Annotation of src/usr.bin/skeyinit/skeyinit.c, Revision 1.50
1.50 ! deraadt 1: /* $OpenBSD: skeyinit.c,v 1.49 2004/09/14 22:58:57 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);
1.44 deraadt 42: void secure_mode(int *, char *, char *, size_t, char *, size_t);
1.38 millert 43: void normal_mode(char *, int, char *, char *);
1.32 millert 44: void convert_db(void);
45: void enable_db(int);
1.8 millert 46:
1.1 deraadt 47: int
1.36 millert 48: main(int argc, char **argv)
1.1 deraadt 49: {
1.35 millert 50: int rval, i, l, n, defaultsetup, rmkey, hexmode, enable, convert;
1.1 deraadt 51: char hostname[MAXHOSTNAMELEN];
1.38 millert 52: char seed[SKEY_MAX_SEED_LEN + 1];
1.32 millert 53: char buf[256], key[SKEY_BINKEY_SIZE], filename[PATH_MAX], *ht;
54: char lastc, me[UT_NAMESIZE + 1], *p, *auth_type;
1.39 millert 55: u_int32_t noise;
1.1 deraadt 56: struct skey skey;
57: struct passwd *pp;
58:
1.35 millert 59: n = rmkey = hexmode = enable = convert = 0;
1.32 millert 60: defaultsetup = 1;
61: ht = auth_type = NULL;
1.4 millert 62:
1.39 millert 63: /* Build up a default seed based on the hostname and some noise */
1.1 deraadt 64: if (gethostname(hostname, sizeof(hostname)) < 0)
65: err(1, "gethostname");
1.38 millert 66: for (i = 0, p = seed; hostname[i] && i < SKEY_NAMELEN; i++) {
1.25 millert 67: if (isalpha(hostname[i])) {
1.26 millert 68: if (isupper(hostname[i]))
69: hostname[i] = tolower(hostname[i]);
70: *p++ = hostname[i];
1.25 millert 71: } else if (isdigit(hostname[i]))
72: *p++ = hostname[i];
1.39 millert 73: }
74: noise = arc4random();
75: for (i = 0; i < 5; i++) {
76: *p++ = (noise % 10) + '0';
77: noise /= 10;
1.25 millert 78: }
79: *p = '\0';
1.1 deraadt 80:
81: if ((pp = getpwuid(getuid())) == NULL)
1.40 deraadt 82: err(1, "no user with uid %u", getuid());
1.42 deraadt 83: (void)strlcpy(me, pp->pw_name, sizeof me);
1.1 deraadt 84:
85: if ((pp = getpwnam(me)) == NULL)
86: err(1, "Who are you?");
87:
1.8 millert 88: for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
89: if (argv[i][2] == '\0') {
90: /* Single character switch */
91: switch (argv[i][1]) {
1.32 millert 92: case 'a':
93: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 94: usage();
1.48 otto 95: auth_type = argv[i];
1.32 millert 96: break;
1.4 millert 97: case 's':
98: defaultsetup = 0;
1.48 otto 99: if (auth_type == NULL)
100: auth_type = "skey";
1.4 millert 101: break;
102: case 'x':
103: hexmode = 1;
104: break;
1.35 millert 105: case 'r':
106: rmkey = 1;
1.4 millert 107: break;
1.17 millert 108: case 'n':
1.23 deraadt 109: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 110: usage();
1.17 millert 111: if ((n = atoi(argv[i])) < 1 || n >= SKEY_MAX_SEQ)
112: errx(1, "count must be > 0 and < %d",
113: SKEY_MAX_SEQ);
114: break;
1.32 millert 115: case 'C':
116: convert = 1;
117: break;
118: case 'D':
119: enable = -1;
120: break;
121: case 'E':
122: enable = 1;
123: break;
1.8 millert 124: default:
1.36 millert 125: usage();
1.8 millert 126: }
127: } else {
128: /* Multi character switches are hash types */
129: if ((ht = skey_set_algorithm(&argv[i][1])) == NULL) {
130: warnx("Unknown hash algorithm %s", &argv[i][1]);
1.36 millert 131: usage();
1.8 millert 132: }
1.7 millert 133: }
1.8 millert 134: i++;
1.7 millert 135: }
1.32 millert 136: argv += i;
137: argc -= i;
1.7 millert 138:
1.32 millert 139: if (argc > 1 || (enable && convert) || (enable && argc) ||
140: (convert && argc))
