xref: /netbsd-src/lib/libpam/modules/pam_unix/pam_unix.c (revision db6316d1518382eecd2fdbe55a1205e0620a1b35)
1 /*	$NetBSD: pam_unix.c,v 1.2 2004/12/12 08:17:56 christos Exp $	*/
2 
3 /*-
4  * Copyright 1998 Juniper Networks, Inc.
5  * All rights reserved.
6  * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
7  * All rights reserved.
8  *
9  * Portions of this software was developed for the FreeBSD Project by
10  * ThinkSec AS and NAI Labs, the Security Research Division of Network
11  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
12  * ("CBOSS"), as part of the DARPA CHATS research program.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. The name of the author may not be used to endorse or promote
23  *    products derived from this software without specific prior written
24  *    permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #ifdef __FreeBSD__
41 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_unix/pam_unix.c,v 1.49 2004/02/10 10:13:21 des Exp $");
42 #else
43 __RCSID("$NetBSD: pam_unix.c,v 1.2 2004/12/12 08:17:56 christos Exp $");
44 #endif
45 
46 
47 #include <sys/types.h>
48 
49 #include <ctype.h>
50 #include <errno.h>
51 #include <fcntl.h>
52 #include <pwd.h>
53 #include <grp.h>
54 #include <limits.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <stdio.h>
58 #include <login_cap.h>
59 #include <time.h>
60 #include <tzfile.h>
61 #include <unistd.h>
62 
63 #include <util.h>
64 
65 #ifdef YP
66 #include <rpc/rpc.h>
67 #include <rpcsvc/ypclnt.h>
68 #include <rpcsvc/yppasswd.h>
69 #endif
70 
71 #define PAM_SM_AUTH
72 #define PAM_SM_ACCOUNT
73 #define	PAM_SM_PASSWORD
74 
75 #include <security/pam_appl.h>
76 #include <security/pam_modules.h>
77 #include <security/pam_mod_misc.h>
78 
79 /*
80  * authentication management
81  */
82 PAM_EXTERN int
83 /*ARGSUSED*/
84 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
85     int argc __unused, const char *argv[] __unused)
86 {
87 	login_cap_t *lc;
88 	struct passwd *pwd;
89 	int retval;
90 	const char *pass, *user, *realpw;
91 
92 	if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
93 		pwd = getpwnam(getlogin());
94 	} else {
95 		retval = pam_get_user(pamh, &user, NULL);
96 		if (retval != PAM_SUCCESS)
97 			return (retval);
98 		PAM_LOG("Got user: %s", user);
99 		pwd = getpwnam(user);
100 	}
101 
102 	if (pwd != NULL) {
103 		PAM_LOG("Doing real authentication");
104 		realpw = pwd->pw_passwd;
105 		if (realpw[0] == '\0') {
106 			if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) &&
107 			    openpam_get_option(pamh, PAM_OPT_NULLOK))
108 				return (PAM_SUCCESS);
109 			realpw = "*";
110 		}
111 		lc = login_getpwclass(pwd);
112 	} else {
113 		PAM_LOG("Doing dummy authentication");
114 		realpw = "*";
115 		lc = login_getclass(NULL);
116 	}
117 	retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, NULL);
118 	login_close(lc);
119 	if (retval != PAM_SUCCESS)
120 		return (retval);
121 	PAM_LOG("Got password");
122 	if (strcmp(crypt(pass, realpw), realpw) == 0)
123 		return (PAM_SUCCESS);
124 
125 	PAM_VERBOSE_ERROR("UNIX authentication refused");
126 	return (PAM_AUTH_ERR);
127 }
128 
129 PAM_EXTERN int
130 /*ARGSUSED*/
131 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
132     int argc __unused, const char *argv[] __unused)
133 {
134 
135 	return (PAM_SUCCESS);
136 }
137 
138 /*
139  * account management
140  */
141 PAM_EXTERN int
142 /*ARGSUSED*/
143 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
144     int argc __unused, const char *argv[] __unused)
145 {
146 	struct passwd *pwd;
147 	struct timeval now;
148 	login_cap_t *lc;
149 	time_t warntime;
150 	int retval;
151 	const char *user;
152 
153 	retval = pam_get_user(pamh, &user, NULL);
154 	if (retval != PAM_SUCCESS)
155 		return (retval);
156 
157 	if (user == NULL || (pwd = getpwnam(user)) == NULL)
158 		return (PAM_SERVICE_ERR);
159 
160 	PAM_LOG("Got user: %s", user);
161 
162 	if (*pwd->pw_passwd == '\0' &&
163 	    (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0)
164 		return (PAM_NEW_AUTHTOK_REQD);
165 
166 	lc = login_getpwclass(pwd);
167 	if (lc == NULL) {
168 		PAM_LOG("Unable to get login class for user %s", user);
169 		return (PAM_SERVICE_ERR);
170 	}
171 
172 	PAM_LOG("Got login_cap");
173 
174 	if (pwd->pw_change || pwd->pw_expire)
175 		(void) gettimeofday(&now, NULL);
176 
177 	warntime = (time_t)login_getcaptime(lc, "password-warn",
178 	    (quad_t)(_PASSWORD_WARNDAYS * SECSPERDAY),
179 	    (quad_t)(_PASSWORD_WARNDAYS * SECSPERDAY));
180 
181 	/*
182 	 * Check pw_expire before pw_change - no point in letting the
183 	 * user change the password on an expired account.
