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-rw-r--r--tools/fuzzing/libfuzzer/FuzzerLoop.cpp901
1 files changed, 901 insertions, 0 deletions
diff --git a/tools/fuzzing/libfuzzer/FuzzerLoop.cpp b/tools/fuzzing/libfuzzer/FuzzerLoop.cpp
new file mode 100644
index 0000000000..e7dfc187db
--- /dev/null
+++ b/tools/fuzzing/libfuzzer/FuzzerLoop.cpp
@@ -0,0 +1,901 @@
+//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// Fuzzer's main loop.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCorpus.h"
+#include "FuzzerIO.h"
+#include "FuzzerInternal.h"
+#include "FuzzerMutate.h"
+#include "FuzzerPlatform.h"
+#include "FuzzerRandom.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <cstring>
+#include <memory>
+#include <mutex>
+#include <set>
+
+#if defined(__has_include)
+#if __has_include(<sanitizer / lsan_interface.h>)
+#include <sanitizer/lsan_interface.h>
+#endif
+#endif
+
+#define NO_SANITIZE_MEMORY
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+#undef NO_SANITIZE_MEMORY
+#define NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
+#endif
+#endif
+
+namespace fuzzer {
+static const size_t kMaxUnitSizeToPrint = 256;
+
+thread_local bool Fuzzer::IsMyThread;
+
+bool RunningUserCallback = false;
+
+// Only one Fuzzer per process.
+static Fuzzer *F;
+
+// Leak detection is expensive, so we first check if there were more mallocs
+// than frees (using the sanitizer malloc hooks) and only then try to call lsan.
+struct MallocFreeTracer {
+ void Start(int TraceLevel) {
+ this->TraceLevel = TraceLevel;
+ if (TraceLevel)
+ Printf("MallocFreeTracer: START\n");
+ Mallocs = 0;
+ Frees = 0;
+ }
+ // Returns true if there were more mallocs than frees.
+ bool Stop() {
+ if (TraceLevel)
+ Printf("MallocFreeTracer: STOP %zd %zd (%s)\n", Mallocs.load(),
+ Frees.load(), Mallocs == Frees ? "same" : "DIFFERENT");
+ bool Result = Mallocs > Frees;
+ Mallocs = 0;
+ Frees = 0;
+ TraceLevel = 0;
+ return Result;
+ }
+ std::atomic<size_t> Mallocs;
+ std::atomic<size_t> Frees;
+ int TraceLevel = 0;
+
+ std::recursive_mutex TraceMutex;
+ bool TraceDisabled = false;
+};
+
+static MallocFreeTracer AllocTracer;
+
+// Locks printing and avoids nested hooks triggered from mallocs/frees in
+// sanitizer.
+class TraceLock {
+public:
+ TraceLock() : Lock(AllocTracer.TraceMutex) {
+ AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled;
+ }
+ ~TraceLock() { AllocTracer.TraceDisabled = !AllocTracer.TraceDisabled; }
+
+ bool IsDisabled() const {
+ // This is already inverted value.
+ return !AllocTracer.TraceDisabled;
+ }
+
+private:
+ std::lock_guard<std::recursive_mutex> Lock;
+};
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void MallocHook(const volatile void *ptr, size_t size) {
+ size_t N = AllocTracer.Mallocs++;
+ F->HandleMalloc(size);
+ if (int TraceLevel = AllocTracer.TraceLevel) {
+ TraceLock Lock;
+ if (Lock.IsDisabled())
+ return;
+ Printf("MALLOC[%zd] %p %zd\n", N, ptr, size);
+ if (TraceLevel >= 2 && EF)
+ PrintStackTrace();
+ }
+}
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void FreeHook(const volatile void *ptr) {
+ size_t N = AllocTracer.Frees++;
+ if (int TraceLevel = AllocTracer.TraceLevel) {
+ TraceLock Lock;
+ if (Lock.IsDisabled())
+ return;
+ Printf("FREE[%zd] %p\n", N, ptr);
+ if (TraceLevel >= 2 && EF)
+ PrintStackTrace();
+ }
+}
+
+// Crash on a single malloc that exceeds the rss limit.
+void Fuzzer::HandleMalloc(size_t Size) {
+ if (!Options.MallocLimitMb || (Size >> 20) < (size_t)Options.MallocLimitMb)
+ return;
+ Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n", GetPid(),
+ Size);
+ Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
+ PrintStackTrace();
+ DumpCurrentUnit("oom-");
+ Printf("SUMMARY: libFuzzer: out-of-memory\n");
+ PrintFinalStats();
+ _Exit(Options.OOMExitCode); // Stop right now.
