Line data Source code
1 : /*
2 : Unix SMB/CIFS implementation.
3 :
4 : KDC Server startup
5 :
6 : Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2008
7 : Copyright (C) Andrew Tridgell 2005
8 : Copyright (C) Stefan Metzmacher 2005
9 :
10 : This program is free software; you can redistribute it and/or modify
11 : it under the terms of the GNU General Public License as published by
12 : the Free Software Foundation; either version 3 of the License, or
13 : (at your option) any later version.
14 :
15 : This program is distributed in the hope that it will be useful,
16 : but WITHOUT ANY WARRANTY; without even the implied warranty of
17 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 : GNU General Public License for more details.
19 :
20 : You should have received a copy of the GNU General Public License
21 : along with this program. If not, see <http://www.gnu.org/licenses/>.
22 : */
23 :
24 : #include "includes.h"
25 : #include "samba/process_model.h"
26 : #include "lib/tsocket/tsocket.h"
27 : #include "lib/messaging/irpc.h"
28 : #include "librpc/gen_ndr/ndr_irpc.h"
29 : #include "librpc/gen_ndr/ndr_krb5pac.h"
30 : #include "lib/socket/netif.h"
31 : #include "param/param.h"
32 : #include "kdc/kdc-server.h"
33 : #include "kdc/kdc-proxy.h"
34 : #include "kdc/kdc-glue.h"
35 : #include "kdc/pac-glue.h"
36 : #include "kdc/kpasswd-service.h"
37 : #include "dsdb/samdb/samdb.h"
38 : #include "auth/session.h"
39 : #include "libds/common/roles.h"
40 : #include <kdc.h>
41 : #include <hdb.h>
42 :
43 : #undef DBGC_CLASS
44 : #define DBGC_CLASS DBGC_KERBEROS
45 :
46 : NTSTATUS server_service_kdc_init(TALLOC_CTX *);
47 :
48 : extern struct krb5plugin_kdc_ftable kdc_plugin_table;
49 :
50 : /**
51 : Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
52 : calling conventions
53 : */
54 :
55 103738 : static kdc_code kdc_process(struct kdc_server *kdc,
56 : TALLOC_CTX *mem_ctx,
57 : DATA_BLOB *input,
58 : DATA_BLOB *reply,
59 : struct tsocket_address *peer_addr,
60 : struct tsocket_address *my_addr,
61 : int datagram_reply)
62 : {
63 3448 : int ret;
64 3448 : char *pa;
65 3448 : struct sockaddr_storage ss;
66 3448 : krb5_data k5_reply;
67 103738 : krb5_kdc_configuration *kdc_config = kdc->private_data;
68 :
69 103738 : krb5_data_zero(&k5_reply);
70 :
71 103738 : krb5_kdc_update_time(NULL);
72 :
73 103738 : ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
74 : sizeof(struct sockaddr_storage));
75 103738 : if (ret < 0) {
76 0 : return KDC_ERROR;
77 : }
78 103738 : pa = tsocket_address_string(peer_addr, mem_ctx);
79 103738 : if (pa == NULL) {
80 0 : return KDC_ERROR;
81 : }
82 :
83 103738 : DBG_DEBUG("Received KDC packet of length %zu from %s\n",
84 : input->length, pa);
85 :
86 107186 : ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
87 : kdc_config,
88 103738 : input->data, input->length,
89 : &k5_reply,
90 : pa,
91 : (struct sockaddr *) &ss,
92 : datagram_reply);
93 103738 : if (ret == -1) {
94 0 : *reply = data_blob(NULL, 0);
95 0 : return KDC_ERROR;
96 : }
97 :
98 103738 : if (ret == HDB_ERR_NOT_FOUND_HERE) {
99 3041 : *reply = data_blob(NULL, 0);
100 3041 : return KDC_PROXY_REQUEST;
101 : }
102 :
103 100697 : if (k5_reply.length) {
104 100697 : *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
105 100697 : krb5_data_free(&k5_reply);
106 : } else {
107 0 : *reply = data_blob(NULL, 0);
108 : }
109 97249 : return KDC_OK;
110 : }
111 :
112 : /*
113 : setup our listening sockets on the configured network interfaces
114 : */
115 42 : static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc,
116 : struct loadparm_context *lp_ctx,
