1 //===- FuzzerMutate.cpp - Mutate a test input -----------------------------===//
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 // Mutate a test input.
10 //===----------------------------------------------------------------------===//
12 #include "FuzzerMutate.h"
13 #include "FuzzerCorpus.h"
14 #include "FuzzerDefs.h"
15 #include "FuzzerExtFunctions.h"
17 #include "FuzzerOptions.h"
21 const size_t Dictionary::kMaxDictSize;
23 static void PrintASCII(const Word &W, const char *PrintAfter) {
24 PrintASCII(W.data(), W.size(), PrintAfter);
27 MutationDispatcher::MutationDispatcher(Random &Rand,
28 const FuzzingOptions &Options)
29 : Rand(Rand), Options(Options) {
30 DefaultMutators.insert(
31 DefaultMutators.begin(),
33 {&MutationDispatcher::Mutate_EraseBytes, "EraseBytes"},
34 {&MutationDispatcher::Mutate_InsertByte, "InsertByte"},
35 {&MutationDispatcher::Mutate_InsertRepeatedBytes,
36 "InsertRepeatedBytes"},
37 {&MutationDispatcher::Mutate_ChangeByte, "ChangeByte"},
38 {&MutationDispatcher::Mutate_ChangeBit, "ChangeBit"},
39 {&MutationDispatcher::Mutate_ShuffleBytes, "ShuffleBytes"},
40 {&MutationDispatcher::Mutate_ChangeASCIIInteger, "ChangeASCIIInt"},
41 {&MutationDispatcher::Mutate_ChangeBinaryInteger, "ChangeBinInt"},
42 {&MutationDispatcher::Mutate_CopyPart, "CopyPart"},
43 {&MutationDispatcher::Mutate_CrossOver, "CrossOver"},
44 {&MutationDispatcher::Mutate_AddWordFromManualDictionary,
46 {&MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary,
50 DefaultMutators.push_back(
51 {&MutationDispatcher::Mutate_AddWordFromTORC, "CMP"});
53 if (EF->LLVMFuzzerCustomMutator)
54 Mutators.push_back({&MutationDispatcher::Mutate_Custom, "Custom"});
56 Mutators = DefaultMutators;
58 if (EF->LLVMFuzzerCustomCrossOver)
60 {&MutationDispatcher::Mutate_CustomCrossOver, "CustomCrossOver"});
63 static char RandCh(Random &Rand) {
64 if (Rand.RandBool()) return Rand(256);
65 const char Special[] = "!*'();:@&=+$,/?%#[]012Az-`~.\xff\x00";
66 return Special[Rand(sizeof(Special) - 1)];
69 size_t MutationDispatcher::Mutate_Custom(uint8_t *Data, size_t Size,
71 return EF->LLVMFuzzerCustomMutator(Data, Size, MaxSize, Rand.Rand());
74 size_t MutationDispatcher::Mutate_CustomCrossOver(uint8_t *Data, size_t Size,
76 if (!Corpus || Corpus->size() < 2 || Size == 0)
78 size_t Idx = Rand(Corpus->size());
79 const Unit &Other = (*Corpus)[Idx];
82 CustomCrossOverInPlaceHere.resize(MaxSize);
83 auto &U = CustomCrossOverInPlaceHere;
84 size_t NewSize = EF->LLVMFuzzerCustomCrossOver(
85 Data, Size, Other.data(), Other.size(), U.data(), U.size(), Rand.Rand());
88 assert(NewSize <= MaxSize && "CustomCrossOver returned overisized unit");
89 memcpy(Data, U.data(), NewSize);
93 size_t MutationDispatcher::Mutate_ShuffleBytes(uint8_t *Data, size_t Size,
95 if (Size > MaxSize || Size == 0) return 0;
96 size_t ShuffleAmount =
97 Rand(std::min(Size, (size_t)8)) + 1; // [1,8] and <= Size.
98 size_t ShuffleStart = Rand(Size - ShuffleAmount);
99 assert(ShuffleStart + ShuffleAmount <= Size);
100 std::shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount, Rand);
104 size_t MutationDispatcher::Mutate_EraseBytes(uint8_t *Data, size_t Size,
106 if (Size <= 1) return 0;
107 size_t N = Rand(Size / 2) + 1;
109 size_t Idx = Rand(Size - N + 1);
110 // Erase Data[Idx:Idx+N].
111 memmove(Data + Idx, Data + Idx + N, Size - Idx - N);
112 // Printf("Erase: %zd %zd => %zd; Idx %zd\n", N, Size, Size - N, Idx);
116 size_t MutationDispatcher::Mutate_InsertByte(uint8_t *Data, size_t Size,
118 if (Size >= MaxSize) return 0;
119 size_t Idx = Rand(Size + 1);
120 // Insert new value at Data[Idx].
121 memmove(Data + Idx + 1, Data + Idx, Size - Idx);
122 Data[Idx] = RandCh(Rand);
126 size_t MutationDispatcher::Mutate_InsertRepeatedBytes(uint8_t *Data,
129 const size_t kMinBytesToInsert = 3;
130 if (Size + kMinBytesToInsert >= MaxSize) return 0;
131 size_t MaxBytesToInsert = std::min(MaxSize - Size, (size_t)128);
132 size_t N = Rand(MaxBytesToInsert - kMinBytesToInsert + 1) + kMinBytesToInsert;
133 assert(Size + N <= MaxSize && N);
134 size_t Idx = Rand(Size + 1);
135 // Insert new values at Data[Idx].
136 memmove(Data + Idx + N, Data + Idx, Size - Idx);
137 // Give preference to 0x00 and 0xff.
138 uint8_t Byte = Rand.RandBool() ? Rand(256) : (Rand.RandBool() ? 0 : 255);
139 for (size_t i = 0; i < N; i++)
140 Data[Idx + i] = Byte;
144 size_t MutationDispatcher::Mutate_ChangeByte(uint8_t *Data, size_t Size,
146 if (Size > MaxSize) return 0;
147 size_t Idx = Rand(Size);
148 Data[Idx] = RandCh(Rand);
152 size_t MutationDispatcher::Mutate_ChangeBit(uint8_t *Data, size_t Size,
154 if (Size > MaxSize) return 0;
155 size_t Idx = Rand(Size);
156 Data[Idx] ^= 1 << Rand(8);
160 size_t MutationDispatcher::Mutate_AddWordFromManualDictionary(uint8_t *Data,
163 return AddWordFromDictionary(ManualDictionary, Data, Size, MaxSize);
166 size_t MutationDispatcher::ApplyDictionaryEntry(uint8_t *Data, size_t Size,
168 DictionaryEntry &DE) {
169 const Word &W = DE.GetW();
170 bool UsePositionHint = DE.HasPositionHint() &&
171 DE.GetPositionHint() + W.size() < Size &&
173 if (Rand.RandBool()) { // Insert W.
174 if (Size + W.size() > MaxSize) return 0;
175 size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size + 1);
176 memmove(Data + Idx + W.size(), Data + Idx, Size - Idx);
177 memcpy(Data + Idx, W.data(), W.size());
179 } else { // Overwrite some bytes with W.
180 if (W.size() > Size) return 0;
181 size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size - W.size());
182 memcpy(Data + Idx, W.data(), W.size());
187 // Somewhere in the past we have observed a comparison instructions
188 // with arguments Arg1 Arg2. This function tries to guess a dictionary
189 // entry that will satisfy that comparison.
190 // It first tries to find one of the arguments (possibly swapped) in the
191 // input and if it succeeds it creates a DE with a position hint.
192 // Otherwise it creates a DE with one of the arguments w/o a position hint.
193 DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
194 const void *Arg1, const void *Arg2,
195 const void *Arg1Mutation, const void *Arg2Mutation,
196 size_t ArgSize, const uint8_t *Data,
198 bool HandleFirst = Rand.RandBool();
199 const void *ExistingBytes, *DesiredBytes;
201 const uint8_t *End = Data + Size;
202 for (int Arg = 0; Arg < 2; Arg++) {
203 ExistingBytes = HandleFirst ? Arg1 : Arg2;
204 DesiredBytes = HandleFirst ? Arg2Mutation : Arg1Mutation;
205 HandleFirst = !HandleFirst;
206 W.Set(reinterpret_cast<const uint8_t*>(DesiredBytes), ArgSize);
207 const size_t kMaxNumPositions = 8;
208 size_t Positions[kMaxNumPositions];
209 size_t NumPositions = 0;
210 for (const uint8_t *Cur = Data;
211 Cur < End && NumPositions < kMaxNumPositions; Cur++) {
213 (const uint8_t *)SearchMemory(Cur, End - Cur, ExistingBytes, ArgSize);
215 Positions[NumPositions++] = Cur - Data;
217 if (!NumPositions) continue;
218 return DictionaryEntry(W, Positions[Rand(NumPositions)]);
220 DictionaryEntry DE(W);
226 DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
227 T Arg1, T Arg2, const uint8_t *Data, size_t Size) {
228 if (Rand.RandBool()) Arg1 = Bswap(Arg1);
229 if (Rand.RandBool()) Arg2 = Bswap(Arg2);
230 T Arg1Mutation = Arg1 + Rand(-1, 1);
231 T Arg2Mutation = Arg2 + Rand(-1, 1);
232 return MakeDictionaryEntryFromCMP(&Arg1, &Arg2, &Arg1Mutation, &Arg2Mutation,
233 sizeof(Arg1), Data, Size);
236 DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
237 const Word &Arg1, const Word &Arg2, const uint8_t *Data, size_t Size) {
238 return MakeDictionaryEntryFromCMP(Arg1.data(), Arg2.data(), Arg1.data(),
239 Arg2.data(), Arg1.size(), Data, Size);
242 size_t MutationDispatcher::Mutate_AddWordFromTORC(
243 uint8_t *Data, size_t Size, size_t MaxSize) {
248 auto X = TPC.TORC8.Get(Rand.Rand());
249 DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
252 auto X = TPC.TORC4.Get(Rand.Rand());
253 if ((X.A >> 16) == 0 && (X.B >> 16) == 0 && Rand.RandBool())
254 DE = MakeDictionaryEntryFromCMP((uint16_t)X.A, (uint16_t)X.B, Data, Size);
256 DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
259 auto X = TPC.TORCW.Get(Rand.Rand());
260 DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
262 case 3: if (Options.UseMemmem) {
263 auto X = TPC.MMT.Get(Rand.Rand());
264 DE = DictionaryEntry(X);
269 if (!DE.GetW().size()) return 0;
270 Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
272 DictionaryEntry &DERef =
273 CmpDictionaryEntriesDeque[CmpDictionaryEntriesDequeIdx++ %
274 kCmpDictionaryEntriesDequeSize];
276 CurrentDictionaryEntrySequence.push_back(&DERef);
280 size_t MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary(
281 uint8_t *Data, size_t Size, size_t MaxSize) {
282 return AddWordFromDictionary(PersistentAutoDictionary, Data, Size, MaxSize);
285 size_t MutationDispatcher::AddWordFromDictionary(Dictionary &D, uint8_t *Data,
286 size_t Size, size_t MaxSize) {
287 if (Size > MaxSize) return 0;
288 if (D.empty()) return 0;
289 DictionaryEntry &DE = D[Rand(D.size())];
290 Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
293 CurrentDictionaryEntrySequence.push_back(&DE);
297 // Overwrites part of To[0,ToSize) with a part of From[0,FromSize).
299 size_t MutationDispatcher::CopyPartOf(const uint8_t *From, size_t FromSize,
300 uint8_t *To, size_t ToSize) {
301 // Copy From[FromBeg, FromBeg + CopySize) into To[ToBeg, ToBeg + CopySize).
302 size_t ToBeg = Rand(ToSize);
303 size_t CopySize = Rand(ToSize - ToBeg) + 1;
304 assert(ToBeg + CopySize <= ToSize);
305 CopySize = std::min(CopySize, FromSize);
306 size_t FromBeg = Rand(FromSize - CopySize + 1);
307 assert(FromBeg + CopySize <= FromSize);
308 memmove(To + ToBeg, From + FromBeg, CopySize);
312 // Inserts part of From[0,ToSize) into To.
313 // Returns new size of To on success or 0 on failure.
