PCIe Downstream Port VDM Security Verification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Information handling systems face the risk of malicious operations from unknown PCIe devices that can exploit PCIe Vendor-Defined-Messages (VDM) communications, potentially compromising other devices within the system.

Innovation Solution

The implementation of a PCIe downstream port that blocks PCIe VDMs by default and allows them only after verifying the digital signature of connected endpoints, ensuring secure communication by maintaining a configuration bit to control VDM access and utilizing Management Component Transport Protocol (MCTP) for secure network connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PCIe VDMs are allowed by default, then device communication flexibility is improved, but system security deteriorates due to potential malicious operations from unknown devices

Engineering Contradiction:

Improvedevice communication flexibilityVSAvoidsystem security risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary verification of the PCIe endpoint's digital signature before allowing VDM communications. The downstream port checks the signature in advance and only permits VDMs if the signature is valid, preventing malicious devices from exploiting VDM capabilities without compromising legitimate device functionality.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If PCIe VDMs are blocked by default, then system security is improved, but device communication capability deteriorates

Engineering Contradiction:

Improvesystem securityVSAvoiddevice communication capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system implements a feedback mechanism where the downstream port verifies the digital signature of the PCIe endpoint and adjusts its behavior accordingly. If the signature is valid, the port switches from blocking to allowing VDMs, providing feedback-based control that balances security and functionality.

Inventive Principle:

Principle #23Feedback

3Reliability

If digital signature verification is implemented, then security against malicious devices is improved, but system complexity increases

Engineering Contradiction:

Improvesecurity against malicious devicesVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The downstream port acts as an intermediary between the PCIe endpoint and the rest of the system. It handles the digital signature verification and VDM control logic centrally, isolating the complexity from the broader system while maintaining security. The intermediary verifies signatures and makes decisions about VDM permission without requiring widespread system changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11017071B2Apparatus and method to protect an information handling system against other devices

Publication Date: 2021.05.25 DELL PROD LP

AI summary

An information handling system includes a processor, a peripheral component interconnect express (PCIe) endpoint, and a PCIe downstream port. The PCIe downstream port blocks PCIe vendor-defined messages (VDMs) from the PCIe endpoint as a default mode, changes to a second mode in response to the PCIe endpoint being verified, and allows PCIe VDMs from the PCIe endpoint while in the second mode.