| From bippy-7c5fe7eed585 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-2024-57942: netfs: Fix ceph copy to cache on write-begin |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfs: Fix ceph copy to cache on write-begin |
| |
| At the end of netfs_unlock_read_folio() in which folios are marked |
| appropriately for copying to the cache (either with by being marked dirty |
| and having their private data set or by having PG_private_2 set) and then |
| unlocked, the folio_queue struct has the entry pointing to the folio |
| cleared. This presents a problem for netfs_pgpriv2_write_to_the_cache(), |
| which is used to write folios marked with PG_private_2 to the cache as it |
| expects to be able to trawl the folio_queue list thereafter to find the |
| relevant folios, leading to a hang. |
| |
| Fix this by not clearing the folio_queue entry if we're going to do the |
| deprecated copy-to-cache. The clearance will be done instead as the folios |
| are written to the cache. |
| |
| This can be reproduced by starting cachefiles, mounting a ceph filesystem |
| with "-o fsc" and writing to it. |
| |
| The Linux kernel CVE team has assigned CVE-2024-57942 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.12 with commit ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and fixed in 6.12.10 with commit 43b8d3249b0b71bad239d42dbe08ce6c938ba000 |
| Issue introduced in 6.12 with commit ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and fixed in 6.13 with commit 38cf8e945721ffe708fa675507465da7f4f2a9f7 |
| |
| 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-2024-57942 |
| 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: |
| fs/netfs/read_collect.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/43b8d3249b0b71bad239d42dbe08ce6c938ba000 |
| https://git.kernel.org/stable/c/38cf8e945721ffe708fa675507465da7f4f2a9f7 |
