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skeyinit.c revision 1.12.10.2 
      1 /*	$NetBSD: skeyinit.c,v 1.12.10.2 2001/04/25 12:26:53 he Exp $	*/
      2 
      3 /* S/KEY v1.1b (skeyinit.c)
      4  *
      5  * Authors:
      6  *          Neil M. Haller <nmh (at) thumper.bellcore.com>
      7  *          Philip R. Karn <karn (at) chicago.qualcomm.com>
      8  *          John S. Walden <jsw (at) thumper.bellcore.com>
      9  *          Scott Chasin <chasin (at) crimelab.com>
     10  *
     11  * Modifications:
     12  *          Todd C. Miller <Todd.Miller (at) courtesan.com>
     13  *
     14  * S/KEY initialization and seed update
     15  */
     16 
     17 #include <sys/param.h>
     18 #include <sys/time.h>
     19 #include <sys/resource.h>
     20 
     21 #include <ctype.h>
     22 #include <err.h>
     23 #include <errno.h>
     24 #include <fcntl.h>
     25 #include <pwd.h>
     26 #include <stdio.h>
     27 #include <stdlib.h>
     28 #include <string.h>
     29 #include <time.h>
     30 #include <unistd.h>
     31 #include <utmp.h>
     32 
     33 #include <skey.h>
     34 
     35 #ifndef SKEY_NAMELEN
     36 #define SKEY_NAMELEN    4
     37 #endif
     38 
     39 int main __P((int, char **));
     40 
     41 int main(int argc, char **argv)
     42 {
     43 	int     rval, nn, i, l;
     44 	int n = 0, defaultsetup = 1, zerokey = 0, hexmode = 0;
     45 	time_t  now;
     46 	char	hostname[MAXHOSTNAMELEN + 1];
     47 	char    seed[SKEY_MAX_PW_LEN+2], key[SKEY_BINKEY_SIZE], defaultseed[SKEY_MAX_SEED_LEN+1];
     48 	char    passwd[SKEY_MAX_PW_LEN+2], passwd2[SKEY_MAX_PW_LEN+2], tbuf[27], buf[80];
     49 	char    lastc, me[UT_NAMESIZE+1], *p, *pw, *ht = NULL;
     50 	const	char *salt;
     51 	struct	skey skey;
     52 	struct	passwd *pp;
     53 	struct	tm *tm;
     54 	int c;
     55 
     56 	if (geteuid() != 0)
     57 		errx(1, "must be setuid root.");
     58 
     59 	if (gethostname(hostname, sizeof(hostname)) < 0)
     60 		err(1, "gethostname");
     61 	(void)strncpy(defaultseed, hostname, sizeof(defaultseed)- 1);
     62 	defaultseed[SKEY_NAMELEN] = '\0';
     63 	(void)time(&now);
     64 	(void)sprintf(tbuf, "%05ld", (long) (now % 100000));
     65 	(void)strncat(defaultseed, tbuf, sizeof(defaultseed) - 5);
     66 
     67 	if ((pp = getpwuid(getuid())) == NULL)
     68 		err(1, "no user with uid %ld", (u_long)getuid());
     69 	(void)strncpy(me, pp->pw_name, sizeof(me) - 1);
     70 	me[sizeof(me) - 1] = '\0';
     71 
     72 	if ((pp = getpwnam(me)) == NULL)
     73 		err(1, "Who are you?");
     74 	salt = pp->pw_passwd;
     75 
     76 	while((c = getopt(argc, argv, "n:t:sxz")) != -1) {
     77 		switch(c) {
     78 			case 'n':
     79 				n = atoi(optarg);
     80 				if(n < 1 || n > SKEY_MAX_SEQ)
     81 					errx(1, "count must be between 1 and %d", SKEY_MAX_SEQ);
     82 				break;
     83 			case 't':
     84 				if(skey_set_algorithm(optarg) == NULL)
     85 					errx(1, "Unknown hash algorithm %s", optarg);
     86 				ht = optarg;
     87 				break;
     88 			case 's':
     89 				defaultsetup = 0;
     90 				break;
     91 			case 'x':
     92 				hexmode = 1;
     93 				break;
     94 			case 'z':
     95 				zerokey = 1;
     96 				break;
     97 			default:
     98 				err(1, "Usage: %s [-n count] [-t md4|md5|sha1] [-s] [-x] [-z] [user]\n", argv[0]);
     99 		}
    100 	}
    101 
    102 	if(argc > optind) {
    103 		pp = getpwnam(argv[optind]);
    104 		if (pp == NULL)
    105 			errx(1, "User %s unknown", argv[optind]);
    106 		}
    107 
    108 	if (strcmp(pp->pw_name, me) != 0) {
    109 		if (getuid() != 0) {
    110 			/* Only root can change other's passwds */
    111 			errx(1, "Permission denied.");
    112 		}
    113 	}
    114 
    115 	if (getuid() != 0) {
