s3:winbindd: Fix a brown paper bag bug in wbinfo -t ...
[Samba.git] / source3 / libads / kerberos_verify.c
blobbf9bca63111f507656791e683d99dd56bbfa8ed6
1 /*
2 Unix SMB/CIFS implementation.
3 kerberos utility library
4 Copyright (C) Andrew Tridgell 2001
5 Copyright (C) Remus Koos 2001
6 Copyright (C) Luke Howard 2003
7 Copyright (C) Guenther Deschner 2003, 2005
8 Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
9 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
10 Copyright (C) Jeremy Allison 2007
12 This program is free software; you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation; either version 3 of the License, or
15 (at your option) any later version.
17 This program is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with this program. If not, see <http://www.gnu.org/licenses/>.
26 #include "includes.h"
27 #include "smb_krb5.h"
29 #ifdef HAVE_KRB5
31 #if !defined(HAVE_KRB5_PRINC_COMPONENT)
32 const krb5_data *krb5_princ_component(krb5_context, krb5_principal, int );
33 #endif
35 static bool ads_dedicated_keytab_verify_ticket(krb5_context context,
36 krb5_auth_context auth_context,
37 const DATA_BLOB *ticket,
38 krb5_ticket **pp_tkt,
39 krb5_keyblock **keyblock,
40 krb5_error_code *perr)
42 krb5_error_code ret = 0;
43 bool auth_ok = false;
44 krb5_keytab keytab = NULL;
45 krb5_keytab_entry kt_entry;
46 krb5_ticket *dec_ticket = NULL;
48 krb5_data packet;
49 krb5_kvno kvno = 0;
50 krb5_enctype enctype;
52 *pp_tkt = NULL;
53 *keyblock = NULL;
54 *perr = 0;
56 ZERO_STRUCT(kt_entry);
58 ret = smb_krb5_open_keytab(context, lp_dedicated_keytab_file(), true,
59 &keytab);
60 if (ret) {
61 DEBUG(1, ("smb_krb5_open_keytab failed (%s)\n",
62 error_message(ret)));
63 goto out;
66 packet.length = ticket->length;
67 packet.data = (char *)ticket->data;
69 ret = krb5_rd_req(context, &auth_context, &packet, NULL, keytab,
70 NULL, &dec_ticket);
71 if (ret) {
72 DEBUG(0, ("krb5_rd_req failed (%s)\n", error_message(ret)));
73 goto out;
76 #ifdef HAVE_ETYPE_IN_ENCRYPTEDDATA /* Heimdal */
77 enctype = dec_ticket->ticket.key.keytype;
78 #else /* MIT */
79 enctype = dec_ticket->enc_part.enctype;
80 kvno = dec_ticket->enc_part.kvno;
81 #endif
83 /* Get the key for checking the pac signature */
84 ret = krb5_kt_get_entry(context, keytab, dec_ticket->server,
85 kvno, enctype, &kt_entry);
86 if (ret) {
87 DEBUG(0, ("krb5_kt_get_entry failed (%s)\n",
88 error_message(ret)));
89 goto out;
92 ret = krb5_copy_keyblock(context, KRB5_KT_KEY(&kt_entry), keyblock);
93 smb_krb5_kt_free_entry(context, &kt_entry);
95 if (ret) {
96 DEBUG(0, ("failed to copy key: %s\n",
97 error_message(ret)));
98 goto out;
101 auth_ok = true;
102 *pp_tkt = dec_ticket;
103 dec_ticket = NULL;
105 out:
106 if (dec_ticket)
107 krb5_free_ticket(context, dec_ticket);
109 if (keytab)
110 krb5_kt_close(context, keytab);
112 *perr = ret;
113 return auth_ok;
116 /**********************************************************************************
117 Try to verify a ticket using the system keytab... the system keytab has kvno -1 entries, so
118 it's more like what microsoft does... see comment in utils/net_ads.c in the
119 ads_keytab_add_entry function for details.