314 size_t MutationDispatcher::InsertPartOf(const uint8_t *From, size_t FromSize,
315 uint8_t *To, size_t ToSize,
317 if (ToSize >= MaxToSize) return 0;
318 size_t AvailableSpace = MaxToSize - ToSize;
319 size_t MaxCopySize = std::min(AvailableSpace, FromSize);
320 size_t CopySize = Rand(MaxCopySize) + 1;
321 size_t FromBeg = Rand(FromSize - CopySize + 1);
322 assert(FromBeg + CopySize <= FromSize);
323 size_t ToInsertPos = Rand(ToSize + 1);
324 assert(ToInsertPos + CopySize <= MaxToSize);
325 size_t TailSize = ToSize - ToInsertPos;
327 MutateInPlaceHere.resize(MaxToSize);
328 memcpy(MutateInPlaceHere.data(), From + FromBeg, CopySize);
329 memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
330 memmove(To + ToInsertPos, MutateInPlaceHere.data(), CopySize);
332 memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
333 memmove(To + ToInsertPos, From + FromBeg, CopySize);
335 return ToSize + CopySize;
338 size_t MutationDispatcher::Mutate_CopyPart(uint8_t *Data, size_t Size,
340 if (Size > MaxSize || Size == 0) return 0;
341 // If Size == MaxSize, `InsertPartOf(...)` will
342 // fail so there's no point using it in this case.
343 if (Size == MaxSize || Rand.RandBool())
344 return CopyPartOf(Data, Size, Data, Size);
346 return InsertPartOf(Data, Size, Data, Size, MaxSize);
349 size_t MutationDispatcher::Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size,
351 if (Size > MaxSize) return 0;
352 size_t B = Rand(Size);
353 while (B < Size && !isdigit(Data[B])) B++;
354 if (B == Size) return 0;
356 while (E < Size && isdigit(Data[E])) E++;
358 // now we have digits in [B, E).
359 // strtol and friends don't accept non-zero-teminated data, parse it manually.
360 uint64_t Val = Data[B] - '0';
361 for (size_t i = B + 1; i < E; i++)
362 Val = Val * 10 + Data[i] - '0';
364 // Mutate the integer value.
366 case 0: Val++; break;
367 case 1: Val--; break;
368 case 2: Val /= 2; break;
369 case 3: Val *= 2; break;
370 case 4: Val = Rand(Val * Val); break;
373 // Just replace the bytes with the new ones, don't bother moving bytes.
374 for (size_t i = B; i < E; i++) {
375 size_t Idx = E + B - i - 1;
376 assert(Idx >= B && Idx < E);
377 Data[Idx] = (Val % 10) + '0';
384 size_t ChangeBinaryInteger(uint8_t *Data, size_t Size, Random &Rand) {
385 if (Size < sizeof(T)) return 0;
386 size_t Off = Rand(Size - sizeof(T) + 1);
387 assert(Off + sizeof(T) <= Size);
389 if (Off < 64 && !Rand(4)) {
394 memcpy(&Val, Data + Off, sizeof(Val));
398 Val = Bswap(T(Bswap(Val) + Add)); // Add assuming different endiannes.
400 Val = Val + Add; // Add assuming current endiannes.
401 if (Add == 0 || Rand.RandBool()) // Maybe negate.
404 memcpy(Data + Off, &Val, sizeof(Val));
408 size_t MutationDispatcher::Mutate_ChangeBinaryInteger(uint8_t *Data,
411 if (Size > MaxSize) return 0;
413 case 3: return ChangeBinaryInteger<uint64_t>(Data, Size, Rand);
414 case 2: return ChangeBinaryInteger<uint32_t>(Data, Size, Rand);
415 case 1: return ChangeBinaryInteger<uint16_t>(Data, Size, Rand);
416 case 0: return ChangeBinaryInteger<uint8_t>(Data, Size, Rand);
422 size_t MutationDispatcher::Mutate_CrossOver(uint8_t *Data, size_t Size,
424 if (Size > MaxSize) return 0;
425 if (!Corpus || Corpus->size() < 2 || Size == 0) return 0;
426 size_t Idx = Rand(Corpus->size());
427 const Unit &O = (*Corpus)[Idx];
428 if (O.empty()) return 0;
429 MutateInPlaceHere.resize(MaxSize);
430 auto &U = MutateInPlaceHere;
434 NewSize = CrossOver(Data, Size, O.data(), O.size(), U.data(), U.size());
437 NewSize = InsertPartOf(O.data(), O.size(), U.data(), U.size(), MaxSize);
439 NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
442 NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
446 assert(NewSize > 0 && "CrossOver returned empty unit");
447 assert(NewSize <= MaxSize && "CrossOver returned overisized unit");
448 memcpy(Data, U.data(), NewSize);
452 void MutationDispatcher::StartMutationSequence() {
453 CurrentMutatorSequence.clear();
454 CurrentDictionaryEntrySequence.clear();
457 // Copy successful dictionary entries to PersistentAutoDictionary.
