IBM Support

Entering lockdown after startup by using sysfs might result in different behavior than entering lockdown normally at startup

Flashes (Alerts)


Abstract

Using sysfs to enter lockdown on Power10 systems can cause the system to behave differently than normal.

Content

Linux Releases Affected

Red Hat Enterprise Linux (RHEL) 8.5
Red Hat Enterprise Linux (RHEL) 8.6
Red Hat Enterprise Linux (RHEL) 9.0


IBM Systems Affected
All Power10 systems.

Symptoms

There are several ways that lockdown can be enabled:
  •  by using sysfs (e.g. `echo integrity > /sys/kernel/security/lockdown`).
  •  by using a kernel command line parameter ('lockdown=integrity').
  •  by booting under secure boot.
Entering lockdown after startup by using sysfs might result in different behavior than entering lockdown at startup. Processes that are run before entering lockdown are able to obtain resources or perform actions that would otherwise be blocked by the lockdown. When the lockdown is entered, those resources are not torn down and the actions cannot be undone.
To avoid this situation, you can avoid using sysfs to enable lockdown.

Workaround
You can use a different method (other than sysfs) to enable lockdown. 

Fix Outlook
There is no fix available for this issue.

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Document Information

Modified date:
06 June 2022

UID

ibm16558178