Annotation of src/usr.bin/skeyinit/skeyinit.c, Revision 1.41
1.41 ! millert 1: /* $OpenBSD: skeyinit.c,v 1.40 2002/06/23 03:07:22 deraadt Exp $ */
1.1 deraadt 2:
1.28 millert 3: /* OpenBSD S/Key (skeyinit.c)
1.1 deraadt 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>
1.20 millert 10: * Todd C. Miller <Todd.Miller@courtesan.com>
11: *
1.28 millert 12: * S/Key initialization and seed update
1.1 deraadt 13: */
14:
15: #include <sys/param.h>
1.20 millert 16: #include <sys/file.h>
1.32 millert 17: #include <sys/resource.h>
18: #include <sys/stat.h>
1.1 deraadt 19: #include <sys/time.h>
20:
1.32 millert 21: #include <ctype.h>
1.19 millert 22: #include <err.h>
1.20 millert 23: #include <errno.h>
1.19 millert 24: #include <pwd.h>
1.28 millert 25: #include <readpassphrase.h>
1.1 deraadt 26: #include <stdio.h>
27: #include <stdlib.h>
28: #include <string.h>
1.19 millert 29: #include <syslog.h>
30: #include <time.h>
1.1 deraadt 31: #include <unistd.h>
1.6 millert 32: #include <utmp.h>
1.19 millert 33:
1.4 millert 34: #include <skey.h>
1.32 millert 35: #include <bsd_auth.h>
1.1 deraadt 36:
1.4 millert 37: #ifndef SKEY_NAMELEN
1.17 millert 38: #define SKEY_NAMELEN 4
1.4 millert 39: #endif
1.1 deraadt 40:
1.36 millert 41: void usage(void);
1.38 millert 42: void secure_mode(int *, char *, char *, char *, size_t);
43: void normal_mode(char *, int, char *, char *);
1.31 millert 44: void timedout(int);
1.32 millert 45: void convert_db(void);
46: void enable_db(int);
1.8 millert 47:
1.1 deraadt 48: int
1.36 millert 49: main(int argc, char **argv)
1.1 deraadt 50: {
1.35 millert 51: int rval, i, l, n, defaultsetup, rmkey, hexmode, enable, convert;
1.1 deraadt 52: char hostname[MAXHOSTNAMELEN];
1.38 millert 53: char seed[SKEY_MAX_SEED_LEN + 1];
1.32 millert 54: char buf[256], key[SKEY_BINKEY_SIZE], filename[PATH_MAX], *ht;
55: char lastc, me[UT_NAMESIZE + 1], *p, *auth_type;
1.39 millert 56: u_int32_t noise;
1.1 deraadt 57: struct skey skey;
58: struct passwd *pp;
59:
1.35 millert 60: n = rmkey = hexmode = enable = convert = 0;
1.32 millert 61: defaultsetup = 1;
62: ht = auth_type = NULL;
1.4 millert 63:
1.39 millert 64: /* Build up a default seed based on the hostname and some noise */
1.1 deraadt 65: if (gethostname(hostname, sizeof(hostname)) < 0)
66: err(1, "gethostname");
1.38 millert 67: for (i = 0, p = seed; hostname[i] && i < SKEY_NAMELEN; i++) {
1.25 millert 68: if (isalpha(hostname[i])) {
1.26 millert 69: if (isupper(hostname[i]))
70: hostname[i] = tolower(hostname[i]);
71: *p++ = hostname[i];
1.25 millert 72: } else if (isdigit(hostname[i]))
73: *p++ = hostname[i];
1.39 millert 74: }
75: noise = arc4random();
76: for (i = 0; i < 5; i++) {
77: *p++ = (noise % 10) + '0';
78: noise /= 10;
1.25 millert 79: }
80: *p = '\0';
1.1 deraadt 81:
82: if ((pp = getpwuid(getuid())) == NULL)
1.40 deraadt 83: err(1, "no user with uid %u", getuid());
1.4 millert 84: (void)strcpy(me, pp->pw_name);
1.1 deraadt 85:
86: if ((pp = getpwnam(me)) == NULL)
87: err(1, "Who are you?");
