1 files changed, 464 insertions, 0 deletions

diff --git a/source4/dsdb/dns/dns_update.c b/source4/dsdb/dns/dns_update.c
new file mode 100644
index 0000000..dd94564
--- /dev/null
+++ b/source4/dsdb/dns/dns_update.c
@@ -0,0 +1,464 @@
+/*
+   Unix SMB/CIFS Implementation.
+
+   DNS update 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
+
+  It also uses the samba_dnsupdate script to auto-create the right DNS
+  names for ourselves as a DC in the domain, using TSIG-GSS
+ */
+
+#include "includes.h"
+#include "dsdb/samdb/samdb.h"
+#include "auth/auth.h"
+#include "samba/service.h"
+#include "lib/messaging/irpc.h"
+#include "param/param.h"
+#include "system/filesys.h"
+#include "dsdb/common/util.h"
+#include "libcli/composite/composite.h"
+#include "libcli/security/dom_sid.h"
+#include "librpc/gen_ndr/ndr_irpc.h"
+#include "libds/common/roles.h"
+
+NTSTATUS server_service_dnsupdate_init(TALLOC_CTX *);
+
+struct dnsupdate_service {
+	struct task_server *task;
+	struct auth_session_info *system_session_info;
+	struct ldb_context *samdb;
+
+	/* status for periodic config file update */
+	struct {
+		uint32_t interval;
+		struct tevent_timer *te;
+		struct tevent_req *subreq;
+		NTSTATUS status;
+	} confupdate;
+
+	/* status for periodic DNS name check */
+	struct {
+		uint32_t interval;
+		struct tevent_timer *te;
+		struct tevent_req *subreq;
+		struct tevent_req *spnreq;
+		NTSTATUS status;
+	} nameupdate;
+};
+
+/*
+  called when dns update script has finished
+ */
+static void dnsupdate_nameupdate_done(struct tevent_req *subreq)
+{
+	struct dnsupdate_service *service = tevent_req_callback_data(subreq,
+					    struct dnsupdate_service);
+	int ret;
+	int sys_errno;
+
+	service->nameupdate.subreq = NULL;
+
+	ret = samba_runcmd_recv(subreq, &sys_errno);
+	TALLOC_FREE(subreq);
+
+	if (ret != 0) {
+		DBG_ERR("Failed DNS update with exit code %d\n",
+			sys_errno);
+	} else {
+		DEBUG(3,("Completed DNS update check OK\n"));
+	}
+}
+
+
+/*
+  called when spn update script has finished
+ */
+static void dnsupdate_spnupdate_done(struct tevent_req *subreq)
+{
+	struct dnsupdate_service *service = tevent_req_callback_data(subreq,
+					    struct dnsupdate_service);
+	int ret;
+	int sys_errno;
+
+	service->nameupdate.spnreq = NULL;
+
+	ret = samba_runcmd_recv(subreq, &sys_errno);
+	TALLOC_FREE(subreq);
+	if (ret != 0) {
+		DEBUG(0,(__location__ ": Failed SPN update - with error code %d\n",
+			 sys_errno));
+	} else {
+		DEBUG(3,("Completed SPN update check OK\n"));
+	}
+}
+
+/*
+  called every 'dnsupdate:name interval' seconds
+ */
+static void dnsupdate_check_names(struct dnsupdate_service *service)
+{
+	const char * const *dns_update_command = lpcfg_dns_update_command(service->task->lp_ctx);
+	const char * const *spn_update_command = lpcfg_spn_update_command(service->task->lp_ctx);
+
+	/* kill any existing child */
+	TALLOC_FREE(service->nameupdate.subreq);
+
+	DEBUG(3,("Calling DNS name update script\n"));
+	service->nameupdate.subreq = samba_runcmd_send(service,
