Annotation of src/usr.bin/skeyinit/skeyinit.c, Revision 1.74
1.74 ! millert 1: /* $OpenBSD: skeyinit.c,v 1.73 2018/04/26 12:42:51 guenther 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>
1.74 ! millert 10: * Todd C. Miller <millert@openbsd.org>
1.20 millert 11: *
1.28 millert 12: * S/Key initialization and seed update
1.1 deraadt 13: */
14:
1.32 millert 15: #include <sys/stat.h>
1.1 deraadt 16:
1.32 millert 17: #include <ctype.h>
1.19 millert 18: #include <err.h>
1.20 millert 19: #include <errno.h>
1.73 guenther 20: #include <fcntl.h>
1.19 millert 21: #include <pwd.h>
1.28 millert 22: #include <readpassphrase.h>
1.1 deraadt 23: #include <stdio.h>
24: #include <stdlib.h>
25: #include <string.h>
1.19 millert 26: #include <syslog.h>
27: #include <time.h>
1.1 deraadt 28: #include <unistd.h>
1.56 deraadt 29: #include <limits.h>
1.6 millert 30: #include <utmp.h>
1.19 millert 31:
1.4 millert 32: #include <skey.h>
1.32 millert 33: #include <bsd_auth.h>
1.1 deraadt 34:
1.4 millert 35: #ifndef SKEY_NAMELEN
1.17 millert 36: #define SKEY_NAMELEN 4
1.4 millert 37: #endif
1.1 deraadt 38:
1.36 millert 39: void usage(void);
1.44 deraadt 40: void secure_mode(int *, char *, char *, size_t, char *, size_t);
1.38 millert 41: void normal_mode(char *, int, char *, char *);
1.32 millert 42: void enable_db(int);
1.8 millert 43:
1.1 deraadt 44: int
1.36 millert 45: main(int argc, char **argv)
1.1 deraadt 46: {
1.60 tim 47: int rval, i, l, n, defaultsetup, rmkey, hexmode, enable;
1.56 deraadt 48: char hostname[HOST_NAME_MAX+1];
1.38 millert 49: char seed[SKEY_MAX_SEED_LEN + 1];
1.32 millert 50: char buf[256], key[SKEY_BINKEY_SIZE], filename[PATH_MAX], *ht;
1.72 tb 51: char lastc, *p, *auth_type;
1.57 deraadt 52: const char *errstr;
1.1 deraadt 53: struct skey skey;
54: struct passwd *pp;
1.62 deraadt 55:
1.60 tim 56: n = rmkey = hexmode = enable = 0;
1.32 millert 57: defaultsetup = 1;
58: ht = auth_type = NULL;
1.4 millert 59:
1.8 millert 60: for (i = 1; i < argc && argv[i][0] == '-' && strcmp(argv[i], "--");) {
61: if (argv[i][2] == '\0') {
62: /* Single character switch */
63: switch (argv[i][1]) {
1.32 millert 64: case 'a':
65: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 66: usage();
1.48 otto 67: auth_type = argv[i];
1.32 millert 68: break;
1.4 millert 69: case 's':
70: defaultsetup = 0;
1.48 otto 71: if (auth_type == NULL)
72: auth_type = "skey";
1.4 millert 73: break;
74: case 'x':
75: hexmode = 1;
76: break;
1.35 millert 77: case 'r':
78: rmkey = 1;
1.4 millert 79: break;
1.17 millert 80: case 'n':
1.23 deraadt 81: if (argv[++i] == NULL || argv[i][0] == '\0')
1.36 millert 82: usage();
1.57 deraadt 83: n = strtonum(argv[i], 1, SKEY_MAX_SEQ - 1, &errstr);
84: if (errstr)
1.17 millert 85: errx(1, "count must be > 0 and < %d",
86: SKEY_MAX_SEQ);
87: break;
1.32 millert 88: case 'D':
89: enable = -1;
90: break;
91: case 'E':
92: enable = 1;
93: break;
1.8 millert 94: default:
1.36 millert 95: usage();
1.8 millert 96: }
97: } else {
98: /* Multi character switches are hash types */
99: if ((ht = skey_set_algorithm(&argv[i][1])) == NULL) {
100: warnx("Unknown hash algorithm %s", &argv[i][1]);
1.36 millert 101: usage();
1.8 millert 102: }
1.7 millert 103: }
1.8 millert 104: i++;
1.7 millert 105: }
1.32 millert 106: argv += i;
107: argc -= i;
1.7 millert 108:
1.60 tim 109: if (argc > 1 || (enable && argc))
