Start an 'NTP signing server' in Samba4.

I am modifying the ntp.org server to talk to this service, to sign
packets per MS-SNTP.

Andrew Bartlett
(This used to be commit 0c15385e6068d2f70ff11aa5837adbd6d78410ae)

2 files changed, 274 insertions, 0 deletions

diff --git a/source4/ntp_signd/config.mk b/source4/ntp_signd/config.mk
new file mode 100644
index 0000000000..e8d0530f62
--- /dev/null
+++ b/source4/ntp_signd/config.mk
@@ -0,0 +1,14 @@
+# NTP_SIGND server subsystem
+
+#######################
+# Start SUBSYSTEM NTP_signd
+[MODULE::NTP_SIGND]
+INIT_FUNCTION = server_service_ntp_signd_init
+SUBSYSTEM = smbd
+PRIVATE_DEPENDENCIES = \
+		SAMDB NDR_NTP_SIGND
+# End SUBSYSTEM NTP_SIGND
+#######################
+
+NTP_SIGND_OBJ_FILES = $(addprefix $(ntp_signd_srcdir)/, ntp_signd.o)
+
diff --git a/source4/ntp_signd/ntp_signd.c b/source4/ntp_signd/ntp_signd.c
new file mode 100644
index 0000000000..41a3df019a
--- /dev/null
+++ b/source4/ntp_signd/ntp_signd.c
@@ -0,0 +1,260 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   NTP packet signing server
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
+   Copyright (C) Andrew Tridgell	2005
+   Copyright (C) Stefan Metzmacher	2005
+
+   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/>.
+*/
+
+#include "includes.h"
+#include "smbd/service_task.h"
+#include "smbd/service.h"
+#include "smbd/service_stream.h"
+#include "smbd/process_model.h"
+#include "lib/stream/packet.h"
+#include "librpc/gen_ndr/ntp_signd.h"
+#include "param/param.h"
+#include "dsdb/samdb/samdb.h"
+#include "auth/auth.h"
+
+/*
+  top level context structure for the ntp_signd server
+*/
+struct ntp_signd_server {
+	struct task_server *task;
+	struct ldb_context *samdb;
+};
+
+/*
+  state of an open connection
+*/
+struct ntp_signd_connection {
+	/* stream connection we belong to */
+	struct stream_connection *conn;
+
+	/* the ntp_signd_server the connection belongs to */
+	struct ntp_signd_server *ntp_signd;
+
+	struct packet_context *packet;
+};
+
+static void ntp_signd_terminate_connection(struct ntp_signd_connection *ntp_signdconn, const char *reason)
+{
+	stream_terminate_connection(ntp_signdconn->conn, reason);
+}
+
+/*
+  receive a full packet on a NTP_SIGND connection
+*/
+static NTSTATUS ntp_signd_recv(void *private, DATA_BLOB blob)
+{
+	struct ntp_signd_connection *ntp_signdconn = talloc_get_type(private, 
+							     struct ntp_signd_connection);
+	NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
+	TALLOC_CTX *tmp_ctx = talloc_new(ntp_signdconn);
+	DATA_BLOB input, reply;
+	const struct dom_sid *domain_sid;
+	struct dom_sid *sid;
+	struct sign_request sign_request;
+	enum ndr_err_code ndr_err;
+	struct ldb_result *res;
+	const char *attrs[] = { "unicodePwd", NULL };
+
+	talloc_steal(tmp_ctx, blob.data);
+
+	input = data_blob_const(blob.data + 4, blob.length - 4); 
+
+	ndr_err = ndr_pull_struct_blob_all(input, tmp_ctx, 
+					   iconv_convenience,
+					   &sign_request,
+					   (ndr_pull_flags_fn_t)ndr_pull_sign_request);
+
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		DEBUG(1,("failed to parse ntp signing request\n"));
+		dump_data(1, input.data, input.length);
+		return ndr_map_error2ntstatus(ndr_err);
+	}
+
+	domain_sid = samdb_domain_sid(ntp_signdconn->ntp_signd->samdb);
+	if (!domain_sid) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+	
+	sid = dom_sid_add_rid(tmp_ctx, domain_sid, sign_request.key_id & 0x7FFFFFFF);
+	if (!sid) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	/* Sign packet */
+	ret = ldb_search_exp_format(ntp_signdconn->ntp_signd->samdb, tmp_ctx,
+				    &res, samdb_base_dn(ntp_signdconn->ntp_signd->samdb),
+				    LDB_SCOPE_SUBTREE, attrs, "(&(objectSid=%s)(objectClass=computer))");
+	if (ret != LDB_SUCCESS) {
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	if (res->count != 1) {
+		return NT_STATUS_NO_SUCH_USER;
+	}
+
+	/* Sign the NTP response with the unicodePwd */
+
+	/* Place it into the packet for the wire */
+
+	blob = data_blob_talloc(ntp_signdconn, NULL, reply.length + 4);
+	if (!blob.data) {
+		talloc_free(tmp_ctx);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	RSIVAL(blob.data, 0, reply.length);