+}
+
+Fuzzer::Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
+ FuzzingOptions Options)
+ : CB(CB), Corpus(Corpus), MD(MD), Options(Options) {
+ if (EF->__sanitizer_set_death_callback)
+ EF->__sanitizer_set_death_callback(StaticDeathCallback);
+ assert(!F);
+ F = this;
+ TPC.ResetMaps();
+ IsMyThread = true;
+ if (Options.DetectLeaks && EF->__sanitizer_install_malloc_and_free_hooks)
+ EF->__sanitizer_install_malloc_and_free_hooks(MallocHook, FreeHook);
+ TPC.SetUseCounters(Options.UseCounters);
+ TPC.SetUseValueProfileMask(Options.UseValueProfile);
+
+ if (Options.Verbosity)
+ TPC.PrintModuleInfo();
+ if (!Options.OutputCorpus.empty() && Options.ReloadIntervalSec)
+ EpochOfLastReadOfOutputCorpus = GetEpoch(Options.OutputCorpus);
+ MaxInputLen = MaxMutationLen = Options.MaxLen;
+ TmpMaxMutationLen = 0; // Will be set once we load the corpus.
+ AllocateCurrentUnitData();
+ CurrentUnitSize = 0;
+ memset(BaseSha1, 0, sizeof(BaseSha1));
+}
+
+Fuzzer::~Fuzzer() {}
+
+void Fuzzer::AllocateCurrentUnitData() {
+ if (CurrentUnitData || MaxInputLen == 0)
+ return;
+ CurrentUnitData = new uint8_t[MaxInputLen];
+}
+
+void Fuzzer::StaticDeathCallback() {
+ assert(F);
+ F->DeathCallback();
+}
+
+void Fuzzer::DumpCurrentUnit(const char *Prefix) {
+ if (!CurrentUnitData)
+ return; // Happens when running individual inputs.
+ ScopedDisableMsanInterceptorChecks S;
+ MD.PrintMutationSequence();
+ Printf("; base unit: %s\n", Sha1ToString(BaseSha1).c_str());
+ size_t UnitSize = CurrentUnitSize;
+ if (UnitSize <= kMaxUnitSizeToPrint) {
+ PrintHexArray(CurrentUnitData, UnitSize, "\n");
+ PrintASCII(CurrentUnitData, UnitSize, "\n");
+ }
+ WriteUnitToFileWithPrefix({CurrentUnitData, CurrentUnitData + UnitSize},
+ Prefix);
+}
+
+NO_SANITIZE_MEMORY
+void Fuzzer::DeathCallback() {
+ DumpCurrentUnit("crash-");
+ PrintFinalStats();
+}
+
+void Fuzzer::StaticAlarmCallback() {
+ assert(F);
+ F->AlarmCallback();
+}
+
+void Fuzzer::StaticCrashSignalCallback() {
+ assert(F);
+ F->CrashCallback();
+}
+
+void Fuzzer::StaticExitCallback() {
+ assert(F);
+ F->ExitCallback();
+}
+
+void Fuzzer::StaticInterruptCallback() {
+ assert(F);
+ F->InterruptCallback();
+}
+
+void Fuzzer::StaticGracefulExitCallback() {
+ assert(F);
+ F->GracefulExitRequested = true;
+ Printf("INFO: signal received, trying to exit gracefully\n");
+}
+
+void Fuzzer::StaticFileSizeExceedCallback() {
+ Printf("==%lu== ERROR: libFuzzer: file size exceeded\n", GetPid());
+ exit(1);
+}
+
+void Fuzzer::CrashCallback() {
+ if (EF->__sanitizer_acquire_crash_state &&
+ !EF->__sanitizer_acquire_crash_state())
+ return;
+ Printf("==%lu== ERROR: libFuzzer: deadly signal\n", GetPid());
+ PrintStackTrace();
+ Printf("NOTE: libFuzzer has rudimentary signal handlers.\n"
+ " Combine libFuzzer with AddressSanitizer or similar for better "
+ "crash reports.\n");
+ Printf("SUMMARY: libFuzzer: deadly signal\n");
+ DumpCurrentUnit("crash-");
+ PrintFinalStats();
+ _Exit(Options.ErrorExitCode); // Stop right now.
