harfbuzz

History

Ebrahim Byagowi 11d583a9ea [aat] Consume glyph insertion from buffer's max_ops (#2223 ) Glyph insertion is an expensive operation and we like to have it limited based on buffer's input size which is handled by buffer's max_ops. clusterfuzz-testcase-minimized-harfbuzz_fuzzer-5754958982021120: Before the change: 0.67s user 0.00s system 99% cpu 0.674 total After the change: 0.02s user 0.00s system 98% cpu 0.024 total Which takes much longer on valgrind and tsan bots.		2020-07-13 18:53:06 -07:00
..
fonts	[aat] Consume glyph insertion from buffer's max_ops (#2223 )	2020-07-13 18:53:06 -07:00
sets	[fuzz] minor, move two fuzzer cases to their correct place	2020-02-12 19:17:18 +03:30
hb-draw-fuzzer.cc	[tests] Enable more gid misc calls on draw fuzzer	2020-05-21 07:00:40 +04:30
hb-fuzzer.hh	[fuzzer] Separate main() into a new file	2016-12-20 20:50:38 -06:00
hb-set-fuzzer.cc	Minor, disable strict-aliasing warning in set fuzzer	2020-07-05 10:49:10 +04:30
hb-shape-fuzzer.cc	[fuzzer] Make some use for test_font API calls	2020-06-20 22:06:11 +04:30
hb-subset-fuzzer.cc	[fuzz] Don't fail when blob is empty	2019-07-11 14:31:55 +04:30
main.cc	[fuzz] minor don't abort main.cc when the file was empty or not found	2020-02-26 16:15:17 +03:30
Makefile.am	Remove cmake testing and add meson build bot	2020-03-11 20:15:10 +03:30
meson.build	[meson] Raise timeout value of subset fuzzer testcases	2020-07-12 23:05:11 +04:30
README	Move all references of old url to the new address (#622 )	2017-11-20 14:49:22 -05:00
run-draw-fuzzer-tests.py	[ci] migrate to meson	2020-07-08 19:18:31 +04:30
run-shape-fuzzer-tests.py	[ci] migrate to meson	2020-07-08 19:18:31 +04:30
run-subset-fuzzer-tests.py	[ci] migrate to meson	2020-07-08 19:18:31 +04:30

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.
    See FUZZING_CPPFLAGS in harfbuzz/src/Makefile.am for the list.
  - 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/harfbuzz/harfbuzz/issues/139