#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.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 <limits.h>
#include <utmp.h>
#include <skey.h>
#include <bsd_auth.h>
#ifndef SKEY_NAMELEN
#define SKEY_NAMELEN 4
#endif
void usage(void);
void secure_mode(int *, char *, char *, size_t, char *, size_t);
void normal_mode(char *, int, char *, char *);
void enable_db(int);
int
main(int argc, char **argv)
{
int rval, i, l, n, defaultsetup, rmkey, hexmode, enable;
char hostname[HOST_NAME_MAX+1];
char seed[SKEY_MAX_SEED_LEN + 1];
char buf[256], key[SKEY_BINKEY_SIZE], filename[PATH_MAX], *ht;
char lastc, *p, *auth_type;
const char *errstr;
struct skey skey;
struct passwd *pp;
n = rmkey = hexmode = enable = 0;
defaultsetup = 1;
ht = auth_type = NULL;
for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
if (argv[i][2] == '\0') {
switch (argv[i][1]) {
case 'a':
if (argv[++i] == NULL || argv[i][0] == '\0')
usage();
auth_type = argv[i];
break;
case 's':
defaultsetup = 0;
if (auth_type == NULL)
auth_type = "skey";
break;
case 'x':
hexmode = 1;
break;
case 'r':
rmkey = 1;
break;
case 'n':
if (argv[++i] == NULL || argv[i][0] == '\0')
usage();
n = strtonum(argv[i], 1, SKEY_MAX_SEQ - 1, &errstr);
if (errstr)
errx(1, "count must be > 0 and < %d",
SKEY_MAX_SEQ);
break;
case 'D':
enable = -1;
break;
case 'E':
enable = 1;
break;
default:
usage();
}
} else {
if ((ht = skey_set_algorithm(&argv[i][1])) == NULL) {
warnx("Unknown hash algorithm %s", &argv[i][1]);
usage();
}
}
i++;
}
argv += i;
argc -= i;
if (argc > 1 || (enable && argc))
usage();
if (enable) {
enable_db(enable);
exit(0);
}
if (getuid() != 0) {
if (pledge("stdio rpath wpath cpath fattr flock tty proc exec "
"getpw", NULL) == -1)
err(1, "pledge");
if ((pp = getpwuid(getuid())) == NULL)
err(1, "no user with uid %u", getuid());
if (argc == 1) {
char me[UT_NAMESIZE + 1];
(void)strlcpy(me, pp->pw_name, sizeof me);
if ((pp = getpwnam(argv[0])) == NULL)
errx(1, "User unknown: %s", argv[0]);
if (strcmp(pp->pw_name, me) != 0)
errx(1, "Permission denied.");
}
} else {
if (pledge("stdio rpath wpath cpath fattr flock tty getpw id",
NULL) == -1)
err(1, "pledge");
if (argc == 1) {
if ((pp = getpwnam(argv[0])) == NULL) {
static struct passwd _pp;
_pp.pw_name = argv[0];
pp = &_pp;
warnx("Warning, user unknown: %s", argv[0]);
} else {
if (setresuid(-1, pp->pw_uid, -1) != 0)
errx(1, "unable to change uid to %u",
pp->pw_uid);
}
} else if ((pp = getpwuid(0)) == NULL)
err(1, "no user with uid 0");
if (pledge("stdio rpath wpath cpath fattr flock tty", NULL)
== -1)
err(1, "pledge");
}
switch (skey_haskey(pp->pw_name)) {
case -1:
if (errno == ENOENT || errno == EPERM)
errx(1, "S/Key disabled");
else
err(1, "cannot open database");
break;
case 0:
break;
case 1:
if (!defaultsetup && strcmp(auth_type, "skey") == 0) {
fprintf(stderr,
"You must authenticate yourself before using S/Key for the first time. In\n"
"secure mode this is normally done via an existing S/Key key. However, since\n"
