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 // NetBSD's current behavior needs this change too.
279 #if !LIBFUZZER_WINDOWS && !LIBFUZZER_NETBSD
280 if (!InFuzzingThread())
283 if (!RunningUserCallback)
284 return; // We have not started running units yet.
286 duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
289 if (Options.Verbosity >= 2)
290 Printf("AlarmCallback %zd\n", Seconds);
291 if (Seconds >= (size_t)Options.UnitTimeoutSec) {
292 if (EF->__sanitizer_acquire_crash_state &&
293 !EF->__sanitizer_acquire_crash_state())
295 Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
296 Printf(" and the timeout value is %d (use -timeout=N to change)\n",
297 Options.UnitTimeoutSec);
298 DumpCurrentUnit("timeout-");
299 Printf("==%lu== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
302 Printf("SUMMARY: libFuzzer: timeout\n");
304 _Exit(Options.TimeoutExitCode); // Stop right now.
308 void Fuzzer::RssLimitCallback() {
309 if (EF->__sanitizer_acquire_crash_state &&
310 !EF->__sanitizer_acquire_crash_state())
313 "==%lu== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
314 GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
315 Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
316 PrintMemoryProfile();
317 DumpCurrentUnit("oom-");
318 Printf("SUMMARY: libFuzzer: out-of-memory\n");
320 _Exit(Options.ErrorExitCode); // Stop right now.
323 void Fuzzer::PrintStats(const char *Where, const char *End, size_t Units) {
324 size_t ExecPerSec = execPerSec();
325 if (!Options.Verbosity)
327 Printf("#%zd\t%s", TotalNumberOfRuns, Where);
328 if (size_t N = TPC.GetTotalPCCoverage())
329 Printf(" cov: %zd", N);
330 if (size_t N = Corpus.NumFeatures())
331 Printf(" ft: %zd", N);
332 if (!Corpus.empty()) {
333 Printf(" corp: %zd", Corpus.NumActiveUnits());
334 if (size_t N = Corpus.SizeInBytes()) {
337 else if (N < (1 << 24))
338 Printf("/%zdKb", N >> 10);
340 Printf("/%zdMb", N >> 20);
342 if (size_t FF = Corpus.NumInputsThatTouchFocusFunction())
343 Printf(" focus: %zd", FF);
345 if (TmpMaxMutationLen)
346 Printf(" lim: %zd", TmpMaxMutationLen);
348 Printf(" units: %zd", Units);
350 Printf(" exec/s: %zd", ExecPerSec);
351 Printf(" rss: %zdMb", GetPeakRSSMb());
355 void Fuzzer::PrintFinalStats() {
356 if (Options.PrintCoverage)
358 if (Options.DumpCoverage)
360 if (Options.PrintCorpusStats)
362 if (!Options.PrintFinalStats)
364 size_t ExecPerSec = execPerSec();
365 Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
366 Printf("stat::average_exec_per_sec: %zd\n", ExecPerSec);
367 Printf("stat::new_units_added: %zd\n", NumberOfNewUnitsAdded);
368 Printf("stat::slowest_unit_time_sec: %zd\n", TimeOfLongestUnitInSeconds);
369 Printf("stat::peak_rss_mb: %zd\n", GetPeakRSSMb());
372 void Fuzzer::SetMaxInputLen(size_t MaxInputLen) {
373 assert(this->MaxInputLen == 0); // Can only reset MaxInputLen from 0 to non-0.
