1 /* $NetBSD: skeyinit.c,v 1.16 2001/07/24 16:43:03 wiz Exp $ */ 2 3 /* S/KEY v1.1b (skeyinit.c) 4 * 5 * Authors: 6 * Neil M. Haller <nmh@thumper.bellcore.com> 7 * Philip R. Karn <karn@chicago.qualcomm.com> 8 * John S. Walden <jsw@thumper.bellcore.com> 9 * Scott Chasin <chasin@crimelab.com> 10 * 11 * Modifications: 12 * Todd C. Miller <Todd.Miller@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 62 /* 63 * Copy the hostname into the default seed, eliminating any 64 * non alpha-numeric characters. 65 */ 66 for (i = 0, l = 0; l < sizeof(defaultseed); i++) { 67 if (hostname[i] == '\0') { 68 defaultseed[l] = hostname[i]; 69 break; 70 } 71 if (isalnum(hostname[i])) 72 defaultseed[l++] = hostname[i]; 73 } 74 75 defaultseed[SKEY_NAMELEN] = '\0'; 76 (void)time(&now); 77 (void)sprintf(tbuf, "%05ld", (long) (now % 100000)); 78 (void)strncat(defaultseed, tbuf, sizeof(defaultseed) - 5); 79 80 if ((pp = getpwuid(getuid())) == NULL) 81 err(1, "no user with uid %ld", (u_long)getuid()); 82 (void)strncpy(me, pp->pw_name, sizeof(me) - 1); 83 me[sizeof(me) - 1] = '\0'; 84 85 if ((pp = getpwnam(me)) == NULL) 86 err(1, "Who are you?"); 87 salt = pp->pw_passwd; 88 89 while((c = getopt(argc, argv, "n:t:sxz")) != -1) { 90 switch(c) { 91 case 'n': 92 n = atoi(optarg); 93 if(n < 1 || n > SKEY_MAX_SEQ) 94 errx(1, "count must be between 1 and %d", SKEY_MAX_SEQ); 95 break; 96 case 't': 97 if(skey_set_algorithm(optarg) == NULL) 98 errx(1, "Unknown hash algorithm %s", optarg); 99 ht = optarg; 100 break; 101 case 's': 102 defaultsetup = 0; 103 break; 104 case 'x': 105 hexmode = 1; 106 break; 107 case 'z': 108 zerokey = 1; 109 break; 110 default: 111 err(1, "Usage: %s [-n count] [-t md4|md5|sha1] [-s] [-x] [-z] [user]\n", argv[0]); 112 } 113 } 114 115 if(argc > optind) { 116 pp = getpwnam(argv[optind]); 117 if (pp == NULL) 118 errx(1, "User %s unknown", argv[optind]); 119 } 120 121 if (strcmp(pp->pw_name, me) != 0) { 122 if (getuid() != 0) { 123 /* Only root can change other's passwds */ 124 errx(1, "Permission denied."); 125 } 126 } 127 128 if (getuid() != 0) { 129 pw = getpass("Password:"); 130 p = crypt(pw, salt); 131 132 if (strcmp(p, pp->pw_passwd)) { 133 errx(1, "Password incorrect."); 134 } 135 } 136 137 rval = skeylookup(&skey, pp->pw_name); 138 switch (rval) { 139 case -1: 140 err(1, "cannot open database"); 141 case 0: 142 /* comment out user if asked to */ 143 if (zerokey) 144 exit(skeyzero(&skey, pp->pw_name)); 145 146 printf("[Updating %s]\n", pp->pw_name); 147 printf("Old key: [%s] %s\n", skey_get_algorithm(), skey.seed); 148 149 /* 150 * lets be nice if they have a skey.seed that 151 * ends in 0-8 just add one 152 */ 153 l = strlen(skey.seed); 154 if (l > 0) { 155 lastc = skey.seed[l - 1]; 156 if (isdigit((unsigned char)lastc) && lastc != '9') { 157 (void)strncpy(defaultseed, skey.seed, 158 sizeof(defaultseed) - 1); 159 defaultseed[l - 1] = lastc + 1; 160 } 161 if (isdigit((unsigned char)lastc) && lastc == '9' && 162 l < 16) { 163 (void)strncpy(defaultseed, skey.seed, 164 sizeof(defaultseed) - 1); 165 defaultseed[l - 1] = '0'; 166 defaultseed[l] = '0'; 167 defaultseed[l + 1] = '\0'; 168 } 169 } 170 break; 171 case 1: 172 if (zerokey) 173 errx(1, "You have no entry to zero."); 174 printf("[Adding %s]\n", pp->pw_name); 175 break; 176 } 177 178 if(n==0) 179 n = 99; 180 181 /* Set hash type if asked to */ 182 if (ht) { 183 /* Need to zero out old key when changing algorithm */ 184 if (strcmp(ht, skey_get_algorithm()) && skey_set_algorithm(ht)) 185 zerokey = 1; 186 } 187 188 if (!defaultsetup) { 189 printf("You need the 6 english words generated from the \"skey\" command.\n"); 190 for (i = 0;; i++) { 191 if (i >= 2) 192 exit(1); 193 printf("Enter sequence count from 1 to %d: ", SKEY_MAX_SEQ); 194 fgets(buf, sizeof(buf), stdin); 195 n = atoi(buf); 196 if (n > 0 && n < SKEY_MAX_SEQ) 197 break; /* Valid range */ 198 printf("\nError: Count must be between 0 and %d\n", SKEY_MAX_SEQ); 199 } 200 201 for (i = 0;; i++) { 202 if (i >= 2) 203 exit(1); 204 205 printf("Enter new seed [default %s]: ", defaultseed); 206 fflush(stdout); 207 fgets(seed, sizeof(seed), stdin); 208 rip(seed); 209 for (p = seed; *p; p++) { 210 if (isalpha(*p)) { 211 if (isupper(*p)) 212 *p = tolower(*p); 213 } else if (!isdigit(*p)) { 214 (void)puts("Error: seed may only contain alphanumeric characters"); 215 break; 216 } 217 } 218 if (*p == '\0') 219 break; /* Valid seed */ 220 } 221 if (strlen(seed) > SKEY_MAX_SEED_LEN) { 222 printf("Notice: Seed truncated to %d characters.