88:
1.8 millert 89: for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
90: if (argv[i][2] == '\0') {
91: /* Single character switch */
92: switch (argv[i][1]) {
1.32 millert 93: case 'a':
94: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 95: usage();
1.41 ! millert 96: if (auth_type == NULL)
! 97: auth_type = argv[i];
1.32 millert 98: break;
1.4 millert 99: case 's':
100: defaultsetup = 0;
1.32 millert 101: auth_type = "skey";
1.4 millert 102: break;
103: case 'x':
104: hexmode = 1;
105: break;
1.35 millert 106: case 'r':
107: rmkey = 1;
1.4 millert 108: break;
1.17 millert 109: case 'n':
1.23 deraadt 110: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 111: usage();
1.17 millert 112: if ((n = atoi(argv[i])) < 1 || n >= SKEY_MAX_SEQ)
113: errx(1, "count must be > 0 and < %d",
114: SKEY_MAX_SEQ);
115: break;
1.32 millert 116: case 'C':
117: convert = 1;
118: break;
119: case 'D':
120: enable = -1;
121: break;
122: case 'E':
123: enable = 1;
124: break;
1.8 millert 125: default:
1.36 millert 126: usage();
1.8 millert 127: }
128: } else {
129: /* Multi character switches are hash types */
130: if ((ht = skey_set_algorithm(&argv[i][1])) == NULL) {
131: warnx("Unknown hash algorithm %s", &argv[i][1]);
1.36 millert 132: usage();
1.8 millert 133: }
1.7 millert 134: }
1.8 millert 135: i++;
1.7 millert 136: }
1.32 millert 137: argv += i;
138: argc -= i;
1.7 millert 139:
1.32 millert 140: if (argc > 1 || (enable && convert) || (enable && argc) ||
141: (convert && argc))
1.36 millert 142: usage();
1.32 millert 143:
144: /* Handle -C, -D, and -E */
1.34 millert 145: if (convert || enable) {
146: if (convert)
147: convert_db();
148: else
149: enable_db(enable);
150: exit(0);
151: }
1.32 millert 152:
153: /* Check for optional user string. */
154: if (argc == 1) {
1.36 millert 155: if ((pp = getpwnam(argv[0])) == NULL) {
1.16 millert 156: if (getuid() == 0) {
157: static struct passwd _pp;
158:
1.36 millert 159: _pp.pw_name = argv[0];
1.16 millert 160: pp = &_pp;
1.36 millert 161: warnx("Warning, user unknown: %s", argv[0]);
1.16 millert 162: } else {
1.36 millert 163: errx(1, "User unknown: %s", argv[0]);
1.16 millert 164: }
1.32 millert 165: } else if (strcmp(pp->pw_name, me) != 0 && getuid() != 0) {
166: /* Only root can change other's S/Keys. */
167: errx(1, "Permission denied.");
1.1 deraadt 168: }
169: }
170:
1.41 ! millert 171: switch (skey_haskey(pp->pw_name)) {
! 172: case -1:
! 173: if (errno == ENOENT || errno == EPERM)
! 174: errx(1, "S/Key disabled");
! 175: else
! 176: err(1, "cannot open database");
! 177: break;
! 178: case 0:
! 179: /* existing user */
! 180: break;
! 181: case 1:
! 182: if (!defaultsetup) {
! 183: fprintf(stderr,
! 184: "You must authenticate yourself before using S/Key for the first time. In
! 185: secure mode this is normally done via an existing S/Key key. However, since
! 186: you do not have an entry in the S/Key database you will have to specify an
! 187: alternate authentication type via the `-a' flag, e.g.
