/* $OpenBSD: skeyinit.c,v 1.30 2001/11/01 18:26:58 miod Exp $ */
/* OpenBSD S/Key (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>
* 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 <readpassphrase.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 lockeof __P((struct skey *, char *));
void usage __P((char *));
void secure_mode __P((int *, char *, char *, char *, char *, size_t));
void normal_mode __P((char *, int, char *, char *, char *));
void timedout __P((int));
int
main(argc, argv)
int argc;
char *argv[];
{
int rval, i, l, n=0, defaultsetup=1, zerokey=0, hexmode=0;
int oldmd4=0;
time_t now;
size_t seedlen;
char hostname[MAXHOSTNAMELEN];
char passwd[SKEY_MAX_PW_LEN+2];
char seed[SKEY_MAX_SEED_LEN+2], defaultseed[SKEY_MAX_SEED_LEN+1];
char tbuf[27], buf[256], key[SKEY_BINKEY_SIZE];
char lastc, me[UT_NAMESIZE+1], *salt, *p, *ht=NULL;
struct skey skey;
struct passwd *pp;
struct tm *tm;
if (geteuid() != 0)
errx(1, "must be setuid root.");
/* Build up a default seed based on the hostname and time */
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(hostname[i]))
hostname[i] = tolower(hostname[i]);
*p++ = 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 (defaultsetup)
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, hit return now and use skeyinit -s.\n", stderr);
if (getuid() != 0) {
/* XXX - use BSD auth */
passwd[0] = '\0';
if (!defaultsetup && skeychallenge(&skey, me, buf) == 0) {
printf("Enter S/Key password below or hit return twice "
"to enter standard password.\n%s\n", buf);
fflush(stdout);
if (!readpassphrase("S/Key Password: ", passwd,
sizeof(passwd), 0) || passwd[0] == '\0') {
readpassphrase("S/Key Password: [echo on] ",
passwd, sizeof(passwd), RPP_ECHO_ON);
}
}
if (passwd[0]) {
if (skeyverify(&skey, passwd) != 0)
errx(1, "Password incorrect.");
} else {
fflush(stdout);
readpassphrase("Password: ", passwd, sizeof(passwd), 0);
if (strcmp(crypt(passwd, salt), pp->pw_passwd)) {
if (passwd[0])
warnx("Password incorrect.");
exit(1);
}
}
}
/*
* Lookup and lock the record we are about to modify.
* If this is a new entry this will prevent other users
* from appending new entries (and clobbering ours).
*/
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));
(void)printf("[Updating %s with %s]\n", pp->pw_name,
ht ? ht : skey_get_algorithm());
(void)printf("Old seed: [%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--;
}
}
/* If the seed 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 with %s]\n", pp->pw_name,
ht ? ht : skey_get_algorithm());
lockeof(&skey, pp->pw_name);
break;
}
if (n == 0)
n = 99;
/* Do we have an old-style md4 entry? */
if (rval == 0 && strcmp("md4", skey_get_algorithm()) == 0 &&
strcmp("md4", skey.logname + strlen(skey.logname) + 1) != 0)
oldmd4 = 1;
/* Set hash type if asked to */
if (ht && strcmp(ht, skey_get_algorithm()) != 0)
skey_set_algorithm(ht);
alarm(180);
if (!defaultsetup)
secure_mode(&n, key, seed, defaultseed, buf, sizeof(buf));
else
normal_mode(pp->pw_name, n, key, seed, defaultseed);
alarm(0);
(void)time(&now);
tm = localtime(&now);
(void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm);
/* If this is an exiting entry, compute the line length and seed pad */
seedlen = SKEY_MAX_SEED_LEN;
if (rval == 0) {
int nlen;
nlen = strlen(pp->pw_name) + 1 + strlen(skey_get_algorithm()) +
1 + 4 + 1 + strlen(seed) + 1 + 16 + 1 + strlen(tbuf) + 1;
/*
* If there was no hash type (md4) add one unless we
* are short on space.