184 	 */
185 
186 	if (pwd->pw_expire) {
187 		if (now.tv_sec >= pwd->pw_expire) {
188 			login_close(lc);
189 			return (PAM_ACCT_EXPIRED);
190 		} else if (pwd->pw_expire - now.tv_sec < warntime &&
191 		    (flags & PAM_SILENT) == 0) {
192 			pam_error(pamh, "Warning: your account expires on %s",
193 			    ctime(&pwd->pw_expire));
194 		}
195 	}
196 
197 	if (pwd->pw_change) {
198 		/* XXX How to handle _PASSWORD_CHGNOW?  --thorpej */
199 		if (now.tv_sec >= pwd->pw_change) {
200 			login_close(lc);
201 			return (PAM_NEW_AUTHTOK_REQD);
202 		} else if (pwd->pw_change - now.tv_sec < warntime &&
203 		    (flags & PAM_SILENT) == 0) {
204 			pam_error(pamh, "Warning: your password expires on %s",
205 			    ctime(&pwd->pw_change));
206 		}
207 	}
208 
209 	login_close(lc);
210 
211 	return (PAM_SUCCESS);
212 }
213 
214 static int pwd_gensalt(char *, int, struct passwd *, char);
215 
216 #ifdef YP
217 /*
218  * yp_check_user:
219  *
220  *	Helper function; check that a user exists in the NIS
221  *	password map.
222  */
223 static int
224 yp_check_user(const char *domain, const char *user)
225 {
226 	char *val;
227 	int reason, vallen;
228 
229 	val = NULL;
230 	reason = yp_match(domain, "passwd.byname", user, (int)strlen(user),
231 	    &val, &vallen);
232 	if (reason != 0) {
233 		if (val != NULL)
234 			free(val);
235 		return (0);
236 	}
237 	free(val);
238 	return (1);
239 }
240 
241 static int
242 /*ARGSUSED*/
243 yp_set_password(pam_handle_t *pamh, struct passwd *opwd,
244     struct passwd *pwd, const char *old_pass, const char *domain)
245 {
246 	char *master;
247 	int r, rpcport, status;
248 	struct yppasswd yppwd;
249 	CLIENT *client;
250 	uid_t uid;
251 	int retval = PAM_SERVICE_ERR;
252 	struct timeval tv;
253 
254 	/*
255 	 * Find the master for the passwd map; it should be running
256 	 * rpc.yppasswdd.
257 	 */
258 	if ((r = yp_master(domain, "passwd.byname", &master)) != 0) {
259 		pam_error(pamh, "Can't find master NIS server.  Reason: %s",
260 		    yperr_string(r));
261 		return (PAM_SERVICE_ERR);
262 	}
263 
264 	/*
265 	 * Ask the portmapper for the port of rpc.yppasswdd.
266 	 */
267 	if ((rpcport = getrpcport(master, YPPASSWDPROG,
268 				  YPPASSWDPROC_UPDATE, IPPROTO_UDP)) == 0) {
269 		pam_error(pamh,
270 		    "Master NIS server not runing yppasswd daemon.\n\t"
271 		    "Can't change NIS password.");
272 		return (PAM_SERVICE_ERR);
273 	}
274 
275 	/*
276 	 * Be sure the port is privileged.