"you do not have an entry in the S/Key database you will have to specify an\n"
"alternate authentication type via the `-a' flag, e.g.\n"
" \"skeyinit -s -a passwd\"\n\n"
"Note that entering a plaintext password over a non-secure link defeats the\n"
"purpose of using S/Key in the fist place.\n");
exit(1);
}
break;
}
if (getuid() != 0) {
if ((pp = pw_dup(pp)) == NULL)
err(1, NULL);
if (!auth_userokay(pp->pw_name, auth_type, NULL, NULL))
errx(1, "Password incorrect");
}
if (pledge("stdio rpath wpath cpath fattr flock tty", NULL) == -1)
err(1, "pledge");
if (gethostname(hostname, sizeof(hostname)) == -1)
err(1, "gethostname");
for (i = 0, p = seed; hostname[i] && i < SKEY_NAMELEN; i++) {
if (isalnum((unsigned char)hostname[i]))
*p++ = tolower((unsigned char)hostname[i]);
}
for (i = 0; i < 5; i++)
*p++ = arc4random_uniform(10) + '0';
*p = '\0';
rval = skeylookup(&skey, pp->pw_name);
switch (rval) {
case -1:
err(1, "cannot open database");
break;
case 0:
if (rmkey) {
if (snprintf(filename, sizeof(filename),
"%s/%s", _PATH_SKEYDIR, pp->pw_name)
>= sizeof(filename))
errc(1, ENAMETOOLONG,
"Cannot remove S/Key entry");
if (unlink(filename) != 0)
err(1, "Cannot remove S/Key entry");
printf("S/Key entry for %s removed.\n",
pp->pw_name);
exit(0);
}
(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);
l = strlen(skey.seed);
for (p = skey.seed; *p; p++) {
if (isalpha((unsigned char)*p)) {
if (isupper((unsigned char)*p))
*p = tolower((unsigned char)*p);
} else if (!isdigit((unsigned char)*p)) {
memmove(p, p + 1, l - (p - skey.seed));
l--;
}
}
if (l > 0) {
lastc = skey.seed[l - 1];
if (isdigit((unsigned char)lastc) &&
lastc != '9') {
(void)strlcpy(seed, skey.seed,
sizeof seed);
seed[l - 1] = lastc + 1;
}
if (isdigit((unsigned char)lastc) &&
lastc == '9' && l < 16) {
(void)strlcpy(seed, skey.seed,
sizeof seed);
seed[l - 1] = '0';
seed[l] = '0';
seed[l + 1] = '\0';
}
}
break;
case 1:
if (rmkey)
errx(1, "You have no entry to remove.");
(void)printf("[Adding %s with %s]\n", pp->pw_name,
ht ? ht : skey_get_algorithm());
if (snprintf(filename, sizeof(filename), "%s/%s",
_PATH_SKEYDIR, pp->pw_name) >= sizeof(filename))
errc(1, ENAMETOOLONG,
"Cannot create S/Key entry");
if ((l = open(filename,
O_RDWR | O_NONBLOCK | O_CREAT | O_TRUNC |O_NOFOLLOW,
S_IRUSR | S_IWUSR)) == -1 ||
flock(l, LOCK_EX) != 0 ||
(skey.keyfile = fdopen(l, "r+")) == NULL)
err(1, "Cannot create S/Key entry");
break;
}
if (fchown(fileno(skey.keyfile), pp->pw_uid, -1) != 0 ||
fchmod(fileno(skey.keyfile), S_IRUSR | S_IWUSR) != 0)
err(1, "can't set owner/mode for %s", pp->pw_name);
if (defaultsetup && n == 0)
n = 100;
if (ht && strcmp(ht, skey_get_algorithm()) != 0)
skey_set_algorithm(ht);
alarm(180);
if (!defaultsetup)
secure_mode(&n, key, seed, sizeof seed, buf, sizeof(buf));
else
normal_mode(pp->pw_name, n, key, seed);
alarm(0);
if ((skey.val = malloc(16 + 1)) == NULL)
err(1, "Can't allocate memory");
btoa8(skey.val, key);
(void)fseek(skey.keyfile, 0L, SEEK_SET);
(void)fprintf(skey.keyfile, "%s\n%s\n%04d\n%s\n%s\n",
