Debian: DSA-4564-1 Critical Update: Kernel Privilege Escalation

CVE-2018-12207

It was discovered that on Intel CPUs supporting hardware
virtualisation with Extended Page Tables (EPT), a guest VM may
manipulate the memory management hardware to cause a Machine Check
Error (MCE) and denial of service (hang or crash).

The guest triggers this error by changing page tables without a
TLB flush, so that both 4 KB and 2 MB entries for the same virtual
address are loaded into the instruction TLB (iTLB). This update
implements a mitigation in KVM that prevents guest VMs from
loading 2 MB entries into the iTLB. This will reduce performance
of guest VMs.

Further information on the mitigation can be found at

or in the linux-doc-4.9 or linux-doc-4.19 package.

A qemu update adding support for the PSCHANGE_MC_NO feature, which
allows to disable iTLB Multihit mitigations in nested hypervisors will be provided via DSA 4566-1.

Intel's explanation of the issue can be found at
.

CVE-2019-0154

Intel discovere...