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 // Only one Fuzzer per process.
49 // Leak detection is expensive, so we first check if there were more mallocs
50 // than frees (using the sanitizer malloc hooks) and only then try to call lsan.
51 struct MallocFreeTracer {
52 void Start(int TraceLevel) {
53 this->TraceLevel = TraceLevel;
55 Printf("MallocFreeTracer: START\n");
59 // Returns true if there were more mallocs than frees.
62 Printf("MallocFreeTracer: STOP %zd %zd (%s)\n", Mallocs.load(),
63 Frees.load(), Mallocs == Frees ? "same" : "DIFFERENT");
64 bool Result = Mallocs > Frees;
70 std::atomic<size_t> Mallocs;
71 std::atomic<size_t> Frees;
74 std::recursive_mutex TraceMutex;
75 bool TraceDisabled = false;
78 static MallocFreeTracer AllocTracer;
80 // Locks printing and avoids nested hooks triggered from mallocs/frees in
84 TraceLock() : Lock(AllocTracer.TraceMutex) {
85 AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled;
87 ~TraceLock() { AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled; }
89 bool IsDisabled() const {
90 // This is already inverted value.
91 return !AllocTracer.TraceDisabled;
95 std::lock_guard<std::recursive_mutex> Lock;
98 ATTRIBUTE_NO_SANITIZE_MEMORY
99 void MallocHook(const volatile void *ptr, size_t size) {
100 size_t N = AllocTracer.Mallocs++;
101 F->HandleMalloc(size);
102 if (int TraceLevel = AllocTracer.TraceLevel) {
104 if (Lock.IsDisabled())
106 Printf("MALLOC[%zd] %p %zd\n", N, ptr, size);
107 if (TraceLevel >= 2 && EF)
108 EF->__sanitizer_print_stack_trace();
112 ATTRIBUTE_NO_SANITIZE_MEMORY
113 void FreeHook(const volatile void *ptr) {
114 size_t N = AllocTracer.Frees++;
115 if (int TraceLevel = AllocTracer.TraceLevel) {
117 if (Lock.IsDisabled())
119 Printf("FREE[%zd] %p\n", N, ptr);
120 if (TraceLevel >= 2 && EF)
121 EF->__sanitizer_print_stack_trace();
125 // Crash on a single malloc that exceeds the rss limit.
126 void Fuzzer::HandleMalloc(size_t Size) {
127 if (!Options.MallocLimitMb || (Size >> 20) < (size_t)Options.MallocLimitMb)
129 Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n", GetPid(),
131 Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
132 if (EF->__sanitizer_print_stack_trace)
133 EF->__sanitizer_print_stack_trace();
134 DumpCurrentUnit("oom-");
135 Printf("SUMMARY: libFuzzer: out-of-memory\n");
137 _Exit(Options.ErrorExitCode); // Stop right now.
140 Fuzzer::Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
141 FuzzingOptions Options)
142 : CB(CB), Corpus(Corpus), MD(MD), Options(Options) {
143 if (EF->__sanitizer_set_death_callback)
144 EF->__sanitizer_set_death_callback(StaticDeathCallback);
149 if (Options.DetectLeaks && EF->__sanitizer_install_malloc_and_free_hooks)
150 EF->__sanitizer_install_malloc_and_free_hooks(MallocHook, FreeHook);
151 TPC.SetUseCounters(Options.UseCounters);
152 TPC.SetUseValueProfile(Options.UseValueProfile);
153 TPC.SetUseClangCoverage(Options.UseClangCoverage);
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));
168 void Fuzzer::AllocateCurrentUnitData() {
169 if (CurrentUnitData || MaxInputLen == 0)
171 CurrentUnitData = new uint8_t[MaxInputLen];
174 void Fuzzer::StaticDeathCallback() {
179 void Fuzzer::DumpCurrentUnit(const char *Prefix) {
180 if (!CurrentUnitData)
181 return; // Happens when running individual inputs.
