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/*
Unix SMB/CIFS mplementation.
DNS udpate service
Copyright (C) Andrew Tridgell 2009
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
this module auto-creates the named.conf.update file, which tells
bind9 what KRB5 principals it should accept for updates to our zone
*/
#include "includes.h"
#include "dsdb/samdb/samdb.h"
#include "auth/auth.h"
#include "smbd/service.h"
#include "lib/events/events.h"
#include "lib/messaging/irpc.h"
#include "lib/ldb/include/ldb_errors.h"
#include "param/param.h"
#include "system/filesys.h"
#include "lib/tevent/tevent.h"
struct dnsupdate_service {
struct task_server *task;
struct auth_session_info *system_session_info;
struct ldb_context *samdb;
struct {
uint32_t interval;
struct tevent_timer *te;
} periodic;
};
/*
called every dnsupdate:interval seconds
*/
static void dnsupdate_rebuild(struct dnsupdate_service *service)
{
int ret;
struct ldb_result *res;
const char *tmp_path, *path;
int fd, i;
const char *attrs[] = { "sAMAccountName", NULL };
const char *realm = lp_realm(service->task->lp_ctx);
TALLOC_CTX *tmp_ctx = talloc_new(service);
const char *rndc_cmd;
ret = ldb_search(service->samdb, tmp_ctx, &res, NULL, LDB_SCOPE_SUBTREE,
attrs, "(&(primaryGroupID=%u)(objectClass=computer))",
DOMAIN_RID_DCS);
if (ret != LDB_SUCCESS) {
DEBUG(0,(__location__ ": Unable to find DCs list - %s", ldb_errstring(service->samdb)));
talloc_free(tmp_ctx);
return;
}
path = lp_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "path");
if (path == NULL) {
path = private_path(tmp_ctx, service->task->lp_ctx, "named.conf.update");
}
tmp_path = talloc_asprintf(tmp_ctx, "%s.tmp", path);
if (path == NULL || tmp_path == NULL) {
DEBUG(0,(__location__ ": Unable to get paths"));
talloc_free(tmp_ctx);
return;
}
unlink(tmp_path);
fd = open(tmp_path, O_CREAT|O_TRUNC|O_WRONLY, 0444);
if (fd == -1) {
DEBUG(1,(__location__ ": Unable to open %s - %s\n", tmp_path, strerror(errno)));
talloc_free(tmp_ctx);
return;
}
dprintf(fd, "/* this file is auto-generated - do not edit */\n");
dprintf(fd, "update-policy {\n");
dprintf(fd, "\tgrant %s ms-self * A AAAA;\n", realm);
dprintf(fd, "\tgrant administrator@%s wildcard * A AAAA SRV CNAME TXT;\n", realm);
for (i=0; i<res->count; i++) {
const char *acctname;
acctname = ldb_msg_find_attr_as_string(res->msgs[i],
"sAMAccountName", NULL);
if (!acctname) continue;
dprintf(fd, "\tgrant %s@%s wildcard * A AAAA SRV CNAME;\n",
acctname, realm);
}
dprintf(fd, "};\n");
close(fd);
if (file_compare(tmp_path, path) == true) {
unlink(tmp_path);
talloc_free(tmp_ctx);
return;
}
if (rename(tmp_path, path) != 0) {
DEBUG(0,(__location__ ": Failed to rename %s to %s - %s\n",
tmp_path, path, strerror(errno)));
talloc_free(tmp_ctx);
return;
}
DEBUG(1,("Loaded new DNS update grant rules\n"));
rndc_cmd = lp_parm_string(service->task->lp_ctx, NULL, "dnsupdate", "rndc reload command");
if (!rndc_cmd) {
rndc_cmd = "/usr/sbin/rndc reload";
}
ret = system(rndc_cmd);
if (ret != 0) {
DEBUG(0,(__location__ ": Failed rndc reload command: '%s' - %d\n",
rndc_cmd, ret));
}
talloc_free(tmp_ctx);
}
static NTSTATUS dnsupdate_periodic_schedule(struct dnsupdate_service *service);
/*
called every dnsupdate:interval seconds
*/
static void dnsupdate_periodic_handler_te(struct tevent_context *ev, struct tevent_timer *te,
struct timeval t, void *ptr)
{
struct dnsupdate_service *service = talloc_get_type(ptr, struct dnsupdate_service);
dnsupdate_rebuild(service);
dnsupdate_periodic_schedule(service);
}
static NTSTATUS dnsupdate_periodic_schedule(struct dnsupdate_service *service)
{
service->periodic.te = tevent_add_timer(service->task->event_ctx, service,
timeval_current_ofs(service->periodic.interval, 0),
dnsupdate_periodic_handler_te, service);
NT_STATUS_HAVE_NO_MEMORY(service->periodic.te);
return NT_STATUS_OK;
}
/*
startup the dns update task
*/
static void dnsupdate_task_init(struct task_server *task)
{
NTSTATUS status;
struct dnsupdate_service *service;
if (lp_server_role(task->lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
/* not useful for non-DC */
return;
}
task_server_set_title(task, "task[dnsupdate]");
service = talloc_zero(task, struct dnsupdate_service);
if (!service) {
task_server_terminate(task, "dnsupdate_task_init: out of memory", true);
return;
}
service->task = task;
task->private_data = service;
service->system_session_info = system_session(service->task->lp_ctx);
if (!service->system_session_info) {
task_server_terminate(task,
"dnsupdate: Failed to obtain server credentials\n",
true);
return;
}
service->samdb = samdb_connect(service, service->task->event_ctx, task->lp_ctx,
service->system_session_info);
if (!service->samdb) {
task_server_terminate(task, "dnsupdate: Failed to connect to local samdb\n",
true);
return;
}
service->periodic.interval = lp_parm_int(task->lp_ctx, NULL,
"dnsupdate", "interval", 60); /* in seconds */
status = dnsupdate_periodic_schedule(service);
if (!NT_STATUS_IS_OK(status)) {
task_server_terminate(task, talloc_asprintf(task,
"dnsupdate: Failed to periodic schedule: %s\n",
nt_errstr(status)), true);
return;
}
irpc_add_name(task->msg_ctx, "dnsupdate");
/* create the intial file */
dnsupdate_rebuild(service);
}
/*
register ourselves as a available server
*/
NTSTATUS server_service_dnsupdate_init(void)
{
return register_server_service("dnsupdate", dnsupdate_task_init);
}
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