usr.bin/skey/skey.c

   1 /*      $NetBSD: skey.c,v 1.16 2004/01/05 23:23:36 jmmv Exp $   */
   2
   3 /*
   4  * S/KEY v1.1b (skey.c)
   5  *
   6  * Authors:
   7  *          Neil M. Haller <nmh@thumper.bellcore.com>
   8  *          Philip R. Karn <karn@chicago.qualcomm.com>
   9  *          John S. Walden <jsw@thumper.bellcore.com>
  10  *          Scott Chasin <chasin@crimelab.com>
  11  *
  12  *
  13  * Stand-alone program for computing responses to S/Key challenges.
  14  * Takes the iteration count and seed as command line args, prompts
  15  * for the user's key, and produces both word and hex format responses.
  16  *
  17  * Usage example:
  18  *      >skey 88 ka9q2
  19  *      Enter password:
  20  *      OMEN US HORN OMIT BACK AHOY
  21  *      >
  22  */
  23
  24 #include <sys/cdefs.h>
  25 #ifndef lint
  26 __RCSID("$NetBSD: skey.c,v 1.16 2004/01/05 23:23:36 jmmv Exp $");
  27 #endif
  28
  29 #include <ctype.h>
  30 #include <err.h>
  31 #include <fcntl.h>
  32 #include <stdio.h>
  33 #include <skey.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <unistd.h>
  37
  38 int     main(int, char **);
  39 void    usage(char *);
  40
  41 int
  42 main(int        argc, char **argv)
  43 {
  44         int     n, cnt, i, pass = 0, hexmode = 0;
  45         char    passwd[SKEY_MAX_PW_LEN+1], key[SKEY_BINKEY_SIZE];
  46         char    buf[33], *seed, *slash, *t;
  47
  48         cnt = 1;
  49
  50         while ((i = getopt(argc, argv, "fn:p:t:x")) != -1) {
  51                 switch (i) {
  52                 case 'f':
  53                                 /* this option is ignored now */
  54                         break;
  55                 case 'n':
  56                         cnt = atoi(optarg);
  57                         break;
  58                 case 'p':
  59                         if (strlcpy(passwd, optarg, sizeof(passwd)) >=
  60                                                         sizeof(passwd))
  61                                 errx(1, "Password too long");
  62                         pass = 1;
  63                         break;
  64                 case 't':
  65                         if (skey_set_algorithm(optarg) == NULL) {
  66                                 errx(1, "Unknown hash algorithm %s", optarg);
  67                         }
  68                         break;
  69                 case 'x':
  70                         hexmode = 1;
  71                         break;
  72                 default:
  73                         usage(argv[0]);
  74                         break;
  75                 }
  76         }
  77
  78         /* could be in the form <number>/<seed> */
  79         if (argc <= optind + 1) {
  80                 /* look for / in it */
  81                 if (argc <= optind)
  82                         usage(argv[0]);
  83                 slash = strchr(argv[optind], '/');
  84                 if (slash == NULL)
  85                         usage(argv[0]);
  86                 *slash++ = '\0';
  87                 seed = slash;
  88
  89                 if ((n = atoi(argv[optind])) < 0) {
  90                         fprintf(stderr, "%s not positive\n", argv[optind]);
  91                         usage(argv[0]);
  92                 } else if (n > SKEY_MAX_SEQ) {
  93                         warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
  94                         usage(argv[0]);
  95                 }
  96         } else {
  97
  98                 if ((n = atoi(argv[optind])) < 0) {
  99                         fprintf(stderr, "%s not positive\n", argv[optind]);
 100                         usage(argv[0]);
 101                 } else if (n > SKEY_MAX_SEQ) {
 102                         warnx("%d is larger than max (%d)", n, SKEY_MAX_SEQ);
 103                         usage(argv[0]);
 104                 }
 105                 seed = argv[++optind];
 106         }
 107
 108         for(t = seed; *t; t++) {
 109                 if(!isalnum((unsigned char)*t))
 110                         errx(1, "seed must be alphanumeric");
 111         }
 112
 113         if(!*seed || strlen(seed) > SKEY_MAX_SEED_LEN)
 114                 errx(1, "seed must be between 1 and %d long", SKEY_MAX_SEED_LEN);
 115
 116         /* Get user's secret password */
 117         if (!pass) {
 118                 (void)fputs("Reminder - Do not use this program while "
 119                             "logged in via telnet or rlogin.\n", stderr);
 120                 fprintf(stderr, "Enter secret password: ");
 121                 readpass(passwd, sizeof(passwd));
 122                 if (passwd[0] == '\0')
 123                         exit(1);
 124         }
 125
 126         if (strlen(passwd) < SKEY_MIN_PW_LEN)
 127                 warnx(
 128         "password should be at least %d characters long according to RFC2289",
 129                     SKEY_MIN_PW_LEN);
 130
 131         /* Crunch seed and password into starting key */
 132         if (keycrunch(key, seed, passwd) != 0)
 133                 errx(1, "key crunch failed");
 134
 135         if (cnt == 1) {
 136                 while (n-- != 0)
 137                         f(key);
 138                 (void)puts(hexmode ? put8(buf, key) : btoe(buf, key));
 139         } else {
 140                 for (i = 0; i <= n - cnt; i++)
 141                         f(key);
 142                 for (; i <= n; i++) {
 143                         (void)printf("%3d: %-29s", i, btoe(buf, key));
 144                         if (hexmode)
 145                                 (void)printf("\t%s", put8(buf, key));
 146                         puts("");
 147                         f(key);
 148                 }
 149         }
 150         exit(0);
 151 }
 152
 153 void
 154 usage(char *s)
 155 {
 156
 157         fprintf(stderr,
 158     "usage: %s [-n count] [-p password] [-t hash] [-x] sequence# [/] key\n",
 159             s);
 160         exit(1);
 161 }