source4/dsdb/dns/dns_update.c

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