3c625db7cc30c46d2bcd1eae28e3e52277f8aa6f
[sfrench/samba-autobuild/.git] / source4 / dsdb / dns / dns_update.c
1 /*
2    Unix SMB/CIFS mplementation.
3
4    DNS update service
5
6    Copyright (C) Andrew Tridgell 2009
7
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 3 of the License, or
11    (at your option) any later version.
12
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17
18    You should have received a copy of the GNU General Public License
19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
20
21 */
22
23 /*
24   this module auto-creates the named.conf.update file, which tells
25   bind9 what KRB5 principals it should accept for updates to our zone
26
27   It also uses the samba_dnsupdate script to auto-create the right DNS
28   names for ourselves as a DC in the domain, using TSIG-GSS
29  */
30
31 #include "includes.h"
32 #include "dsdb/samdb/samdb.h"
33 #include "auth/auth.h"
34 #include "smbd/service.h"
35 #include "lib/messaging/irpc.h"
36 #include "param/param.h"
37 #include "system/filesys.h"
38 #include "libcli/composite/composite.h"
39 #include "libcli/security/dom_sid.h"
40 #include "librpc/gen_ndr/ndr_irpc.h"
41
42 struct dnsupdate_service {
43         struct task_server *task;
44         struct auth_session_info *system_session_info;
45         struct ldb_context *samdb;
46
47         /* status for periodic config file update */
48         struct {
49                 uint32_t interval;
50                 struct tevent_timer *te;
51                 struct tevent_req *subreq;
52                 NTSTATUS status;
53         } confupdate;
54
55         /* status for periodic DNS name check */
56         struct {
57                 uint32_t interval;
58                 struct tevent_timer *te;
59                 struct tevent_req *subreq;
60                 struct tevent_req *spnreq;
61                 NTSTATUS status;
62         } nameupdate;
63 };
64
65 /*
66   called when rndc reload has finished
67  */
68 static void dnsupdate_rndc_done(struct tevent_req *subreq)
69 {
70         struct dnsupdate_service *service = tevent_req_callback_data(subreq,
71                                             struct dnsupdate_service);
72         int ret;
73         int sys_errno;
74
75         service->confupdate.subreq = NULL;
76
77         ret = samba_runcmd_recv(subreq, &sys_errno);
78         TALLOC_FREE(subreq);
79         if (ret != 0) {
80                 service->confupdate.status = map_nt_error_from_unix(sys_errno);
81         } else {
82                 service->confupdate.status = NT_STATUS_OK;
83         }
84
85         if (!NT_STATUS_IS_OK(service->confupdate.status)) {
86                 DEBUG(0,(__location__ ": Failed rndc update - %s\n",
87                          nt_errstr(service->confupdate.status)));
88         } else {
89                 DEBUG(3,("Completed rndc reload OK\n"));
90         }
91 }
92
93 /*
94   called every 'dnsupdate:conf interval' seconds
95  */
96 static void dnsupdate_rebuild(struct dnsupdate_service *service)
97 {
98         int ret;
99         size_t size;
100         struct ldb_result *res;
101         const char *tmp_path, *path, *path_static;
102         char *static_policies;
103         int fd;
104         unsigned int i;
105         const char *attrs[] = { "sAMAccountName", NULL };
106         const char *realm = lpcfg_realm(service->task->lp_ctx);
107         TALLOC_CTX *tmp_ctx = talloc_new(service);
108         const char * const *rndc_command = lpcfg_rndc_command(service->task->lp_ctx);
109
110         /* abort any pending script run */
111         TALLOC_FREE(service->confupdate.subreq);
112
113         ret = ldb_search(service->samdb, tmp_ctx, &res, NULL, LDB_SCOPE_SUBTREE,
114                          attrs, "(|(samaccountname=administrator)(&(primaryGroupID=%u)(objectClass=computer)))",
115                          DOMAIN_RID_DCS);
116         if (ret != LDB_SUCCESS) {
117                 DEBUG(0,(__location__ ": Unable to find DCs list - %s", ldb_errstring(service->samdb)));
118                 talloc_free(tmp_ctx);
119                 return;
120         }
121
122         path = lpcfg_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "path");
