384 lines
9.6 KiB
C
384 lines
9.6 KiB
C
/* $NetBSD: skeyinit.c,v 1.29 2009/04/14 09:53:08 lukem Exp $ */
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/* S/KEY v1.1b (skeyinit.c)
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*
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* Authors:
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* Neil M. Haller <nmh@thumper.bellcore.com>
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* Philip R. Karn <karn@chicago.qualcomm.com>
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* John S. Walden <jsw@thumper.bellcore.com>
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* Scott Chasin <chasin@crimelab.com>
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*
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* Modifications:
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* Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* S/KEY initialization and seed update
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: skeyinit.c,v 1.29 2009/04/14 09:53:08 lukem Exp $");
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#endif
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <skey.h>
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#ifndef SKEY_NAMELEN
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#define SKEY_NAMELEN 4
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#endif
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int main(int argc, char **argv)
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{
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int rval, nn, i;
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size_t l;
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int n = 0, defaultsetup = 1, zerokey = 0, hexmode = 0;
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int argpass = 0, argkey = 0;
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time_t now;
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char hostname[MAXHOSTNAMELEN + 1];
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char seed[SKEY_MAX_PW_LEN+2], key[SKEY_BINKEY_SIZE], defaultseed[SKEY_MAX_SEED_LEN+1];
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char passwd[SKEY_MAX_PW_LEN+2], passwd2[SKEY_MAX_PW_LEN+2], tbuf[27], buf[80];
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char lastc, me[LOGIN_NAME_MAX+1], *p, *pw, *ht = NULL;
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const char *salt;
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struct skey skey;
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struct passwd *pp;
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struct tm *tm;
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int c;
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pw = NULL; /* XXX gcc -Wuninitialized [sh3] */
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/*
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* Make sure using stdin/stdout/stderr is safe
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* after opening any file.
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*/
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i = open(_PATH_DEVNULL, O_RDWR);
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while (i >= 0 && i < 2)
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i = dup(i);
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if (i > 2)
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close(i);
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if (geteuid() != 0)
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errx(1, "must be setuid root.");
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if (gethostname(hostname, sizeof(hostname)) < 0)
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err(1, "gethostname");
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/*
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* Copy the hostname into the default seed, eliminating any
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* non alpha-numeric characters.
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*/
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for (i = 0, l = 0; l < sizeof(defaultseed); i++) {
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if (hostname[i] == '\0') {
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defaultseed[l] = hostname[i];
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break;
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}
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if (isalnum((unsigned char)hostname[i]))
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defaultseed[l++] = hostname[i];
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}
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defaultseed[SKEY_NAMELEN] = '\0';
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(void)time(&now);
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(void)snprintf(tbuf, sizeof(tbuf), "%05ld", (long) (now % 100000));
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(void)strlcat(defaultseed, tbuf, sizeof(defaultseed));
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if ((pp = getpwuid(getuid())) == NULL)
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err(1, "no user with uid %ld", (u_long)getuid());
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(void)strlcpy(me, pp->pw_name, sizeof(me));
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if ((pp = getpwnam(me)) == NULL)
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err(1, "Who are you?");
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salt = pp->pw_passwd;
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while((c = getopt(argc, argv, "k:n:p:t:sxz")) != -1) {
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switch(c) {
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case 'k':
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argkey = 1;
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if (strlen(optarg) > SKEY_MAX_PW_LEN)
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errx(1, "key too long");
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strlcpy(passwd, optarg, sizeof(passwd));
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strlcpy(passwd2, optarg, sizeof(passwd));
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break;
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case 'n':
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n = atoi(optarg);
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if(n < 1 || n > SKEY_MAX_SEQ)
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errx(1, "count must be between 1 and %d", SKEY_MAX_SEQ);
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break;
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case 'p':
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if (strlen(optarg) >= _PASSWORD_LEN)
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errx(1, "password too long");
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if ((pw = malloc(_PASSWORD_LEN + 1)) == NULL)
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err(1, "no memory for password");
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strlcpy(pw, optarg, _PASSWORD_LEN + 1);
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break;
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case 't':
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if(skey_set_algorithm(optarg) == NULL)
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errx(1, "Unknown hash algorithm %s", optarg);
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ht = optarg;
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break;
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case 's':
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defaultsetup = 0;
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break;
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case 'x':
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hexmode = 1;
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break;
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case 'z':
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zerokey = 1;
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break;
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default:
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errx(1, "usage: %s skeyinit [-sxz] [-k passphrase] "
