1 /* $NetBSD: skeyinit.c,v 1.19 2002/08/01 22:43:34 christos 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 <paths.h> 26 #include <pwd.h> 27 #include <stdio.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <time.h> 31 #include <unistd.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[LOGIN_NAME_MAX+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 /* 57 * Make sure using stdin/stdout/stderr is safe 58 * after opening any file. 59 */ 60 i = open(_PATH_DEVNULL, O_RDWR); 61 while (i >= 0 && i < 2) 62 i = dup(i); 63 if (i > 2) 64 close(i); 65 66 if (geteuid() != 0) 67 errx(1, "must be setuid root."); 68 69 if (gethostname(hostname, sizeof(hostname)) < 0) 70 err(1, "gethostname"); 71 72 /* 73 * Copy the hostname into the default seed, eliminating any 74 * non alpha-numeric characters. 75 */ 76 for (i = 0, l = 0; l < sizeof(defaultseed); i++) { 77 if (hostname[i] == '\0') { 78 defaultseed[l] = hostname[i]; 79 break; 80 } 81 if (isalnum(hostname[i])) 82 defaultseed[l++] = hostname[i]; 83 } 84 85 defaultseed[SKEY_NAMELEN] = '\0'; 86 (void)time(&now); 87 (void)sprintf(tbuf, "%05ld", (long) (now % 100000)); 88 (void)strncat(defaultseed, tbuf, sizeof(defaultseed) - 5); 89 90 if ((pp = getpwuid(getuid())) == NULL) 91 err(1, "no user with uid %ld", (u_long)getuid()); 92 (void)strncpy(me, pp->pw_name, sizeof(me) - 1); 93 me[sizeof(me) - 1] = '\0'; 94 95 if ((pp = getpwnam(me)) == NULL) 96 err(1, "Who are you?"); 97 salt = pp->pw_passwd; 98 99 while((c = getopt(argc, argv, "n:t:sxz")) != -1) { 100 switch(c) { 101 case 'n': 102 n = atoi(optarg); 103 if(n < 1 || n > SKEY_MAX_SEQ) 104 errx(1, "count must be between 1 and %d", SKEY_MAX_SEQ); 105 break; 106 case 't': 107 if(skey_set_algorithm(optarg) == NULL) 108 errx(1, "Unknown hash algorithm %s", optarg); 109 ht = optarg; 110 break; 111 case 's': 112 defaultsetup = 0; 113 break; 114 case 'x': 115 hexmode = 1; 116 break; 117 case 'z': 118 zerokey = 1; 119 break; 120 default: 121 errx(1, "Usage: %s [-n count] [-t md4|md5|sha1] [-s] [-x] [-z] [user]", argv[0]); 122 } 123 } 124 125 if(argc > optind) { 126 pp = getpwnam(argv[optind]); 127 if (pp == NULL) 128 errx(1, "User %s unknown", argv[optind]); 129 } 130 131 if (strcmp(pp->pw_name, me) != 0) { 132 if (getuid() != 0) { 133 /* Only root can change other's passwds */ 134 errx(1, "Permission denied."); 135 } 136 } 137 138 if (getuid() != 0) { 139 pw = getpass("Password:"); 140 p = crypt(pw, salt); 141 142 if (strcmp(p, pp->pw_passwd)) { 143 errx(1, "Password incorrect."); 144 } 145 } 146 147 rval = skeylookup(&skey, pp->pw_name); 148 switch (rval) { 149 case -1: 150 err(1, "cannot open database"); 151 case 0: 152 /* comment out user if asked to */ 153 if (zerokey) 154 exit(skeyzero(&skey, pp->pw_name)); 155 156 printf("[Updating %s]\n", pp->pw_name); 157 printf("Old key: [%s] %s\n", skey_get_algorithm(), skey.seed); 158 159 /* 160 * lets be nice if they have a skey.seed that 161 * ends in 0-8 just add one 162 */ 163 l = strlen(skey.seed); 164 if (l > 0) { 165 lastc = skey.seed[l - 1]; 166 if (isdigit((unsigned char)lastc) && lastc != '9') { 167 (void)strncpy(defaultseed, skey.seed, 168 sizeof(defaultseed) - 1); 169 defaultseed[l - 1] = lastc + 1; 170 } 171 if (isdigit((unsigned char)lastc) && lastc == '9' && 172 l < 16) { 173 (void)strncpy(defaultseed, skey.seed, 174 sizeof(defaultseed) - 1); 175 defaultseed[l - 1] = '0'; 176 defaultseed[l] = '0'; 177 defaultseed[l + 1] = '\0'; 178 } 179 } 180 break; 181 case 1: 182 if (zerokey) 183 errx(1, "You have no entry to zero."); 184 printf("[Adding %s]\n", pp->pw_name); 185 break; 186 } 187 188 if(n==0) 189 n = 99; 190 191 /* Set hash type if asked to */ 192 if (ht) { 193 /* Need to zero out old key when changing algorithm */ 194 if (strcmp(ht, skey_get_algorithm()) && skey_set_algorithm(ht)) 195 zerokey = 1; 196 } 197 198 if (!defaultsetup) { 199 printf("You need the 6 english words generated from the \"skey\" command.