[In-Progress] Kicking off fuzz testing with libfuzzer

.circleci/config.yml

@@ -4,7 +4,7 @@ version: 2.1
 jobs:
   lint:
     docker:
-      - image: redislabsmodules/llvm-toolset:latest
+      - image: silkeh/clang:12
     steps:
       - checkout
       - run:
@@ -14,12 +14,12 @@ jobs:
 
   sanitize:
     docker:
-      - image: redislabsmodules/llvm-toolset:latest
+      - image: silkeh/clang:12
     steps:
       - checkout
       - run:
           name: Install CMAKE
-          command: 'apt install -y cmake'
+          command: 'apt install -y cmake --fix-missing'
       - run:
           name: Pull Submodules
           command: git submodule update --init --recursive

CMakeLists.txt

@@ -12,6 +12,7 @@ option(BUILD_BENCHMARK "Build benchmark" ON)
 option(BUILD_TESTS "Build tests" ON)
 OPTION(ENABLE_CODECOVERAGE "Enable code coverage testing support" OFF)
 OPTION(ENABLE_PROFILE "Enable code profiling support" OFF)
+option(ENABLE_FUZZER "Enable fuzz testing" OFF)
 option(BUILD_EXAMPLES "Build examples" ON)
 
 # --- Build properties ---

Makefile

@@ -77,6 +77,7 @@ ifndef CMAKE_TEST_OPTIONS
 	CMAKE_TEST_OPTIONS=\
 		-DBUILD_SHARED=ON \
 		-DBUILD_STATIC=ON \
+		-DENABLE_FUZZER=ON \
 		-DBUILD_TESTS=ON \
 		-DENABLE_CODECOVERAGE=ON \
 		-DBUILD_BENCHMARK=OFF \

tests/CMakeLists.txt

@@ -18,3 +18,18 @@ add_executable(td_test td_test.c minunit.h)
 target_link_libraries(td_test tdigest m)
 enable_testing()
 add_test(td_test td_test)
+
+
+# --- Fuzz testing ---
+if (ENABLE_FUZZER)
+  message(STATUS "Forcing compiler to be clang given we're using libfuzz.")
+  set(CMAKE_C_COMPILER clang)
+  set(CMAKE_CXX_COMPILER clang)
+  add_executable(td_fuzz test_fuzzer.cc)
+  target_compile_options(td_fuzz PRIVATE $<$<C_COMPILER_ID:Clang>:-g -O1
+                                          -fsanitize=fuzzer>)
+
+  target_link_libraries(td_fuzz
+                        PRIVATE $<$<C_COMPILER_ID:Clang>:-fsanitize=fuzzer> tdigest)
+  add_test(td_fuzz td_fuzz)
+endif()

tests/test_fuzzer.cc

@@ -0,0 +1,10 @@
+// Test_fuzzer.cc
+#include <stdint.h>
+#include <stddef.h>
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size > 0 && data[0] == 'H')
+    if (size > 1 && data[1] == 'I')
+       if (size > 2 && data[2] == '!')
+       __builtin_trap();
+  return 0;
+}