llvm-6502/lib/Fuzzer/FuzzerLoop.cpp
2015-03-31 20:13:20 +00:00

312 lines
9.0 KiB
C++

//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Fuzzer's main loop.
//===----------------------------------------------------------------------===//
#include "FuzzerInternal.h"
#include <sanitizer/coverage_interface.h>
#include <algorithm>
#include <iostream>
namespace fuzzer {
// Only one Fuzzer per process.
static Fuzzer *F;
Fuzzer::Fuzzer(UserCallback Callback, FuzzingOptions Options)
: Callback(Callback), Options(Options) {
SetDeathCallback();
InitializeDFSan();
assert(!F);
F = this;
}
void Fuzzer::SetDeathCallback() {
__sanitizer_set_death_callback(StaticDeathCallback);
}
void Fuzzer::PrintUnitInASCIIOrTokens(const Unit &U, const char *PrintAfter) {
if (Options.Tokens.empty()) {
PrintASCII(U, PrintAfter);
} else {
auto T = SubstituteTokens(U);
T.push_back(0);
std::cerr << T.data();
std::cerr << PrintAfter;
}
}
void Fuzzer::StaticDeathCallback() {
assert(F);
F->DeathCallback();
}
void Fuzzer::DeathCallback() {
std::cerr << "DEATH: " << std::endl;
Print(CurrentUnit, "\n");
PrintUnitInASCIIOrTokens(CurrentUnit, "\n");
WriteToCrash(CurrentUnit, "crash-");
}
void Fuzzer::StaticAlarmCallback() {
assert(F);
F->AlarmCallback();
}
void Fuzzer::AlarmCallback() {
size_t Seconds =
duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
std::cerr << "ALARM: working on the last Unit for " << Seconds << " seconds"
<< std::endl;
if (Seconds >= 3) {
Print(CurrentUnit, "\n");
PrintUnitInASCIIOrTokens(CurrentUnit, "\n");
WriteToCrash(CurrentUnit, "timeout-");
}
exit(1);
}
void Fuzzer::PrintStats(const char *Where, size_t Cov, const char *End) {
if (!Options.Verbosity) return;
size_t Seconds = secondsSinceProcessStartUp();
size_t ExecPerSec = (Seconds ? TotalNumberOfRuns / Seconds : 0);
std::cerr
<< "#" << TotalNumberOfRuns
<< "\t" << Where
<< " cov " << Cov
<< " bits " << TotalBits()
<< " units " << Corpus.size()
<< " exec/s " << ExecPerSec
<< End;
}
void Fuzzer::ShuffleAndMinimize() {
size_t MaxCov = 0;
bool PreferSmall =
(Options.PreferSmallDuringInitialShuffle == 1 ||
(Options.PreferSmallDuringInitialShuffle == -1 && rand() % 2));
if (Options.Verbosity)
std::cerr << "PreferSmall: " << PreferSmall << "\n";
PrintStats("READ ", 0);
std::vector<Unit> NewCorpus;
std::random_shuffle(Corpus.begin(), Corpus.end());
if (PreferSmall)
std::stable_sort(
Corpus.begin(), Corpus.end(),
[](const Unit &A, const Unit &B) { return A.size() < B.size(); });
Unit &U = CurrentUnit;
for (const auto &C : Corpus) {
for (size_t First = 0; First < 1; First++) {
U.clear();
size_t Last = std::min(First + Options.MaxLen, C.size());
U.insert(U.begin(), C.begin() + First, C.begin() + Last);
size_t NewCoverage = RunOne(U);
if (NewCoverage) {
MaxCov = NewCoverage;
NewCorpus.push_back(U);
if (Options.Verbosity >= 2)
std::cerr << "NEW0: " << NewCoverage
<< " L " << U.size()
<< "\n";
}
}
}
Corpus = NewCorpus;
PrintStats("INITED", MaxCov);
}
size_t Fuzzer::RunOne(const Unit &U) {
UnitStartTime = system_clock::now();
TotalNumberOfRuns++;
size_t Res = 0;
if (Options.UseFullCoverageSet)
Res = RunOneMaximizeFullCoverageSet(U);
else if (Options.UseCoveragePairs)
Res = RunOneMaximizeCoveragePairs(U);
else
Res = RunOneMaximizeTotalCoverage(U);
auto UnitStopTime = system_clock::now();
auto TimeOfUnit =
duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
if (TimeOfUnit > TimeOfLongestUnitInSeconds) {
TimeOfLongestUnitInSeconds = TimeOfUnit;
std::cerr << "Longest unit: " << TimeOfLongestUnitInSeconds
<< " s:\n";
Print(U, "\n");
}
return Res;
}
static uintptr_t HashOfArrayOfPCs(uintptr_t *PCs, uintptr_t NumPCs) {
uintptr_t Res = 0;
for (uintptr_t i = 0; i < NumPCs; i++) {
Res = (Res + PCs[i]) * 7;
}
return Res;
}
Unit Fuzzer::SubstituteTokens(const Unit &U) const {
Unit Res;
for (auto Idx : U) {
if (Idx < Options.Tokens.size()) {
std::string Token = Options.Tokens[Idx];
Res.insert(Res.end(), Token.begin(), Token.end());
} else {
Res.push_back(' ');
}
}
// FIXME: Apply DFSan labels.
return Res;
}
void Fuzzer::ExecuteCallback(const Unit &U) {
if (Options.Tokens.empty()) {
Callback(U.data(), U.size());
} else {
auto T = SubstituteTokens(U);
Callback(T.data(), T.size());
}
}
// Experimental. Does not yet scale.