182 MD.PrintMutationSequence();
183 Printf("; base unit: %s\n", Sha1ToString(BaseSha1).c_str());
184 size_t UnitSize = CurrentUnitSize;
185 if (UnitSize <= kMaxUnitSizeToPrint) {
186 PrintHexArray(CurrentUnitData, UnitSize, "\n");
187 PrintASCII(CurrentUnitData, UnitSize, "\n");
189 WriteUnitToFileWithPrefix({CurrentUnitData, CurrentUnitData + UnitSize},
194 void Fuzzer::DeathCallback() {
195 DumpCurrentUnit("crash-");
199 void Fuzzer::StaticAlarmCallback() {
204 void Fuzzer::StaticCrashSignalCallback() {
209 void Fuzzer::StaticExitCallback() {
214 void Fuzzer::StaticInterruptCallback() {
216 F->InterruptCallback();
219 void Fuzzer::StaticGracefulExitCallback() {
221 F->GracefulExitRequested = true;
222 Printf("INFO: signal received, trying to exit gracefully\n");
225 void Fuzzer::StaticFileSizeExceedCallback() {
226 Printf("==%lu== ERROR: libFuzzer: file size exceeded\n", GetPid());
230 void Fuzzer::CrashCallback() {
231 Printf("==%lu== ERROR: libFuzzer: deadly signal\n", GetPid());
232 if (EF->__sanitizer_print_stack_trace)
233 EF->__sanitizer_print_stack_trace();
234 Printf("NOTE: libFuzzer has rudimentary signal handlers.\n"
235 " Combine libFuzzer with AddressSanitizer or similar for better "
237 Printf("SUMMARY: libFuzzer: deadly signal\n");
238 DumpCurrentUnit("crash-");
240 _Exit(Options.ErrorExitCode); // Stop right now.
243 void Fuzzer::ExitCallback() {
245 return; // This exit did not come from the user callback
246 Printf("==%lu== ERROR: libFuzzer: fuzz target exited\n", GetPid());
247 if (EF->__sanitizer_print_stack_trace)
248 EF->__sanitizer_print_stack_trace();
249 Printf("SUMMARY: libFuzzer: fuzz target exited\n");
250 DumpCurrentUnit("crash-");
252 _Exit(Options.ErrorExitCode);
255 void Fuzzer::MaybeExitGracefully() {
256 if (!GracefulExitRequested) return;
257 Printf("==%lu== INFO: libFuzzer: exiting as requested\n", GetPid());
262 void Fuzzer::InterruptCallback() {
263 Printf("==%lu== libFuzzer: run interrupted; exiting\n", GetPid());
265 _Exit(0); // Stop right now, don't perform any at-exit actions.
269 void Fuzzer::AlarmCallback() {
270 assert(Options.UnitTimeoutSec > 0);
271 // In Windows Alarm callback is executed by a different thread.
272 #if !LIBFUZZER_WINDOWS
273 if (!InFuzzingThread())
277 return; // We have not started running units yet.
279 duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
282 if (Options.Verbosity >= 2)
283 Printf("AlarmCallback %zd\n", Seconds);
284 if (Seconds >= (size_t)Options.UnitTimeoutSec) {
285 Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
286 Printf(" and the timeout value is %d (use -timeout=N to change)\n",
287 Options.UnitTimeoutSec);
288 DumpCurrentUnit("timeout-");
289 Printf("==%lu== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
291 if (EF->__sanitizer_print_stack_trace)
292 EF->__sanitizer_print_stack_trace();
293 Printf("SUMMARY: libFuzzer: timeout\n");
295 _Exit(Options.TimeoutExitCode); // Stop right now.