! 188: \"skeyinit -s -a krb5\" or \"skeyinit -s -a passwd\"\n
! 189: Note that entering a plaintext password over a non-secure link defeats the
! 190: purpose of using S/Key in the fist place.\n");
! 191: exit(1);
! 192: }
! 193: break;
! 194: }
! 195:
1.28 millert 196: if (defaultsetup)
1.32 millert 197: fputs("Reminder - Only use this method if you are directly "
198: "connected\n or have an encrypted channel. If "
199: "you are using telnet,\n hit return now and use "
200: "skeyinit -s.\n", stderr);
1.28 millert 201:
1.1 deraadt 202: if (getuid() != 0) {
1.32 millert 203: if ((pp = pw_dup(pp)) == NULL)
204: err(1, NULL);
205: if (!auth_userokay(pp->pw_name, auth_type, NULL, NULL))
206: errx(1, "Password incorrect");
1.10 millert 207: }
1.1 deraadt 208:
1.28 millert 209: /*
210: * Lookup and lock the record we are about to modify.
211: * If this is a new entry this will prevent other users
212: * from appending new entries (and clobbering ours).
213: */
1.1 deraadt 214: rval = skeylookup(&skey, pp->pw_name);
215: switch (rval) {
1.4 millert 216: case -1:
1.41 ! millert 217: err(1, "cannot open database");
1.21 millert 218: break;
1.4 millert 219: case 0:
1.35 millert 220: /* remove user if asked to do so */
221: if (rmkey) {
222: if (snprintf(filename, sizeof(filename),
223: "%s/%s", _PATH_SKEYDIR, pp->pw_name)
224: >= sizeof(filename)) {
225: errno = ENAMETOOLONG;
226: err(1, "Cannot remove S/Key entry");
227: }
228: if (unlink(filename) != 0)
229: err(1, "Cannot remove S/Key entry");
230: printf("S/Key entry for %s removed.\n",
231: pp->pw_name);
232: exit(0);
233: }
1.4 millert 234:
1.28 millert 235: (void)printf("[Updating %s with %s]\n", pp->pw_name,
236: ht ? ht : skey_get_algorithm());
237: (void)printf("Old seed: [%s] %s\n",
238: skey_get_algorithm(), skey.seed);
1.4 millert 239:
240: /*
1.25 millert 241: * Sanity check old seed.
242: */
243: l = strlen(skey.seed);
244: for (p = skey.seed; *p; p++) {
245: if (isalpha(*p)) {
246: if (isupper(*p))
247: *p = tolower(*p);
248: } else if (!isdigit(*p)) {
249: memmove(p, p + 1, l - (p - skey.seed));
250: l--;
251: }
252: }
253:
1.28 millert 254: /* If the seed ends in 0-8 just add one. */
1.4 millert 255: if (l > 0) {
256: lastc = skey.seed[l - 1];
257: if (isdigit(lastc) && lastc != '9') {
1.38 millert 258: (void)strcpy(seed, skey.seed);
259: seed[l - 1] = lastc + 1;
1.4 millert 260: }
261: if (isdigit(lastc) && lastc == '9' && l < 16) {
1.38 millert 262: (void)strcpy(seed, skey.seed);
263: seed[l - 1] = '0';
264: seed[l] = '0';
265: seed[l + 1] = '\0';
1.4 millert 266: }
1.1 deraadt 267: }
1.4 millert 268: break;
269: case 1:
1.35 millert 270: if (rmkey)
271: errx(1, "You have no entry to remove.");
1.28 millert 272: (void)printf("[Adding %s with %s]\n", pp->pw_name,
273: ht ? ht : skey_get_algorithm());
1.32 millert 274: if (snprintf(filename, sizeof(filename), "%s/%s",
275: _PATH_SKEYDIR, pp->pw_name) >= sizeof(filename)) {
276: errno = ENAMETOOLONG;
277: err(1, "Cannot create S/Key entry");
278: }
1.36 millert 279: if ((l = open(filename,
280: O_RDWR | O_NONBLOCK | O_CREAT | O_TRUNC |O_NOFOLLOW,
1.32 millert 281: S_IRUSR | S_IWUSR)) == -1 ||
282: flock(l, LOCK_EX) != 0 ||
283: (skey.keyfile = fdopen(l, "r+")) == NULL)
284: err(1, "Cannot create S/Key entry");
1.4 millert 285: break;
1.1 deraadt 286: }
1.32 millert 287: if (fchown(fileno(skey.keyfile), pp->pw_uid, -1) != 0 ||
288: fchmod(fileno(skey.keyfile), S_IRUSR | S_IWUSR) != 0)
289: err(1, "can't set owner/mode for %s", pp->pw_name);
1.17 millert 290: if (n == 0)
291: n = 99;
1.1 deraadt 292:
1.8 millert 293: /* Set hash type if asked to */
1.28 millert 294: if (ht && strcmp(ht, skey_get_algorithm()) != 0)
295: skey_set_algorithm(ht);
296:
297: alarm(180);
298: if (!defaultsetup)
1.38 millert 299: secure_mode(&n, key, seed, buf, sizeof(buf));
1.28 millert 300: else
1.38 millert 301: normal_mode(pp->pw_name, n, key, seed);
1.28 millert 302: alarm(0);
1.4 millert 303:
1.32 millert 304: /* XXX - why use malloc here? */
1.28 millert 305: if ((skey.val = (char *)malloc(16 + 1)) == NULL)
306: err(1, "Can't allocate memory");
307: btoa8(skey.val, key);
1.1 deraadt 308:
1.32 millert 309: (void)fseek(skey.keyfile, 0L, SEEK_SET);
310: (void)fprintf(skey.keyfile, "%s\n%s\n%04d\n%s\n%s\n",
311: pp->pw_name, skey_get_algorithm(), n, seed, skey.val);
1.28 millert 312: (void)fclose(skey.keyfile);
1.4 millert 313:
1.28 millert 314: (void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name,
1.38 millert 315: skey_get_algorithm(), n, seed);
1.28 millert 316: (void)printf("Next login password: %s\n\n",
317: hexmode ? put8(buf, key) : btoe(buf, key));
318: exit(0);
319: }
1.1 deraadt 320:
1.28 millert 321: void
1.38 millert 322: secure_mode(int *count, char *key, char *seed, char *buf, size_t bufsiz)
1.28 millert 323: {
1.38 millert 324: char *p, newseed[SKEY_MAX_SEED_LEN + 2];
1.28 millert 325: int i, n;
1.4 millert 326:
1.28 millert 327: (void)puts("You need the 6 words generated from the \"skey\" command.");
328: for (i = 0; ; i++) {
329: if (i >= 2)
330: exit(1);
331:
332: (void)printf("Enter sequence count from 1 to %d: ",
333: SKEY_MAX_SEQ);
334: (void)fgets(buf, bufsiz, stdin);
335: clearerr(stdin);
336: n = atoi(buf);
337: if (n > 0 && n < SKEY_MAX_SEQ)
338: break; /* Valid range */
339: (void)fprintf(stderr, "ERROR: Count must be between 1 and %d\n",
340: SKEY_MAX_SEQ);
341: }
1.1 deraadt 342:
1.28 millert 343: for (i = 0; ; i++) {
344: if (i >= 2)
345: exit(1);
346:
1.38 millert 347: (void)printf("Enter new seed [default %s]: ", seed);
348: (void)fgets(newseed, sizeof(newseed), stdin); /* XXX */
1.28 millert 349: clearerr(stdin);
1.38 millert 350: rip(newseed);
351: if (strlen(newseed) > SKEY_MAX_SEED_LEN) {
1.28 millert 352: (void)fprintf(stderr, "ERROR: Seed must be between 1 "
353: "and %d characters in length\n", SKEY_MAX_SEED_LEN);
354: continue;
355: }
1.38 millert 356: for (p = newseed; *p; p++) {
1.28 millert 357: if (isspace(*p)) {
358: (void)fputs("ERROR: Seed must not contain "
359: "any spaces\n", stderr);
1.1 deraadt 360: break;
1.28 millert 361: } else if (isalpha(*p)) {
362: if (isupper(*p))
363: *p = tolower(*p);
364: } else if (!isdigit(*p)) {
365: (void)fputs("ERROR: Seed must be purely "
366: "alphanumeric\n", stderr);
367: break;
368: }
1.1 deraadt 369: }
1.28 millert 370: if (*p == '\0')