277 	 */
278 	if (rpcport >= IPPORT_RESERVED) {
279 		pam_error(pamh, "yppasswd daemon is on an invalid port.");
280 		return (PAM_SERVICE_ERR);
281 	}
282 
283 	uid = getuid();
284 	if (uid != 0 && uid != pwd->pw_uid) {
285 		pam_error(pamh, "You may only change your own password: %s",
286 		    strerror(EACCES));
287 		return (PAM_SERVICE_ERR);
288 	}
289 
290 	/*
291 	 * Fill in the yppasswd structure for yppasswdd.
292 	 */
293 	memset(&yppwd, 0, sizeof(yppwd));
294 	if ((yppwd.newpw.pw_passwd = strdup(pwd->pw_passwd)) == NULL)
295 		goto malloc_failure;
296 	if ((yppwd.newpw.pw_name = strdup(pwd->pw_name)) == NULL)
297 		goto malloc_failure;
298 	yppwd.newpw.pw_uid = pwd->pw_uid;
299 	yppwd.newpw.pw_gid = pwd->pw_gid;
300 	if ((yppwd.newpw.pw_gecos = strdup(pwd->pw_gecos)) == NULL)
301 		goto malloc_failure;
302 	if ((yppwd.newpw.pw_dir = strdup(pwd->pw_dir)) == NULL)
303 		goto malloc_failure;
304 	if ((yppwd.newpw.pw_shell = strdup(pwd->pw_shell)) == NULL)
305 		goto malloc_failure;
306 
307 	client = clnt_create(master, YPPASSWDPROG, YPPASSWDVERS, "udp");
308 	if (client == NULL) {
309 		pam_error(pamh, "Can't contact yppasswdd on %s: Reason: %s",
310 		    master, yperr_string(YPERR_YPBIND));
311 		goto out;
312 	}
313 
314 	client->cl_auth = authunix_create_default();
315 	tv.tv_sec = 2;
316 	tv.tv_usec = 0;
317 	r = clnt_call(client, YPPASSWDPROC_UPDATE,
318 	    xdr_yppasswd, &yppwd, xdr_int, &status, tv);
319 	if (r)
320 		pam_error(pamh, "RPC to yppasswdd failed.");
321 	else if (status)
322 		pam_error(pamh, "Couldn't change NIS password.");
323 	else {
324 		pam_info(pamh, "The NIS password has been changed on %s, "
325 		    "the master NIS passwd server.", master);
326 		retval = PAM_SUCCESS;
327 	}
328 
329  out:
330 	if (yppwd.newpw.pw_passwd != NULL)
331 		free(yppwd.newpw.pw_passwd);
332 	if (yppwd.newpw.pw_name != NULL)
333 		free(yppwd.newpw.pw_name);
334 	if (yppwd.newpw.pw_gecos != NULL)
335 		free(yppwd.newpw.pw_gecos);
336 	if (yppwd.newpw.pw_dir != NULL)
337 		free(yppwd.newpw.pw_dir);
338 	if (yppwd.newpw.pw_shell != NULL)
339 		free(yppwd.newpw.pw_shell);
340 	return (retval);
341 
342  malloc_failure:
343 	pam_error(pamh, "memory allocation failure");
344 	goto out;
345 }
346 #endif /* YP */
347 
348 static int
349 local_set_password(pam_handle_t *pamh, struct passwd *opwd,
350     struct passwd *pwd)
351 {
352 	char errbuf[200];
353 	int tfd, pfd;
354 
355 	pw_init();
356 	tfd = pw_lock(0);
357 	if (tfd < 0) {
358 		pam_error(pamh, "The password file is busy, waiting...");
359 		tfd = pw_lock(10);
360 		if (tfd < 0) {
361 			pam_error(pamh, "The password file is still busy, "
362 			    "try again later.");
363 			return (PAM_SERVICE_ERR);
364 		}
365 	}
366 
367 	pfd = open(_PATH_MASTERPASSWD, O_RDONLY, 0);
368 	if (pfd < 0) {
369 		pam_error(pamh, "%s: %s", _PATH_MASTERPASSWD, strerror(errno));
370 		pw_abort();
371 		return (PAM_SERVICE_ERR);
372 	}
373 
374 	if (pw_copyx(pfd, tfd, pwd, opwd, errbuf, sizeof(errbuf)) == 0) {
375 		pam_error(pamh, "Unable to update password entry: %s",
376 		    errbuf);
377 		pw_abort();
378 		return (PAM_SERVICE_ERR);
379 	}
380 
381 	if (pw_mkdb(pwd->pw_name, opwd->pw_change == pwd->pw_change) < 0) {
382 		pam_error(pamh, "Unable to rebuild local password database.");
383 		pw_abort();
384 		return (PAM_SERVICE_ERR);
385 	}
386 
387 	return (PAM_SUCCESS);