123         if (path == NULL) {
124                 path = private_path(tmp_ctx, service->task->lp_ctx, "named.conf.update");
125         }
126
127         path_static = lpcfg_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "extra_static_grant_rules");
128         if (path_static == NULL) {
129                 path_static = private_path(tmp_ctx, service->task->lp_ctx, "named.conf.update.static");
130         }
131
132         tmp_path = talloc_asprintf(tmp_ctx, "%s.tmp", path);
133         if (path == NULL || tmp_path == NULL || path_static == NULL ) {
134                 DEBUG(0,(__location__ ": Unable to get paths\n"));
135                 talloc_free(tmp_ctx);
136                 return;
137         }
138
139         static_policies = file_load(path_static, &size, 0, tmp_ctx);
140
141         unlink(tmp_path);
142         fd = open(tmp_path, O_CREAT|O_TRUNC|O_WRONLY, 0444);
143         if (fd == -1) {
144                 DEBUG(1,(__location__ ": Unable to open %s - %s\n", tmp_path, strerror(errno)));
145                 talloc_free(tmp_ctx);
146                 return;
147         }
148
149         dprintf(fd, "/* this file is auto-generated - do not edit */\n");
150         dprintf(fd, "update-policy {\n");
151         if( static_policies != NULL ) {
152                 dprintf(fd, "/* Start of static entries */\n");
153                 dprintf(fd, "%s\n",static_policies);
154                 dprintf(fd, "/* End of static entries */\n");
155         }
156         dprintf(fd, "\tgrant %s ms-self * A AAAA;\n", realm);
157
158         for (i=0; i<res->count; i++) {
159                 const char *acctname;
160                 acctname = ldb_msg_find_attr_as_string(res->msgs[i],
161                                                        "sAMAccountName", NULL);
162                 if (!acctname) continue;
163                 dprintf(fd, "\tgrant %s@%s wildcard * A AAAA SRV CNAME;\n",
164                         acctname, realm);
165         }
166         dprintf(fd, "};\n");
167         close(fd);
168
169
170         if (NT_STATUS_IS_OK(service->confupdate.status) &&
171             file_compare(tmp_path, path) == true) {
172                 unlink(tmp_path);
173                 talloc_free(tmp_ctx);
174                 return;
175         }
176
177         if (rename(tmp_path, path) != 0) {
178                 DEBUG(0,(__location__ ": Failed to rename %s to %s - %s\n",
179                          tmp_path, path, strerror(errno)));
180                 talloc_free(tmp_ctx);
181                 return;
182         }
183
184         DEBUG(2,("Loading new DNS update grant rules\n"));
185         service->confupdate.subreq = samba_runcmd_send(service,
186                                                        service->task->event_ctx,
187                                                        timeval_current_ofs(10, 0),
188                                                        2, 0,
189                                                        rndc_command,
190                                                        "reload", NULL);
191         if (service->confupdate.subreq == NULL) {
192                 DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
193                 talloc_free(tmp_ctx);
194                 return;
195         }
196         tevent_req_set_callback(service->confupdate.subreq,
197                                 dnsupdate_rndc_done,
198                                 service);
199
200         talloc_free(tmp_ctx);
201 }
202
203 static NTSTATUS dnsupdate_confupdate_schedule(struct dnsupdate_service *service);
204
205 /*
206   called every 'dnsupdate:conf interval' seconds
207  */
208 static void dnsupdate_confupdate_handler_te(struct tevent_context *ev, struct tevent_timer *te,
209                                           struct timeval t, void *ptr)
210 {
211         struct dnsupdate_service *service = talloc_get_type(ptr, struct dnsupdate_service);
212
213         dnsupdate_rebuild(service);
214         dnsupdate_confupdate_schedule(service);
215 }
216
217
218 static NTSTATUS dnsupdate_confupdate_schedule(struct dnsupdate_service *service)
219 {
220         service->confupdate.te = tevent_add_timer(service->task->event_ctx, service,