+}
+
+void Fuzzer::ExitCallback() {
+ if (!RunningUserCallback)
+ return; // This exit did not come from the user callback
+ if (EF->__sanitizer_acquire_crash_state &&
+ !EF->__sanitizer_acquire_crash_state())
+ return;
+ Printf("==%lu== ERROR: libFuzzer: fuzz target exited\n", GetPid());
+ PrintStackTrace();
+ Printf("SUMMARY: libFuzzer: fuzz target exited\n");
+ DumpCurrentUnit("crash-");
+ PrintFinalStats();
+ _Exit(Options.ErrorExitCode);
+}
+
+bool Fuzzer::MaybeExitGracefully() {
+ if (!F->GracefulExitRequested) return false;
+ Printf("==%lu== INFO: libFuzzer: exiting as requested\n", GetPid());
+ RmDirRecursive(TempPath("FuzzWithFork", ".dir"));
+ F->PrintFinalStats();
+ return true;
+}
+
+void Fuzzer::GracefullyExit() {
+ F->GracefulExitRequested = true;
+}
+
+bool Fuzzer::isGracefulExitRequested() {
+ return F->GracefulExitRequested;
+}
+
+void Fuzzer::InterruptCallback() {
+ Printf("==%lu== libFuzzer: run interrupted; exiting\n", GetPid());
+ PrintFinalStats();
+ ScopedDisableMsanInterceptorChecks S; // RmDirRecursive may call opendir().
+ RmDirRecursive(TempPath("FuzzWithFork", ".dir"));
+ // Stop right now, don't perform any at-exit actions.
+ _Exit(Options.InterruptExitCode);
+}
+
+NO_SANITIZE_MEMORY
+void Fuzzer::AlarmCallback() {
+ assert(Options.UnitTimeoutSec > 0);
+ // In Windows and Fuchsia, Alarm callback is executed by a different thread.
+ // NetBSD's current behavior needs this change too.
+#if !LIBFUZZER_WINDOWS && !LIBFUZZER_NETBSD && !LIBFUZZER_FUCHSIA
+ if (!InFuzzingThread())
+ return;
+#endif
+ if (!RunningUserCallback)
+ return; // We have not started running units yet.
+ 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) {
+ if (EF->__sanitizer_acquire_crash_state &&
+ !EF->__sanitizer_acquire_crash_state())
+ return;
+ 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);
+ DumpCurrentUnit("timeout-");
+ Printf("==%lu== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
+ Seconds);
+ PrintStackTrace();
+ Printf("SUMMARY: libFuzzer: timeout\n");
+ PrintFinalStats();
+ _Exit(Options.TimeoutExitCode); // Stop right now.
+ }
+}
+
+void Fuzzer::RssLimitCallback() {
+ if (EF->__sanitizer_acquire_crash_state &&
+ !EF->__sanitizer_acquire_crash_state())
+ return;
+ Printf(
+ "==%lu== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
+ GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
+ Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
+ PrintMemoryProfile();
+ DumpCurrentUnit("oom-");
+ Printf("SUMMARY: libFuzzer: out-of-memory\n");
+ PrintFinalStats();
+ _Exit(Options.OOMExitCode); // Stop right now.
+}
+
+void Fuzzer::PrintStats(const char *Where, const char *End, size_t Units,
+ size_t Features) {
+ size_t ExecPerSec = execPerSec();
+ if (!Options.Verbosity)
+ return;
+ Printf("#%zd\t%s", TotalNumberOfRuns, Where);
+ if (size_t N = TPC.GetTotalPCCoverage())
+ Printf(" cov: %zd", N);
+ if (size_t N = Features ? Features : Corpus.NumFeatures())
+ Printf(" ft: %zd", N);
+ if (!Corpus.empty()) {
+ Printf(" corp: %zd", Corpus.NumActiveUnits());
+ if (size_t N = Corpus.SizeInBytes()) {
+ if (N < (1 << 14))
+ Printf("/%zdb", N);
+ else if (N < (1 << 24))
+ Printf("/%zdKb", N >> 10);
+ else
+ Printf("/%zdMb", N >> 20);
+ }
+ if (size_t FF = Corpus.NumInputsThatTouchFocusFunction())
+ Printf(" focus: %zd", FF);
+ }
+ if (TmpMaxMutationLen)
+ Printf(" lim: %zd", TmpMaxMutationLen);
+ if (Units)
+ Printf(" units: %zd", Units);
+
+ Printf(" exec/s: %zd", ExecPerSec);
+ Printf(" rss: %zdMb", GetPeakRSSMb());
+ Printf("%s", End);
+}
+
+void Fuzzer::PrintFinalStats() {
+ if (Options.PrintCoverage)
+ TPC.PrintCoverage();
+ if (Options.PrintCorpusStats)
+ Corpus.PrintStats();
+ if (!Options.PrintFinalStats)
+ return;
+ size_t ExecPerSec = execPerSec();
+ Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
+ Printf("stat::average_exec_per_sec: %zd\n", ExecPerSec);
+ Printf("stat::new_units_added: %zd\n", NumberOfNewUnitsAdded);
+ Printf("stat::slowest_unit_time_sec: %zd\n", TimeOfLongestUnitInSeconds);
+ Printf("stat::peak_rss_mb: %zd\n", GetPeakRSSMb());
+}
+
+void Fuzzer::SetMaxInputLen(size_t MaxInputLen) {
+ assert(this->MaxInputLen == 0); // Can only reset MaxInputLen from 0 to non-0.
