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Red Hat: CVE-2024-35791: kernel: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() (Multiple Advisories)

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Red Hat: CVE-2024-35791: kernel: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() (Multiple Advisories)

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
05/17/2024
Created
07/26/2024
Added
07/25/2024
Modified
12/05/2024

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.

Solution(s)

  • redhat-upgrade-kernel
  • redhat-upgrade-kernel-rt

References

  • CVE-2024-35791
  • RHSA-2024:4823
  • RHSA-2024:4831
  • RHSA-2024:6567
  • 查看数 697
  • 已创建
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