458 void MutationDispatcher::RecordSuccessfulMutationSequence() {
459 for (auto DE : CurrentDictionaryEntrySequence) {
460 // PersistentAutoDictionary.AddWithSuccessCountOne(DE);
461 DE->IncSuccessCount();
462 assert(DE->GetW().size());
463 // Linear search is fine here as this happens seldom.
464 if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
465 PersistentAutoDictionary.push_back({DE->GetW(), 1});
469 void MutationDispatcher::PrintRecommendedDictionary() {
470 Vector<DictionaryEntry> V;
471 for (auto &DE : PersistentAutoDictionary)
472 if (!ManualDictionary.ContainsWord(DE.GetW()))
474 if (V.empty()) return;
475 Printf("###### Recommended dictionary. ######\n");
477 assert(DE.GetW().size());
479 PrintASCII(DE.GetW(), "\"");
480 Printf(" # Uses: %zd\n", DE.GetUseCount());
482 Printf("###### End of recommended dictionary. ######\n");
485 void MutationDispatcher::PrintMutationSequence() {
486 Printf("MS: %zd ", CurrentMutatorSequence.size());
487 for (auto M : CurrentMutatorSequence)
488 Printf("%s-", M.Name);
489 if (!CurrentDictionaryEntrySequence.empty()) {
491 for (auto DE : CurrentDictionaryEntrySequence) {
493 PrintASCII(DE->GetW(), "\"-");
498 size_t MutationDispatcher::Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
499 return MutateImpl(Data, Size, MaxSize, Mutators);
502 size_t MutationDispatcher::DefaultMutate(uint8_t *Data, size_t Size,
504 return MutateImpl(Data, Size, MaxSize, DefaultMutators);
507 // Mutates Data in place, returns new size.
508 size_t MutationDispatcher::MutateImpl(uint8_t *Data, size_t Size,
510 Vector<Mutator> &Mutators) {
512 // Some mutations may fail (e.g. can't insert more bytes if Size == MaxSize),
513 // in which case they will return 0.
514 // Try several times before returning un-mutated data.
515 for (int Iter = 0; Iter < 100; Iter++) {
516 auto M = Mutators[Rand(Mutators.size())];
517 size_t NewSize = (this->*(M.Fn))(Data, Size, MaxSize);
518 if (NewSize && NewSize <= MaxSize) {
519 if (Options.OnlyASCII)
520 ToASCII(Data, NewSize);
521 CurrentMutatorSequence.push_back(M);
526 return 1; // Fallback, should not happen frequently.
529 // Mask represents the set of Data bytes that are worth mutating.
530 size_t MutationDispatcher::MutateWithMask(uint8_t *Data, size_t Size,
532 const Vector<uint8_t> &Mask) {
533 assert(Size <= Mask.size());
534 // * Copy the worthy bytes into a temporary array T
537 // This is totally unoptimized.
538 auto &T = MutateWithMaskTemp;
542 for (size_t I = 0; I < Size; I++)
544 T[OneBits++] = Data[I];
547 size_t NewSize = Mutate(T.data(), OneBits, OneBits);
548 assert(NewSize <= OneBits);
550 // Even if NewSize < OneBits we still use all OneBits bytes.
551 for (size_t I = 0, J = 0; I < Size; I++)
557 void MutationDispatcher::AddWordToManualDictionary(const Word &W) {
558 ManualDictionary.push_back(
559 {W, std::numeric_limits<size_t>::max()});
562 } // namespace fuzzer