117 : struct interface *ifaces,
118 : const struct model_ops *model_ops)
119 : {
120 2 : int num_interfaces;
121 42 : TALLOC_CTX *tmp_ctx = talloc_new(kdc);
122 2 : NTSTATUS status;
123 2 : int i;
124 42 : uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
125 42 : uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
126 42 : bool done_wildcard = false;
127 :
128 42 : num_interfaces = iface_list_count(ifaces);
129 :
130 : /* if we are allowing incoming packets from any address, then
131 : we need to bind to the wildcard address */
132 42 : if (!lpcfg_bind_interfaces_only(lp_ctx)) {
133 42 : size_t num_binds = 0;
134 42 : char **wcard = iface_list_wildcard(kdc);
135 42 : NT_STATUS_HAVE_NO_MEMORY(wcard);
136 126 : for (i=0; wcard[i]; i++) {
137 84 : if (kdc_port) {
138 84 : status = kdc_add_socket(kdc, model_ops,
139 80 : "kdc", wcard[i], kdc_port,
140 : kdc_process, false);
141 84 : if (NT_STATUS_IS_OK(status)) {
142 84 : num_binds++;
143 : }
144 : }
145 :
146 84 : if (kpasswd_port) {
147 84 : status = kdc_add_socket(kdc, model_ops,
148 80 : "kpasswd", wcard[i], kpasswd_port,
149 : kpasswd_process, false);
150 84 : if (NT_STATUS_IS_OK(status)) {
151 84 : num_binds++;
152 : }
153 : }
154 : }
155 42 : talloc_free(wcard);
156 42 : if (num_binds == 0) {
157 0 : return NT_STATUS_INVALID_PARAMETER_MIX;
158 : }
159 40 : done_wildcard = true;
160 : }
161 :
162 126 : for (i=0; i<num_interfaces; i++) {
163 84 : const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
164 :
165 84 : if (kdc_port) {
166 84 : status = kdc_add_socket(kdc, model_ops,
167 : "kdc", address, kdc_port,
168 : kdc_process, done_wildcard);
169 84 : NT_STATUS_NOT_OK_RETURN(status);
170 : }
171 :
172 84 : if (kpasswd_port) {
173 84 : status = kdc_add_socket(kdc, model_ops,
174 : "kpasswd", address, kpasswd_port,
175 : kpasswd_process, done_wildcard);
176 84 : NT_STATUS_NOT_OK_RETURN(status);
177 : }
178 : }
179 :
180 42 : talloc_free(tmp_ctx);
181 :
182 42 : return NT_STATUS_OK;
183 : }
184 :
185 150 : static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
186 : struct kdc_check_generic_kerberos *r)
187 : {
188 0 : struct PAC_Validate pac_validate;
189 0 : DATA_BLOB srv_sig;
190 0 : struct PAC_SIGNATURE_DATA kdc_sig;
191 150 : struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
192 150 : krb5_kdc_configuration *kdc_config =
193 : (krb5_kdc_configuration *)kdc->private_data;
194 0 : enum ndr_err_code ndr_err;
195 0 : int ret;
196 0 : hdb_entry ent;
197 0 : krb5_principal principal;
198 :
199 :
200 : /* There is no reply to this request */
201 150 : r->out.generic_reply = data_blob(NULL, 0);
202 :
203 150 : ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
204 : (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
205 150 : if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
206 0 : return NT_STATUS_INVALID_PARAMETER;
207 : }
208 :
209 150 : if (pac_validate.MessageType != NETLOGON_GENERIC_KRB5_PAC_VALIDATE) {
210 : /* We don't implement any other message types - such as certificate validation - yet */
211 0 : return NT_STATUS_INVALID_PARAMETER;
212 : }
213 :
214 150 : if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
215 90 : || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
216 90 : || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
217 60 : return NT_STATUS_INVALID_PARAMETER;
218 : }
219 :
220 90 : srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
221 90 : pac_validate.ChecksumLength);
222 :
223 90 : ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
224 90 : lpcfg_realm(kdc->task->lp_ctx),