299 void Fuzzer::RssLimitCallback() {
301 "==%lu== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
302 GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
303 Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
304 if (EF->__sanitizer_print_memory_profile)
305 EF->__sanitizer_print_memory_profile(95, 8);
306 DumpCurrentUnit("oom-");
307 Printf("SUMMARY: libFuzzer: out-of-memory\n");
309 _Exit(Options.ErrorExitCode); // Stop right now.
312 void Fuzzer::PrintStats(const char *Where, const char *End, size_t Units) {
313 size_t ExecPerSec = execPerSec();
314 if (!Options.Verbosity)
316 Printf("#%zd\t%s", TotalNumberOfRuns, Where);
317 if (size_t N = TPC.GetTotalPCCoverage())
318 Printf(" cov: %zd", N);
319 if (size_t N = Corpus.NumFeatures())
320 Printf(" ft: %zd", N);
321 if (!Corpus.empty()) {
322 Printf(" corp: %zd", Corpus.NumActiveUnits());
323 if (size_t N = Corpus.SizeInBytes()) {
326 else if (N < (1 << 24))
327 Printf("/%zdKb", N >> 10);
329 Printf("/%zdMb", N >> 20);
333 Printf(" units: %zd", Units);
335 Printf(" exec/s: %zd", ExecPerSec);
336 Printf(" rss: %zdMb", GetPeakRSSMb());
340 void Fuzzer::PrintFinalStats() {
341 if (Options.PrintCoverage)
343 if (Options.DumpCoverage)
345 if (Options.PrintCorpusStats)
347 if (!Options.PrintFinalStats)
349 size_t ExecPerSec = execPerSec();
350 Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
351 Printf("stat::average_exec_per_sec: %zd\n", ExecPerSec);
352 Printf("stat::new_units_added: %zd\n", NumberOfNewUnitsAdded);
353 Printf("stat::slowest_unit_time_sec: %zd\n", TimeOfLongestUnitInSeconds);
354 Printf("stat::peak_rss_mb: %zd\n", GetPeakRSSMb());
357 void Fuzzer::SetMaxInputLen(size_t MaxInputLen) {
358 assert(this->MaxInputLen == 0); // Can only reset MaxInputLen from 0 to non-0.
360 this->MaxInputLen = MaxInputLen;
361 this->MaxMutationLen = MaxInputLen;
362 AllocateCurrentUnitData();
363 Printf("INFO: -max_len is not provided; "
364 "libFuzzer will not generate inputs larger than %zd bytes\n",
368 void Fuzzer::SetMaxMutationLen(size_t MaxMutationLen) {
369 assert(MaxMutationLen && MaxMutationLen <= MaxInputLen);
370 this->MaxMutationLen = MaxMutationLen;
373 void Fuzzer::CheckExitOnSrcPosOrItem() {
374 if (!Options.ExitOnSrcPos.empty()) {
375 static auto *PCsSet = new Set<uintptr_t>;
376 auto HandlePC = [&](uintptr_t PC) {
377 if (!PCsSet->insert(PC).second)
379 std::string Descr = DescribePC("%F %L", PC + 1);
380 if (Descr.find(Options.ExitOnSrcPos) != std::string::npos) {
381 Printf("INFO: found line matching '%s', exiting.\n",
382 Options.ExitOnSrcPos.c_str());
386 TPC.ForEachObservedPC(HandlePC);
388 if (!Options.ExitOnItem.empty()) {
389 if (Corpus.HasUnit(Options.ExitOnItem)) {
390 Printf("INFO: found item with checksum '%s', exiting.\n",
391 Options.ExitOnItem.c_str());
397 void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
398 if (Options.OutputCorpus.empty() || !Options.ReloadIntervalSec)
400 Vector<Unit> AdditionalCorpus;
401 ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
402 &EpochOfLastReadOfOutputCorpus, MaxSize,