1.36 millert 110: usage();
1.32 millert 111:
1.60 tim 112: /* Handle -D and -E */
113: if (enable) {
114: enable_db(enable);
1.34 millert 115: exit(0);
116: }
1.69 tb 117:
1.70 millert 118: if (getuid() != 0) {
119: if (pledge("stdio rpath wpath cpath fattr flock tty proc exec "
120: "getpw", NULL) == -1)
121: err(1, "pledge");
1.72 tb 122:
123: if ((pp = getpwuid(getuid())) == NULL)
124: err(1, "no user with uid %u", getuid());
125:
126: if (argc == 1) {
127: char me[UT_NAMESIZE + 1];
128:
129: (void)strlcpy(me, pp->pw_name, sizeof me);
130: if ((pp = getpwnam(argv[0])) == NULL)
131: errx(1, "User unknown: %s", argv[0]);
132: if (strcmp(pp->pw_name, me) != 0)
133: errx(1, "Permission denied.");
134: }
135: } else {
1.70 millert 136: if (pledge("stdio rpath wpath cpath fattr flock tty getpw id",
137: NULL) == -1)
138: err(1, "pledge");
1.69 tb 139:
1.72 tb 140: if (argc == 1) {
141: if ((pp = getpwnam(argv[0])) == NULL) {
1.16 millert 142: static struct passwd _pp;
143:
1.36 millert 144: _pp.pw_name = argv[0];
1.16 millert 145: pp = &_pp;
1.36 millert 146: warnx("Warning, user unknown: %s", argv[0]);
1.16 millert 147: } else {
1.72 tb 148: /* So the file ends up owned by the proper ID */
149: if (setresuid(-1, pp->pw_uid, -1) != 0)
150: errx(1, "unable to change uid to %u",
151: pp->pw_uid);
1.16 millert 152: }
1.72 tb 153: } else if ((pp = getpwuid(0)) == NULL)
154: err(1, "no user with uid 0");
155:
156: if (pledge("stdio rpath wpath cpath fattr flock tty", NULL)
157: == -1)
158: err(1, "pledge");
1.1 deraadt 159: }
160:
1.41 millert 161: switch (skey_haskey(pp->pw_name)) {
162: case -1:
163: if (errno == ENOENT || errno == EPERM)
164: errx(1, "S/Key disabled");
165: else
166: err(1, "cannot open database");
167: break;
168: case 0:
169: /* existing user */
170: break;
171: case 1:
1.48 otto 172: if (!defaultsetup && strcmp(auth_type, "skey") == 0) {
1.41 millert 173: fprintf(stderr,
1.45 espie 174: "You must authenticate yourself before using S/Key for the first time. In\n"
175: "secure mode this is normally done via an existing S/Key key. However, since\n"
176: "you do not have an entry in the S/Key database you will have to specify an\n"
177: "alternate authentication type via the `-a' flag, e.g.\n"
1.54 ajacouto 178: " \"skeyinit -s -a passwd\"\n\n"
1.45 espie 179: "Note that entering a plaintext password over a non-secure link defeats the\n"
180: "purpose of using S/Key in the fist place.\n");
1.41 millert 181: exit(1);
182: }
183: break;
184: }
1.28 millert 185:
1.1 deraadt 186: if (getuid() != 0) {
1.32 millert 187: if ((pp = pw_dup(pp)) == NULL)
188: err(1, NULL);
189: if (!auth_userokay(pp->pw_name, auth_type, NULL, NULL))
190: errx(1, "Password incorrect");
1.10 millert 191: }
1.67 millert 192:
193: if (pledge("stdio rpath wpath cpath fattr flock tty", NULL) == -1)
194: err(1, "pledge");
1.71 tb 195:
196: /* Build up a default seed based on the hostname and some randomness */
197: if (gethostname(hostname, sizeof(hostname)) < 0)
198: err(1, "gethostname");
199: for (i = 0, p = seed; hostname[i] && i < SKEY_NAMELEN; i++) {
200: if (isalnum((unsigned char)hostname[i]))
201: *p++ = tolower((unsigned char)hostname[i]);
202: }
203: for (i = 0; i < 5; i++)
204: *p++ = arc4random_uniform(10) + '0';
205: *p = '\0';
1.1 deraadt 206:
1.28 millert 207: /*
208: * Lookup and lock the record we are about to modify.
