// Define the interface between the Fuzzer and the library being tested.
//===----------------------------------------------------------------------===//
+// WARNING: keep the interface free of STL or any other header-based C++ lib,
+// to avoid bad interactions between the code used in the fuzzer and
+// the code used in the target function.
+
#ifndef LLVM_FUZZER_INTERFACE_H
#define LLVM_FUZZER_INTERFACE_H
#include <cstddef>
#include <cstdint>
+#include <vector>
+#include <string>
namespace fuzzer {
-typedef void (*UserCallback)(const uint8_t *data, size_t size);
+/// Returns an int 0. Values other than zero are reserved for future.
+typedef int (*UserCallback)(const uint8_t *Data, size_t Size);
+/** Simple C-like interface with a single user-supplied callback.
+
+Usage:
+
+#\code
+#include "FuzzerInterface.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+ DoStuffWithData(Data, Size);
+ return 0;
+}
+
+// Implement your own main() or use the one from FuzzerMain.cpp.
+int main(int argc, char **argv) {
+ InitializeMeIfNeeded();
+ return fuzzer::FuzzerDriver(argc, argv, LLVMFuzzerTestOneInput);
+}
+#\endcode
+*/
int FuzzerDriver(int argc, char **argv, UserCallback Callback);
+class FuzzerRandomBase {
+ public:
+ FuzzerRandomBase(){}
+ virtual ~FuzzerRandomBase(){};
+ virtual void ResetSeed(int seed) = 0;
+ // Return a random number.
+ virtual size_t Rand() = 0;
+ // Return a random number in range [0,n).
+ size_t operator()(size_t n) { return n ? Rand() % n : 0; }
+ bool RandBool() { return Rand() % 2; }
+};
+
+class FuzzerRandomLibc : public FuzzerRandomBase {
+ public:
+ FuzzerRandomLibc(int seed) { ResetSeed(seed); }
+ void ResetSeed(int seed) override;
+ ~FuzzerRandomLibc() override {}
+ size_t Rand() override;
+};
+
+class MutationDispatcher {
+ public:
+ MutationDispatcher(FuzzerRandomBase &Rand);
+ ~MutationDispatcher();
+ /// Mutates data by shuffling bytes.
+ size_t Mutate_ShuffleBytes(uint8_t *Data, size_t Size, size_t MaxSize);
+ /// Mutates data by erasing a byte.
+ size_t Mutate_EraseByte(uint8_t *Data, size_t Size, size_t MaxSize);
+ /// Mutates data by inserting a byte.
+ size_t Mutate_InsertByte(uint8_t *Data, size_t Size, size_t MaxSize);
+ /// Mutates data by chanding one byte.
+ size_t Mutate_ChangeByte(uint8_t *Data, size_t Size, size_t MaxSize);
+ /// Mutates data by chanding one bit.
+ size_t Mutate_ChangeBit(uint8_t *Data, size_t Size, size_t MaxSize);
+
+ /// Mutates data by adding a word from the dictionary.
+ size_t Mutate_AddWordFromDictionary(uint8_t *Data, size_t Size,
+ size_t MaxSize);
+
+ size_t Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size, size_t MaxSize);
+
+ /// Applies one of the above mutations.
+ /// Returns the new size of data which could be up to MaxSize.
+ size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize);
+
+ /// Creates a cross-over of two pieces of Data, returns its size.
+ size_t CrossOver(const uint8_t *Data1, size_t Size1, const uint8_t *Data2,
+ size_t Size2, uint8_t *Out, size_t MaxOutSize);
+
+ void AddWordToDictionary(const uint8_t *Word, size_t Size);
+
+ private:
+ FuzzerRandomBase &Rand;
+ struct Impl;
+ Impl *MDImpl;
+};
+
+// For backward compatibility only, deprecated.
+static inline size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize,
+ FuzzerRandomBase &Rand) {
+ MutationDispatcher MD(Rand);
+ return MD.Mutate(Data, Size, MaxSize);
+}
+
+/** An abstract class that allows to use user-supplied mutators with libFuzzer.
+
+Usage:
+
+#\code
+#include "FuzzerInterface.h"
+class MyFuzzer : public fuzzer::UserSuppliedFuzzer {
+ public:
+ MyFuzzer(fuzzer::FuzzerRandomBase *Rand);
+ // Must define the target function.
+ int TargetFunction(...) { ...; return 0; }
+ // Optionally define the mutator.
+ size_t Mutate(...) { ... }
+ // Optionally define the CrossOver method.
+ size_t CrossOver(...) { ... }
+};
+
+int main(int argc, char **argv) {
+ MyFuzzer F;
+ fuzzer::FuzzerDriver(argc, argv, F);
+}
+#\endcode
+*/
+class UserSuppliedFuzzer {
+ public:
+ UserSuppliedFuzzer(FuzzerRandomBase *Rand);
+ /// Executes the target function on 'Size' bytes of 'Data'.
+ virtual int TargetFunction(const uint8_t *Data, size_t Size) = 0;
+ /// Mutates 'Size' bytes of data in 'Data' inplace into up to 'MaxSize' bytes,
+ /// returns the new size of the data, which should be positive.
+ virtual size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+ return MD.Mutate(Data, Size, MaxSize);
+ }
+ /// Crosses 'Data1' and 'Data2', writes up to 'MaxOutSize' bytes into Out,
+ /// returns the number of bytes written, which should be positive.
+ virtual size_t CrossOver(const uint8_t *Data1, size_t Size1,
+ const uint8_t *Data2, size_t Size2,
+ uint8_t *Out, size_t MaxOutSize) {
+ return MD.CrossOver(Data1, Size1, Data2, Size2, Out, MaxOutSize);
+ }
+ virtual ~UserSuppliedFuzzer();
+
+ FuzzerRandomBase &GetRand() { return *Rand; }
+
+ MutationDispatcher &GetMD() { return MD; }
+
+ private:
+ bool OwnRand = false;
+ FuzzerRandomBase *Rand;
+ MutationDispatcher MD;
+};
+
+/// Runs the fuzzing with the UserSuppliedFuzzer.
+int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF);
+
+/// More C++-ish interface.
+int FuzzerDriver(const std::vector<std::string> &Args, UserSuppliedFuzzer &USF);
+int FuzzerDriver(const std::vector<std::string> &Args, UserCallback Callback);
+
} // namespace fuzzer
#endif // LLVM_FUZZER_INTERFACE_H