    116 		pw = getpass("Password:");
    117 		p = crypt(pw, salt);
    118 
    119 		if (strcmp(p, pp->pw_passwd)) {
    120 			errx(1, "Password incorrect.");
    121 		}
    122 	}
    123 
    124 	rval = skeylookup(&skey, pp->pw_name);
    125 	switch (rval) {
    126 	case -1:
    127 		err(1, "cannot open database");
    128 	case 0:
    129 		/* comment out user if asked to */
    130 		if (zerokey)
    131 			exit(skeyzero(&skey, pp->pw_name));
    132 
    133 		printf("[Updating %s]\n", pp->pw_name);
    134 		printf("Old key: [%s] %s\n", skey_get_algorithm(), skey.seed);
    135 
    136 		/*
    137 		 * lets be nice if they have a skey.seed that
    138 		 * ends in 0-8 just add one
    139 		 */
    140 		l = strlen(skey.seed);
    141 		if (l > 0) {
    142 			lastc = skey.seed[l - 1];
    143 			if (isdigit((unsigned char)lastc) && lastc != '9') {
    144 				(void)strncpy(defaultseed, skey.seed,
    145 				    sizeof(defaultseed) - 1);
    146 				defaultseed[l - 1] = lastc + 1;
    147 			}
    148 			if (isdigit((unsigned char)lastc) && lastc == '9' &&
    149 			    l < 16) {
    150 				(void)strncpy(defaultseed, skey.seed,
    151 				    sizeof(defaultseed) - 1);
    152 				defaultseed[l - 1] = '0';
    153 				defaultseed[l] = '0';
    154 				defaultseed[l + 1] = '\0';
    155 			}
    156 		}
    157 		break;
    158 	case 1:
    159 		if (zerokey)
    160 			errx(1, "You have no entry to zero.");
    161 		printf("[Adding %s]\n", pp->pw_name);
    162 		break;
    163 	}
    164 
    165 	if(n==0)
    166 		n = 99;
    167 
    168 	/* Set hash type if asked to */
    169 	if (ht) {
    170 		/* Need to zero out old key when changing algorithm */
    171 		if (strcmp(ht, skey_get_algorithm()) && skey_set_algorithm(ht))
    172 			zerokey = 1;
    173 	}
    174 
    175 	if (!defaultsetup) {
    176 		printf("You need the 6 english words generated from the \"skey\" command.\n");
    177 		for (i = 0;; i++) {
    178 			if (i >= 2)
    179 				exit(1);
    180 			printf("Enter sequence count from 1 to %d: ", SKEY_MAX_SEQ);
    181 			fgets(buf, sizeof(buf), stdin);
    182 			n = atoi(buf);
    183 			if (n > 0 && n < SKEY_MAX_SEQ)
    184 				break;	/* Valid range */
    185 			printf("\nError: Count must be between 0 and %d\n", SKEY_MAX_SEQ);
    186 		}
    187 
    188 		for (i = 0;; i++) {
    189 			if (i >= 2)
    190 				exit(1);
    191 
    192 			printf("Enter new seed [default %s]: ", defaultseed);
    193 			fflush(stdout);
    194 			fgets(seed, sizeof(seed), stdin);
    195 			rip(seed);
    196 			for (p = seed; *p; p++) {
    197 				if (isalpha(*p)) {
    198 					if (isupper(*p))
    199 						*p = tolower(*p);
    200 				} else if (!isdigit(*p)) {
    201 					(void)puts("Error: seed may only contain alphanumeric characters");
    202 					break;
    203 				}
    204 			}
    205 			if (*p == '\0')
    206 				break;  /* Valid seed */
    207 		}
    208 		if (strlen(seed) > SKEY_MAX_SEED_LEN) {
    209 			printf("Notice: Seed truncated to %d characters.\n", SKEY_MAX_SEED_LEN);
    210 			seed[SKEY_MAX_SEED_LEN] = '\0';
    211 		}
    212 		if (seed[0] == '\0')
    213 			(void)strcpy(seed, defaultseed);
    214 
    215 		for (i = 0;; i++) {
    216 			if (i >= 2)
    217 				exit(1);
    218 
    219 			printf("otp-%s %d %s\ns/key access password: ",
    220 				skey_get_algorithm(), n, seed);
    221 			fgets(buf, sizeof(buf), stdin);
    222 			rip(buf);
    223 			backspace(buf);
    224 
    225 			if (buf[0] == '?') {
    226 				puts("Enter 6 English words from secure S/Key calculation.");
    227 				continue;
    228 			} else if (buf[0] == '\0') {
    229 				exit(1);
    230 			}
    231 			if (etob(key, buf) == 1 || atob8(key, buf) == 0)
    232 				break;	/* Valid format */
