CVE-2024-47663

What it actually does

Missing input validation in ad9834_write_frequency() allows clk_get_rate() returning 0 or fout==0 to reach a division in ad9834_calc_freqreg(), causing a kernel division-by-zero fault.

Why it matters to the business

Systems using the ad9834 frequency synthesizer driver can experience sudden kernel crashes or hangs when an untrusted frequency value is written, leading to loss of device control and requiring reboot.

How an attack unfolds

An attacker with write access to the device's frequency sysfs attribute supplies a crafted value (including zero) that bypasses the existing fout check; when clk_freq is also zero the subsequent division triggers a kernel panic. Threat actors in 2024 espionage and financially motivated campaigns have targeted similar Linux kernel input-validation flaws for initial access or denial of service.

How to fix it

Apply the upstream fix in commit 5edc3a45ef428501000a7b23d0e1777a548907f6 or later; rebuild and deploy the patched kernel to all affected systems. Disable the ad9834 staging driver if the hardware is not required.

How to confirm the fix worked

Verify the running kernel contains commit 5edc3a45ef428501000a7b23d0e1777a548907f6 or confirm the patched parameter checks are present in ad9834_write_frequency(); test by writing zero and boundary values to the frequency attribute and ensuring no panic occurs.

Typical attack path

1. Identify a Linux system exposing the ad9834 device through sysfs or character device.
2. Write an arbitrary frequency string (including 0) to the frequency attribute.
3. Trigger the ad9834_write() path that calls ad9834_write_frequency() without proper bounds.
4. Cause division by zero inside ad9834_calc_freqreg() and crash the kernel.

How to detect it

Search kernel logs and dmesg for oops or panic messages containing ad9834_calc_freqreg or division by zero; inspect audit logs for writes to ad9834 frequency sysfs files by unexpected processes.

What your security team should do

• Prioritize patching all Linux kernels that include the ad9834 staging driver within the next maintenance window.
• Review device exposure: restrict write access to frequency attributes to trusted processes only.
• Monitor kernel logs for division-by-zero oops entries referencing ad9834_calc_freqreg.
• Consider blacklisting the staging driver module if the hardware is unused.