WADIFF: A Differential Testing Framework for WebAssembly Runtimes

WebAssembly (Wasm) runtime provides a virtual machine that can execute the WebAssembly modules and is widely used in different areas (e.g., browsers, edge computing, blockchain). Thus, the precision and reliability of the WebAssembly runtime are important and deserve our attention. To ensure the correctness and detect potential bugs in WebAssembly runtimes, we propose WADIFF, a differential testing framework, which consists of a sufficient test case generator and a deterministic differential testing engine. To evaluate the effectiveness of WADIFF, we apply it to seven popular WebAssembly runtimes and found 417 inconsistent instructions due to bugs and different implementations in the runtimes. Furthermore, we identify 21 bugs from 7 WebAssembly runtimes, and 8 of them are confirmed by their developers.