CVE-2022-49964

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

arm64: cacheinfo: Fix incorrect assignment of signed error value to unsigned fw_level

Though acpi_find_last_cache_level() always returned signed value and the

document states it will return any errors caused by lack of a PPTT table,

it never returned negative values before.

Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage")

however changed it by returning -ENOENT if no PPTT was found. The value

returned from acpi_find_last_cache_level() is then assigned to unsigned

fw_level.

It will result in the number of cache leaves calculated incorrectly as

a huge value which will then cause the following warning from __alloc_pages

as the order would be great than MAX_ORDER because of incorrect and huge

cache leaves value.

| WARNING: CPU: 0 PID: 1 at mm/page_alloc.c:5407 __alloc_pages+0x74/0x314

| Modules linked in:

| CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-10393-g7c2a8d3ac4c0 #7

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References