CVE-2023-52675

What it actually does

Missing null pointer check after kasprintf() in update_events_in_group() allows NULL dereference, resulting in kernel panic and denial of service.

Why it matters to the business

Systems may experience unexpected crashes or restarts when running performance monitoring code under low-memory conditions, leading to service interruptions on affected Linux kernels.

How an attack unfolds

An attacker with local access triggers the imc-pmu event update path while the system is under memory pressure so that kasprintf() returns NULL; the subsequent dereference then crashes the kernel.

How to fix it

Update the Linux kernel to the commit 75fc599bcdcb1de093c9ced2e3cccc832f3787f3 or later stable release containing the added null pointer check in update_events_in_group().

How to confirm the fix worked

Confirm the presence of the null check after kasprintf() in the imc-pmu source and verify the running kernel includes commit 75fc599bcdcb1de093c9ced2e3cccc832f3787f3.

Typical attack path

1. Obtain local user access on a vulnerable powerpc Linux system
2. Induce memory exhaustion to force kasprintf() failure
3. Invoke performance counter group update operations via perf or similar interfaces
4. Trigger NULL dereference and resulting kernel panic

How to detect it

Review kernel logs for oops or panic messages referencing imc-pmu or update_events_in_group under memory pressure conditions.

What your security team should do

• Apply the referenced kernel commit or newer stable release immediately on all powerpc systems
• Prioritize patching production and high-availability environments first
• Monitor for kernel oops or panic events related to imc-pmu after deployment