Virtualized Environment DMA Access Control Module
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Solution Overview
Problem
Virtualization systems face security issues due to uncontrolled direct memory access (DMA) by domains, leading to potential malicious access and system failures, as the virtual machine monitor (VMM) lacks effective access control, allowing insecure domains to access physical memory and causing system resource overuse and event channel limitations.
Innovation Solution
Implementing an access control module within a control unit to manage DMA drivers and system resources, enforcing access policies to restrict malicious access by allocating I/O spaces, IRQ numbers, and system resources based on predetermined quotas, ensuring secure access and preventing excessive usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the domain unit processes DMA without access control, then system resource access is simplified and easier to implement, but security is compromised allowing malicious domains to access physical memory and cause system failures
Solution Approach 1:
The patent introduces an access control module as an intermediary between the domain unit and system resource unit. This module intercepts and controls all access requests, examining whether domains have authorization to access specific resources. By placing this mediator layer, the system maintains simplified DMA processing while adding security oversight, resolving the contradiction between ease of operation and system security.
2Device complexity
If the VMM performs simple access control, then implementation complexity is reduced, but malicious domains can excessively use system memory reducing system availability
Solution Approach 1:
The access control module dynamically adjusts access permissions based on domain credentials and resource requirements. Rather than static simple control, the system evaluates each access request in real-time, allowing legitimate high-resource operations while blocking malicious ones. This dynamic approach maintains reasonable implementation complexity while significantly improving system availability by preventing resource exhaustion attacks.
3Device complexity
If event channels are limited between domains, then system resource management is simplified, but malicious domains can exhaust all channels preventing communication between remaining domains
Solution Approach 1:
The access control module performs preliminary authorization checks before allocating event channels to domains. By evaluating domain credentials and communication requirements in advance, the system allocates channels appropriately without over-provisioning. This prevents malicious domains from exhausting channels while maintaining simplified channel management through proactive resource allocation rather than reactive limitation.
Data Source
AI summary
Provided is an apparatus and method for protecting a system in a virtualized environment. The apparatus includes a domain unit including a plurality of domains, each having one or more device drivers; a system resource unit forming hardware of the system; a direct memory access (DMA) driver; and a control unit including an access control module which controls the access of the domain unit to the system resource unit in the virtualized environment.