TrustZone Sandbox for Shared Library Isolation
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Solution Overview
Problem
Existing methods for isolating shared libraries in mobile devices are inadequate as they either require modification of Android frameworks or apps, or they fail to prevent malicious libraries from leaking user privacy, and moving applications into TrustZone incurs significant performance costs and security risks.
Innovation Solution
A TrustZone-based security isolation system that dynamically creates a sandbox in the normal world, intercepts system-calling information, redirects library functions, and sets up library authority using a sandbox creator, library controller, and interceptor, allowing for secure operation without modifying memory address spaces or altering the secure world.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If applications are moved into TrustZone for isolation, then security is improved, but performance costs increase significantly
Solution Approach 1:
The patent segments the isolation mechanism by creating a sandbox environment that isolates library execution from the main application memory space. The sandbox is implemented as a separate memory region with its own execution context, allowing secure isolation without requiring the entire application to be moved into TrustZone, thus maintaining performance while improving security.
Solution Approach 2:
The patent introduces a sandbox creator and library controller as intermediary components that manage the isolation between libraries and applications. These intermediaries control memory access and execution rights, enabling secure library execution without direct TrustZone involvement, thereby reducing performance overhead while maintaining security isolation.
2Reliability
If process-based isolation is used to separate libraries and applications, then security is improved, but device complexity increases due to framework modifications
Solution Approach 1:
The patent creates a sandbox that copies the essential isolation properties of process-based separation without actually creating separate processes. The sandbox is implemented as a memory region with controlled access rights, replicating the security benefits of process isolation while avoiding the complexity of inter-process communication and framework modifications.
Solution Approach 2:
The patent changes the isolation parameter from process-level separation to memory space separation. By controlling memory access rights and creating isolated memory regions for library execution, the patent achieves security isolation without modifying Android frameworks or application structures, thereby reducing device complexity.
3Ease of operation
If application virtualization sandboxes are used for library isolation, then authority control is improved, but privacy protection fails because entire applications are isolated
Solution Approach 1:
The patent applies local quality isolation by creating a sandbox that isolates only the library execution environment, not the entire application. The sandbox provides fine-grained authority control specifically for library functions, allowing applications to maintain their full functionality while libraries are isolated in the sandbox memory region, thus protecting privacy without over-isolating.
Data Source
AI summary
The present invention provides a TrustZone-based security isolation system for shared library, the system at least comprising: a sandbox creator, a library controller, and an interceptor, the sandbox creator, in a normal world, dynamically creating a sandbox isolated from a Rich OS, the interceptor, intercepting corresponding system-calling information and/or Android framework APIs by means of inter-process stack inspection, the library controller, performing analysis based on the intercepted system-calling information and/or Android framework APIs, redirecting a library function to the sandbox, and switching calling states of the library function in the sandbox as well as setting up a library authority. The present invention has good versatility, low cost and high security. It realizes isolation of the library without increasing the trusted bases in the Secure World of the TrustZone, effectively reducing the risk of being attacked.