CAN Clock Control for Secure Transmit Buffer Handling
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Solution Overview
Problem
Modern vehicle networks, particularly those using the Controller Area Network (CAN) protocol, are vulnerable to attacks where adversaries can inject non-compliant messages, exploiting software interfaces to disrupt communication, which existing defense mechanisms are ineffective against.
Innovation Solution
Implementing software and hardware-based control structures that manage the clock enable signal and transmit buffer status to prevent unauthorized clock disabling, ensuring secure communication by inhibiting clock stop requests when the transmit buffer is not empty and resetting the CAN controller to a safe state if the clock is disabled for an extended duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the clock is disabled to save power during idle periods, then energy consumption is reduced, but communication robustness deteriorates because data in the transmit buffer may be lost
Solution Approach 1:
The system performs a preliminary check of the transmit buffer status before disabling the clock. If the buffer is not empty, the clock disable operation is blocked, preventing data loss. This preliminary action ensures that power-saving operations do not compromise communication reliability.
Solution Approach 2:
The system continuously monitors the transmit buffer status and uses this feedback to control clock disabling. The buffer status signal feeds back to the clock control logic, dynamically enabling or disabling the clock based on real-time conditions, thus balancing power consumption and communication robustness.
2Ease of operation
If software interfaces allow flexible clock control for power management, then ease of operation is improved, but security deteriorates because adversaries can inject malicious messages by exploiting these interfaces
Solution Approach 1:
The transmit buffer status signal acts as an intermediary between the software power management interface and the clock control hardware. This intermediary layer validates power management requests against communication state, allowing legitimate power savings while blocking malicious operations that would compromise message integrity.
Solution Approach 2:
The system applies preliminary anti-action by checking buffer status before allowing clock disable operations. This preemptive measure counteracts potential malicious message injection attempts by preventing the clock from being disabled during critical transmission periods, thus neutralizing the attack vector before it can execute.
3Reliability
If the clock remains enabled continuously to ensure communication robustness, then communication reliability is maintained, but energy consumption increases
Solution Approach 1:
The clock enable/disable state transitions dynamically based on transmit buffer conditions. Rather than a static always-on or always-off configuration, the system adapts the clock state in real-time, enabling it when data is pending and disabling it when the buffer is empty, thus optimizing the balance between reliability and power consumption.
Data Source
AI summary
A computer system for performing control of an electronic control unit (ECU) having a processor for executing computer-readable instructions and a memory for maintaining the computer-executable instructions, the computer-executable instructions when executed by the processor perform the following functions by a processor. The functions include configuring a communication controller to while operating in a secure mode, transiting to an unsecure mode, executing a program in the unsecure mode that utilizes the communication controller; and in response to detecting a clock off request while a transmit buffer of the communication controller is not empty, inhibiting the clock off request until the transmit buffer is empty.