+						       service->task->event_ctx,
+						       timeval_current_ofs(20, 0),
+						       2, 0,
+						       dns_update_command,
+						       NULL);
+	if (service->nameupdate.subreq == NULL) {
+		DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
+		return;
+	}
+	tevent_req_set_callback(service->nameupdate.subreq,
+				dnsupdate_nameupdate_done,
+				service);
+
+	DEBUG(3,("Calling SPN name update script\n"));
+	service->nameupdate.spnreq = samba_runcmd_send(service,
+						       service->task->event_ctx,
+						       timeval_current_ofs(20, 0),
+						       2, 0,
+						       spn_update_command,
+						       NULL);
+	if (service->nameupdate.spnreq == NULL) {
+		DEBUG(0,(__location__ ": samba_runcmd_send() failed with no memory\n"));
+		return;
+	}
+	tevent_req_set_callback(service->nameupdate.spnreq,
+				dnsupdate_spnupdate_done,
+				service);
+}
+
+static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service);
+
+/*
+  called every 'dnsupdate:name interval' seconds
+ */
+static void dnsupdate_nameupdate_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_check_names(service);
+	dnsupdate_nameupdate_schedule(service);
+}
+
+
+static NTSTATUS dnsupdate_nameupdate_schedule(struct dnsupdate_service *service)
+{
+	service->nameupdate.te = tevent_add_timer(service->task->event_ctx, service,
+						  timeval_current_ofs(service->nameupdate.interval, 0),
+						  dnsupdate_nameupdate_handler_te, service);
+	NT_STATUS_HAVE_NO_MEMORY(service->nameupdate.te);
+	return NT_STATUS_OK;
+}
+
+
+struct dnsupdate_RODC_state {
+	struct irpc_message *msg;
+	struct dnsupdate_RODC *r;
+	char *tmp_path;
+	char *tmp_path2;
+	int fd;
+};
+
+static int dnsupdate_RODC_destructor(struct dnsupdate_RODC_state *st)
+{
+	if (st->fd != -1) {
+		close(st->fd);
+	}
+	unlink(st->tmp_path);
+	if (st->tmp_path2 != NULL) {
+		unlink(st->tmp_path2);
+	}
+	return 0;
+}
+
+/*
+  called when the DNS update has completed
+ */
+static void dnsupdate_RODC_callback(struct tevent_req *req)
+{
+	struct dnsupdate_RODC_state *st =
+		tevent_req_callback_data(req,
+					 struct dnsupdate_RODC_state);
+	int sys_errno;
+	int i, ret;
+
+	ret = samba_runcmd_recv(req, &sys_errno);
+	talloc_free(req);
+	if (ret != 0) {
+		st->r->out.result = map_nt_error_from_unix_common(sys_errno);
+		DEBUG(2,(__location__ ": RODC DNS Update failed: %s\n", nt_errstr(st->r->out.result)));
+	} else {
+		st->r->out.result = NT_STATUS_OK;
+		DEBUG(3,(__location__ ": RODC DNS Update OK\n"));
+	}
+
+	for (i=0; i<st->r->in.dns_names->count; i++) {
+		st->r->out.dns_names->names[i].status = NT_STATUS_V(st->r->out.result);
+	}
+
+	irpc_send_reply(st->msg, NT_STATUS_OK);
+}
+
+
+/**
+ * Called when we get a RODC DNS update request from the netlogon
+ * rpc server
+ */
+static NTSTATUS dnsupdate_dnsupdate_RODC(struct irpc_message *msg,
+					 struct dnsupdate_RODC *r)
+{
+	struct dnsupdate_service *s = talloc_get_type(msg->private_data,
+						      struct dnsupdate_service);
+	const char * const *dns_update_command = lpcfg_dns_update_command(s->task->lp_ctx);