225 90 : "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
226 : NULL);
227 :
228 90 : if (ret != 0) {
229 0 : return NT_STATUS_NO_MEMORY;
230 : }
231 :
232 90 : ret = kdc_config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
233 90 : kdc_config->db[0],
234 : principal,
235 : HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
236 : 0,
237 : &ent);
238 :
239 90 : if (ret != 0) {
240 0 : hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
241 0 : krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
242 :
243 0 : return NT_STATUS_LOGON_FAILURE;
244 : }
245 :
246 90 : kdc_sig.type = pac_validate.SignatureType;
247 90 : kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
248 90 : pac_validate.SignatureLength);
249 :
250 90 : ret = kdc_check_pac(kdc->smb_krb5_context->krb5_context, srv_sig, &kdc_sig, &ent);
251 :
252 90 : hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
253 90 : krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
254 :
255 90 : if (ret != 0) {
256 60 : return NT_STATUS_LOGON_FAILURE;
257 : }
258 :
259 30 : return NT_STATUS_OK;
260 : }
261 :
262 :
263 : /*
264 : startup the kdc task
265 : */
266 45 : static NTSTATUS kdc_task_init(struct task_server *task)
267 : {
268 2 : struct kdc_server *kdc;
269 2 : NTSTATUS status;
270 2 : struct interface *ifaces;
271 :
272 45 : switch (lpcfg_server_role(task->lp_ctx)) {
273 0 : case ROLE_STANDALONE:
274 0 : task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
275 0 : return NT_STATUS_INVALID_DOMAIN_ROLE;
276 3 : case ROLE_DOMAIN_MEMBER:
277 3 : task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
278 0 : return NT_STATUS_INVALID_DOMAIN_ROLE;
279 0 : case ROLE_DOMAIN_PDC:
280 : case ROLE_DOMAIN_BDC:
281 : case ROLE_IPA_DC:
282 0 : task_server_terminate(
283 : task, "Cannot start KDC as a 'classic Samba' DC", false);
284 0 : return NT_STATUS_INVALID_DOMAIN_ROLE;
285 40 : case ROLE_ACTIVE_DIRECTORY_DC:
286 : /* Yes, we want a KDC */
287 40 : break;
288 : }
289 :
290 42 : load_interface_list(task, task->lp_ctx, &ifaces);
291 :
292 42 : if (iface_list_count(ifaces) == 0) {
293 0 : task_server_terminate(task, "kdc: no network interfaces configured", false);
294 0 : return NT_STATUS_UNSUCCESSFUL;
295 : }
296 :
297 42 : task_server_set_title(task, "task[kdc]");
298 :
299 42 : kdc = talloc_zero(task, struct kdc_server);
300 42 : if (kdc == NULL) {
301 0 : task_server_terminate(task, "kdc: out of memory", true);
302 0 : return NT_STATUS_NO_MEMORY;
303 : }
304 :
305 42 : kdc->task = task;
306 42 : task->private_data = kdc;
307 :
308 : /* start listening on the configured network interfaces */
309 42 : status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces,
310 : task->model_ops);
311 42 : if (!NT_STATUS_IS_OK(status)) {
312 0 : task_server_terminate(task, "kdc failed to setup interfaces", true);
313 0 : return status;
314 : }
315 :
316 :
317 42 : return NT_STATUS_OK;
318 : }
319 :
320 : /*
321 : initialise the kdc task after a fork
322 : */
323 93 : static void kdc_post_fork(struct task_server *task, struct process_details *pd)
324 : {
325 8 : struct kdc_server *kdc;
326 93 : krb5_kdc_configuration *kdc_config = NULL;
327 8 : NTSTATUS status;
328 8 : krb5_error_code ret;
329 8 : int ldb_ret;
330 :
331 93 : if (task == NULL) {
332 0 : task_server_terminate(task, "kdc: Null task", true);
333 0 : return;
334 : }
335 93 : if (task->private_data == NULL) {
336 0 : task_server_terminate(task, "kdc: No kdc_server info", true);
337 0 : return;
338 : }
339 93 : kdc = talloc_get_type_abort(task->private_data, struct kdc_server);
340 :
341 : /* get a samdb connection */
