s3:nmbd: implement a MAILSLOT => CLDAP proxy for NETLOGON_SAMLOGON requests

This will be used as part a the franky setup, where nmbd will forward
the MAILSLOT requests to the local samba4 CLDAP server.

"nmbd_proxy_logon:cldap_server = 127.0.0.1" would configure
and activate this feature.

metze

2 files changed, 244 insertions, 0 deletions

diff --git a/source3/nmbd/nmbd.c b/source3/nmbd/nmbd.c
index 3279466602..daf4c295a6 100644
--- a/source3/nmbd/nmbd.c
+++ b/source3/nmbd/nmbd.c
@@ -988,6 +988,12 @@ static bool open_sockets(bool isdaemon, int port)
 		exit(1);
 	}
 
+	if (!initialize_nmbd_proxy_logon()) {
+		DEBUG(0,("ERROR: Failed setup nmbd_proxy_logon.\n"));
+		kill_async_dns_child();
+		exit(1);
+	}
+
 	TALLOC_FREE(frame);
 	process();
 
diff --git a/source3/nmbd/nmbd_processlogon.c b/source3/nmbd/nmbd_processlogon.c
index 59a2ca405e..8173337da0 100644
--- a/source3/nmbd/nmbd_processlogon.c
+++ b/source3/nmbd/nmbd_processlogon.c
@@ -24,6 +24,9 @@
 */
 
 #include "includes.h"
+#include "../libcli/netlogon.h"
+#include "../libcli/cldap/cldap.h"
+#include "../lib/tsocket/tsocket.h"
 
 struct sam_database_info {
         uint32 index;
@@ -65,6 +68,235 @@ static void delayed_init_logon_handler(struct event_context *event_ctx,
 	TALLOC_FREE(te);
 }
 
