Vulnerability in Kernel: iommu/vt-d - Remove WO permissions on second-level paging entries
Summary
GSD-2021-1000260: iommu/vt-d: Remove WO permissions on second-level paging entries. Affects Kernel versions >= b802d070a52a1565b47daaa808872cfbd4a17b01, < 66c24699f266ff310381a9552d3576eea8ad6e20. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that provides core functionality and acts as an interface between hardware and software. It manages system resources, facilitates communication between different software components, and ensures the security and stability of the system. The iommu/vt-d subsystem in the Kernel is responsible for handling input-output memory management unit (IOMMU) operations and virtualization technology for directed I/O (VT-d). It provides hardware support for isolating and protecting memory regions used by devices. However, a vulnerability has been discovered in the iommu/vt-d subsystem that allows unauthorized write access to second-level paging entries, potentially leading to security breaches and system compromise.
Vulnerability Detail
The vulnerability in the iommu/vt-d subsystem arises from the presence of write-only (WO) permissions on second-level paging entries. This allows an attacker with access to the system to modify these entries, potentially leading to unauthorized changes in memory mappings and compromising the security of the system. The impact and attack plausibility of this vulnerability have not been proven yet, but it poses a potential risk to the integrity and confidentiality of data. The vulnerability was introduced in version v5.6 of the Linux Kernel and has been fixed in version v5.12.4.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can apply patches or backports provided by the Linux distribution maintainers. These patches may include specific fixes for the iommu/vt-d subsystem vulnerability. It is important to follow the instructions provided by the distribution maintainers to ensure proper application of the patches.
Conclusion
The vulnerability in the iommu/vt-d subsystem of the Linux Kernel can potentially allow unauthorized write access to second-level paging entries, compromising the security of the system. It is crucial to update the Kernel to version v5.12.4 or later to mitigate this vulnerability. Applying patches or backports provided by the Linux distribution maintainers can serve as a temporary workaround. For further support on vulnerability remediation, you can contact DevNack.com.
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FAQ
The iommu/vt-d subsystem in the Linux Kernel provides hardware support for isolating and protecting memory regions used by devices. It enables secure memory management in systems with input-output memory management units (IOMMUs) and virtualization technology for directed I/O (VT-d).
The vulnerability allows unauthorized write access to second-level paging entries in the iommu/vt-d subsystem. This can potentially lead to unauthorized changes in memory mappings and compromise the security of the system.
To fix this vulnerability, it is recommended to update the Linux Kernel to version v5.12.4 or later. This update includes the necessary changes to remove the write-only permissions on second-level paging entries in the iommu/vt-d subsystem.
Yes, users can apply patches or backports provided by the Linux distribution maintainers as a temporary workaround. These patches may include specific fixes for the iommu/vt-d subsystem vulnerability.
You can find more information about this vulnerability in the official Linux Kernel documentation and security advisories. Additionally, you can use tools like Vulert to monitor and alert for open-source vulnerabilities in your software.
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