342 279 : kdc->samdb = samdb_connect(kdc,
343 85 : kdc->task->event_ctx,
344 93 : kdc->task->lp_ctx,
345 93 : system_session(kdc->task->lp_ctx),
346 : NULL,
347 : 0);
348 93 : if (!kdc->samdb) {
349 0 : DBG_WARNING("kdc_task_init: unable to connect to samdb\n");
350 0 : task_server_terminate(task, "kdc: krb5_init_context samdb connect failed", true);
351 0 : return;
352 : }
353 :
354 93 : ldb_ret = samdb_rodc(kdc->samdb, &kdc->am_rodc);
355 93 : if (ldb_ret != LDB_SUCCESS) {
356 0 : DBG_WARNING("kdc_task_init: "
357 : "Cannot determine if we are an RODC: %s\n",
358 : ldb_errstring(kdc->samdb));
359 0 : task_server_terminate(task, "kdc: krb5_init_context samdb RODC connect failed", true);
360 0 : return;
361 : }
362 :
363 93 : kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);
364 :
365 93 : initialize_krb5_error_table();
366 :
367 93 : ret = smb_krb5_init_context(kdc, task->lp_ctx, &kdc->smb_krb5_context);
368 93 : if (ret) {
369 0 : DBG_WARNING("kdc_task_init: krb5_init_context failed (%s)\n",
370 : error_message(ret));
371 0 : task_server_terminate(task, "kdc: krb5_init_context failed", true);
372 0 : return;
373 : }
374 :
375 93 : krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
376 :
377 93 : ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
378 : &kdc_config);
379 93 : if(ret) {
380 0 : task_server_terminate(task, "kdc: failed to get KDC configuration", true);
381 0 : return;
382 : }
383 :
384 93 : kdc_config->logf = (krb5_log_facility *)kdc->smb_krb5_context->pvt_log_data;
385 93 : kdc_config->db = talloc(kdc, struct HDB *);
386 93 : if (!kdc_config->db) {
387 0 : task_server_terminate(task, "kdc: out of memory", true);
388 0 : return;
389 : }
390 93 : kdc_config->num_db = 1;
391 :
392 : /*
393 : * Note with the CVE-2022-37966 patches,
394 : * see https://bugzilla.samba.org/show_bug.cgi?id=15219
395 : * and https://bugzilla.samba.org/show_bug.cgi?id=15237
396 : * we want to use the strongest keys for everything.
397 : *
398 : * Some of these don't have any real effect anymore,
399 : * but it is better to have them as true...
400 : */
401 93 : kdc_config->tgt_use_strongest_session_key = true;
402 93 : kdc_config->preauth_use_strongest_session_key = true;
403 93 : kdc_config->svc_use_strongest_session_key = true;
404 93 : kdc_config->use_strongest_server_key = true;
405 :
406 93 : kdc_config->force_include_pa_etype_salt = true;
407 :
408 : /*
409 : * For Samba CVE-2020-25719 Require PAC to be present
410 : * This instructs Heimdal to match AD behaviour,
411 : * as seen after Microsoft's CVE-2021-42287 when
412 : * PacRequestorEnforcement is set to 2.
413 : *
414 : * Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=14686
415 : * REF: https://support.microsoft.com/en-au/topic/kb5008380-authentication-updates-cve-2021-42287-9dafac11-e0d0-4cb8-959a-143bd0201041
416 : */
417 :
418 93 : kdc_config->require_pac = true;
419 :
420 : /*
421 : * By default we enable RFC6113/FAST support,
422 : * but we have an option to disable in order to
423 : * test against a KDC with FAST support.
424 : */
425 93 : kdc_config->enable_fast = lpcfg_kdc_enable_fast(task->lp_ctx);
426 :
427 : {
428 8 : static const char *dummy_string = "Microsoft";
429 :
430 : /*
431 : * The FAST cookie is not cryptographically required,
432 : * provided that the non-AD gss-preauth authentication
433 : * method is removed (as this is the only multi-step
434 : * authentication method).
435 : *
436 : * gss-preauth has been disabled both by not being
437 : * configured and by being made dependent
438 : * configuration for a "real" fast cookie.
