> Or even better, do not use setuid at all.
> For instance, imagine if ping, instead of being setuid, called into dbus to load a helper daemon, and that helper daemon did all the actions which need root (in this example, sending pings).
Actually a clean environment was the main point of what I suggested above - i.e. using a setuid loader which can clean the environment (not just the environment as in setenv of course) before it loads your privileged binary. My worry with using dbus for this is that it requires a sizeable piece of infrastructure to be present and running properly in order to start your binary, which is fine for desktop use, but may not be appropriate for all situations.