CVE-2024-26991

/// Technical description

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

KVM: x86/mmu: x86: Don't overflow lpage_info when checking attributes

Fix KVM_SET_MEMORY_ATTRIBUTES to not overflow lpage_info array and trigger

KASAN splat, as seen in the private_mem_conversions_test selftest.

When memory attributes are set on a GFN range, that range will have

specific properties applied to the TDP. A huge page cannot be used when

the attributes are inconsistent, so they are disabled for those the

specific huge pages. For internal KVM reasons, huge pages are also not

allowed to span adjacent memslots regardless of whether the backing memory

could be mapped as huge.

What GFNs support which huge page sizes is tracked by an array of arrays

'lpage_info' on the memslot, of ‘kvm_lpage_info’ structs. Each index of

lpage_info contains a vmalloc allocated array of these for a specific

supported page size. The kvm_lpage_info denotes whether a specific huge

page (GFN and page size) on the memslot is support

/// 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