2 Unix SMB/CIFS implementation.
3 kerberos utility library
4 Copyright (C) Andrew Tridgell 2001
5 Copyright (C) Remus Koos 2001
6 Copyright (C) Nalin Dahyabhai 2004.
7 Copyright (C) Jeremy Allison 2004.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 #define LIBADS_CCACHE_NAME "MEMORY:libads"
31 we use a prompter to avoid a crash bug in the kerberos libs when
32 dealing with empty passwords
33 this prompter is just a string copy ...
35 static krb5_error_code
36 kerb_prompter(krb5_context ctx, void *data,
40 krb5_prompt prompts[])
42 if (num_prompts == 0) return 0;
44 memset(prompts[0].reply->data, '\0', prompts[0].reply->length);
45 if (prompts[0].reply->length > 0) {
47 strncpy(prompts[0].reply->data, data, prompts[0].reply->length-1);
48 prompts[0].reply->length = strlen(prompts[0].reply->data);
50 prompts[0].reply->length = 0;
57 simulate a kinit, putting the tgt in the given cache location. If cache_name == NULL
58 place in default cache location.
61 int kerberos_kinit_password(const char *principal,
65 const char *cache_name)
67 krb5_context ctx = NULL;
68 krb5_error_code code = 0;
69 krb5_ccache cc = NULL;
73 if ((code = krb5_init_context(&ctx)))
76 if (time_offset != 0) {
77 krb5_set_real_time(ctx, time(NULL) + time_offset, 0);
80 if ((code = krb5_cc_resolve(ctx, cache_name ?
81 cache_name : krb5_cc_default_name(ctx), &cc))) {
82 krb5_free_context(ctx);
86 if ((code = krb5_parse_name(ctx, principal, &me))) {
87 krb5_free_context(ctx);
91 if ((code = krb5_get_init_creds_password(ctx, &my_creds, me, password,
93 NULL, 0, NULL, NULL))) {
94 krb5_free_principal(ctx, me);
95 krb5_free_context(ctx);
99 if ((code = krb5_cc_initialize(ctx, cc, me))) {
100 krb5_free_cred_contents(ctx, &my_creds);
101 krb5_free_principal(ctx, me);
102 krb5_free_context(ctx);
106 if ((code = krb5_cc_store_cred(ctx, cc, &my_creds))) {
107 krb5_cc_close(ctx, cc);
108 krb5_free_cred_contents(ctx, &my_creds);
109 krb5_free_principal(ctx, me);
110 krb5_free_context(ctx);
115 *expire_time = (time_t) my_creds.times.endtime;
117 krb5_cc_close(ctx, cc);
118 krb5_free_cred_contents(ctx, &my_creds);
119 krb5_free_principal(ctx, me);
120 krb5_free_context(ctx);
127 /* run kinit to setup our ccache */
128 int ads_kinit_password(ADS_STRUCT *ads)
133 if (asprintf(&s, "%s@%s", ads->auth.user_name, ads->auth.realm) == -1) {
134 return KRB5_CC_NOMEM;
137 if (!ads->auth.password) {
138 return KRB5_LIBOS_CANTREADPWD;
141 ret = kerberos_kinit_password(s, ads->auth.password, ads->auth.time_offset,
142 &ads->auth.expire, NULL);
145 DEBUG(0,("kerberos_kinit_password %s failed: %s\n",
146 s, error_message(ret)));
152 int ads_kdestroy(const char *cc_name)
154 krb5_error_code code;
155 krb5_context ctx = NULL;
156 krb5_ccache cc = NULL;
158 if ((code = krb5_init_context (&ctx))) {
159 DEBUG(3, ("ads_kdestroy: kdb5_init_context failed: %s\n",
160 error_message(code)));
165 if ((code = krb5_cc_default(ctx, &cc))) {
166 krb5_free_context(ctx);
170 if ((code = krb5_cc_resolve(ctx, cc_name, &cc))) {
171 DEBUG(3, ("ads_kdestroy: krb5_cc_resolve failed: %s\n",
172 error_message(code)));
173 krb5_free_context(ctx);
178 if ((code = krb5_cc_destroy (ctx, cc))) {
179 DEBUG(3, ("ads_kdestroy: krb5_cc_destroy failed: %s\n",
180 error_message(code)));
183 krb5_free_context (ctx);
187 /************************************************************************
188 Routine to fetch the salting principal for a service. Active
189 Directory may use a non-obvious principal name to generate the salt
190 when it determines the key to use for encrypting tickets for a service,
191 and hopefully we detected that when we joined the domain.
