/* GDBus - GLib D-Bus Library

 *

 * Copyright (C) 2008-2010 Red Hat, Inc.

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General

 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.

 *

 * Author: David Zeuthen <davidz@redhat.com>

 */

#include "config.h"

#include "gdbusauthobserver.h"

#include "gcredentials.h"

#include "gioenumtypes.h"

#include "giostream.h"

#include "gdbusprivate.h"

#include "glibintl.h"

#include "gmarshal-internal.h"

/**

 * GDBusAuthObserver:

 *

 * `GDBusAuthObserver` provides a mechanism for participating

 * in how a [class@Gio.DBusServer] (or a [class@Gio.DBusConnection])

 * authenticates remote peers.

 *

 * Simply instantiate a `GDBusAuthObserver` and connect to the

 * signals you are interested in. Note that new signals may be added

 * in the future.

 *

 * ## Controlling Authentication Mechanisms

 *

 * By default, a `GDBusServer` or server-side `GDBusConnection` will allow

 * any authentication mechanism to be used. If you only want to allow D-Bus

 * connections with the `EXTERNAL` mechanism, which makes use of credentials

 * passing and is the recommended mechanism for modern Unix platforms such

 * as Linux and the BSD family, you would use a signal handler like this:

 *

 * ```c

 * static gboolean

 * on_allow_mechanism (GDBusAuthObserver *observer,

 *                     const gchar       *mechanism,

 *                     gpointer           user_data)

 * {

 *   if (g_strcmp0 (mechanism, "EXTERNAL") == 0)

 *     {

 *       return TRUE;

 *     }

 *

 *   return FALSE;

 * }

 * ```

 *

 * ## Controlling Authorization

 *

 * By default, a `GDBusServer` or server-side `GDBusConnection` will accept

 * connections from any successfully authenticated user (but not from

 * anonymous connections using the `ANONYMOUS` mechanism). If you only

 * want to allow D-Bus connections from processes owned by the same uid

 * as the server, since GLib 2.68, you should use the

 * `G_DBUS_SERVER_FLAGS_AUTHENTICATION_REQUIRE_SAME_USER` flag. It’s equivalent

 * to the following signal handler:

 *

 * ```c

 * static gboolean

 * on_authorize_authenticated_peer (GDBusAuthObserver *observer,

 *                                  GIOStream         *stream,

 *                                  GCredentials      *credentials,

 *                                  gpointer           user_data)

 * {

 *   gboolean authorized;

 *

 *   authorized = FALSE;

 *   if (credentials != NULL)

 *     {

 *       GCredentials *own_credentials;

 *       own_credentials = g_credentials_new ();

 *       if (g_credentials_is_same_user (credentials, own_credentials, NULL))

 *         authorized = TRUE;

 *       g_object_unref (own_credentials);

 *     }

 *

 *   return authorized;

 * }

 * ```

 *

 * Since: 2.26

 */

typedef struct _GDBusAuthObserverClass GDBusAuthObserverClass;

/**

 * GDBusAuthObserverClass:

 * @authorize_authenticated_peer: Signal class handler for the #GDBusAuthObserver::authorize-authenticated-peer signal.

 *

 * Class structure for #GDBusAuthObserverClass.

 *

 * Since: 2.26

 */

struct _GDBusAuthObserverClass

{

  /*< private >*/

  GObjectClass parent_class;

  /*< public >*/

  /* Signals */

  gboolean (*authorize_authenticated_peer) (GDBusAuthObserver  *observer,

                                            GIOStream          *stream,

                                            GCredentials       *credentials);

  gboolean (*allow_mechanism) (GDBusAuthObserver  *observer,

                               const gchar        *mechanism);

};

struct _GDBusAuthObserver

{

  GObject parent_instance;

};

enum

{

  AUTHORIZE_AUTHENTICATED_PEER_SIGNAL,

  ALLOW_MECHANISM_SIGNAL,

  LAST_SIGNAL,

};

static guint signals[LAST_SIGNAL] = { 0 };

G_DEFINE_TYPE (GDBusAuthObserver, g_dbus_auth_observer, G_TYPE_OBJECT)

/* ---------------------------------------------------------------------------------------------------- */

static void

g_dbus_auth_observer_finalize (GObject *object)

{

  G_OBJECT_CLASS (g_dbus_auth_observer_parent_class)->finalize (object);

}

static gboolean

g_dbus_auth_observer_authorize_authenticated_peer_real (GDBusAuthObserver  *observer,

                                                        GIOStream          *stream,

                                                        GCredentials       *credentials)

{

  return TRUE;

}

static gboolean

g_dbus_auth_observer_allow_mechanism_real (GDBusAuthObserver  *observer,

                                           const gchar        *mechanism)

{

  return TRUE;

}

static void

g_dbus_auth_observer_class_init (GDBusAuthObserverClass *klass)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->finalize = g_dbus_auth_observer_finalize;

  klass->authorize_authenticated_peer = g_dbus_auth_observer_authorize_authenticated_peer_real;

  klass->allow_mechanism = g_dbus_auth_observer_allow_mechanism_real;

  /**

   * GDBusAuthObserver::authorize-authenticated-peer:

   * @observer: The #GDBusAuthObserver emitting the signal.

   * @stream: A #GIOStream for the #GDBusConnection.

   * @credentials: (nullable): Credentials received from the peer or %NULL.

   *

   * Emitted to check if a peer that is successfully authenticated

   * is authorized.

   *

   * Returns: %TRUE if the peer is authorized, %FALSE if not.

   *

   * Since: 2.26

   */

  signals[AUTHORIZE_AUTHENTICATED_PEER_SIGNAL] =

    g_signal_new (I_("authorize-authenticated-peer"),

                  G_TYPE_DBUS_AUTH_OBSERVER,

                  G_SIGNAL_RUN_LAST,

                  G_STRUCT_OFFSET (GDBusAuthObserverClass, authorize_authenticated_peer),

                  _g_signal_accumulator_false_handled,

                  NULL, /* accu_data */

                  _g_cclosure_marshal_BOOLEAN__OBJECT_OBJECT,

                  G_TYPE_BOOLEAN,

                  2,

                  G_TYPE_IO_STREAM,

                  G_TYPE_CREDENTIALS);

  g_signal_set_va_marshaller (signals[AUTHORIZE_AUTHENTICATED_PEER_SIGNAL],

                              G_TYPE_FROM_CLASS (klass),

                              _g_cclosure_marshal_BOOLEAN__OBJECT_OBJECTv);

  /**

   * GDBusAuthObserver::allow-mechanism:

   * @observer: The #GDBusAuthObserver emitting the signal.

   * @mechanism: The name of the mechanism, e.g. `DBUS_COOKIE_SHA1`.

   *

   * Emitted to check if @mechanism is allowed to be used.

   *

   * Returns: %TRUE if @mechanism can be used to authenticate the other peer, %FALSE if not.

   *

   * Since: 2.34

   */

  signals[ALLOW_MECHANISM_SIGNAL] =

    g_signal_new (I_("allow-mechanism"),

                  G_TYPE_DBUS_AUTH_OBSERVER,

                  G_SIGNAL_RUN_LAST,

                  G_STRUCT_OFFSET (GDBusAuthObserverClass, allow_mechanism),

                  _g_signal_accumulator_false_handled,

                  NULL, /* accu_data */

                  _g_cclosure_marshal_BOOLEAN__STRING,

                  G_TYPE_BOOLEAN,

                  1,

                  G_TYPE_STRING);

  g_signal_set_va_marshaller (signals[ALLOW_MECHANISM_SIGNAL],

                              G_TYPE_FROM_CLASS (klass),

                              _g_cclosure_marshal_BOOLEAN__STRINGv);

}

static void

g_dbus_auth_observer_init (GDBusAuthObserver *observer)

{

}

/**

 * g_dbus_auth_observer_new:

 *

 * Creates a new #GDBusAuthObserver object.

 *

 * Returns: A #GDBusAuthObserver. Free with g_object_unref().

 *

 * Since: 2.26

 */

GDBusAuthObserver *

g_dbus_auth_observer_new (void)

{

  return g_object_new (G_TYPE_DBUS_AUTH_OBSERVER, NULL);

}

/* ---------------------------------------------------------------------------------------------------- */

/**

 * g_dbus_auth_observer_authorize_authenticated_peer:

 * @observer: A #GDBusAuthObserver.

 * @stream: A #GIOStream for the #GDBusConnection.

 * @credentials: (nullable): Credentials received from the peer or %NULL.

 *

 * Emits the #GDBusAuthObserver::authorize-authenticated-peer signal on @observer.

 *

 * Returns: %TRUE if the peer is authorized, %FALSE if not.

 *

 * Since: 2.26

 */

gboolean

g_dbus_auth_observer_authorize_authenticated_peer (GDBusAuthObserver  *observer,

                                                   GIOStream          *stream,

                                                   GCredentials       *credentials)

{

  gboolean denied;

  denied = FALSE;

  g_signal_emit (observer,

                 signals[AUTHORIZE_AUTHENTICATED_PEER_SIGNAL],

                 0,

                 stream,

                 credentials,

                 &denied);

  return denied;

}

/**

 * g_dbus_auth_observer_allow_mechanism:

 * @observer: A #GDBusAuthObserver.

 * @mechanism: The name of the mechanism, e.g. `DBUS_COOKIE_SHA1`.

 *

 * Emits the #GDBusAuthObserver::allow-mechanism signal on @observer.

 *

 * Returns: %TRUE if @mechanism can be used to authenticate the other peer, %FALSE if not.

 *

 * Since: 2.34

 */

gboolean

g_dbus_auth_observer_allow_mechanism (GDBusAuthObserver  *observer,

                                      const gchar        *mechanism)

{

  gboolean ret;

  ret = FALSE;

  g_signal_emit (observer,

                 signals[ALLOW_MECHANISM_SIGNAL],

                 0,

                 mechanism,

                 &ret);

  return ret;

}