439 : *
440 : * The hide_client_names feature in Heimdal is the
441 : * only other state that is persisted in the cookie,
442 : * and this does not need to be in the cookie for
443 : * single-shot authentication protocols such as ENC-TS
444 : * and ENC-CHAL, the standard password protocols in
445 : * AD.
446 : *
447 : * Furthermore, the Heimdal KDC does not fail if the
448 : * client does not supply a FAST cookie, showing that
449 : * the presence of the cookie is not required.
450 : */
451 93 : kdc_config->enable_fast_cookie = false;
452 93 : kdc_config->dummy_fast_cookie = smb_krb5_make_data(discard_const_p(char, dummy_string),
453 : strlen(dummy_string));
454 : }
455 :
456 : /*
457 : * Match Windows and RFC6113 and Windows but break older
458 : * Heimdal clients.
459 : */
460 93 : kdc_config->enable_armored_pa_enc_timestamp = false;
461 :
462 : /* Register hdb-samba4 hooks for use as a keytab */
463 :
464 93 : kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
465 93 : if (!kdc->base_ctx) {
466 0 : task_server_terminate(task, "kdc: out of memory", true);
467 0 : return;
468 : }
469 :
470 93 : kdc->base_ctx->ev_ctx = task->event_ctx;
471 93 : kdc->base_ctx->lp_ctx = task->lp_ctx;
472 93 : kdc->base_ctx->msg_ctx = task->msg_ctx;
473 :
474 101 : status = hdb_samba4_create_kdc(kdc->base_ctx,
475 93 : kdc->smb_krb5_context->krb5_context,
476 93 : &kdc_config->db[0]);
477 93 : if (!NT_STATUS_IS_OK(status)) {
478 0 : task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
479 0 : return;
480 : }
481 :
482 93 : ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
483 : PLUGIN_TYPE_DATA, "hdb_samba4_interface",
484 : &hdb_samba4_interface);
485 93 : if(ret) {
486 0 : task_server_terminate(task, "kdc: failed to register hdb plugin", true);
487 0 : return;
488 : }
489 :
490 93 : kdc->kpasswd_keytab_name = talloc_asprintf(kdc, "HDBGET:samba4:&%p", kdc->base_ctx);
491 93 : if (kdc->kpasswd_keytab_name == NULL) {
492 0 : task_server_terminate(task,
493 : "kdc: Failed to set keytab name",
494 : true);
495 0 : return;
496 : }
497 :
498 93 : ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_get_kt_ops);
499 93 : if(ret) {
500 0 : task_server_terminate(task, "kdc: failed to register keytab plugin", true);
501 0 : return;
502 : }
503 :
504 : /* Register KDC hooks */
505 93 : ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
506 : PLUGIN_TYPE_DATA, "kdc",
507 : &kdc_plugin_table);
508 93 : if(ret) {
509 0 : task_server_terminate(task, "kdc: failed to register kdc plugin", true);
510 0 : return;
511 : }
512 :
513 93 : ret = krb5_kdc_plugin_init(kdc->smb_krb5_context->krb5_context);
514 :
515 93 : if(ret) {
516 0 : task_server_terminate(task, "kdc: failed to init kdc plugin", true);
517 0 : return;
518 : }
519 :
520 93 : ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc_config);
521 :
522 93 : if(ret) {
523 0 : task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
524 0 : return;
525 : }
526 93 : kdc->private_data = kdc_config;
527 :
528 93 : status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
529 : kdc_check_generic_kerberos, kdc);
530 93 : if (!NT_STATUS_IS_OK(status)) {
531 0 : task_server_terminate(task, "kdc failed to setup monitoring", true);
532 0 : return;
533 : }
534 :
535 93 : irpc_add_name(task->msg_ctx, "kdc_server");
536 : }
537 :
538 :
539 : /* called at smbd startup - register ourselves as a server service */
540 46 : NTSTATUS server_service_kdc_init(TALLOC_CTX *ctx)
541 : {
542 3 : static const struct service_details details = {
543 : .inhibit_fork_on_accept = true,
544 : .inhibit_pre_fork = false,
545 : .task_init = kdc_task_init,
546 : .post_fork = kdc_post_fork
547 : };
548 46 : return register_server_service(ctx, "kdc", &details);
549 : }
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