388 }
389 
390 /*
391  * password management
392  *
393  * standard Unix and NIS password changing
394  */
395 PAM_EXTERN int
396 /*ARGSUSED*/
397 pam_sm_chauthtok(pam_handle_t *pamh, int flags,
398     int argc __unused, const char *argv[] __unused)
399 {
400 	struct passwd *pwd, old_pwd;
401 	login_cap_t *lc;
402 	const char *user, *passwd_db, *new_pass, *old_pass, *p;
403 	int retval, tries, min_pw_len = 0, pw_expiry = 0;
404 	char salt[_PASSWORD_LEN+1];
405 #ifdef YP
406 	char *domain;
407 	int r;
408 #endif
409 
410 	if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF))
411 		pwd = getpwnam(getlogin());
412 	else {
413 		retval = pam_get_user(pamh, &user, NULL);
414 		if (retval != PAM_SUCCESS)
415 			return (retval);
416 		pwd = getpwnam(user);
417 	}
418 
419 	if (pwd == NULL)
420 		return (PAM_AUTHTOK_RECOVERY_ERR);
421 
422 	old_pwd = *pwd;
423 
424 	PAM_LOG("Got user: %s", user);
425 
426 	/*
427 	 * Determine which password type we're going to change, and
428 	 * remember it.
429 	 *
430 	 * NOTE: domain does not need to be freed; its storage is
431 	 * allocated statically in libc.
432 	 */
433 	passwd_db = openpam_get_option(pamh, "passwd_db");
434 	if (passwd_db == NULL) {
435 #ifdef YP
436 		/* Prefer YP, if configured. */
437 		if (_yp_check(NULL)) {
438 			/* If _yp_check() succeeded, then this must. */
439 			if ((r = yp_get_default_domain(&domain)) != 0) {
440 				pam_error(pamh,
441 				    "Unable to get NIS domain, reason: %s",
442 				    yperr_string(r));
443 				return (PAM_SERVICE_ERR);
444 			}
445 			if (yp_check_user(domain, user))
446 				passwd_db = "nis";
447 		}
448 #endif
449 		/* Otherwise we always use local files. */
450 		if (passwd_db == NULL) {
451 			/* XXX Any validation to do here? */
452 			passwd_db = "files";
453 		}
454 
455 		if (passwd_db == NULL) {
456 			pam_error(pamh, "Unable to determine Unix password DB");
457 			return (PAM_SERVICE_ERR);
458 		} else if ((retval = openpam_set_option(pamh, "passwd_db",
459 						passwd_db)) != PAM_SUCCESS) {
460 			return (retval);
461 		}
462 	} else {
463 		/* Check to see if the specified password DB is usable. */
464 #ifdef YP
465 		if (strcmp(passwd_db, "nis") == 0) {
466 			if (_yp_check(NULL) == 0) {
467 				pam_error(pamh, "NIS not in use.");
468 				return (PAM_SERVICE_ERR);
469 			}
470 			if ((r = yp_get_default_domain(&domain)) != 0) {
471 				pam_error(pamh,
472 				    "Unable to get NIS domain, reason: %s",
473 				    yperr_string(r));
474 				return (PAM_SERVICE_ERR);
475 			}
476 			if (yp_check_user(domain, user) == 0) {
477 				pam_error(pamh,
478 				    "User %s does not exist in NIS.", user);
479 				return (PAM_USER_UNKNOWN);
480 			}
481 			goto known_passwd_db;
482 		}
483 #endif
484 		if (strcmp(passwd_db, "files") == 0) {
485 			/* XXX Any validation to do here? */
486 			goto known_passwd_db;
487 		}
488 		pam_error(pamh, "Unknown Unix password DB: %s", passwd_db);
489 		return (PAM_SERVICE_ERR);
490 	}
491  known_passwd_db:
492 
493 	if (flags & PAM_PRELIM_CHECK) {
494 		PAM_LOG("PRELIM round");
495 
496 		if (strcmp(passwd_db, "files") == 0) {
497 			if (getuid() == 0) {
498 				/* Root doesn't need the old password. */
499 				return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
500 			}
501 		}
502 
503 		if (pwd->pw_passwd[0] == '\0') {
504 			/*
505 			 * No password case.
