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/>.
28 #include "libads/kerberos_proto.h"
32 #if !defined(HAVE_KRB5_PRINC_COMPONENT)
33 const krb5_data *krb5_princ_component(krb5_context, krb5_principal, int );
36 static bool ads_dedicated_keytab_verify_ticket(krb5_context context,
37 krb5_auth_context auth_context,
38 const DATA_BLOB *ticket,
40 krb5_keyblock **keyblock,
41 krb5_error_code *perr)
43 krb5_error_code ret = 0;
45 krb5_keytab keytab = NULL;
46 krb5_keytab_entry kt_entry;
47 krb5_ticket *dec_ticket = NULL;
57 ZERO_STRUCT(kt_entry);
59 ret = smb_krb5_open_keytab(context, lp_dedicated_keytab_file(), true,
62 DEBUG(1, ("smb_krb5_open_keytab failed (%s)\n",
67 packet.length = ticket->length;
68 packet.data = (char *)ticket->data;
70 ret = krb5_rd_req(context, &auth_context, &packet, NULL, keytab,
73 DEBUG(0, ("krb5_rd_req failed (%s)\n", error_message(ret)));
77 #ifdef HAVE_ETYPE_IN_ENCRYPTEDDATA /* Heimdal */
78 enctype = dec_ticket->ticket.key.keytype;
80 enctype = dec_ticket->enc_part.enctype;
81 kvno = dec_ticket->enc_part.kvno;
84 /* Get the key for checking the pac signature */
85 ret = krb5_kt_get_entry(context, keytab, dec_ticket->server,
86 kvno, enctype, &kt_entry);
88 DEBUG(0, ("krb5_kt_get_entry failed (%s)\n",
93 ret = krb5_copy_keyblock(context, KRB5_KT_KEY(&kt_entry), keyblock);
94 smb_krb5_kt_free_entry(context, &kt_entry);
97 DEBUG(0, ("failed to copy key: %s\n",
103 *pp_tkt = dec_ticket;
108 krb5_free_ticket(context, dec_ticket);
111 krb5_kt_close(context, keytab);
117 /******************************************************************************
118 Try to verify a ticket using the system keytab... the system keytab has
119 kvno -1 entries, so it's more like what microsoft does... see comment in
120 utils/net_ads.c in the ads_keytab_add_entry function for details.
121 ******************************************************************************/
123 static bool ads_keytab_verify_ticket(krb5_context context,
124 krb5_auth_context auth_context,
125 const DATA_BLOB *ticket,
126 krb5_ticket **pp_tkt,
127 krb5_keyblock **keyblock,
128 krb5_error_code *perr)
130 krb5_error_code ret = 0;
131 bool auth_ok = False;
132 krb5_keytab keytab = NULL;
133 krb5_kt_cursor kt_cursor;
134 krb5_keytab_entry kt_entry;
135 char *valid_princ_formats[7] = { NULL, NULL, NULL,
136 NULL, NULL, NULL, NULL };
137 char *entry_princ_s = NULL;
138 fstring my_name, my_fqdn;
140 int number_matched_principals = 0;
148 /* Generate the list of principal names which we expect
149 * clients might want to use for authenticating to the file
150 * service. We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
152 fstrcpy(my_name, global_myname());
155 name_to_fqdn(my_fqdn, global_myname());
157 err = asprintf(&valid_princ_formats[0],
158 "%s$@%s", my_name, lp_realm());
162 err = asprintf(&valid_princ_formats[1],
163 "host/%s@%s", my_name, lp_realm());
167 err = asprintf(&valid_princ_formats[2],
168 "host/%s@%s", my_fqdn, lp_realm());
172 err = asprintf(&valid_princ_formats[3],
173 "host/%s.%s@%s", my_name, lp_realm(), lp_realm());
177 err = asprintf(&valid_princ_formats[4],
178 "cifs/%s@%s", my_name, lp_realm());
182 err = asprintf(&valid_princ_formats[5],
