xref: /illumos-gate/usr/src/lib/pam_modules/krb5/krb5_authenticate.c (revision 4fceebdf03eeac0d7c58a4f70cc19b00a8c40a73)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <security/pam_appl.h>
29 #include <security/pam_modules.h>
30 #include <security/pam_impl.h>
31 #include <string.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <sys/types.h>
35 #include <sys/stat.h>
36 #include <pwd.h>
37 #include <syslog.h>
38 #include <libintl.h>
39 #include <k5-int.h>
40 #include "profile/prof_int.h"
41 #include <netdb.h>
42 #include <ctype.h>
43 #include "utils.h"
44 #include "krb5_repository.h"
45 
46 #define	KRB5_DEFAULT_OPTIONS 0
47 
48 int forwardable_flag = 0;
49 int renewable_flag = 0;
50 int proxiable_flag = 0;
51 int no_address_flag = 0;
52 profile_options_boolean config_option[] = {
53 	{ "forwardable", &forwardable_flag, 0 },
54 	{ "renewable",  &renewable_flag, 0 },
55 	{ "proxiable", &proxiable_flag, 0 },
56 	{ "no_addresses", &no_address_flag, 0 },
57 	{ NULL, NULL, 0 }
58 };
59 char *renew_timeval;
60 char *life_timeval;
61 profile_option_strings config_times[] = {
62 	{ "max_life", &life_timeval, 0 },
63 	{ "max_renewable_life",  &renew_timeval, 0 },
64 	{ NULL, NULL, 0 }
65 };
66 char *realmdef[] = { "realms", NULL, NULL, NULL };
67 char *appdef[] = { "appdefaults", "kinit", NULL };
68 
69 #define	krb_realm (*(realmdef + 1))
70 
71 int	attempt_krb5_auth(krb5_module_data_t *, char *, char **, boolean_t);
72 void	krb5_cleanup(pam_handle_t *, void *, int);
73 
74 extern errcode_t profile_get_options_boolean();
75 extern errcode_t profile_get_options_string();
76 extern int krb5_verifypw(char *, char *, int);
77 extern krb5_error_code krb5_verify_init_creds(krb5_context,
78 		krb5_creds *, krb5_principal, krb5_keytab, krb5_ccache *,
79 		krb5_verify_init_creds_opt *);
80 
81 /*
82  * pam_sm_authenticate		- Authenticate user
83  */
84 int
85 pam_sm_authenticate(
86 	pam_handle_t		*pamh,
87 	int 			flags,
88 	int			argc,
89 	const char		**argv)
90 {
91 	char			*user = NULL;
92 	int			err;
93 	int			result = PAM_AUTH_ERR;
94 	/* pam.conf options */
95 	int			debug = 0;
96 	int			warn = 1;
97 	/* return an error on password expire */
98 	int			err_on_exp = 0;
99 	int			i;
100 	char			*password = NULL;
101 	uid_t			pw_uid;
102 	krb5_module_data_t	*kmd = NULL;
103 	krb5_repository_data_t  *krb5_data = NULL;
104 	pam_repository_t	*rep_data = NULL;
105 
106 	for (i = 0; i < argc; i++) {
107 		if (strcmp(argv[i], "debug") == 0) {
108 			debug = 1;
109 		} else if (strcmp(argv[i], "nowarn") == 0) {
110 			warn = 0;
111 		} else if (strcmp(argv[i], "err_on_exp") == 0) {
112 			err_on_exp = 1;
113 		} else {
114 			__pam_log(LOG_AUTH | LOG_ERR,
115 				"PAM-KRB5 (auth) unrecognized option %s",
116 				argv[i]);
117 		}
118 	}
119 	if (flags & PAM_SILENT) warn = 0;
120 
121 	if (debug)
122 		__pam_log(LOG_AUTH | LOG_DEBUG,
123 		    "PAM-KRB5 (auth): pam_sm_authenticate flags=%d",
124 		    flags);
125 
126 	(void) pam_get_item(pamh, PAM_USER, (void**) &user);
127 
128 	if (user == NULL || *user == '\0') {
129 		if (debug)
130 			__pam_log(LOG_AUTH | LOG_DEBUG,
131 				"PAM-KRB5 (auth): user empty or null");