403 /*ExitOnError*/ false);
404 if (Options.Verbosity >= 2)
405 Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
406 bool Reloaded = false;
407 for (auto &U : AdditionalCorpus) {
408 if (U.size() > MaxSize)
410 if (!Corpus.HasUnit(U)) {
411 if (RunOne(U.data(), U.size())) {
412 CheckExitOnSrcPosOrItem();
418 PrintStats("RELOAD");
421 void Fuzzer::PrintPulseAndReportSlowInput(const uint8_t *Data, size_t Size) {
423 duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
424 if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
425 secondsSinceProcessStartUp() >= 2)
426 PrintStats("pulse ");
427 if (TimeOfUnit > TimeOfLongestUnitInSeconds * 1.1 &&
428 TimeOfUnit >= Options.ReportSlowUnits) {
429 TimeOfLongestUnitInSeconds = TimeOfUnit;
430 Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
431 WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
435 bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
436 InputInfo *II, bool *FoundUniqFeatures) {
440 ExecuteCallback(Data, Size);
442 UniqFeatureSetTmp.clear();
443 size_t FoundUniqFeaturesOfII = 0;
444 size_t NumUpdatesBefore = Corpus.NumFeatureUpdates();
445 TPC.CollectFeatures([&](size_t Feature) {
446 if (Options.UseFeatureFrequency)
447 Corpus.UpdateFeatureFrequency(Feature);
448 if (Corpus.AddFeature(Feature, Size, Options.Shrink))
449 UniqFeatureSetTmp.push_back(Feature);
450 if (Options.ReduceInputs && II)
451 if (std::binary_search(II->UniqFeatureSet.begin(),
452 II->UniqFeatureSet.end(), Feature))
453 FoundUniqFeaturesOfII++;
455 if (FoundUniqFeatures)
456 *FoundUniqFeatures = FoundUniqFeaturesOfII;
457 PrintPulseAndReportSlowInput(Data, Size);
458 size_t NumNewFeatures = Corpus.NumFeatureUpdates() - NumUpdatesBefore;
459 if (NumNewFeatures) {
460 TPC.UpdateObservedPCs();
461 Corpus.AddToCorpus({Data, Data + Size}, NumNewFeatures, MayDeleteFile,
465 if (II && FoundUniqFeaturesOfII &&
466 FoundUniqFeaturesOfII == II->UniqFeatureSet.size() &&
467 II->U.size() > Size) {
468 Corpus.Replace(II, {Data, Data + Size});
474 size_t Fuzzer::GetCurrentUnitInFuzzingThead(const uint8_t **Data) const {
475 assert(InFuzzingThread());
476 *Data = CurrentUnitData;
477 return CurrentUnitSize;
480 void Fuzzer::CrashOnOverwrittenData() {
481 Printf("==%d== ERROR: libFuzzer: fuzz target overwrites it's const input\n",
483 DumpCurrentUnit("crash-");
484 Printf("SUMMARY: libFuzzer: out-of-memory\n");
485 _Exit(Options.ErrorExitCode); // Stop right now.
488 // Compare two arrays, but not all bytes if the arrays are large.
489 static bool LooseMemeq(const uint8_t *A, const uint8_t *B, size_t Size) {
490 const size_t Limit = 64;
492 return !memcmp(A, B, Size);
493 // Compare first and last Limit/2 bytes.
494 return !memcmp(A, B, Limit / 2) &&
495 !memcmp(A + Size - Limit / 2, B + Size - Limit / 2, Limit / 2);
498 void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
499 TPC.RecordInitialStack();
501 assert(InFuzzingThread());
503 SMR.WriteByteArray(Data, Size);
504 // We copy the contents of Unit into a separate heap buffer
505 // so that we reliably find buffer overflows in it.