+	struct dnsupdate_RODC_state *st;
+	struct tevent_req *req;
+	int i, ret;
+	struct GUID ntds_guid;
+	const char *site, *dnsdomain, *dnsforest, *ntdsguid;
+	const char *hostname = NULL;
+	struct ldb_dn *sid_dn;
+	const char *attrs[] = { "dNSHostName", NULL };
+	struct ldb_result *res;
+
+	st = talloc_zero(msg, struct dnsupdate_RODC_state);
+	if (!st) {
+		r->out.result = NT_STATUS_NO_MEMORY;
+		return NT_STATUS_OK;
+	}
+
+	st->r = r;
+	st->msg = msg;
+
+	st->tmp_path = smbd_tmp_path(st, s->task->lp_ctx, "rodcdns.XXXXXX");
+	if (!st->tmp_path) {
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_MEMORY;
+		return NT_STATUS_OK;
+	}
+
+	st->fd = mkstemp(st->tmp_path);
+	if (st->fd == -1) {
+		DEBUG(0,("Unable to create a temporary file for RODC dnsupdate\n"));
+		talloc_free(st);
+		r->out.result = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		return NT_STATUS_OK;
+	}
+
+	talloc_set_destructor(st, dnsupdate_RODC_destructor);
+
+	st->tmp_path2 = talloc_asprintf(st, "%s.cache", st->tmp_path);
+	if (!st->tmp_path2) {
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_MEMORY;
+		return NT_STATUS_OK;
+	}
+
+	sid_dn = ldb_dn_new_fmt(st, s->samdb, "<SID=%s>", dom_sid_string(st, r->in.dom_sid));
+	if (!sid_dn) {
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_MEMORY;
+		return NT_STATUS_OK;
+	}
+
+	/* work out the site */
+	ret = samdb_find_site_for_computer(s->samdb, st, sid_dn, &site);
+	if (ret != LDB_SUCCESS) {
+		DEBUG(2, (__location__ ": Unable to find site for computer %s\n",
+			  ldb_dn_get_linearized(sid_dn)));
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_SUCH_USER;
+		return NT_STATUS_OK;
+	}
+
+	/* work out the ntdsguid */
+	ret = samdb_find_ntdsguid_for_computer(s->samdb, sid_dn, &ntds_guid);
+	ntdsguid = GUID_string(st, &ntds_guid);
+	if (ret != LDB_SUCCESS || !ntdsguid) {
+		DEBUG(2, (__location__ ": Unable to find NTDS GUID for computer %s\n",
+			  ldb_dn_get_linearized(sid_dn)));
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_SUCH_USER;
+		return NT_STATUS_OK;
+	}
+
+
+	/* find dnsdomain and dnsforest */
+	dnsdomain = lpcfg_dnsdomain(s->task->lp_ctx);
+	dnsforest = dnsdomain;
+
+	/* find the hostname */
+	ret = dsdb_search_dn(s->samdb, st, &res, sid_dn, attrs, 0);
+	if (ret == LDB_SUCCESS) {
+		hostname = ldb_msg_find_attr_as_string(res->msgs[0], "dNSHostName", NULL);
+	}
+	if (ret != LDB_SUCCESS || !hostname) {
+		DEBUG(2, (__location__ ": Unable to find NTDS GUID for computer %s\n",
+			  ldb_dn_get_linearized(sid_dn)));
+		talloc_free(st);
+		r->out.result = NT_STATUS_NO_SUCH_USER;
+		return NT_STATUS_OK;
+	}
+
+	for (i=0; i<st->r->in.dns_names->count; i++) {
+		struct NL_DNS_NAME_INFO *n = &r->in.dns_names->names[i];
+		switch (n->type) {
+		case NlDnsLdapAtSite:
+			dprintf(st->fd, "SRV _ldap._tcp.%s._sites.%s %s %u\n",
+				site, dnsdomain, hostname, n->port);
+			break;
+		case NlDnsGcAtSite:
+			dprintf(st->fd, "SRV _ldap._tcp.%s._sites.gc._msdcs.%s %s %u\n",
+				site, dnsdomain, hostname, n->port);
