Recovery Image Boot Sequence Validation

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Solution Overview

Problem

Computing systems face risks when booting from outdated recovery images, which may contain security vulnerabilities, and existing methods lack effective mechanisms to mitigate these risks during the boot process.

Innovation Solution

The system detects a valid recovery image, verifies its authenticity, compares version identifiers between the image and the system's stored version, and optionally imposes a delay before executing the boot sequence from an outdated recovery image to prevent exploitation by attackers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the system boots from an outdated recovery image, then system recovery capability is maintained, but security vulnerabilities increase

Engineering Contradiction:

Improvesystem recovery capabilityVSAvoidsecurity vulnerabilities

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary validation of the recovery image by verifying the keyblock signature and comparing version identifiers before allowing the boot process to proceed. This advance checking prevents execution of potentially compromised outdated images while maintaining the ability to recover using valid images.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A delay mechanism is introduced as an intermediary between detecting the outdated recovery image and executing the boot sequence. This delay period allows time for security warnings to be presented to the user, creating a buffer that prevents automatic execution of potentially vulnerable images.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the system implements version comparison and delay mechanisms, then security against outdated images is improved, but boot process time increases

Engineering Contradiction:

Improvesecurity risk from outdated imagesVSAvoidboot process time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system applies version comparison and delay mechanisms selectively - only when an outdated recovery image is detected. If the recovery image version matches or exceeds the system version, the boot process proceeds without additional delays. This partial application minimizes time loss while maintaining security where needed.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If the system validates keyblock authenticity, then trust in recovery image is ensured, but complexity of boot process increases

Engineering Contradiction:

Improvetrust in recovery imageVSAvoidboot process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The validation process is designed to be self-contained within the existing boot infrastructure. The keyblock verification and version comparison operations are integrated into the normal boot sequence, utilizing existing cryptographic libraries and version management systems already present in the computing device.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9575840B1Recovery rollback risk reduction

Publication Date: 2017.02.21 GOOGLE LLC

AI summary

Aspects of the subject technology relate to executing a boot sequence from a recovery image. A determination of a validity of one or more keyblocks is made. A determination of a first version identifier and a second version identifier is made. A comparison of the first version identifier and the second version identifier is performed. A boot sequence from a recovery image is executed based on the comparison.