120 ***********************************************************************************/
122 static bool ads_keytab_verify_ticket(krb5_context context,
123 krb5_auth_context auth_context,
124 const DATA_BLOB *ticket,
125 krb5_ticket **pp_tkt,
126 krb5_keyblock **keyblock,
127 krb5_error_code *perr)
129 krb5_error_code ret = 0;
130 bool auth_ok = False;
131 krb5_keytab keytab = NULL;
132 krb5_kt_cursor kt_cursor;
133 krb5_keytab_entry kt_entry;
134 char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
135 char *entry_princ_s = NULL;
136 fstring my_name, my_fqdn;
137 int i;
138 int number_matched_principals = 0;
139 krb5_data packet;
141 *pp_tkt = NULL;
142 *keyblock = NULL;
143 *perr = 0;
145 /* Generate the list of principal names which we expect
146 * clients might want to use for authenticating to the file
147 * service. We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
149 fstrcpy(my_name, global_myname());
151 my_fqdn[0] = '\0';
152 name_to_fqdn(my_fqdn, global_myname());
154 if (asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm()) == -1) {
155 goto out;
157 if (asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm()) == -1) {
158 goto out;
160 if (asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm()) == -1) {
161 goto out;
163 if (asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm()) == -1) {
164 goto out;
166 if (asprintf(&valid_princ_formats[4], "cifs/%s@%s", my_name, lp_realm()) == -1) {
167 goto out;
169 if (asprintf(&valid_princ_formats[5], "cifs/%s@%s", my_fqdn, lp_realm()) == -1) {
170 goto out;
172 if (asprintf(&valid_princ_formats[6], "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm()) == -1) {
173 goto out;
176 ZERO_STRUCT(kt_entry);
177 ZERO_STRUCT(kt_cursor);
179 ret = smb_krb5_open_keytab(context, NULL, False, &keytab);
180 if (ret) {
181 DEBUG(1, ("ads_keytab_verify_ticket: smb_krb5_open_keytab failed (%s)\n", error_message(ret)));
182 goto out;
185 /* Iterate through the keytab. For each key, if the principal
186 * name case-insensitively matches one of the allowed formats,
187 * try verifying the ticket using that principal. */
189 ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
190 if (ret) {
191 DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", error_message(ret)));
192 goto out;
195 while (!auth_ok && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
196 ret = smb_krb5_unparse_name(talloc_tos(), context, kt_entry.principal, &entry_princ_s);
197 if (ret) {
198 DEBUG(1, ("ads_keytab_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
199 error_message(ret)));
200 goto out;
203 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
205 if (!strequal(entry_princ_s, valid_princ_formats[i])) {
206 continue;
209 number_matched_principals++;
210 packet.length = ticket->length;
211 packet.data = (char *)ticket->data;
212 *pp_tkt = NULL;
214 ret = krb5_rd_req_return_keyblock_from_keytab(context, &auth_context, &packet,
215 kt_entry.principal, keytab,
216 NULL, pp_tkt, keyblock);
218 if (ret) {
219 DEBUG(10,("ads_keytab_verify_ticket: "
220 "krb5_rd_req_return_keyblock_from_keytab(%s) failed: %s\n",
221 entry_princ_s, error_message(ret)));
223 /* workaround for MIT:
224 * as krb5_ktfile_get_entry will explicitly
225 * close the krb5_keytab as soon as krb5_rd_req
226 * has successfully decrypted the ticket but the
227 * ticket is not valid yet (due to clockskew)
228 * there is no point in querying more keytab
229 * entries - Guenther */
231 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
232 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
233 ret == KRB5KRB_AP_ERR_SKEW) {
234 break;
236 } else {
237 DEBUG(3,("ads_keytab_verify_ticket: "
238 "krb5_rd_req_return_keyblock_from_keytab succeeded for principal %s\n",
239 entry_princ_s));
240 auth_ok = True;
241 break;
245 /* Free the name we parsed. */
246 TALLOC_FREE(entry_princ_s);
248 /* Free the entry we just read. */
249 smb_krb5_kt_free_entry(context, &kt_entry);
250 ZERO_STRUCT(kt_entry);
252 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
254 ZERO_STRUCT(kt_cursor);
256 out:
258 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
259 SAFE_FREE(valid_princ_formats[i]);
262 if (!auth_ok) {
263 if (!number_matched_principals) {
264 DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
265 } else {
266 DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
267 number_matched_principals));
271 SAFE_FREE(entry_princ_s);
274 krb5_keytab_entry zero_kt_entry;
275 ZERO_STRUCT(zero_kt_entry);
276 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
277 smb_krb5_kt_free_entry(context, &kt_entry);
282 krb5_kt_cursor zero_csr;
283 ZERO_STRUCT(zero_csr);
284 if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
285 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
289 if (keytab) {
290 krb5_kt_close(context, keytab);
292 *perr = ret;
293 return auth_ok;
296 /**********************************************************************************
297 Try to verify a ticket using the secrets.tdb.
298 ***********************************************************************************/
300 static krb5_error_code ads_secrets_verify_ticket(krb5_context context,
301 krb5_auth_context auth_context,
302 krb5_principal host_princ,
303 const DATA_BLOB *ticket,
304 krb5_ticket **pp_tkt,
305 krb5_keyblock **keyblock,
306 krb5_error_code *perr)
308 krb5_error_code ret = 0;
309 bool auth_ok = False;
310 char *password_s = NULL;
311 krb5_data password;
312 krb5_enctype enctypes[] = {
313 #if defined(ENCTYPE_ARCFOUR_HMAC)
314 ENCTYPE_ARCFOUR_HMAC,
315 #endif
316 ENCTYPE_DES_CBC_CRC,
317 ENCTYPE_DES_CBC_MD5,
318 ENCTYPE_NULL
320 krb5_data packet;
321 int i;
323 *pp_tkt = NULL;
324 *keyblock = NULL;
325 *perr = 0;
328 if (!secrets_init()) {
329 DEBUG(1,("ads_secrets_verify_ticket: secrets_init failed\n"));
330 *perr = KRB5_CONFIG_CANTOPEN;
331 return False;
334 password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
335 if (!password_s) {
336 DEBUG(1,("ads_secrets_verify_ticket: failed to fetch machine password\n"));
337 *perr = KRB5_LIBOS_CANTREADPWD;
338 return False;
341 password.data = password_s;
342 password.length = strlen(password_s);
344 /* CIFS doesn't use addresses in tickets. This would break NAT. JRA */
346 packet.length = ticket->length;
347 packet.data = (char *)ticket->data;
349 /* We need to setup a auth context with each possible encoding type in turn. */
350 for (i=0;enctypes[i];i++) {
351 krb5_keyblock *key = NULL;
353 if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
354 ret = ENOMEM;
355 goto out;
358 if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i], false)) {
359 SAFE_FREE(key);
360 continue;
363 krb5_auth_con_setuseruserkey(context, auth_context, key);
365 if (!(ret = krb5_rd_req(context, &auth_context, &packet,
366 NULL,
367 NULL, NULL, pp_tkt))) {
368 DEBUG(10,("ads_secrets_verify_ticket: enc type [%u] decrypted message !\n",
369 (unsigned int)enctypes[i] ));
370 auth_ok = True;
371 krb5_copy_keyblock(context, key, keyblock);
372 krb5_free_keyblock(context, key);
373 break;
376 DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
377 ("ads_secrets_verify_ticket: enc type [%u] failed to decrypt with error %s\n",
378 (unsigned int)enctypes[i], error_message(ret)));
380 /* successfully decrypted but ticket is just not valid at the moment */
381 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
382 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
383 ret == KRB5KRB_AP_ERR_SKEW) {
384 krb5_free_keyblock(context, key);
385 break;
388 krb5_free_keyblock(context, key);
392 out:
393 SAFE_FREE(password_s);
394 *perr = ret;
395 return auth_ok;
398 /**********************************************************************************
399 Verify an incoming ticket and parse out the principal name and
400 authorization_data if available.
401 ***********************************************************************************/
403 NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx,
404 const char *realm,
405 time_t time_offset,
406 const DATA_BLOB *ticket,
407 char **principal,
408 struct PAC_DATA **pac_data,
409 DATA_BLOB *ap_rep,
410 DATA_BLOB *session_key,
411 bool use_replay_cache)
413 NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
414 NTSTATUS pac_ret;
415 DATA_BLOB auth_data;
416 krb5_context context = NULL;
417 krb5_auth_context auth_context = NULL;
418 krb5_data packet;
419 krb5_ticket *tkt = NULL;
420 krb5_rcache rcache = NULL;
421 krb5_keyblock *keyblock = NULL;
422 time_t authtime;
423 krb5_error_code ret = 0;
424 int flags = 0;
425 krb5_principal host_princ = NULL;
426 krb5_const_principal client_principal = NULL;
427 char *host_princ_s = NULL;
428 bool auth_ok = False;
429 bool got_auth_data = False;
430 struct named_mutex *mutex = NULL;
432 ZERO_STRUCT(packet);
433 ZERO_STRUCT(auth_data);
435 *principal = NULL;
436 *pac_data = NULL;
437 *ap_rep = data_blob_null;
438 *session_key = data_blob_null;
440 initialize_krb5_error_table();
441 ret = krb5_init_context(&context);
442 if (ret) {
443 DEBUG(1,("ads_verify_ticket: krb5_init_context failed (%s)\n", error_message(ret)));
444 return NT_STATUS_LOGON_FAILURE;
447 if (time_offset != 0) {
448 krb5_set_real_time(context, time(NULL) + time_offset, 0);
451 ret = krb5_set_default_realm(context, realm);
452 if (ret) {
453 DEBUG(1,("ads_verify_ticket: krb5_set_default_realm failed (%s)\n", error_message(ret)));
454 goto out;
457 /* This whole process is far more complex than I would
458 like. We have to go through all this to allow us to store
459 the secret internally, instead of using /etc/krb5.keytab */
461 ret = krb5_auth_con_init(context, &auth_context);
462 if (ret) {
463 DEBUG(1,("ads_verify_ticket: krb5_auth_con_init failed (%s)\n", error_message(ret)));
464 goto out;
467 krb5_auth_con_getflags( context, auth_context, &flags );
468 if ( !use_replay_cache ) {
469 /* Disable default use of a replay cache */
470 flags &= ~KRB5_AUTH_CONTEXT_DO_TIME;
471 krb5_auth_con_setflags( context, auth_context, flags );
474 if (asprintf(&host_princ_s, "%s$", global_myname()) == -1) {
475 goto out;
478 strlower_m(host_princ_s);
479 ret = smb_krb5_parse_name(context, host_princ_s, &host_princ);
480 if (ret) {
481 DEBUG(1,("ads_verify_ticket: smb_krb5_parse_name(%s) failed (%s)\n",
482 host_princ_s, error_message(ret)));
483 goto out;
487 if ( use_replay_cache ) {
489 /* Lock a mutex surrounding the replay as there is no
490 locking in the MIT krb5 code surrounding the replay
491 cache... */
493 mutex = grab_named_mutex(talloc_tos(), "replay cache mutex",
494 10);
495 if (mutex == NULL) {
496 DEBUG(1,("ads_verify_ticket: unable to protect "
497 "replay cache with mutex.\n"));
498 ret = KRB5_CC_IO;
499 goto out;
502 /* JRA. We must set the rcache here. This will prevent
503 replay attacks. */
505 ret = krb5_get_server_rcache(context,
506 krb5_princ_component(context, host_princ, 0),
507 &rcache);
508 if (ret) {
509 DEBUG(1,("ads_verify_ticket: krb5_get_server_rcache "
510 "failed (%s)\n", error_message(ret)));
511 goto out;
514 ret = krb5_auth_con_setrcache(context, auth_context, rcache);
515 if (ret) {
516 DEBUG(1,("ads_verify_ticket: krb5_auth_con_setrcache "
517 "failed (%s)\n", error_message(ret)));
518 goto out;
522 switch (lp_kerberos_method()) {
523 default:
524 case KERBEROS_VERIFY_SECRETS:
525 auth_ok = ads_secrets_verify_ticket(context, auth_context,
526 host_princ, ticket, &tkt, &keyblock, &ret);
527 break;
528 case KERBEROS_VERIFY_SYSTEM_KEYTAB:
529 auth_ok = ads_keytab_verify_ticket(context, auth_context,
530 ticket, &tkt, &keyblock, &ret);
531 break;
532 case KERBEROS_VERIFY_DEDICATED_KEYTAB:
533 auth_ok = ads_dedicated_keytab_verify_ticket(context,
534 auth_context, ticket, &tkt, &keyblock, &ret);
535 break;
536 case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
537 /* First try secrets.tdb and fallback to the krb5.keytab if
538 necessary. This is the pre 3.4 behavior when
539 "use kerberos keytab" was true.*/
540 auth_ok = ads_secrets_verify_ticket(context, auth_context,
541 host_princ, ticket, &tkt, &keyblock, &ret);
543 if (!auth_ok) {
544 /* Only fallback if we failed to decrypt the ticket */
545 if (ret != KRB5KRB_AP_ERR_TKT_NYV &&
546 ret != KRB5KRB_AP_ERR_TKT_EXPIRED &&
547 ret != KRB5KRB_AP_ERR_SKEW) {
548 auth_ok = ads_keytab_verify_ticket(context,
549 auth_context, ticket, &tkt, &keyblock,
550 &ret);
553 break;
556 if ( use_replay_cache ) {
557 TALLOC_FREE(mutex);
558 #if 0
559 /* Heimdal leaks here, if we fix the leak, MIT crashes */
560 if (rcache) {
561 krb5_rc_close(context, rcache);
563 #endif
566 if (!auth_ok) {
567 DEBUG(3,("ads_verify_ticket: krb5_rd_req with auth failed (%s)\n",
568 error_message(ret)));
569 /* Try map the error return in case it's something like
570 * a clock skew error.
572 sret = krb5_to_nt_status(ret);
573 if (NT_STATUS_IS_OK(sret) || NT_STATUS_EQUAL(sret,NT_STATUS_UNSUCCESSFUL)) {
574 sret = NT_STATUS_LOGON_FAILURE;
576 DEBUG(10,("ads_verify_ticket: returning error %s\n",
577 nt_errstr(sret) ));
578 goto out;
581 authtime = get_authtime_from_tkt(tkt);
582 client_principal = get_principal_from_tkt(tkt);
584 ret = krb5_mk_rep(context, auth_context, &packet);
585 if (ret) {
586 DEBUG(3,("ads_verify_ticket: Failed to generate mutual authentication reply (%s)\n",
587 error_message(ret)));
588 goto out;
591 *ap_rep = data_blob(packet.data, packet.length);
592 if (packet.data) {
593 kerberos_free_data_contents(context, &packet);
594 ZERO_STRUCT(packet);
597 get_krb5_smb_session_key(context, auth_context, session_key, True);
598 dump_data_pw("SMB session key (from ticket)\n", session_key->data, session_key->length);
600 #if 0
601 file_save("/tmp/ticket.dat", ticket->data, ticket->length);
602 #endif
604 /* continue when no PAC is retrieved or we couldn't decode the PAC
605 (like accounts that have the UF_NO_AUTH_DATA_REQUIRED flag set, or
606 Kerberos tickets encrypted using a DES key) - Guenther */
608 got_auth_data = get_auth_data_from_tkt(mem_ctx, &auth_data, tkt);
609 if (!got_auth_data) {
610 DEBUG(3,("ads_verify_ticket: did not retrieve auth data. continuing without PAC\n"));
613 if (got_auth_data) {
614 pac_ret = decode_pac_data(mem_ctx, &auth_data, context, keyblock, client_principal, authtime, pac_data);
615 if (!NT_STATUS_IS_OK(pac_ret)) {
616 DEBUG(3,("ads_verify_ticket: failed to decode PAC_DATA: %s\n", nt_errstr(pac_ret)));
617 *pac_data = NULL;
619 data_blob_free(&auth_data);
622 #if 0
623 #if defined(HAVE_KRB5_TKT_ENC_PART2)
624 /* MIT */
625 if (tkt->enc_part2) {
626 file_save("/tmp/authdata.dat",
627 tkt->enc_part2->authorization_data[0]->contents,
628 tkt->enc_part2->authorization_data[0]->length);
630 #else
631 /* Heimdal */
632 if (tkt->ticket.authorization_data) {
633 file_save("/tmp/authdata.dat",
634 tkt->ticket.authorization_data->val->ad_data.data,
635 tkt->ticket.authorization_data->val->ad_data.length);
637 #endif
638 #endif
640 if ((ret = smb_krb5_unparse_name(mem_ctx, context, client_principal, principal))) {
641 DEBUG(3,("ads_verify_ticket: smb_krb5_unparse_name failed (%s)\n",
642 error_message(ret)));
643 sret = NT_STATUS_LOGON_FAILURE;
644 goto out;
647 sret = NT_STATUS_OK;
649 out:
651 TALLOC_FREE(mutex);
653 if (!NT_STATUS_IS_OK(sret)) {
654 data_blob_free(&auth_data);
657 if (!NT_STATUS_IS_OK(sret)) {
658 data_blob_free(ap_rep);
661 if (host_princ) {
662 krb5_free_principal(context, host_princ);
665 if (keyblock) {
666 krb5_free_keyblock(context, keyblock);
669 if (tkt != NULL) {
670 krb5_free_ticket(context, tkt);
673 SAFE_FREE(host_princ_s);
675 if (auth_context) {
676 krb5_auth_con_free(context, auth_context);
679 if (context) {
680 krb5_free_context(context);
683 return sret;
686 #endif /* HAVE_KRB5 */