506 uint8_t *DataCopy = new uint8_t[Size];
507 memcpy(DataCopy, Data, Size);
508 if (CurrentUnitData && CurrentUnitData != Data)
509 memcpy(CurrentUnitData, Data, Size);
510 CurrentUnitSize = Size;
511 AllocTracer.Start(Options.TraceMalloc);
512 UnitStartTime = system_clock::now();
515 int Res = CB(DataCopy, Size);
517 UnitStopTime = system_clock::now();
520 HasMoreMallocsThanFrees = AllocTracer.Stop();
521 if (!LooseMemeq(DataCopy, Data, Size))
522 CrashOnOverwrittenData();
527 void Fuzzer::WriteToOutputCorpus(const Unit &U) {
528 if (Options.OnlyASCII)
530 if (Options.OutputCorpus.empty())
532 std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
533 WriteToFile(U, Path);
534 if (Options.Verbosity >= 2)
535 Printf("Written %zd bytes to %s\n", U.size(), Path.c_str());
538 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
539 if (!Options.SaveArtifacts)
541 std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
542 if (!Options.ExactArtifactPath.empty())
543 Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
544 WriteToFile(U, Path);
545 Printf("artifact_prefix='%s'; Test unit written to %s\n",
546 Options.ArtifactPrefix.c_str(), Path.c_str());
547 if (U.size() <= kMaxUnitSizeToPrint)
548 Printf("Base64: %s\n", Base64(U).c_str());
551 void Fuzzer::PrintStatusForNewUnit(const Unit &U, const char *Text) {
552 if (!Options.PrintNEW)
554 PrintStats(Text, "");
555 if (Options.Verbosity) {
556 Printf(" L: %zd/%zd ", U.size(), Corpus.MaxInputSize());
557 MD.PrintMutationSequence();
562 void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
563 II->NumSuccessfullMutations++;
564 MD.RecordSuccessfulMutationSequence();
565 PrintStatusForNewUnit(U, II->Reduced ? "REDUCE" : "NEW ");
566 WriteToOutputCorpus(U);
567 NumberOfNewUnitsAdded++;
568 CheckExitOnSrcPosOrItem(); // Check only after the unit is saved to corpus.
569 LastCorpusUpdateRun = TotalNumberOfRuns;
572 // Tries detecting a memory leak on the particular input that we have just
573 // executed before calling this function.
574 void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
575 bool DuringInitialCorpusExecution) {
576 if (!HasMoreMallocsThanFrees)
577 return; // mallocs==frees, a leak is unlikely.
578 if (!Options.DetectLeaks)
580 if (!DuringInitialCorpusExecution &&
581 TotalNumberOfRuns >= Options.MaxNumberOfRuns)
583 if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
584 !(EF->__lsan_do_recoverable_leak_check))
586 // Run the target once again, but with lsan disabled so that if there is
587 // a real leak we do not report it twice.
588 EF->__lsan_disable();
589 ExecuteCallback(Data, Size);
591 if (!HasMoreMallocsThanFrees)
592 return; // a leak is unlikely.
593 if (NumberOfLeakDetectionAttempts++ > 1000) {
594 Options.DetectLeaks = false;
595 Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
596 " Most likely the target function accumulates allocated\n"
597 " memory in a global state w/o actually leaking it.\n"
598 " You may try running this binary with -trace_malloc=[12]"
599 " to get a trace of mallocs and frees.\n"
600 " If LeakSanitizer is enabled in this process it will still\n"
601 " run on the process shutdown.\n");
604 // Now perform the actual lsan pass. This is expensive and we must ensure
605 // we don't call it too often.