+struct nmbd_proxy_logon_context {
+	struct cldap_socket *cldap_sock;
+};
+
+static struct nmbd_proxy_logon_context *global_nmbd_proxy_logon;
+
+bool initialize_nmbd_proxy_logon(void)
+{
+	const char *cldap_server = lp_parm_const_string(-1, "nmbd_proxy_logon",
+						        "cldap_server", NULL);
+	struct nmbd_proxy_logon_context *ctx;
+	NTSTATUS status;
+	struct in_addr addr;
+	char addrstr[INET_ADDRSTRLEN];
+	const char *server_str;
+	int ret;
+	struct tsocket_address *server_addr;
+
+	if (!cldap_server) {
+		return true;
+	}
+
+	addr = interpret_addr2(cldap_server);
+	server_str = inet_ntop(AF_INET, &addr,
+			     addrstr, sizeof(addrstr));
+	if (!server_str || strcmp("0.0.0.0", server_str) == 0) {
+		DEBUG(0,("Failed to resolve[%s] for nmbd_proxy_logon\n",
+			 cldap_server));
+		return false;
+	}
+
+	ctx = talloc_zero(nmbd_event_context(),
+			  struct nmbd_proxy_logon_context);
+	if (!ctx) {
+		return false;
+	}
+
+	ret = tsocket_address_inet_from_strings(ctx, "ipv4",
+						server_str, LDAP_PORT,
+						&server_addr);
+	if (ret != 0) {
+		TALLOC_FREE(ctx);
+		status = map_nt_error_from_unix(errno);
+		DEBUG(0,("Failed to create cldap tsocket_address for %s - %s\n",
+			 server_str, nt_errstr(status)));
+		return false;
+	}
+
+	/* we create a connected udp socket */
+	status = cldap_socket_init(ctx, nmbd_event_context(), NULL,
+				   server_addr, &ctx->cldap_sock);
+	TALLOC_FREE(server_addr);
+	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(ctx);
+		DEBUG(0,("failed to create cldap socket for %s: %s\n",
+			server_str, nt_errstr(status)));
+		return false;
+	}
+
+	global_nmbd_proxy_logon = ctx;
+	return true;
+}
+
+struct nmbd_proxy_logon_state {
+	struct in_addr local_ip;
+	struct packet_struct *p;
+	const char *remote_name;
+	uint8_t remote_name_type;
+	const char *remote_mailslot;
+	struct nbt_netlogon_packet req;
+	struct nbt_netlogon_response resp;
+	struct cldap_netlogon io;
+};
+
+static int nmbd_proxy_logon_state_destructor(struct nmbd_proxy_logon_state *s)
+{
+	s->p->locked = false;
+	free_packet(s->p);
+	return 0;
+}
+
+static void nmbd_proxy_logon_done(struct tevent_req *subreq);
+
+static void nmbd_proxy_logon(struct nmbd_proxy_logon_context *ctx,
+			     struct in_addr local_ip,
+			     struct packet_struct *p,
+			     uint8_t *buf,
+			     uint32_t len)
+{
+	struct nmbd_proxy_logon_state *state;
+	enum ndr_err_code ndr_err;
+	DATA_BLOB blob = data_blob_const(buf, len);
+	const char *computer_name = NULL;
+	const char *mailslot_name = NULL;
+	const char *user_name = NULL;
+	const char *domain_sid = NULL;
+	uint32_t acct_control = 0;
+	uint32_t nt_version = 0;
+	struct tevent_req *subreq;
+	fstring source_name;
+	struct dgram_packet *dgram = &p->packet.dgram;
+
+	state = TALLOC_ZERO_P(ctx, struct nmbd_proxy_logon_state);
+	if (!state) {
+		DEBUG(0,("failed to allocate nmbd_proxy_logon_state\n"));
+		return;
+	}
+
+	pull_ascii_nstring(source_name, sizeof(source_name), dgram->source_name.name);
+	state->remote_name = talloc_strdup(state, source_name);
+	state->remote_name_type = dgram->source_name.name_type,
+	state->local_ip = local_ip;
+	state->p = p;
+
+	ndr_err = ndr_pull_struct_blob(
+		&blob, state, NULL, &state->req,
+		(ndr_pull_flags_fn_t)ndr_pull_nbt_netlogon_packet);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		NTSTATUS status = ndr_map_error2ntstatus(ndr_err);
+		DEBUG(0,("failed parse nbt_letlogon_packet: %s\n",
+			nt_errstr(status)));
+		TALLOC_FREE(state);
+		return;
+	}
+
+	if (DEBUGLEVEL >= 10) {
+		DEBUG(10, ("nmbd_proxy_logon:\n"));
+		NDR_PRINT_DEBUG(nbt_netlogon_packet, &state->req);
+	}
+
+	switch (state->req.command) {
+	case LOGON_SAM_LOGON_REQUEST:
+		computer_name	= state->req.req.logon.computer_name;
+		user_name	= state->req.req.logon.user_name;
+		mailslot_name	= state->req.req.logon.mailslot_name;
+		acct_control	= state->req.req.logon.acct_control;
+		if (state->req.req.logon.sid_size > 0) {
+			domain_sid = dom_sid_string(state,
+						    &state->req.req.logon.sid);
+			if (!domain_sid) {
+				DEBUG(0,("failed to get a string for sid\n"));
+				TALLOC_FREE(state);
+				return;
+			}
+		}
+		nt_version	= state->req.req.logon.nt_version;
+		break;
+
+	default:
+		/* this can't happen as the caller already checks the command */
+		break;
+	}
+
+	state->remote_mailslot = mailslot_name;
+
+	if (user_name && strlen(user_name) == 0) {
+		user_name = NULL;
+	}
+
+	if (computer_name && strlen(computer_name) == 0) {
+		computer_name = NULL;
+	}
+
+	/*
+	 * as the socket is connected,
+	 * we don't need to specify the destination
+	 */
+	state->io.in.dest_address	= NULL;
+	state->io.in.dest_port		= 0;
+	state->io.in.realm		= NULL;
+	state->io.in.host		= computer_name;
+	state->io.in.user		= user_name;
+	state->io.in.domain_guid	= NULL;
+	state->io.in.domain_sid		= domain_sid;
+	state->io.in.acct_control	= acct_control;
+	state->io.in.version		= nt_version;
+	state->io.in.map_response	= false;
+
+	subreq = cldap_netlogon_send(state,
+				     ctx->cldap_sock,
+				     &state->io);
+	if (!subreq) {
+		DEBUG(0,("failed to send cldap netlogon call\n"));
+		TALLOC_FREE(state);
+		return;
+	}
+	tevent_req_set_callback(subreq, nmbd_proxy_logon_done, state);
+
+	/* we reply async */
+	state->p->locked = true;
+	talloc_set_destructor(state, nmbd_proxy_logon_state_destructor);
+}
+
+static void nmbd_proxy_logon_done(struct tevent_req *subreq)
+{
+	struct nmbd_proxy_logon_state *state =
+		tevent_req_callback_data(subreq,
+		struct nmbd_proxy_logon_state);
+	NTSTATUS status;
+	DATA_BLOB response;
+
+	status = cldap_netlogon_recv(subreq, NULL, state, &state->io);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("failed to recv cldap netlogon call: %s\n",
+			nt_errstr(status)));
+		TALLOC_FREE(state);
+		return;
+	}
+
+	status = push_netlogon_samlogon_response(&response, state, NULL,
+						 &state->io.out.netlogon);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0,("failed to push netlogon_samlogon_response: %s\n",
+			nt_errstr(status)));
+		TALLOC_FREE(state);
+		return;
+	}
+
+	send_mailslot(true, state->remote_mailslot,
+		      (char *)response.data, response.length,
+		      global_myname(), 0x0,
+		      state->remote_name,
+		      state->remote_name_type,
+		      state->p->ip,
+		      state->local_ip,
+		      state->p->port);
+	TALLOC_FREE(state);
+}
+
 /****************************************************************************
 Process a domain logon packet
 **************************************************************************/
@@ -318,6 +550,12 @@ reporting %s domain %s 0x%x ntversion=%x lm_nt token=%x lm_20 token=%x\n",
 				char *q = buf + 2;
 				fstring asccomp;
 
+				if (global_nmbd_proxy_logon) {
+					nmbd_proxy_logon(global_nmbd_proxy_logon,
+							 ip, p, (uint8_t *)buf, len);
+					return;
+				}
+
 				q += 2;
 
 				if (PTR_DIFF(q, buf) >= len) {