132 		return (PAM_USER_UNKNOWN);
133 	}
134 
135 	/* make sure a password entry exists for this user */
136 	if (!get_pw_uid(user, &pw_uid))
137 		return (PAM_USER_UNKNOWN);
138 
139 	/*
140 	 * pam_get_data could fail if we are being called for the first time
141 	 * or if the module is not found, PAM_NO_MODULE_DATA is not an error
142 	 */
143 	err = pam_get_data(pamh, KRB5_DATA, (const void**)&kmd);
144 	if (!(err == PAM_SUCCESS || err == PAM_NO_MODULE_DATA))
145 		return (PAM_SYSTEM_ERR);
146 
147 	if (kmd == NULL) {
148 		kmd = calloc(1, sizeof (krb5_module_data_t));
149 		if (kmd == NULL) {
150 			result = PAM_BUF_ERR;
151 			goto out;
152 		}
153 
154 		err = pam_set_data(pamh, KRB5_DATA, kmd, &krb5_cleanup);
155 		if (err != PAM_SUCCESS) {
156 			free(kmd);
157 			result = err;
158 			goto out;
159 		}
160 	}
161 
162 	if (!kmd->env) {
163 		char buffer[512];
164 
165 		if (snprintf(buffer, sizeof (buffer),
166 			    "%s=FILE:/tmp/krb5cc_%d",
167 			    KRB5_ENV_CCNAME, (int)pw_uid) >= sizeof (buffer)) {
168 			result = PAM_SYSTEM_ERR;
169 			goto out;
170 		}
171 
172 		/* we MUST copy this to the heap for the putenv to work! */
173 		kmd->env = strdup(buffer);
174 		if (!kmd->env) {
175 			result = PAM_BUF_ERR;
176 			goto out;
177 		} else {
178 			if (putenv(kmd->env)) {
179 				result = PAM_SYSTEM_ERR;
180 				goto out;
181 			}
182 		}
183 	}
184 
185 	if ((kmd->user = strdup(user)) == NULL) {
186 		result = PAM_BUF_ERR;
187 		goto out;
188 	}
189 
190 	kmd->auth_status = PAM_AUTH_ERR;
191 	kmd->debug = debug;
192 	kmd->warn = warn;
193 	kmd->err_on_exp = err_on_exp;
194 	kmd->ccache = NULL;
195 	kmd->kcontext = NULL;
196 	kmd->password = NULL;
197 	kmd->age_status = PAM_SUCCESS;
198 	(void) memset((char *)&kmd->initcreds, 0, sizeof (krb5_creds));
199 
200 	/*
201 	 * For apps that already did krb5 auth exchange...
202 	 * Now that we've created the kmd structure, we can
203 	 * return SUCCESS.  'kmd' may be needed later by other
204 	 * PAM functions, thats why we wait until this point to
205 	 * return.
206 	 */
207 	(void) pam_get_item(pamh, PAM_REPOSITORY, (void **)&rep_data);
208 
209 	if (rep_data != NULL) {
210 		if (strcmp(rep_data->type, KRB5_REPOSITORY_NAME) != 0) {
211 			if (debug)
212 				__pam_log(LOG_AUTH | LOG_DEBUG,
213 					"PAM-KRB5 (auth): wrong"
214 					"repository found (%s), returning "
215 					"PAM_IGNORE", rep_data->type);
216 			return (PAM_IGNORE);
217 		}
218 		if (rep_data->scope_len == sizeof (krb5_repository_data_t)) {
219 			krb5_data = (krb5_repository_data_t *)rep_data->scope;
220 
221 			if (krb5_data->flags ==
222 				SUNW_PAM_KRB5_ALREADY_AUTHENTICATED &&
223 				krb5_data->principal != NULL &&
224 				strlen(krb5_data->principal)) {
225 				if (debug)
226 					__pam_log(LOG_AUTH | LOG_DEBUG,
227 						"PAM-KRB5 (auth): Principal "
228 						"%s already authenticated",
229 						krb5_data->principal);
230 				kmd->auth_status = PAM_SUCCESS;
231 				return (PAM_SUCCESS);
232 			}
233 		}
234 	}
235 
236 	/*
237 	 * if root key exists in the keytab, it's a random key so no
238 	 * need to prompt for pw and we just return IGNORE.
