Add unique IP address binding for client connections (EPM and ncacn_ip_tcp levels)

This allows for binding strings like this:

  ncacn_ip_tcp:host[localaddress=192.168.2.1,seal]

which will force the connection to be locally bound to the specified
IP address

Signed-off-by: Andrew Tridgell <tridge@samba.org>

6 files changed, 34 insertions, 7 deletions

diff --git a/source4/librpc/rpc/dcerpc.h b/source4/librpc/rpc/dcerpc.h
index b77628d8d7..b5062a55e3 100644
--- a/source4/librpc/rpc/dcerpc.h
+++ b/source4/librpc/rpc/dcerpc.h
@@ -181,6 +181,9 @@ struct dcerpc_pipe {
 /* use NDR64 transport */
 #define DCERPC_NDR64                   (1<<21)
 
+/* specify binding interface */
+#define	DCERPC_LOCALADDRESS            (1<<22)
+
 /* this describes a binding to a particular transport/pipe */
 struct dcerpc_binding {
 	enum dcerpc_transport_t transport;
@@ -189,6 +192,7 @@ struct dcerpc_binding {
 	const char *target_hostname;
 	const char *endpoint;
 	const char **options;
+	const char *localaddress;
 	uint32_t flags;
 	uint32_t assoc_group_id;
 };
diff --git a/source4/librpc/rpc/dcerpc_connect.c b/source4/librpc/rpc/dcerpc_connect.c
index 7779d31f99..0f3a86256c 100644
--- a/source4/librpc/rpc/dcerpc_connect.c
+++ b/source4/librpc/rpc/dcerpc_connect.c
@@ -276,6 +276,7 @@ static NTSTATUS dcerpc_pipe_connect_ncacn_np_smb2_recv(struct composite_context
 
 struct pipe_ip_tcp_state {
 	struct dcerpc_pipe_connect io;
+	const char *localaddr;
 	const char *host;
 	const char *target_hostname;
 	uint32_t port;
@@ -319,13 +320,14 @@ static struct composite_context* dcerpc_pipe_connect_ncacn_ip_tcp_send(TALLOC_CT
 
 	/* store input parameters in state structure */
 	s->io               = *io;
+	s->localaddr        = talloc_reference(c, io->binding->localaddress);
 	s->host             = talloc_reference(c, io->binding->host);
 	s->target_hostname  = talloc_reference(c, io->binding->target_hostname);
                              /* port number is a binding endpoint here */
 	s->port             = atoi(io->binding->endpoint);   
 
 	/* send pipe open request on tcp/ip */
-	pipe_req = dcerpc_pipe_open_tcp_send(s->io.pipe->conn, s->host, s->target_hostname, 
+	pipe_req = dcerpc_pipe_open_tcp_send(s->io.pipe->conn, s->localaddr, s->host, s->target_hostname,
 					     s->port, io->resolve_ctx);
 	composite_continue(c, pipe_req, continue_pipe_open_ncacn_ip_tcp, c);
 	return c;
diff --git a/source4/librpc/rpc/dcerpc_secondary.c b/source4/librpc/rpc/dcerpc_secondary.c
index 5f355a5937..65466e45e0 100644
--- a/source4/librpc/rpc/dcerpc_secondary.c
+++ b/source4/librpc/rpc/dcerpc_secondary.c
@@ -102,6 +102,7 @@ _PUBLIC_ struct composite_context* dcerpc_secondary_connection_send(struct dcerp
 		}
 
 		pipe_tcp_req = dcerpc_pipe_open_tcp_send(s->pipe2->conn,
+							 s->binding->localaddress,
 							 s->peer_addr->addr,
 							 s->binding->target_hostname,
 							 atoi(s->binding->endpoint),
diff --git a/source4/librpc/rpc/dcerpc_sock.c b/source4/librpc/rpc/dcerpc_sock.c
index d8bd6d2938..4ab8c35091 100644
--- a/source4/librpc/rpc/dcerpc_sock.c
+++ b/source4/librpc/rpc/dcerpc_sock.c
@@ -228,6 +228,7 @@ struct pipe_open_socket_state {
 	struct dcerpc_connection *conn;
 	struct socket_context *socket_ctx;
 	struct sock_private *sock;
+	struct socket_address *localaddr;
 	struct socket_address *server;
 	const char *target_hostname;
 	enum dcerpc_transport_t transport;
@@ -305,6 +306,7 @@ static void continue_socket_connect(struct composite_context *ctx)
 
