diff --git a/fuzz/README.md b/fuzz/README.md new file mode 100644 index 000000000..eeb43ebd5 --- /dev/null +++ b/fuzz/README.md @@ -0,0 +1,38 @@ +This directory contains the fuzz tests for wasmer. To fuzz, we use the `cargo-fuzz` package. + +## Installation + +You may need to install the `cargo-fuzz` package to get the `cargo fuzz` subcommand. Use + +```sh +$ cargo install cargo-fuzz +``` + +`cargo-fuzz` is documented in the [Rust Fuzz Book](https://rust-fuzz.github.io/book/cargo-fuzz.html). + +## Running a fuzzer + +Once `cargo-fuzz` is installed, you can run the `simple_instantiate` fuzzer with +```sh +cargo fuzz run simple_instantiate +``` + +You should see output that looks something like this: + +``` +INFO: Seed: 3276026494 +INFO: 8 files found in wasmer/fuzz/corpus/simple_instantiate +INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 4096 bytes +INFO: seed corpus: files: 8 min: 1b max: 1b total: 8b rss: 133Mb +#9 INITED ft: 3 corp: 3/3b lim: 4 exec/s: 0 rss: 142Mb +#23 NEW ft: 4 corp: 4/5b lim: 4 exec/s: 0 rss: 142Mb L: 2/2 MS: 4 ChangeByte-InsertByte-ShuffleBytes-ChangeBit- +#25 NEW ft: 5 corp: 5/6b lim: 4 exec/s: 0 rss: 142Mb L: 1/2 MS: 2 ChangeBinInt-ChangeBit- +#27 NEW ft: 6 corp: 6/9b lim: 4 exec/s: 0 rss: 142Mb L: 3/3 MS: 2 InsertByte-ChangeByte- +#190 REDUCE ft: 6 corp: 6/7b lim: 4 exec/s: 0 rss: 142Mb L: 1/2 MS: 3 ChangeBit-EraseBytes-CrossOver- +#205 REDUCE ft: 7 corp: 7/11b lim: 4 exec/s: 0 rss: 142Mb L: 4/4 MS: 5 ShuffleBytes-CrossOver-InsertByte-ChangeBinInt-CrossOver- +``` +It will continue to generate random inputs forever, until it finds a bug or is terminated. The testcases for bugs it finds go into `fuzz/artifacts/simple_instantiate` and you can rerun the fuzzer on a single input by passing it on the command line `cargo fuzz run simple_instantiate my_testcase.wasm`. + +## Trophy case + +- [x] https://github.com/wasmerio/wasmer/issues/558