CVE-2022-48797

/// Technical description

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

mm: don't try to NUMA-migrate COW pages that have other uses

Oded Gabbay reports that enabling NUMA balancing causes corruption with

his Gaudi accelerator test load:

"All the details are in the bug, but the bottom line is that somehow,

this patch causes corruption when the numa balancing feature is

enabled AND we don't use process affinity AND we use GUP to pin pages

so our accelerator can DMA to/from system memory.

Either disabling numa balancing, using process affinity to bind to

specific numa-node or reverting this patch causes the bug to

disappear"

and Oded bisected the issue to commit 09854ba94c6a ("mm: do_wp_page()

simplification").

Now, the NUMA balancing shouldn't actually be changing the writability

of a page, and as such shouldn't matter for COW. But it appears it

does. Suspicious.

However, regardless of that, the condition for enabling NUMA faults in

change_pte_range() is nonsensical.

/// 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