192 ************************************************************************/
194 static char *kerberos_secrets_fetch_salting_principal(const char *service, int enctype)
199 asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, service, enctype);
203 ret = (char *)secrets_fetch(key, NULL);
208 /************************************************************************
209 Routine to get the salting principal for this service. Active
210 Directory may use a non-obvious principal name to generate the salt
211 when it determines the key to use for encrypting tickets for a service,
212 and hopefully we detected that when we joined the domain.
213 Caller must free if return is not null.
214 ************************************************************************/
216 krb5_principal kerberos_fetch_salt_princ_for_host_princ(krb5_context context,
217 krb5_principal host_princ,
220 char *unparsed_name = NULL, *salt_princ_s = NULL;
221 krb5_principal ret_princ = NULL;
223 if (krb5_unparse_name(context, host_princ, &unparsed_name) != 0) {
224 return (krb5_principal)NULL;
227 if ((salt_princ_s = kerberos_secrets_fetch_salting_principal(unparsed_name, enctype)) == NULL) {
228 krb5_free_unparsed_name(context, unparsed_name);
229 return (krb5_principal)NULL;
232 if (krb5_parse_name(context, salt_princ_s, &ret_princ) != 0) {
233 krb5_free_unparsed_name(context, unparsed_name);
234 SAFE_FREE(salt_princ_s);
235 return (krb5_principal)NULL;
237 krb5_free_unparsed_name(context, unparsed_name);
238 SAFE_FREE(salt_princ_s);
242 /************************************************************************
243 Routine to set the salting principal for this service. Active
244 Directory may use a non-obvious principal name to generate the salt
245 when it determines the key to use for encrypting tickets for a service,
246 and hopefully we detected that when we joined the domain.
247 Setting principal to NULL deletes this entry.
248 ************************************************************************/
250 BOOL kerberos_secrets_store_salting_principal(const char *service,
252 const char *principal)
256 krb5_context context = NULL;
257 krb5_principal princ = NULL;
258 char *princ_s = NULL;
259 char *unparsed_name = NULL;
261 krb5_init_context(&context);
265 if (strchr_m(service, '@')) {
266 asprintf(&princ_s, "%s", service);
268 asprintf(&princ_s, "%s@%s", service, lp_realm());
271 if (krb5_parse_name(context, princ_s, &princ) != 0) {
275 if (krb5_unparse_name(context, princ, &unparsed_name) != 0) {
279 asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, unparsed_name, enctype);
284 if ((principal != NULL) && (strlen(principal) > 0)) {
285 ret = secrets_store(key, principal, strlen(principal) + 1);
287 ret = secrets_delete(key);
296 krb5_free_unparsed_name(context, unparsed_name);
299 krb5_free_context(context);