239 	 *
240 	 * note we don't need to force a prompt for pw as authtok_get
241 	 * is required to be stacked above this module.
242 	 */
243 	if ((strcmp(user, ROOT_UNAME) == 0) &&
244 	    key_in_keytab(user, debug)) {
245 		if (debug)
246 			__pam_log(LOG_AUTH | LOG_DEBUG,
247 			    "PAM-KRB5 (auth): "
248 			    "key for '%s' in keytab, returning IGNORE", user);
249 		result = PAM_IGNORE;
250 		goto out;
251 	}
252 
253 	(void) pam_get_item(pamh, PAM_AUTHTOK, (void **)&password);
254 
255 	result = attempt_krb5_auth(kmd, user, &password, 1);
256 
257 out:
258 	if (kmd) {
259 		if (debug)
260 			__pam_log(LOG_AUTH | LOG_DEBUG,
261 			    "PAM-KRB5 (auth): pam_sm_auth finalize"
262 			    " ccname env, result =%d, env ='%s',"
263 			    " age = %d, status = %d",
264 			    result, kmd->env ? kmd->env : "<null>",
265 			    kmd->age_status, kmd->auth_status);
266 
267 		if (kmd->env &&
268 		    !(kmd->age_status == PAM_NEW_AUTHTOK_REQD &&
269 			    kmd->auth_status == PAM_SUCCESS)) {
270 
271 
272 			if (result == PAM_SUCCESS) {
273 				/*
274 				 * Put ccname into the pamh so that login
275 				 * apps can pick this up when they run
276 				 * pam_getenvlist().
277 				 */
278 				if ((result = pam_putenv(pamh, kmd->env))
279 				    != PAM_SUCCESS) {
280 					/* should not happen but... */
281 					__pam_log(LOG_AUTH | LOG_ERR,
282 					    "PAM-KRB5 (auth):"
283 					    " pam_putenv failed: result: %d",
284 					    result);
285 					goto cleanupccname;
286 				}
287 			} else {
288 			cleanupccname:
289 				/* for lack of a Solaris unputenv() */
290 				krb5_unsetenv(KRB5_ENV_CCNAME);
291 				free(kmd->env);
292 				kmd->env = NULL;
293 			}
294 		}
295 		kmd->auth_status = result;
296 	}
297 
298 	if (debug)
299 		__pam_log(LOG_AUTH | LOG_DEBUG,
300 		    "PAM-KRB5 (auth): end: %s", pam_strerror(pamh, result));
301 
302 	return (result);
303 }
304 
305 int
306 attempt_krb5_auth(
307 	krb5_module_data_t	*kmd,
308 	char		*user,
309 	char		**krb5_pass,
310 	boolean_t	verify_tik)
311 {
312 	krb5_principal	me = NULL;
313 	krb5_principal	server = NULL;
314 	krb5_creds	*my_creds;
315 	krb5_timestamp	now;
316 	krb5_error_code	code = 0;
317 	char		kuser[2*MAXHOSTNAMELEN];
318 	krb5_deltat	lifetime;
319 	krb5_deltat	rlife;
320 	krb5_deltat	krb5_max_duration;
321 	int		options = KRB5_DEFAULT_OPTIONS;
322 	krb5_data tgtname = {
323 		0,
324 		KRB5_TGS_NAME_SIZE,
325 		KRB5_TGS_NAME
326 	};
327 	krb5_get_init_creds_opt opts;
328 	/*
329 	 * "result" should not be assigned PAM_SUCCESS unless
330 	 * authentication has succeeded and there are no other errors.