183 "cifs/%s@%s", my_fqdn, lp_realm());
187 err = asprintf(&valid_princ_formats[6],
188 "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm());
193 ZERO_STRUCT(kt_entry);
194 ZERO_STRUCT(kt_cursor);
196 ret = smb_krb5_open_keytab(context, NULL, False, &keytab);
198 DEBUG(1, (__location__ ": smb_krb5_open_keytab failed (%s)\n",
199 error_message(ret)));
203 /* Iterate through the keytab. For each key, if the principal
204 * name case-insensitively matches one of the allowed formats,
205 * try verifying the ticket using that principal. */
207 ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
209 DEBUG(1, (__location__ ": krb5_kt_start_seq_get failed (%s)\n",
210 error_message(ret)));
215 (krb5_kt_next_entry(context, keytab,
216 &kt_entry, &kt_cursor) == 0)) {
217 ret = smb_krb5_unparse_name(talloc_tos(), context,
221 DEBUG(1, (__location__ ": smb_krb5_unparse_name "
222 "failed (%s)\n", error_message(ret)));
226 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
228 if (!strequal(entry_princ_s, valid_princ_formats[i])) {
232 number_matched_principals++;
233 packet.length = ticket->length;
234 packet.data = (char *)ticket->data;
237 ret = krb5_rd_req_return_keyblock_from_keytab(context,
238 &auth_context, &packet,
239 kt_entry.principal, keytab,
240 NULL, pp_tkt, keyblock);
243 DEBUG(10, (__location__ ": krb5_rd_req_return"
244 "_keyblock_from_keytab(%s) "
245 "failed: %s\n", entry_princ_s,
246 error_message(ret)));
248 /* workaround for MIT:
249 * as krb5_ktfile_get_entry will explicitly
250 * close the krb5_keytab as soon as krb5_rd_req
251 * has successfully decrypted the ticket but the
252 * ticket is not valid yet (due to clockskew)
253 * there is no point in querying more keytab
254 * entries - Guenther */
256 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
257 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
258 ret == KRB5KRB_AP_ERR_SKEW) {
262 DEBUG(3, (__location__ ": krb5_rd_req_return"
263 "_keyblock_from_keytab succeeded "
264 "for principal %s\n",
271 /* Free the name we parsed. */
272 TALLOC_FREE(entry_princ_s);
274 /* Free the entry we just read. */
275 smb_krb5_kt_free_entry(context, &kt_entry);
276 ZERO_STRUCT(kt_entry);
278 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
280 ZERO_STRUCT(kt_cursor);
284 for (i = 0; i < ARRAY_SIZE(valid_princ_formats); i++) {
285 SAFE_FREE(valid_princ_formats[i]);
289 if (!number_matched_principals) {
290 DEBUG(3, (__location__ ": no keytab principals "
291 "matched expected file service name.\n"));
293 DEBUG(3, (__location__ ": krb5_rd_req failed for "
294 "all %d matched keytab principals\n",
295 number_matched_principals));
299 SAFE_FREE(entry_princ_s);
302 krb5_keytab_entry zero_kt_entry;
303 ZERO_STRUCT(zero_kt_entry);
304 if (memcmp(&zero_kt_entry, &kt_entry,
305 sizeof(krb5_keytab_entry))) {
306 smb_krb5_kt_free_entry(context, &kt_entry);
311 krb5_kt_cursor zero_csr;
312 ZERO_STRUCT(zero_csr);
313 if ((memcmp(&kt_cursor, &zero_csr,
314 sizeof(krb5_kt_cursor)) != 0) && keytab) {
315 krb5_kt_end_seq_get(context, keytab, &kt_cursor);
320 krb5_kt_close(context, keytab);
326 /*****************************************************************************
