NetworkManager/libnm-core/nm-vpn-editor-plugin.c

// SPDX-License-Identifier: LGPL-2.1+
/*
 * Copyright (C) 2008 Novell, Inc.
 * Copyright (C) 2008 - 2010 Red Hat, Inc.
 * Copyright (C) 2015 Red Hat, Inc.
 */

#include "nm-default.h"

#include "nm-vpn-editor-plugin.h"

#include <dlfcn.h>
#include <gmodule.h>

#include "nm-core-internal.h"

/*****************************************************************************/

static void nm_vpn_editor_plugin_default_init (NMVpnEditorPluginInterface *iface);

G_DEFINE_INTERFACE (NMVpnEditorPlugin, nm_vpn_editor_plugin, G_TYPE_OBJECT)

static void
nm_vpn_editor_plugin_default_init (NMVpnEditorPluginInterface *iface)
{
	/**
	 * NMVpnEditorPlugin:name:
	 *
	 * Short display name of the VPN plugin.
	 */
	g_object_interface_install_property (iface,
	    g_param_spec_string (NM_VPN_EDITOR_PLUGIN_NAME, "", "",
	                         NULL,
	                         G_PARAM_READABLE |
	                         G_PARAM_STATIC_STRINGS));

	/**
	 * NMVpnEditorPlugin:description:
	 *
	 * Longer description of the VPN plugin.
	 */
	g_object_interface_install_property (iface,
	    g_param_spec_string (NM_VPN_EDITOR_PLUGIN_DESCRIPTION, "", "",
	                         NULL,
	                         G_PARAM_READABLE |
	                         G_PARAM_STATIC_STRINGS));

	/**
	 * NMVpnEditorPlugin:service:
	 *
	 * D-Bus service name of the plugin's VPN service.
	 */
	g_object_interface_install_property (iface,
	    g_param_spec_string (NM_VPN_EDITOR_PLUGIN_SERVICE, "", "",
	                         NULL,
	                         G_PARAM_READABLE |
	                         G_PARAM_STATIC_STRINGS));
}

/*****************************************************************************/

typedef struct {
	NMVpnPluginInfo *plugin_info;
} NMVpnEditorPluginPrivate;

static void
_private_destroy (gpointer data)
{
	NMVpnEditorPluginPrivate *priv = data;

	if (priv->plugin_info)
		g_object_remove_weak_pointer ((GObject *) priv->plugin_info, (gpointer *) &priv->plugin_info);

	g_slice_free (NMVpnEditorPluginPrivate, priv);
}

static NMVpnEditorPluginPrivate *
_private_get (NMVpnEditorPlugin *plugin, gboolean create)
{
	static GQuark quark = 0;
	NMVpnEditorPluginPrivate *priv;

	nm_assert (NM_IS_VPN_EDITOR_PLUGIN (plugin));

	if (G_UNLIKELY (quark == 0))
		quark = g_quark_from_string ("nm-vpn-editor-plugin-private");

	priv = g_object_get_qdata ((GObject *) plugin, quark);
	if (G_LIKELY (priv))
		return priv;
	if (!create)
		return NULL;
	priv = g_slice_new0 (NMVpnEditorPluginPrivate);
	g_object_set_qdata_full ((GObject *) plugin, quark, priv, _private_destroy);
	return priv;
}

#define NM_VPN_EDITOR_PLUGIN_GET_PRIVATE(plugin)     _private_get (plugin, TRUE)
#define NM_VPN_EDITOR_PLUGIN_TRY_GET_PRIVATE(plugin) _private_get (plugin, FALSE)

/*****************************************************************************/

/**
 * nm_vpn_editor_plugin_get_plugin_info:
 * @plugin: the #NMVpnEditorPlugin instance
 *
 * Returns: (transfer none): if set, return the #NMVpnPluginInfo instance.
 *
 * Since: 1.4
 */
NMVpnPluginInfo *
nm_vpn_editor_plugin_get_plugin_info (NMVpnEditorPlugin *plugin)
{
	NMVpnEditorPluginPrivate *priv;

	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), NULL);

	priv = NM_VPN_EDITOR_PLUGIN_TRY_GET_PRIVATE (plugin);
	return priv ? priv->plugin_info : NULL;
}