506 			 * XXX Are we giviing too much away by not prompting
507 			 * XXX for a password?
508 			 * XXX Check PAM_DISALLOW_NULL_AUTHTOK
509 			 */
510 			return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
511 		} else {
512 			retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK,
513 			    &old_pass, NULL);
514 			if (retval != PAM_SUCCESS)
515 				return (retval);
516 			if (strcmp(crypt(old_pass, pwd->pw_passwd),
517 				   pwd->pw_passwd) != 0)
518 				return (PAM_PERM_DENIED);
519 			return (PAM_SUCCESS);
520 		}
521 	}
522 
523 	if (flags & PAM_UPDATE_AUTHTOK) {
524 		PAM_LOG("UPDATE round");
525 
526 		if ((lc = login_getclass(pwd->pw_class)) != NULL) {
527 			min_pw_len = (int) login_getcapnum(lc,
528 			    "minpasswordlen", (quad_t)0, (quad_t)0);
529 			pw_expiry = (int) login_getcapnum(lc,
530 			    "passwordtime", (quad_t)0, (quad_t)0);
531 			login_close(lc);
532 		}
533 
534 		retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &old_pass, NULL);
535 		if (retval != PAM_SUCCESS)
536 			return (retval);
537 
538 		/* Get the new password. */
539 		for (tries = 0;;) {
540 			retval = pam_get_authtok(pamh, PAM_AUTHTOK, &new_pass,
541 			    NULL);
542 			if (retval == PAM_TRY_AGAIN) {
543 				pam_error(pamh,
544 				    "Mismatch; try again, EOF to quit.");
545 				continue;
546 			}
547 			if (retval != PAM_SUCCESS) {
548 				PAM_VERBOSE_ERROR("Unable to get new password");
549 				return (retval);
550 			}
551 			/* Successfully got new password. */
552 			if (new_pass[0] == '\0') {
553 				pam_info(pamh, "Password unchanged.");
554 				return (PAM_SUCCESS);
555 			}
556 			if (min_pw_len > 0 && strlen(new_pass) < min_pw_len) {
557 				pam_error(pamh, "Password is too short.");
558 				continue;
559 			}
560 			if (strlen(new_pass) <= 5 && ++tries < 2) {
561 				pam_error(pamh,
562 				    "Please enter a longer password.");
563 				continue;
564 			}
565 			for (p = new_pass; *p && islower((unsigned char)*p); ++p);
566 			if (!*p && ++tries < 2) {
567 				pam_error(pamh,
568 				    "Please don't use an all-lower case "
569 				    "password.\nUnusual capitalization, "
570 				    "control characters or digits are "
571 				    "suggested.");
572 				continue;
573 			}
574 			/* Password is OK. */
575 			break;
576 		}
577 
578 		if (pwd_gensalt(salt, _PASSWORD_LEN, pwd,
579 #ifdef YP
580 		    strcmp(passwd_db, "nis") == 0 ? 'y' :
581 #endif
582 		    'l') == 0) {
583 			pam_error(pamh, "Couldn't generate salt.");
584 			return (PAM_SERVICE_ERR);
585 		}
586 
587 		pwd->pw_passwd = crypt(new_pass, salt);
588 		pwd->pw_change = pw_expiry ? pw_expiry + time(NULL) : 0;
589 
590 		retval = PAM_SERVICE_ERR;
591 		if (strcmp(passwd_db, "files") == 0)
592 			retval = local_set_password(pamh, &old_pwd, pwd);
593 #ifdef YP
594 		if (strcmp(passwd_db, "nis") == 0)
595 			retval = yp_set_password(pamh, &old_pwd, pwd, old_pass,
596 			    domain);
597 #endif
598 		return (retval);
599 	}
600 
601 	PAM_LOG("Illegal flags argument");
602 	return (PAM_ABORT);
603 }
604 
605 PAM_MODULE_ENTRY("pam_unix");
606 
607 /*
608  * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
609  * All rights reserved.
