CVE-2024-35804

KVM: x86: Mark target gfn of emulated atomic instruction as dirty

HIGH 8.8

At a glance

Source
NVD
EPSS
EPSS 0.24 % · percentile 15 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Mark target gfn of emulated atomic instruction as dirty When emulating an atomic access on behalf of the guest, mark the target gfn dirty if the CMPXCHG by KVM is attempted and doesn't fault. This fixes a bug where KVM effectively corrupts guest memory during live migration by writing to guest memory without informing userspace that the page is dirty. Marking the page dirty got unintentionally dropped when KVM's emulated CMPXCHG was converted to do a user access. Before that, KVM explicitly mapped the guest page into kernel memory, and marked the page dirty during the unmap phase. Mark the page dirty even if the CMPXCHG fails, as the old data is written back on failure, i.e. the page is still written. The value written is guaranteed to be the same because the operation is atomic, but KVM's ABI is that all writes are dirty logged regardless of the value written. And more importantly, that's what KVM did before the buggy commit. Huge kudos to the folks on the Cc list (and many others), who did all the actual work of triaging and debugging. base-commit: 6769ea8da8a93ed4630f1ce64df6aafcaabfce64

Weaknesses (CWE)

  • CWE-401 — Missing Release of Memory after Effective Lifetime

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HLinux
CVSS 3.1HIGH 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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 d97c0667c1e61ded6639117b4b9584a9c12b7e66 < a9bd6bb6f02bf7132c1ab192ba62bbfa52df7d66 ; affected 1c2361f667f3648855ceae25f1332c18413fdb9f < 726374dde5d608b15b9756bd52b6fc283fda7a06 ; affected 1c2361f667f3648855ceae25f1332c18413fdb9f < 9d1b22e573a3789ed1f32033ee709106993ba551 ; affected 1c2361f667f3648855ceae25f1332c18413fdb9f < 225d587a073584946c05c9b7651d637bd45c0c71 ; affected 1c2361f667f3648855ceae25f1332c18413fdb9f < 910c57dfa4d113aae6571c2a8b9ae8c430975902 ; affected b0f294103f4cf733e23d3f0c4e5fd58e42998921
Linux · Linuxaffected 5.19 ; unaffected 0 < 5.19 ; unaffected 5.15.154 ≤ 5.15.* ; unaffected 6.1.84 ≤ 6.1.* ; unaffected 6.6.24 ≤ 6.6.* ; unaffected 6.7.12 ≤ 6.7.*

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