305 /************************************************************************
306 Routine to get initial credentials as a service ticket for the local machine.
307 Returns a buffer initialized with krb5_mk_req_extended.
308 ************************************************************************/
310 static krb5_error_code get_service_ticket(krb5_context ctx,
312 const char *service_principal,
316 krb5_creds creds, *new_creds = NULL;
317 char *service_s = NULL;
318 char *machine_account = NULL, *password = NULL;
320 krb5_auth_context auth_context = NULL;
321 krb5_error_code err = 0;
323 asprintf(&machine_account, "%s$@%s", global_myname(), lp_realm());
324 if (machine_account == NULL) {
327 password = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
328 if (password == NULL) {
331 if ((err = kerberos_kinit_password(machine_account, password, 0, NULL, LIBADS_CCACHE_NAME)) != 0) {
332 DEBUG(0,("get_service_ticket: kerberos_kinit_password %s@%s failed: %s\n",
335 error_message(err)));
339 /* Ok - the above call has gotten a TGT. Now we need to get a service
340 ticket to ourselves. */
342 /* Set up the enctype and client and server principal fields for krb5_get_credentials. */
343 memset(&creds, '\0', sizeof(creds));
344 kerberos_set_creds_enctype(&creds, enctype);
346 if ((err = krb5_cc_get_principal(ctx, ccache, &creds.client))) {
347 DEBUG(3, ("get_service_ticket: krb5_cc_get_principal failed: %s\n",
348 error_message(err)));
352 if (strchr_m(service_principal, '@')) {
353 asprintf(&service_s, "%s", service_principal);
355 asprintf(&service_s, "%s@%s", service_principal, lp_realm());
358 if ((err = krb5_parse_name(ctx, service_s, &creds.server))) {
359 DEBUG(0,("get_service_ticket: krb5_parse_name %s failed: %s\n",
360 service_s, error_message(err)));
364 if ((err = krb5_get_credentials(ctx, 0, ccache, &creds, &new_creds))) {
365 DEBUG(5,("get_service_ticket: krb5_get_credentials for %s failed: %s\n",
366 service_s, error_message(err)));
370 memset(&in_data, '\0', sizeof(in_data));
371 if ((err = krb5_mk_req_extended(ctx, &auth_context, 0, &in_data,
372 new_creds, p_outbuf)) != 0) {
373 DEBUG(0,("get_service_ticket: krb5_mk_req_extended failed: %s\n",
374 error_message(err)));
381 krb5_auth_con_free(ctx, auth_context);
384 krb5_free_creds(ctx, new_creds);
387 krb5_free_principal(ctx, creds.server);
390 krb5_free_principal(ctx, creds.client);
393 SAFE_FREE(service_s);
395 SAFE_FREE(machine_account);
399 /************************************************************************
400 Check if the machine password can be used in conjunction with the salting_principal
401 to generate a key which will successfully decrypt the AP_REQ already
402 gotten as a message to the local machine.
403 ************************************************************************/
405 static BOOL verify_service_password(krb5_context ctx,
407 const char *salting_principal,
411 krb5_principal salting_kprinc = NULL;
412 krb5_ticket *ticket = NULL;
415 char *salting_s = NULL;
416 char *machine_account = NULL, *password = NULL;
417 krb5_auth_context auth_context = NULL;
420 memset(&passdata, '\0', sizeof(passdata));
421 memset(&key, '\0', sizeof(key));
423 asprintf(&machine_account, "%s$@%s", global_myname(), lp_realm());
424 if (machine_account == NULL) {
427 password = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
428 if (password == NULL) {
432 if (strchr_m(salting_principal, '@')) {
433 asprintf(&salting_s, "%s", salting_principal);
435 asprintf(&salting_s, "%s@%s", salting_principal, lp_realm());
438 if ((err = krb5_parse_name(ctx, salting_s, &salting_kprinc))) {
439 DEBUG(0,("verify_service_password: krb5_parse_name %s failed: %s\n",
440 salting_s, error_message(err)));
444 passdata.length = strlen(password);
445 passdata.data = (char*)password;
446 if ((err = create_kerberos_key_from_string_direct(ctx, salting_kprinc, &passdata, &key, enctype))) {
447 DEBUG(0,("verify_service_password: create_kerberos_key_from_string %d failed: %s\n",
448 enctype, error_message(err)));
452 if ((err = krb5_auth_con_init(ctx, &auth_context)) != 0) {
453 DEBUG(0,("verify_service_password: krb5_auth_con_init failed %s\n", error_message(err)));
457 if ((err = krb5_auth_con_setuseruserkey(ctx, auth_context, &key)) != 0) {
458 DEBUG(0,("verify_service_password: krb5_auth_con_setuseruserkey failed %s\n", error_message(err)));
462 if (!(err = krb5_rd_req(ctx, &auth_context, in_data, NULL, NULL, NULL, &ticket))) {
463 DEBUG(10,("verify_service_password: decrypted message with enctype %u salt %s!\n",
464 (unsigned int)enctype, salting_s));
470 memset(&passdata, 0, sizeof(passdata));
471 krb5_free_keyblock_contents(ctx, &key);
472 if (ticket != NULL) {
473 krb5_free_ticket(ctx, ticket);
475 if (salting_kprinc) {
476 krb5_free_principal(ctx, salting_kprinc);
478 SAFE_FREE(salting_s);
480 SAFE_FREE(machine_account);
484 /************************************************************************
486 * From the current draft of kerberos-clarifications:
488 * It is not possible to reliably generate a user's key given a pass
489 * phrase without contacting the KDC, since it will not be known
490 * whether alternate salt or parameter values are required.
