CVE-2022-49562

KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits

HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.27 % · percentile 20 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case.

References

Scores

VersionScoreVectorScored by
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)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected bd53cb35a3e9adb73a834a36586e9ad80e877767 < 38b888911e8dc89b89d8147cfb1d2dbe6373bf78 ; affected bd53cb35a3e9adb73a834a36586e9ad80e877767 < 8089e5e1d18402fb8152d6b6815450a36fffa9b0 ; affected bd53cb35a3e9adb73a834a36586e9ad80e877767 < f122dfe4476890d60b8c679128cd2259ec96a24c
Linux · Linuxaffected 5.2 ; unaffected 0 < 5.2 ; unaffected 5.17.13 ≤ 5.17.* ; unaffected 5.18.2 ≤ 5.18.* ; unaffected 5.19 ≤ *

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