327 Try to verify a ticket using the secrets.tdb.
328 ******************************************************************************/
330 static krb5_error_code ads_secrets_verify_ticket(krb5_context context,
331 krb5_auth_context auth_context,
332 krb5_principal host_princ,
333 const DATA_BLOB *ticket,
334 krb5_ticket **pp_tkt,
335 krb5_keyblock **keyblock,
336 krb5_error_code *perr)
338 krb5_error_code ret = 0;
339 bool auth_ok = False;
341 char *password_s = NULL;
342 /* Let's make some room for 2 password (old and new)*/
343 krb5_data passwords[2];
344 krb5_enctype enctypes[] = {
345 #if defined(ENCTYPE_ARCFOUR_HMAC)
346 ENCTYPE_ARCFOUR_HMAC,
359 ZERO_STRUCT(passwords);
361 if (!secrets_init()) {
362 DEBUG(1,("ads_secrets_verify_ticket: secrets_init failed\n"));
363 *perr = KRB5_CONFIG_CANTOPEN;
367 password_s = secrets_fetch_machine_password(lp_workgroup(),
370 DEBUG(1,(__location__ ": failed to fetch machine password\n"));
371 *perr = KRB5_LIBOS_CANTREADPWD;
375 passwords[0].data = password_s;
376 passwords[0].length = strlen(password_s);
378 password_s = secrets_fetch_prev_machine_password(lp_workgroup());
380 DEBUG(10, (__location__ ": found previous password\n"));
381 passwords[1].data = password_s;
382 passwords[1].length = strlen(password_s);
385 /* CIFS doesn't use addresses in tickets. This would break NAT. JRA */
387 packet.length = ticket->length;
388 packet.data = (char *)ticket->data;
390 /* We need to setup a auth context with each possible encoding type
392 for (j=0; j<2 && passwords[j].length; j++) {
394 for (i=0;enctypes[i];i++) {
395 krb5_keyblock *key = NULL;
397 if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
402 if (create_kerberos_key_from_string(context,
403 host_princ, &passwords[j],
404 key, enctypes[i], false)) {
409 krb5_auth_con_setuseruserkey(context,
412 if (!(ret = krb5_rd_req(context, &auth_context,
415 DEBUG(10, (__location__ ": enc type [%u] "
416 "decrypted message !\n",
417 (unsigned int)enctypes[i]));
420 krb5_copy_keyblock(context, key, keyblock);
421 krb5_free_keyblock(context, key);
425 DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
426 (__location__ ": enc type [%u] failed to "
427 "decrypt with error %s\n",
428 (unsigned int)enctypes[i],
429 error_message(ret)));
431 /* successfully decrypted but ticket is just not
432 * valid at the moment */
433 if (ret == KRB5KRB_AP_ERR_TKT_NYV ||
434 ret == KRB5KRB_AP_ERR_TKT_EXPIRED ||
435 ret == KRB5KRB_AP_ERR_SKEW) {
436 krb5_free_keyblock(context, key);
441 krb5_free_keyblock(context, key);
444 /* If we found a valid pass then no need to try
445 * the next one or we have invalid ticket so no need
446 * to try next password*/
452 SAFE_FREE(passwords[0].data);
453 SAFE_FREE(passwords[1].data);
458 /*****************************************************************************
459 Verify an incoming ticket and parse out the principal name and
460 authorization_data if available.
