Composable Actor Operating System for Attack Surface Reduction
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Solution Overview
Problem
Traditional operating systems have a large 'attack surface' with many vulnerable points, making them difficult to prove safe and stable, and their complexity complicates ensuring security and real-time functionality, especially in critical applications like automated navigation systems.
Innovation Solution
The operating system is designed using a capability-based approach with actors and channels, where each actor has a controlled interface and communicates through channels, allowing for the creation of composed actors that maintain stability and safety, reducing the attack surface and preventing privilege leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional operating system with a large code base and many programming interfaces is used, then the system has high functionality and versatility, but the attack surface increases and security vulnerabilities multiply
Solution Approach 1:
The operating system is divided into isolated actors that communicate through controlled channels. Each actor is a self-contained unit with a specific function, preventing attackers from exploiting the entire system through a single vulnerability. The segmentation creates multiple isolation boundaries that limit the spread of attacks.
Solution Approach 2:
Channels serve as intermediary components between actors, providing controlled and verified communication paths. The channel mechanism ensures that interactions between actors are authenticated and authorized, preventing unauthorized access even when actors have diverse functionality.
2Adaptability or versatility
If most of the operating system executes in privileged mode to access sensitive resources, then the system has high functionality, but the risk of privilege leaks and system compromise increases
Solution Approach 1:
Different actors are assigned different privilege levels based on their specific needs. Instead of the entire system running in privileged mode, only the minimal necessary portions execute with elevated privileges. This localized privilege assignment reduces the attack surface while maintaining required functionality.
Solution Approach 2:
The system separates privileged and unprivileged operations into distinct actors. Critical resource access is isolated to specific actors that require privileged mode, while other actors run in user mode. This segmentation limits the impact of privilege leaks to isolated components.
3Adaptability or versatility
If the operating system has a large code base with frequently updated modules, then the system has high adaptability, but it becomes difficult to prove stability and safety
Solution Approach 1:
The actor model enables independent verification of individual components. Each actor can be analyzed and proven safe in isolation, and these proofs compose to guarantee the safety of the entire system. This modular approach makes formal verification tractable even as the system grows and evolves.
Solution Approach 2:
The system maintains continuous safety guarantees through the compositional nature of actor proofs. As actors are added or updated, their safety proofs are combined with existing proofs to maintain overall system safety, allowing continuous adaptation without losing stability guarantees.
4Object-affected harmful factors
If actors are tightly isolated through controlled channels, then the attack surface is reduced, but the complexity of assembling and managing composed actors increases
Solution Approach 1:
The composed actor mechanism allows multiple actors to be merged into a single logical unit that presents a unified interface to the outside world. This merging simplifies the management of complex actor networks by providing higher-level abstractions while maintaining the security benefits of underlying isolation.
Solution Approach 2:
The channel mechanism serves multiple functions: it provides communication between actors, enforces security policies, manages privilege separation, and enables composition of actors. This universal mechanism reduces the need for separate complexity-handling infrastructure.
Data Source
AI summary
In an embodiment, an operating system for a computer system is built on a set of capabilities. Each capability includes at least one pointer to a function that implements the capability. One or more actors are defined which use one or more of the capabilities, and which may be connected to other actors for communication through channels. The channels may be created and maintained by a channel actor. In an embodiment, one or more actors may be assembled to create a composed actor. The actors within the composed actor still communicate over the channels defined between the internal actors, but may pass channel identifiers for actors outside the composed actor, so that the actors within the composed actor communicate with the outside actors as if they were one single actor. Arbitrarily complex actors may be formed in this fashion, while still maintaining the stability and safety of the initial actors.