\n"); 200 for (i = 0;; i++) { 201 if (i >= 2) 202 exit(1); 203 printf("Enter sequence count from 1 to %d: ", SKEY_MAX_SEQ); 204 fgets(buf, sizeof(buf), stdin); 205 n = atoi(buf); 206 if (n > 0 && n < SKEY_MAX_SEQ) 207 break; /* Valid range */ 208 printf("\nError: Count must be between 0 and %d\n", SKEY_MAX_SEQ); 209 } 210 211 for (i = 0;; i++) { 212 if (i >= 2) 213 exit(1); 214 215 printf("Enter new seed [default %s]: ", defaultseed); 216 fflush(stdout); 217 fgets(seed, sizeof(seed), stdin); 218 rip(seed); 219 for (p = seed; *p; p++) { 220 if (isalpha(*p)) { 221 if (isupper(*p)) 222 *p = tolower(*p); 223 } else if (!isdigit(*p)) { 224 (void)puts("Error: seed may only contain alphanumeric characters"); 225 break; 226 } 227 } 228 if (*p == '\0') 229 break; /* Valid seed */ 230 } 231 if (strlen(seed) > SKEY_MAX_SEED_LEN) { 232 printf("Notice: Seed truncated to %d characters.\n", SKEY_MAX_SEED_LEN); 233 seed[SKEY_MAX_SEED_LEN] = '\0'; 234 } 235 if (seed[0] == '\0') 236 (void)strcpy(seed, defaultseed); 237 238 for (i = 0;; i++) { 239 if (i >= 2) 240 exit(1); 241 242 printf("otp-%s %d %s\ns/key access password: ", 243 skey_get_algorithm(), n, seed); 244 fgets(buf, sizeof(buf), stdin); 245 rip(buf); 246 backspace(buf); 247 248 if (buf[0] == '?') { 249 puts("Enter 6 English words from secure S/Key calculation."); 250 continue; 251 } else if (buf[0] == '\0') { 252 exit(1); 253 } 254 if (etob(key, buf) == 1 || atob8(key, buf) == 0) 255 break; /* Valid format */ 256 (void)puts("Invalid format - try again with 6 English words."); 257 } 258 } else { 259 /* Get user's secret password */ 260 puts("Reminder - Only use this method if you are directly connected\n" 261 " or have an encrypted channel. If you are using telnet\n" 262 " or rlogin, exit with no password and use skeyinit -s.\n"); 263 264 for (i = 0;; i++) { 265 if (i >= 2) 266 exit(1); 267 268 printf("Enter secret password: "); 269 readpass(passwd, sizeof(passwd)); 270 if (passwd[0] == '\0') 271 exit(1); 272 273 if (strlen(passwd) < SKEY_MIN_PW_LEN) { 274 (void)fprintf(stderr, 275 "Your password must be at least %d characters long.\n", SKEY_MIN_PW_LEN); 276 continue; 277 } else if (strcmp(passwd, pp->pw_name) == 0) { 278 (void)fputs("Your password may not be the same as your user name.\n", stderr); 279 continue; 280 } 281 #if 0 282 else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") == strlen(passwd)) { 283 (void)fputs("Your password must contain more than just lower case letters.\n" 284 "Whitespace, numbers, and puctuation are suggested.\n", stderr); 285 continue; 286 } 287 #endif 288 printf("Again secret password: "); 289 readpass(passwd2, sizeof(passwd)); 290 if (passwd2[0] == '\0') 291 exit(1); 292 293 if (strcmp(passwd, passwd2) == 0) 294 break; 295 296 puts("Passwords do not match."); 297 } 298 299 /* Crunch seed and password into starting key */ 300 (void)strcpy(seed, defaultseed); 301 if (keycrunch(key, seed, passwd) != 0) 302 err(2, "key crunch failed"); 303 nn = n; 304 while (nn-- != 0) 305 f(key); 306 } 307 (void)time(&now); 308 tm = localtime(&now); 309 (void)strftime(tbuf, sizeof(tbuf), " %b %d,%Y %T", tm); 310 311 if ((skey.val = (char *)malloc(16 + 1)) == NULL) 312 err(1, "Can't allocate memory"); 313 314 /* Zero out old key if necessary (entry would change size) */ 315 if (zerokey) { 316 (void)skeyzero(&skey, pp->pw_name); 317 /* Re-open keys file and seek to the end */ 318 if (skeylookup(&skey, pp->pw_name) == -1) 319 err(1, "cannot open database"); 320 } 321 322 btoa8(skey.val, key); 323 324 /* 325 * Obtain an exclusive lock on the key file so we don't 326 * clobber someone authenticating themselves at the same time. 327 */ 328 for (i = 0; i < 300; i++) { 329 if ((rval = flock(fileno(skey.keyfile), LOCK_EX|LOCK_NB)) == 0 330 || errno != EWOULDBLOCK) 331 break; 332 usleep(100000); /* Sleep for 0.1 seconds */ 333 } 334 if (rval == -1) { /* Can't get exclusive lock */ 335 errno = EAGAIN; 336 err(1, "cannot open database"); 337 } 338 339 /* Don't save algorithm type for md4 (keep record length same) */ 340 if (strcmp(skey_get_algorithm(), "md4") == 0) 341 (void)fprintf(skey.keyfile, "%s %04d %-16s %s %-21s\n", 342 pp->pw_name, n, seed, skey.val, tbuf); 343 else 344 (void)fprintf(skey.keyfile, "%s %s %04d %-16s %s %-21s\n", 345 pp->pw_name, skey_get_algorithm(), n, seed, skey.val, tbuf); 346 347 (void)fclose(skey.keyfile); 348 349 (void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name, 350 skey_get_algorithm(), n, seed); 351 (void)printf("Next login password: %s\n\n", 352 hexmode ? put8(buf, key) : btoe(buf, key)); 353 354 return(0); 355 } 356