| 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-2024-26990: KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| KVM: x86/mmu: Write-protect L2 SPTEs in TDP MMU when clearing dirty status |
| |
| Check kvm_mmu_page_ad_need_write_protect() when deciding whether to |
| write-protect or clear D-bits on TDP MMU SPTEs, so that the TDP MMU |
| accounts for any role-specific reasons for disabling D-bit dirty logging. |
| |
| Specifically, TDP MMU SPTEs must be write-protected when the TDP MMU is |
| being used to run an L2 (i.e. L1 has disabled EPT) and PML is enabled. |
| KVM always disables PML when running L2, even when L1 and L2 GPAs are in |
| the some domain, so failing to write-protect TDP MMU SPTEs will cause |
| writes made by L2 to not be reflected in the dirty log. |
| |
| [sean: massage shortlog and changelog, tweak ternary op formatting] |
| |
| The Linux kernel CVE team has assigned CVE-2024-26990 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.4 with commit 5982a5392663b30f57ee90b0372c19a7e9cb655a and fixed in 6.6.29 with commit cdf811a937471af2d1facdf8ae80e5e68096f1ed |
| Issue introduced in 6.4 with commit 5982a5392663b30f57ee90b0372c19a7e9cb655a and fixed in 6.8.8 with commit e20bff0f1b2de9cfe303dd35ff46470104a87404 |
| Issue introduced in 6.4 with commit 5982a5392663b30f57ee90b0372c19a7e9cb655a and fixed in 6.9 with commit 2673dfb591a359c75080dd5af3da484b89320d22 |
| |
| 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-2024-26990 |
| 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: |
| arch/x86/kvm/mmu/tdp_mmu.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/cdf811a937471af2d1facdf8ae80e5e68096f1ed |
| https://git.kernel.org/stable/c/e20bff0f1b2de9cfe303dd35ff46470104a87404 |
| https://git.kernel.org/stable/c/2673dfb591a359c75080dd5af3da484b89320d22 |
