CVE-2024-27408

What it actually does

Race condition in dw-edma eDMA remote setup allows doorbell register toggle before linked list write completes due to separate memory locations for elements and controller registers.

Why it matters to the business

Potential DMA transfer failures or data inconsistencies on affected Linux systems could disrupt storage, networking, or peripheral operations in servers and embedded devices, though impact is limited by low exploitability and narrow driver scope.

How an attack unfolds

An attacker with local access triggers DMA operations in remote eDMA configuration, racing the doorbell write against incomplete linked list memory updates to induce transfer errors or undefined behavior.

How to fix it

Update the Linux kernel to include commit d24fe6d5a1cfdddb7a9ef56736ec501c4d0a5fd3 which adds a sync readl before starting DMA transfers in remote eDMA setup.

How to confirm the fix worked

Verify the presence of the sync readl barrier in dw-edma driver source or confirm kernel build includes the referenced commit; test DMA transfers in remote configuration for correct ordering.

Typical attack path

1. Obtain local code execution or driver access on target Linux system
2. Configure or trigger remote eDMA setup involving linked list elements
3. Time doorbell register toggle before full memory write of list completes
4. Observe resulting DMA errors, corruption, or denial of service

How to detect it

Review kernel logs for DMA engine errors or transfer failures around dw-edma remote setups; inspect for repeated doorbell or linked list anomalies in driver traces.

What your security team should do

• Apply the kernel patch containing d24fe6d5a1cfdddb7a9ef56736ec501c4d0a5fd3 to all affected stable branches
• Prioritize updates on systems using dw-edma remote DMA configurations such as certain embedded or storage platforms
• Monitor for any downstream dependent packages or distributions shipping vulnerable kernels