| 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-2024-42102: Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again" |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again" |
| |
| Patch series "mm: Avoid possible overflows in dirty throttling". |
| |
| Dirty throttling logic assumes dirty limits in page units fit into |
| 32-bits. This patch series makes sure this is true (see patch 2/2 for |
| more details). |
| |
| |
| This patch (of 2): |
| |
| This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78. |
| |
| The commit is broken in several ways. Firstly, the removed (u64) cast |
| from the multiplication will introduce a multiplication overflow on 32-bit |
| archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the |
| default settings with 4GB of RAM will trigger this). Secondly, the |
| div64_u64() is unnecessarily expensive on 32-bit archs. We have |
| div64_ul() in case we want to be safe & cheap. Thirdly, if dirty |
| thresholds are larger than 1<<32 pages, then dirty balancing is going to |
| blow up in many other spectacular ways anyway so trying to fix one |
| possible overflow is just moot. |
| |
| The Linux kernel CVE team has assigned CVE-2024-42102 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.19.307 with commit c593d26fb5d577ef31b6e49a31e08ae3ebc1bc1e and fixed in 4.19.318 with commit 253f9ea7e8e53a5176bd80ceb174907b10724c1a |
| Issue introduced in 5.4.269 with commit 1f12e4b3284d6c863f272eb2de0d4248ed211cf4 and fixed in 5.4.280 with commit 23a28f5f3f6ca1e4184bd0e9631cd0944cf1c807 |
| Issue introduced in 5.10.210 with commit 81e7d2530d458548b90a5c5e76b77ad5e5d1c0df and fixed in 5.10.222 with commit 145faa3d03688cbb7bbaaecbd84c01539852942c |
| Issue introduced in 5.15.149 with commit 5099871b370335809c0fd1abad74d9c7c205d43f and fixed in 5.15.163 with commit 2820005edae13b140f2d54267d1bd6bb23915f59 |
| Issue introduced in 6.1.79 with commit 16b1025eaa8fc223ab4273ece20d1c3a4211a95d and fixed in 6.1.98 with commit cbbe17a324437c0ff99881a3ee453da45b228a00 |
| Issue introduced in 6.6.18 with commit ec18ec230301583395576915d274b407743d8f6c and fixed in 6.6.39 with commit f6620df12cb6bdcad671d269debbb23573502f9d |
| Issue introduced in 6.8 with commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78 and fixed in 6.9.9 with commit 000099d71648504fb9c7a4616f92c2b70c3e44ec |
| Issue introduced in 6.8 with commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78 and fixed in 6.10 with commit 30139c702048f1097342a31302cbd3d478f50c63 |
| Issue introduced in 6.7.6 with commit 65977bed167a92e87085e757fffa5798f7314c9f |
| |
| 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-2024-42102 |
| 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/253f9ea7e8e53a5176bd80ceb174907b10724c1a |
| https://git.kernel.org/stable/c/23a28f5f3f6ca1e4184bd0e9631cd0944cf1c807 |
| https://git.kernel.org/stable/c/145faa3d03688cbb7bbaaecbd84c01539852942c |
| https://git.kernel.org/stable/c/2820005edae13b140f2d54267d1bd6bb23915f59 |
| https://git.kernel.org/stable/c/cbbe17a324437c0ff99881a3ee453da45b228a00 |
| https://git.kernel.org/stable/c/f6620df12cb6bdcad671d269debbb23573502f9d |
| https://git.kernel.org/stable/c/000099d71648504fb9c7a4616f92c2b70c3e44ec |
| https://git.kernel.org/stable/c/30139c702048f1097342a31302cbd3d478f50c63 |
