CVE-2021-47255 Information

Description

In the Linux kernel the following vulnerability has been resolved:

kvm: LAPIC: Restore guard to prevent illegal APIC register access

Per the SDM ny access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed.\nWorse such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 (\kvm: LAPIC: write down valid APIC registers) such an access was explicitly disallowed. Restore the guard that was removed in that commit.

Reference

https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84 https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5 https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210 https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6