Processor Debug Access Control via Credential Verification
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Solution Overview
Problem
Conventional processor debug features pose a security risk as they can be used to access sensitive information and affect processor operation, lacking effective access control mechanisms.
Innovation Solution
The technology introduces a debug control circuitry that allows builders to configure access to processor debug features, preventing suppliers from accessing certain features and restricting access to only authorized debuggers, using credential stores, security processors, and debug tokens to enforce access restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If debug features are made accessible for debugging purposes, then ease of operation is improved, but security is worsened due to potential unauthorized access to sensitive information
Solution Approach 1:
The patent segments access control by creating distinct credential stores for different entities (supplier, builder, consumer) and implementing role-based access control. Each entity type has specific credentials that grant particular levels of access to debug features, thereby enabling controlled accessibility while maintaining security through differentiated permission levels.
Solution Approach 2:
The patent introduces an intermediary credential verification mechanism that mediates between debug feature requests and actual access. The debug control circuitry acts as an intermediary that validates credentials from suppliers, builders, or consumers before granting access to debug features, thus enabling secure access control without completely blocking debugging functionality.
2Object-affected harmful factors
If access control mechanisms are implemented for debug features, then security is improved, but device complexity is worsened due to additional control circuitry and credential management
Solution Approach 1:
The patent implements a universal credential verification framework that handles multiple entity types (suppliers, builders, consumers) through a common control circuitry architecture. The debug control circuitry can verify different credential types from different entities using the same verification logic, thereby reducing overall system complexity compared to implementing separate control mechanisms for each entity type.
Solution Approach 2:
The patent enables self-service credential verification where the debug control circuitry autonomously validates credentials without requiring external authorization servers or complex management infrastructure. The credential stores contain all necessary verification information locally, allowing the system to self-manage access control decisions without adding external complexity.
Data Source
AI summary
A processor that was manufactured by a manufacturer comprises privileged debug operational circuitry, a debug restriction fuse, a credential store, a credential of the manufacturer in the credential store, and debug control circuitry. The debug restriction fuse is a one-time programmable fuse. The debug control circuitry is to automatically restrict access to the privileged debug operational circuitry, based on the debug restriction fuse. The processor may also include public debug operational circuitry, a prevent-unauthorized-debug (PUD) fuse, and an undo-PUD fuse. When the PUD fuse is set and the undo-PUD fuse is clear, the debug control circuitry may respond to an attempt by a debugger to use the public debug operational circuitry by determining whether the debugger is authorized, disallowing access if the debugger is not authorized, and allowing access if the debugger is authorized. Other embodiments are described and claimed.