+ assert(MaxInputLen);
+ this->MaxInputLen = MaxInputLen;
+ this->MaxMutationLen = MaxInputLen;
+ AllocateCurrentUnitData();
+ Printf("INFO: -max_len is not provided; "
+ "libFuzzer will not generate inputs larger than %zd bytes\n",
+ MaxInputLen);
+}
+
+void Fuzzer::SetMaxMutationLen(size_t MaxMutationLen) {
+ assert(MaxMutationLen && MaxMutationLen <= MaxInputLen);
+ this->MaxMutationLen = MaxMutationLen;
+}
+
+void Fuzzer::CheckExitOnSrcPosOrItem() {
+ if (!Options.ExitOnSrcPos.empty()) {
+ static auto *PCsSet = new Set<uintptr_t>;
+ auto HandlePC = [&](const TracePC::PCTableEntry *TE) {
+ if (!PCsSet->insert(TE->PC).second)
+ return;
+ std::string Descr = DescribePC("%F %L", TE->PC + 1);
+ if (Descr.find(Options.ExitOnSrcPos) != std::string::npos) {
+ Printf("INFO: found line matching '%s', exiting.\n",
+ Options.ExitOnSrcPos.c_str());
+ _Exit(0);
+ }
+ };
+ TPC.ForEachObservedPC(HandlePC);
+ }
+ if (!Options.ExitOnItem.empty()) {
+ if (Corpus.HasUnit(Options.ExitOnItem)) {
+ Printf("INFO: found item with checksum '%s', exiting.\n",
+ Options.ExitOnItem.c_str());
+ _Exit(0);
+ }
+ }
+}
+
+void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
+ if (Options.OutputCorpus.empty() || !Options.ReloadIntervalSec)
+ return;
+ Vector<Unit> AdditionalCorpus;
+ ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
+ &EpochOfLastReadOfOutputCorpus, MaxSize,
+ /*ExitOnError*/ false);
+ if (Options.Verbosity >= 2)
+ Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
+ bool Reloaded = false;
+ for (auto &U : AdditionalCorpus) {
+ if (U.size() > MaxSize)
+ U.resize(MaxSize);
+ if (!Corpus.HasUnit(U)) {
+ if (RunOne(U.data(), U.size())) {
+ CheckExitOnSrcPosOrItem();
+ Reloaded = true;
+ }
+ }
+ }
+ if (Reloaded)
+ PrintStats("RELOAD");
+}
+
+void Fuzzer::PrintPulseAndReportSlowInput(const uint8_t *Data, size_t Size) {
+ auto TimeOfUnit =
+ duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
+ if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
+ secondsSinceProcessStartUp() >= 2)
+ PrintStats("pulse ");
+ if (TimeOfUnit > TimeOfLongestUnitInSeconds * 1.1 &&
+ TimeOfUnit >= Options.ReportSlowUnits) {
+ TimeOfLongestUnitInSeconds = TimeOfUnit;
+ Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
+ WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
+ }
+}
+
+static void WriteFeatureSetToFile(const std::string &FeaturesDir,
+ const std::string &FileName,
+ const Vector<uint32_t> &FeatureSet) {
+ if (FeaturesDir.empty() || FeatureSet.empty()) return;
+ WriteToFile(reinterpret_cast<const uint8_t *>(FeatureSet.data()),
+ FeatureSet.size() * sizeof(FeatureSet[0]),
+ DirPlusFile(FeaturesDir, FileName));
+}
+
+static void RenameFeatureSetFile(const std::string &FeaturesDir,
+ const std::string &OldFile,
+ const std::string &NewFile) {