    233 			(void)puts("Invalid format - try again with 6 English words.");
    234 		}
    235 	} else {
    236 	/* Get user's secret password */
    237 	puts("Reminder - Only use this method if you are directly connected\n"
    238 	      "           or have an encrypted channel. If you are using telnet\n"
    239 	      "           or rlogin, exit with no password and use skeyinit -s.\n");
    240 
    241 	for (i = 0;; i++) {
    242 			if (i >= 2)
    243 				exit(1);
    244 
    245 			printf("Enter secret password: ");
    246 			readpass(passwd, sizeof(passwd));
    247 			if (passwd[0] == '\0')
    248 				exit(1);
    249 
    250 			if (strlen(passwd) < SKEY_MIN_PW_LEN) {
    251 				(void)fprintf(stderr,
    252 				    "Your password must be at least %d characters long.\n", SKEY_MIN_PW_LEN);
    253 				continue;
    254 			} else if (strcmp(passwd, pp->pw_name) == 0) {
    255 				(void)fputs("Your password may not be the same as your user name.\n", stderr);
    256 				continue;
    257 			}
    258 #if 0
    259 			else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") == strlen(passwd)) {
    260 				(void)fputs("Your password must contain more than just lower case letters.\n"
    261 					    "Whitespace, numbers, and puctuation are suggested.\n", stderr);
    262 				continue;
    263 			}
    264 #endif
    265 			printf("Again secret password: ");
    266 			readpass(passwd2, sizeof(passwd));
    267 			if (passwd2[0] == '\0')
    268 				exit(1);
    269 
    270 			if (strcmp(passwd, passwd2) == 0)
    271 				break;
    272 
    273 			puts("Passwords do not match.");
    274 		}
    275 
    276 		/* Crunch seed and password into starting key */
    277 		(void)strcpy(seed, defaultseed);
    278 		if (keycrunch(key, seed, passwd) != 0)
    279 			err(2, "key crunch failed");
    280 		nn = n;
    281 		while (nn-- != 0)
    282 			f(key);
    283 	}
    284 	(void)time(&now);
    285 	tm = localtime(&now);
    286 	(void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm);
    287 
    288 	if ((skey.val = (char *)malloc(16 + 1)) == NULL)
    289 		err(1, "Can't allocate memory");
    290 
    291 	/* Zero out old key if necesary (entry would change size) */
    292 	if (zerokey) {
    293 		(void)skeyzero(&skey, pp->pw_name);
    294 		/* Re-open keys file and seek to the end */
    295 		if (skeylookup(&skey, pp->pw_name) == -1)
    296 			err(1, "cannot open database");
    297 	}
    298 
    299 	btoa8(skey.val, key);
    300 
    301 	/*
    302 	 * Obtain an exclusive lock on the key file so we don't
    303 	 * clobber someone authenticating themselves at the same time.
    304 	 */
    305 	for (i = 0; i < 300; i++) {
    306 		if ((rval = flock(fileno(skey.keyfile), LOCK_EX|LOCK_NB)) == 0
    307 		    || errno != EWOULDBLOCK)
    308 			break;
    309 		usleep(100000);			/* Sleep for 0.1 seconds */
    310 	}
    311 	if (rval == -1)	{			/* Can't get exclusive lock */
    312 		errno = EAGAIN;
    313 		err(1, "cannot open database");
    314 	}
    315 
    316 	/* Don't save algorithm type for md4 (keep record length same) */
    317 	if (strcmp(skey_get_algorithm(), "md4") == 0)
    318 		(void)fprintf(skey.keyfile, "%s %04d %-16s %s %-21s\n",
    319 		    pp->pw_name, n, seed, skey.val, tbuf);
    320 	else
    321 		(void)fprintf(skey.keyfile, "%s %s %04d %-16s %s %-21s\n",
    322 		    pp->pw_name, skey_get_algorithm(), n, seed, skey.val, tbuf);
    323 
    324 	(void)fclose(skey.keyfile);
    325 
    326 	(void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name,
    327 		     skey_get_algorithm(), n, seed);
    328 	(void)printf("Next login password: %s\n\n",
    329 		     hexmode ? put8(buf, key) : btoe(buf, key));
    330 
    331 	return(0);
    332 }
    333