209: * If this is a new entry this will prevent other users
210: * from appending new entries (and clobbering ours).
211: */
1.1 deraadt 212: rval = skeylookup(&skey, pp->pw_name);
213: switch (rval) {
1.4 millert 214: case -1:
1.41 millert 215: err(1, "cannot open database");
1.21 millert 216: break;
1.4 millert 217: case 0:
1.35 millert 218: /* remove user if asked to do so */
219: if (rmkey) {
220: if (snprintf(filename, sizeof(filename),
221: "%s/%s", _PATH_SKEYDIR, pp->pw_name)
1.55 guenther 222: >= sizeof(filename))
223: errc(1, ENAMETOOLONG,
224: "Cannot remove S/Key entry");
1.35 millert 225: if (unlink(filename) != 0)
226: err(1, "Cannot remove S/Key entry");
227: printf("S/Key entry for %s removed.\n",
228: pp->pw_name);
229: exit(0);
230: }
1.4 millert 231:
1.28 millert 232: (void)printf("[Updating %s with %s]\n", pp->pw_name,
233: ht ? ht : skey_get_algorithm());
234: (void)printf("Old seed: [%s] %s\n",
235: skey_get_algorithm(), skey.seed);
1.4 millert 236:
237: /*
1.25 millert 238: * Sanity check old seed.
239: */
240: l = strlen(skey.seed);
241: for (p = skey.seed; *p; p++) {
1.52 deraadt 242: if (isalpha((unsigned char)*p)) {
243: if (isupper((unsigned char)*p))
244: *p = tolower((unsigned char)*p);
245: } else if (!isdigit((unsigned char)*p)) {
1.25 millert 246: memmove(p, p + 1, l - (p - skey.seed));
247: l--;
248: }
249: }
250:
1.28 millert 251: /* If the seed ends in 0-8 just add one. */
1.4 millert 252: if (l > 0) {
253: lastc = skey.seed[l - 1];
1.52 deraadt 254: if (isdigit((unsigned char)lastc) &&
255: lastc != '9') {
1.43 deraadt 256: (void)strlcpy(seed, skey.seed,
257: sizeof seed);
1.38 millert 258: seed[l - 1] = lastc + 1;
1.4 millert 259: }
1.52 deraadt 260: if (isdigit((unsigned char)lastc) &&
261: 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",
1.55 guenther 276: _PATH_SKEYDIR, pp->pw_name) >= sizeof(filename))
277: errc(1, ENAMETOOLONG,
278: "Cannot create S/Key entry");
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);
1.64 millert 290: if (defaultsetup && n == 0)
1.47 otto 291: n = 100;
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)
1.44 deraadt 299: secure_mode(&n, key, seed, sizeof 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? */
1.58 deraadt 305: if ((skey.val = malloc(16 + 1)) == NULL)
1.28 millert 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
1.44 deraadt 322: secure_mode(int *count, char *key, char *seed, size_t seedlen,
323: char *buf, size_t bufsiz)
1.28 millert 324: {
1.38 millert 325: char *p, newseed[SKEY_MAX_SEED_LEN + 2];
1.57 deraadt 326: const char *errstr;
1.64 millert 327: int i, n = *count;
1.4 millert 328:
1.28 millert 329: (void)puts("You need the 6 words generated from the \"skey\" command.");
1.64 millert 330: if (n == 0) {
331: for (i = 0; ; i++) {