375 this->MaxInputLen = MaxInputLen;
376 this->MaxMutationLen = MaxInputLen;
377 AllocateCurrentUnitData();
378 Printf("INFO: -max_len is not provided; "
379 "libFuzzer will not generate inputs larger than %zd bytes\n",
383 void Fuzzer::SetMaxMutationLen(size_t MaxMutationLen) {
384 assert(MaxMutationLen && MaxMutationLen <= MaxInputLen);
385 this->MaxMutationLen = MaxMutationLen;
388 void Fuzzer::CheckExitOnSrcPosOrItem() {
389 if (!Options.ExitOnSrcPos.empty()) {
390 static auto *PCsSet = new Set<uintptr_t>;
391 auto HandlePC = [&](uintptr_t PC) {
392 if (!PCsSet->insert(PC).second)
394 std::string Descr = DescribePC("%F %L", PC + 1);
395 if (Descr.find(Options.ExitOnSrcPos) != std::string::npos) {
396 Printf("INFO: found line matching '%s', exiting.\n",
397 Options.ExitOnSrcPos.c_str());
401 TPC.ForEachObservedPC(HandlePC);
403 if (!Options.ExitOnItem.empty()) {
404 if (Corpus.HasUnit(Options.ExitOnItem)) {
405 Printf("INFO: found item with checksum '%s', exiting.\n",
406 Options.ExitOnItem.c_str());
412 void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
413 if (Options.OutputCorpus.empty() || !Options.ReloadIntervalSec)
415 Vector<Unit> AdditionalCorpus;
416 ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
417 &EpochOfLastReadOfOutputCorpus, MaxSize,
418 /*ExitOnError*/ false);
419 if (Options.Verbosity >= 2)
420 Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
421 bool Reloaded = false;
422 for (auto &U : AdditionalCorpus) {
423 if (U.size() > MaxSize)
425 if (!Corpus.HasUnit(U)) {
426 if (RunOne(U.data(), U.size())) {
427 CheckExitOnSrcPosOrItem();
433 PrintStats("RELOAD");
436 void Fuzzer::PrintPulseAndReportSlowInput(const uint8_t *Data, size_t Size) {
438 duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
439 if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
440 secondsSinceProcessStartUp() >= 2)
441 PrintStats("pulse ");
442 if (TimeOfUnit > TimeOfLongestUnitInSeconds * 1.1 &&
443 TimeOfUnit >= Options.ReportSlowUnits) {
444 TimeOfLongestUnitInSeconds = TimeOfUnit;
445 Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
446 WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
450 bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
451 InputInfo *II, bool *FoundUniqFeatures) {
455 ExecuteCallback(Data, Size);
457 UniqFeatureSetTmp.clear();
458 size_t FoundUniqFeaturesOfII = 0;
459 size_t NumUpdatesBefore = Corpus.NumFeatureUpdates();
460 TPC.CollectFeatures([&](size_t Feature) {
461 if (Corpus.AddFeature(Feature, Size, Options.Shrink))
462 UniqFeatureSetTmp.push_back(Feature);
463 if (Options.ReduceInputs && II)
464 if (std::binary_search(II->UniqFeatureSet.begin(),
465 II->UniqFeatureSet.end(), Feature))
466 FoundUniqFeaturesOfII++;
468 if (FoundUniqFeatures)
469 *FoundUniqFeatures = FoundUniqFeaturesOfII;
470 PrintPulseAndReportSlowInput(Data, Size);
471 size_t NumNewFeatures = Corpus.NumFeatureUpdates() - NumUpdatesBefore;
472 if (NumNewFeatures) {
473 TPC.UpdateObservedPCs();
474 Corpus.AddToCorpus({Data, Data + Size}, NumNewFeatures, MayDeleteFile,
475 TPC.ObservedFocusFunction(), UniqFeatureSetTmp, DFT, II);
478 if (II && FoundUniqFeaturesOfII &&
479 II->DataFlowTraceForFocusFunction.empty() &&
480 FoundUniqFeaturesOfII == II->UniqFeatureSet.size() &&
481 II->U.size() > Size) {
482 Corpus.Replace(II, {Data, Data + Size});
488 size_t Fuzzer::GetCurrentUnitInFuzzingThead(const uint8_t **Data) const {
489 assert(InFuzzingThread());
490 *Data = CurrentUnitData;
491 return CurrentUnitSize;
494 void Fuzzer::CrashOnOverwrittenData() {
495 Printf("==%d== ERROR: libFuzzer: fuzz target overwrites it's const input\n",
497 DumpCurrentUnit("crash-");
498 Printf("SUMMARY: libFuzzer: out-of-memory\n");
499 _Exit(Options.ErrorExitCode); // Stop right now.
502 // Compare two arrays, but not all bytes if the arrays are large.
503 static bool LooseMemeq(const uint8_t *A, const uint8_t *B, size_t Size) {
504 const size_t Limit = 64;
506 return !memcmp(A, B, Size);
507 // Compare first and last Limit/2 bytes.