+ if (FeaturesDir.empty()) return;
+ RenameFile(DirPlusFile(FeaturesDir, OldFile),
+ DirPlusFile(FeaturesDir, NewFile));
+}
+
+bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
+ InputInfo *II, bool *FoundUniqFeatures) {
+ if (!Size)
+ return false;
+
+ if (ExecuteCallback(Data, Size) > 0) {
+ return false;
+ }
+
+ UniqFeatureSetTmp.clear();
+ size_t FoundUniqFeaturesOfII = 0;
+ size_t NumUpdatesBefore = Corpus.NumFeatureUpdates();
+ TPC.CollectFeatures([&](size_t Feature) {
+ if (Corpus.AddFeature(Feature, Size, Options.Shrink))
+ UniqFeatureSetTmp.push_back(Feature);
+ if (Options.Entropic)
+ Corpus.UpdateFeatureFrequency(II, Feature);
+ if (Options.ReduceInputs && II)
+ if (std::binary_search(II->UniqFeatureSet.begin(),
+ II->UniqFeatureSet.end(), Feature))
+ FoundUniqFeaturesOfII++;
+ });
+ if (FoundUniqFeatures)
+ *FoundUniqFeatures = FoundUniqFeaturesOfII;
+ PrintPulseAndReportSlowInput(Data, Size);
+ size_t NumNewFeatures = Corpus.NumFeatureUpdates() - NumUpdatesBefore;
+ if (NumNewFeatures) {
+ TPC.UpdateObservedPCs();
+ auto NewII = Corpus.AddToCorpus({Data, Data + Size}, NumNewFeatures,
+ MayDeleteFile, TPC.ObservedFocusFunction(),
+ UniqFeatureSetTmp, DFT, II);
+ WriteFeatureSetToFile(Options.FeaturesDir, Sha1ToString(NewII->Sha1),
+ NewII->UniqFeatureSet);
+ return true;
+ }
+ if (II && FoundUniqFeaturesOfII &&
+ II->DataFlowTraceForFocusFunction.empty() &&
+ FoundUniqFeaturesOfII == II->UniqFeatureSet.size() &&
+ II->U.size() > Size) {
+ auto OldFeaturesFile = Sha1ToString(II->Sha1);
+ Corpus.Replace(II, {Data, Data + Size});
+ RenameFeatureSetFile(Options.FeaturesDir, OldFeaturesFile,
+ Sha1ToString(II->Sha1));
+ return true;
+ }
+ return false;
+}
+
+size_t Fuzzer::GetCurrentUnitInFuzzingThead(const uint8_t **Data) const {
+ assert(InFuzzingThread());
+ *Data = CurrentUnitData;
+ return CurrentUnitSize;
+}
+
+void Fuzzer::CrashOnOverwrittenData() {
+ Printf("==%d== ERROR: libFuzzer: fuzz target overwrites its const input\n",
+ GetPid());
+ PrintStackTrace();
+ Printf("SUMMARY: libFuzzer: overwrites-const-input\n");
+ DumpCurrentUnit("crash-");
+ PrintFinalStats();
+ _Exit(Options.ErrorExitCode); // Stop right now.
+}
+
+// Compare two arrays, but not all bytes if the arrays are large.
+static bool LooseMemeq(const uint8_t *A, const uint8_t *B, size_t Size) {
+ const size_t Limit = 64;
+ if (Size <= 64)
+ return !memcmp(A, B, Size);
+ // Compare first and last Limit/2 bytes.
+ return !memcmp(A, B, Limit / 2) &&
+ !memcmp(A + Size - Limit / 2, B + Size - Limit / 2, Limit / 2);
+}
+
+int Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
+ TPC.RecordInitialStack();
+ TotalNumberOfRuns++;
+ assert(InFuzzingThread());
+ // We copy the contents of Unit into a separate heap buffer
+ // so that we reliably find buffer overflows in it.