/**
 * nm_vpn_editor_plugin_set_plugin_info:
 * @plugin: the #NMVpnEditorPlugin instance
 * @plugin_info: (allow-none): a #NMVpnPluginInfo instance or %NULL
 *
 * Set or clear the plugin-info instance.
 * This takes a weak reference on @plugin_info, to avoid circular
 * reference as the plugin-info might also reference the editor-plugin.
 *
 * Since: 1.4
 */
void
nm_vpn_editor_plugin_set_plugin_info (NMVpnEditorPlugin *plugin, NMVpnPluginInfo *plugin_info)
{
	NMVpnEditorPluginInterface *interface;
	NMVpnEditorPluginPrivate *priv;

	g_return_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin));

	if (!plugin_info) {
		priv = NM_VPN_EDITOR_PLUGIN_TRY_GET_PRIVATE (plugin);
		if (!priv)
			return;
	} else {
		g_return_if_fail (NM_IS_VPN_PLUGIN_INFO (plugin_info));
		priv = NM_VPN_EDITOR_PLUGIN_GET_PRIVATE (plugin);
	}

	if (priv->plugin_info == plugin_info)
		return;
	if (priv->plugin_info)
		g_object_remove_weak_pointer ((GObject *) priv->plugin_info, (gpointer *) &priv->plugin_info);
	priv->plugin_info = plugin_info;
	if (priv->plugin_info)
		g_object_add_weak_pointer ((GObject *) priv->plugin_info, (gpointer *) &priv->plugin_info);

	if (plugin_info) {
		interface = NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin);
		if (interface->notify_plugin_info_set)
			interface->notify_plugin_info_set (plugin, plugin_info);
	}

}

/*****************************************************************************/

/**
 * nm_vpn_editor_plugin_get_vt:
 * @plugin: the #NMVpnEditorPlugin
 * @vt: (out): buffer to be filled with the VT table of the plugin
 * @vt_size: the size of the buffer. Can be 0 to only query the
 *   size of plugin's VT.
 *
 * Returns an opaque VT function table for the plugin to extend
 * functionality. The actual meaning of NMVpnEditorPluginVT is not
 * defined in public API of libnm, instead it must be agreed by
 * both the plugin and the caller. See the header-only file
 * 'nm-vpn-editor-plugin-call.h' which defines the meaning.
 *
 * Returns: the actual size of the @plugin's virtual function table.
 *
 * Since: 1.4
 **/
gsize
nm_vpn_editor_plugin_get_vt (NMVpnEditorPlugin *plugin,
                             NMVpnEditorPluginVT *vt,
                             gsize vt_size)
{
	const NMVpnEditorPluginVT *p_vt = NULL;
	gsize p_vt_size = 0;
	NMVpnEditorPluginInterface *interface;

	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), 0);

	if (vt_size) {
		g_return_val_if_fail (vt, 0);
		memset (vt, 0, vt_size);
	}

	interface = NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin);
	if (interface->get_vt) {
		p_vt = interface->get_vt (plugin, &p_vt_size);
		if (!p_vt)
			p_vt_size = 0;
		g_return_val_if_fail (p_vt_size, 0);
		memcpy (vt, p_vt, MIN (vt_size, p_vt_size));
	}

	return p_vt_size;
}

/*****************************************************************************/

static NMVpnEditorPlugin *
_nm_vpn_editor_plugin_load (const char *plugin_name,
                            gboolean do_file_checks,
                            const char *check_service,
                            int check_owner,
                            NMUtilsCheckFilePredicate check_file,
                            gpointer user_data,
                            GError **error)
{
	void *dl_module = NULL;
	gboolean loaded_before;
	NMVpnEditorPluginFactory factory = NULL;
	gs_unref_object NMVpnEditorPlugin *editor_plugin = NULL;
	gs_free char *plugin_filename_free = NULL;
	const char *plugin_filename;
	gs_free_error GError *factory_error = NULL;
	gs_free char *plug_name = NULL;
	gs_free char *plug_service = NULL;

	g_return_val_if_fail (plugin_name && *plugin_name, NULL);

	/* if @do_file_checks is FALSE, we pass plugin_name directly to
	 * g_module_open().
	 *
	 * Otherwise, we allow for library names without path component.
	 * In which case, we prepend the plugin directory and form an
	 * absolute path. In that case, we perform checks on the file.
	 *
	 * One exception is that we don't allow for the "la" suffix. The
	 * reason is that g_module_open() interprets files with this extension
	 * special and we don't want that. */
	plugin_filename = plugin_name;
	if (do_file_checks) {
		if (   !strchr (plugin_name, '/')
		    && !g_str_has_suffix (plugin_name, ".la")) {
			plugin_filename_free = g_module_build_path (NMVPNDIR, plugin_name);
			plugin_filename = plugin_filename_free;
		}
	}