332: if (i >= 2)
333: exit(1);
334:
335: (void)printf("Enter sequence count from 1 to %d: ",
336: SKEY_MAX_SEQ);
337: (void)fgets(buf, bufsiz, stdin);
338: clearerr(stdin);
339: rip(buf);
340: n = strtonum(buf, 1, SKEY_MAX_SEQ-1, &errstr);
341: if (!errstr)
342: break; /* Valid range */
343: fprintf(stderr,
344: "ERROR: Count must be between 1 and %d\n",
345: SKEY_MAX_SEQ - 1);
346: }
347: *count= n;
1.28 millert 348: }
1.1 deraadt 349:
1.28 millert 350: for (i = 0; ; i++) {
351: if (i >= 2)
352: exit(1);
353:
1.38 millert 354: (void)printf("Enter new seed [default %s]: ", seed);
355: (void)fgets(newseed, sizeof(newseed), stdin); /* XXX */
1.28 millert 356: clearerr(stdin);
1.38 millert 357: rip(newseed);
358: if (strlen(newseed) > SKEY_MAX_SEED_LEN) {
1.28 millert 359: (void)fprintf(stderr, "ERROR: Seed must be between 1 "
360: "and %d characters in length\n", SKEY_MAX_SEED_LEN);
361: continue;
362: }
1.38 millert 363: for (p = newseed; *p; p++) {
1.52 deraadt 364: if (isspace((unsigned char)*p)) {
1.28 millert 365: (void)fputs("ERROR: Seed must not contain "
366: "any spaces\n", stderr);
1.1 deraadt 367: break;
1.52 deraadt 368: } else if (isalpha((unsigned char)*p)) {
369: if (isupper((unsigned char)*p))
370: *p = tolower((unsigned char)*p);
371: } else if (!isdigit((unsigned char)*p)) {
1.28 millert 372: (void)fputs("ERROR: Seed must be purely "
373: "alphanumeric\n", stderr);
374: break;
375: }
1.1 deraadt 376: }
1.28 millert 377: if (*p == '\0')
378: break; /* Valid seed */
379: }
1.38 millert 380: if (newseed[0] != '\0')
1.44 deraadt 381: (void)strlcpy(seed, newseed, seedlen);
1.1 deraadt 382:
1.28 millert 383: for (i = 0; ; i++) {
384: if (i >= 2)
385: exit(1);
386:
387: (void)printf("otp-%s %d %s\nS/Key access password: ",
388: skey_get_algorithm(), n, seed);
389: (void)fgets(buf, bufsiz, stdin);
390: clearerr(stdin);
391: rip(buf);
392: backspace(buf);
393:
394: if (buf[0] == '?') {
395: (void)puts("Enter 6 words from secure S/Key calculation.");
396: continue;
397: } else if (buf[0] == '\0')
398: exit(1);
399:
400: if (etob(key, buf) == 1 || atob8(key, buf) == 0)
401: break; /* Valid format */
402: (void)fputs("ERROR: Invalid format - try again with the 6 words.\n",
403: stderr);
1.1 deraadt 404: }
1.28 millert 405: }
1.1 deraadt 406:
1.28 millert 407: void
1.38 millert 408: normal_mode(char *username, int n, char *key, char *seed)
1.28 millert 409: {
410: int i, nn;
1.38 millert 411: char passwd[SKEY_MAX_PW_LEN+2], key2[SKEY_BINKEY_SIZE];
1.1 deraadt 412:
1.28 millert 413: /* Get user's secret passphrase */
414: for (i = 0; ; i++) {
415: if (i > 2)
1.38 millert 416: errx(1, "S/Key entry not updated");
1.28 millert 417:
1.46 otto 418: if (readpassphrase("Enter new secret passphrase: ", passwd,
1.28 millert 419: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
