errata 005 for OpenBSD 4.2: local users can provoke a kernel panic
Improper checks in an ioctl can lead to a kernel panic.
recently added calls to rtlabel_id2name() for "ifconfig rtlabel"
did not properly check the return value before using it.
rtlabel_id2name can return NULL if there is no label assigned
or the ID is invalid.
local users can cause a kernel panic by using the SIOCGIFRTLABEL
ioctl on interfaces with no route label assigned.
ifconfig does not use that ioctl.
A fix has been committed to OpenBSD-current and the OpenBSD 4.2-stable
A patch for OpenBSD 4.2 will appear at the URL below shortly.