| 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-2024-42131: mm: avoid overflows in dirty throttling logic |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm: avoid overflows in dirty throttling logic |
| |
| The dirty throttling logic is interspersed with assumptions that dirty |
| limits in PAGE_SIZE units fit into 32-bit (so that various multiplications |
| fit into 64-bits). If limits end up being larger, we will hit overflows, |
| possible divisions by 0 etc. Fix these problems by never allowing so |
| large dirty limits as they have dubious practical value anyway. For |
| dirty_bytes / dirty_background_bytes interfaces we can just refuse to set |
| so large limits. For dirty_ratio / dirty_background_ratio it isn't so |
| simple as the dirty limit is computed from the amount of available memory |
| which can change due to memory hotplug etc. So when converting dirty |
| limits from ratios to numbers of pages, we just don't allow the result to |
| exceed UINT_MAX. |
| |
| This is root-only triggerable problem which occurs when the operator |
| sets dirty limits to >16 TB. |
| |
| The Linux kernel CVE team has assigned CVE-2024-42131 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.19.320 with commit 2b2d2b8766db028bd827af34075f221ae9e9efff |
| Fixed in 5.4.282 with commit 4d3817b64eda07491bdd86a234629fe0764fb42a |
| Fixed in 5.10.222 with commit 7a49389771ae7666f4dc3426e2a4594bf23ae290 |
| Fixed in 5.15.163 with commit a25e8536184516b55ef89ab91dd2eea429de28d2 |
| Fixed in 6.1.98 with commit c83ed422c24f0d4b264f89291d4fabe285f80dbc |
| Fixed in 6.6.39 with commit bd16a7ee339aef3ee4c90cb23902afb6af379ea0 |
| Fixed in 6.9.9 with commit 8e0b5e7f2895eccef5c2a0018b589266f90c4805 |
| Fixed in 6.10 with commit 385d838df280eba6c8680f9777bfa0d0bfe7e8b2 |
| |
| 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-2024-42131 |
| 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/page-writeback.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/2b2d2b8766db028bd827af34075f221ae9e9efff |
| https://git.kernel.org/stable/c/4d3817b64eda07491bdd86a234629fe0764fb42a |
| https://git.kernel.org/stable/c/7a49389771ae7666f4dc3426e2a4594bf23ae290 |
| https://git.kernel.org/stable/c/a25e8536184516b55ef89ab91dd2eea429de28d2 |
| https://git.kernel.org/stable/c/c83ed422c24f0d4b264f89291d4fabe285f80dbc |
| https://git.kernel.org/stable/c/bd16a7ee339aef3ee4c90cb23902afb6af379ea0 |
| https://git.kernel.org/stable/c/8e0b5e7f2895eccef5c2a0018b589266f90c4805 |
| https://git.kernel.org/stable/c/385d838df280eba6c8680f9777bfa0d0bfe7e8b2 |
