Sudoku: Decomposing DRAM Address Mapping into Component Functions

TL;DR

This paper introduces Sudoku, a software tool that automatically decomposes DRAM address mappings into component functions using timing-based techniques, aiding understanding of memory behavior and security analysis.

Contribution

Sudoku is the first tool to automatically decompose full DRAM address mappings into component functions on recent processors.

Findings

Successfully decomposes mappings on Intel and AMD processors

Uses timing-based techniques leveraging refresh intervals and access latencies

Enables precise understanding of DRAM address components

Abstract

Decomposing DRAM address mappings into component-level functions is critical for understanding memory behavior and enabling precise RowHammer attacks, yet existing reverse-engineering methods fall short. We introduce novel timing-based techniques leveraging DRAM refresh intervals and consecutive access latencies to infer component-specific functions. Based on this, we present Sudoku, the first software-based tool to automatically decompose full DRAM address mappings into channel, rank, bank group, and bank functions while identifying row and column bits. We validate Sudoku's effectiveness, successfully decomposing mappings on recent Intel and AMD processors.