| 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-2021-47035: iommu/vt-d: Remove WO permissions on second-level paging entries |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| iommu/vt-d: Remove WO permissions on second-level paging entries |
| |
| When the first level page table is used for IOVA translation, it only |
| supports Read-Only and Read-Write permissions. The Write-Only permission |
| is not supported as the PRESENT bit (implying Read permission) should |
| always set. When using second level, we still give separate permissions |
| that allows WriteOnly which seems inconsistent and awkward. We want to |
| have consistent behavior. After moving to 1st level, we don't want things |
| to work sometimes, and break if we use 2nd level for the same mappings. |
| Hence remove this configuration. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47035 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.6 with commit b802d070a52a1565b47daaa808872cfbd4a17b01 and fixed in 5.10.38 with commit 89bd620798704a8805fc9db0d71d7f812cf5b3d2 |
| Issue introduced in 5.6 with commit b802d070a52a1565b47daaa808872cfbd4a17b01 and fixed in 5.11.21 with commit 25faff78138933244c678c7fc78f7c0340fa04a0 |
| Issue introduced in 5.6 with commit b802d070a52a1565b47daaa808872cfbd4a17b01 and fixed in 5.12.4 with commit 66c24699f266ff310381a9552d3576eea8ad6e20 |
| Issue introduced in 5.6 with commit b802d070a52a1565b47daaa808872cfbd4a17b01 and fixed in 5.13 with commit eea53c5816889ee8b64544fa2e9311a81184ff9c |
| |
| 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-2021-47035 |
| 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/iommu/intel/iommu.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/89bd620798704a8805fc9db0d71d7f812cf5b3d2 |
| https://git.kernel.org/stable/c/25faff78138933244c678c7fc78f7c0340fa04a0 |
| https://git.kernel.org/stable/c/66c24699f266ff310381a9552d3576eea8ad6e20 |
| https://git.kernel.org/stable/c/eea53c5816889ee8b64544fa2e9311a81184ff9c |
