CVE-2024-42248

What it actually does

Missing NULL check on pdev->dev.of_node in the ma35d1 serial driver allows NULL pointer dereference during initialization when the serial device tree node is absent, resulting in kernel panic.

Why it matters to the business

Local users on affected systems can trigger denial of service through unexpected system crashes, disrupting operations on hardware using this serial driver without proper device tree setup.

How an attack unfolds

An attacker with local access ensures or triggers a scenario where the serial device tree node is absent, causing the driver to dereference a NULL pointer on initialization and crash the kernel.

How to fix it

Update Linux kernel to commit 23efa74cfe6eb923abb5b9bc51b2a04879013c67 or later; for AlmaLinux 8 update libtevent, libtevent-devel and python3-tevent to 0.11.0-0.el8.

How to confirm the fix worked

Confirm kernel source contains the added NULL check for of_node before returning error; verify updated package versions are installed and test driver probe with missing node.

Typical attack path

1. Obtain local user access on target system
2. Ensure absence of serial device tree node
3. Trigger ma35d1 driver initialization or probe
4. Induce kernel panic via NULL dereference

How to detect it

Inspect dmesg, syslog and kernel logs for oops or panic messages referencing ma35d1, of_node or serial driver initialization failures.

What your security team should do

• Apply kernel and package updates to fixed versions without delay
• Audit device tree configurations for serial nodes on affected hardware
• Restrict local access where possible until patched
• Monitor kernel logs for ma35d1 related panics