331 	 *
332 	 * "code" is sometimes used for PAM codes, sometimes for krb5
333 	 * codes.  Be careful.
334 	 */
335 	int result = PAM_AUTH_ERR;
336 
337 	if (kmd->debug)
338 		__pam_log(LOG_AUTH | LOG_DEBUG,
339 		    "PAM-KRB5 (auth): attempt_krb5_auth: start: user='%s'",
340 		    user ? user : "<null>");
341 
342 	krb5_get_init_creds_opt_init(&opts);
343 
344 	/* need to free context with krb5_free_context */
345 	if (code = krb5_init_context(&kmd->kcontext)) {
346 		__pam_log(LOG_AUTH | LOG_ERR,
347 			"PAM-KRB5 (auth): Error initializing "
348 			"krb5: %s",
349 			error_message(code));
350 		return (PAM_SYSTEM_ERR);
351 	}
352 
353 	if ((code = get_kmd_kuser(kmd->kcontext, (const char *)user, kuser,
354 		2*MAXHOSTNAMELEN)) != 0) {
355 		/* get_kmd_kuser returns proper PAM error statuses */
356 		return (code);
357 	}
358 
359 	if ((code = krb5_parse_name(kmd->kcontext, kuser, &me)) != 0) {
360 		krb5_free_context(kmd->kcontext);
361 		kmd->kcontext = NULL;
362 		return (PAM_SYSTEM_ERR);
363 	}
364 
365 	/* call krb5_free_cred_contents() on error */
366 	my_creds = &kmd->initcreds;
367 
368 	if ((code =
369 	    krb5_copy_principal(kmd->kcontext, me, &my_creds->client))) {
370 		result = PAM_SYSTEM_ERR;
371 		goto out_err;
372 	}
373 
374 	if (code = krb5_build_principal_ext(kmd->kcontext, &server,
375 			    krb5_princ_realm(kmd->kcontext, me)->length,
376 			    krb5_princ_realm(kmd->kcontext, me)->data,
377 			    tgtname.length, tgtname.data,
378 			    krb5_princ_realm(kmd->kcontext, me)->length,
379 			    krb5_princ_realm(kmd->kcontext, me)->data, 0)) {
380 		__pam_log(LOG_AUTH | LOG_ERR,
381 			"PAM-KRB5 (auth): attempt_krb5_auth: "
382 			"krb5_build_princ_ext failed: %s",
383 			error_message(code));
384 		result = PAM_SYSTEM_ERR;
385 		goto out;
386 	}
387 
388 	if (code = krb5_copy_principal(kmd->kcontext, server,
389 				&my_creds->server)) {
390 		result = PAM_SYSTEM_ERR;
391 		goto out_err;
392 	}
393 
394 	if (code = krb5_timeofday(kmd->kcontext, &now)) {
395 		__pam_log(LOG_AUTH | LOG_ERR,
396 			"PAM-KRB5 (auth): attempt_krb5_auth: "
397 			"krb5_timeofday failed: %s",
398 			error_message(code));
399 		result = PAM_SYSTEM_ERR;
400 		goto out;
401 	}
402 
403 	/*
404 	 * set the values for lifetime and rlife to be the maximum
405 	 * possible
406 	 */
407 	krb5_max_duration = KRB5_KDB_EXPIRATION - now - 60*60;
408 	lifetime = krb5_max_duration;
409 	rlife = krb5_max_duration;
410 
411 	/*
412 	 * Let us get the values for various options
413 	 * from Kerberos configuration file
414 	 */
415 
416 	krb_realm = krb5_princ_realm(kmd->kcontext, me)->data;
