Awesome

Differential fuzzing for leveldb and rocksdb.

One way to go about things right now (until background threads in rocksdb are handled) is to use AFL, fuzz leveldb, then run the tests on the two databases together. This is pretty simple, just

1. install DeepState. The easiest way to do this is probably the DeepState docker.

2. build both databases using afl-clang as your compiler, to get instrumentation (in fact, for now, you can skip this for RocksDB, just build it)

3. build the fuzzers, and fuzz leveldb like, e.g., this:

~/afl/afl-fuzz -i <sometest> -o <output_dir> -- ./TestLevelDB --input_test_file @@ --exit_on_fail

You can also go for libFuzzer based testing:

1. install DeepState with BUILD_LIBFUZZER=TRUE

2. install leveldb, after editing its CMakeLists.txt to add -fsanitize=integer,undefined,address,fuzzer-no-link

editing the CMakeLists.txt thus:

@@ -40,6 +40,7 @@ include(CheckCXXSourceCompiles)
 # -Werror is necessary because unknown attributes only generate warnings.
 set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
 list(APPEND CMAKE_REQUIRED_FLAGS -Werror -Wthread-safety)
+list(APPEND CMAKE_REQUIRED_FLAGS -fsanitize=fuzzer-no-link,integer,address,undefined)
 check_cxx_source_compiles("
 struct __attribute__((lockable)) Lock {
 void Acquire() __attribute__((exclusive_lock_function()));

may work

Make sure to use a clang >= 6.0 to compile!

3. install rocksdb, after editing its Makefile to add -fsanitize=integer,undefined,address,fuzzer-no-link:

@@ -232,6 +232,11 @@ ifneq ($(filter -DROCKSDB_LITE,$(OPT)),)
        LUA_PATH =
 endif
 
+DISABLE_JEMALLOC=1
+EXEC_LDFLAGS += -fsanitize=address,integer,undefined,fuzzer-no-link
+PLATFORM_CCFLAGS += -fsanitize=address,integer,undefined,fuzzer-no-link
+PLATFORM_CXXFLAGS += -fsanitize=address,integer,undefined,fuzzer-no-link
+
 # ASAN doesn't work well with jemalloc. If we're compiling with ASAN, we should use regular malloc.
 ifdef COMPILE_WITH_ASAN
        DISABLE_JEMALLOC=1

Make sure to use a clang >= 6.0 to compile!

4. edit this repo's Makefile to link to deepstate_LF or deepstate_AFL to build libfuzzer/afl fuzzers.

Using a ramdisk for the databases is STRONGLY recommended, unless you want to both fuzz slowly and burn out your SSD.

5. make

DiffTestDBs and DiffTestDBs_LF are the primary fuzzers. TestLevelDB just runs leveldb, without differential testing with RocksDB. Tests from TestLevelDB run in DiffTestDBs. If you have trouble building the databases with instrumentation, in fact, you can just build them exactly as you normally would for release, and then use Eclipser to fuzz TestLevelDB. Unfortunately, some issue currently prevents Eclipser from fuzzing rocksdb.