| 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-2024-49872: mm/gup: fix memfd_pin_folios alloc race panic |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm/gup: fix memfd_pin_folios alloc race panic |
| |
| If memfd_pin_folios tries to create a hugetlb page, but someone else |
| already did, then folio gets the value -EEXIST here: |
| |
| folio = memfd_alloc_folio(memfd, start_idx); |
| if (IS_ERR(folio)) { |
| ret = PTR_ERR(folio); |
| if (ret != -EEXIST) |
| goto err; |
| |
| then on the next trip through the "while start_idx" loop we panic here: |
| |
| if (folio) { |
| folio_put(folio); |
| |
| To fix, set the folio to NULL on error. |
| |
| The Linux kernel CVE team has assigned CVE-2024-49872 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.11 with commit 89c1905d9c140372b7f50ef48f42378cf85d9bc5 and fixed in 6.11.3 with commit e28f39b359c0cfdcc011603e51187085a5f1e5e3 |
| Issue introduced in 6.11 with commit 89c1905d9c140372b7f50ef48f42378cf85d9bc5 and fixed in 6.12 with commit ce645b9fdc78ec5d28067286e92871ddae6817d5 |
| |
| 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-2024-49872 |
| 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: |
| mm/gup.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/e28f39b359c0cfdcc011603e51187085a5f1e5e3 |
| https://git.kernel.org/stable/c/ce645b9fdc78ec5d28067286e92871ddae6817d5 |
