1 files changed, 348 insertions, 0 deletions
diff --git a/src/modules/module-portal.c b/src/modules/module-portal.c
new file mode 100644
index 0000000..ee5aa73
--- /dev/null
+++ b/src/modules/module-portal.c
@@ -0,0 +1,348 @@
+/* PipeWire
+ *
+ * Copyright © 2016 Wim Taymans <wim.taymans@gmail.com>
+ * Copyright © 2019 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "config.h"
+
+#include <dbus/dbus.h>
+
+#include <spa/utils/string.h>
+#include <spa/utils/result.h>
+#include <spa/support/dbus.h>
+
+#include "pipewire/context.h"
+#include "pipewire/impl-client.h"
+#include "pipewire/log.h"
+#include "pipewire/module.h"
+#include "pipewire/utils.h"
+
+/** \page page_module_portal PipeWire Module: Portal
+ *
+ * The `portal` module performs access control management for clients started
+ * inside an XDG portal.
+ *
+ * The module connects to the session DBus and subscribes to
+ * `NameOwnerChanged` signals for the `org.freedesktop.portal.Desktop` name.
+ * The PID of the DBus name owner is the portal.
+ *
+ * A client connection from the portal PID to PipeWire gets assigned a \ref
+ * PW_KEY_ACCESS of `"portal"` and set to permissions ALL - it is the
+ * responsibility of the portal to limit the permissions before passing the
+ * connection on to the client. See \ref page_access for details on
+ * permissions.
+ *
+ * Clients connecting from other PIDs are ignored by this module.
+ *
+ * ## Module Options
+ *
+ * There are no module-specific options.
+ *
+ * ## General options
+ *
+ * There are no general options for this module.
+ *
+ * ## Example configuration
+ *\code{.unparsed}
+ * context.modules = [
+ *  {   name = libpipewire-portal }
+ * ]
+ *\endcode
+ *
+ */
+
+#define NAME "portal"
+
+PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
+#define PW_LOG_TOPIC_DEFAULT mod_topic
+
+struct impl {
+	struct pw_context *context;
+	struct pw_properties *properties;
+
+	struct spa_dbus_connection *conn;
+	DBusConnection *bus;
+
+	struct spa_hook context_listener;
+	struct spa_hook module_listener;
+
+	DBusPendingCall *portal_pid_pending;
+	pid_t portal_pid;
+};
+
+static void
+context_check_access(void *data, struct pw_impl_client *client)
+{
+	struct impl *impl = data;
+	const struct pw_properties *props;
+	struct pw_permission permissions[1];
+	struct spa_dict_item items[1];
+	pid_t pid;
+
+	if (impl->portal_pid == 0)
+		return;
+
+	if ((props = pw_impl_client_get_properties(client)) == NULL)
+		return;
+
+	if (pw_properties_fetch_int32(props, PW_KEY_SEC_PID, &pid) < 0)
+		return;
+
+	if (pid != impl->portal_pid)
+		return;
+
+	items[0] = SPA_DICT_ITEM_INIT(PW_KEY_ACCESS, "portal");
+	pw_impl_client_update_properties(client, &SPA_DICT_INIT(items, 1));
+
+	pw_log_info("%p: portal managed client %p added", impl, client);
+
+	/* portal makes this connection and will change the permissions before
+	 * handing this connection to the client */
+	permissions[0] = PW_PERMISSION_INIT(PW_ID_ANY, PW_PERM_ALL);
+	pw_impl_client_update_permissions(client, 1, permissions);
+	return;
+}
+
+static const struct pw_context_events context_events = {
+	PW_VERSION_CONTEXT_EVENTS,
+	.check_access = context_check_access,
+};
+
+static void module_destroy(void *data)
+{
+	struct impl *impl = data;
+
+	spa_hook_remove(&impl->context_listener);
+	spa_hook_remove(&impl->module_listener);
+
+	if (impl->bus)
+		dbus_connection_unref(impl->bus);
+	spa_dbus_connection_destroy(impl->conn);
+
+	pw_properties_free(impl->properties);
+
+	free(impl);
+}
+
+static const struct pw_impl_module_events module_events = {
+	PW_VERSION_IMPL_MODULE_EVENTS,
+	.destroy = module_destroy,
+};
+
+static void on_portal_pid_received(DBusPendingCall *pending,
+				   void *user_data)
+{
+	struct impl *impl = user_data;
+	DBusMessage *m;
+	DBusError error;
+	uint32_t portal_pid = 0;
+
+	m = dbus_pending_call_steal_reply(pending);
+	dbus_pending_call_unref(pending);
+	impl->portal_pid_pending = NULL;
+
+	if (!m) {
+		pw_log_error("Failed to receive portal pid");
+		return;
+	}
+	if (dbus_message_is_error(m, DBUS_ERROR_NAME_HAS_NO_OWNER)) {
+		pw_log_info("Portal is not running");
+		return;
+	}
+	if (dbus_message_get_type(m) == DBUS_MESSAGE_TYPE_ERROR) {
+		const char *message = "unknown";
+		dbus_message_get_args(m, NULL, DBUS_TYPE_STRING, &message, DBUS_TYPE_INVALID);
+		pw_log_warn("Failed to receive portal pid: %s: %s",
+				dbus_message_get_error_name(m), message);
+		return;
+	}
+
+	dbus_error_init(&error);
+	dbus_message_get_args(m, &error, DBUS_TYPE_UINT32, &portal_pid,
+			      DBUS_TYPE_INVALID);
+	dbus_message_unref(m);
+
+	if (dbus_error_is_set(&error)) {
+		impl->portal_pid = 0;
+		pw_log_warn("Could not get portal pid: %s", error.message);
+		dbus_error_free(&error);
+	} else {
+		pw_log_info("Got portal pid %d", portal_pid);
+		impl->portal_pid = portal_pid;
+	}
+}
+
+static void update_portal_pid(struct impl *impl)
+{
+	DBusMessage *m;
+	const char *name;
+	DBusPendingCall *pending;
+
+	impl->portal_pid = 0;
+
+	m = dbus_message_new_method_call("org.freedesktop.DBus",
+					 "/org/freedesktop/DBus",
+					 "org.freedesktop.DBus",
+					 "GetConnectionUnixProcessID");
+
+	name = "org.freedesktop.portal.Desktop";
+	dbus_message_append_args(m,
+				 DBUS_TYPE_STRING, &name,
+				 DBUS_TYPE_INVALID);
+
+	dbus_connection_send_with_reply(impl->bus, m, &pending, -1);
+	dbus_pending_call_set_notify(pending, on_portal_pid_received, impl, NULL);
+	if (impl->portal_pid_pending != NULL) {
+		dbus_pending_call_cancel(impl->portal_pid_pending);
+		dbus_pending_call_unref(impl->portal_pid_pending);
+	}
+	impl->portal_pid_pending = pending;
+}
+
+static DBusHandlerResult name_owner_changed_handler(DBusConnection *connection,
+						    DBusMessage *message,
+						    void *user_data)
+{
+	struct impl *impl = user_data;
+	const char *name;
+	const char *old_owner;
+	const char *new_owner;
+
+	if (!dbus_message_is_signal(message, "org.freedesktop.DBus",
+				   "NameOwnerChanged"))
+		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+
+	if (!dbus_message_get_args(message, NULL,
+				   DBUS_TYPE_STRING, &name,
+				   DBUS_TYPE_STRING, &old_owner,
+				   DBUS_TYPE_STRING, &new_owner,
+				   DBUS_TYPE_INVALID)) {
+		pw_log_error("Failed to get OwnerChanged args");
+		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+	}
+
+	if (!spa_streq(name, "org.freedesktop.portal.Desktop"))
+		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+
+	if (spa_streq(new_owner, "")) {
+		impl->portal_pid = 0;
+		if (impl->portal_pid_pending != NULL) {
+			dbus_pending_call_cancel(impl->portal_pid_pending);
+			dbus_pending_call_unref(impl->portal_pid_pending);
+		}
+	}
+	else {
+		update_portal_pid(impl);
+	}
+
+	return DBUS_HANDLER_RESULT_HANDLED;
+}
+
+static int init_dbus_connection(struct impl *impl)
+{
+	DBusError error;
+
+	impl->bus = spa_dbus_connection_get(impl->conn);
+	if (impl->bus == NULL)
+		return -EIO;
+
+	/* XXX: we don't handle dbus reconnection yet, so ref the handle instead */
+	dbus_connection_ref(impl->bus);
+
+	dbus_error_init(&error);
+
+	dbus_bus_add_match(impl->bus,
+			   "type='signal',\
+			   sender='org.freedesktop.DBus',\
+			   interface='org.freedesktop.DBus',\
+			   member='NameOwnerChanged'",
+			   &error);
+	if (dbus_error_is_set(&error)) {
+		pw_log_error("Failed to add name owner changed listener: %s",
+			     error.message);
+		dbus_error_free(&error);
+		return -EIO;
+	}
+
+	dbus_connection_add_filter(impl->bus, name_owner_changed_handler,
+				   impl, NULL);
+
+	update_portal_pid(impl);
+
+	return 0;
+}
+
+SPA_EXPORT
+int pipewire__module_init(struct pw_impl_module *module, const char *args)
+{
+	struct pw_context *context = pw_impl_module_get_context(module);
+	struct impl *impl;
+	struct spa_dbus *dbus;
+	const struct spa_support *support;
+	uint32_t n_support;
+	int res;
+
+	PW_LOG_TOPIC_INIT(mod_topic);
+
+	support = pw_context_get_support(context, &n_support);
+
+	dbus = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DBus);
+        if (dbus == NULL)
+                return -ENOTSUP;
+
+	impl = calloc(1, sizeof(struct impl));
+	if (impl == NULL)
+		return -ENOMEM;
+
+	pw_log_debug("module %p: new", impl);
+
+	impl->context = context;
+	impl->properties = args ? pw_properties_new_string(args) : NULL;
+
+	impl->conn = spa_dbus_get_connection(dbus, SPA_DBUS_TYPE_SESSION);
+	if (impl->conn == NULL) {
+		res = -errno;
+		goto error;
+	}
+
+	if ((res = init_dbus_connection(impl)) < 0)
+		goto error;
+
+	pw_context_add_listener(context, &impl->context_listener, &context_events, impl);
+	pw_impl_module_add_listener(module, &impl->module_listener, &module_events, impl);
+
+	return 0;
+
+      error:
+	free(impl);
+	pw_log_error("Failed to connect to session bus: %s", spa_strerror(res));
+	return res;
+}