371: break; /* Valid seed */
372: }
1.38 millert 373: if (newseed[0] != '\0')
374: (void)strcpy(seed, newseed);
1.1 deraadt 375:
1.28 millert 376: for (i = 0; ; i++) {
377: if (i >= 2)
378: exit(1);
379:
380: (void)printf("otp-%s %d %s\nS/Key access password: ",
381: skey_get_algorithm(), n, seed);
382: (void)fgets(buf, bufsiz, stdin);
383: clearerr(stdin);
384: rip(buf);
385: backspace(buf);
386:
387: if (buf[0] == '?') {
388: (void)puts("Enter 6 words from secure S/Key calculation.");
389: continue;
390: } else if (buf[0] == '\0')
391: exit(1);
392:
393: if (etob(key, buf) == 1 || atob8(key, buf) == 0)
394: break; /* Valid format */
395: (void)fputs("ERROR: Invalid format - try again with the 6 words.\n",
396: stderr);
1.1 deraadt 397: }
1.28 millert 398: *count= n;
399: }
1.1 deraadt 400:
1.28 millert 401: void
1.38 millert 402: normal_mode(char *username, int n, char *key, char *seed)
1.28 millert 403: {
404: int i, nn;
1.38 millert 405: char passwd[SKEY_MAX_PW_LEN+2], key2[SKEY_BINKEY_SIZE];
1.1 deraadt 406:
1.28 millert 407: /* Get user's secret passphrase */
408: for (i = 0; ; i++) {
409: if (i > 2)
1.38 millert 410: errx(1, "S/Key entry not updated");
1.28 millert 411:
412: if (readpassphrase("Enter secret passphrase: ", passwd,
413: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
414: exit(1);
415:
416: if (strlen(passwd) < SKEY_MIN_PW_LEN) {
417: (void)fprintf(stderr,
418: "ERROR: Your passphrase must be at least %d "
419: "characters long.\n", SKEY_MIN_PW_LEN);
420: continue;
421: } else if (strcmp(passwd, username) == 0) {
422: (void)fputs("ERROR: Your passphrase may not be the "
423: "same as your user name.\n", stderr);
424: continue;
425: } else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") ==
426: strlen(passwd)) {
427: (void)fputs("ERROR: Your passphrase must contain more "
428: "than just lower case letters.\nWhitespace, "
1.37 aaron 429: "numbers, and punctuation are suggested.\n",
430: stderr);
1.28 millert 431: continue;
432: } else if (strlen(passwd) > 63) {
433: (void)fprintf(stderr, "WARNING: Your passphrase is "
434: "longer than the recommended maximum length of 63\n");
435: }
436: /* XXX - should check for passphrase that is really too long */
1.13 millert 437:
1.38 millert 438: /* Crunch seed and passphrase into starting key */
439: nn = keycrunch(key, seed, passwd);
440: memset(passwd, 0, sizeof(passwd));
441: if (nn != 0)
442: err(2, "key crunch failed");
443:
444: if (readpassphrase("Again secret passphrase: ", passwd,
445: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
446: exit(1);
447:
448: /* Crunch seed and passphrase into starting key */
449: nn = keycrunch(key2, seed, passwd);
450: memset(passwd, 0, sizeof(passwd));
451: if (nn != 0)
452: err(2, "key crunch failed");
453:
454: if (memcmp(key, key2, sizeof(key2)) == 0)
1.28 millert 455: break;
1.1 deraadt 456:
1.28 millert 457: (void)fputs("Passphrases do not match.\n", stderr);
1.20 millert 458: }
1.28 millert 459:
460: nn = n;
461: while (nn-- != 0)
462: f(key);
463: }
464:
1.32 millert 465: void
1.36 millert 466: enable_db(int op)
1.32 millert 467: {
468: if (op == 1) {
469: /* enable */