610  *
611  * Redistribution and use in source and binary forms, with or without
612  * modification, are permitted provided that the following conditions
613  * are met:
614  * 1. Redistributions of source code must retain the above copyright
615  *    notice, this list of conditions and the following disclaimer.
616  * 2. Redistributions in binary form must reproduce the above copyright
617  *    notice, this list of conditions and the following disclaimer in the
618  *    documentation and/or other materials provided with the distribution.
619  * 3. All advertising materials mentioning features or use of this software
620  *    must display the following acknowledgement:
621  *      This product includes software developed by Niels Provos.
622  * 4. The name of the author may not be used to endorse or promote products
623  *    derived from this software without specific prior written permission.
624  *
625  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
626  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
627  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
628  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
629  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
630  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
631  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
632  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
633  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
634  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
635  */
636 
637 static const unsigned char itoa64[] =	 /* 0 ... 63 => ascii - 64 */
638 	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
639 
640 static void
641 to64(char *s, uint32_t v, int n)
642 {
643 
644 
645 	while (--n >= 0) {
646 		*s++ = itoa64[v & 0x3f];
647 		v >>= 6;
648 	}
649 }
650 
651 static int
652 pwd_gensalt(char *salt, int max, struct passwd *pwd, char type)
653 {
654 	char option[LINE_MAX], *next, *now, grpkey[LINE_MAX];
655 	const char *cipher;
656 	int rounds;
657 	struct group *grp;
658 
659 	*salt = '\0';
660 
661 	switch (type) {
662 	case 'y':
663 	        cipher = "ypcipher";
664 		break;
665 	case 'l':
666 	default:
667 	        cipher = "localcipher";
668 		break;
669 	}
670 
671 	pw_getconf(option, sizeof(option), pwd->pw_name, cipher);
672 
673 	/* Try to find an entry for the group */
674 	if (*option == 0) {
675 		if ((grp = getgrgid(pwd->pw_gid)) != NULL) {
676 			snprintf(grpkey, sizeof(grpkey), ":%s", grp->gr_name);
677 			pw_getconf(option, sizeof(option), grpkey, cipher);
678 		}
679 		if (*option == 0)
680 		        pw_getconf(option, sizeof(option), "default", cipher);
681 	}
682 
683 	next = option;
684 	now = strsep(&next, ",");
685 	if (strcmp(now, "old") == 0) {
686 		if (max < 3)
687 			return (0);
688 		to64(&salt[0], arc4random(), 2);
689 		salt[2] = '\0';
690 	} else if (strcmp(now, "newsalt") == 0) {
691 		rounds = atol(next);
692 		if (max < 10)
693 			return (0);
694 		/* Check rounds, 24 bit is max */
695 		if (rounds < 7250)
696 			rounds = 7250;
697 		else if (rounds > 0xffffff)
698 		        rounds = 0xffffff;
699 		salt[0] = _PASSWORD_EFMT1;
700 		to64(&salt[1], (u_int32_t)rounds, 4);
701 		to64(&salt[5], arc4random(), 4);
702 		salt[9] = '\0';
703 	} else if (strcmp(now, "md5") == 0) {
704 		if (max < 13)  /* $1$8salt$\0 */
705 			return (0);
706 		salt[0] = _PASSWORD_NONDES;
707 		salt[1] = '1';
708 		salt[2] = '$';
709 		to64(&salt[3], arc4random(), 4);
710 		to64(&salt[7], arc4random(), 4);
711 		salt[11] = '$';
712 		salt[12] = '\0';
713 	} else if (strcmp(now, "blowfish") == 0) {
714 		rounds = atoi(next);
715 		if (rounds < 4)
716 			rounds = 4;
717 		strlcpy(salt, bcrypt_gensalt(rounds), (size_t)max);
718 	} else {
719 		strlcpy(salt, ":", (size_t)max);
720 #if 0
721 		/* XXX pam_error()? */
722 		warnx("Unknown option %s.", now);
723 #endif
724 	}
725 
726 	return (1);
727 }
728