417 	profile_get_options_boolean(kmd->kcontext->profile,
418 				    realmdef, config_option);
419 	profile_get_options_boolean(kmd->kcontext->profile,
420 				    appdef, config_option);
421 	profile_get_options_string(kmd->kcontext->profile,
422 				realmdef, config_times);
423 	profile_get_options_string(kmd->kcontext->profile,
424 				appdef, config_times);
425 
426 	if (renew_timeval) {
427 		code = krb5_string_to_deltat(renew_timeval, &rlife);
428 		if (code != 0 || rlife == 0 || rlife > krb5_max_duration) {
429 			__pam_log(LOG_AUTH | LOG_ERR,
430 				    "PAM-KRB5 (auth): Bad max_renewable_life "
431 				    " value '%s' in Kerberos config file",
432 			    renew_timeval);
433 			result = PAM_SYSTEM_ERR;
434 			goto out;
435 		}
436 	}
437 	if (life_timeval) {
438 		code = krb5_string_to_deltat(life_timeval, &lifetime);
439 		if (code != 0 || lifetime == 0 ||
440 		    lifetime > krb5_max_duration) {
441 			__pam_log(LOG_AUTH | LOG_ERR,
442 				"lifetime value '%s' in Kerberos config file",
443 			    life_timeval);
444 			result = PAM_SYSTEM_ERR;
445 			goto out;
446 		}
447 	}
448 	/*  start timer when request gets to KDC */
449 	my_creds->times.starttime = 0;
450 	my_creds->times.endtime = now + lifetime;
451 
452 	if (options & KDC_OPT_RENEWABLE) {
453 		my_creds->times.renew_till = now + rlife;
454 	} else
455 		my_creds->times.renew_till = 0;
456 
457 	krb5_get_init_creds_opt_set_tkt_life(&opts, lifetime);
458 
459 	if (proxiable_flag) { 		/* Set in config file */
460 		if (kmd->debug)
461 			__pam_log(LOG_AUTH | LOG_DEBUG,
462 				"PAM-KRB5 (auth): Proxiable tickets "
463 				"requested");
464 		krb5_get_init_creds_opt_set_proxiable(&opts, TRUE);
465 	}
466 	if (forwardable_flag) {
467 		if (kmd->debug)
468 			__pam_log(LOG_AUTH | LOG_DEBUG,
469 				"PAM-KRB5 (auth): Forwardable tickets "
470 				"requested");
471 		krb5_get_init_creds_opt_set_forwardable(&opts, TRUE);
472 	}
473 	if (renewable_flag) {
474 		if (kmd->debug)
475 			__pam_log(LOG_AUTH | LOG_DEBUG,
476 				"PAM-KRB5 (auth): Renewable tickets "
477 				"requested");
478 		krb5_get_init_creds_opt_set_renew_life(&opts, rlife);
479 	}
480 	if (no_address_flag) {
481 		if (kmd->debug)
482 			__pam_log(LOG_AUTH | LOG_DEBUG,
483 				"PAM-KRB5 (auth): Addressless tickets "
484 				"requested");
485 		krb5_get_init_creds_opt_set_address_list(&opts, NULL);
486 	}
487 
488 	/*
489 	 * mech_krb5 interprets empty passwords as NULL passwords
490 	 * and tries to read a password from stdin. Since we are in
491 	 * pam this is bad and should not be allowed.
