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
  40 struct dnsupdate_service {
  41         struct task_server *task;
  42         struct auth_session_info *system_session_info;
  43         struct ldb_context *samdb;
  44
  45         /* status for periodic config file update */
  46         struct {
  47                 uint32_t interval;
  48                 struct tevent_timer *te;
  49                 struct tevent_req *subreq;
  50                 NTSTATUS status;
  51         } confupdate;
  52
  53         /* status for periodic DNS name check */
  54         struct {
  55                 uint32_t interval;
  56                 struct tevent_timer *te;
  57                 struct tevent_req *subreq;
  58                 NTSTATUS status;
  59         } nameupdate;
  60 };
  61
  62 /*
  63   called when rndc reload has finished
  64  */
  65 static void dnsupdate_rndc_done(struct tevent_req *subreq)
  66 {
  67         struct dnsupdate_service *service = tevent_req_callback_data(subreq,
  68                                             struct dnsupdate_service);
  69         int ret;
  70         int sys_errno;
  71
  72         service->confupdate.subreq = NULL;
  73
  74         ret = samba_runcmd_recv(subreq, &sys_errno);
  75         TALLOC_FREE(subreq);
  76         if (ret != 0) {
  77                 service->confupdate.status = map_nt_error_from_unix(sys_errno);
  78         } else {
  79                 service->confupdate.status = NT_STATUS_OK;
  80         }
  81
  82         if (!NT_STATUS_IS_OK(service->confupdate.status)) {
  83                 DEBUG(0,(__location__ ": Failed rndc update - %s\n",
  84                          nt_errstr(service->confupdate.status)));
  85         } else {
  86                 DEBUG(3,("Completed rndc reload OK\n"));
  87         }
  88 }
  89
  90 /*
  91   called every 'dnsupdate:conf interval' seconds
  92  */
  93 static void dnsupdate_rebuild(struct dnsupdate_service *service)
  94 {
  95         int ret;
  96         size_t size;
  97         struct ldb_result *res;
  98         const char *tmp_path, *path, *path_static;
  99         char *static_policies;
 100         int fd;
 101         unsigned int i;
 102         const char *attrs[] = { "sAMAccountName", NULL };
 103         const char *realm = lp_realm(service->task->lp_ctx);
 104         TALLOC_CTX *tmp_ctx = talloc_new(service);
 105         const char * const *rndc_command = lp_rndc_command(service->task->lp_ctx);
 106
 107         /* abort any pending script run */
 108         TALLOC_FREE(service->confupdate.subreq);
 109
 110         ret = ldb_search(service->samdb, tmp_ctx, &res, NULL, LDB_SCOPE_SUBTREE,
 111                          attrs, "(&(primaryGroupID=%u)(objectClass=computer))",
 112                          DOMAIN_RID_DCS);
 113         if (ret != LDB_SUCCESS) {
 114                 DEBUG(0,(__location__ ": Unable to find DCs list - %s", ldb_errstring(service->samdb)));
 115                 talloc_free(tmp_ctx);
 116                 return;
 117         }
 118
 119         path = lp_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "path");
 120         if (path == NULL) {
 121                 path = private_path(tmp_ctx, service->task->lp_ctx, "named.conf.update");
 122         }
 123
 124         path_static = lp_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "extra_static_grant_rules");
 125         if (path_static == NULL) {
 126                 path_static = private_path(tmp_ctx, service->task->lp_ctx, "named.conf.update.static");
 127         }
 128
 129         tmp_path = talloc_asprintf(tmp_ctx, "%s.tmp", path);
 130         if (path == NULL || tmp_path == NULL || path_static == NULL ) {
 131                 DEBUG(0,(__location__ ": Unable to get paths\n"));
 132                 talloc_free(tmp_ctx);
 133                 return;
 134         }
 135
 136         static_policies = file_load(path_static, &size, 0, tmp_ctx);
 137
 138         unlink(tmp_path);
 139         fd = open(tmp_path, O_CREAT|O_TRUNC|O_WRONLY, 0444);
 140         if (fd == -1) {
 141                 DEBUG(1,(__location__ ": Unable to open %s - %s\n", tmp_path, strerror(errno)));
 142                 talloc_free(tmp_ctx);
 143                 return;
 144         }
 145
 146         dprintf(fd, "/* this file is auto-generated - do not edit */\n");
 147         dprintf(fd, "update-policy {\n");
 148         if( static_policies != NULL ) {
 149                 dprintf(fd, "/* Start of static entries */\n");
 150                 dprintf(fd, "%s\n",static_policies);
 151                 dprintf(fd, "/* End of static entries */\n");
 152         }
 153         dprintf(fd, "\tgrant %s ms-self * A AAAA;\n", realm);
 154         dprintf(fd, "\tgrant administrator@%s wildcard * A AAAA SRV CNAME TXT;\n", realm);
