I/O Device Emulation Using Protected Registers for Secure Access
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Solution Overview
Problem
Existing computing systems face vulnerabilities as malicious entities can exploit I/O devices to obtain secure data, tamper with it, or cause damage, necessitating improved secure computing management techniques to protect these devices.
Innovation Solution
Implementing a secure computing management technique that involves storing I/O device access rights in a protected memory portion, accessing these rights securely, and emulating I/O device registers to control software access, using microcode patches and memory encryption to isolate and manage I/O device access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If I/O devices are made accessible to software for normal operation, then system functionality and ease of operation are improved, but security vulnerability increases allowing malicious access to secure data
Solution Approach 1:
The patent introduces an intermediary mechanism (I/O access rights stored in protected memory and emulated registers) that mediates between software and I/O devices. This intermediary controls and filters access requests, allowing legitimate software to communicate with I/O devices while blocking malicious access attempts, thus resolving the contradiction between operational ease and security.
Solution Approach 2:
The patent segments the I/O access control mechanism into multiple components: access rights stored in protected memory portions, emulated register interfaces, and microcode-level control. This segmentation allows different levels of access control and isolation, enabling secure data protection while maintaining necessary I/O functionality for legitimate operations.
2Reliability
If access control mechanisms are implemented to protect I/O devices, then security is improved, but system complexity increases
Solution Approach 1:
The patent uses copying by creating emulated versions of I/O registers in protected memory. These emulated registers replicate the functionality of physical I/O registers but operate within the secure boundary, allowing access control logic to be implemented in software/firmware rather than requiring complex hardware modifications, thus improving security while managing complexity.
Solution Approach 2:
The patent replaces complex hardware-based access control mechanisms with microcode and software-based emulation. By substituting mechanical/hardware control with firmware-level emulation of I/O registers and access rights management, the system achieves enhanced security control without proportionally increasing hardware complexity.
3Reliability
If emulated registers are used to control I/O access, then security is improved, but processing overhead increases
Solution Approach 1:
The patent implements preliminary action by pre-storing I/O access rights in protected memory portions before runtime operations. Access control decisions are based on pre-established rights and policies, allowing the system to quickly evaluate access requests without complex real-time analysis, thus improving security enforcement while minimizing processing overhead during actual I/O operations.
Data Source
AI summary
A system is disclosed for Input/Output (I/O) device emulation that allows a service provider to configure and enforce a policy for software access to some or all I/O resources in a platform. I/O device emulation enables service providers to protect their platforms from malicious guest software that may be executed on associated platforms that has direct access to I/O resources in case of bare-metal servers, escalates the privilege level from guest to host in case of hosted-Virtual Machine servers, or escalates the privilege level from guest to System Management Mode in case of either bare-metal servers or hosted-Virtual Machine servers. The technology enables service providers to protect their platforms from malicious guest software running on their platforms that either has direct access to legacy I/O and memory mapped I/O resources. In one illustrative example, the platform may include a microprocessor.