461 ******************************************************************************/
463 NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx,
466 const DATA_BLOB *ticket,
468 struct PAC_LOGON_INFO **logon_info,
470 DATA_BLOB *session_key,
471 bool use_replay_cache)
473 NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
476 krb5_context context = NULL;
477 krb5_auth_context auth_context = NULL;
479 krb5_ticket *tkt = NULL;
480 krb5_rcache rcache = NULL;
481 krb5_keyblock *keyblock = NULL;
483 krb5_error_code ret = 0;
485 krb5_principal host_princ = NULL;
486 krb5_const_principal client_principal = NULL;
487 char *host_princ_s = NULL;
488 bool auth_ok = False;
489 bool got_auth_data = False;
490 struct named_mutex *mutex = NULL;
493 ZERO_STRUCT(auth_data);
497 *ap_rep = data_blob_null;
498 *session_key = data_blob_null;
500 initialize_krb5_error_table();
501 ret = krb5_init_context(&context);
503 DEBUG(1, (__location__ ": krb5_init_context failed (%s)\n",
504 error_message(ret)));
505 return NT_STATUS_LOGON_FAILURE;
508 if (time_offset != 0) {
509 krb5_set_real_time(context, time(NULL) + time_offset, 0);
512 ret = krb5_set_default_realm(context, realm);
514 DEBUG(1, (__location__ ": krb5_set_default_realm "
515 "failed (%s)\n", error_message(ret)));
519 /* This whole process is far more complex than I would
520 like. We have to go through all this to allow us to store
521 the secret internally, instead of using /etc/krb5.keytab */
523 ret = krb5_auth_con_init(context, &auth_context);
525 DEBUG(1, (__location__ ": krb5_auth_con_init failed (%s)\n",
526 error_message(ret)));
530 krb5_auth_con_getflags( context, auth_context, &flags );
531 if ( !use_replay_cache ) {
532 /* Disable default use of a replay cache */
533 flags &= ~KRB5_AUTH_CONTEXT_DO_TIME;
534 krb5_auth_con_setflags( context, auth_context, flags );
537 if (asprintf(&host_princ_s, "%s$", global_myname()) == -1) {
541 strlower_m(host_princ_s);
542 ret = smb_krb5_parse_name(context, host_princ_s, &host_princ);
544 DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
545 "failed (%s)\n", host_princ_s, error_message(ret)));
550 if (use_replay_cache) {
552 /* Lock a mutex surrounding the replay as there is no
553 locking in the MIT krb5 code surrounding the replay
556 mutex = grab_named_mutex(talloc_tos(),
557 "replay cache mutex", 10);
559 DEBUG(1, (__location__ ": unable to protect replay "
560 "cache with mutex.\n"));
565 /* JRA. We must set the rcache here. This will prevent
568 ret = krb5_get_server_rcache(
570 krb5_princ_component(context, host_princ, 0),
573 DEBUG(1, (__location__ ": krb5_get_server_rcache "
574 "failed (%s)\n", error_message(ret)));
578 ret = krb5_auth_con_setrcache(context, auth_context, rcache);
580 DEBUG(1, (__location__ ": krb5_auth_con_setrcache "
581 "failed (%s)\n", error_message(ret)));
586 switch (lp_kerberos_method()) {
588 case KERBEROS_VERIFY_SECRETS:
589 auth_ok = ads_secrets_verify_ticket(context, auth_context,
590 host_princ, ticket, &tkt, &keyblock, &ret);
592 case KERBEROS_VERIFY_SYSTEM_KEYTAB:
593 auth_ok = ads_keytab_verify_ticket(context, auth_context,
594 ticket, &tkt, &keyblock, &ret);
596 case KERBEROS_VERIFY_DEDICATED_KEYTAB:
597 auth_ok = ads_dedicated_keytab_verify_ticket(context,
598 auth_context, ticket, &tkt, &keyblock, &ret);
600 case KERBEROS_VERIFY_SECRETS_AND_KEYTAB:
601 /* First try secrets.tdb and fallback to the krb5.keytab if
602 necessary. This is the pre 3.4 behavior when
603 "use kerberos keytab" was true.*/
604 auth_ok = ads_secrets_verify_ticket(context, auth_context,
605 host_princ, ticket, &tkt, &keyblock, &ret);
608 /* Only fallback if we failed to decrypt the ticket */
609 if (ret != KRB5KRB_AP_ERR_TKT_NYV &&
610 ret != KRB5KRB_AP_ERR_TKT_EXPIRED &&
611 ret != KRB5KRB_AP_ERR_SKEW) {
612 auth_ok = ads_keytab_verify_ticket(context,
613 auth_context, ticket, &tkt, &keyblock,
620 if (use_replay_cache) {
623 /* Heimdal leaks here, if we fix the leak, MIT crashes */
625 krb5_rc_close(context, rcache);
631 DEBUG(3, (__location__ ": krb5_rd_req with auth "
632 "failed (%s)\n", error_message(ret)));
633 /* Try map the error return in case it's something like
634 * a clock skew error.
