pdf.js/test/fuzz/README.md
manunio 8bb8070116 fuzz: initial integration
- Adds initial fuzz_target for image decoders.
  - Adds jazzer.js as dev-dependency.
  - Adds a .eslintrc rule to ignore import/no-unresolved error.
2023-12-03 18:52:48 +05:30

1.5 KiB

Fuzz Testing

Fuzz testing is:

An automated software testing technique that involves providing invalid, unexpected, or random data as inputs to a program.

We use coverage guided fuzz testing to automatically discover bugs in PDF.js.

This fuzz/ directory contains the configuration and the fuzz tests for PDF.js. To generate and run fuzz tests, we use the Jazzer.js library.

Running a fuzzer

This directory contains fuzzers like for example jpeg_image.fuzz. You can run it with:

Generate image decoders:

$ gulp image_decoders

Run fuzz target:

$ npx jazzer fuzz/jpeg_image.fuzz --sync

You should see output that looks something like this:

#2      INITED exec/s: 0 rss: 128Mb
#65536  pulse  corp: 1/1b lim: 652 exec/s: 32768 rss: 140Mb
#131072 pulse  corp: 1/1b lim: 1300 exec/s: 32768 rss: 140Mb
#262144 pulse  corp: 1/1b lim: 2611 exec/s: 32768 rss: 140Mb
#524288 pulse  corp: 1/1b lim: 4096 exec/s: 30840 rss: 140Mb
#1048576        pulse  corp: 1/1b lim: 4096 exec/s: 29959 rss: 140Mb
#2097152        pulse  corp: 1/1b lim: 4096 exec/s: 29537 rss: 140Mb

It will continue to generate random inputs forever, until it finds a bug or is terminated. The testcases for bugs it finds can be seen in the form of crash-* or timeout-* at the place from where command is run. You can rerun the fuzzer on a single input by passing it on the command line npx jazzer fuzz/jpeg_image.fuzz /path/to/testcase.