	dl_module = dlopen (plugin_filename, RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
	if (   !dl_module
	    && do_file_checks) {
		/* If the module is already loaded, we skip the file checks.
		 *
		 * _nm_utils_check_module_file() fails with ENOENT if the plugin file
		 * does not exist. That is relevant, because nm-applet checks for that. */
		if (!_nm_utils_check_module_file (plugin_filename,
		                                  check_owner,
		                                  check_file,
		                                  user_data,
		                                  error))
			return NULL;
	}

	if (dl_module) {
		loaded_before = TRUE;
	} else {
		loaded_before = FALSE;
		dl_module = dlopen (plugin_filename, RTLD_LAZY | RTLD_LOCAL);
	}

	if (!dl_module) {
		g_set_error (error,
		             NM_VPN_PLUGIN_ERROR,
		             NM_VPN_PLUGIN_ERROR_FAILED,
		             _("cannot load plugin \"%s\": %s"),
		             plugin_name,
		             dlerror () ?: "unknown reason");
		return NULL;
	}

	factory = dlsym (dl_module, "nm_vpn_editor_plugin_factory");
	if (!factory) {
		g_set_error (error,
		             NM_VPN_PLUGIN_ERROR,
		             NM_VPN_PLUGIN_ERROR_FAILED,
		             _("failed to load nm_vpn_editor_plugin_factory() from %s (%s)"),
		             plugin_name, dlerror ());
		dlclose (dl_module);
		return NULL;
	}

	editor_plugin = factory (&factory_error);

	if (loaded_before) {
		/* we want to leak the library, because the factory will register glib
		 * types, which cannot be unregistered.
		 *
		 * However, if the library was already loaded before, we want to return
		 * our part of the reference count. */
		dlclose (dl_module);
	}

	if (!editor_plugin) {
		if (factory_error) {
			g_propagate_error (error, factory_error);
			factory_error = NULL;
		} else {
			g_set_error (error,
			             NM_VPN_PLUGIN_ERROR,
			             NM_VPN_PLUGIN_ERROR_FAILED,
			             _("unknown error initializing plugin %s"), plugin_name);
		}
		return NULL;
	}

	g_return_val_if_fail (G_IS_OBJECT (editor_plugin), NULL);

	/* Validate plugin properties */
	g_object_get (G_OBJECT (editor_plugin),
	              NM_VPN_EDITOR_PLUGIN_NAME, &plug_name,
	              NM_VPN_EDITOR_PLUGIN_SERVICE, &plug_service,
	              NULL);

	if (!plug_name || !*plug_name) {
		g_set_error (error,
		             NM_VPN_PLUGIN_ERROR,
		             NM_VPN_PLUGIN_ERROR_FAILED,
		             _("cannot load VPN plugin in '%s': missing plugin name"),
		             plugin_name);
		return NULL;
	}
	if (   check_service
	    && g_strcmp0 (plug_service, check_service) != 0) {
		g_set_error (error,
		             NM_VPN_PLUGIN_ERROR,
		             NM_VPN_PLUGIN_ERROR_FAILED,
		             _("cannot load VPN plugin in '%s': invalid service name"),
		             plugin_name);
		return NULL;
	}

	return g_steal_pointer (&editor_plugin);
}

/**
 * nm_vpn_editor_plugin_load_from_file:
 * @plugin_name: The path or name of the shared library to load.
 *  The path must either be an absolute filename to an existing file.
 *  Alternatively, it can be the name (without path) of a library in the
 *  plugin directory of NetworkManager.
 * @check_service: if not-null, check that the loaded plugin advertises
 *  the given service.
 * @check_owner: if non-negative, check whether the file is owned
 *  by UID @check_owner or by root. In this case also check that
 *  the file is not writable by anybody else.
 * @check_file: (scope call): optional callback to validate the file prior to
 *   loading the shared library.
 * @user_data: user data for @check_file
 * @error: on failure the error reason.
 *
 * Load the shared library @plugin_name and create a new
 * #NMVpnEditorPlugin instance via the #NMVpnEditorPluginFactory
 * function.
 *
 * If @plugin_name is not an absolute path name, it assumes the file
 * is in the plugin directory of NetworkManager. In any case, the call
 * will do certain checks on the file before passing it to dlopen.
 * A consequence for that is, that you cannot omit the ".so" suffix
 * as you could for nm_vpn_editor_plugin_load().
 *
 * Returns: (transfer full): a new plugin instance or %NULL on error.
 *
 * Since: 1.2
 */
NMVpnEditorPlugin *
nm_vpn_editor_plugin_load_from_file  (const char *plugin_name,
                                      const char *check_service,
                                      int check_owner,
                                      NMUtilsCheckFilePredicate check_file,
                                      gpointer user_data,
                                      GError **error)
{
	return _nm_vpn_editor_plugin_load (plugin_name,
	                                   TRUE,
	                                   check_service,
	                                   check_owner,
	                                   check_file,
	                                   user_data,
	                                   error);
}

