CVE-2024-35980

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

arm64: tlb: Fix TLBI RANGE operand

KVM/arm64 relies on TLBI RANGE feature to flush TLBs when the dirty

pages are collected by VMM and the page table entries become write

protected during live migration. Unfortunately, the operand passed

to the TLBI RANGE instruction isn't correctly sorted out due to the

commit 117940aa6e5f ("KVM: arm64: Define kvm_tlb_flush_vmid_range()").

It leads to crash on the destination VM after live migration because

TLBs aren't flushed completely and some of the dirty pages are missed.

For example, I have a VM where 8GB memory is assigned, starting from

0x40000000 (1GB). Note that the host has 4KB as the base page size.

In the middile of migration, kvm_tlb_flush_vmid_range() is executed

to flush TLBs. It passes MAX_TLBI_RANGE_PAGES as the argument to

__kvm_tlb_flush_vmid_range() and __flush_s2_tlb_range_op(). SCALE#3

and NUM#31, corresponding to MAX_TLBI_RANGE_PAGES, isn't supported

by __TLB

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References