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Unrated severityNVD Advisory· Published May 17, 2024· Updated May 4, 2025

KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()

CVE-2024-35791

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.

Affected products

178

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

6

News mentions

0

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