492 * And because our server has a password, we have this exact problem. We
493 * make multiple guesses as to which principal name provides the salt which
496 ************************************************************************/
498 static void kerberos_derive_salting_principal_for_enctype(const char *service_principal,
501 krb5_enctype enctype,
502 krb5_enctype *enctypes)
504 char *salting_principals[3] = {NULL, NULL, NULL}, *second_principal = NULL;
505 krb5_error_code err = 0;
509 memset(&outbuf, '\0', sizeof(outbuf));
511 /* Check that the service_principal is useful. */
512 if ((service_principal == NULL) || (strlen(service_principal) == 0)) {
516 /* Generate our first guess -- the principal as-given. */
517 asprintf(&salting_principals[0], "%s", service_principal);
518 if ((salting_principals[0] == NULL) || (strlen(salting_principals[0]) == 0)) {
522 /* Generate our second guess -- the computer's principal, as Win2k3. */
523 asprintf(&second_principal, "host/%s.%s", global_myname(), lp_realm());
524 if (second_principal != NULL) {
525 strlower_m(second_principal);
526 asprintf(&salting_principals[1], "%s@%s", second_principal, lp_realm());
527 SAFE_FREE(second_principal);
529 if ((salting_principals[1] == NULL) || (strlen(salting_principals[1]) == 0)) {
533 /* Generate our third guess -- the computer's principal, as Win2k. */
534 asprintf(&second_principal, "HOST/%s", global_myname());
535 if (second_principal != NULL) {
536 strlower_m(second_principal + 5);
537 asprintf(&salting_principals[2], "%s@%s",
538 second_principal, lp_realm());
539 SAFE_FREE(second_principal);
541 if ((salting_principals[2] == NULL) || (strlen(salting_principals[2]) == 0)) {
545 /* Get a service ticket for ourselves into our memory ccache. */
546 /* This will commonly fail if there is no principal by that name (and we're trying
547 many names). So don't print a debug 0 error. */
549 if ((err = get_service_ticket(ctx, ccache, service_principal, enctype, &outbuf)) != 0) {
550 DEBUG(3, ("verify_service_password: get_service_ticket failed: %s\n",
551 error_message(err)));
555 /* At this point we have a message to ourselves, salted only the KDC knows how. We
556 have to work out what that salting is. */
558 /* Try and find the correct salting principal. */
559 for (i = 0; i < sizeof(salting_principals) / sizeof(salting_principals[i]); i++) {
560 if (verify_service_password(ctx, enctype, salting_principals[i], &outbuf)) {
565 /* If we failed to get a match, return. */
566 if (i >= sizeof(salting_principals) / sizeof(salting_principals[i])) {
570 /* If we succeeded, store the principal for use for all enctypes which
571 * share the same cipher and string-to-key function. Doing this here
572 * allows servers which just pass a keytab to krb5_rd_req() to work
574 for (j = 0; enctypes[j] != 0; j++) {
575 if (enctype != enctypes[j]) {
576 /* If this enctype isn't compatible with the one which
577 * we used, skip it. */
579 if (!kerberos_compatible_enctypes(ctx, enctypes[j], enctype))
582 /* If the principal which gives us the proper salt is the one
583 * which we would normally guess, don't bother noting anything
584 * in the secrets tdb. */
585 if (strcmp(service_principal, salting_principals[i]) != 0) {
586 kerberos_secrets_store_salting_principal(service_principal,
588 salting_principals[i]);
594 kerberos_free_data_contents(ctx, &outbuf);
