llvm-project/llvm/lib/Fuzzer/FuzzerLoop.cpp

340 lines
10 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>
namespace fuzzer {
// Only one Fuzzer per process.
static Fuzzer *F;
Fuzzer::Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options)
: USF(USF), Options(Options) {
SetDeathCallback();
InitializeTraceState();
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);
Printf("%s%s", T.data(), PrintAfter);
}
}
void Fuzzer::StaticDeathCallback() {
assert(F);
F->DeathCallback();
}
void Fuzzer::DeathCallback() {
Printf("DEATH:\n");
Print(CurrentUnit, "\n");
PrintUnitInASCIIOrTokens(CurrentUnit, "\n");
WriteToCrash(CurrentUnit, "crash-");
}
void Fuzzer::StaticAlarmCallback() {
assert(F);
F->AlarmCallback();
}
void Fuzzer::AlarmCallback() {
assert(Options.UnitTimeoutSec > 0);
size_t Seconds =
duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
if (Seconds == 0) return;
if (Options.Verbosity >= 2)
Printf("AlarmCallback %zd\n", Seconds);
if (Seconds >= (size_t)Options.UnitTimeoutSec) {
Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
Printf(" and the timeout value is %d (use -timeout=N to change)\n",
Options.UnitTimeoutSec);
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);
Printf("#%zd\t%s cov %zd bits %zd units %zd exec/s %zd %s", TotalNumberOfRuns,
Where, Cov, TotalBits(), Corpus.size(), ExecPerSec, End);
}
void Fuzzer::RereadOutputCorpus() {
if (Options.OutputCorpus.empty()) return;
std::vector<Unit> AdditionalCorpus;
ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
&EpochOfLastReadOfOutputCorpus);
if (Corpus.empty()) {
Corpus = AdditionalCorpus;
return;
}
if (!Options.Reload) return;
if (Options.Verbosity >= 2)
Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
for (auto &X : AdditionalCorpus) {
if (X.size() > (size_t)Options.MaxLen)
X.resize(Options.MaxLen);
if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
CurrentUnit.clear();
CurrentUnit.insert(CurrentUnit.begin(), X.begin(), X.end());
size_t NewCoverage = RunOne(CurrentUnit);
if (NewCoverage) {
Corpus.push_back(X);
if (Options.Verbosity >= 1)
PrintStats("RELOAD", NewCoverage);
}
}
}
}
void Fuzzer::ShuffleAndMinimize() {
size_t MaxCov = 0;
bool PreferSmall =
(Options.PreferSmallDuringInitialShuffle == 1 ||
(Options.PreferSmallDuringInitialShuffle == -1 && rand() % 2));
if (Options.Verbosity)
Printf("PreferSmall: %d\n", PreferSmall);
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)
Printf("NEW0: %zd L %zd\n", NewCoverage, U.size());
}
}
}
Corpus = NewCorpus;
for (auto &X : Corpus)
UnitHashesAddedToCorpus.insert(Hash(X));
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
Res = RunOneMaximizeTotalCoverage(U);
auto UnitStopTime = system_clock::now();
auto TimeOfUnit =
duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
if (TimeOfUnit > TimeOfLongestUnitInSeconds) {
TimeOfLongestUnitInSeconds = TimeOfUnit;
Printf("Longest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
Print(U, "\n");
}
return Res;
}
void Fuzzer::RunOneAndUpdateCorpus(const Unit &U) {
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
return;
ReportNewCoverage(RunOne(U), U);
}
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()) {
USF.TargetFunction(U.data(), U.size());
} else {
auto T = SubstituteTokens(U);
USF.TargetFunction(T.data(), T.size());
}
}
// 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)
Printf("Written to %s\n", Path.c_str());
}
void Fuzzer::WriteToCrash(const Unit &U, const char *Prefix) {
std::string Path = Prefix + Hash(U);
WriteToFile(U, Path);
Printf("CRASHED; file written to %s\nBase64: ", Path.c_str());
PrintFileAsBase64(Path);
}
void Fuzzer::SaveCorpus() {
if (Options.OutputCorpus.empty()) return;
for (const auto &U : Corpus)
WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
if (Options.Verbosity)
Printf("Written corpus of %zd files to %s\n", Corpus.size(),
Options.OutputCorpus.c_str());
}
void Fuzzer::ReportNewCoverage(size_t NewCoverage, const Unit &U) {
if (!NewCoverage) return;
Corpus.push_back(U);
UnitHashesAddedToCorpus.insert(Hash(U));
PrintStats("NEW ", NewCoverage, "");
if (Options.Verbosity) {
Printf(" L: %zd", U.size());
if (U.size() < 30) {
Printf(" ");
PrintUnitInASCIIOrTokens(U, "\t");
Print(U);
}
Printf("\n");
}
WriteToOutputCorpus(U);
if (Options.ExitOnFirst)
exit(0);
}
void Fuzzer::MutateAndTestOne(Unit *U) {
for (int i = 0; i < Options.MutateDepth; i++) {
StartTraceRecording();
size_t Size = U->size();
U->resize(Options.MaxLen);
size_t NewSize = USF.Mutate(U->data(), Size, U->size());
assert(NewSize > 0 && NewSize <= (size_t)Options.MaxLen);
U->resize(NewSize);
RunOneAndUpdateCorpus(*U);
size_t NumTraceBasedMutations = StopTraceRecording();
for (size_t j = 0; j < NumTraceBasedMutations; j++) {
ApplyTraceBasedMutation(j, U);
RunOneAndUpdateCorpus(*U);
}
}
}
void Fuzzer::Loop(size_t NumIterations) {
for (size_t i = 1; i <= NumIterations; i++) {
for (size_t J1 = 0; J1 < Corpus.size(); J1++) {
SyncCorpus();
RereadOutputCorpus();
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
return;
// First, simply mutate the unit w/o doing crosses.
CurrentUnit = Corpus[J1];
MutateAndTestOne(&CurrentUnit);
// Now, cross with others.
if (Options.DoCrossOver && !Corpus[J1].empty()) {
for (size_t J2 = 0; J2 < Corpus.size(); J2++) {
CurrentUnit.resize(Options.MaxLen);
size_t NewSize = USF.CrossOver(
Corpus[J1].data(), Corpus[J1].size(), Corpus[J2].data(),
Corpus[J2].size(), CurrentUnit.data(), CurrentUnit.size());
assert(NewSize > 0 && NewSize <= (size_t)Options.MaxLen);
CurrentUnit.resize(NewSize);
MutateAndTestOne(&CurrentUnit);
}
}
}
}
}
void Fuzzer::SyncCorpus() {
if (Options.SyncCommand.empty() || Options.OutputCorpus.empty()) return;
auto Now = system_clock::now();
if (duration_cast<seconds>(Now - LastExternalSync).count() <
Options.SyncTimeout)
return;
LastExternalSync = Now;
ExecuteCommand(Options.SyncCommand + " " + Options.OutputCorpus);
}
} // namespace fuzzer