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"[-n count] [-p password] [-t hash] [user]",
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argv[0]);
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}
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}
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if(argc > optind) {
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pp = getpwnam(argv[optind]);
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if (pp == NULL)
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errx(1, "User %s unknown", argv[optind]);
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}
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if (strcmp(pp->pw_name, me) != 0) {
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if (getuid() != 0) {
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/* Only root can change other's passwds */
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errx(1, "Permission denied.");
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}
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}
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if (getuid() != 0) {
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if (!argpass)
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pw = getpass("Password:");
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p = crypt(pw, salt);
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if (strcmp(p, pp->pw_passwd)) {
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errx(1, "Password incorrect.");
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}
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}
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rval = skeylookup(&skey, pp->pw_name);
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switch (rval) {
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case -1:
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err(1, "cannot open database");
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case 0:
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/* comment out user if asked to */
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if (zerokey)
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exit(skeyzero(&skey, pp->pw_name));
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printf("[Updating %s]\n", pp->pw_name);
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printf("Old key: [%s] %s\n", skey_get_algorithm(), skey.seed);
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/*
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* lets be nice if they have a skey.seed that
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* ends in 0-8 just add one
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*/
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l = strlen(skey.seed);
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if (l > 0) {
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lastc = skey.seed[l - 1];
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if (isdigit((unsigned char)lastc) && lastc != '9') {
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(void)strlcpy(defaultseed, skey.seed,
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sizeof(defaultseed));
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defaultseed[l - 1] = lastc + 1;
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}
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if (isdigit((unsigned char)lastc) && lastc == '9' &&
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l < 16) {
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(void)strlcpy(defaultseed, skey.seed,
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sizeof(defaultseed));
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defaultseed[l - 1] = '0';
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defaultseed[l] = '0';
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defaultseed[l + 1] = '\0';
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}
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}
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break;
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case 1:
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if (zerokey)
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errx(1, "You have no entry to zero.");
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printf("[Adding %s]\n", pp->pw_name);
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break;
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}
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if (n==0)
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n = 100;
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/* Set hash type if asked to */
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if (ht) {
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/* Need to zero out old key when changing algorithm */
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if (strcmp(ht, skey_get_algorithm()) && skey_set_algorithm(ht))
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zerokey = 1;
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}
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if (!defaultsetup) {
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printf("You need the 6 english words generated from the \"skey\" command.\n");
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for (i = 0;; i++) {
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if (i >= 2)
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exit(1);
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printf("Enter sequence count from 1 to %d: ", SKEY_MAX_SEQ);
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fgets(buf, sizeof(buf), stdin);
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n = atoi(buf);
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if (n > 0 && n < SKEY_MAX_SEQ)
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break; /* Valid range */
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printf("\nError: Count must be between 0 and %d\n", SKEY_MAX_SEQ);
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}
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for (i = 0;; i++) {
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if (i >= 2)
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exit(1);
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printf("Enter new seed [default %s]: ", defaultseed);
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fflush(stdout);
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fgets(seed, sizeof(seed), stdin);
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rip(seed);
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for (p = seed; *p; p++) {
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if (isalpha((unsigned char)*p)) {
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*p = tolower((unsigned char)*p);
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} else if (!isdigit((unsigned char)*p)) {
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(void)puts("Error: seed may only contain alphanumeric characters");
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break;
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}
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}
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if (*p == '\0')
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break; /* Valid seed */
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}
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if (strlen(seed) > SKEY_MAX_SEED_LEN) {
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printf("Notice: Seed truncated to %d characters.\n", SKEY_MAX_SEED_LEN);
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seed[SKEY_MAX_SEED_LEN] = '\0';
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}
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if (seed[0] == '\0')
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(void)strlcpy(seed, defaultseed, sizeof(seed));
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for (i = 0;; i++) {
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if (i >= 2)
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exit(1);
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printf("otp-%s %d %s\ns/key access password: ",
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skey_get_algorithm(), n, seed);