+ uint8_t *DataCopy = new uint8_t[Size];
+ memcpy(DataCopy, Data, Size);
+ if (EF->__msan_unpoison)
+ EF->__msan_unpoison(DataCopy, Size);
+ if (EF->__msan_unpoison_param)
+ EF->__msan_unpoison_param(2);
+ if (CurrentUnitData && CurrentUnitData != Data)
+ memcpy(CurrentUnitData, Data, Size);
+ CurrentUnitSize = Size;
+ int Res = 0;
+ {
+ ScopedEnableMsanInterceptorChecks S;
+ AllocTracer.Start(Options.TraceMalloc);
+ UnitStartTime = system_clock::now();
+ TPC.ResetMaps();
+ RunningUserCallback = true;
+ Res = CB(DataCopy, Size);
+ RunningUserCallback = false;
+ UnitStopTime = system_clock::now();
+ assert(Res >= 0);
+ HasMoreMallocsThanFrees = AllocTracer.Stop();
+ }
+ if (!LooseMemeq(DataCopy, Data, Size))
+ CrashOnOverwrittenData();
+ CurrentUnitSize = 0;
+ delete[] DataCopy;
+ return Res;
+}
+
+std::string Fuzzer::WriteToOutputCorpus(const Unit &U) {
+ if (Options.OnlyASCII)
+ assert(IsASCII(U));
+ if (Options.OutputCorpus.empty())
+ return "";
+ std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
+ WriteToFile(U, Path);
+ if (Options.Verbosity >= 2)
+ Printf("Written %zd bytes to %s\n", U.size(), Path.c_str());
+ return Path;
+}
+
+void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
+ if (!Options.SaveArtifacts)
+ return;
+ std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
+ if (!Options.ExactArtifactPath.empty())
+ Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
+ WriteToFile(U, Path);
+ Printf("artifact_prefix='%s'; Test unit written to %s\n",
+ Options.ArtifactPrefix.c_str(), Path.c_str());
+ if (U.size() <= kMaxUnitSizeToPrint)
+ Printf("Base64: %s\n", Base64(U).c_str());
+}
+
+void Fuzzer::PrintStatusForNewUnit(const Unit &U, const char *Text) {
+ if (!Options.PrintNEW)
+ return;
+ PrintStats(Text, "");
+ if (Options.Verbosity) {
+ Printf(" L: %zd/%zd ", U.size(), Corpus.MaxInputSize());
+ MD.PrintMutationSequence();
+ Printf("\n");
+ }
+}
+
+void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
+ II->NumSuccessfullMutations++;
+ MD.RecordSuccessfulMutationSequence();
+ PrintStatusForNewUnit(U, II->Reduced ? "REDUCE" : "NEW ");
+ WriteToOutputCorpus(U);
+ NumberOfNewUnitsAdded++;
+ CheckExitOnSrcPosOrItem(); // Check only after the unit is saved to corpus.
+ LastCorpusUpdateRun = TotalNumberOfRuns;
+}
+
+// Tries detecting a memory leak on the particular input that we have just
+// executed before calling this function.
+void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
+ bool DuringInitialCorpusExecution) {
+ if (!HasMoreMallocsThanFrees)
+ return; // mallocs==frees, a leak is unlikely.
+ if (!Options.DetectLeaks)
+ return;
+ if (!DuringInitialCorpusExecution &&
+ TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+ return;
+ if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
+ !(EF->__lsan_do_recoverable_leak_check))
+ return; // No lsan.
+ // Run the target once again, but with lsan disabled so that if there is
+ // a real leak we do not report it twice.
+ EF->__lsan_disable();
+ ExecuteCallback(Data, Size);
+ EF->__lsan_enable();
+ if (!HasMoreMallocsThanFrees)
+ return; // a leak is unlikely.
+ if (NumberOfLeakDetectionAttempts++ > 1000) {
+ Options.DetectLeaks = false;
+ Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
+ " Most likely the target function accumulates allocated\n"
+ " memory in a global state w/o actually leaking it.\n"
+ " You may try running this binary with -trace_malloc=[12]"
+ " to get a trace of mallocs and frees.\n"
+ " If LeakSanitizer is enabled in this process it will still\n"
+ " run on the process shutdown.\n");
+ return;
+ }
+ // Now perform the actual lsan pass. This is expensive and we must ensure
+ // we don't call it too often.
