwd));

			if (strcmp(passwd, passwd2) == 0)
				break;

			(void)fputs("Passwords do not match.\n", stderr);
		}

		/* Crunch seed and password into starting key */
		(void)strcpy(seed, defaultseed);
		if (keycrunch(key, seed, passwd) != 0)
			err(2, "key crunch failed");

		nn = n;
		while (nn-- != 0)
			f(key);
	}
	(void)time(&now);
	tm = localtime(&now);
	(void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm);

	if ((skey.val = (char *)malloc(16 + 1)) == NULL)
		err(1, "Can't allocate memory");

	/* Zero out old key if necesary (entry would change size) */
	if (zerokey) {
		(void)skeyzero(&skey, pp->pw_name);
		/* Re-open keys file and seek to the end */
		if (skeylookup(&skey, pp->pw_name) == -1)
			err(1, "cannot open database");
	}

	btoa8(skey.val, key);

	/*
	 * Obtain an exclusive lock on the key file so we don't
	 * clobber someone authenticating themselves at the same time.
	 */
	for (i = 0; i < 300; i++) {
		if ((rval = flock(fileno(skey.keyfile), LOCK_EX|LOCK_NB)) == 0
		    || errno != EWOULDBLOCK)
			break;
		usleep(100000);			/* Sleep for 0.1 seconds */
	}
	if (rval == -1)	{			/* Can't get exclusive lock */
		errno = EAGAIN;
		err(1, "cannot open database");
	}

	/* Don't save algorithm type for md4 (keep record length same) */
	if (strcmp(skey_get_algorithm(), "md4") == 0)
		(void)fprintf(skey.keyfile, "%s %04d %-16s %s %-21s\n",
		    pp->pw_name, n, seed, skey.val, tbuf);
	else
		(void)fprintf(skey.keyfile, "%s %s %04d %-16s %s %-21s\n",
		    pp->pw_name, skey_get_algorithm(), n, seed, skey.val, tbuf);

	(void)fclose(skey.keyfile);

	(void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name,
		     skey_get_algorithm(), n, seed);
	(void)printf("Next login password: %s\n\n",
		     hexmode ? put8(buf, key) : btoe(buf, key));
	exit(0);
}

void
usage(s)
	char *s;
{
	(void)fprintf(stderr,
		"Usage: %s [-s] [-x] [-z] [-n count] [-md4|-md5|-sha1|-rmd160] [user]\n", s);
	exit(1);
}