| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26918: PCI: Fix active state requirement in PME polling |
| |
| 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 reported in the bugzilla below where a |
| Thunderbolt/USB4 hierarchy fails to scan for an attached NVMe endpoint |
| downstream of a bridge in a D3hot power state. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26918 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.6 with commit d3fcd7360338358aa0036bec6d2cf0e37a0ca624 and fixed in 6.6.18 with commit 63b1a3d9dd3b3f6d67f524e76270e66767090583 |
| Issue introduced in 6.6 with commit d3fcd7360338358aa0036bec6d2cf0e37a0ca624 and fixed in 6.7.6 with commit a4f12e5cbac2865c151d1e97e36eb24205afb23b |
| Issue introduced in 6.6 with commit d3fcd7360338358aa0036bec6d2cf0e37a0ca624 and fixed in 6.8 with commit 41044d5360685e78a869d40a168491a70cdb7e73 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-26918 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/pci/pci.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/63b1a3d9dd3b3f6d67f524e76270e66767090583 |
| https://git.kernel.org/stable/c/a4f12e5cbac2865c151d1e97e36eb24205afb23b |
| https://git.kernel.org/stable/c/41044d5360685e78a869d40a168491a70cdb7e73 |
