README.fuzzing.md

Fuzzing libmaxminddb

These tests are only meant to be run on GNU/Linux.

Build maxminddb fuzzer using libFuzzer.

Export flags for fuzzing.

Note that in CFLAGS and CXXFLAGS, any type of sanitizers can be added.

• AddressSanitizer, ThreadSanitizer, MemorySanitizer, UndefinedBehaviorSanitizer, LeakSanitizer.

$ export CC=clang
$ export CXX=clang++
$ export CFLAGS="-g -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address,undefined -fsanitize=fuzzer-no-link"
$ export CXXFLAGS="-g -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address,undefined -fsanitize=fuzzer-no-link"
$ export LIB_FUZZING_ENGINE="-fsanitize=fuzzer"

Build maxminddb for fuzzing.

$ mkdir -p build && cd build
$ cmake -DBUILD_FUZZING=ON ../.
$ cmake --build . -j$(nproc)

Running fuzzer.

$ mkdir -p fuzz_mmdb_seed fuzz_mmdb_seed_corpus
$ find ../t/maxmind-db/test-data/ -type f -size -4k -exec cp {} ./fuzz_mmdb_seed_corpus/ \;
$ ./t/fuzz_mmdb fuzz_mmdb_seed/ fuzz_mmdb_seed_corpus/

Here is more information about LibFuzzer.