Watchdog Timer Boot Tampering Detection Reboots
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Solution Overview
Problem
The prolonged boot time of information processing apparatuses due to tampering detection at boot time leads to unnecessary reboots, which can be detrimental to the operation of devices like printing and reading devices.
Innovation Solution
An information processing apparatus equipped with a watchdog timer (WDT) that stops counting and prevents rebooting when tampering detection is enabled, allowing the device to complete the boot process even if tampering is detected, by setting a longer initial count value or resetting the count based on the tampering detection function settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tampering detection is performed at boot time, then security is improved, but boot time is prolonged
Solution Approach 1:
The watchdog timer is pre-configured with an initial count value that is specifically set to accommodate the time required for tampering detection. This preliminary setup ensures that the timer does not trigger a reboot during the detection process, allowing security checks to complete without interruption.
Solution Approach 2:
The system dynamically adjusts the watchdog timer behavior based on the execution state of boot software. When boot software is detected to be executing, the watchdog timer is configured to wait until completion before triggering a reboot, rather than using a fixed timeout period.
2Reliability
If watchdog timer is used to monitor boot completion, then system reliability is improved, but unnecessary reboots occur when tampering detection is enabled
Solution Approach 1:
The system implements feedback mechanisms where the execution state of boot software is continuously monitored and fed back to the watchdog timer control logic. This feedback allows the system to distinguish between legitimate prolonged boot times due to security checks and actual boot failures, preventing false reboot triggers.
Solution Approach 2:
The patent introduces an intermediary control mechanism that sits between the watchdog timer and the reboot function. This intermediary evaluates the current system state (specifically whether tampering detection is active and whether boot software is executing) before allowing the watchdog timer to trigger a reboot, thus preventing unnecessary reboots.
Data Source
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AI summary
An information processing apparatus (1) includes detection means (101, 121) configured to detect tampering with at least one of a plurality of software components to be executed in accordance with a boot instruction, storage means (120, 901) configured to store information for enabling or disabling a function of detecting the tampering, and reboot means (109) configured to reboot the information processing apparatus on the basis of the information stored in the storage means and on the basis of a time that elapses after receipt of the boot instruction.