508 return !memcmp(A, B, Limit / 2) &&
509 !memcmp(A + Size - Limit / 2, B + Size - Limit / 2, Limit / 2);
512 void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
513 TPC.RecordInitialStack();
515 assert(InFuzzingThread());
517 SMR.WriteByteArray(Data, Size);
518 // We copy the contents of Unit into a separate heap buffer
519 // so that we reliably find buffer overflows in it.
520 uint8_t *DataCopy = new uint8_t[Size];
521 memcpy(DataCopy, Data, Size);
522 if (EF->__msan_unpoison)
523 EF->__msan_unpoison(DataCopy, Size);
524 if (CurrentUnitData && CurrentUnitData != Data)
525 memcpy(CurrentUnitData, Data, Size);
526 CurrentUnitSize = Size;
528 ScopedEnableMsanInterceptorChecks S;
529 AllocTracer.Start(Options.TraceMalloc);
530 UnitStartTime = system_clock::now();
532 RunningUserCallback = true;
533 int Res = CB(DataCopy, Size);
534 RunningUserCallback = false;
535 UnitStopTime = system_clock::now();
538 HasMoreMallocsThanFrees = AllocTracer.Stop();
540 if (!LooseMemeq(DataCopy, Data, Size))
541 CrashOnOverwrittenData();
546 void Fuzzer::WriteToOutputCorpus(const Unit &U) {
547 if (Options.OnlyASCII)
549 if (Options.OutputCorpus.empty())
551 std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
552 WriteToFile(U, Path);
553 if (Options.Verbosity >= 2)
554 Printf("Written %zd bytes to %s\n", U.size(), Path.c_str());
557 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
558 if (!Options.SaveArtifacts)
560 std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
561 if (!Options.ExactArtifactPath.empty())
562 Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
563 WriteToFile(U, Path);
564 Printf("artifact_prefix='%s'; Test unit written to %s\n",
565 Options.ArtifactPrefix.c_str(), Path.c_str());
566 if (U.size() <= kMaxUnitSizeToPrint)
567 Printf("Base64: %s\n", Base64(U).c_str());
570 void Fuzzer::PrintStatusForNewUnit(const Unit &U, const char *Text) {
571 if (!Options.PrintNEW)
573 PrintStats(Text, "");
574 if (Options.Verbosity) {
575 Printf(" L: %zd/%zd ", U.size(), Corpus.MaxInputSize());
576 MD.PrintMutationSequence();
581 void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
582 II->NumSuccessfullMutations++;
583 MD.RecordSuccessfulMutationSequence();
584 PrintStatusForNewUnit(U, II->Reduced ? "REDUCE" : "NEW ");
585 WriteToOutputCorpus(U);
586 NumberOfNewUnitsAdded++;
587 CheckExitOnSrcPosOrItem(); // Check only after the unit is saved to corpus.
588 LastCorpusUpdateRun = TotalNumberOfRuns;
591 // Tries detecting a memory leak on the particular input that we have just
592 // executed before calling this function.
593 void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
594 bool DuringInitialCorpusExecution) {
595 if (!HasMoreMallocsThanFrees)
596 return; // mallocs==frees, a leak is unlikely.
597 if (!Options.DetectLeaks)
599 if (!DuringInitialCorpusExecution &&
600 TotalNumberOfRuns >= Options.MaxNumberOfRuns)
602 if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
603 !(EF->__lsan_do_recoverable_leak_check))
605 // Run the target once again, but with lsan disabled so that if there is
606 // a real leak we do not report it twice.
607 EF->__lsan_disable();
608 ExecuteCallback(Data, Size);
610 if (!HasMoreMallocsThanFrees)
611 return; // a leak is unlikely.
612 if (NumberOfLeakDetectionAttempts++ > 1000) {
613 Options.DetectLeaks = false;
614 Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
615 " Most likely the target function accumulates allocated\n"
616 " memory in a global state w/o actually leaking it.\n"
617 " You may try running this binary with -trace_malloc=[12]"
618 " to get a trace of mallocs and frees.\n"
619 " If LeakSanitizer is enabled in this process it will still\n"
620 " run on the process shutdown.\n");
623 // Now perform the actual lsan pass. This is expensive and we must ensure
624 // we don't call it too often.