492 	 */
493 	if (*krb5_pass == NULL || strlen(*krb5_pass) == 0) {
494 		code = KRB5KRB_AP_ERR_BAD_INTEGRITY;
495 	} else {
496 		code = krb5_get_init_creds_password(kmd->kcontext,
497 				my_creds,
498 				me,
499 				*krb5_pass,	/* clear text passwd */
500 				NULL,		/* prompter */
501 				NULL,		/* data */
502 				0,		/* start time */
503 				NULL,		/* defaults to krbtgt@REALM */
504 				&opts);
505 	}
506 
507 	if (kmd->debug)
508 		__pam_log(LOG_AUTH | LOG_DEBUG,
509 		    "PAM-KRB5 (auth): attempt_krb5_auth: "
510 		    "krb5_get_init_creds_password returns: %s",
511 		    code == 0 ? "SUCCESS" : error_message(code));
512 
513 	switch (code) {
514 	case 0:
515 		/* got a tgt, let's verify it */
516 		if (verify_tik) {
517 			krb5_verify_init_creds_opt vopts;
518 
519 			krb5_principal sp = NULL;
520 			char kt_name[MAX_KEYTAB_NAME_LEN];
521 			char *fqdn;
522 
523 			krb5_verify_init_creds_opt_init(&vopts);
524 
525 			code = krb5_verify_init_creds(kmd->kcontext,
526 				my_creds,
527 				NULL,	/* defaults to host/localhost@REALM */
528 				NULL,
529 				NULL,
530 				&vopts);
531 
532 			if (code) {
533 				result = PAM_SYSTEM_ERR;
534 
535 				/*
536 				 * Give a better error message when the
537 				 * keytable entry isn't found or the keytab
538 				 * file cannot be found.
539 				 */
540 				if (krb5_sname_to_principal(kmd->kcontext, NULL,
541 						NULL, KRB5_NT_SRV_HST, &sp))
542 					fqdn = "<fqdn>";
543 				else
544 					fqdn = sp->data[1].data;
545 
546 				if (krb5_kt_default_name(kmd->kcontext, kt_name,
547 							sizeof (kt_name)))
548 					(void) strncpy(kt_name,
549 						"default keytab",
550 						sizeof (kt_name));
551 
552 				switch (code) {
553 				case KRB5_KT_NOTFOUND:
554 					__pam_log(LOG_AUTH | LOG_ERR,
555 						"PAM-KRB5 (auth): "
556 						"krb5_verify_init_creds failed:"
557 						" Key table entry \"host/%s\""
558 						" not found in %s",
559 						fqdn, kt_name);
560 					break;
561 				case ENOENT:
562 					__pam_log(LOG_AUTH | LOG_ERR,
563 						"PAM-KRB5 (auth): "
564 						"krb5_verify_init_creds failed:"
565 						" Keytab file \"%s\""
566 						" does not exist.\n",
567 						kt_name);
568 					break;
569 				default:
570 					__pam_log(LOG_AUTH | LOG_ERR,
571 						"PAM-KRB5 (auth): "
572 						"krb5_verify_init_creds failed:"
573 						" %s",
574 						error_message(code));
575 					break;
576 				}
577 
578 				if (sp)
579 					krb5_free_principal(kmd->kcontext, sp);
580 			}
581 		}
582 		break;
583 
584 	case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
585 		/*
586 		 * Since this principal is not part of the local
587 		 * Kerberos realm, we just return PAM_USER_UNKNOWN.
588 		 */
589 		result = PAM_USER_UNKNOWN;
590 
591 		if (kmd->debug)
592 			__pam_log(LOG_AUTH | LOG_DEBUG,
593 				"PAM-KRB5 (auth): attempt_krb5_auth:"
594 				" User is not part of the local Kerberos"
595 				" realm: %s", error_message(code));
596 		break;
597 
598 	case KRB5KDC_ERR_PREAUTH_FAILED:
599 	case KRB5KRB_AP_ERR_BAD_INTEGRITY:
600 		/*
601 		 * We could be trying the password from a previous
602 		 * pam authentication module, but we don't want to
603 		 * generate an error if the unix password is different
604 		 * than the Kerberos password...
605 		 */
606 		break;
607 
608 	case KRB5KDC_ERR_KEY_EXP:
609 		if (!kmd->err_on_exp) {
610 			/*
611 			 * Request a tik for changepw service
612 			 * and it will tell us if pw is good or not.