636 sret = krb5_to_nt_status(ret);
637 if (NT_STATUS_IS_OK(sret) ||
638 NT_STATUS_EQUAL(sret,NT_STATUS_UNSUCCESSFUL)) {
639 sret = NT_STATUS_LOGON_FAILURE;
641 DEBUG(10, (__location__ ": returning error %s\n",
646 authtime = get_authtime_from_tkt(tkt);
647 client_principal = get_principal_from_tkt(tkt);
649 ret = krb5_mk_rep(context, auth_context, &packet);
651 DEBUG(3, (__location__ ": Failed to generate mutual "
652 "authentication reply (%s)\n", error_message(ret)));
656 *ap_rep = data_blob(packet.data, packet.length);
658 kerberos_free_data_contents(context, &packet);
662 get_krb5_smb_session_key(mem_ctx, context,
663 auth_context, session_key, true);
664 dump_data_pw("SMB session key (from ticket)\n",
665 session_key->data, session_key->length);
668 file_save("/tmp/ticket.dat", ticket->data, ticket->length);
671 /* continue when no PAC is retrieved or we couldn't decode the PAC
672 (like accounts that have the UF_NO_AUTH_DATA_REQUIRED flag set, or
673 Kerberos tickets encrypted using a DES key) - Guenther */
675 got_auth_data = get_auth_data_from_tkt(mem_ctx, &auth_data, tkt);
676 if (!got_auth_data) {
677 DEBUG(3, (__location__ ": did not retrieve auth data. "
678 "continuing without PAC\n"));
682 struct PAC_DATA *pac_data;
683 pac_ret = decode_pac_data(mem_ctx, &auth_data, context,
684 keyblock, client_principal,
685 authtime, &pac_data);
686 data_blob_free(&auth_data);
687 if (!NT_STATUS_IS_OK(pac_ret)) {
688 DEBUG(3, (__location__ ": failed to decode "
689 "PAC_DATA: %s\n", nt_errstr(pac_ret)));
692 for (i = 0; i < pac_data->num_buffers; i++) {
694 if (pac_data->buffers[i].type != PAC_TYPE_LOGON_INFO) {
698 *logon_info = pac_data->buffers[i].info->logon_info.info;
702 DEBUG(1, ("correctly decoded PAC but found "
704 "This should not happen\n"));
705 return NT_STATUS_INVALID_USER_BUFFER;
711 #if defined(HAVE_KRB5_TKT_ENC_PART2)
713 if (tkt->enc_part2) {
714 file_save("/tmp/authdata.dat",
715 tkt->enc_part2->authorization_data[0]->contents,
716 tkt->enc_part2->authorization_data[0]->length);
720 if (tkt->ticket.authorization_data) {
721 file_save("/tmp/authdata.dat",
722 tkt->ticket.authorization_data->val->ad_data.data,
723 tkt->ticket.authorization_data->val->ad_data.length);
728 ret = smb_krb5_unparse_name(mem_ctx, context,
729 client_principal, principal);
731 DEBUG(3, (__location__ ": smb_krb5_unparse_name "
732 "failed (%s)\n", error_message(ret)));
733 sret = NT_STATUS_LOGON_FAILURE;
743 if (!NT_STATUS_IS_OK(sret)) {
744 data_blob_free(&auth_data);
747 if (!NT_STATUS_IS_OK(sret)) {
748 data_blob_free(ap_rep);
752 krb5_free_principal(context, host_princ);
756 krb5_free_keyblock(context, keyblock);
760 krb5_free_ticket(context, tkt);
763 SAFE_FREE(host_princ_s);
766 krb5_auth_con_free(context, auth_context);
770 krb5_free_context(context);
776 #endif /* HAVE_KRB5 */