625 if (EF->__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
626 if (DuringInitialCorpusExecution)
627 Printf("\nINFO: a leak has been found in the initial corpus.\n\n");
628 Printf("INFO: to ignore leaks on libFuzzer side use -detect_leaks=0.\n\n");
629 CurrentUnitSize = Size;
630 DumpCurrentUnit("leak-");
632 _Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
636 void Fuzzer::MutateAndTestOne() {
637 MD.StartMutationSequence();
639 auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
640 const auto &U = II.U;
641 memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
642 assert(CurrentUnitData);
643 size_t Size = U.size();
644 assert(Size <= MaxInputLen && "Oversized Unit");
645 memcpy(CurrentUnitData, U.data(), Size);
647 assert(MaxMutationLen > 0);
649 size_t CurrentMaxMutationLen =
650 Min(MaxMutationLen, Max(U.size(), TmpMaxMutationLen));
651 assert(CurrentMaxMutationLen > 0);
653 for (int i = 0; i < Options.MutateDepth; i++) {
654 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
656 MaybeExitGracefully();
658 if (II.HasFocusFunction && !II.DataFlowTraceForFocusFunction.empty() &&
659 Size <= CurrentMaxMutationLen)
660 NewSize = MD.MutateWithMask(CurrentUnitData, Size, Size,
661 II.DataFlowTraceForFocusFunction);
663 NewSize = MD.Mutate(CurrentUnitData, Size, CurrentMaxMutationLen);
664 assert(NewSize > 0 && "Mutator returned empty unit");
665 assert(NewSize <= CurrentMaxMutationLen && "Mutator return oversized unit");
667 II.NumExecutedMutations++;
669 bool FoundUniqFeatures = false;
670 bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II,
672 TryDetectingAMemoryLeak(CurrentUnitData, Size,
673 /*DuringInitialCorpusExecution*/ false);
675 ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
676 break; // We will mutate this input more in the next rounds.
678 if (Options.ReduceDepth && !FoundUniqFeatures)
683 void Fuzzer::PurgeAllocator() {
684 if (Options.PurgeAllocatorIntervalSec < 0 || !EF->__sanitizer_purge_allocator)
686 if (duration_cast<seconds>(system_clock::now() -
687 LastAllocatorPurgeAttemptTime)
688 .count() < Options.PurgeAllocatorIntervalSec)
691 if (Options.RssLimitMb <= 0 ||
692 GetPeakRSSMb() > static_cast<size_t>(Options.RssLimitMb) / 2)
693 EF->__sanitizer_purge_allocator();
695 LastAllocatorPurgeAttemptTime = system_clock::now();
698 void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
699 const size_t kMaxSaneLen = 1 << 20;
700 const size_t kMinDefaultLen = 4096;
701 Vector<SizedFile> SizedFiles;
704 size_t TotalSize = 0;
705 size_t LastNumFiles = 0;
706 for (auto &Dir : CorpusDirs) {
707 GetSizedFilesFromDir(Dir, &SizedFiles);
708 Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
710 LastNumFiles = SizedFiles.size();
712 for (auto &File : SizedFiles) {
713 MaxSize = Max(File.Size, MaxSize);
714 MinSize = Min(File.Size, MinSize);
715 TotalSize += File.Size;
717 if (Options.MaxLen == 0)
718 SetMaxInputLen(std::min(std::max(kMinDefaultLen, MaxSize), kMaxSaneLen));
719 assert(MaxInputLen > 0);
721 // Test the callback with empty input and never try it again.
723 ExecuteCallback(&dummy, 0);
725 if (SizedFiles.empty()) {
726 Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
727 Unit U({'\n'}); // Valid ASCII input.
728 RunOne(U.data(), U.size());
730 Printf("INFO: seed corpus: files: %zd min: %zdb max: %zdb total: %zdb"
732 SizedFiles.size(), MinSize, MaxSize, TotalSize, GetPeakRSSMb());
733 if (Options.ShuffleAtStartUp)
734 std::shuffle(SizedFiles.begin(), SizedFiles.end(), MD.GetRand());
736 if (Options.PreferSmall) {
737 std::stable_sort(SizedFiles.begin(), SizedFiles.end());
738 assert(SizedFiles.front().Size <= SizedFiles.back().Size);
741 // Load and execute inputs one by one.