+			break;
+		case NlDnsDsaCname:
+			dprintf(st->fd, "CNAME %s._msdcs.%s %s\n",
+				ntdsguid, dnsforest, hostname);
+			break;
+		case NlDnsKdcAtSite:
+			dprintf(st->fd, "SRV _kerberos._tcp.%s._sites.dc._msdcs.%s %s %u\n",
+				site, dnsdomain, hostname, n->port);
+			break;
+		case NlDnsDcAtSite:
+			dprintf(st->fd, "SRV _ldap._tcp.%s._sites.dc._msdcs.%s %s %u\n",
+				site, dnsdomain, hostname, n->port);
+			break;
+		case NlDnsRfc1510KdcAtSite:
+			dprintf(st->fd, "SRV _kerberos._tcp.%s._sites.%s %s %u\n",
+				site, dnsdomain, hostname, n->port);
+			break;
+		case NlDnsGenericGcAtSite:
+			dprintf(st->fd, "SRV _gc._tcp.%s._sites.%s %s %u\n",
+				site, dnsforest, hostname, n->port);
+			break;
+		}
+	}
+
+	close(st->fd);
+	st->fd = -1;
+
+	DEBUG(3,("Calling RODC DNS name update script %s\n", st->tmp_path));
+	req = samba_runcmd_send(st,
+				s->task->event_ctx,
+				timeval_current_ofs(20, 0),
+				2, 0,
+				dns_update_command,
+				"--update-list",
+				st->tmp_path,
+				"--update-cache",
+				st->tmp_path2,
+				NULL);
+	NT_STATUS_HAVE_NO_MEMORY(req);
+
+	/* setup the callback */
+	tevent_req_set_callback(req, dnsupdate_RODC_callback, st);
+
+	msg->defer_reply = true;
+
+	return NT_STATUS_OK;
+}
+
+/*
+  startup the dns update task
+*/
+static NTSTATUS dnsupdate_task_init(struct task_server *task)
+{
+	NTSTATUS status;
+	struct dnsupdate_service *service;
+
+	if (lpcfg_server_role(task->lp_ctx) != ROLE_ACTIVE_DIRECTORY_DC) {
+		/* not useful for non-DC */
+		return NT_STATUS_INVALID_DOMAIN_ROLE;
+	}
+
+	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 NT_STATUS_NO_MEMORY;
+	}
+	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 NT_STATUS_UNSUCCESSFUL;
+	}
+
+	service->samdb = samdb_connect(service,
+				       service->task->event_ctx,
+				       task->lp_ctx,
+				       service->system_session_info,
+				       NULL,
+				       0);
+	if (!service->samdb) {
+		task_server_terminate(task, "dnsupdate: Failed to connect to local samdb\n",
+				      true);
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	service->nameupdate.interval	= lpcfg_parm_int(task->lp_ctx, NULL,
+						      "dnsupdate", "name interval", 600); /* in seconds */
+
+	dnsupdate_check_names(service);
+	status = dnsupdate_nameupdate_schedule(service);
+	if (!NT_STATUS_IS_OK(status)) {
+		task_server_terminate(task, talloc_asprintf(task,
+				      "dnsupdate: Failed to nameupdate schedule: %s\n",
+							    nt_errstr(status)), true);
+		return status;
+	}
+
+	irpc_add_name(task->msg_ctx, "dnsupdate");
+
+	IRPC_REGISTER(task->msg_ctx, irpc, DNSUPDATE_RODC,
+		      dnsupdate_dnsupdate_RODC, service);
+
+	return NT_STATUS_OK;
+
+}
+
+/*
+  register ourselves as a available server
+*/
+NTSTATUS server_service_dnsupdate_init(TALLOC_CTX *ctx)
+{
+	static const struct service_details details = {
+		.inhibit_fork_on_accept = true,
+		.inhibit_pre_fork = true,
+		.task_init = dnsupdate_task_init,
+		.post_fork = NULL
+	};
+	return register_server_service(ctx, "dnsupdate", &details);
+}