221                                                 timeval_current_ofs(service->confupdate.interval, 0),
222                                                 dnsupdate_confupdate_handler_te, service);
223         NT_STATUS_HAVE_NO_MEMORY(service->confupdate.te);
224         return NT_STATUS_OK;
225 }
226
227
228 /*
229   called when dns update script has finished
230  */
231 static void dnsupdate_nameupdate_done(struct tevent_req *subreq)
232 {
233         struct dnsupdate_service *service = tevent_req_callback_data(subreq,
234                                             struct dnsupdate_service);
235         int ret;
236         int sys_errno;
237
238         service->nameupdate.subreq = NULL;
239
240         ret = samba_runcmd_recv(subreq, &sys_errno);
241         TALLOC_FREE(subreq);
242         if (ret != 0) {
243                 service->nameupdate.status = map_nt_error_from_unix(sys_errno);
244         } else {
245                 service->nameupdate.status = NT_STATUS_OK;
246         }
247
248         if (!NT_STATUS_IS_OK(service->nameupdate.status)) {
249                 DEBUG(0,(__location__ ": Failed DNS update - %s\n",
250                          nt_errstr(service->nameupdate.status)));
251         } else {
252                 DEBUG(3,("Completed DNS update check OK\n"));
253         }
254 }
255
256
257 /*
258   called when spn update script has finished
259  */
260 static void dnsupdate_spnupdate_done(struct tevent_req *subreq)
261 {
262         struct dnsupdate_service *service = tevent_req_callback_data(subreq,
263                                             struct dnsupdate_service);
264         int ret;
265         int sys_errno;
266
267         service->nameupdate.spnreq = NULL;
268
269         ret = samba_runcmd_recv(subreq, &sys_errno);
270         TALLOC_FREE(subreq);
271         if (ret != 0) {
272                 service->nameupdate.status = map_nt_error_from_unix(sys_errno);
273         } else {
274                 service->nameupdate.status = NT_STATUS_OK;
275         }
276
277         if (!NT_STATUS_IS_OK(service->nameupdate.status)) {
278                 DEBUG(0,(__location__ ": Failed SPN update - %s\n",
279                          nt_errstr(service->nameupdate.status)));
280         } else {
281                 DEBUG(3,("Completed SPN update check OK\n"));
282         }
283 }
284
285 /*
286   called every 'dnsupdate:name interval' seconds
287  */
288 static void dnsupdate_check_names(struct dnsupdate_service *service)
289 {
290         const char * const *dns_update_command = lpcfg_dns_update_command(service->task->lp_ctx);
291         const char * const *spn_update_command = lpcfg_spn_update_command(service->task->lp_ctx);
292
293         /* kill any existing child */
294         TALLOC_FREE(service->nameupdate.subreq);
295
296         DEBUG(3,("Calling DNS name update script\n"));
297         service->nameupdate.subreq = samba_runcmd_send(service,
298                                                        service->task->event_ctx,
299                                                        timeval_current_ofs(20, 0),
300                                                        2, 0,
301                                                        dns_update_command,
302                                                        NULL);
303         if (service->nameupdate.subreq == NULL) {
304                 DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
305                 return;
306         }
307         tevent_req_set_callback(service->nameupdate.subreq,
308                                 dnsupdate_nameupdate_done,
309                                 service);
310
311         DEBUG(3,("Calling SPN name update script\n"));
312         service->nameupdate.spnreq = samba_runcmd_send(service,
313                                                        service->task->event_ctx,
314                                                        timeval_current_ofs(20, 0),
315                                                        2, 0,
316                                                        spn_update_command,
317                                                        NULL);