 155
 156         for (i=0; i<res->count; i++) {
 157                 const char *acctname;
 158                 acctname = ldb_msg_find_attr_as_string(res->msgs[i],
 159                                                        "sAMAccountName", NULL);
 160                 if (!acctname) continue;
 161                 dprintf(fd, "\tgrant %s@%s wildcard * A AAAA SRV CNAME;\n",
 162                         acctname, realm);
 163         }
 164         dprintf(fd, "};\n");
 165         close(fd);
 166
 167
 168         if (NT_STATUS_IS_OK(service->confupdate.status) &&
 169             file_compare(tmp_path, path) == true) {
 170                 unlink(tmp_path);
 171                 talloc_free(tmp_ctx);
 172                 return;
 173         }
 174
 175         if (rename(tmp_path, path) != 0) {
 176                 DEBUG(0,(__location__ ": Failed to rename %s to %s - %s\n",
 177                          tmp_path, path, strerror(errno)));
 178                 talloc_free(tmp_ctx);
 179                 return;
 180         }
 181
 182         DEBUG(2,("Loading new DNS update grant rules\n"));
 183         service->confupdate.subreq = samba_runcmd_send(service,
 184                                                        service->task->event_ctx,
 185                                                        timeval_current_ofs(10, 0),
 186                                                        2, 0,
 187                                                        rndc_command,
 188                                                        "reload", NULL);
 189         if (service->confupdate.subreq == NULL) {
 190                 DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
 191                 talloc_free(tmp_ctx);
 192                 return;
 193         }
 194         tevent_req_set_callback(service->confupdate.subreq,
 195                                 dnsupdate_rndc_done,
 196                                 service);
 197
 198         talloc_free(tmp_ctx);
 199 }
 200
 201 static NTSTATUS dnsupdate_confupdate_schedule(struct dnsupdate_service *service);
 202
 203 /*
 204   called every 'dnsupdate:conf interval' seconds
 205  */
 206 static void dnsupdate_confupdate_handler_te(struct tevent_context *ev, struct tevent_timer *te,
 207                                           struct timeval t, void *ptr)
 208 {
 209         struct dnsupdate_service *service = talloc_get_type(ptr, struct dnsupdate_service);
 210
 211         dnsupdate_rebuild(service);
 212         dnsupdate_confupdate_schedule(service);
 213 }
 214
 215
 216 static NTSTATUS dnsupdate_confupdate_schedule(struct dnsupdate_service *service)
 217 {
 218         service->confupdate.te = tevent_add_timer(service->task->event_ctx, service,
 219                                                 timeval_current_ofs(service->confupdate.interval, 0),
 220                                                 dnsupdate_confupdate_handler_te, service);
 221         NT_STATUS_HAVE_NO_MEMORY(service->confupdate.te);
 222         return NT_STATUS_OK;
 223 }
 224
 225
 226 /*
 227   called when dns update script has finished
 228  */
 229 static void dnsupdate_nameupdate_done(struct tevent_req *subreq)
 230 {
 231         struct dnsupdate_service *service = tevent_req_callback_data(subreq,
 232                                             struct dnsupdate_service);
 233         int ret;
 234         int sys_errno;
 235
 236         service->nameupdate.subreq = NULL;
 237
 238         ret = samba_runcmd_recv(subreq, &sys_errno);
 239         TALLOC_FREE(subreq);
 240         if (ret != 0) {
 241                 service->nameupdate.status = map_nt_error_from_unix(sys_errno);
 242         } else {
 243                 service->nameupdate.status = NT_STATUS_OK;
 244         }
 245
 246         if (!NT_STATUS_IS_OK(service->nameupdate.status)) {
 247                 DEBUG(0,(__location__ ": Failed DNS update - %s\n",
 248                          nt_errstr(service->nameupdate.status)));
 249         } else {
 250                 DEBUG(3,("Completed DNS update check OK\n"));
 251         }
 252 }
 253
 254 /*
 255   called every 'dnsupdate:name interval' seconds
 256  */
 257 static void dnsupdate_check_names(struct dnsupdate_service *service)
 258 {
 259         const char * const *dns_update_command = lp_dns_update_command(service->task->lp_ctx);
 260
 261         /* kill any existing child */
 262         TALLOC_FREE(service->nameupdate.subreq);
 263
 264         DEBUG(3,("Calling DNS name update script\n"));
 265         service->nameupdate.subreq = samba_runcmd_send(service,
 266                                                        service->task->event_ctx,
 267                                                        timeval_current_ofs(10, 0),
 268                                                        2, 0,
