Debug Port Access Control via Trusted Execution Environment
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Solution Overview
Problem
Current solutions for securing debug ports on memory devices either disable them entirely or remove debug capabilities after manufacturing, failing to provide secure and remote access control.
Innovation Solution
Implementing a cryptographic key management system that uses a trusted execution environment (TEE) to control access to debug ports through cryptographic keys, allowing for secure and remote enabling or disabling of debug ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If debug ports are disabled entirely prior to release from manufacturing, then security is improved, but debug capability is lost
Solution Approach 1:
The debug port access control is made dynamic through cryptographic key validation. The TEE verifies cryptographic signatures on debug commands, allowing the system to transition between secured and debuggable states based on valid authentication, rather than being statically disabled
Solution Approach 2:
A cryptographic key management system acting as an intermediary is introduced between the debug port and external access attempts. The TEE validates cryptographic signatures from authorized parties, serving as a mediator that permits legitimate debug access while blocking unauthorized access
2Reliability
If debug access is disabled in the kernel, then security is improved, but remote debugging capability is removed
Solution Approach 1:
Kernel debug access control is transformed from a static disabled state to a dynamic authenticated state. The TEE validates cryptographic signatures on debug commands, enabling remote debugging when proper authentication is presented while maintaining security against unauthorized access
Solution Approach 2:
The access control parameter for the debug port is changed from a simple enabled/disabled flag to a cryptographic authentication mechanism. This allows the system to maintain security while permitting remote debugging operations when valid cryptographic credentials are provided
Data Source
AI summary
In some aspects, the techniques described herein relate to a device including: a debug port; a trusted execution environment (TEE), the TEE storing a public key; and a controller, the controller configured to: receive a command to access the debug port, the command including a signature generated using a private key corresponding to the public key; provide the command to the TEE, wherein the TEE validates the command by validating the signature using the public key to obtain a validation result; and modify access to the debug port based on the validation result.