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      1 //===- FuzzerMutate.h - Internal header for the Fuzzer ----------*- C++ -* ===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 // fuzzer::MutationDispatcher
     10 //===----------------------------------------------------------------------===//
     11 
     12 #ifndef LLVM_FUZZER_MUTATE_H
     13 #define LLVM_FUZZER_MUTATE_H
     14 
     15 #include "FuzzerDefs.h"
     16 #include "FuzzerDictionary.h"
     17 #include "FuzzerOptions.h"
     18 #include "FuzzerRandom.h"
     19 
     20 namespace fuzzer {
     21 
     22 class MutationDispatcher {
     23 public:
     24   MutationDispatcher(Random &Rand, const FuzzingOptions &Options);
     25   ~MutationDispatcher() {}
     26   /// Indicate that we are about to start a new sequence of mutations.
     27   void StartMutationSequence();
     28   /// Print the current sequence of mutations.
     29   void PrintMutationSequence();
     30   /// Indicate that the current sequence of mutations was successfull.
     31   void RecordSuccessfulMutationSequence();
     32   /// Mutates data by invoking user-provided mutator.
     33   size_t Mutate_Custom(uint8_t *Data, size_t Size, size_t MaxSize);
     34   /// Mutates data by invoking user-provided crossover.
     35   size_t Mutate_CustomCrossOver(uint8_t *Data, size_t Size, size_t MaxSize);
     36   /// Mutates data by shuffling bytes.
     37   size_t Mutate_ShuffleBytes(uint8_t *Data, size_t Size, size_t MaxSize);
     38   /// Mutates data by erasing bytes.
     39   size_t Mutate_EraseBytes(uint8_t *Data, size_t Size, size_t MaxSize);
     40   /// Mutates data by inserting a byte.
     41   size_t Mutate_InsertByte(uint8_t *Data, size_t Size, size_t MaxSize);
     42   /// Mutates data by inserting several repeated bytes.
     43   size_t Mutate_InsertRepeatedBytes(uint8_t *Data, size_t Size, size_t MaxSize);
     44   /// Mutates data by chanding one byte.
     45   size_t Mutate_ChangeByte(uint8_t *Data, size_t Size, size_t MaxSize);
     46   /// Mutates data by chanding one bit.
     47   size_t Mutate_ChangeBit(uint8_t *Data, size_t Size, size_t MaxSize);
     48   /// Mutates data by copying/inserting a part of data into a different place.
     49   size_t Mutate_CopyPart(uint8_t *Data, size_t Size, size_t MaxSize);
     50 
     51   /// Mutates data by adding a word from the manual dictionary.
     52   size_t Mutate_AddWordFromManualDictionary(uint8_t *Data, size_t Size,
     53                                             size_t MaxSize);
     54 
     55   /// Mutates data by adding a word from the temporary automatic dictionary.
     56   size_t Mutate_AddWordFromTemporaryAutoDictionary(uint8_t *Data, size_t Size,
     57                                                    size_t MaxSize);
     58 
     59   /// Mutates data by adding a word from the TORC.
     60   size_t Mutate_AddWordFromTORC(uint8_t *Data, size_t Size, size_t MaxSize);
     61 
     62   /// Mutates data by adding a word from the persistent automatic dictionary.
     63   size_t Mutate_AddWordFromPersistentAutoDictionary(uint8_t *Data, size_t Size,
     64                                                     size_t MaxSize);
     65 
     66   /// Tries to find an ASCII integer in Data, changes it to another ASCII int.
     67   size_t Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size, size_t MaxSize);
     68   /// Change a 1-, 2-, 4-, or 8-byte integer in interesting ways.
     69   size_t Mutate_ChangeBinaryInteger(uint8_t *Data, size_t Size, size_t MaxSize);
     70 
     71   /// CrossOver Data with some other element of the corpus.
     72   size_t Mutate_CrossOver(uint8_t *Data, size_t Size, size_t MaxSize);
     73 
     74   /// Applies one of the configured mutations.
     75   /// Returns the new size of data which could be up to MaxSize.