318         if (service->nameupdate.spnreq == NULL) {
319                 DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
320                 return;
321         }
322         tevent_req_set_callback(service->nameupdate.spnreq,
323                                 dnsupdate_spnupdate_done,
324                                 service);
325 }
326
327 static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service);
328
329 /*
330   called every 'dnsupdate:name interval' seconds
331  */
332 static void dnsupdate_nameupdate_handler_te(struct tevent_context *ev, struct tevent_timer *te,
333                                             struct timeval t, void *ptr)
334 {
335         struct dnsupdate_service *service = talloc_get_type(ptr, struct dnsupdate_service);
336
337         dnsupdate_check_names(service);
338         dnsupdate_nameupdate_schedule(service);
339 }
340
341
342 static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service)
343 {
344         service->nameupdate.te = tevent_add_timer(service->task->event_ctx, service,
345                                                   timeval_current_ofs(service->nameupdate.interval, 0),
346                                                   dnsupdate_nameupdate_handler_te, service);
347         NT_STATUS_HAVE_NO_MEMORY(service->nameupdate.te);
348         return NT_STATUS_OK;
349 }
350
351
352 struct dnsupdate_RODC_state {
353         struct irpc_message *msg;
354         struct dnsupdate_RODC *r;
355         char *tmp_path;
356         int fd;
357 };
358
359 static int dnsupdate_RODC_destructor(struct dnsupdate_RODC_state *st)
360 {
361         if (st->fd != -1) {
362                 close(st->fd);
363         }
364         unlink(st->tmp_path);
365         return 0;
366 }
367
368 /*
369   called when the DNS update has completed
370  */
371 static void dnsupdate_RODC_callback(struct tevent_req *req)
372 {
373         struct dnsupdate_RODC_state *st =
374                 tevent_req_callback_data(req,
375                                          struct dnsupdate_RODC_state);
376         int sys_errno;
377         int i, ret;
378
379         ret = samba_runcmd_recv(req, &sys_errno);
380         talloc_free(req);
381         if (ret != 0) {
382                 st->r->out.result = map_nt_error_from_unix(sys_errno);
383                 DEBUG(2,(__location__ ": RODC DNS Update failed: %s\n", nt_errstr(st->r->out.result)));
384         } else {
385                 st->r->out.result = NT_STATUS_OK;
386                 DEBUG(3,(__location__ ": RODC DNS Update OK\n"));
387         }
388
389         for (i=0; i<st->r->in.dns_names->count; i++) {
390                 st->r->out.dns_names->names[i].status = NT_STATUS_V(st->r->out.result);
391         }
392
393         irpc_send_reply(st->msg, NT_STATUS_OK);
394 }
395
396
397 /**
398  * Called when we get a RODC DNS update request from the netlogon
399  * rpc server
400  */
401 static NTSTATUS dnsupdate_dnsupdate_RODC(struct irpc_message *msg,
402                                          struct dnsupdate_RODC *r)
403 {
404         struct dnsupdate_service *s = talloc_get_type(msg->private_data,
405                                                       struct dnsupdate_service);
406         const char * const *dns_update_command = lpcfg_dns_update_command(s->task->lp_ctx);
407         struct dnsupdate_RODC_state *st;
408         struct tevent_req *req;
409         int i, ret;
410         struct GUID ntds_guid;
411         const char *site, *dnsdomain, *dnsforest, *ntdsguid, *hostname;
412         struct ldb_dn *sid_dn;
413         const char *attrs[] = { "dNSHostName", NULL };
414         struct ldb_result *res;
415
416         st = talloc_zero(msg, struct dnsupdate_RODC_state);
417         if (!st) {
418                 r->out.result = NT_STATUS_NO_MEMORY;
419                 return NT_STATUS_OK;
420         }
421
422         st->r = r;
423         st->msg = msg;
424
425         st->tmp_path = smbd_tmp_path(st, s->task->lp_ctx, "rodcdns.XXXXXX");
426         if (!st->tmp_path) {
427                 talloc_free(st);
428                 r->out.result = NT_STATUS_NO_MEMORY;
429                 return NT_STATUS_OK;
430         }