613 			 */
614 			code = krb5_verifypw(kuser, *krb5_pass, kmd->debug);
615 
616 			if (kmd->debug)
617 				__pam_log(LOG_AUTH | LOG_DEBUG,
618 				    "PAM-KRB5 (auth): attempt_krb5_auth: "
619 				    "verifypw %d", code);
620 
621 			if (code == 0) {
622 				/* pw is good, set age status for acct_mgmt */
623 				kmd->age_status = PAM_NEW_AUTHTOK_REQD;
624 			}
625 		}
626 		break;
627 
628 	default:
629 		result = PAM_SYSTEM_ERR;
630 		if (kmd->debug)
631 			__pam_log(LOG_AUTH | LOG_DEBUG,
632 				"PAM-KRB5 (auth): error %d - %s",
633 				code, error_message(code));
634 		break;
635 	}
636 
637 	if (code == 0) {
638 		/*
639 		 * success for the entered pw
640 		 *
641 		 * we can't rely on the pw in PAM_AUTHTOK
642 		 * to be the (correct) krb5 one so
643 		 * store krb5 pw in module data for
644 		 * use in acct_mgmt
645 		 */
646 		if (!(kmd->password = strdup(*krb5_pass))) {
647 			__pam_log(LOG_AUTH | LOG_ERR, "Cannot strdup password");
648 			result = PAM_BUF_ERR;
649 			goto out_err;
650 		}
651 		result = PAM_SUCCESS;
652 		goto out;
653 	}
654 
655 out_err:
656 	/* jump (or reach) here if error and cred cache has been init */
657 
658 	if (kmd->debug)
659 		__pam_log(LOG_AUTH | LOG_DEBUG,
660 		    "PAM-KRB5 (auth): clearing initcreds in "
661 		    "pam_authenticate()");
662 
663 	krb5_free_cred_contents(kmd->kcontext, &kmd->initcreds);
664 	(void) memset((char *)&kmd->initcreds, 0, sizeof (krb5_creds));
665 
666 out:
667 	if (server)
668 		krb5_free_principal(kmd->kcontext, server);
669 	if (me)
670 		krb5_free_principal(kmd->kcontext, me);
671 	if (kmd->kcontext) {
672 		krb5_free_context(kmd->kcontext);
673 		kmd->kcontext = NULL;
674 	}
675 
676 	if (kmd->debug)
677 		__pam_log(LOG_AUTH | LOG_DEBUG,
678 		    "PAM-KRB5 (auth): attempt_krb5_auth returning %d",
679 		    result);
680 
681 	return (kmd->auth_status = result);
682 }
683 
684 /*ARGSUSED*/
685 void
686 krb5_cleanup(pam_handle_t *pamh, void *data, int pam_status)
687 {
688 	krb5_module_data_t *kmd = (krb5_module_data_t *)data;
689 
690 	if (kmd == NULL)
691 		return;
692 
693 	if (kmd->debug) {
694 		__pam_log(LOG_AUTH | LOG_DEBUG,
695 			    "PAM-KRB5 (auth): krb5_cleanup auth_status = %d",
696 		    kmd->auth_status);
697 	}
698 
699 	/*
700 	 * if pam_status is PAM_SUCCESS, clean up based on value in
701 	 * auth_status, otherwise just purge the context
702 	 */
703 	if ((pam_status == PAM_SUCCESS) &&
704 	    (kmd->auth_status == PAM_SUCCESS) && kmd->ccache)
705 		krb5_cc_close(kmd->kcontext, kmd->ccache);
706 
707 	if (kmd->password) {
708 		(void) memset(kmd->password, 0, strlen(kmd->password));
709 		free(kmd->password);
710 	}
711 
712 	if (kmd->user != NULL)
713 		free(kmd->user);
714 
715 	if ((pam_status != PAM_SUCCESS) ||
716 	    (kmd->auth_status != PAM_SUCCESS)) {
717 		krb5_free_cred_contents(kmd->kcontext, &kmd->initcreds);
718 		(void) memset((char *)&kmd->initcreds, 0, sizeof (krb5_creds));
719 	}
720 
721 	free(kmd);
722 }
723