CVE-2024-47664

What it actually does

Unvalidated max_speed_hz value of 0 from firmware leads to division by zero in hisi_calc_effective_speed() within the hisi-kunpeng SPI driver.

Why it matters to the business

Potential system crash or denial of service on affected Linux systems using this hardware, disrupting operations until patched.

How an attack unfolds

An attacker influences firmware or provides a malicious max_frequency value of 0; when the driver initializes SPI and calls hisi_calc_effective_speed the kernel performs a divide-by-zero resulting in a crash. Threat actors in 2024 Zero-Day Exploitation Campaigns and Linux kernel resource vulnerabilities have targeted similar kernel flaws.

How to fix it

Update the Linux kernel to the fixed commit 16ccaf581da4fcf1e4d66086cf37263f9a656d43 or later. If the vault package is present update to version 1.5.4.

How to confirm the fix worked

Confirm the driver source contains the added check rejecting max_speed_hz == 0 and returning an error before any division; verify running kernel version includes the commit.

Typical attack path

1. Locate systems running vulnerable hisi-kunpeng SPI driver
2. Supply firmware or device data setting max_speed_hz to 0
3. Trigger SPI device probe or speed configuration
4. Induce division by zero and kernel failure

How to detect it

Search kernel logs and crash dumps for division-by-zero faults or oops mentioning hisi_calc_effective_speed or hisi-kunpeng SPI initialization.

• hisi_calc_effective_speed
• max_speed_hz
• division by zero in hisi-kunpeng

What your security team should do

• Apply the kernel update containing commit 16ccaf581da4fcf1e4d66086cf37263f9a656d43 with highest priority
• Reboot affected systems after patching
• Audit firmware sources for SPI devices
• Monitor kernel logs for related oops entries