Vulnerability Discussion

Kernel page-table isolation is a kernel feature that mitigates the Meltdown security vulnerability and hardens the kernel against attempts to bypass kernel address space layout randomization (KASLR).

Satisfies: SRG-OS-000433-GPOS-00193, SRG-OS-000095-GPOS-00049

Check

Verify RHEL 9 enables kernel page-table isolation with the following command:

$ sudo grubby --info=ALL | grep args | grep -v 'pti=on'

If any output is returned, this is a finding.

Check that kernel page-table isolation is enabled by default to persist in kernel updates:

$ grep pti /etc/default/grub

GRUB_CMDLINE_LINUX="pti=on"

If "pti" is not set to "on", is missing or commented out, this is a finding.

Fix

Configure RHEL 9 to enable kernel page-table isolation with the following command:

$ sudo grubby --update-kernel=ALL --args="pti=on"

Add or modify the following line in "/etc/default/grub" to ensure the configuration survives kernel updates:

GRUB_CMDLINE_LINUX="pti=on"