forked from OSchip/llvm-project
698 lines
22 KiB
C++
698 lines
22 KiB
C++
//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
// Fuzzer's main loop.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "FuzzerInternal.h"
|
|
#include <algorithm>
|
|
#include <cstring>
|
|
#include <memory>
|
|
|
|
#if defined(__has_include)
|
|
#if __has_include(<sanitizer / coverage_interface.h>)
|
|
#include <sanitizer/coverage_interface.h>
|
|
#endif
|
|
#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
|
|
|
|
extern "C" {
|
|
// Re-declare some of the sanitizer functions as "weak" so that
|
|
// libFuzzer can be linked w/o the sanitizers and sanitizer-coverage
|
|
// (in which case it will complain at start-up time).
|
|
__attribute__((weak)) void __sanitizer_print_stack_trace();
|
|
__attribute__((weak)) void __sanitizer_reset_coverage();
|
|
__attribute__((weak)) size_t __sanitizer_get_total_unique_caller_callee_pairs();
|
|
__attribute__((weak)) size_t __sanitizer_get_total_unique_coverage();
|
|
__attribute__((weak)) void
|
|
__sanitizer_set_death_callback(void (*callback)(void));
|
|
__attribute__((weak)) size_t __sanitizer_get_number_of_counters();
|
|
__attribute__((weak)) uintptr_t
|
|
__sanitizer_update_counter_bitset_and_clear_counters(uint8_t *bitset);
|
|
__attribute__((weak)) uintptr_t
|
|
__sanitizer_get_coverage_pc_buffer(uintptr_t **data);
|
|
|
|
__attribute__((weak)) size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
|
|
size_t MaxSize,
|
|
unsigned int Seed);
|
|
__attribute__((weak)) void __sanitizer_malloc_hook(void *ptr, size_t size);
|
|
__attribute__((weak)) void __sanitizer_free_hook(void *ptr);
|
|
__attribute__((weak)) void __lsan_enable();
|
|
__attribute__((weak)) void __lsan_disable();
|
|
__attribute__((weak)) int __lsan_do_recoverable_leak_check();
|
|
}
|
|
|
|
namespace fuzzer {
|
|
static const size_t kMaxUnitSizeToPrint = 256;
|
|
|
|
static void MissingWeakApiFunction(const char *FnName) {
|
|
Printf("ERROR: %s is not defined. Exiting.\n"
|
|
"Did you use -fsanitize-coverage=... to build your code?\n",
|
|
FnName);
|
|
exit(1);
|
|
}
|
|
|
|
#define CHECK_WEAK_API_FUNCTION(fn) \
|
|
do { \
|
|
if (!fn) \
|
|
MissingWeakApiFunction(#fn); \
|
|
} while (false)
|
|
|
|
// Only one Fuzzer per process.
|
|
static Fuzzer *F;
|
|
|
|
size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
|
|
assert(F);
|
|
return F->GetMD().Mutate(Data, Size, MaxSize);
|
|
}
|
|
|
|
Fuzzer::Fuzzer(UserCallback CB, MutationDispatcher &MD, FuzzingOptions Options)
|
|
: CB(CB), MD(MD), Options(Options) {
|
|
SetDeathCallback();
|
|
InitializeTraceState();
|
|
assert(!F);
|
|
F = this;
|
|
}
|
|
|
|
void Fuzzer::SetDeathCallback() {
|
|
CHECK_WEAK_API_FUNCTION(__sanitizer_set_death_callback);
|
|
__sanitizer_set_death_callback(StaticDeathCallback);
|
|
}
|
|
|
|
void Fuzzer::StaticDeathCallback() {
|
|
assert(F);
|
|
F->DeathCallback();
|
|
}
|
|
|
|
void Fuzzer::DumpCurrentUnit(const char *Prefix) {
|
|
if (CurrentUnitSize <= kMaxUnitSizeToPrint) {
|
|
PrintHexArray(CurrentUnitData, CurrentUnitSize, "\n");
|
|
PrintASCII(CurrentUnitData, CurrentUnitSize, "\n");
|
|
}
|
|
WriteUnitToFileWithPrefix(
|
|
{CurrentUnitData, CurrentUnitData + CurrentUnitSize}, Prefix);
|
|
}
|
|
|
|
NO_SANITIZE_MEMORY
|
|
void Fuzzer::DeathCallback() {
|
|
if (!CurrentUnitSize) return;
|
|
Printf("DEATH:\n");
|
|
DumpCurrentUnit("crash-");
|
|
PrintFinalStats();
|
|
}
|
|
|
|
void Fuzzer::StaticAlarmCallback() {
|
|
assert(F);
|
|
F->AlarmCallback();
|
|
}
|
|
|
|
void Fuzzer::StaticCrashSignalCallback() {
|
|
assert(F);
|
|
F->CrashCallback();
|
|
}
|
|
|
|
void Fuzzer::StaticInterruptCallback() {
|
|
assert(F);
|
|
F->InterruptCallback();
|
|
}
|
|
|
|
void Fuzzer::CrashCallback() {
|
|
Printf("==%d== ERROR: libFuzzer: deadly signal\n", GetPid());
|
|
if (__sanitizer_print_stack_trace)
|
|
__sanitizer_print_stack_trace();
|
|
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);
|
|
}
|
|
|
|
void Fuzzer::InterruptCallback() {
|
|
Printf("==%d== libFuzzer: run interrupted; exiting\n", GetPid());
|
|
PrintFinalStats();
|
|
_Exit(0); // Stop right now, don't perform any at-exit actions.
