CVE-2024-35791

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> KVM: SVM: Flush pages under kvm-&gt;lock to fix UAF in svm_register_enc_region()<br /> <br /> Do the cache flush of converted pages in svm_register_enc_region() before<br /> dropping kvm-&gt;lock to fix use-after-free issues where region and/or its<br /> array of pages could be freed by a different task, e.g. if userspace has<br /> __unregister_enc_region_locked() already queued up for the region.<br /> <br /> Note, the "obvious" alternative of using local variables doesn&amp;#39;t fully<br /> resolve the bug, as region-&gt;pages is also dynamically allocated. I.e. the<br /> region structure itself would be fine, but region-&gt;pages could be freed.<br /> <br /> Flushing multiple pages under kvm-&gt;lock is unfortunate, but the entire<br /> flow is a rare slow path, and the manual flush is only needed on CPUs that<br /> lack coherency for encrypted memory.