Server Access Control via Base Address Register Toggling
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Solution Overview
Problem
In cloud computing environments, existing hypervisor protections are insufficient in some applications, necessitating alternative measures to prevent unwanted access to server hardware, especially when protections are removed.
Innovation Solution
A server computer toggles between a protected mode and an unprotected mode by modifying Base Address Registers (BARs) to control access, using separate interfaces for users and compute service providers, allowing secure access to configuration information and encryption keys while blocking unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hypervisor protections are removed to allow direct hardware access, then ease of operation is improved, but security is worsened
Solution Approach 1:
The patent segments the access control mechanism into multiple independent components: Base Address Registers (BARs) for configuration information access, and separate secure area protections for encryption keys. This segmentation allows different security levels to be applied to different hardware resources, enabling direct access to some components while protecting others.
Solution Approach 2:
The patent introduces an intermediary access control mechanism that sits between the user interface and the hardware resources. The BARs act as intermediaries that can be dynamically programmed to grant or deny access to configuration information, while a separate secure area intermediary protects encryption keys. This intermediary layer provides controlled access without requiring full hypervisor protection.
2Reliability
If Base Address Registers are cleared to block user access, then security is improved, but ease of operation is worsened
Solution Approach 1:
The patent implements dynamic access control by making the BARs programmable and toggleable. The access control mechanism can dynamically switch between protected and unprotected states based on operational requirements. This allows the system to adapt access levels in real-time, clearing BARs when security is needed and programming them when access is required.
Solution Approach 2:
The patent changes the parameter state of the BARs to control access. By clearing or programming specific parameters in the BARs, the system can switch between blocking and allowing access to configuration information. This parameter-based control provides a flexible mechanism to balance security and operational access.
3Reliability
If separate interfaces are used for user and service provider access, then security is improved, but device complexity is worsened
Solution Approach 1:
The patent applies local quality by giving different interfaces different access characteristics. The first interface (for users) has access controlled by BARs that can be cleared to block configuration access, while the second interface (for service providers) has access to a protected secure area containing encryption keys. Each interface is optimized for its specific purpose with appropriate security characteristics applied locally.
Data Source
AI summary
A server computer toggles between a protected mode and an unprotected mode. In the protected mode, users are unable to access configuration information due to a Base Address Register (BAR) being cleared. However, a service provider can access a Trusted Platform Module (TPM) through an Application Program Interface (API) request. In an unprotected mode, the BAR is programmed so that users can access the configuration information, but the TPM is blocked. Blocking of the TPM is achieved by changing a configuration file, which changes an overall image of the card. With the modified image not matching an original image, the TPM blocks access to data, such as encryption keys. Separate interfaces can be used for user access (PCIe) and service provider access (Ethernet) to the server computer. The server computer can then be toggled back to the protected mode by switching the configuration file to the original configuration file.