595 SAFE_FREE(salting_principals[0]);
596 SAFE_FREE(salting_principals[1]);
597 SAFE_FREE(salting_principals[2]);
598 SAFE_FREE(second_principal);
601 /************************************************************************
602 Go through all the possible enctypes for this principal.
603 ************************************************************************/
605 void kerberos_derive_salting_principal(krb5_context context,
607 krb5_enctype *enctypes,
608 char *service_principal)
611 BOOL free_ccache = False;
613 if (ccache == NULL) {
615 if ((ret = krb5_cc_resolve(context, LIBADS_CCACHE_NAME, &ccache)) != 0) {
616 DEBUG(0, ("kerberos_derive_salting_principal: krb5_cc_resolve for %s failed: %s\n",
617 LIBADS_CCACHE_NAME, error_message(ret)));
623 /* Try for each enctype separately, because the rules are
624 * different for different enctypes. */
625 for (i = 0; enctypes[i] != 0; i++) {
626 /* Delete secrets entry first. */
627 kerberos_secrets_store_salting_principal(service_principal, 0, NULL);
628 #ifdef ENCTYPE_ARCFOUR_HMAC
629 if (enctypes[i] == ENCTYPE_ARCFOUR_HMAC) {
630 /* Of course this'll always work, so just save
631 * ourselves the effort. */
635 /* Try to figure out what's going on with this
637 kerberos_derive_salting_principal_for_enctype(service_principal,
644 if (free_ccache && ccache) {
645 krb5_cc_close(context, ccache);
649 /************************************************************************
650 Core function to try and determine what salt is being used for any keytab
652 ************************************************************************/
654 BOOL kerberos_derive_cifs_salting_principals(void)
657 char *service = NULL;
658 krb5_context context = NULL;
659 krb5_enctype *enctypes = NULL;
660 krb5_ccache ccache = NULL;
661 krb5_error_code ret = 0;
664 initialize_krb5_error_table();
665 if ((ret = krb5_init_context(&context)) != 0) {
666 DEBUG(1,("kerberos_derive_cifs_salting_principals: krb5_init_context failed. %s\n",
667 error_message(ret)));
670 if ((ret = get_kerberos_allowed_etypes(context, &enctypes)) != 0) {
671 DEBUG(1,("kerberos_derive_cifs_salting_principals: get_kerberos_allowed_etypes failed. %s\n",
672 error_message(ret)));
676 if ((ret = krb5_cc_resolve(context, LIBADS_CCACHE_NAME, &ccache)) != 0) {
677 DEBUG(3, ("get_service_ticket: krb5_cc_resolve for %s failed: %s\n",
678 LIBADS_CCACHE_NAME, error_message(ret)));
682 if (asprintf(&service, "%s$", global_myname()) != -1) {
684 kerberos_derive_salting_principal(context, ccache, enctypes, service);
687 if (asprintf(&service, "cifs/%s", global_myname()) != -1) {
689 kerberos_derive_salting_principal(context, ccache, enctypes, service);
692 if (asprintf(&service, "host/%s", global_myname()) != -1) {
694 kerberos_derive_salting_principal(context, ccache, enctypes, service);
697 if (asprintf(&service, "cifs/%s.%s", global_myname(), lp_realm()) != -1) {
699 kerberos_derive_salting_principal(context, ccache, enctypes, service);
702 if (asprintf(&service, "host/%s.%s", global_myname(), lp_realm()) != -1) {
704 kerberos_derive_salting_principal(context, ccache, enctypes, service);
707 name_to_fqdn(my_fqdn, global_myname());
708 if (asprintf(&service, "cifs/%s", my_fqdn) != -1) {
710 kerberos_derive_salting_principal(context, ccache, enctypes, service);
713 if (asprintf(&service, "host/%s", my_fqdn) != -1) {
715 kerberos_derive_salting_principal(context, ccache, enctypes, service);
723 free_kerberos_etypes(context, enctypes);
726 krb5_cc_destroy(context, ccache);
729 krb5_free_context(context);