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fgets(buf, sizeof(buf), stdin);
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rip(buf);
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backspace(buf);
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if (buf[0] == '?') {
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puts("Enter 6 English words from secure S/Key calculation.");
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continue;
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} else if (buf[0] == '\0') {
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exit(1);
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}
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if (etob(key, buf) == 1 || atob8(key, buf) == 0)
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break; /* Valid format */
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(void)puts("Invalid format - try again with 6 English words.");
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}
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} else {
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/* Get user's secret password */
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puts("Reminder - Only use this method if you are directly connected\n"
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" or have an encrypted channel. If you are using telnet\n"
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" or rlogin, exit with no password and use skeyinit -s.\n");
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for (i = 0;; i++) {
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if (i >= 2)
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exit(1);
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if (!argkey) {
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printf("Enter secret password: ");
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readpass(passwd, sizeof(passwd));
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if (passwd[0] == '\0')
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exit(1);
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}
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if (strlen(passwd) < SKEY_MIN_PW_LEN) {
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(void)fprintf(stderr,
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"Your password must be at least %d characters long.\n", SKEY_MIN_PW_LEN);
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continue;
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} else if (strcmp(passwd, pp->pw_name) == 0) {
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(void)fputs("Your password may not be the same as your user name.\n", stderr);
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continue;
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}
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#if 0
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else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") == strlen(passwd)) {
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(void)fputs("Your password must contain more than just lower case letters.\n"
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"Whitespace, numbers, and puctuation are suggested.\n", stderr);
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continue;
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}
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#endif
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if (!argkey) {
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printf("Again secret password: ");
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readpass(passwd2, sizeof(passwd));
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if (passwd2[0] == '\0')
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exit(1);
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}
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if (strcmp(passwd, passwd2) == 0)
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break;
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puts("Passwords do not match.");
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}
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/* Crunch seed and password into starting key */
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(void)strlcpy(seed, defaultseed, sizeof(seed));
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if (keycrunch(key, seed, passwd) != 0)
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err(2, "key crunch failed");
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nn = n;
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while (nn-- != 0)
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f(key);
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}
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(void)time(&now);
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tm = localtime(&now);
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(void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm);
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if ((skey.val = (char *)malloc(16 + 1)) == NULL)
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err(1, "Can't allocate memory");
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/* Zero out old key if necessary (entry would change size) */
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if (zerokey) {
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(void)skeyzero(&skey, pp->pw_name);
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/* Re-open keys file and seek to the end */
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if (skeylookup(&skey, pp->pw_name) == -1)
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err(1, "cannot open database");
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}
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btoa8(skey.val, key);
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/*
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* Obtain an exclusive lock on the key file so we don't
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* clobber someone authenticating themselves at the same time.
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*/
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for (i = 0; i < 300; i++) {
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if ((rval = flock(fileno(skey.keyfile), LOCK_EX|LOCK_NB)) == 0
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|| errno != EWOULDBLOCK)
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break;
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usleep(100000); /* Sleep for 0.1 seconds */
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}
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if (rval == -1) { /* Can't get exclusive lock */
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errno = EAGAIN;
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err(1, "cannot open database");
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}
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/* Don't save algorithm type for md4 (keep record length same) */
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if (strcmp(skey_get_algorithm(), "md4") == 0)
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(void)fprintf(skey.keyfile, "%s %04d %-16s %s %-21s\n",
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pp->pw_name, n, seed, skey.val, tbuf);
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else
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(void)fprintf(skey.keyfile, "%s %s %04d %-16s %s %-21s\n",
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pp->pw_name, skey_get_algorithm(), n, seed, skey.val, tbuf);
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(void)fclose(skey.keyfile);
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(void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name,
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skey_get_algorithm(), n, seed);
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(void)printf("Next login password: %s\n\n",
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hexmode ? put8(buf, key) : btoe(buf, key));
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return(0);
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}
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