 static struct composite_context *dcerpc_pipe_open_socket_send(TALLOC_CTX *mem_ctx,
 						       struct dcerpc_connection *cn,
+						       struct socket_address *localaddr,
 						       struct socket_address *server,
 						       const char *target_hostname,
 						       const char *full_path,
@@ -323,6 +325,10 @@ static struct composite_context *dcerpc_pipe_open_socket_send(TALLOC_CTX *mem_ct
 
 	s->conn      = cn;
 	s->transport = transport;
+	if (localaddr) {
+		s->localaddr = talloc_reference(c, localaddr);
+		if (composite_nomem(s->localaddr, c)) return c;
+	}
 	s->server    = talloc_reference(c, server);
 	if (composite_nomem(s->server, c)) return c;
 	s->target_hostname = talloc_reference(s, target_hostname);
@@ -337,7 +343,7 @@ static struct composite_context *dcerpc_pipe_open_socket_send(TALLOC_CTX *mem_ct
 
 	s->sock->path = talloc_reference(s->sock, full_path);
 
-	conn_req = socket_connect_send(s->socket_ctx, NULL, s->server, 0, 
+	conn_req = socket_connect_send(s->socket_ctx, s->localaddr, s->server, 0,
 				       c->event_ctx);
 	composite_continue(c, conn_req, continue_socket_connect, c);
 	return c;
@@ -357,6 +363,7 @@ struct pipe_tcp_state {
 	const char *target_hostname;
 	const char *address;
 	uint32_t port;
+	struct socket_address *localaddr;
 	struct socket_address *srvaddr;
 	struct resolve_context *resolve_ctx;
 	struct dcerpc_connection *conn;
@@ -385,7 +392,7 @@ static void continue_ip_resolve_name(struct composite_context *ctx)
 	if (composite_nomem(s->srvaddr, c)) return;
 
 	/* resolve_nbt_name gives only ipv4 ... - send socket open request */
-	sock_ipv4_req = dcerpc_pipe_open_socket_send(c, s->conn,
+	sock_ipv4_req = dcerpc_pipe_open_socket_send(c, s->conn, s->localaddr,
 						     s->srvaddr, s->target_hostname,
 						     NULL,
 						     NCACN_IP_TCP);
@@ -419,7 +426,7 @@ static void continue_ipv6_open_socket(struct composite_context *ctx)
 	if (composite_nomem(s->srvaddr, c)) return;
 
 	/* try IPv4 if IPv6 fails */
-	sock_ipv4_req = dcerpc_pipe_open_socket_send(c, s->conn, 
+	sock_ipv4_req = dcerpc_pipe_open_socket_send(c, s->conn, s->localaddr,
 						     s->srvaddr, s->target_hostname, 
 						     NCACN_IP_TCP);
 	composite_continue(c, sock_ipv4_req, continue_ipv4_open_socket, c);
@@ -452,12 +459,12 @@ static void continue_ipv4_open_socket(struct composite_context *ctx)
 	composite_done(c);
 }
 
