CVE-2023-52677

What it actually does

The Linux kernel on RISC-V fails to validate whether code being patched resides in the exit section before calling vmalloc_to_page, causing a panic when the address is outside the vmalloc region.

Why it matters to the business

RISC-V Linux systems may experience unexpected kernel crashes during module unloading or exit-section patching operations, resulting in downtime and potential loss of availability for affected workloads.

How an attack unfolds

An attacker or legitimate workload triggers kernel code patching that targets an address in the exit section on a RISC-V system; the missing check causes the kernel to fall through to vmalloc_to_page on an invalid address and panic.

How to fix it

Update the Linux kernel to a version containing commit 938f70d14618ec72e10d6fcf8a546134136d7c13 or later stable releases that include the exit-section check for RISC-V patching.

How to confirm the fix worked

Verify the running kernel contains commit 938f70d14618ec72e10d6fcf8a546134136d7c13; confirm no vmalloc_to_page panic occurs during module unload or exit-section patching on RISC-V hardware.

Typical attack path

1. Identify or induce conditions that cause the kernel to patch code located in an exit section on RISC-V
2. Trigger the patching path without the exit-section guard
3. Kernel executes vmalloc_to_page on a non-vmalloc address
4. Kernel panics and system crashes

How to detect it

Search kernel logs and crash dumps for vmalloc_to_page calls or panic messages referencing addresses outside the vmalloc region during module exit or patching operations on RISC-V.

• vmalloc_to_page
• exit section
• riscv
• kernel panic

What your security team should do

• Apply the fixed kernel commit or equivalent stable release on all RISC-V systems as soon as possible
• Prioritize RISC-V production workloads for patching due to crash risk
• Monitor kernel logs for vmalloc_to_page or exit-section related panics until remediation is complete