     76   size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize);
     77   /// Applies one of the default mutations. Provided as a service
     78   /// to mutation authors.
     79   size_t DefaultMutate(uint8_t *Data, size_t Size, size_t MaxSize);
     80 
     81   /// Creates a cross-over of two pieces of Data, returns its size.
     82   size_t CrossOver(const uint8_t *Data1, size_t Size1, const uint8_t *Data2,
     83                    size_t Size2, uint8_t *Out, size_t MaxOutSize);
     84 
     85   void AddWordToManualDictionary(const Word &W);
     86 
     87   void AddWordToAutoDictionary(DictionaryEntry DE);
     88   void ClearAutoDictionary();
     89   void PrintRecommendedDictionary();
     90 
     91   void SetCorpus(const InputCorpus *Corpus) { this->Corpus = Corpus; }
     92 
     93   Random &GetRand() { return Rand; }
     94 
     95 private:
     96 
     97   struct Mutator {
     98     size_t (MutationDispatcher::*Fn)(uint8_t *Data, size_t Size, size_t Max);
     99     const char *Name;
    100   };
    101 
    102   size_t AddWordFromDictionary(Dictionary &D, uint8_t *Data, size_t Size,
    103                                size_t MaxSize);
    104   size_t MutateImpl(uint8_t *Data, size_t Size, size_t MaxSize,
    105                     const std::vector<Mutator> &Mutators);
    106 
    107   size_t InsertPartOf(const uint8_t *From, size_t FromSize, uint8_t *To,
    108                       size_t ToSize, size_t MaxToSize);
    109   size_t CopyPartOf(const uint8_t *From, size_t FromSize, uint8_t *To,
    110                     size_t ToSize);
    111   size_t ApplyDictionaryEntry(uint8_t *Data, size_t Size, size_t MaxSize,
    112                               DictionaryEntry &DE);
    113 
    114   template <class T>
    115   DictionaryEntry MakeDictionaryEntryFromCMP(T Arg1, T Arg2,
    116                                              const uint8_t *Data, size_t Size);
    117   DictionaryEntry MakeDictionaryEntryFromCMP(const Word &Arg1, const Word &Arg2,
    118                                              const uint8_t *Data, size_t Size);
    119   DictionaryEntry MakeDictionaryEntryFromCMP(const void *Arg1, const void *Arg2,
    120                                              const void *Arg1Mutation,
    121                                              const void *Arg2Mutation,
    122                                              size_t ArgSize,
    123                                              const uint8_t *Data, size_t Size);
    124 
    125   Random &Rand;
    126   const FuzzingOptions Options;
    127 
    128   // Dictionary provided by the user via -dict=DICT_FILE.
    129   Dictionary ManualDictionary;
    130   // Temporary dictionary modified by the fuzzer itself,
    131   // recreated periodically.
    132   Dictionary TempAutoDictionary;
    133   // Persistent dictionary modified by the fuzzer, consists of
    134   // entries that led to successfull discoveries in the past mutations.
    135   Dictionary PersistentAutoDictionary;
    136 
    137   std::vector<Mutator> CurrentMutatorSequence;
    138   std::vector<DictionaryEntry *> CurrentDictionaryEntrySequence;
    139 
    140   static const size_t kCmpDictionaryEntriesDequeSize = 16;
    141   DictionaryEntry CmpDictionaryEntriesDeque[kCmpDictionaryEntriesDequeSize];
    142   size_t CmpDictionaryEntriesDequeIdx = 0;
    143 
    144   const InputCorpus *Corpus = nullptr;
    145   std::vector<uint8_t> MutateInPlaceHere;
    146   // CustomCrossOver needs its own buffer as a custom implementation may call
    147   // LLVMFuzzerMutate, which in turn may resize MutateInPlaceHere.
    148   std::vector<uint8_t> CustomCrossOverInPlaceHere;
    149 
    150   std::vector<Mutator> Mutators;
    151   std::vector<Mutator> DefaultMutators;
    152 };
    153 
    154 }  // namespace fuzzer
    155 
    156 #endif  // LLVM_FUZZER_MUTATE_H
    157