-
 /*
   Send rpc pipe open request to given host:port using
   tcp/ip transport
 */
 struct composite_context* dcerpc_pipe_open_tcp_send(struct dcerpc_connection *conn,
+						    const char *localaddr,
 						    const char *server,
 						    const char *target_hostname,
 						    uint32_t port,
@@ -486,6 +493,12 @@ struct composite_context* dcerpc_pipe_open_tcp_send(struct dcerpc_connection *co
 	s->port            = port;
 	s->conn            = conn;
 	s->resolve_ctx     = resolve_ctx;
+	if (localaddr) {
+		s->localaddr = socket_address_from_strings(s, "ip", localaddr, 0);
+		/* if there is no localaddr, we pass NULL for
+		   s->localaddr, which is handled by the socket libraries as
+		   meaning no local binding address specified */
+	}
 
 	make_nbt_name_server(&name, server);
 	resolve_req = resolve_name_send(resolve_ctx, s, &name, c->event_ctx);
@@ -560,7 +573,7 @@ struct composite_context *dcerpc_pipe_open_unix_stream_send(struct dcerpc_connec
 	if (composite_nomem(s->srvaddr, c)) return c;
 
 	/* send socket open request */
-	sock_unix_req = dcerpc_pipe_open_socket_send(c, s->conn, 
+	sock_unix_req = dcerpc_pipe_open_socket_send(c, s->conn, NULL,
 						     s->srvaddr, NULL,
 						     s->path,
 						     NCALRPC);
@@ -631,7 +644,7 @@ struct composite_context* dcerpc_pipe_open_pipe_send(struct dcerpc_connection *c
 	if (composite_nomem(s->srvaddr, c)) return c;
 
 	/* send socket open request */
-	sock_np_req = dcerpc_pipe_open_socket_send(c, s->conn, s->srvaddr, NULL, s->path, NCALRPC);
+	sock_np_req = dcerpc_pipe_open_socket_send(c, s->conn, NULL, s->srvaddr, NULL, s->path, NCALRPC);
 	composite_continue(c, sock_np_req, continue_np_open_socket, c);
 	return c;
 }
diff --git a/source4/librpc/rpc/dcerpc_util.c b/source4/librpc/rpc/dcerpc_util.c
index ffe8506d21..d27b0f3f5b 100644
--- a/source4/librpc/rpc/dcerpc_util.c
+++ b/source4/librpc/rpc/dcerpc_util.c
@@ -285,6 +285,7 @@ struct composite_context *dcerpc_epm_map_binding_send(TALLOC_CTX *mem_ctx,
 	epmapper_binding->host			= talloc_reference(epmapper_binding, binding->host);
 	epmapper_binding->target_hostname       = epmapper_binding->host;
 	epmapper_binding->options		= NULL;
+	epmapper_binding->localaddress          = talloc_reference(epmapper_binding, binding->localaddress);
 	epmapper_binding->flags			= 0;
 	epmapper_binding->assoc_group_id	= 0;
 	epmapper_binding->endpoint		= NULL;
diff --git a/source4/librpc/tests/binding_string.c b/source4/librpc/tests/binding_string.c
index 6de94eb58b..dfb6d2967a 100644
--- a/source4/librpc/tests/binding_string.c
+++ b/source4/librpc/tests/binding_string.c
@@ -128,6 +128,12 @@ static bool test_parse_check_results(struct torture_context *tctx)
 	torture_assert_int_equal(tctx, b->object.if_version, 0, "object version");
 	torture_assert_ntstatus_ok(tctx, dcerpc_parse_binding(tctx, 
 		"308FB580-1EB2-11CA-923B-08002B1075A7@ncacn_ip_tcp:$SERVER", &b), "parse");
+	torture_assert_ntstatus_ok(tctx, dcerpc_parse_binding(tctx, "ncacn_ip_tcp:$SERVER[,sign,localaddress=192.168.1.1]", &b), "parse");
+	torture_assert(tctx, b->transport == NCACN_IP_TCP, "ncacn_ip_tcp expected");
+	torture_assert(tctx, b->flags == (DCERPC_SIGN | DCERPC_LOCALADDRESS), "sign flag");
+	torture_assert_str_equal(tctx, b->localaddress, "192.168.1.1", "localaddress");
+	torture_assert_str_equal(tctx, "ncacn_ip_tcp:$SERVER[,sign,localaddress=192.168.1.1]",
+				 dcerpc_binding_string(tctx, b), "back to string");
 
 	return true;
 }