1.36 millert 141: usage();
1.32 millert 142:
143: /* Handle -C, -D, and -E */
1.34 millert 144: if (convert || enable) {
145: if (convert)
146: convert_db();
147: else
148: enable_db(enable);
149: exit(0);
150: }
1.32 millert 151:
152: /* Check for optional user string. */
153: if (argc == 1) {
1.36 millert 154: if ((pp = getpwnam(argv[0])) == NULL) {
1.16 millert 155: if (getuid() == 0) {
156: static struct passwd _pp;
157:
1.36 millert 158: _pp.pw_name = argv[0];
1.16 millert 159: pp = &_pp;
1.36 millert 160: warnx("Warning, user unknown: %s", argv[0]);
1.16 millert 161: } else {
1.36 millert 162: errx(1, "User unknown: %s", argv[0]);
1.16 millert 163: }
1.32 millert 164: } else if (strcmp(pp->pw_name, me) != 0 && getuid() != 0) {
165: /* Only root can change other's S/Keys. */
166: errx(1, "Permission denied.");
1.1 deraadt 167: }
168: }
169:
1.41 millert 170: switch (skey_haskey(pp->pw_name)) {
171: case -1:
172: if (errno == ENOENT || errno == EPERM)
173: errx(1, "S/Key disabled");
174: else
175: err(1, "cannot open database");
176: break;
177: case 0:
178: /* existing user */
179: break;
180: case 1:
1.48 otto 181: if (!defaultsetup && strcmp(auth_type, "skey") == 0) {
1.41 millert 182: fprintf(stderr,
1.45 espie 183: "You must authenticate yourself before using S/Key for the first time. In\n"
184: "secure mode this is normally done via an existing S/Key key. However, since\n"
185: "you do not have an entry in the S/Key database you will have to specify an\n"
186: "alternate authentication type via the `-a' flag, e.g.\n"
187: " \"skeyinit -s -a krb5\" or \"skeyinit -s -a passwd\"\n\n"
188: "Note that entering a plaintext password over a non-secure link defeats the\n"
189: "purpose of using S/Key in the fist place.\n");
1.41 millert 190: exit(1);
191: }
192: break;
193: }
194:
1.28 millert 195: if (defaultsetup)
1.32 millert 196: fputs("Reminder - Only use this method if you are directly "
197: "connected\n or have an encrypted channel. If "
198: "you are using telnet,\n hit return now and use "
199: "skeyinit -s.\n", stderr);
1.28 millert 200:
1.1 deraadt 201: if (getuid() != 0) {
1.32 millert 202: if ((pp = pw_dup(pp)) == NULL)
203: err(1, NULL);
204: if (!auth_userokay(pp->pw_name, auth_type, NULL, NULL))
205: errx(1, "Password incorrect");
1.10 millert 206: }
1.1 deraadt 207:
1.28 millert 208: /*
209: * Lookup and lock the record we are about to modify.
210: * If this is a new entry this will prevent other users
211: * from appending new entries (and clobbering ours).
212: */
1.1 deraadt 213: rval = skeylookup(&skey, pp->pw_name);
214: switch (rval) {
1.4 millert 215: case -1:
1.41 millert 216: err(1, "cannot open database");
1.21 millert 217: break;
1.4 millert 218: case 0:
1.35 millert 219: /* remove user if asked to do so */
220: if (rmkey) {
221: if (snprintf(filename, sizeof(filename),
222: "%s/%s", _PATH_SKEYDIR, pp->pw_name)
223: >= sizeof(filename)) {
224: errno = ENAMETOOLONG;
225: err(1, "Cannot remove S/Key entry");
226: }
227: if (unlink(filename) != 0)
228: err(1, "Cannot remove S/Key entry");
229: printf("S/Key entry for %s removed.\n",
230: pp->pw_name);
231: exit(0);
232: }
1.4 millert 233:
1.28 millert 234: (void)printf("[Updating %s with %s]\n", pp->pw_name,
235: ht ? ht : skey_get_algorithm());
236: (void)printf("Old seed: [%s] %s\n",
237: skey_get_algorithm(), skey.seed);
1.4 millert 238:
239: /*
1.25 millert 240: * Sanity check old seed.
