CVE-2024-35791

medium

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() Do the cache flush of converted pages in svm_register_enc_region() before dropping kvm->lock to fix use-after-free issues where region and/or its array of pages could be freed by a different task, e.g. if userspace has __unregister_enc_region_locked() already queued up for the region. Note, the "obvious" alternative of using local variables doesn't fully resolve the bug, as region->pages is also dynamically allocated. I.e. the region structure itself would be fine, but region->pages could be freed. Flushing multiple pages under kvm->lock is unfortunate, but the entire flow is a rare slow path, and the manual flush is only needed on CPUs that lack coherency for encrypted memory.

References

https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html

https://git.kernel.org/stable/c/f6d53d8a2617dd58c89171a6b9610c470ebda38a

https://git.kernel.org/stable/c/e126b508ed2e616d679d85fca2fbe77bb48bbdd7

https://git.kernel.org/stable/c/5ef1d8c1ddbf696e47b226e11888eaf8d9e8e807

https://git.kernel.org/stable/c/4868c0ecdb6cfde7c70cf478c46e06bb9c7e5865

https://git.kernel.org/stable/c/2d13b79640b147bd77c34a5998533b2021a4122d

https://git.kernel.org/stable/c/12f8e32a5a389a5d58afc67728c76e61beee1ad4

Details

Source: Mitre, NVD

Published: 2024-05-17

Updated: 2024-06-25

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 5.5

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium