1 //===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
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 //===----------------------------------------------------------------------===//
10 //===----------------------------------------------------------------------===//
12 #include "FuzzerCorpus.h"
14 #include "FuzzerInternal.h"
15 #include "FuzzerMutate.h"
16 #include "FuzzerRandom.h"
17 #include "FuzzerShmem.h"
18 #include "FuzzerTracePC.h"
25 #if defined(__has_include)
26 #if __has_include(<sanitizer / lsan_interface.h>)
27 #include <sanitizer/lsan_interface.h>
31 #define NO_SANITIZE_MEMORY
32 #if defined(__has_feature)
33 #if __has_feature(memory_sanitizer)
34 #undef NO_SANITIZE_MEMORY
35 #define NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
40 static const size_t kMaxUnitSizeToPrint = 256;
42 thread_local bool Fuzzer::IsMyThread;
44 SharedMemoryRegion SMR;
46 bool RunningUserCallback = false;
48 // Only one Fuzzer per process.
51 // Leak detection is expensive, so we first check if there were more mallocs
52 // than frees (using the sanitizer malloc hooks) and only then try to call lsan.
53 struct MallocFreeTracer {
54 void Start(int TraceLevel) {
55 this->TraceLevel = TraceLevel;
57 Printf("MallocFreeTracer: START\n");
61 // Returns true if there were more mallocs than frees.
64 Printf("MallocFreeTracer: STOP %zd %zd (%s)\n", Mallocs.load(),
65 Frees.load(), Mallocs == Frees ? "same" : "DIFFERENT");
66 bool Result = Mallocs > Frees;
72 std::atomic<size_t> Mallocs;
73 std::atomic<size_t> Frees;
76 std::recursive_mutex TraceMutex;
77 bool TraceDisabled = false;
80 static MallocFreeTracer AllocTracer;
82 // Locks printing and avoids nested hooks triggered from mallocs/frees in
86 TraceLock() : Lock(AllocTracer.TraceMutex) {
87 AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled;
89 ~TraceLock() { AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled; }
91 bool IsDisabled() const {
92 // This is already inverted value.
93 return !AllocTracer.TraceDisabled;
97 std::lock_guard<std::recursive_mutex> Lock;
100 ATTRIBUTE_NO_SANITIZE_MEMORY
101 void MallocHook(const volatile void *ptr, size_t size) {
102 size_t N = AllocTracer.Mallocs++;
103 F->HandleMalloc(size);
104 if (int TraceLevel = AllocTracer.TraceLevel) {
106 if (Lock.IsDisabled())
108 Printf("MALLOC[%zd] %p %zd\n", N, ptr, size);
109 if (TraceLevel >= 2 && EF)
114 ATTRIBUTE_NO_SANITIZE_MEMORY
115 void FreeHook(const volatile void *ptr) {
116 size_t N = AllocTracer.Frees++;
117 if (int TraceLevel = AllocTracer.TraceLevel) {
119 if (Lock.IsDisabled())
121 Printf("FREE[%zd] %p\n", N, ptr);
122 if (TraceLevel >= 2 && EF)
127 // Crash on a single malloc that exceeds the rss limit.
128 void Fuzzer::HandleMalloc(size_t Size) {
129 if (!Options.MallocLimitMb || (Size >> 20) < (size_t)Options.MallocLimitMb)
131 Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n", GetPid(),
133 Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
135 DumpCurrentUnit("oom-");
136 Printf("SUMMARY: libFuzzer: out-of-memory\n");
138 _Exit(Options.ErrorExitCode); // Stop right now.
141 Fuzzer::Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
142 FuzzingOptions Options)
143 : CB(CB), Corpus(Corpus), MD(MD), Options(Options) {
144 if (EF->__sanitizer_set_death_callback)
145 EF->__sanitizer_set_death_callback(StaticDeathCallback);
150 if (Options.DetectLeaks && EF->__sanitizer_install_malloc_and_free_hooks)
151 EF->__sanitizer_install_malloc_and_free_hooks(MallocHook, FreeHook);
152 TPC.SetUseCounters(Options.UseCounters);
153 TPC.SetUseValueProfileMask(Options.UseValueProfile);
155 if (Options.Verbosity)
156 TPC.PrintModuleInfo();
157 if (!Options.OutputCorpus.empty() && Options.ReloadIntervalSec)
158 EpochOfLastReadOfOutputCorpus = GetEpoch(Options.OutputCorpus);
159 MaxInputLen = MaxMutationLen = Options.MaxLen;
160 TmpMaxMutationLen = Max(size_t(4), Corpus.MaxInputSize());
161 AllocateCurrentUnitData();
163 memset(BaseSha1, 0, sizeof(BaseSha1));
164 TPC.SetFocusFunction(Options.FocusFunction);
165 DFT.Init(Options.DataFlowTrace, Options.FocusFunction);
170 void Fuzzer::AllocateCurrentUnitData() {
171 if (CurrentUnitData || MaxInputLen == 0)
173 CurrentUnitData = new uint8_t[MaxInputLen];
176 void Fuzzer::StaticDeathCallback() {
181 void Fuzzer::DumpCurrentUnit(const char *Prefix) {
182 if (!CurrentUnitData)
183 return; // Happens when running individual inputs.
184 ScopedDisableMsanInterceptorChecks S;
185 MD.PrintMutationSequence();
186 Printf("; base unit: %s\n", Sha1ToString(BaseSha1).c_str());
187 size_t UnitSize = CurrentUnitSize;
188 if (UnitSize <= kMaxUnitSizeToPrint) {
189 PrintHexArray(CurrentUnitData, UnitSize, "\n");
190 PrintASCII(CurrentUnitData, UnitSize, "\n");
192 WriteUnitToFileWithPrefix({CurrentUnitData, CurrentUnitData + UnitSize},
197 void Fuzzer::DeathCallback() {
198 DumpCurrentUnit("crash-");
202 void Fuzzer::StaticAlarmCallback() {
207 void Fuzzer::StaticCrashSignalCallback() {
212 void Fuzzer::StaticExitCallback() {
217 void Fuzzer::StaticInterruptCallback() {
219 F->InterruptCallback();
222 void Fuzzer::StaticGracefulExitCallback() {
224 F->GracefulExitRequested = true;
225 Printf("INFO: signal received, trying to exit gracefully\n");
228 void Fuzzer::StaticFileSizeExceedCallback() {
229 Printf("==%lu== ERROR: libFuzzer: file size exceeded\n", GetPid());
233 void Fuzzer::CrashCallback() {
234 if (EF->__sanitizer_acquire_crash_state)
235 EF->__sanitizer_acquire_crash_state();
236 Printf("==%lu== ERROR: libFuzzer: deadly signal\n", GetPid());
238 Printf("NOTE: libFuzzer has rudimentary signal handlers.\n"
239 " Combine libFuzzer with AddressSanitizer or similar for better "
241 Printf("SUMMARY: libFuzzer: deadly signal\n");
242 DumpCurrentUnit("crash-");
244 _Exit(Options.ErrorExitCode); // Stop right now.
247 void Fuzzer::ExitCallback() {
248 if (!RunningUserCallback)
249 return; // This exit did not come from the user callback
250 if (EF->__sanitizer_acquire_crash_state &&
251 !EF->__sanitizer_acquire_crash_state())
253 Printf("==%lu== ERROR: libFuzzer: fuzz target exited\n", GetPid());
255 Printf("SUMMARY: libFuzzer: fuzz target exited\n");
256 DumpCurrentUnit("crash-");
258 _Exit(Options.ErrorExitCode);
261 void Fuzzer::MaybeExitGracefully() {
262 if (!GracefulExitRequested) return;
263 Printf("==%lu== INFO: libFuzzer: exiting as requested\n", GetPid());
268 void Fuzzer::InterruptCallback() {
269 Printf("==%lu== libFuzzer: run interrupted; exiting\n", GetPid());
271 _Exit(0); // Stop right now, don't perform any at-exit actions.
275 void Fuzzer::AlarmCallback() {
276 assert(Options.UnitTimeoutSec > 0);
277 // In Windows Alarm callback is executed by a different thread.
278 #if !LIBFUZZER_WINDOWS
279 if (!InFuzzingThread())
282 if (!RunningUserCallback)
283 return; // We have not started running units yet.
285 duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
288 if (Options.Verbosity >= 2)
289 Printf("AlarmCallback %zd\n", Seconds);
290 if (Seconds >= (size_t)Options.UnitTimeoutSec) {
291 if (EF->__sanitizer_acquire_crash_state &&
292 !EF->__sanitizer_acquire_crash_state())
294 Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
295 Printf(" and the timeout value is %d (use -timeout=N to change)\n",
296 Options.UnitTimeoutSec);
297 DumpCurrentUnit("timeout-");
298 Printf("==%lu== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
301 Printf("SUMMARY: libFuzzer: timeout\n");
303 _Exit(Options.TimeoutExitCode); // Stop right now.
307 void Fuzzer::RssLimitCallback() {
308 if (EF->__sanitizer_acquire_crash_state &&
309 !EF->__sanitizer_acquire_crash_state())
312 "==%lu== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
313 GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
314 Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
315 PrintMemoryProfile();
316 DumpCurrentUnit("oom-");
317 Printf("SUMMARY: libFuzzer: out-of-memory\n");
319 _Exit(Options.ErrorExitCode); // Stop right now.
322 void Fuzzer::PrintStats(const char *Where, const char *End, size_t Units) {
323 size_t ExecPerSec = execPerSec();
324 if (!Options.Verbosity)
326 Printf("#%zd\t%s", TotalNumberOfRuns, Where);
327 if (size_t N = TPC.GetTotalPCCoverage())
328 Printf(" cov: %zd", N);
329 if (size_t N = Corpus.NumFeatures())
330 Printf(" ft: %zd", N);
331 if (!Corpus.empty()) {
332 Printf(" corp: %zd", Corpus.NumActiveUnits());
333 if (size_t N = Corpus.SizeInBytes()) {
336 else if (N < (1 << 24))
337 Printf("/%zdKb", N >> 10);
339 Printf("/%zdMb", N >> 20);
341 if (size_t FF = Corpus.NumInputsThatTouchFocusFunction())
342 Printf(" focus: %zd", FF);
344 if (TmpMaxMutationLen)
345 Printf(" lim: %zd", TmpMaxMutationLen);
347 Printf(" units: %zd", Units);
349 Printf(" exec/s: %zd", ExecPerSec);
350 Printf(" rss: %zdMb", GetPeakRSSMb());
354 void Fuzzer::PrintFinalStats() {
355 if (Options.PrintCoverage)
357 if (Options.PrintUnstableStats)
358 TPC.PrintUnstableStats();
359 if (Options.DumpCoverage)
361 if (Options.PrintCorpusStats)
363 if (Options.PrintMutationStats) MD.PrintMutationStats();
364 if (!Options.PrintFinalStats)
366 size_t ExecPerSec = execPerSec();
367 Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
368 Printf("stat::average_exec_per_sec: %zd\n", ExecPerSec);
369 Printf("stat::new_units_added: %zd\n", NumberOfNewUnitsAdded);
370 Printf("stat::slowest_unit_time_sec: %zd\n", TimeOfLongestUnitInSeconds);
371 Printf("stat::peak_rss_mb: %zd\n", GetPeakRSSMb());
374 void Fuzzer::SetMaxInputLen(size_t MaxInputLen) {
375 assert(this->MaxInputLen == 0); // Can only reset MaxInputLen from 0 to non-0.
377 this->MaxInputLen = MaxInputLen;
378 this->MaxMutationLen = MaxInputLen;
379 AllocateCurrentUnitData();
380 Printf("INFO: -max_len is not provided; "
381 "libFuzzer will not generate inputs larger than %zd bytes\n",
385 void Fuzzer::SetMaxMutationLen(size_t MaxMutationLen) {
386 assert(MaxMutationLen && MaxMutationLen <= MaxInputLen);
387 this->MaxMutationLen = MaxMutationLen;
390 void Fuzzer::CheckExitOnSrcPosOrItem() {
391 if (!Options.ExitOnSrcPos.empty()) {
392 static auto *PCsSet = new Set<uintptr_t>;
393 auto HandlePC = [&](uintptr_t PC) {
394 if (!PCsSet->insert(PC).second)
396 std::string Descr = DescribePC("%F %L", PC + 1);
397 if (Descr.find(Options.ExitOnSrcPos) != std::string::npos) {
398 Printf("INFO: found line matching '%s', exiting.\n",
399 Options.ExitOnSrcPos.c_str());
403 TPC.ForEachObservedPC(HandlePC);
405 if (!Options.ExitOnItem.empty()) {
406 if (Corpus.HasUnit(Options.ExitOnItem)) {
407 Printf("INFO: found item with checksum '%s', exiting.\n",
408 Options.ExitOnItem.c_str());
414 void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
415 if (Options.OutputCorpus.empty() || !Options.ReloadIntervalSec)
417 Vector<Unit> AdditionalCorpus;
418 ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
419 &EpochOfLastReadOfOutputCorpus, MaxSize,
420 /*ExitOnError*/ false);
421 if (Options.Verbosity >= 2)
422 Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
423 bool Reloaded = false;
424 for (auto &U : AdditionalCorpus) {
425 if (U.size() > MaxSize)
427 if (!Corpus.HasUnit(U)) {
428 if (RunOne(U.data(), U.size())) {
429 CheckExitOnSrcPosOrItem();
435 PrintStats("RELOAD");
438 void Fuzzer::PrintPulseAndReportSlowInput(const uint8_t *Data, size_t Size) {
440 duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
441 if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
442 secondsSinceProcessStartUp() >= 2)
443 PrintStats("pulse ");
444 if (TimeOfUnit > TimeOfLongestUnitInSeconds * 1.1 &&
445 TimeOfUnit >= Options.ReportSlowUnits) {
446 TimeOfLongestUnitInSeconds = TimeOfUnit;
447 Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
448 WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
452 void Fuzzer::CheckForUnstableCounters(const uint8_t *Data, size_t Size) {
453 auto CBSetupAndRun = [&]() {
454 ScopedEnableMsanInterceptorChecks S;
455 UnitStartTime = system_clock::now();
457 RunningUserCallback = true;
459 RunningUserCallback = false;
460 UnitStopTime = system_clock::now();
463 // Copy original run counters into our unstable counters
464 TPC.InitializeUnstableCounters();
468 TPC.UpdateUnstableCounters(Options.HandleUnstable);
472 TPC.UpdateUnstableCounters(Options.HandleUnstable);
474 // Move minimum hit counts back to ModuleInline8bitCounters
475 if (Options.HandleUnstable == TracePC::MinUnstable ||
476 Options.HandleUnstable == TracePC::ZeroUnstable)
477 TPC.ApplyUnstableCounters();
480 bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
481 InputInfo *II, bool *FoundUniqFeatures) {
485 ExecuteCallback(Data, Size);
487 UniqFeatureSetTmp.clear();
488 size_t FoundUniqFeaturesOfII = 0;
489 size_t NumUpdatesBefore = Corpus.NumFeatureUpdates();
490 bool NewFeaturesUnstable = false;
492 if (Options.HandleUnstable || Options.PrintUnstableStats) {
493 TPC.CollectFeatures([&](size_t Feature) {
494 if (Corpus.IsFeatureNew(Feature, Size, Options.Shrink))
495 NewFeaturesUnstable = true;
497 if (NewFeaturesUnstable)
498 CheckForUnstableCounters(Data, Size);
501 TPC.CollectFeatures([&](size_t Feature) {
502 if (Corpus.AddFeature(Feature, Size, Options.Shrink))
503 UniqFeatureSetTmp.push_back(Feature);
504 if (Options.ReduceInputs && II)
505 if (std::binary_search(II->UniqFeatureSet.begin(),
506 II->UniqFeatureSet.end(), Feature))
507 FoundUniqFeaturesOfII++;
510 if (FoundUniqFeatures)
511 *FoundUniqFeatures = FoundUniqFeaturesOfII;
512 PrintPulseAndReportSlowInput(Data, Size);
513 size_t NumNewFeatures = Corpus.NumFeatureUpdates() - NumUpdatesBefore;
515 if (NumNewFeatures) {
516 TPC.UpdateObservedPCs();
517 Corpus.AddToCorpus({Data, Data + Size}, NumNewFeatures, MayDeleteFile,
518 TPC.ObservedFocusFunction(), UniqFeatureSetTmp, DFT, II);
521 if (II && FoundUniqFeaturesOfII &&
522 II->DataFlowTraceForFocusFunction.empty() &&
523 FoundUniqFeaturesOfII == II->UniqFeatureSet.size() &&
524 II->U.size() > Size) {
525 Corpus.Replace(II, {Data, Data + Size});
531 size_t Fuzzer::GetCurrentUnitInFuzzingThead(const uint8_t **Data) const {
532 assert(InFuzzingThread());
533 *Data = CurrentUnitData;
534 return CurrentUnitSize;
537 void Fuzzer::CrashOnOverwrittenData() {
538 Printf("==%d== ERROR: libFuzzer: fuzz target overwrites it's const input\n",
540 DumpCurrentUnit("crash-");
541 Printf("SUMMARY: libFuzzer: out-of-memory\n");
542 _Exit(Options.ErrorExitCode); // Stop right now.
545 // Compare two arrays, but not all bytes if the arrays are large.
546 static bool LooseMemeq(const uint8_t *A, const uint8_t *B, size_t Size) {
547 const size_t Limit = 64;
549 return !memcmp(A, B, Size);
550 // Compare first and last Limit/2 bytes.
551 return !memcmp(A, B, Limit / 2) &&
552 !memcmp(A + Size - Limit / 2, B + Size - Limit / 2, Limit / 2);
555 void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
556 TPC.RecordInitialStack();
558 assert(InFuzzingThread());
560 SMR.WriteByteArray(Data, Size);
561 // We copy the contents of Unit into a separate heap buffer
562 // so that we reliably find buffer overflows in it.
