fix libfuzzer custom mutator and add introspection function

custom_mutators/libfuzzer/FuzzerIO.cpp

@@ -83,6 +83,8 @@ void WriteToFile(const std::string &Data, const std::string &Path) {
 
 void WriteToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
 
+  return;
+ 
   // Use raw C interface because this function may be called from a sig handler.
   FILE *Out = fopen(Path.c_str(), "wb");
   if (!Out) return;
@@ -93,6 +95,8 @@ void WriteToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
 
 void AppendToFile(const std::string &Data, const std::string &Path) {
 
+  return;
+
   AppendToFile(reinterpret_cast<const uint8_t *>(Data.data()), Data.size(),
                Path);
 
@@ -100,6 +104,8 @@ void AppendToFile(const std::string &Data, const std::string &Path) {
 
 void AppendToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
 
+  return;
+
   FILE *Out = fopen(Path.c_str(), "a");
   if (!Out) return;
   fwrite(Data, sizeof(Data[0]), Size, Out);
@@ -182,6 +188,7 @@ void Printf(const char *Fmt, ...) {
 
 void VPrintf(bool Verbose, const char *Fmt, ...) {
 
+  return;
   if (!Verbose) return;
   va_list ap;
   va_start(ap, Fmt);

custom_mutators/libfuzzer/FuzzerLoop.cpp

@@ -206,6 +206,8 @@ void Fuzzer::StaticDeathCallback() {
 
 void Fuzzer::DumpCurrentUnit(const char *Prefix) {
 
+  return;
+
   if (!CurrentUnitData) return;  // Happens when running individual inputs.
   ScopedDisableMsanInterceptorChecks S;
   MD.PrintMutationSequence();
@@ -733,6 +735,7 @@ std::string Fuzzer::WriteToOutputCorpus(const Unit &U) {
 
 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
 
+  return;
   if (!Options.SaveArtifacts) return;
   std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
   if (!Options.ExactArtifactPath.empty())
@@ -1073,13 +1076,21 @@ void Fuzzer::MinimizeCrashLoop(const Unit &U) {
 
 }  // namespace fuzzer
 
+#ifdef  INTROSPECTION
+  extern const char *introspection_ptr;
+#endif
+
 extern "C" {
 
 ATTRIBUTE_INTERFACE size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size,
                                             size_t MaxSize) {
 
   assert(fuzzer::F);
-  return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
+  size_t r = fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
+#ifdef  INTROSPECTION
+  introspection_ptr = fuzzer::F->GetMD().WriteMutationSequence();
+#endif
+  return r;
 
 }
 

custom_mutators/libfuzzer/FuzzerMutate.cpp

@@ -14,6 +14,8 @@
 #include "FuzzerMutate.h"
 #include "FuzzerOptions.h"
 #include "FuzzerTracePC.h"
+#include <random>
+#include <chrono>
 
 namespace fuzzer {
 
@@ -100,15 +102,17 @@ size_t MutationDispatcher::Mutate_CustomCrossOver(uint8_t *Data, size_t Size,
 
 }
 
+
 size_t MutationDispatcher::Mutate_ShuffleBytes(uint8_t *Data, size_t Size,
                                                size_t MaxSize) {
-
   if (Size > MaxSize || Size == 0) return 0;
   size_t ShuffleAmount =
       Rand(std::min(Size, (size_t)8)) + 1;  // [1,8] and <= Size.
   size_t ShuffleStart = Rand(Size - ShuffleAmount);
   assert(ShuffleStart + ShuffleAmount <= Size);
-  std::shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount, Rand);
+  unsigned num = std::chrono::system_clock::now().time_since_epoch().count();
+  std::shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount, std::default_random_engine(num));
+  //std::shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount, Rand);
   return Size;
 
 }
@@ -609,8 +613,24 @@ void MutationDispatcher::PrintRecommendedDictionary() {
 
 }
 
+const char *MutationDispatcher::WriteMutationSequence() {
+
+  static std::string buf;
+  buf = "";
+
+  for (size_t i = 0; i < CurrentMutatorSequence.size(); i++) {
+  
+    buf = buf + " " + CurrentMutatorSequence[i].Name;
+  
+  }
+  
+  return buf.c_str();
+
+}
+
 void MutationDispatcher::PrintMutationSequence(bool Verbose) {
 
+  return;
   Printf("MS: %zd ", CurrentMutatorSequence.size());
   size_t EntriesToPrint =
       Verbose ? CurrentMutatorSequence.size()

custom_mutators/libfuzzer/FuzzerMutate.h

@@ -26,6 +26,7 @@ public:
   void StartMutationSequence();
   /// Print the current sequence of mutations. Only prints the full sequence
   /// when Verbose is true.
+  const char *WriteMutationSequence();
   void PrintMutationSequence(bool Verbose = true);
   /// Return the current sequence of mutations.
   std::string MutationSequence();

custom_mutators/libfuzzer/Makefile

@@ -3,6 +3,11 @@ CFLAGS = -g -O3 -funroll-loops -fPIC -fpermissive -std=c++11
 #CFLAGS = -g -O0 -fPIC -fpermissive -std=c++11
 CXX ?= clang++
 
+ifdef INTROSPECTION
+  $(info Compiling with introspection documentation)
+  CFLAGS += -DINTROSPECTION=1
+endif
+
 all: libfuzzer-mutator.so
 
 FuzzerCrossOver.o:	FuzzerCrossOver.cpp

custom_mutators/libfuzzer/libfuzzer.cpp

@@ -6,6 +6,10 @@
 //#include "debug.h"
 #include "afl-fuzz.h"
 
+#ifdef  INTROSPECTION
+  const char *introspection_ptr;
+#endif
+
 afl_state_t *afl_struct;
 
 extern "C" size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize);
@@ -133,6 +137,14 @@ extern "C" size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf,
 
 }
 
+#ifdef  INTROSPECTION
+extern "C" const char* afl_custom_introspection(my_mutator_t *data) {
+
+  return introspection_ptr;
+
+}
+#endif
+
 /**
  * Deinitialize everything
  *