Rust Target-OS Device Management With Checked Privileged Interfaces
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Solution Overview
Problem
The use of the unsafe keyword in Rust-based operating systems poses significant security and stability risks due to potential misuse by programmers, leading to an enlarged trusted base and increased system instability.
Innovation Solution
Implement a device management architecture that separates privileged and non-privileged code, where device drivers operate at a non-privilege level without using the unsafe keyword, while the device management module at the privilege level includes the unsafe code and performs security checks, ensuring safe execution of operations related to peripheral device management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the unsafe keyword is used to enable high-performance operations and special functions in Rust operating systems, then programming flexibility and performance are improved, but system stability and security deteriorate due to potential misuse and enlarged trusted base
Solution Approach 1:
The patent divides the operating system code into two distinct segments: privileged code (kernel mode) that can use the unsafe keyword for high-performance operations, and non-privileged code (user mode) that cannot use unsafe keyword. This segmentation isolates the risk of unsafe operations to a limited scope while maintaining flexibility where needed. The interface module acts as a boundary between these segments, allowing controlled interaction.
Solution Approach 2:
The patent introduces an interface module as an intermediary between device drivers (non-privileged) and the kernel code (privileged). This intermediary layer performs security checks and validates operations before allowing access to privileged resources, preventing direct misuse of unsafe keyword by user-mode code while maintaining necessary functionality.
2Speed
If the unsafe keyword is used to bypass mandatory security checks for high-performance scenarios, then execution speed is improved, but security and trust burden increase due to programmer responsibility
Solution Approach 1:
The patent applies different quality characteristics to different code regions: the privileged code region allows unsafe keyword usage for high-performance operations, while the non-privileged code region prohibits unsafe keyword usage for security. This local differentiation enables optimization where needed while maintaining security where critical.
Solution Approach 2:
The interface module performs preliminary security checks before allowing any operation to proceed to the privileged code level. This preliminary validation ensures that only safe and authorized operations reach the unsafe code regions, reducing the security burden on individual programmers while maintaining performance benefits.
3Ease of operation
If device drivers are written without unsafe keyword restrictions, then ease of programming is improved, but system security deteriorates due to potential undefined behavior
Solution Approach 1:
The interface module serves as a mediator that simplifies programming for device drivers while maintaining security. It provides a safe abstraction layer that translates high-level driver requests into validated low-level operations, eliminating the need for drivers to directly handle unsafe operations while preserving ease of use.
Solution Approach 2:
The system provides self-service security through the interface module's automatic security checks. Instead of requiring programmers to manually ensure safety, the interface module autonomously validates operations and enforces security policies, making secure programming accessible to all users without additional burden.
Data Source
AI summary
Embodiments of this specification provide a method and an apparatus for device management in a target operating system. The target operating system is written in a Rust language. The Rust language includes an unsafe keyword. The method relates to a device driver of a peripheral device and a device management module. The method includes: receiving, by an interface module in the device management module, a target request sent by the device driver, where the target request is an operation request related to interrupt configuration or access of the peripheral device, and the interface module includes no code segment using the unsafe keyword; performing, by the interface module, a security check related to the operation request; and after the security check succeeds, performing, by a kernel code module in the device management module, a target operation corresponding to the operation request by using code that includes the unsafe keyword.