// Fuly reset the current coverage state, run a single unit,
// collect all coverage pairs and return non-zero if a new pair is observed.
size_t Fuzzer::RunOneMaximizeCoveragePairs(const Unit &U) {
__sanitizer_reset_coverage();
ExecuteCallback(U);
uintptr_t *PCs;
uintptr_t NumPCs = __sanitizer_get_coverage_guards(&PCs);
bool HasNewPairs = false;
for (uintptr_t i = 0; i < NumPCs; i++) {
if (!PCs[i]) continue;
for (uintptr_t j = 0; j < NumPCs; j++) {
if (!PCs[j]) continue;
uint64_t Pair = (i << 32) | j;
HasNewPairs |= CoveragePairs.insert(Pair).second;
}
}
if (HasNewPairs)
return CoveragePairs.size();
return 0;
}
// Experimental.
// Fuly reset the current coverage state, run a single unit,
// compute a hash function from the full coverage set,
// return non-zero if the hash value is new.
// This produces tons of new units and as is it's only suitable for small tests,
// e.g. test/FullCoverageSetTest.cpp. FIXME: make it scale.
size_t Fuzzer::RunOneMaximizeFullCoverageSet(const Unit &U) {
__sanitizer_reset_coverage();
ExecuteCallback(U);
uintptr_t *PCs;
uintptr_t NumPCs =__sanitizer_get_coverage_guards(&PCs);
if (FullCoverageSets.insert(HashOfArrayOfPCs(PCs, NumPCs)).second)
return FullCoverageSets.size();
return 0;
}
size_t Fuzzer::RunOneMaximizeTotalCoverage(const Unit &U) {
size_t NumCounters = __sanitizer_get_number_of_counters();
if (Options.UseCounters) {
CounterBitmap.resize(NumCounters);
__sanitizer_update_counter_bitset_and_clear_counters(0);
}
size_t OldCoverage = __sanitizer_get_total_unique_coverage();
ExecuteCallback(U);
size_t NewCoverage = __sanitizer_get_total_unique_coverage();
size_t NumNewBits = 0;
if (Options.UseCounters)
NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
CounterBitmap.data());
if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) && Options.Verbosity)
PrintStats("pulse ", NewCoverage);
if (NewCoverage > OldCoverage || NumNewBits)
return NewCoverage;
return 0;
}
void Fuzzer::WriteToOutputCorpus(const Unit &U) {
if (Options.OutputCorpus.empty()) return;
std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
WriteToFile(U, Path);
if (Options.Verbosity >= 2)
std::cerr << "Written to " << Path << std::endl;
}
void Fuzzer::WriteToCrash(const Unit &U, const char *Prefix) {
std::string Path = Prefix + Hash(U);
WriteToFile(U, Path);
std::cerr << "CRASHED; file written to " << Path << std::endl;
}
void Fuzzer::SaveCorpus() {
if (Options.OutputCorpus.empty()) return;
for (const auto &U : Corpus)
WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
if (Options.Verbosity)
std::cerr << "Written corpus of " << Corpus.size() << " files to "
<< Options.OutputCorpus << "\n";
}
size_t Fuzzer::MutateAndTestOne(Unit *U) {
size_t NewUnits = 0;
for (int i = 0; i < Options.MutateDepth; i++) {
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
return NewUnits;
MutateWithDFSan(U);
Mutate(U, Options.MaxLen);
size_t NewCoverage = RunOne(*U);
if (NewCoverage) {
Corpus.push_back(*U);
NewUnits++;
PrintStats("NEW ", NewCoverage, "");
if (Options.Verbosity) {
std::cerr << " L: " << U->size();
if (U->size() < 30) {
std::cerr << " ";
PrintUnitInASCIIOrTokens(*U, "\t");
Print(*U);
}
std::cerr << "\n";
}
WriteToOutputCorpus(*U);
if (Options.ExitOnFirst)
exit(0);
}
}
return NewUnits;
}
size_t Fuzzer::Loop(size_t NumIterations) {
size_t NewUnits = 0;
for (size_t i = 1; i <= NumIterations; i++) {
for (size_t J1 = 0; J1 < Corpus.size(); J1++) {
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
return NewUnits;
// First, simply mutate the unit w/o doing crosses.
CurrentUnit = Corpus[J1];
NewUnits += MutateAndTestOne(&CurrentUnit);
// Now, cross with others.
if (Options.DoCrossOver) {
for (size_t J2 = 0; J2 < Corpus.size(); J2++) {
CurrentUnit.clear();
CrossOver(Corpus[J1], Corpus[J2], &CurrentUnit, Options.MaxLen);
NewUnits += MutateAndTestOne(&CurrentUnit);
}
}
}
}
return NewUnits;
}
} // namespace fuzzer