241: */
242: l = strlen(skey.seed);
243: for (p = skey.seed; *p; p++) {
244: if (isalpha(*p)) {
245: if (isupper(*p))
246: *p = tolower(*p);
247: } else if (!isdigit(*p)) {
248: memmove(p, p + 1, l - (p - skey.seed));
249: l--;
250: }
251: }
252:
1.28 millert 253: /* If the seed ends in 0-8 just add one. */
1.4 millert 254: if (l > 0) {
255: lastc = skey.seed[l - 1];
256: if (isdigit(lastc) && lastc != '9') {
1.43 deraadt 257: (void)strlcpy(seed, skey.seed,
258: sizeof seed);
1.38 millert 259: seed[l - 1] = lastc + 1;
1.4 millert 260: }
261: if (isdigit(lastc) && lastc == '9' && l < 16) {
1.43 deraadt 262: (void)strlcpy(seed, skey.seed,
263: sizeof seed);
1.38 millert 264: seed[l - 1] = '0';
265: seed[l] = '0';
266: seed[l + 1] = '\0';
1.4 millert 267: }
1.1 deraadt 268: }
1.4 millert 269: break;
270: case 1:
1.35 millert 271: if (rmkey)
272: errx(1, "You have no entry to remove.");
1.28 millert 273: (void)printf("[Adding %s with %s]\n", pp->pw_name,
274: ht ? ht : skey_get_algorithm());
1.32 millert 275: if (snprintf(filename, sizeof(filename), "%s/%s",
276: _PATH_SKEYDIR, pp->pw_name) >= sizeof(filename)) {
277: errno = ENAMETOOLONG;
278: err(1, "Cannot create S/Key entry");
279: }
1.36 millert 280: if ((l = open(filename,
281: O_RDWR | O_NONBLOCK | O_CREAT | O_TRUNC |O_NOFOLLOW,
1.32 millert 282: S_IRUSR | S_IWUSR)) == -1 ||
283: flock(l, LOCK_EX) != 0 ||
284: (skey.keyfile = fdopen(l, "r+")) == NULL)
285: err(1, "Cannot create S/Key entry");
1.4 millert 286: break;
1.1 deraadt 287: }
1.32 millert 288: if (fchown(fileno(skey.keyfile), pp->pw_uid, -1) != 0 ||
289: fchmod(fileno(skey.keyfile), S_IRUSR | S_IWUSR) != 0)
290: err(1, "can't set owner/mode for %s", pp->pw_name);
1.17 millert 291: if (n == 0)
1.47 otto 292: n = 100;
1.1 deraadt 293:
1.8 millert 294: /* Set hash type if asked to */
1.28 millert 295: if (ht && strcmp(ht, skey_get_algorithm()) != 0)
296: skey_set_algorithm(ht);
297:
298: alarm(180);
299: if (!defaultsetup)
1.44 deraadt 300: secure_mode(&n, key, seed, sizeof seed, buf, sizeof(buf));
1.28 millert 301: else
1.38 millert 302: normal_mode(pp->pw_name, n, key, seed);
1.28 millert 303: alarm(0);
1.4 millert 304:
1.32 millert 305: /* XXX - why use malloc here? */
1.28 millert 306: if ((skey.val = (char *)malloc(16 + 1)) == NULL)
307: err(1, "Can't allocate memory");
308: btoa8(skey.val, key);
1.1 deraadt 309:
1.32 millert 310: (void)fseek(skey.keyfile, 0L, SEEK_SET);
311: (void)fprintf(skey.keyfile, "%s\n%s\n%04d\n%s\n%s\n",
312: pp->pw_name, skey_get_algorithm(), n, seed, skey.val);
1.28 millert 313: (void)fclose(skey.keyfile);
1.4 millert 314:
1.28 millert 315: (void)printf("\nID %s skey is otp-%s %d %s\n", pp->pw_name,
1.38 millert 316: skey_get_algorithm(), n, seed);
1.28 millert 317: (void)printf("Next login password: %s\n\n",
318: hexmode ? put8(buf, key) : btoe(buf, key));
319: exit(0);
320: }
1.1 deraadt 321:
1.28 millert 322: void
1.44 deraadt 323: secure_mode(int *count, char *key, char *seed, size_t seedlen,
324: char *buf, size_t bufsiz)
1.28 millert 325: {
1.38 millert 326: char *p, newseed[SKEY_MAX_SEED_LEN + 2];
1.28 millert 327: int i, n;
1.4 millert 328:
1.28 millert 329: (void)puts("You need the 6 words generated from the \"skey\" command.");
330: for (i = 0; ; i++) {
331: if (i >= 2)
332: exit(1);
333:
334: (void)printf("Enter sequence count from 1 to %d: ",
335: SKEY_MAX_SEQ);
336: (void)fgets(buf, bufsiz, stdin);
337: clearerr(stdin);
338: n = atoi(buf);
339: if (n > 0 && n < SKEY_MAX_SEQ)
340: break; /* Valid range */
341: (void)fprintf(stderr, "ERROR: Count must be between 1 and %d\n",
