CVE-2024-42102: Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"
In the Linux kernel, the following vulnerability has been resolved:
Revert "mm/writeback: fix possible divide-by-zero in wbdirtylimits(), 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 wbthresh bgthresh >= 1<<32 (which is actually common - the default settings with 4GB of RAM will trigger this). Secondly, the div64u64() is unnecessarily expensive on 32-bit archs. We have div64ul() 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.
Other sources
Revert "mm/writeback: fix possible divide-by-zero in wbdirtylimits() again"
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 4.19.318 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 5.4.280 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 5.10.222 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 5.15.163 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 6.1.98 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 6.6.39 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 6.9.9 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 6.10 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.98-1 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.9.9-1 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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Linux kernelto a version that resolves this vulnerability.Patch 9319b647902cbd5cc884ac08a8a6d54ce111fc78
Event History
Frequently Asked Questions
What is the severity of CVE-2024-42102?
CVE-2024-42102 has been classified as a moderate-severity vulnerability in the Linux kernel.
How do I fix CVE-2024-42102?
To fix CVE-2024-42102, update the Linux kernel to version 4.19.318, 5.4.280, 5.10.222, 5.15.163, 6.1.98, 6.6.39, 6.9.9, or 6.10 as appropriate.
What versions of the Linux kernel are affected by CVE-2024-42102?
CVE-2024-42102 affects versions of the Linux kernel prior to 4.19.318, 5.4.280, 5.10.222, 5.15.163, 6.1.98, 6.6.39, 6.9.9, and 6.10.
Is there a workaround for CVE-2024-42102?
There are no known workarounds for CVE-2024-42102; the recommended action is to apply the security updates.
Which distributions are impacted by CVE-2024-42102?
CVE-2024-42102 impacts distributions using the affected versions of the Linux kernel such as Red Hat and Debian.