CVE-2024-31145 Affecting xen package, versions <4.18.3-r0

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Alpine. See How to fix? for Alpine:3.20 relevant fixed versions and status.

Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Reserved Memory Region Reporting, "RMRR") for Intel VT-d or Unity Mapping ranges for AMD-Vi. These are typically used for platform tasks such as legacy USB emulation.

Since the precise purpose of these regions is unknown, once a device associated with such a region is active, the mappings of these regions need to remain continuouly accessible by the device. In the logic establishing these mappings, error handling was flawed, resulting in such mappings to potentially remain in place when they should have been removed again. Respective guests would then gain access to memory regions which they aren't supposed to have access to.

• https://xenbits.xenproject.org/xsa/advisory-460.html
• http://www.openwall.com/lists/oss-security/2024/08/14/2
• http://xenbits.xen.org/xsa/advisory-460.html