563 uint8_t *DataCopy = new uint8_t[Size];
564 memcpy(DataCopy, Data, Size);
565 if (EF->__msan_unpoison)
566 EF->__msan_unpoison(DataCopy, Size);
567 if (CurrentUnitData && CurrentUnitData != Data)
568 memcpy(CurrentUnitData, Data, Size);
569 CurrentUnitSize = Size;
571 ScopedEnableMsanInterceptorChecks S;
572 AllocTracer.Start(Options.TraceMalloc);
573 UnitStartTime = system_clock::now();
575 RunningUserCallback = true;
576 int Res = CB(DataCopy, Size);
577 RunningUserCallback = false;
578 UnitStopTime = system_clock::now();
581 HasMoreMallocsThanFrees = AllocTracer.Stop();
583 if (!LooseMemeq(DataCopy, Data, Size))
584 CrashOnOverwrittenData();
589 void Fuzzer::WriteToOutputCorpus(const Unit &U) {
590 if (Options.OnlyASCII)
592 if (Options.OutputCorpus.empty())
594 std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
595 WriteToFile(U, Path);
596 if (Options.Verbosity >= 2)
597 Printf("Written %zd bytes to %s\n", U.size(), Path.c_str());
600 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
601 if (!Options.SaveArtifacts)
603 std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
604 if (!Options.ExactArtifactPath.empty())
605 Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
606 WriteToFile(U, Path);
607 Printf("artifact_prefix='%s'; Test unit written to %s\n",
608 Options.ArtifactPrefix.c_str(), Path.c_str());
609 if (U.size() <= kMaxUnitSizeToPrint)
610 Printf("Base64: %s\n", Base64(U).c_str());
613 void Fuzzer::PrintStatusForNewUnit(const Unit &U, const char *Text) {
614 if (!Options.PrintNEW)
616 PrintStats(Text, "");
617 if (Options.Verbosity) {
618 Printf(" L: %zd/%zd ", U.size(), Corpus.MaxInputSize());
619 MD.PrintMutationSequence();
624 void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
625 II->NumSuccessfullMutations++;
626 MD.RecordSuccessfulMutationSequence();
627 PrintStatusForNewUnit(U, II->Reduced ? "REDUCE" : "NEW ");
628 WriteToOutputCorpus(U);
629 NumberOfNewUnitsAdded++;
630 CheckExitOnSrcPosOrItem(); // Check only after the unit is saved to corpus.
631 LastCorpusUpdateRun = TotalNumberOfRuns;
634 // Tries detecting a memory leak on the particular input that we have just
635 // executed before calling this function.
636 void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
637 bool DuringInitialCorpusExecution) {
638 if (!HasMoreMallocsThanFrees)
639 return; // mallocs==frees, a leak is unlikely.
640 if (!Options.DetectLeaks)
642 if (!DuringInitialCorpusExecution &&
643 TotalNumberOfRuns >= Options.MaxNumberOfRuns)
645 if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
646 !(EF->__lsan_do_recoverable_leak_check))
648 // Run the target once again, but with lsan disabled so that if there is
649 // a real leak we do not report it twice.
650 EF->__lsan_disable();
651 ExecuteCallback(Data, Size);
653 if (!HasMoreMallocsThanFrees)
654 return; // a leak is unlikely.
655 if (NumberOfLeakDetectionAttempts++ > 1000) {
656 Options.DetectLeaks = false;
657 Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
658 " Most likely the target function accumulates allocated\n"
659 " memory in a global state w/o actually leaking it.\n"
660 " You may try running this binary with -trace_malloc=[12]"
661 " to get a trace of mallocs and frees.\n"
662 " If LeakSanitizer is enabled in this process it will still\n"
663 " run on the process shutdown.\n");
666 // Now perform the actual lsan pass. This is expensive and we must ensure
667 // we don't call it too often.
668 if (EF->__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
669 if (DuringInitialCorpusExecution)
670 Printf("\nINFO: a leak has been found in the initial corpus.\n\n");
671 Printf("INFO: to ignore leaks on libFuzzer side use -detect_leaks=0.\n\n");
672 CurrentUnitSize = Size;
673 DumpCurrentUnit("leak-");
675 _Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
679 void Fuzzer::MutateAndTestOne() {
680 MD.StartMutationSequence();
682 auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
683 const auto &U = II.U;
684 memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
685 assert(CurrentUnitData);
686 size_t Size = U.size();
687 assert(Size <= MaxInputLen && "Oversized Unit");
688 memcpy(CurrentUnitData, U.data(), Size);
690 assert(MaxMutationLen > 0);
692 size_t CurrentMaxMutationLen =
693 Min(MaxMutationLen, Max(U.size(), TmpMaxMutationLen));
694 assert(CurrentMaxMutationLen > 0);
696 for (int i = 0; i < Options.MutateDepth; i++) {
697 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
699 MaybeExitGracefully();
701 if (II.HasFocusFunction && !II.DataFlowTraceForFocusFunction.empty() &&
702 Size <= CurrentMaxMutationLen)
703 NewSize = MD.MutateWithMask(CurrentUnitData, Size, Size,
704 II.DataFlowTraceForFocusFunction);
706 NewSize = MD.Mutate(CurrentUnitData, Size, CurrentMaxMutationLen);
707 assert(NewSize > 0 && "Mutator returned empty unit");
708 assert(NewSize <= CurrentMaxMutationLen && "Mutator return oversized unit");
710 II.NumExecutedMutations++;
712 bool FoundUniqFeatures = false;
713 bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II,
715 TryDetectingAMemoryLeak(CurrentUnitData, Size,
716 /*DuringInitialCorpusExecution*/ false);
718 ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
719 break; // We will mutate this input more in the next rounds.
721 if (Options.ReduceDepth && !FoundUniqFeatures)
726 void Fuzzer::PurgeAllocator() {
727 if (Options.PurgeAllocatorIntervalSec < 0 || !EF->__sanitizer_purge_allocator)
729 if (duration_cast<seconds>(system_clock::now() -
730 LastAllocatorPurgeAttemptTime)
731 .count() < Options.PurgeAllocatorIntervalSec)
734 if (Options.RssLimitMb <= 0 ||
735 GetPeakRSSMb() > static_cast<size_t>(Options.RssLimitMb) / 2)
736 EF->__sanitizer_purge_allocator();
738 LastAllocatorPurgeAttemptTime = system_clock::now();
741 void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
742 const size_t kMaxSaneLen = 1 << 20;
743 const size_t kMinDefaultLen = 4096;
744 Vector<SizedFile> SizedFiles;
747 size_t TotalSize = 0;
748 size_t LastNumFiles = 0;
749 for (auto &Dir : CorpusDirs) {
750 GetSizedFilesFromDir(Dir, &SizedFiles);
751 Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
753 LastNumFiles = SizedFiles.size();
755 for (auto &File : SizedFiles) {
756 MaxSize = Max(File.Size, MaxSize);
757 MinSize = Min(File.Size, MinSize);
758 TotalSize += File.Size;
760 if (Options.MaxLen == 0)
761 SetMaxInputLen(std::min(std::max(kMinDefaultLen, MaxSize), kMaxSaneLen));
762 assert(MaxInputLen > 0);
764 // Test the callback with empty input and never try it again.
766 ExecuteCallback(&dummy, 0);
768 if (SizedFiles.empty()) {
769 Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
770 Unit U({'\n'}); // Valid ASCII input.
771 RunOne(U.data(), U.size());
773 Printf("INFO: seed corpus: files: %zd min: %zdb max: %zdb total: %zdb"
775 SizedFiles.size(), MinSize, MaxSize, TotalSize, GetPeakRSSMb());
776 if (Options.ShuffleAtStartUp)
777 std::shuffle(SizedFiles.begin(), SizedFiles.end(), MD.GetRand());
779 if (Options.PreferSmall) {
780 std::stable_sort(SizedFiles.begin(), SizedFiles.end());
781 assert(SizedFiles.front().Size <= SizedFiles.back().Size);
784 // Load and execute inputs one by one.