470: if (mkdir(_PATH_SKEYDIR, 01730) != 0 && errno != EEXIST)
471: err(1, "can't mkdir %s", _PATH_SKEYDIR);
1.33 millert 472: if (chown(_PATH_SKEYDIR, geteuid(), getegid()) != 0)
473: err(1, "can't chown %s", _PATH_SKEYDIR);
1.32 millert 474: if (chmod(_PATH_SKEYDIR, 01730) != 0)
475: err(1, "can't chmod %s", _PATH_SKEYDIR);
476: } else {
477: /* disable */
478: if (chmod(_PATH_SKEYDIR, 0) != 0 && errno != ENOENT)
479: err(1, "can't chmod %s", _PATH_SKEYDIR);
480: }
481: }
482:
483: #define _PATH_SKEYKEYS "/etc/skeykeys"
484: void
485: convert_db(void)
486: {
487: struct passwd *pp;
488: uid_t uid;
489: FILE *keyfile;
490: FILE *newfile;
491: char buf[256], *logname, *hashtype, *seed, *val, *cp;
492: char filename[PATH_MAX];
493: int fd, n;
494:
495: if ((keyfile = fopen(_PATH_SKEYKEYS, "r")) == NULL)
496: err(1, "can't open %s", _PATH_SKEYKEYS);
497: if (flock(fileno(keyfile), LOCK_EX) != 0)
498: err(1, "can't lock %s", _PATH_SKEYKEYS);
1.34 millert 499: enable_db(1);
1.32 millert 500:
501: /*
502: * Loop over each entry in _PATH_SKEYKEYS, creating a file
503: * in _PATH_SKEYDIR for each one.
504: */
505: while (fgets(buf, sizeof(buf), keyfile) != NULL) {
506: if (buf[0] == '#')
507: continue;
508: if ((logname = strtok(buf, " \t")) == NULL)
509: continue;
510: if ((cp = strtok(NULL, " \t")) == NULL)
511: continue;
512: if (isalpha(*cp)) {
513: hashtype = cp;
514: if ((cp = strtok(NULL, " \t")) == NULL)
515: continue;
516: } else
517: hashtype = "md4";
518: n = atoi(cp);
519: if ((seed = strtok(NULL, " \t")) == NULL)
520: continue;
521: if ((val = strtok(NULL, " \t")) == NULL)
522: continue;
523:
524: if ((pp = getpwnam(logname)) != NULL)
525: uid = pp->pw_uid;
526: else
527: uid = 0;
528:
529: /* Now write the new-style record. */
530: if (snprintf(filename, sizeof(filename), "%s/%s", _PATH_SKEYDIR,
531: logname) >= sizeof(filename)) {
532: errno = ENAMETOOLONG;
533: warn("%s", logname);
534: continue;
535: }
536: fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
537: if (fd == -1 || flock(fd, LOCK_EX) != 0 ||
538: (newfile = fdopen(fd, "r+")) == NULL) {
539: warn("%s", logname);
540: continue;
541: }
542: (void)fprintf(newfile, "%s\n%s\n%04d\n%s\n%s\n", logname,
543: hashtype, n, seed, val);
544: (void)fchown(fileno(newfile), uid, -1);
545: (void)fclose(newfile);
546: }
547: printf("%s has been populated. NOTE: %s has *not* been removed.\n"
548: "It should be removed once you have verified that the new keys "
549: "work.\n", _PATH_SKEYDIR, _PATH_SKEYKEYS);
550: }
551:
1.28 millert 552: #define TIMEOUT_MSG "Timed out waiting for input.\n"
553: void
1.36 millert 554: timedout(int signo)
1.28 millert 555: {
1.10 millert 556:
1.28 millert 557: write(STDERR_FILENO, TIMEOUT_MSG, sizeof(TIMEOUT_MSG) - 1);
558: _exit(1);
1.8 millert 559: }
560:
561: void
1.36 millert 562: usage(void)
1.8 millert 563: {
1.36 millert 564: extern char *__progname;
565:
566: (void)fprintf(stderr, "usage: %s [-r] [-s] [-x] [-C] [-D] [-E] "
1.32 millert 567: "[-a auth_type] [-n count]\n "
1.36 millert 568: "[-md4|-md5|-sha1|-rmd160] [user]\n", __progname);
1.8 millert 569: exit(1);
1.1 deraadt 570: }
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