namespace fuzzer {
+typedef size_t (MutationDispatcher::*Mutator)(uint8_t *Data, size_t Size,
+ size_t Max);
+
+struct MutationDispatcher::Impl {
+ std::vector<Unit> Dictionary;
+ std::vector<Mutator> Mutators;
+ Impl() {
+ Mutators.push_back(&MutationDispatcher::Mutate_EraseByte);
+ Mutators.push_back(&MutationDispatcher::Mutate_InsertByte);
+ Mutators.push_back(&MutationDispatcher::Mutate_ChangeByte);
+ Mutators.push_back(&MutationDispatcher::Mutate_ChangeBit);
+ Mutators.push_back(&MutationDispatcher::Mutate_ShuffleBytes);
+ Mutators.push_back(&MutationDispatcher::Mutate_ChangeASCIIInteger);
+ }
+ void AddWordToDictionary(const uint8_t *Word, size_t Size) {
+ if (Dictionary.empty()) {
+ Mutators.push_back(&MutationDispatcher::Mutate_AddWordFromDictionary);
+ }
+ Dictionary.push_back(Unit(Word, Word + Size));
+ }
+};
+
+
static char FlipRandomBit(char X, FuzzerRandomBase &Rand) {
int Bit = Rand(8);
char Mask = 1 << Bit;
size_t MutationDispatcher::Mutate_EraseByte(uint8_t *Data, size_t Size,
size_t MaxSize) {
assert(Size);
- if (Size == 1) return Size;
+ if (Size == 1) return 0;
size_t Idx = Rand(Size);
// Erase Data[Idx].
memmove(Data + Idx, Data + Idx + 1, Size - Idx - 1);
size_t MutationDispatcher::Mutate_InsertByte(uint8_t *Data, size_t Size,
size_t MaxSize) {
- if (Size == MaxSize) return Size;
+ if (Size == MaxSize) return 0;
size_t Idx = Rand(Size + 1);
// Insert new value at Data[Idx].
memmove(Data + Idx + 1, Data + Idx, Size - Idx);
return Size;
}
+size_t MutationDispatcher::Mutate_AddWordFromDictionary(uint8_t *Data,
+ size_t Size,
+ size_t MaxSize) {
+ auto &D = MDImpl->Dictionary;
+ assert(!D.empty());
+ if (D.empty()) return 0;
+ const Unit &Word = D[Rand(D.size())];
+ if (Size + Word.size() > MaxSize) return 0;
+ size_t Idx = Rand(Size + 1);
+ memmove(Data + Idx + Word.size(), Data + Idx, Size - Idx);
+ memcpy(Data + Idx, Word.data(), Word.size());
+ return Size + Word.size();
+}
+
+size_t MutationDispatcher::Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size,
+ size_t MaxSize) {
+ size_t B = Rand(Size);
+ while (B < Size && !isdigit(Data[B])) B++;
+ if (B == Size) return 0;
+ size_t E = B;
+ while (E < Size && isdigit(Data[E])) E++;
+ assert(B < E);
+ // now we have digits in [B, E).
+ // strtol and friends don't accept non-zero-teminated data, parse it manually.
+ uint64_t Val = Data[B] - '0';
+ for (size_t i = B + 1; i < E; i++)
+ Val = Val * 10 + Data[i] - '0';
+
+ // Mutate the integer value.
+ switch(Rand(5)) {
+ case 0: Val++; break;
+ case 1: Val--; break;
+ case 2: Val /= 2; break;
+ case 3: Val *= 2; break;
+ case 4: Val = Rand(Val * Val); break;
+ default: assert(0);
+ }
+ // Just replace the bytes with the new ones, don't bother moving bytes.
+ for (size_t i = B; i < E; i++) {
+ size_t Idx = E + B - i - 1;
+ assert(Idx >= B && Idx < E);
+ Data[Idx] = (Val % 10) + '0';
+ Val /= 10;
+ }
+ return Size;
+}
+
// Mutates Data in place, returns new size.
size_t MutationDispatcher::Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
assert(MaxSize > 0);
return MaxSize;
}
assert(Size > 0);
- switch (Rand(5)) {
- case 0: Size = Mutate_EraseByte(Data, Size, MaxSize); break;
- case 1: Size = Mutate_InsertByte(Data, Size, MaxSize); break;
- case 2: Size = Mutate_ChangeByte(Data, Size, MaxSize); break;
- case 3: Size = Mutate_ChangeBit(Data, Size, MaxSize); break;
- case 4: Size = Mutate_ShuffleBytes(Data, Size, MaxSize); break;
+ // Some mutations may fail (e.g. can't insert more bytes if Size == MaxSize),
+ // in which case they will return 0.
+ // Try several times before returning un-mutated data.
+ for (int Iter = 0; Iter < 10; Iter++) {
+ size_t MutatorIdx = Rand(MDImpl->Mutators.size());
+ size_t NewSize =
+ (this->*(MDImpl->Mutators[MutatorIdx]))(Data, Size, MaxSize);
+ if (NewSize) return NewSize;
}
- assert(Size > 0);
return Size;
}
+void MutationDispatcher::AddWordToDictionary(const uint8_t *Word, size_t Size) {
+ MDImpl->AddWordToDictionary(Word, Size);
+}
+
+MutationDispatcher::MutationDispatcher(FuzzerRandomBase &Rand) : Rand(Rand) {
+ MDImpl = new Impl;
+}
+
+MutationDispatcher::~MutationDispatcher() { delete MDImpl; }
+
} // namespace fuzzer