f1064c1b0d
9220a0fdd0f3dc2c8dd7cbeefac7d11106451b51 tests: Add one specialized ProcessMessage(...) fuzzing binary per message type for optimal results when using coverage-guided fuzzing (practicalswift)
fd1dae10b4a549ba9292d837235d59bd9eebbed3 tests: Add fuzzing harness for ProcessMessage(...) (practicalswift)
Pull request description:
Add fuzzing harness for `ProcessMessage(...)`. Enables high-level fuzzing of the P2P layer.
All code paths reachable from this fuzzer can be assumed to be reachable for an untrusted peer.
Seeded from thin air (an empty corpus) this fuzzer reaches roughly 20 000 lines of code.
To test this PR:
```
$ make distclean
$ ./autogen.sh
$ CC=clang CXX=clang++ ./configure --enable-fuzz \
--with-sanitizers=address,fuzzer,undefined
$ make
$ src/test/fuzz/process_message
…
```
Worth noting about this fuzzing harness:
* To achieve a reasonable number of executions per seconds the state of the fuzzer is unfortunately not entirely reset between `test_one_input` calls. The set-up (`FuzzingSetup` ctor) and tear-down (`~FuzzingSetup`) work is simply too costly to be run on every iteration. There is a trade-off to handle here between a.) achieving high executions/second and b.) giving the fuzzer a totally blank slate for each call. Please let me know if you have any suggestion on how to improve this situation while maintaining >1000 executions/second.
* To achieve optimal results when using coverage-guided fuzzing I've chosen to create one specialised fuzzing binary per message type (`process_message_addr`, `process_message_block`, `process_message_blocktxn `, etc.) and one general fuzzing binary (`process_message`) which handles all messages types. The latter general fuzzer can be seeded with inputs generated by the former specialised fuzzers.
Happy fuzzing friends!
ACKs for top commit:
MarcoFalke:
ACK 9220a0fdd0 🏊
Tree-SHA512: c314ef12b0db17b53cbf3abfb9ecc10ce420fb45b17c1db0b34cabe7c30e453947b3ae462020b0c9f30e2c67a7ef1df68826238687dc2479cd816f0addb530e5
Unit tests
The sources in this directory are unit test cases. Boost includes a unit testing framework, and since Bitcoin Core already uses Boost, it makes sense to simply use this framework rather than require developers to configure some other framework (we want as few impediments to creating unit tests as possible).
The build system is set up to compile an executable called test_bitcoin
that runs all of the unit tests. The main source file for the test library is found in
util/setup_common.cpp.
Compiling/running unit tests
Unit tests will be automatically compiled if dependencies were met in ./configure
and tests weren't explicitly disabled.
After configuring, they can be run with make check.
To run the bitcoind tests manually, launch src/test/test_bitcoin. To recompile
after a test file was modified, run make and then run the test again. If you
modify a non-test file, use make -C src/test to recompile only what's needed
to run the bitcoind tests.
To add more bitcoind tests, add BOOST_AUTO_TEST_CASE functions to the existing
.cpp files in the test/ directory or add new .cpp files that
implement new BOOST_AUTO_TEST_SUITE sections.
To run the bitcoin-qt tests manually, launch src/qt/test/test_bitcoin-qt
To add more bitcoin-qt tests, add them to the src/qt/test/ directory and
the src/qt/test/test_main.cpp file.
Running individual tests
test_bitcoin has some built-in command-line arguments; for example, to run just the getarg_tests verbosely:
test_bitcoin --log_level=all --run_test=getarg_tests
... or to run just the doubledash test:
test_bitcoin --run_test=getarg_tests/doubledash
Run test_bitcoin --help for the full list.
Adding test cases
To add a new unit test file to our test suite you need
to add the file to src/Makefile.test.include. The pattern is to create
one test file for each class or source file for which you want to create
unit tests. The file naming convention is <source_filename>_tests.cpp
and such files should wrap their tests in a test suite
called <source_filename>_tests. For an example of this pattern,
see uint256_tests.cpp.
Logging and debugging in unit tests
To write to logs from unit tests you need to use specific message methods
provided by Boost. The simplest is BOOST_TEST_MESSAGE.
For debugging you can launch the test_bitcoin executable with gdbor lldb and
start debugging, just like you would with bitcoind:
gdb src/test/test_bitcoin