pp->pw_name, skey_get_algorithm(), n, seed, skey.val);
(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
secure_mode(int *count, char *key, char *seed, size_t seedlen,
char *buf, size_t bufsiz)
{
char *p, newseed[SKEY_MAX_SEED_LEN + 2];
const char *errstr;
int i, n = *count;
(void)puts("You need the 6 words generated from the \"skey\" command.");
if (n == 0) {
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);
rip(buf);
n = strtonum(buf, 1, SKEY_MAX_SEQ-1, &errstr);
if (!errstr)
break;
fprintf(stderr,
"ERROR: Count must be between 1 and %d\n",
SKEY_MAX_SEQ - 1);
}
*count= n;
}
for (i = 0; ; i++) {
if (i >= 2)
exit(1);
(void)printf("Enter new seed [default %s]: ", seed);
(void)fgets(newseed, sizeof(newseed), stdin);
clearerr(stdin);
rip(newseed);
if (strlen(newseed) > SKEY_MAX_SEED_LEN) {
(void)fprintf(stderr, "ERROR: Seed must be between 1 "
"and %d characters in length\n", SKEY_MAX_SEED_LEN);
continue;
}
for (p = newseed; *p; p++) {
if (isspace((unsigned char)*p)) {
(void)fputs("ERROR: Seed must not contain "
"any spaces\n", stderr);
break;
} else if (isalpha((unsigned char)*p)) {
if (isupper((unsigned char)*p))
*p = tolower((unsigned char)*p);
} else if (!isdigit((unsigned char)*p)) {
(void)fputs("ERROR: Seed must be purely "
"alphanumeric\n", stderr);
break;
}
}
if (*p == '\0')
break;
}
if (newseed[0] != '\0')
(void)strlcpy(seed, newseed, seedlen);
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;
(void)fputs("ERROR: Invalid format - try again with the 6 words.\n",
stderr);
}
}
void
normal_mode(char *username, int n, char *key, char *seed)
{
int i, nn;
char passwd[SKEY_MAX_PW_LEN+2], key2[SKEY_BINKEY_SIZE];
for (i = 0; ; i++) {
if (i > 2)
errx(1, "S/Key entry not updated");
if (readpassphrase("Enter new 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 punctuation 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");
}
nn = keycrunch(key, seed, passwd);
explicit_bzero(passwd, sizeof(passwd));
if (nn != 0)
err(2, "key crunch failed");
if (readpassphrase("Again secret passphrase: ", passwd,
sizeof(passwd), 0) == NULL || passwd[0] == '\0')
exit(1);
nn = keycrunch(key2, seed, passwd);
explicit_bzero(passwd, sizeof(passwd));
if (nn != 0)
err(2, "key crunch failed");
if (memcmp(key, key2, sizeof(key2)) == 0)
break;
(void)fputs("Passphrases do not match.\n", stderr);
}
nn = n;
while (nn-- != 0)
f(key);
}
void
enable_db(int op)
{
if (op == 1) {
if (mkdir(_PATH_SKEYDIR, 01730) != 0 && errno != EEXIST)
err(1, "can't mkdir %s", _PATH_SKEYDIR);
if (chown(_PATH_SKEYDIR, geteuid(), getegid()) != 0)
err(1, "can't chown %s", _PATH_SKEYDIR);
if (chmod(_PATH_SKEYDIR, 01730) != 0)
err(1, "can't chmod %s", _PATH_SKEYDIR);
} else {
if (chmod(_PATH_SKEYDIR, 0) != 0 && errno != ENOENT)
err(1, "can't chmod %s", _PATH_SKEYDIR);
}
}
void
usage(void)
{
extern char *__progname;
(void)fprintf(stderr, "usage: %s [-DErsx] [-a auth-type] [-n count]"
"\n\t[-md5 | -rmd160 | -sha1] [user]\n", __progname);
exit(1);
}