342: SKEY_MAX_SEQ);
343: }
1.1 deraadt 344:
1.28 millert 345: for (i = 0; ; i++) {
346: if (i >= 2)
347: exit(1);
348:
1.38 millert 349: (void)printf("Enter new seed [default %s]: ", seed);
350: (void)fgets(newseed, sizeof(newseed), stdin); /* XXX */
1.28 millert 351: clearerr(stdin);
1.38 millert 352: rip(newseed);
353: if (strlen(newseed) > SKEY_MAX_SEED_LEN) {
1.28 millert 354: (void)fprintf(stderr, "ERROR: Seed must be between 1 "
355: "and %d characters in length\n", SKEY_MAX_SEED_LEN);
356: continue;
357: }
1.38 millert 358: for (p = newseed; *p; p++) {
1.28 millert 359: if (isspace(*p)) {
360: (void)fputs("ERROR: Seed must not contain "
361: "any spaces\n", stderr);
1.1 deraadt 362: break;
1.28 millert 363: } else if (isalpha(*p)) {
364: if (isupper(*p))
365: *p = tolower(*p);
366: } else if (!isdigit(*p)) {
367: (void)fputs("ERROR: Seed must be purely "
368: "alphanumeric\n", stderr);
369: break;
370: }
1.1 deraadt 371: }
1.28 millert 372: if (*p == '\0')
373: break; /* Valid seed */
374: }
1.38 millert 375: if (newseed[0] != '\0')
1.44 deraadt 376: (void)strlcpy(seed, newseed, seedlen);
1.1 deraadt 377:
1.28 millert 378: for (i = 0; ; i++) {
379: if (i >= 2)
380: exit(1);
381:
382: (void)printf("otp-%s %d %s\nS/Key access password: ",
383: skey_get_algorithm(), n, seed);
384: (void)fgets(buf, bufsiz, stdin);
385: clearerr(stdin);
386: rip(buf);
387: backspace(buf);
388:
389: if (buf[0] == '?') {
390: (void)puts("Enter 6 words from secure S/Key calculation.");
391: continue;
392: } else if (buf[0] == '\0')
393: exit(1);
394:
395: if (etob(key, buf) == 1 || atob8(key, buf) == 0)
396: break; /* Valid format */
397: (void)fputs("ERROR: Invalid format - try again with the 6 words.\n",
398: stderr);
1.1 deraadt 399: }
1.28 millert 400: *count= n;
401: }
1.1 deraadt 402:
1.28 millert 403: void
1.38 millert 404: normal_mode(char *username, int n, char *key, char *seed)
1.28 millert 405: {
406: int i, nn;
1.38 millert 407: char passwd[SKEY_MAX_PW_LEN+2], key2[SKEY_BINKEY_SIZE];
1.1 deraadt 408:
1.28 millert 409: /* Get user's secret passphrase */
410: for (i = 0; ; i++) {
411: if (i > 2)
1.38 millert 412: errx(1, "S/Key entry not updated");
1.28 millert 413:
1.46 otto 414: if (readpassphrase("Enter new secret passphrase: ", passwd,
1.28 millert 415: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
416: exit(1);
417:
418: if (strlen(passwd) < SKEY_MIN_PW_LEN) {
419: (void)fprintf(stderr,
420: "ERROR: Your passphrase must be at least %d "
421: "characters long.\n", SKEY_MIN_PW_LEN);
422: continue;
423: } else if (strcmp(passwd, username) == 0) {
424: (void)fputs("ERROR: Your passphrase may not be the "
425: "same as your user name.\n", stderr);
426: continue;
1.50 ! deraadt 427: } else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") ==
1.28 millert 428: strlen(passwd)) {
429: (void)fputs("ERROR: Your passphrase must contain more "
430: "than just lower case letters.\nWhitespace, "
1.37 aaron 431: "numbers, and punctuation are suggested.\n",
432: stderr);
1.28 millert 433: continue;
434: } else if (strlen(passwd) > 63) {
435: (void)fprintf(stderr, "WARNING: Your passphrase is "
436: "longer than the recommended maximum length of 63\n");
437: }
438: /* XXX - should check for passphrase that is really too long */
1.13 millert 439:
1.38 millert 440: /* Crunch seed and passphrase into starting key */
441: nn = keycrunch(key, seed, passwd);
442: memset(passwd, 0, sizeof(passwd));
443: if (nn != 0)
444: err(2, "key crunch failed");
445:
