Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again" (Linux Linux)

CVE-2024-42102
MEDIUM 4.7

En bref

Source
NVD
EPSS
EPSS 0.26 % · centile 17 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

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.

Faiblesses (CWE)

  • CWE-369 — Division par zéro

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1MEDIUM 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected c593d26fb5d577ef31b6e49a31e08ae3ebc1bc1e < 253f9ea7e8e53a5176bd80ceb174907b10724c1a ; affected 1f12e4b3284d6c863f272eb2de0d4248ed211cf4 < 23a28f5f3f6ca1e4184bd0e9631cd0944cf1c807 ; affected 81e7d2530d458548b90a5c5e76b77ad5e5d1c0df < 145faa3d03688cbb7bbaaecbd84c01539852942c ; affected 5099871b370335809c0fd1abad74d9c7c205d43f < 2820005edae13b140f2d54267d1bd6bb23915f59 ; affected 16b1025eaa8fc223ab4273ece20d1c3a4211a95d < cbbe17a324437c0ff99881a3ee453da45b228a00 ; affected ec18ec230301583395576915d274b407743d8f6c < f6620df12cb6bdcad671d269debbb23573502f9d
Linux · Linuxaffected 6.8 ; unaffected 0 < 6.8 ; unaffected 4.19.318 ≤ 4.19.* ; unaffected 5.4.280 ≤ 5.4.* ; unaffected 5.10.222 ≤ 5.10.* ; unaffected 5.15.163 ≤ 5.15.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD