An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15564
Reference (s):
- DEBIAN:DSA-4723
- URL: https://www.debian.org/security/2020/dsa-4723
- FEDORA:FEDORA-2020-76cf2b0f0a
- URL: https://lists.fedoraproject.org/archives/list/[email protected]/message/MXESCOVI7AVRNC7HEAMFM7PMEO6D3AUH/
- FEDORA:FEDORA-2020-fbc13516af