1 //===- FuzzerInterface.h - Interface header for the Fuzzer ------*- C++ -* ===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
9 // Define the interface between the Fuzzer and the library being tested.
10 //===----------------------------------------------------------------------===//
12 // WARNING: keep the interface free of STL or any other header-based C++ lib,
13 // to avoid bad interactions between the code used in the fuzzer and
14 // the code used in the target function.
16 #ifndef LLVM_FUZZER_INTERFACE_H
17 #define LLVM_FUZZER_INTERFACE_H
24 typedef void (*UserCallback)(const uint8_t *Data, size_t Size);
25 /** Simple C-like interface with a single user-supplied callback.
30 #include "FuzzerInterface.h"
32 void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
33 DoStuffWithData(Data, Size);
36 // Implement your own main() or use the one from FuzzerMain.cpp.
37 int main(int argc, char **argv) {
38 InitializeMeIfNeeded();
39 return fuzzer::FuzzerDriver(argc, argv, LLVMFuzzerTestOneInput);
43 int FuzzerDriver(int argc, char **argv, UserCallback Callback);
45 class FuzzerRandomBase {
48 virtual ~FuzzerRandomBase(){};
49 virtual void ResetSeed(int seed) = 0;
50 // Return a random number.
51 virtual size_t Rand() = 0;
52 // Return a random number in range [0,n).
53 size_t operator()(size_t n) { return n ? Rand() % n : 0; }
54 bool RandBool() { return Rand() % 2; }
57 class FuzzerRandomLibc : public FuzzerRandomBase {
59 FuzzerRandomLibc(int seed) { ResetSeed(seed); }
60 void ResetSeed(int seed) override;
61 ~FuzzerRandomLibc() override {}
62 size_t Rand() override;
65 class MutationDispatcher {
67 MutationDispatcher(FuzzerRandomBase &Rand);
68 ~MutationDispatcher();
69 /// Mutates data by shuffling bytes.
70 size_t Mutate_ShuffleBytes(uint8_t *Data, size_t Size, size_t MaxSize);
71 /// Mutates data by erasing a byte.
72 size_t Mutate_EraseByte(uint8_t *Data, size_t Size, size_t MaxSize);
73 /// Mutates data by inserting a byte.
74 size_t Mutate_InsertByte(uint8_t *Data, size_t Size, size_t MaxSize);
75 /// Mutates data by chanding one byte.
76 size_t Mutate_ChangeByte(uint8_t *Data, size_t Size, size_t MaxSize);
77 /// Mutates data by chanding one bit.
78 size_t Mutate_ChangeBit(uint8_t *Data, size_t Size, size_t MaxSize);
80 /// Mutates data by adding a word from the dictionary.
81 size_t Mutate_AddWordFromDictionary(uint8_t *Data, size_t Size,
84 /// Applies one of the above mutations.
85 /// Returns the new size of data which could be up to MaxSize.
86 size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize);
88 /// Creates a cross-over of two pieces of Data, returns its size.
89 size_t CrossOver(const uint8_t *Data1, size_t Size1, const uint8_t *Data2,
90 size_t Size2, uint8_t *Out, size_t MaxOutSize);
92 void AddWordToDictionary(const uint8_t *Word, size_t Size);
95 FuzzerRandomBase &Rand;
100 // For backward compatibility only, deprecated.
101 static inline size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize,
102 FuzzerRandomBase &Rand) {
103 MutationDispatcher MD(Rand);
104 return MD.Mutate(Data, Size, MaxSize);
107 /** An abstract class that allows to use user-supplied mutators with libFuzzer.
112 #include "FuzzerInterface.h"
113 class MyFuzzer : public fuzzer::UserSuppliedFuzzer {
115 MyFuzzer(fuzzer::FuzzerRandomBase *Rand);
116 // Must define the target function.
117 void TargetFunction(...) { ... }
118 // Optionally define the mutator.
119 size_t Mutate(...) { ... }
120 // Optionally define the CrossOver method.
121 size_t CrossOver(...) { ... }
124 int main(int argc, char **argv) {
126 fuzzer::FuzzerDriver(argc, argv, F);
130 class UserSuppliedFuzzer {
132 UserSuppliedFuzzer(); // Deprecated, don't use.
133 UserSuppliedFuzzer(FuzzerRandomBase *Rand);
134 /// Executes the target function on 'Size' bytes of 'Data'.
135 virtual void TargetFunction(const uint8_t *Data, size_t Size) = 0;
136 /// Mutates 'Size' bytes of data in 'Data' inplace into up to 'MaxSize' bytes,
137 /// returns the new size of the data, which should be positive.
138 virtual size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
139 return MD.Mutate(Data, Size, MaxSize);
141 /// Crosses 'Data1' and 'Data2', writes up to 'MaxOutSize' bytes into Out,
142 /// returns the number of bytes written, which should be positive.
143 virtual size_t CrossOver(const uint8_t *Data1, size_t Size1,
144 const uint8_t *Data2, size_t Size2,
145 uint8_t *Out, size_t MaxOutSize) {
146 return MD.CrossOver(Data1, Size1, Data2, Size2, Out, MaxOutSize);
148 virtual ~UserSuppliedFuzzer();
150 FuzzerRandomBase &GetRand() { return *Rand; }
152 MutationDispatcher &GetMD() { return MD; }
155 bool OwnRand = false;
156 FuzzerRandomBase *Rand;
157 MutationDispatcher MD;
160 /// Runs the fuzzing with the UserSuppliedFuzzer.
161 int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF);
163 } // namespace fuzzer
165 #endif // LLVM_FUZZER_INTERFACE_H