431
432         st->fd = mkstemp(st->tmp_path);
433         if (st->fd == -1) {
434                 DEBUG(0,("Unable to create a temporary file for RODC dnsupdate\n"));
435                 talloc_free(st);
436                 r->out.result = NT_STATUS_INTERNAL_DB_CORRUPTION;
437                 return NT_STATUS_OK;
438         }
439
440         talloc_set_destructor(st, dnsupdate_RODC_destructor);
441
442         sid_dn = ldb_dn_new_fmt(st, s->samdb, "<SID=%s>", dom_sid_string(st, r->in.dom_sid));
443         if (!sid_dn) {
444                 talloc_free(st);
445                 r->out.result = NT_STATUS_NO_MEMORY;
446                 return NT_STATUS_OK;
447         }
448
449         /* work out the site */
450         ret = samdb_find_site_for_computer(s->samdb, st, sid_dn, &site);
451         if (ret != LDB_SUCCESS) {
452                 DEBUG(2, (__location__ ": Unable to find site for computer %s\n",
453                           ldb_dn_get_linearized(sid_dn)));
454                 talloc_free(st);
455                 r->out.result = NT_STATUS_NO_SUCH_USER;
456                 return NT_STATUS_OK;
457         }
458
459         /* work out the ntdsguid */
460         ret = samdb_find_ntdsguid_for_computer(s->samdb, sid_dn, &ntds_guid);
461         ntdsguid = GUID_string(st, &ntds_guid);
462         if (ret != LDB_SUCCESS || !ntdsguid) {
463                 DEBUG(2, (__location__ ": Unable to find NTDS GUID for computer %s\n",
464                           ldb_dn_get_linearized(sid_dn)));
465                 talloc_free(st);
466                 r->out.result = NT_STATUS_NO_SUCH_USER;
467                 return NT_STATUS_OK;
468         }
469
470
471         /* find dnsdomain and dnsforest */
472         dnsdomain = lpcfg_realm(s->task->lp_ctx);
473         dnsforest = dnsdomain;
474
475         /* find the hostname */
476         ret = dsdb_search_dn(s->samdb, st, &res, sid_dn, attrs, 0);
477         if (ret == LDB_SUCCESS) {
478                 hostname = ldb_msg_find_attr_as_string(res->msgs[0], "dNSHostName", NULL);
479         }
480         if (ret != LDB_SUCCESS || !hostname) {
481                 DEBUG(2, (__location__ ": Unable to find NTDS GUID for computer %s\n",
482                           ldb_dn_get_linearized(sid_dn)));
483                 talloc_free(st);
484                 r->out.result = NT_STATUS_NO_SUCH_USER;
485                 return NT_STATUS_OK;
486         }
487
488
489         for (i=0; i<st->r->in.dns_names->count; i++) {
490                 struct NL_DNS_NAME_INFO *n = &r->in.dns_names->names[i];
491                 switch (n->type) {
492                 case NlDnsLdapAtSite:
493                         dprintf(st->fd, "SRV _ldap._tcp.%s._sites.%s. %s %u\n",
494                                 site, dnsdomain, hostname, n->port);
495                         break;
496                 case NlDnsGcAtSite:
497                         dprintf(st->fd, "SRV _ldap._tcp.%s._sites.gc._msdcs.%s. %s %u\n",
498                                 site, dnsdomain, hostname, n->port);
499                         break;
500                 case NlDnsDsaCname:
501                         dprintf(st->fd, "CNAME %s._msdcs.%s. %s\n",
502                                 ntdsguid, dnsforest, hostname);
503                         break;
504                 case NlDnsKdcAtSite:
505                         dprintf(st->fd, "SRV _kerberos._tcp.%s._sites.dc._msdcs.%s. %s %u\n",
506                                 site, dnsdomain, hostname, n->port);
507                         break;
508                 case NlDnsDcAtSite:
509                         dprintf(st->fd, "SRV _ldap._tcp.%s._sites.dc._msdcs.%s. %s %u\n",
510                                 site, dnsdomain, hostname, n->port);
511                         break;
512                 case NlDnsRfc1510KdcAtSite:
513                         dprintf(st->fd, "SRV _kerberos._tcp.%s._sites.%s. %s %u\n",
514                                 site, dnsdomain, hostname, n->port);
515                         break;
516                 case NlDnsGenericGcAtSite:
517                         dprintf(st->fd, "SRV _gc._tcp.%s._sites.%s. %s %u\n",
518                                 site, dnsforest, hostname, n->port);
519                         break;
520                 }
521         }
522
523         close(st->fd);
524         st->fd = -1;
525
526         DEBUG(3,("Calling RODC DNS name update script %s\n", st->tmp_path));
527         req = samba_runcmd_send(st,
528                                 s->task->event_ctx,
529                                 timeval_current_ofs(20, 0),
530                                 2, 0,
531                                 dns_update_command,
532                                 "--update-list",
533                                 st->tmp_path,
534                                 NULL);
535         NT_STATUS_HAVE_NO_MEMORY(req);
536
537         /* setup the callback */
538         tevent_req_set_callback(req, dnsupdate_RODC_callback, st);
539
540         msg->defer_reply = true;
541
542         return NT_STATUS_OK;
543 }
544
545 /*
546   startup the dns update task
547 */
548 static void dnsupdate_task_init(struct task_server *task)
549 {
550         NTSTATUS status;
551         struct dnsupdate_service *service;
552
553         if (lpcfg_server_role(task->lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
554                 /* not useful for non-DC */
555                 return;
556         }
557
558         task_server_set_title(task, "task[dnsupdate]");
559
560         service = talloc_zero(task, struct dnsupdate_service);
561         if (!service) {
562                 task_server_terminate(task, "dnsupdate_task_init: out of memory", true);
563                 return;
564         }
565         service->task           = task;
566         task->private_data      = service;
567
568         service->system_session_info = system_session(service->task->lp_ctx);
569         if (!service->system_session_info) {
570                 task_server_terminate(task,
571                                       "dnsupdate: Failed to obtain server credentials\n",
572                                       true);
573                 return;
574         }
575
576         service->samdb = samdb_connect(service, service->task->event_ctx, task->lp_ctx,
577                                        service->system_session_info, 0);
578         if (!service->samdb) {
579                 task_server_terminate(task, "dnsupdate: Failed to connect to local samdb\n",
580                                       true);
581                 return;
582         }
583
584         service->confupdate.interval    = lpcfg_parm_int(task->lp_ctx, NULL,
585                                                       "dnsupdate", "config interval", 60); /* in seconds */
586
587         service->nameupdate.interval    = lpcfg_parm_int(task->lp_ctx, NULL,
588                                                       "dnsupdate", "name interval", 600); /* in seconds */
589
590         dnsupdate_rebuild(service);
591         status = dnsupdate_confupdate_schedule(service);
592         if (!NT_STATUS_IS_OK(status)) {
593                 task_server_terminate(task, talloc_asprintf(task,
594                                       "dnsupdate: Failed to confupdate schedule: %s\n",
595                                                             nt_errstr(status)), true);
596                 return;
597         }
598
599         dnsupdate_check_names(service);
600         status = dnsupdate_nameupdate_schedule(service);
601         if (!NT_STATUS_IS_OK(status)) {
602                 task_server_terminate(task, talloc_asprintf(task,
603                                       "dnsupdate: Failed to nameupdate schedule: %s\n",
604                                                             nt_errstr(status)), true);
605                 return;
606         }
607
608         irpc_add_name(task->msg_ctx, "dnsupdate");
609
610         IRPC_REGISTER(task->msg_ctx, irpc, DNSUPDATE_RODC,
611                       dnsupdate_dnsupdate_RODC, service);
612
613         /* create the intial file */
614         dnsupdate_rebuild(service);
615
616 }
617
618 /*
619   register ourselves as a available server
620 */
621 NTSTATUS server_service_dnsupdate_init(void)
622 {
623         return register_server_service("dnsupdate", dnsupdate_task_init);
624 }