/**
 * nm_vpn_editor_plugin_load:
 * @plugin_name: The name of the shared library to load.
 *  This path will be directly passed to dlopen() without
 *  further checks.
 * @check_service: if not-null, check that the loaded plugin advertises
 *  the given service.
 * @error: on failure the error reason.
 *
 * Load the shared library @plugin_name and create a new
 * #NMVpnEditorPlugin instance via the #NMVpnEditorPluginFactory
 * function.
 *
 * This is similar to nm_vpn_editor_plugin_load_from_file(), but
 * it does no validation of the plugin name, instead passes it directly
 * to dlopen(). If you have the full path to a plugin file,
 * nm_vpn_editor_plugin_load_from_file() is preferred.
 *
 * Returns: (transfer full): a new plugin instance or %NULL on error.
 *
 * Since: 1.4
 */
NMVpnEditorPlugin *
nm_vpn_editor_plugin_load (const char *plugin_name,
                           const char *check_service,
                           GError **error)
{
	return _nm_vpn_editor_plugin_load (plugin_name,
	                                   FALSE,
	                                   check_service,
	                                   -1,
	                                   NULL,
	                                   NULL,
	                                   error);
}

/*****************************************************************************/

/**
 * nm_vpn_editor_plugin_get_editor:
 * @plugin: the #NMVpnEditorPlugin
 * @connection: the #NMConnection to be edited
 * @error: on return, an error or %NULL
 *
 * Returns: (transfer full): a new #NMVpnEditor or %NULL on error
 */
NMVpnEditor *
nm_vpn_editor_plugin_get_editor (NMVpnEditorPlugin *plugin,
                                 NMConnection *connection,
                                 GError **error)
{
	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), NULL);

	return NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->get_editor (plugin, connection, error);
}

NMVpnEditorPluginCapability
nm_vpn_editor_plugin_get_capabilities (NMVpnEditorPlugin *plugin)
{
	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), 0);

	return NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->get_capabilities (plugin);
}

/**
 * nm_vpn_editor_plugin_import:
 * @plugin: the #NMVpnEditorPlugin
 * @path: full path to the file to attempt to read into a new #NMConnection
 * @error: on return, an error or %NULL
 *
 * Returns: (transfer full): a new #NMConnection imported from @path, or %NULL
 * on error or if the file at @path was not recognized by this plugin
 */
NMConnection *
nm_vpn_editor_plugin_import (NMVpnEditorPlugin *plugin,
                             const char *path,
                             GError **error)
{
	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), NULL);

	if (nm_vpn_editor_plugin_get_capabilities (plugin) & NM_VPN_EDITOR_PLUGIN_CAPABILITY_IMPORT) {
		g_return_val_if_fail (NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->import_from_file != NULL, NULL);
		return NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->import_from_file (plugin, path, error);
	}

	g_set_error (error,
	             NM_VPN_PLUGIN_ERROR,
	             NM_VPN_PLUGIN_ERROR_FAILED,
	             _("the plugin does not support import capability"));
	return NULL;
}

gboolean
nm_vpn_editor_plugin_export (NMVpnEditorPlugin *plugin,
                             const char *path,
                             NMConnection *connection,
                             GError **error)
{
	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), FALSE);

	if (nm_vpn_editor_plugin_get_capabilities (plugin) & NM_VPN_EDITOR_PLUGIN_CAPABILITY_EXPORT) {
		g_return_val_if_fail (NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->export_to_file != NULL, FALSE);
		return NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->export_to_file (plugin, path, connection, error);
	}

	g_set_error (error,
	             NM_VPN_PLUGIN_ERROR,
	             NM_VPN_PLUGIN_ERROR_FAILED,
	             _("the plugin does not support export capability"));
	return FALSE;
}

char *
nm_vpn_editor_plugin_get_suggested_filename (NMVpnEditorPlugin *plugin,
                                             NMConnection *connection)
{
	g_return_val_if_fail (NM_IS_VPN_EDITOR_PLUGIN (plugin), NULL);

	if (NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->get_suggested_filename)
		return NM_VPN_EDITOR_PLUGIN_GET_INTERFACE (plugin)->get_suggested_filename (plugin, connection);
	return NULL;
}