Re-order Buffer Timing Randomization for Security
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Solution Overview
Problem
Existing computer processor architectures with out-of-order execution are vulnerable to timing-based security attacks, such as Meltdown and Spectre, which exploit predictable timing patterns in re-order buffers to leak privileged information.
Innovation Solution
Introducing randomness in the timing pattern of re-order buffers by dynamically adjusting their capacity based on random number generator outputs, either periodically or at random intervals, to disrupt the predictability of data timing and prevent attackers from exploiting timing-based attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If out-of-order execution is implemented to improve processor utilization and execution speed, then processing efficiency is improved, but security vulnerability increases due to predictable timing patterns in re-order buffers
Solution Approach 1:
The re-order buffer capacity is made dynamic rather than fixed. The buffer capacity is adjusted based on randomly selected values from a range, causing the timing patterns of instruction execution to vary unpredictably. This dynamic adjustment maintains the out-of-order execution functionality while preventing attackers from exploiting consistent timing patterns to leak privileged information.
2Device complexity
If fixed re-order buffer capacity is used to simplify processor design, then device complexity is reduced, but timing predictability increases making the system vulnerable to security attacks
Solution Approach 1:
The re-order buffer capacity parameter is changed from a fixed value to a variable that is randomly selected from a range. This parameter change introduces unpredictability into the system's timing behavior, preventing security attacks that rely on predictable timing patterns, while adding minimal complexity to the processor design.
Data Source
AI summary
Methods, systems, and apparatuses related to re-order buffers and for protection from timing-based security attacks are described. A processor may have functional units configured to execute instructions out of order, a re-order buffer configured to buffer the execution results of instructions for output in order, and a controller configured to randomize data timing in the re-order buffer. For example, the controller can make random adjustments to the capacity of the re-order buffer in buffering and/or sorting execution results and thus randomize data timing in the re-order buffer.