+ if (EF->__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
+ if (DuringInitialCorpusExecution)
+ Printf("\nINFO: a leak has been found in the initial corpus.\n\n");
+ Printf("INFO: to ignore leaks on libFuzzer side use -detect_leaks=0.\n\n");
+ CurrentUnitSize = Size;
+ DumpCurrentUnit("leak-");
+ PrintFinalStats();
+ _Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
+ }
+}
+
+bool Fuzzer::MutateAndTestOne() {
+ MD.StartMutationSequence();
+
+ auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
+ if (Options.DoCrossOver)
+ MD.SetCrossOverWith(&Corpus.ChooseUnitToMutate(MD.GetRand()).U);
+ const auto &U = II.U;
+ memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
+ assert(CurrentUnitData);
+ size_t Size = U.size();
+ assert(Size <= MaxInputLen && "Oversized Unit");
+ memcpy(CurrentUnitData, U.data(), Size);
+
+ assert(MaxMutationLen > 0);
+
+ size_t CurrentMaxMutationLen =
+ Min(MaxMutationLen, Max(U.size(), TmpMaxMutationLen));
+ assert(CurrentMaxMutationLen > 0);
+
+ for (int i = 0; i < Options.MutateDepth; i++) {
+ if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+ break;
+ if (MaybeExitGracefully()) return true;
+ size_t NewSize = 0;
+ if (II.HasFocusFunction && !II.DataFlowTraceForFocusFunction.empty() &&
+ Size <= CurrentMaxMutationLen)
+ NewSize = MD.MutateWithMask(CurrentUnitData, Size, Size,
+ II.DataFlowTraceForFocusFunction);
+
+ // If MutateWithMask either failed or wasn't called, call default Mutate.
+ if (!NewSize)
+ NewSize = MD.Mutate(CurrentUnitData, Size, CurrentMaxMutationLen);
+
+ if (!NewSize)
+ continue;
+
+ assert(NewSize > 0 && "Mutator returned empty unit");
+ assert(NewSize <= CurrentMaxMutationLen && "Mutator return oversized unit");
+ Size = NewSize;
+ II.NumExecutedMutations++;
+ Corpus.IncrementNumExecutedMutations();
+
+ bool FoundUniqFeatures = false;
+ bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II,
+ &FoundUniqFeatures);
+ TryDetectingAMemoryLeak(CurrentUnitData, Size,
+ /*DuringInitialCorpusExecution*/ false);
+ if (NewCov) {
+ ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
+ break; // We will mutate this input more in the next rounds.
+ }
+ if (Options.ReduceDepth && !FoundUniqFeatures)
+ break;
+ }
+
+ II.NeedsEnergyUpdate = true;
+ return false;
+}
+
+void Fuzzer::PurgeAllocator() {
+ if (Options.PurgeAllocatorIntervalSec < 0 || !EF->__sanitizer_purge_allocator)
+ return;
+ if (duration_cast<seconds>(system_clock::now() -
+ LastAllocatorPurgeAttemptTime)
+ .count() < Options.PurgeAllocatorIntervalSec)
+ return;
+
+ if (Options.RssLimitMb <= 0 ||
+ GetPeakRSSMb() > static_cast<size_t>(Options.RssLimitMb) / 2)
+ EF->__sanitizer_purge_allocator();
+
+ LastAllocatorPurgeAttemptTime = system_clock::now();
+}
+
+int Fuzzer::ReadAndExecuteSeedCorpora(Vector<SizedFile> &CorporaFiles) {
+ const size_t kMaxSaneLen = 1 << 20;
+ const size_t kMinDefaultLen = 4096;
+ size_t MaxSize = 0;
+ size_t MinSize = -1;
+ size_t TotalSize = 0;
+ for (auto &File : CorporaFiles) {
+ MaxSize = Max(File.Size, MaxSize);
+ MinSize = Min(File.Size, MinSize);
+ TotalSize += File.Size;
+ }
+ if (Options.MaxLen == 0)
+ SetMaxInputLen(std::min(std::max(kMinDefaultLen, MaxSize), kMaxSaneLen));
+ assert(MaxInputLen > 0);
+
+ // Test the callback with empty input and never try it again.
+ uint8_t dummy = 0;
+ ExecuteCallback(&dummy, 0);
+
+ if (CorporaFiles.empty()) {
+ Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
+ Unit U({'\n'}); // Valid ASCII input.
+ RunOne(U.data(), U.size());
+ } else {
+ Printf("INFO: seed corpus: files: %zd min: %zdb max: %zdb total: %zdb"
+ " rss: %zdMb\n",
+ CorporaFiles.size(), MinSize, MaxSize, TotalSize, GetPeakRSSMb());
+ if (Options.ShuffleAtStartUp)
+ std::shuffle(CorporaFiles.begin(), CorporaFiles.end(), MD.GetRand());
+
+ if (Options.PreferSmall) {
+ std::stable_sort(CorporaFiles.begin(), CorporaFiles.end());
+ assert(CorporaFiles.front().Size <= CorporaFiles.back().Size);
+ }
+
+ // Load and execute inputs one by one.