\n", SKEY_MAX_SEED_LEN); 223 seed[SKEY_MAX_SEED_LEN] = '\0'; 224 } 225 if (seed[0] == '\0') 226 (void)strcpy(seed, defaultseed); 227 228 for (i = 0;; i++) { 229 if (i >= 2) 230 exit(1); 231 232 printf("otp-%s %d %s\ns/key access password: ", 233 skey_get_algorithm(), n, seed); 234 fgets(buf, sizeof(buf), stdin); 235 rip(buf); 236 backspace(buf); 237 238 if (buf[0] == '?') { 239 puts("Enter 6 English words from secure S/Key calculation."); 240 continue; 241 } else if (buf[0] == '\0') { 242 exit(1); 243 } 244 if (etob(key, buf) == 1 || atob8(key, buf) == 0) 245 break; /* Valid format */ 246 (void)puts("Invalid format - try again with 6 English words."); 247 } 248 } else { 249 /* Get user's secret password */ 250 puts("Reminder - Only use this method if you are directly connected\n" 251 " or have an encrypted channel. If you are using telnet\n" 252 " or rlogin, exit with no password and use skeyinit -s.\n"); 253 254 for (i = 0;; i++) { 255 if (i >= 2) 256 exit(1); 257 258 printf("Enter secret password: "); 259 readpass(passwd, sizeof(passwd)); 260 if (passwd[0] == '\0') 261 exit(1); 262 263 if (strlen(passwd) < SKEY_MIN_PW_LEN) { 264 (void)fprintf(stderr, 265 "Your password must be at least %d characters long.\n", SKEY_MIN_PW_LEN); 266 continue; 267 } else if (strcmp(passwd, pp->pw_name) == 0) { 268 (void)fputs("Your password may not be the same as your user name.\n", stderr); 269 continue; 270 } 271 #if 0 272 else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") == strlen(passwd)) { 273 (void)fputs("Your password must contain more than just lower case letters.\n" 274 "Whitespace, numbers, and puctuation are suggested.\n", stderr); 275 continue; 276 } 277 #endif 278 printf("Again secret password: "); 279 readpass(passwd2, sizeof(passwd)); 280 if (passwd2[0] == '\0') 281 exit(1); 282 283 if (strcmp(passwd, passwd2) == 0) 284 break; 285 286 puts("Passwords do not match."); 287 } 288 289 /* Crunch seed and password into starting key */ 290 (void)strcpy(seed, defaultseed); 291 if (keycrunch(key, seed, passwd) != 0) 292 err(2, "key crunch failed"); 293 nn = n; 294 while (nn-- != 0) 295 f(key); 296 } 297 (void)time(&now); 298 tm = localtime(&now); 299 (void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm); 300 301 if ((skey.val = (char *)malloc(16 + 1)) == NULL) 302 err(1, "Can't allocate memory"); 303 304 /* Zero out old key if necessary (entry would change size) */ 305 if (zerokey) { 306 (void)skeyzero(&skey, pp->pw_name); 307 /* Re-open keys file and seek to the end */ 308 if (skeylookup(&skey, pp->pw_name) == -1) 309 err(1, "cannot open database"); 310 } 311 312 btoa8(skey.val, key); 313 314 /* 315 * Obtain an exclusive lock on the key file so we don't 316 * clobber someone authenticating themselves at the same time. 317 */ 318 for (i = 0; i < 300; i++) { 319 if ((rval = flock(fileno(skey.keyfile), LOCK_EX|LOCK_NB)) == 0 320 || errno != EWOULDBLOCK) 321 break; 322 usleep(100000); /* Sleep for 0.1 seconds */ 323 } 324 if (rval == -1) { /* Can't get exclusive lock */ 325 errno = EAGAIN; 326 err(1, "cannot open database"); 327 } 328 329 /* Don't save algorithm type for md4 (keep record length same) */ 330 if (strcmp(skey_get_algorithm(), "md4") == 0) 331 (void)fprintf(skey.keyfile, "%s %04d %-16s %s %-21s\n", 332 pp->pw_name, n, seed, skey.val, tbuf); 333 else 334 (void)fprintf(skey.keyfile, "%s %s %04d %-16s %s %-21s\n", 335 pp->pw_name, skey_get_algorithm(), n, seed, skey.val, tbuf); 336 337 (void)fclose(skey.keyfile); 338 339 (void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name, 340 skey_get_algorithm(), n, seed); 341 (void)printf("Next login password: %s\n\n", 342 hexmode ? put8(buf, key) : btoe(buf, key)); 343 344 return(0); 345 } 346