|
|
}
|
|
|
|
NO_SANITIZE_MEMORY
|
|
void Fuzzer::AlarmCallback() {
|
|
assert(Options.UnitTimeoutSec > 0);
|
|
if (!CurrentUnitSize)
|
|
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) {
|
|
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("==%d== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
|
|
Seconds);
|
|
if (__sanitizer_print_stack_trace)
|
|
__sanitizer_print_stack_trace();
|
|
Printf("SUMMARY: libFuzzer: timeout\n");
|
|
PrintFinalStats();
|
|
_Exit(Options.TimeoutExitCode); // Stop right now.
|
|
}
|
|
}
|
|
|
|
void Fuzzer::PrintStats(const char *Where, const char *End) {
|
|
size_t ExecPerSec = execPerSec();
|
|
if (Options.OutputCSV) {
|
|
static bool csvHeaderPrinted = false;
|
|
if (!csvHeaderPrinted) {
|
|
csvHeaderPrinted = true;
|
|
Printf("runs,block_cov,bits,cc_cov,corpus,execs_per_sec,tbms,reason\n");
|
|
}
|
|
Printf("%zd,%zd,%zd,%zd,%zd,%zd,%s\n", TotalNumberOfRuns,
|
|
LastRecordedBlockCoverage, TotalBits(),
|
|
LastRecordedCallerCalleeCoverage, Corpus.size(), ExecPerSec,
|
|
Where);
|
|
}
|
|
|
|
if (!Options.Verbosity)
|
|
return;
|
|
Printf("#%zd\t%s", TotalNumberOfRuns, Where);
|
|
if (LastRecordedBlockCoverage)
|
|
Printf(" cov: %zd", LastRecordedBlockCoverage);
|
|
if (LastRecordedPcMapSize)
|
|
Printf(" path: %zd", LastRecordedPcMapSize);
|
|
if (auto TB = TotalBits())
|
|
Printf(" bits: %zd", TB);
|
|
if (LastRecordedCallerCalleeCoverage)
|
|
Printf(" indir: %zd", LastRecordedCallerCalleeCoverage);
|
|
Printf(" units: %zd exec/s: %zd", Corpus.size(), ExecPerSec);
|
|
Printf("%s", End);
|
|
}
|
|
|
|
void Fuzzer::PrintFinalStats() {
|
|
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());
|
|
}
|
|
|
|
size_t Fuzzer::MaxUnitSizeInCorpus() const {
|
|
size_t Res = 0;
|
|
for (auto &X : Corpus)
|
|
Res = std::max(Res, X.size());
|
|
return Res;
|
|
}
|
|
|
|
void Fuzzer::SetMaxLen(size_t MaxLen) {
|
|
assert(Options.MaxLen == 0); // Can only reset MaxLen from 0 to non-0.
