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mm/hugetlb: unshare page tables during VMA split, not before (Linux Linux)

CVE-2025-38084
HIGH 7.8

En bref

Source
NVD
EPSS
EPSS 0.20 % · centile 10 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Rechercher sur…

Description

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: unshare page tables during VMA split, not before Currently, __split_vma() triggers hugetlb page table unsharing through vm_ops->may_split(). This happens before the VMA lock and rmap locks are taken - which is too early, it allows racing VMA-locked page faults in our process and racing rmap walks from other processes to cause page tables to be shared again before we actually perform the split. Fix it by explicitly calling into the hugetlb unshare logic from __split_vma() in the same place where THP splitting also happens. At that point, both the VMA and the rmap(s) are write-locked. An annoying detail is that we can now call into the helper hugetlb_unshare_pmds() from two different locking contexts: 1. from hugetlb_split(), holding: - mmap lock (exclusively) - VMA lock - file rmap lock (exclusively) 2. hugetlb_unshare_all_pmds(), which I think is designed to be able to call us with only the mmap lock held (in shared mode), but currently only runs while holding mmap lock (exclusively) and VMA lock Backporting note: This commit fixes a racy protection that was introduced in commit b30c14cd6102 ("hugetlb: unshare some PMDs when splitting VMAs"); that commit claimed to fix an issue introduced in 5.13, but it should actually also go all the way back. [jannh@google.com: v2]

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/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 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < e8847d18cd9fff1edbb45e963d9141273c3b539c ; affected 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < 366298f2b04d2bf1f2f2b7078405bdf9df9bd5d0 ; affected 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < 2511ac64bc1617ca716d3ba8464e481a647c1902 ; affected 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < af6cfcd0efb7f051af221c418ec8b37a10211947 ; affected 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < 9cf5b2a3b72c23fb7b84736d5d19ee6ea718762b ; affected 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa < 8a21d5584826f4880f45bbf8f72375f4e6c0ff2a
Linux · Linuxaffected 2.6.20 ; unaffected 0 < 2.6.20 ; unaffected 5.10.239 ≤ 5.10.* ; unaffected 5.15.186 ≤ 5.15.* ; unaffected 6.1.142 ≤ 6.1.* ; unaffected 6.6.95 ≤ 6.6.*

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