742 for (auto &SF : SizedFiles) {
743 auto U = FileToVector(SF.File, MaxInputLen, /*ExitOnError=*/false);
744 assert(U.size() <= MaxInputLen);
745 RunOne(U.data(), U.size());
746 CheckExitOnSrcPosOrItem();
747 TryDetectingAMemoryLeak(U.data(), U.size(),
748 /*DuringInitialCorpusExecution*/ true);
752 PrintStats("INITED");
753 if (!Options.FocusFunction.empty())
754 Printf("INFO: %zd/%zd inputs touch the focus function\n",
755 Corpus.NumInputsThatTouchFocusFunction(), Corpus.size());
756 if (!Options.DataFlowTrace.empty())
757 Printf("INFO: %zd/%zd inputs have the Data Flow Trace\n",
758 Corpus.NumInputsWithDataFlowTrace(), Corpus.size());
760 if (Corpus.empty() && Options.MaxNumberOfRuns) {
761 Printf("ERROR: no interesting inputs were found. "
762 "Is the code instrumented for coverage? Exiting.\n");
767 void Fuzzer::Loop(const Vector<std::string> &CorpusDirs) {
768 ReadAndExecuteSeedCorpora(CorpusDirs);
769 DFT.Clear(); // No need for DFT any more.
770 TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
771 TPC.SetPrintNewFuncs(Options.PrintNewCovFuncs);
772 system_clock::time_point LastCorpusReload = system_clock::now();
773 if (Options.DoCrossOver)
774 MD.SetCorpus(&Corpus);
776 auto Now = system_clock::now();
777 if (duration_cast<seconds>(Now - LastCorpusReload).count() >=
778 Options.ReloadIntervalSec) {
779 RereadOutputCorpus(MaxInputLen);
780 LastCorpusReload = system_clock::now();
782 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
787 // Update TmpMaxMutationLen
788 if (Options.LenControl) {
789 if (TmpMaxMutationLen < MaxMutationLen &&
790 TotalNumberOfRuns - LastCorpusUpdateRun >
791 Options.LenControl * Log(TmpMaxMutationLen)) {
793 Min(MaxMutationLen, TmpMaxMutationLen + Log(TmpMaxMutationLen));
794 LastCorpusUpdateRun = TotalNumberOfRuns;
797 TmpMaxMutationLen = MaxMutationLen;
800 // Perform several mutations and runs.
806 PrintStats("DONE ", "\n");
807 MD.PrintRecommendedDictionary();
810 void Fuzzer::MinimizeCrashLoop(const Unit &U) {
813 while (!TimedOut() && TotalNumberOfRuns < Options.MaxNumberOfRuns) {
814 MD.StartMutationSequence();
815 memcpy(CurrentUnitData, U.data(), U.size());
816 for (int i = 0; i < Options.MutateDepth; i++) {
817 size_t NewSize = MD.Mutate(CurrentUnitData, U.size(), MaxMutationLen);
818 assert(NewSize > 0 && NewSize <= MaxMutationLen);
819 ExecuteCallback(CurrentUnitData, NewSize);
820 PrintPulseAndReportSlowInput(CurrentUnitData, NewSize);
821 TryDetectingAMemoryLeak(CurrentUnitData, NewSize,
822 /*DuringInitialCorpusExecution*/ false);
827 void Fuzzer::AnnounceOutput(const uint8_t *Data, size_t Size) {
828 if (SMR.IsServer()) {
829 SMR.WriteByteArray(Data, Size);
830 } else if (SMR.IsClient()) {
833 size_t OtherSize = SMR.ReadByteArraySize();
834 uint8_t *OtherData = SMR.GetByteArray();
835 if (Size != OtherSize || memcmp(Data, OtherData, Size) != 0) {
837 for (i = 0; i < Min(Size, OtherSize); i++)
838 if (Data[i] != OtherData[i])
840 Printf("==%lu== ERROR: libFuzzer: equivalence-mismatch. Sizes: %zd %zd; "
842 GetPid(), Size, OtherSize, i);
843 DumpCurrentUnit("mismatch-");
844 Printf("SUMMARY: libFuzzer: equivalence-mismatch\n");
846 _Exit(Options.ErrorExitCode);
851 } // namespace fuzzer
855 __attribute__((visibility("default"))) size_t
856 LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
858 return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
862 __attribute__((visibility("default"))) void
863 LLVMFuzzerAnnounceOutput(const uint8_t *Data, size_t Size) {
865 fuzzer::F->AnnounceOutput(Data, Size);