420: exit(1);
421:
422: if (strlen(passwd) < SKEY_MIN_PW_LEN) {
423: (void)fprintf(stderr,
424: "ERROR: Your passphrase must be at least %d "
425: "characters long.\n", SKEY_MIN_PW_LEN);
426: continue;
427: } else if (strcmp(passwd, username) == 0) {
428: (void)fputs("ERROR: Your passphrase may not be the "
429: "same as your user name.\n", stderr);
430: continue;
1.50 deraadt 431: } else if (strspn(passwd, "abcdefghijklmnopqrstuvwxyz") ==
1.28 millert 432: strlen(passwd)) {
433: (void)fputs("ERROR: Your passphrase must contain more "
434: "than just lower case letters.\nWhitespace, "
1.37 aaron 435: "numbers, and punctuation are suggested.\n",
436: stderr);
1.28 millert 437: continue;
438: } else if (strlen(passwd) > 63) {
439: (void)fprintf(stderr, "WARNING: Your passphrase is "
440: "longer than the recommended maximum length of 63\n");
441: }
442: /* XXX - should check for passphrase that is really too long */
1.13 millert 443:
1.38 millert 444: /* Crunch seed and passphrase into starting key */
445: nn = keycrunch(key, seed, passwd);
1.59 tim 446: explicit_bzero(passwd, sizeof(passwd));
1.38 millert 447: if (nn != 0)
448: err(2, "key crunch failed");
449:
450: if (readpassphrase("Again secret passphrase: ", passwd,
451: sizeof(passwd), 0) == NULL || passwd[0] == '\0')
452: exit(1);
453:
454: /* Crunch seed and passphrase into starting key */
455: nn = keycrunch(key2, seed, passwd);
1.59 tim 456: explicit_bzero(passwd, sizeof(passwd));
1.38 millert 457: if (nn != 0)
458: err(2, "key crunch failed");
459:
460: if (memcmp(key, key2, sizeof(key2)) == 0)
1.28 millert 461: break;
1.1 deraadt 462:
1.28 millert 463: (void)fputs("Passphrases do not match.\n", stderr);
1.20 millert 464: }
1.28 millert 465:
466: nn = n;
467: while (nn-- != 0)
468: f(key);
469: }
470:
1.32 millert 471: void
1.36 millert 472: enable_db(int op)
1.32 millert 473: {
474: if (op == 1) {
475: /* enable */
476: if (mkdir(_PATH_SKEYDIR, 01730) != 0 && errno != EEXIST)
477: err(1, "can't mkdir %s", _PATH_SKEYDIR);
1.33 millert 478: if (chown(_PATH_SKEYDIR, geteuid(), getegid()) != 0)
479: err(1, "can't chown %s", _PATH_SKEYDIR);
1.32 millert 480: if (chmod(_PATH_SKEYDIR, 01730) != 0)
481: err(1, "can't chmod %s", _PATH_SKEYDIR);
482: } else {
483: /* disable */
484: if (chmod(_PATH_SKEYDIR, 0) != 0 && errno != ENOENT)
485: err(1, "can't chmod %s", _PATH_SKEYDIR);
486: }
487: }
488:
1.8 millert 489: void
1.36 millert 490: usage(void)
1.8 millert 491: {
1.36 millert 492: extern char *__progname;
493:
1.60 tim 494: (void)fprintf(stderr, "usage: %s [-DErsx] [-a auth-type] [-n count]"
1.53 naddy 495: "\n\t[-md5 | -rmd160 | -sha1] [user]\n", __progname);
1.8 millert 496: exit(1);
1.1 deraadt 497: }
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