*/
if (oldmd4) {
if (nlen > skey.len)
nlen -= 4;
else
oldmd4 = 0;
}
/* If new entry is longer than the old, comment out the old. */
if (nlen > skey.len) {
(void)skeyzero(&skey);
/* Re-open keys file and seek to the end */
if (skeylookup(&skey, pp->pw_name) == -1)
err(1, "cannot reopen database");
lockeof(&skey, pp->pw_name);
} else {
/* Compute how much to space-pad the seed */
seedlen = strlen(seed) + (skey.len - nlen);
}
}
if ((skey.val = (char *)malloc(16 + 1)) == NULL)
err(1, "Can't allocate memory");
btoa8(skey.val, key);
/* Don't save algorithm type for md4 (maintain record length) */
/* XXX - should check return values of fprintf + fclose */
if (oldmd4)
(void)fprintf(skey.keyfile, "%s %04d %-*s %s %-21s\n",
pp->pw_name, n, seedlen, seed, skey.val, tbuf);
else
(void)fprintf(skey.keyfile, "%s %s %04d %-*s %s %-21s\n",
pp->pw_name, skey_get_algorithm(), n, seedlen, 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
lockeof(mp, user)
struct skey *mp;
char *user;
{
struct flock fl;
fseek(mp->keyfile, 0, SEEK_END);
dolock:
fl.l_start = ftell(mp->keyfile);
fl.l_len = mp->len;
fl.l_pid = getpid();
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
if (fcntl(fileno(mp->keyfile), F_SETLKW, &fl) == -1)
err(1, "Can't lock database");
/* Make sure we are still at the end. */
fseek(mp->keyfile, 0, SEEK_END);
if (fl.l_start == ftell(mp->keyfile))
return; /* still at EOF */
fclose(mp->keyfile);
if (skeylookup(mp, user) != 1)
errx(1, "user %s already added", user);
goto dolock;
}
void
secure_mode(count, key, seed, defaultseed, buf, bufsiz)
int *count;
char *key;
char *seed;
char *defaultseed;
char *buf;
size_t bufsiz;
{
int i, n;
char *p;
(void)puts("You need the 6 words generated from the \"skey\" command.");
for (i = 0; ; i++) {
if (i >= 2)
exit(1);
(void)printf("Enter sequence count from 1 to %d: ",
SKEY_MAX_SEQ);
(void)fgets(buf, bufsiz, stdin);
clearerr(stdin);
n = atoi(buf);
if (n > 0 && n < SKEY_MAX_SEQ)
break; /* Valid range */
(void)fprintf(stderr, "ERROR: Count must be between 1 and %d\n",
SKEY_MAX_SEQ);
}
for (i = 0; ; i++) {
if (i >= 2)
exit(1);
(void)printf("Enter new seed [default %s]: ",
defaultseed);
(void)fgets(seed, SKEY_MAX_SEED_LEN+2, stdin); /* XXX */
clearerr(stdin);
rip(seed);
if (strlen(seed) > SKEY_MAX_SEED_LEN) {
(void)fprintf(stderr, "ERROR: Seed must be between 1 "
"and %d characters in length\n", SKEY_MAX_SEED_LEN);
continue;
}
if (seed[0] == '\0')
(void)strcpy(seed, defaultseed);
for (p = seed; *p; p++) {
if (isspace(*p)) {
(void)fputs("ERROR: Seed must not contain "
"any spaces\n", stderr);
break;
} else if (isalpha(*p)) {
if (isupper(*p))
*p = tolower(*p);
} else if (!isdigit(*p)) {
(void)fputs("ERROR: Seed must be purely "
"alphanumeric\n", stderr);
break;
}
}
if (*p == '\0')
break; /* Valid seed */
}
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, bufsiz, stdin);
clearerr(stdin);
rip(buf);
backspace(buf);
if (buf[0] == '?') {
(void)puts("Enter 6 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)fputs("ERROR: Invalid format - try again with the 6 words.\n",
stderr);
}
*count= n;
}
void
normal_mode(username, n, key, seed, defaultseed)
char *username;
int n;
char *key;
char *seed;
char *defaultseed;
{
int i, nn;
char passwd[SKEY_MAX_PW_LEN+2], passwd2[SKEY_MAX_PW_LEN+2];
/* Get user's secret passphrase */
for (i = 0; ; i++) {
if (i > 2)
exit(1);
if (readpassphrase("Enter secret passphrase: ", passwd,
sizeof(passwd), 0) == NULL || passwd[0] == '\0')
exit(1);
if (strlen(passwd) < SKEY_MIN_PW_LEN) {
(void)fprintf(stderr,
"ERROR: Your passphrase must be at least %d "
"characters long.\n", SKEY_MIN_PW_LEN);
continue;
} else if (strcmp(passwd, username) == 0) {
(void)fputs("ERROR: Your passphrase may not be the "
"same as your user name.\n", stderr);
continue;
} else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") ==
strlen(passwd)) {
(void)fputs("ERROR: Your passphrase must contain more "
"than just lower case letters.\nWhitespace, "
"numbers, and puctuation are suggested.\n", stderr);
continue;
} else if (strlen(passwd) > 63) {
(void)fprintf(stderr, "WARNING: Your passphrase is "
"longer than the recommended maximum length of 63\n");
}
/* XXX - should check for passphrase that is really too long */
if (readpassphrase("Again secret passphrase: ", passwd2,
sizeof(passwd2), 0) && strcmp(passwd, passwd2) == 0)
break;
(void)fputs("Passphrases do not match.\n", stderr);
}
/* Crunch seed and passphrase 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);
}
#define TIMEOUT_MSG "Timed out waiting for input.\n"
void
timedout(signo)
int signo;
{
write(STDERR_FILENO, TIMEOUT_MSG, sizeof(TIMEOUT_MSG) - 1);
_exit(1);
}
void
usage(s)
char *s;
{
(void)fprintf(stderr,
"Usage: %s [-s] [-x] [-z] [-n count] [-md4|-md5|-sha1|-rmd160] [user]\n", s);
exit(1);
}