CVE-2020-8834

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 4.18

Description The issue is caused by a conflicting use of HSTATE HOST R1 to store r1 state in kvmppc hv entry plus in kvmppc {save,restore} tm, leading to a stack corruption. An attacker with the ability to run code in kernel space of a guest VM can cause the host kernel to panic. The vulnerability was introduced by two commits that landed in versions 4.8 and 4.17.

Recommendations For Linux kernel versions prior to 4.18, update to version 4.18 or later to resolve the issue. As a temporary workaround, consider disabling the kvmppc save tm() and kvmppc restore tm() functions until a patch is available. Restrict access to the vulnerable kvmppc hv entry and kvmppc {save,restore} tm functions to minimize the risk of exploitation.