446: if (readpassphrase("Again secret passphrase: ", passwd,
447: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
448: exit(1);
449:
450: /* Crunch seed and passphrase into starting key */
451: nn = keycrunch(key2, seed, passwd);
452: memset(passwd, 0, sizeof(passwd));
453: if (nn != 0)
454: err(2, "key crunch failed");
455:
456: if (memcmp(key, key2, sizeof(key2)) == 0)
1.28 millert 457: break;
1.1 deraadt 458:
1.28 millert 459: (void)fputs("Passphrases do not match.\n", stderr);
1.20 millert 460: }
1.28 millert 461:
462: nn = n;
463: while (nn-- != 0)
464: f(key);
465: }
466:
1.32 millert 467: void
1.36 millert 468: enable_db(int op)
1.32 millert 469: {
470: if (op == 1) {
471: /* enable */
472: if (mkdir(_PATH_SKEYDIR, 01730) != 0 && errno != EEXIST)
473: err(1, "can't mkdir %s", _PATH_SKEYDIR);
1.33 millert 474: if (chown(_PATH_SKEYDIR, geteuid(), getegid()) != 0)
475: err(1, "can't chown %s", _PATH_SKEYDIR);
1.32 millert 476: if (chmod(_PATH_SKEYDIR, 01730) != 0)
477: err(1, "can't chmod %s", _PATH_SKEYDIR);
478: } else {
479: /* disable */
480: if (chmod(_PATH_SKEYDIR, 0) != 0 && errno != ENOENT)
481: err(1, "can't chmod %s", _PATH_SKEYDIR);
482: }
483: }
484:
485: #define _PATH_SKEYKEYS "/etc/skeykeys"
486: void
487: convert_db(void)
488: {
489: struct passwd *pp;
490: uid_t uid;
491: FILE *keyfile;
492: FILE *newfile;
493: char buf[256], *logname, *hashtype, *seed, *val, *cp;
494: char filename[PATH_MAX];
495: int fd, n;
496:
497: if ((keyfile = fopen(_PATH_SKEYKEYS, "r")) == NULL)
498: err(1, "can't open %s", _PATH_SKEYKEYS);
499: if (flock(fileno(keyfile), LOCK_EX) != 0)
500: err(1, "can't lock %s", _PATH_SKEYKEYS);
1.34 millert 501: enable_db(1);
1.32 millert 502:
503: /*
504: * Loop over each entry in _PATH_SKEYKEYS, creating a file
505: * in _PATH_SKEYDIR for each one.
506: */
507: while (fgets(buf, sizeof(buf), keyfile) != NULL) {
508: if (buf[0] == '#')
509: continue;
510: if ((logname = strtok(buf, " \t")) == NULL)
511: continue;
512: if ((cp = strtok(NULL, " \t")) == NULL)
513: continue;
514: if (isalpha(*cp)) {
515: hashtype = cp;
516: if ((cp = strtok(NULL, " \t")) == NULL)
517: continue;
518: } else
519: hashtype = "md4";
520: n = atoi(cp);
521: if ((seed = strtok(NULL, " \t")) == NULL)
522: continue;
523: if ((val = strtok(NULL, " \t")) == NULL)
524: continue;
525:
526: if ((pp = getpwnam(logname)) != NULL)
527: uid = pp->pw_uid;
528: else
529: uid = 0;
530:
531: /* Now write the new-style record. */
532: if (snprintf(filename, sizeof(filename), "%s/%s", _PATH_SKEYDIR,
533: logname) >= sizeof(filename)) {
534: errno = ENAMETOOLONG;
535: warn("%s", logname);
536: continue;
537: }
538: fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
539: if (fd == -1 || flock(fd, LOCK_EX) != 0 ||
540: (newfile = fdopen(fd, "r+")) == NULL) {
541: warn("%s", logname);
542: continue;
543: }
544: (void)fprintf(newfile, "%s\n%s\n%04d\n%s\n%s\n", logname,
545: hashtype, n, seed, val);
546: (void)fchown(fileno(newfile), uid, -1);
547: (void)fclose(newfile);
548: }
549: printf("%s has been populated. NOTE: %s has *not* been removed.\n"
550: "It should be removed once you have verified that the new keys "
551: "work.\n", _PATH_SKEYDIR, _PATH_SKEYKEYS);
1.8 millert 552: }
553:
554: void
1.36 millert 555: usage(void)
1.8 millert 556: {
1.36 millert 557: extern char *__progname;
558:
559: (void)fprintf(stderr, "usage: %s [-r] [-s] [-x] [-C] [-D] [-E] "
1.32 millert 560: "[-a auth_type] [-n count]\n "
1.36 millert 561: "[-md4|-md5|-sha1|-rmd160] [user]\n", __progname);
1.8 millert 562: exit(1);
1.1 deraadt 563: }