CVE-2024-42102: Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"
First published: Tue Jul 30 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=4.19.307<4.19.318 | |
| Linux Linux kernel | >=5.4.269<5.4.280 | |
| Linux Linux kernel | >=5.10.210<5.10.222 | |
| Linux Linux kernel | >=5.15.149<5.15.163 | |
| Linux Linux kernel | >=6.1.79<6.1.98 | |
| Linux Linux kernel | >=6.6.18<6.6.39 | |
| Linux Linux kernel | >=6.8<6.9.9 | |
| redhat/kernel | <4.19.318 | 4.19.318 |
| redhat/kernel | <5.4.280 | 5.4.280 |
| redhat/kernel | <5.10.222 | 5.10.222 |
| redhat/kernel | <5.15.163 | 5.15.163 |
| redhat/kernel | <6.1.98 | 6.1.98 |
| redhat/kernel | <6.6.39 | 6.6.39 |
| redhat/kernel | <6.9.9 | 6.9.9 |
| redhat/kernel | <6.10 | 6.10 |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://git.kernel.org/stable/c/000099d71648504fb9c7a4616f92c2b70c3e44ec
- https://git.kernel.org/stable/c/145faa3d03688cbb7bbaaecbd84c01539852942c
- https://git.kernel.org/stable/c/23a28f5f3f6ca1e4184bd0e9631cd0944cf1c807
- https://git.kernel.org/stable/c/253f9ea7e8e53a5176bd80ceb174907b10724c1a
- https://git.kernel.org/stable/c/2820005edae13b140f2d54267d1bd6bb23915f59
- https://git.kernel.org/stable/c/30139c702048f1097342a31302cbd3d478f50c63
- https://git.kernel.org/stable/c/cbbe17a324437c0ff99881a3ee453da45b228a00
- https://git.kernel.org/stable/c/f6620df12cb6bdcad671d269debbb23573502f9d
- https://git.kernel.org/linus/30139c702048f1097342a31302cbd3d478f50c63
- https://security-tracker.debian.org/tracker/CVE-2024-42102
- https://lore.kernel.org/linux-cve-announce/2024073019-CVE-2024-42102-bcee@gregkh/T
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2301760
- https://access.redhat.com/errata/RHSA-2024:6268
- https://access.redhat.com/errata/RHSA-2024:6267
- https://access.redhat.com/errata/RHSA-2024:6567
- https://bugzilla.redhat.com/show_bug.cgi?id=2301465
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-42102
- https://nvd.nist.gov/vuln/detail/CVE-2024-42102
- https://launchpad.net/bugs/cve/CVE-2024-42102
- https://ubuntu.com/security/CVE-2024-42102
- agent/title
- agent/type
- collector/nvd-api
- source/NVD
- agent/software-canonical-lookup
- agent/weakness
- agent/severity
- collector/mitre-cve
- source/MITRE
- agent/remedy
- agent/references
- agent/first-publish-date
- collector/security-tracker-debian
- source/Debian
- agent/author
- agent/description
- agent/event
- collector/nvd-cve
- agent/softwarecombine
- agent/tags
- collector/redhat-bugzilla
- source/Red Hat
- alias/CVE-2024-42102
- agent/last-modified-date
- collector/usn-cve
- source/Ubuntu
- vendor/linux
- canonical/linux linux kernel
- version/linux linux kernel/4.19.307
- version/linux linux kernel/5.4.269
- version/linux linux kernel/5.10.210
- version/linux linux kernel/5.15.149
- version/linux linux kernel/6.1.79
- version/linux linux kernel/6.6.18
- version/linux linux kernel/6.8
- package-manager/debian
- package-manager/redhat