nfsd: fix use-after-free due to delegation race (Linux Linux)

CVE-2021-47506
CRITICAL 9.8

En bref

Source
NVD
EPSS
EPSS 0.78 % · centile 56 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix use-after-free due to delegation race A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning.

Faiblesses (CWE)

  • CWE-416 — Utilisation après libération

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1CRITICAL 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected dff1399f8addf7129c49bb2227469da79cc30b47 < 04a8d07f3d58308b92630045560799a3faa3ebce ; affected dff1399f8addf7129c49bb2227469da79cc30b47 < 348714018139c39533c55661a0c7c990671396b4 ; affected dff1399f8addf7129c49bb2227469da79cc30b47 < 33645d3e22720cac1e4548f8fef57bf0649536ee ; affected dff1399f8addf7129c49bb2227469da79cc30b47 < 2becaa990b93cbd2928292c0b669d3abb6cf06d4 ; affected dff1399f8addf7129c49bb2227469da79cc30b47 < e0759696de6851d7536efddfdd2dfed4c4df1f09 ; affected dff1399f8addf7129c49bb2227469da79cc30b47 < eeb0711801f5e19ef654371b627682aed3b11373
Linux · Linuxaffected 3.17 ; unaffected 0 < 3.17 ; unaffected 4.4.296 ≤ 4.4.* ; unaffected 4.9.294 ≤ 4.9.* ; unaffected 4.14.259 ≤ 4.14.* ; unaffected 4.19.222 ≤ 4.19.*

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