 269                                                        dns_update_command,
 270                                                        NULL);
 271         if (service->nameupdate.subreq == NULL) {
 272                 DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
 273                 return;
 274         }
 275         tevent_req_set_callback(service->nameupdate.subreq,
 276                                 dnsupdate_nameupdate_done,
 277                                 service);
 278 }
 279
 280 static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service);
 281
 282 /*
 283   called every 'dnsupdate:name interval' seconds
 284  */
 285 static void dnsupdate_nameupdate_handler_te(struct tevent_context *ev, struct tevent_timer *te,
 286                                             struct timeval t, void *ptr)
 287 {
 288         struct dnsupdate_service *service = talloc_get_type(ptr, struct dnsupdate_service);
 289
 290         dnsupdate_check_names(service);
 291         dnsupdate_nameupdate_schedule(service);
 292 }
 293
 294
 295 static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service)
 296 {
 297         service->nameupdate.te = tevent_add_timer(service->task->event_ctx, service,
 298                                                   timeval_current_ofs(service->nameupdate.interval, 0),
 299                                                   dnsupdate_nameupdate_handler_te, service);
 300         NT_STATUS_HAVE_NO_MEMORY(service->nameupdate.te);
 301         return NT_STATUS_OK;
 302 }
 303
 304 /*
 305   startup the dns update task
 306 */
 307 static void dnsupdate_task_init(struct task_server *task)
 308 {
 309         NTSTATUS status;
 310         struct dnsupdate_service *service;
 311
 312         if (lp_server_role(task->lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
 313                 /* not useful for non-DC */
 314                 return;
 315         }
 316
 317         task_server_set_title(task, "task[dnsupdate]");
 318
 319         service = talloc_zero(task, struct dnsupdate_service);
 320         if (!service) {
 321                 task_server_terminate(task, "dnsupdate_task_init: out of memory", true);
 322                 return;
 323         }
 324         service->task           = task;
 325         task->private_data      = service;
 326
 327         service->system_session_info = system_session(service->task->lp_ctx);
 328         if (!service->system_session_info) {
 329                 task_server_terminate(task,
 330                                       "dnsupdate: Failed to obtain server credentials\n",
 331                                       true);
 332                 return;
 333         }
 334
 335         service->samdb = samdb_connect(service, service->task->event_ctx, task->lp_ctx,
 336                                        service->system_session_info);
 337         if (!service->samdb) {
 338                 task_server_terminate(task, "dnsupdate: Failed to connect to local samdb\n",
 339                                       true);
 340                 return;
 341         }
 342
 343         service->confupdate.interval    = lp_parm_int(task->lp_ctx, NULL,
 344                                                       "dnsupdate", "config interval", 60); /* in seconds */
 345
 346         service->nameupdate.interval    = lp_parm_int(task->lp_ctx, NULL,
 347                                                       "dnsupdate", "name interval", 600); /* in seconds */
 348
 349         dnsupdate_rebuild(service);
 350         status = dnsupdate_confupdate_schedule(service);
 351         if (!NT_STATUS_IS_OK(status)) {
 352                 task_server_terminate(task, talloc_asprintf(task,
 353                                       "dnsupdate: Failed to confupdate schedule: %s\n",
 354                                                             nt_errstr(status)), true);
 355                 return;
 356         }
 357
 358         dnsupdate_check_names(service);
 359         status = dnsupdate_nameupdate_schedule(service);
 360         if (!NT_STATUS_IS_OK(status)) {
 361                 task_server_terminate(task, talloc_asprintf(task,
 362                                       "dnsupdate: Failed to nameupdate schedule: %s\n",
 363                                                             nt_errstr(status)), true);
 364                 return;
 365         }
 366
 367         irpc_add_name(task->msg_ctx, "dnsupdate");
 368
 369         /* create the intial file */
 370         dnsupdate_rebuild(service);
 371
 372 }
 373
 374 /*
 375   register ourselves as a available server
 376 */
 377 NTSTATUS server_service_dnsupdate_init(void)
 378 {
 379         return register_server_service("dnsupdate", dnsupdate_task_init);
 380 }