606 if (EF->__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
607 if (DuringInitialCorpusExecution)
608 Printf("\nINFO: a leak has been found in the initial corpus.\n\n");
609 Printf("INFO: to ignore leaks on libFuzzer side use -detect_leaks=0.\n\n");
610 CurrentUnitSize = Size;
611 DumpCurrentUnit("leak-");
613 _Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
617 void Fuzzer::MutateAndTestOne() {
618 MD.StartMutationSequence();
620 auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
621 if (Options.UseFeatureFrequency)
622 Corpus.UpdateFeatureFrequencyScore(&II);
623 const auto &U = II.U;
624 memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
625 assert(CurrentUnitData);
626 size_t Size = U.size();
627 assert(Size <= MaxInputLen && "Oversized Unit");
628 memcpy(CurrentUnitData, U.data(), Size);
630 assert(MaxMutationLen > 0);
632 size_t CurrentMaxMutationLen =
633 Min(MaxMutationLen, Max(U.size(), TmpMaxMutationLen));
634 assert(CurrentMaxMutationLen > 0);
636 for (int i = 0; i < Options.MutateDepth; i++) {
637 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
639 MaybeExitGracefully();
641 NewSize = MD.Mutate(CurrentUnitData, Size, CurrentMaxMutationLen);
642 assert(NewSize > 0 && "Mutator returned empty unit");
643 assert(NewSize <= CurrentMaxMutationLen && "Mutator return oversized unit");
645 II.NumExecutedMutations++;
647 bool FoundUniqFeatures = false;
648 bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II,
650 TryDetectingAMemoryLeak(CurrentUnitData, Size,
651 /*DuringInitialCorpusExecution*/ false);
653 ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
654 break; // We will mutate this input more in the next rounds.
656 if (Options.ReduceDepth && !FoundUniqFeatures)
661 void Fuzzer::PurgeAllocator() {
662 if (Options.PurgeAllocatorIntervalSec < 0 || !EF->__sanitizer_purge_allocator)
664 if (duration_cast<seconds>(system_clock::now() -
665 LastAllocatorPurgeAttemptTime)
666 .count() < Options.PurgeAllocatorIntervalSec)
669 if (Options.RssLimitMb <= 0 ||
670 GetPeakRSSMb() > static_cast<size_t>(Options.RssLimitMb) / 2)
671 EF->__sanitizer_purge_allocator();
673 LastAllocatorPurgeAttemptTime = system_clock::now();
676 void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
677 const size_t kMaxSaneLen = 1 << 20;
678 const size_t kMinDefaultLen = 4096;
679 Vector<SizedFile> SizedFiles;
682 size_t TotalSize = 0;
683 size_t LastNumFiles = 0;
684 for (auto &Dir : CorpusDirs) {
685 GetSizedFilesFromDir(Dir, &SizedFiles);
686 Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
688 LastNumFiles = SizedFiles.size();
690 for (auto &File : SizedFiles) {
691 MaxSize = Max(File.Size, MaxSize);
692 MinSize = Min(File.Size, MinSize);
693 TotalSize += File.Size;
695 if (Options.MaxLen == 0)
696 SetMaxInputLen(std::min(std::max(kMinDefaultLen, MaxSize), kMaxSaneLen));
697 assert(MaxInputLen > 0);
699 // Test the callback with empty input and never try it again.
701 ExecuteCallback(&dummy, 0);
703 if (SizedFiles.empty()) {
704 Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
705 Unit U({'\n'}); // Valid ASCII input.
706 RunOne(U.data(), U.size());
708 Printf("INFO: seed corpus: files: %zd min: %zdb max: %zdb total: %zdb"
710 SizedFiles.size(), MinSize, MaxSize, TotalSize, GetPeakRSSMb());
711 if (Options.ShuffleAtStartUp)
712 std::shuffle(SizedFiles.begin(), SizedFiles.end(), MD.GetRand());
714 if (Options.PreferSmall) {
715 std::stable_sort(SizedFiles.begin(), SizedFiles.end());
716 assert(SizedFiles.front().Size <= SizedFiles.back().Size);
719 // Load and execute inputs one by one.
720 for (auto &SF : SizedFiles) {
721 auto U = FileToVector(SF.File, MaxInputLen, /*ExitOnError=*/false);
722 assert(U.size() <= MaxInputLen);
723 RunOne(U.data(), U.size());
724 CheckExitOnSrcPosOrItem();
725 TryDetectingAMemoryLeak(U.data(), U.size(),
726 /*DuringInitialCorpusExecution*/ true);
730 PrintStats("INITED");
731 if (Corpus.empty()) {
732 Printf("ERROR: no interesting inputs were found. "
733 "Is the code instrumented for coverage? Exiting.\n");
738 void Fuzzer::Loop(const Vector<std::string> &CorpusDirs) {
739 ReadAndExecuteSeedCorpora(CorpusDirs);
740 TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
741 TPC.SetPrintNewFuncs(Options.PrintNewCovFuncs);
742 system_clock::time_point LastCorpusReload = system_clock::now();
743 if (Options.DoCrossOver)
744 MD.SetCorpus(&Corpus);
746 auto Now = system_clock::now();
747 if (duration_cast<seconds>(Now - LastCorpusReload).count() >=
748 Options.ReloadIntervalSec) {
749 RereadOutputCorpus(MaxInputLen);
750 LastCorpusReload = system_clock::now();
752 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
757 // Update TmpMaxMutationLen
758 if (Options.ExperimentalLenControl) {
759 if (TmpMaxMutationLen < MaxMutationLen &&
760 TotalNumberOfRuns - LastCorpusUpdateRun >
761 Options.ExperimentalLenControl * Log(TmpMaxMutationLen)) {
763 Min(MaxMutationLen, TmpMaxMutationLen + Log(TmpMaxMutationLen));
764 if (TmpMaxMutationLen <= MaxMutationLen)
765 Printf("#%zd\tTEMP_MAX_LEN: %zd (%zd %zd)\n", TotalNumberOfRuns,
766 TmpMaxMutationLen, Options.ExperimentalLenControl,
767 LastCorpusUpdateRun);
768 LastCorpusUpdateRun = TotalNumberOfRuns;
771 TmpMaxMutationLen = MaxMutationLen;
774 // Perform several mutations and runs.
780 PrintStats("DONE ", "\n");
781 MD.PrintRecommendedDictionary();
784 void Fuzzer::MinimizeCrashLoop(const Unit &U) {
787 while (!TimedOut() && TotalNumberOfRuns < Options.MaxNumberOfRuns) {
788 MD.StartMutationSequence();
789 memcpy(CurrentUnitData, U.data(), U.size());
790 for (int i = 0; i < Options.MutateDepth; i++) {
791 size_t NewSize = MD.Mutate(CurrentUnitData, U.size(), MaxMutationLen);
792 assert(NewSize > 0 && NewSize <= MaxMutationLen);
793 ExecuteCallback(CurrentUnitData, NewSize);
794 PrintPulseAndReportSlowInput(CurrentUnitData, NewSize);
795 TryDetectingAMemoryLeak(CurrentUnitData, NewSize,
796 /*DuringInitialCorpusExecution*/ false);
801 void Fuzzer::AnnounceOutput(const uint8_t *Data, size_t Size) {
802 if (SMR.IsServer()) {
803 SMR.WriteByteArray(Data, Size);
804 } else if (SMR.IsClient()) {
807 size_t OtherSize = SMR.ReadByteArraySize();
808 uint8_t *OtherData = SMR.GetByteArray();
809 if (Size != OtherSize || memcmp(Data, OtherData, Size) != 0) {
811 for (i = 0; i < Min(Size, OtherSize); i++)
812 if (Data[i] != OtherData[i])
814 Printf("==%lu== ERROR: libFuzzer: equivalence-mismatch. Sizes: %zd %zd; "
816 GetPid(), Size, OtherSize, i);
817 DumpCurrentUnit("mismatch-");
818 Printf("SUMMARY: libFuzzer: equivalence-mismatch\n");
820 _Exit(Options.ErrorExitCode);
825 } // namespace fuzzer
829 size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
831 return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
835 void LLVMFuzzerAnnounceOutput(const uint8_t *Data, size_t Size) {
837 fuzzer::F->AnnounceOutput(Data, Size);