+ for (auto &SF : CorporaFiles) {
+ auto U = FileToVector(SF.File, MaxInputLen, /*ExitOnError=*/false);
+ assert(U.size() <= MaxInputLen);
+ RunOne(U.data(), U.size());
+ CheckExitOnSrcPosOrItem();
+ TryDetectingAMemoryLeak(U.data(), U.size(),
+ /*DuringInitialCorpusExecution*/ true);
+ }
+ }
+
+ PrintStats("INITED");
+ if (!Options.FocusFunction.empty()) {
+ Printf("INFO: %zd/%zd inputs touch the focus function\n",
+ Corpus.NumInputsThatTouchFocusFunction(), Corpus.size());
+ if (!Options.DataFlowTrace.empty())
+ Printf("INFO: %zd/%zd inputs have the Data Flow Trace\n",
+ Corpus.NumInputsWithDataFlowTrace(),
+ Corpus.NumInputsThatTouchFocusFunction());
+ }
+
+ if (Corpus.empty() && Options.MaxNumberOfRuns) {
+ Printf("ERROR: no interesting inputs were found. "
+ "Is the code instrumented for coverage? Exiting.\n");
+ return 1;
+ }
+ return 0;
+}
+
+int Fuzzer::Loop(Vector<SizedFile> &CorporaFiles) {
+ auto FocusFunctionOrAuto = Options.FocusFunction;
+ int Res = DFT.Init(Options.DataFlowTrace, &FocusFunctionOrAuto, CorporaFiles,
+ MD.GetRand());
+ if (Res != 0)
+ return Res;
+ Res = TPC.SetFocusFunction(FocusFunctionOrAuto);
+ if (Res != 0)
+ return Res;
+ Res = ReadAndExecuteSeedCorpora(CorporaFiles);
+ if (Res != 0)
+ return Res;
+ DFT.Clear(); // No need for DFT any more.
+ TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
+ TPC.SetPrintNewFuncs(Options.PrintNewCovFuncs);
+ system_clock::time_point LastCorpusReload = system_clock::now();
+
+ TmpMaxMutationLen =
+ Min(MaxMutationLen, Max(size_t(4), Corpus.MaxInputSize()));
+
+ while (true) {
+ auto Now = system_clock::now();
+ if (!Options.StopFile.empty() &&
+ !FileToVector(Options.StopFile, 1, false).empty())
+ break;
+ if (duration_cast<seconds>(Now - LastCorpusReload).count() >=
+ Options.ReloadIntervalSec) {
+ RereadOutputCorpus(MaxInputLen);
+ LastCorpusReload = system_clock::now();
+ }
+ if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+ break;
+ if (TimedOut())
+ break;
+
+ // Update TmpMaxMutationLen
+ if (Options.LenControl) {
+ if (TmpMaxMutationLen < MaxMutationLen &&
+ TotalNumberOfRuns - LastCorpusUpdateRun >
+ Options.LenControl * Log(TmpMaxMutationLen)) {
+ TmpMaxMutationLen =
+ Min(MaxMutationLen, TmpMaxMutationLen + Log(TmpMaxMutationLen));
+ LastCorpusUpdateRun = TotalNumberOfRuns;
+ }
+ } else {
+ TmpMaxMutationLen = MaxMutationLen;
+ }
+
+ // Perform several mutations and runs.
+ if (MutateAndTestOne())
+ return 0;
+
+ PurgeAllocator();
+ }
+
+ PrintStats("DONE ", "\n");
+ MD.PrintRecommendedDictionary();
+ return 0;
+}
+
+void Fuzzer::MinimizeCrashLoop(const Unit &U) {
+ if (U.size() <= 1)
+ return;
+ while (!TimedOut() && TotalNumberOfRuns < Options.MaxNumberOfRuns) {
+ MD.StartMutationSequence();
+ memcpy(CurrentUnitData, U.data(), U.size());
+ for (int i = 0; i < Options.MutateDepth; i++) {
+ size_t NewSize = MD.Mutate(CurrentUnitData, U.size(), MaxMutationLen);
+ assert(NewSize <= MaxMutationLen);
+ if (!NewSize)
+ continue;
+ ExecuteCallback(CurrentUnitData, NewSize);
+ PrintPulseAndReportSlowInput(CurrentUnitData, NewSize);
+ TryDetectingAMemoryLeak(CurrentUnitData, NewSize,
+ /*DuringInitialCorpusExecution*/ false);
+ }
+ }
+}
+
+} // namespace fuzzer
+
+extern "C" {
+
+ATTRIBUTE_INTERFACE size_t
+LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+ assert(fuzzer::F);
+ return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
+}
+
+} // extern "C"
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