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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database

Vulnerability Change Records for CVE-2023-46835

Change History

New CVE Received by NIST 1/05/2024 12:15:11 PM

Action Type Old Value New Value
Added 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.


								
								
					

					

						Added
						Reference
						
							
							
								
							
								

								
							
							
								
							
						
								
							
								
Xen Project https://xenbits.xenproject.org/xsa/advisory-445.html [No types assigned]