I'm seeing ioctl() set calls fail on an interface socket. You can see this easily by doing:

strace /sbin/ifconfig wlan0 up
...
ioctl(3, SIOCSIFFLAGS, {ifr_name="wlan0", ???}) = -1 EACCES (Permission denied)

The get commands work okay.

Is there some sort of security mechanism protecting such calls? If so, how do the other system configuration utilities pass parameters to the interface and down to the driver?