harfbuzz/test/fuzzing
Behdad Esfahbod a6d7668a95 [fuzzing] Cap max buffer len at 128 2015-11-06 09:46:54 -08:00
..
Makefile.am [fuzzing] Cap max buffer len at 128 2015-11-06 09:46:54 -08:00
README [fuzzing] Add build system 2015-11-05 23:08:50 -08:00
hb-fuzzer.cc [fuzzing] Add build system 2015-11-05 23:08:50 -08:00

README

In order to build the fuzzer one needs to build HarfBuzz and
harfbuzz/test/fuzzing/hb-fuzzer.cc with:
  - Using the most recent Clang
  - With -fsanitize=address (or =undefined, or a combination)
  - With -fsanitize-coverage=edge[,8bit-counters,trace-cmp]
  - With various defines that limit worst case exponential behavior:
    * -DHB_MAX_NESTING_LEVEL=3
    * -DHB_SANITIZE_MAX_EDITS=3
    * See Makefile.am for full list of flags
  - link against libFuzzer

To run the fuzzer one needs to first obtain a test corpus as a directory
containing interesting fonts.  A good starting point is inside
harfbuzz/test/shaping/fonts/fonts/.
Then, run the fuzzer like this:
   ./hb-fuzzer -max_len=2048 CORPUS_DIR
Where max_len specifies the maximal length of font files to handle.
The smaller the faster.

For more details consult the following locations:
  - http://llvm.org/docs/LibFuzzer.html or
  - https://github.com/google/libfuzzer-bot/tree/master/harfbuzz
  - https://github.com/behdad/harfbuzz/issues/139