CVE-2023-46835 | Date: (C)2023-12-21 (M)2024-06-14 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 5.5 | CVSS Score : |
Exploit Score: 1.8 | Exploit Score: |
Impact Score: 3.6 | Impact Score: |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: LOCAL | Access Vector: |
Attack Complexity: LOW | Access Complexity: |
Privileges Required: LOW | Authentication: |
User Interaction: NONE | Confidentiality: |
Scope: UNCHANGED | Integrity: |
Confidentiality: HIGH | Availability: |
Integrity: NONE | |
Availability: NONE | |
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