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Alpine Linux: CVE-2023-46835: Vulnerability in Xen

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Alpine Linux: CVE-2023-46835: Vulnerability in Xen

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:C/I:N/A:N)
Published
01/05/2024
Created
04/09/2024
Added
03/26/2024
Modified
04/09/2024

Description

The current setup of the quarantine page tables assumes that the quarantine domain (dom_io) has been initialized with an address width of DEFAULT_DOMAIN_ADDRESS_WIDTH (48) and hence 4 page table levels. However dom_io being a PV domain gets the AMD-Vi IOMMU page tables levels based on the maximum (hot pluggable) RAM address, and hence on systems with no RAM above the 512GB mark only 3 page-table levels are configured in the IOMMU. On systems without RAM above the 512GB boundary amd_iommu_quarantine_init() will setup page tables for the scratch page with 4 levels, while the IOMMU will be configured to use 3 levels only, resulting in the last page table directory (PDE) effectively becoming a page table entry (PTE), and hence a device in quarantine mode gaining write access to the page destined to be a PDE. Due to this page table level mismatch, the sink page the device gets read/write access to is no longer cleared between device assignment, possibly leading to data leaks.

Solution(s)

  • alpine-linux-upgrade-xen

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