| 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-2024-26630: mm: cachestat: fix folio read-after-free in cache walk |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm: cachestat: fix folio read-after-free in cache walk |
| |
| In cachestat, we access the folio from the page cache's xarray to compute |
| its page offset, and check for its dirty and writeback flags. However, we |
| do not hold a reference to the folio before performing these actions, |
| which means the folio can concurrently be released and reused as another |
| folio/page/slab. |
| |
| Get around this altogether by just using xarray's existing machinery for |
| the folio page offsets and dirty/writeback states. |
| |
| This changes behavior for tmpfs files to now always report zeroes in their |
| dirty and writeback counters. This is okay as tmpfs doesn't follow |
| conventional writeback cache behavior: its pages get "cleaned" during |
| swapout, after which they're no longer resident etc. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26630 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.5 with commit cf264e1329fb0307e044f7675849f9f38b44c11a and fixed in 6.6.21 with commit ba60fdf75e89ea762bb617be578dc47f27655117 |
| Issue introduced in 6.5 with commit cf264e1329fb0307e044f7675849f9f38b44c11a and fixed in 6.7.9 with commit fe7e008e0ce728252e4ec652cceebcc62211657c |
| Issue introduced in 6.5 with commit cf264e1329fb0307e044f7675849f9f38b44c11a and fixed in 6.8 with commit 3a75cb05d53f4a6823a32deb078de1366954a804 |
| |
| 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-2024-26630 |
| 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/filemap.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/ba60fdf75e89ea762bb617be578dc47f27655117 |
| https://git.kernel.org/stable/c/fe7e008e0ce728252e4ec652cceebcc62211657c |
| https://git.kernel.org/stable/c/3a75cb05d53f4a6823a32deb078de1366954a804 |
