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llvm-mirror/lib/Fuzzer/FuzzerInternal.h
Kostya Serebryany 285f1f0e41 [sanitizer/coverage] Add AFL-style coverage counters (search heuristic for fuzzing).
Introduce -mllvm -sanitizer-coverage-8bit-counters=1
which adds imprecise thread-unfriendly 8-bit coverage counters.

The run-time library maps these 8-bit counters to 8-bit bitsets in the same way
AFL (http://lcamtuf.coredump.cx/afl/technical_details.txt) does:
counter values are divided into 8 ranges and based on the counter
value one of the bits in the bitset is set.
The AFL ranges are used here: 1, 2, 3, 4-7, 8-15, 16-31, 32-127, 128+.

These counters provide a search heuristic for single-threaded
coverage-guided fuzzers, we do not expect them to be useful for other purposes.

Depending on the value of -fsanitize-coverage=[123] flag,
these counters will be added to the function entry blocks (=1),
every basic block (=2), or every edge (=3).

Use these counters as an optional search heuristic in the Fuzzer library.
Add a test where this heuristic is critical.

llvm-svn: 231166
2015-03-03 23:27:02 +00:00

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3.5 KiB
C++

//===- FuzzerInternal.h - Internal header for the Fuzzer --------*- C++ -* ===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Define the main class fuzzer::Fuzzer and most functions.
//===----------------------------------------------------------------------===//
#include <cassert>
#include <climits>
#include <chrono>
#include <cstddef>
#include <cstdlib>
#include <string>
#include <vector>
#include <unordered_set>
#include "FuzzerInterface.h"
namespace fuzzer {
typedef std::vector<uint8_t> Unit;
using namespace std::chrono;
Unit ReadFile(const char *Path);
void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V);
void WriteToFile(const Unit &U, const std::string &Path);
void CopyFileToErr(const std::string &Path);
// Returns "Dir/FileName" or equivalent for the current OS.
std::string DirPlusFile(const std::string &DirPath,
const std::string &FileName);
void Mutate(Unit *U, size_t MaxLen);
void CrossOver(const Unit &A, const Unit &B, Unit *U, size_t MaxLen);
void Print(const Unit &U, const char *PrintAfter = "");
void PrintASCII(const Unit &U, const char *PrintAfter = "");
std::string Hash(const Unit &U);
void SetTimer(int Seconds);
class Fuzzer {
public:
struct FuzzingOptions {
int Verbosity = 1;
int MaxLen = 0;
bool DoCrossOver = true;
int MutateDepth = 5;
bool ExitOnFirst = false;
bool UseCounters = false;
bool UseFullCoverageSet = false;
bool UseCoveragePairs = false;
int PreferSmallDuringInitialShuffle = -1;
size_t MaxNumberOfRuns = ULONG_MAX;
std::string OutputCorpus;
};
Fuzzer(UserCallback Callback, FuzzingOptions Options)
: Callback(Callback), Options(Options) {
SetDeathCallback();
}
void AddToCorpus(const Unit &U) { Corpus.push_back(U); }
size_t Loop(size_t NumIterations);
void ShuffleAndMinimize();
size_t CorpusSize() const { return Corpus.size(); }
void ReadDir(const std::string &Path) {
ReadDirToVectorOfUnits(Path.c_str(), &Corpus);
}
// Save the current corpus to OutputCorpus.
void SaveCorpus();
size_t secondsSinceProcessStartUp() {
return duration_cast<seconds>(system_clock::now() - ProcessStartTime)
.count();
}
size_t getTotalNumberOfRuns() { return TotalNumberOfRuns; }
static void AlarmCallback();
private:
size_t MutateAndTestOne(Unit *U);
size_t RunOne(const Unit &U);
size_t RunOneMaximizeTotalCoverage(const Unit &U);
size_t RunOneMaximizeFullCoverageSet(const Unit &U);
size_t RunOneMaximizeCoveragePairs(const Unit &U);
void WriteToOutputCorpus(const Unit &U);
static void WriteToCrash(const Unit &U, const char *Prefix);
void SetDeathCallback();
static void DeathCallback();
static Unit CurrentUnit;
size_t TotalNumberOfRuns = 0;
std::vector<Unit> Corpus;
std::unordered_set<uintptr_t> FullCoverageSets;
std::unordered_set<uint64_t> CoveragePairs;
// For UseCounters
std::vector<uint8_t> CounterBitmap;
size_t TotalBits() { // Slow. Call it only for printing stats.
size_t Res = 0;
for (auto x : CounterBitmap) Res += __builtin_popcount(x);
return Res;
}
UserCallback Callback;
FuzzingOptions Options;
system_clock::time_point ProcessStartTime = system_clock::now();
static system_clock::time_point UnitStartTime;
};
}; // namespace fuzzer