785 for (auto &SF : SizedFiles) {
786 auto U = FileToVector(SF.File, MaxInputLen, /*ExitOnError=*/false);
787 assert(U.size() <= MaxInputLen);
788 RunOne(U.data(), U.size());
789 CheckExitOnSrcPosOrItem();
790 TryDetectingAMemoryLeak(U.data(), U.size(),
791 /*DuringInitialCorpusExecution*/ true);
795 PrintStats("INITED");
796 if (!Options.FocusFunction.empty())
797 Printf("INFO: %zd/%zd inputs touch the focus function\n",
798 Corpus.NumInputsThatTouchFocusFunction(), Corpus.size());
799 if (!Options.DataFlowTrace.empty())
800 Printf("INFO: %zd/%zd inputs have the Data Flow Trace\n",
801 Corpus.NumInputsWithDataFlowTrace(), Corpus.size());
803 if (Corpus.empty() && Options.MaxNumberOfRuns) {
804 Printf("ERROR: no interesting inputs were found. "
805 "Is the code instrumented for coverage? Exiting.\n");
810 void Fuzzer::Loop(const Vector<std::string> &CorpusDirs) {
811 ReadAndExecuteSeedCorpora(CorpusDirs);
812 DFT.Clear(); // No need for DFT any more.
813 TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
814 TPC.SetPrintNewFuncs(Options.PrintNewCovFuncs);
815 system_clock::time_point LastCorpusReload = system_clock::now();
816 if (Options.DoCrossOver)
817 MD.SetCorpus(&Corpus);
819 auto Now = system_clock::now();
820 if (duration_cast<seconds>(Now - LastCorpusReload).count() >=
821 Options.ReloadIntervalSec) {
822 RereadOutputCorpus(MaxInputLen);
823 LastCorpusReload = system_clock::now();
825 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
830 // Update TmpMaxMutationLen
831 if (Options.LenControl) {
832 if (TmpMaxMutationLen < MaxMutationLen &&
833 TotalNumberOfRuns - LastCorpusUpdateRun >
834 Options.LenControl * Log(TmpMaxMutationLen)) {
836 Min(MaxMutationLen, TmpMaxMutationLen + Log(TmpMaxMutationLen));
837 LastCorpusUpdateRun = TotalNumberOfRuns;
840 TmpMaxMutationLen = MaxMutationLen;
843 // Perform several mutations and runs.
849 PrintStats("DONE ", "\n");
850 MD.PrintRecommendedDictionary();
853 void Fuzzer::MinimizeCrashLoop(const Unit &U) {
856 while (!TimedOut() && TotalNumberOfRuns < Options.MaxNumberOfRuns) {
857 MD.StartMutationSequence();
858 memcpy(CurrentUnitData, U.data(), U.size());
859 for (int i = 0; i < Options.MutateDepth; i++) {
860 size_t NewSize = MD.Mutate(CurrentUnitData, U.size(), MaxMutationLen);
861 assert(NewSize > 0 && NewSize <= MaxMutationLen);
862 ExecuteCallback(CurrentUnitData, NewSize);
863 PrintPulseAndReportSlowInput(CurrentUnitData, NewSize);
864 TryDetectingAMemoryLeak(CurrentUnitData, NewSize,
865 /*DuringInitialCorpusExecution*/ false);
870 void Fuzzer::AnnounceOutput(const uint8_t *Data, size_t Size) {
871 if (SMR.IsServer()) {
872 SMR.WriteByteArray(Data, Size);
873 } else if (SMR.IsClient()) {
876 size_t OtherSize = SMR.ReadByteArraySize();
877 uint8_t *OtherData = SMR.GetByteArray();
878 if (Size != OtherSize || memcmp(Data, OtherData, Size) != 0) {
880 for (i = 0; i < Min(Size, OtherSize); i++)
881 if (Data[i] != OtherData[i])
883 Printf("==%lu== ERROR: libFuzzer: equivalence-mismatch. Sizes: %zd %zd; "
885 GetPid(), Size, OtherSize, i);
886 DumpCurrentUnit("mismatch-");
887 Printf("SUMMARY: libFuzzer: equivalence-mismatch\n");
889 _Exit(Options.ErrorExitCode);
894 } // namespace fuzzer
898 __attribute__((visibility("default"))) size_t
899 LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
901 return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
905 __attribute__((visibility("default"))) void
906 LLVMFuzzerAnnounceOutput(const uint8_t *Data, size_t Size) {
908 fuzzer::F->AnnounceOutput(Data, Size);