CVE-2024-26918

/// Technical description

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

PCI: Fix active state requirement in PME polling

The commit noted in fixes added a bogus requirement that runtime PM managed

devices need to be in the RPM_ACTIVE state for PME polling. In fact, only

devices in low power states should be polled.

However there's still a requirement that the device config space must be

accessible, which has implications for both the current state of the polled

device and the parent bridge, when present. It's not sufficient to assume

the bridge remains in D0 and cases have been observed where the bridge

passes the D0 test, but the PM state indicates RPM_SUSPENDING and config

space of the polled device becomes inaccessible during pci_pme_wakeup().

Therefore, since the bridge is already effectively required to be in the

RPM_ACTIVE state, formalize this in the code and elevate the PM usage count

to maintain the state while polling the subordinate device.

This resolves a regression repo

/// 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