+	memcpy(blob.data + 4, reply.data, reply.length);	
+
+	status = packet_send(ntp_signdconn->packet, blob);
+
+	/* the call isn't needed any more */
+	talloc_free(tmp_ctx);
+	return status;
+}
+
+/*
+  receive some data on a NTP_SIGND connection
+*/
+static void ntp_signd_recv_handler(struct stream_connection *conn, uint16_t flags)
+{
+	struct ntp_signd_connection *ntp_signdconn = talloc_get_type(conn->private, 
+							     struct ntp_signd_connection);
+	packet_recv(ntp_signdconn->packet);
+}
+
+/*
+  called on a tcp recv error
+*/
+static void ntp_signd_recv_error(void *private, NTSTATUS status)
+{
+	struct ntp_signd_connection *ntp_signdconn = talloc_get_type(private, struct ntp_signd_connection);
+	ntp_signd_terminate_connection(ntp_signdconn, nt_errstr(status));
+}
+
+/*
+  called when we can write to a connection
+*/
+static void ntp_signd_send(struct stream_connection *conn, uint16_t flags)
+{
+	struct ntp_signd_connection *ntp_signdconn = talloc_get_type(conn->private, 
+							     struct ntp_signd_connection);
+	packet_queue_run(ntp_signdconn->packet);
+}
+
+/*
+  called when we get a new connection
+*/
+static void ntp_signd_accept(struct stream_connection *conn)
+{
+	struct ntp_signd_server *ntp_signd = talloc_get_type(conn->private, struct ntp_signd_server);
+	struct ntp_signd_connection *ntp_signdconn;
+
+	ntp_signdconn = talloc_zero(conn, struct ntp_signd_connection);
+	if (!ntp_signdconn) {
+		stream_terminate_connection(conn, "ntp_signd_accept: out of memory");
+		return;
+	}
+	ntp_signdconn->conn	 = conn;
+	ntp_signdconn->ntp_signd	 = ntp_signd;
+	conn->private    = ntp_signdconn;
+
+	ntp_signdconn->packet = packet_init(ntp_signdconn);
+	if (ntp_signdconn->packet == NULL) {
+		ntp_signd_terminate_connection(ntp_signdconn, "ntp_signd_accept: out of memory");
+		return;
+	}
+	packet_set_private(ntp_signdconn->packet, ntp_signdconn);
+	packet_set_socket(ntp_signdconn->packet, conn->socket);
+	packet_set_callback(ntp_signdconn->packet, ntp_signd_recv);
+	packet_set_full_request(ntp_signdconn->packet, packet_full_request_u32);
+	packet_set_error_handler(ntp_signdconn->packet, ntp_signd_recv_error);
+	packet_set_event_context(ntp_signdconn->packet, conn->event.ctx);
+	packet_set_fde(ntp_signdconn->packet, conn->event.fde);
+	packet_set_serialise(ntp_signdconn->packet);
+}
+
+static const struct stream_server_ops ntp_signd_stream_ops = {
+	.name			= "ntp_signd",
+	.accept_connection	= ntp_signd_accept,
+	.recv_handler		= ntp_signd_recv_handler,
+	.send_handler		= ntp_signd_send
+};
+
+/*
+  startup the ntp_signd task
+*/
+static void ntp_signd_task_init(struct task_server *task)
+{
+	struct ntp_signd_server *ntp_signd;
+	NTSTATUS status;
+
+	const struct model_ops *model_ops;
+
+	const char *address = "/tmp/ux_demo";
+
+	/* within the ntp_signd task we want to be a single process, so
+	   ask for the single process model ops and pass these to the
+	   stream_setup_socket() call. */
+	model_ops = process_model_byname("single");
+	if (!model_ops) {
+		DEBUG(0,("Can't find 'single' process model_ops\n"));
+		return;
+	}
+
+	status = stream_setup_socket(ntp_signd->task->event_ctx, 
+				     ntp_signd->task->lp_ctx,
+				     model_ops, 
+				     &ntp_signd_stream_ops, 
+				     "unix", address, NULL,
+				     lp_socket_options(ntp_signd->task->lp_ctx), 
+				     ntp_signd);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("Failed to bind to %s - %s\n",
+			 address, nt_errstr(status)));
+		return;
+	}
+
+	task_server_set_title(task, "task[ntp_signd]");
+
+	ntp_signd = talloc(task, struct ntp_signd_server);
+	if (ntp_signd == NULL) {
+		task_server_terminate(task, "ntp_signd: out of memory");
+		return;
+	}
+
+	ntp_signd->task = task;
+
+	ntp_signd->samdb = samdb_connect(ntp_signd, task->event_ctx, task->lp_ctx, anonymous_session(ntp_signd, task->event_ctx, task->lp_ctx));
+	if (ntp_signd->samdb == NULL) {
+		task_server_terminate(task, "ntp_signd failed to open samdb");
+		return;
+	}
+
+}
+
+
+/* called at smbd startup - register ourselves as a server service */
+NTSTATUS server_service_ntp_signd_init(void)
+{
+	return register_server_service("ntp_signd", ntp_signd_task_init);
+}