Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Configuring a System
Reconfiguring the Kernel (HP-UX 11i Version 2)
Chapter 3372
While Susan’s on vacation, her colleague, Fred, decides to use the
machine for billing software during the night. This software needs to
execute code on the stack (a security risk), so he enables that behavior
(which is prohibited by default). No reboot is needed to do so.
# kctune -d executable_stack
Tunable Value Expression Changes
Description
executable_stack 0 Default Immed
Enables execution of code on a stack (0 = no, 1 = yes, 2 = yes but warn)
# kctune -C "Nightly billing s/w needs execute-on-stack" executable_stack=1
* The automatic 'backup' configuration has been updated.
* The requested changes have been applied to the currently
running system.
Tunable Value Expression Changes
executable_stack (before) 0 Default Immed
(now) 1 1
The billing software also uses the kernel Random Number Generator
module. Fred checks and sees that it’s not in use, but since it’s loadable
he doesn’t need to reboot to use it.
# kcmodule -d rng
Module State Cause Notes
Description
rng unused loadable, unloadable
Strong Random Number Generator
He goes ahead and loads the module.
# kcmodule -C "Random Number Generator needed for nightly billing jobs" rng=best
* The automatic 'backup' configuration has been updated.
* The requested changes have been applied to the currently
running system.
Module State Cause Notes
rng (before) unused loadable, unloadable
(now) loaded best
Fred saves these new configuration settings under the name night (with
a descriptive title).
# kconfig -C "Settings for nightly billing jobs" -s night
* The current configuration has been saved to 'night'.
# kconfig -t night "Nightly billing jobs"
* The title of the configuration 'night' has been set to "Nightly
billing jobs".