Page Table Descriptor Integrity Verification
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Solution Overview
Problem
Data processing systems are vulnerable to memory corruption due to events like radiation strikes or malicious attacks, which can compromise the integrity of page table entries and their translation parameters, leading to unauthorized memory access.
Innovation Solution
Incorporating an integrity check value within page table descriptors that is dependent on the translation parameters, allowing for verification of descriptor integrity during memory access, and using a private key for secure integrity check value generation to protect against corruption and unauthorized modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If page table entries are stored in memory without integrity protection, then memory access speed is improved, but system security deteriorates due to vulnerability to memory corruption
Solution Approach 1:
The system performs preliminary integrity verification of page table descriptors by calculating an integrity verification value from translation parameters and comparing it with a stored integrity check value before using the page table entry. This preliminary check prevents corrupted entries from causing security violations, resolving the contradiction between fast access and reliable integrity protection.
2Reliability
If integrity verification is performed on all page table descriptors, then security is improved, but processing overhead increases
Solution Approach 1:
The integrity verification mechanism applies different treatment to different parts of the page table structure. The verification focuses specifically on the descriptor portion containing translation parameters, while the rest of the page table entry can be accessed without verification. This localized approach maintains security for critical data while minimizing processing overhead.
3Reliability
If page table descriptors are made immutable to prevent corruption, then integrity is improved, but flexibility in memory management deteriorates
Solution Approach 1:
The system dynamically manages page table descriptors by allowing modifications only when integrity verification passes and under controlled conditions. The integrity check value is updated whenever translation parameters are legitimately modified, enabling flexible memory management while maintaining continuous integrity protection. This dynamic approach resolves the contradiction between immutability for security and mutability for flexibility.
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
Apparatuses, methods, and programs for performing a translation of a virtual address of a memory access to a physical address associated with a memory location to be accessed are disclosed. A page table descriptor is accessed when performing the translation, which comprises translation parameters for the translation. The descriptor further comprises an integrity check value, wherein the integrity check value is dependent on the translation parameters.