Oracle Linux: CVE-2018-18021: ELSA-2018-4270: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

Description

arch/arm64/kvm/guest.c in KVM in the Linux kernel before 4.18.12 on the arm64 platform mishandles the KVM_SET_ON_REG ioctl. This is exploitable by attackers who can create virtual machines. An attacker can arbitrarily redirect the hypervisor flow of control (with full register control). An attacker can also cause a denial of service (hypervisor panic) via an illegal exception return. This occurs because of insufficient restrictions on userspace access to the core register file, and because PSTATE.M validation does not prevent unintended execution modes. A vulnerability was discovered in the Linux kernel that allows an attacker to escalate privileges with using a 64-bit ARM architecture. A local attacker with permission to create KVM-based virtual machines can both panic the hypervisor by triggering an illegal exception return (resulting in a DoS) and to redirect execution elsewhere within the hypervisor with full register control, instead of causing a return to the guest.