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high7.8

CVE-2024-35791

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 …

Impact

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

VendorProductAffected versions
LinuxLinux Kernel
from 4.19.176 before 4.20
from 5.4.98 before 5.5
from 5.10.15 before 5.10.215
from 5.11.1 before 5.15.154
from 5.16 before 6.1.84
from 6.2 before 6.6.24
DebianDebian Linux
Version 10.0

Weakness classification

CWE-416

References