gdbusobjectmanagerserver: Disallow child objects at /

Previously, the code validated that child objects have a path with the
object manager strictly as a prefix. That doesn’t work in the case where
the object manager’s path is `/`. This case is not recommended, but is
supported.

If the object manager’s path is `/`, validate that child objects’ paths
are not equal to it. If they are equal to it, warn the user rather than
emitting a critical warning, since we can’t expect any users who’ve not
been compliant with the spec to instantly rework their D-Bus APIs.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

Fixes: #2500
This commit is contained in:
Philip Withnall 2021-10-01 10:43:14 +01:00
parent 1c37f08004
commit f0e0754f62

View File

@ -457,10 +457,31 @@ registration_data_free (RegistrationData *data)
g_free (data);
}
/* Validate whether an object path is valid as a child of the manager. According
* to the specification:
* https://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-objectmanager
* this means that:
* > All returned object paths are children of the object path implementing this
* > interface, i.e. their object paths start with the ObjectManager's object
* > path plus '/'
*
* For example, if the manager is at `/org/gnome/Example`, children will be
* `/org/gnome/Example/(.+)`.
*
* It is permissible (but not encouraged) for the manager to be at `/`. If so,
* children will be `/(.+)`.
*/
static gboolean
is_valid_child_object_path (GDBusObjectManagerServer *manager,
const gchar *child_object_path)
{
/* Historically GDBus accepted @child_object_paths at `/` if the @manager
* itself is also at `/". This is not spec-compliant, but making GDBus enforce
* the spec more strictly would be an incompatible change.
*
* See https://gitlab.gnome.org/GNOME/glib/-/issues/2500 */
g_warn_if_fail (!g_str_equal (child_object_path, manager->priv->object_path_ending_in_slash));
return g_str_has_prefix (child_object_path, manager->priv->object_path_ending_in_slash);
}