|
|
assert(MaxLen);
|
|
Options.MaxLen = MaxLen;
|
|
Printf("INFO: -max_len is not provided, using %zd\n", Options.MaxLen);
|
|
}
|
|
|
|
|
|
void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
|
|
if (Options.OutputCorpus.empty())
|
|
return;
|
|
std::vector<Unit> AdditionalCorpus;
|
|
ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
|
|
&EpochOfLastReadOfOutputCorpus, MaxSize);
|
|
if (Corpus.empty()) {
|
|
Corpus = AdditionalCorpus;
|
|
return;
|
|
}
|
|
if (!Options.Reload)
|
|
return;
|
|
if (Options.Verbosity >= 2)
|
|
Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
|
|
for (auto &X : AdditionalCorpus) {
|
|
if (X.size() > MaxSize)
|
|
X.resize(MaxSize);
|
|
if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
|
|
if (RunOne(X)) {
|
|
Corpus.push_back(X);
|
|
UpdateCorpusDistribution();
|
|
PrintStats("RELOAD");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void Fuzzer::ShuffleCorpus(UnitVector *V) {
|
|
std::random_shuffle(V->begin(), V->end(), MD.GetRand());
|
|
if (Options.PreferSmall)
|
|
std::stable_sort(V->begin(), V->end(), [](const Unit &A, const Unit &B) {
|
|
return A.size() < B.size();
|
|
});
|
|
}
|
|
|
|
void Fuzzer::ShuffleAndMinimize() {
|
|
PrintStats("READ ");
|
|
std::vector<Unit> NewCorpus;
|
|
if (Options.ShuffleAtStartUp)
|
|
ShuffleCorpus(&Corpus);
|
|
|
|
for (const auto &U : Corpus) {
|
|
if (RunOne(U)) {
|
|
NewCorpus.push_back(U);
|
|
if (Options.Verbosity >= 2)
|
|
Printf("NEW0: %zd L %zd\n", LastRecordedBlockCoverage, U.size());
|
|
}
|
|
}
|
|
Corpus = NewCorpus;
|
|
UpdateCorpusDistribution();
|
|
for (auto &X : Corpus)
|
|
UnitHashesAddedToCorpus.insert(Hash(X));
|
|
PrintStats("INITED");
|
|
CheckForMemoryLeaks();
|
|
}
|
|
|
|
bool Fuzzer::RunOne(const uint8_t *Data, size_t Size) {
|
|
TotalNumberOfRuns++;
|
|
|
|
PrepareCoverageBeforeRun();
|
|
ExecuteCallback(Data, Size);
|
|
bool Res = CheckCoverageAfterRun();
|
|
|
|
auto UnitStopTime = system_clock::now();
|
|
auto TimeOfUnit =
|
|
duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
|
|
if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
|
|
secondsSinceProcessStartUp() >= 2)
|
|
PrintStats("pulse ");
|
|
if (TimeOfUnit > TimeOfLongestUnitInSeconds &&
|
|
TimeOfUnit >= Options.ReportSlowUnits) {
|
|
TimeOfLongestUnitInSeconds = TimeOfUnit;
|
|
Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
|
|
WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
|
|
}
|
|
return Res;
|
|
}
|
|
|
|
void Fuzzer::RunOneAndUpdateCorpus(uint8_t *Data, size_t Size) {
|
|
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
|
|
return;
|
|
if (Options.OnlyASCII)
|
|
ToASCII(Data, Size);
|
|
if (RunOne(Data, Size))
|
|
ReportNewCoverage({Data, Data + Size});
|
|
}
|
|
|
|
// 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() {
|
|
Mallocs = 0;
|
|
Frees = 0;
|
|
}
|
|
// Returns true if there were more mallocs than frees.
|
|
bool Stop() { return Mallocs > Frees; }
|
|
size_t Mallocs;
|
|
size_t Frees;
|
|
};
|
|
|
|
static thread_local MallocFreeTracer AllocTracer;
|
|
|
|
extern "C" {
|
|
void __sanitizer_malloc_hook(void *ptr, size_t size) { AllocTracer.Mallocs++; }
|
|
void __sanitizer_free_hook(void *ptr) { AllocTracer.Frees++; }
|
|
} // extern "C"
|
|
|
|
void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
|
|
UnitStartTime = system_clock::now();
|
|
// We copy the contents of Unit into a separate heap buffer
|
|
// so that we reliably find buffer overflows in it.
|
|
std::unique_ptr<uint8_t[]> DataCopy(new uint8_t[Size]);
|
|
memcpy(DataCopy.get(), Data, Size);
|
|
AssignTaintLabels(DataCopy.get(), Size);
|
|
CurrentUnitData = DataCopy.get();
|
|
CurrentUnitSize = Size;
|
|
AllocTracer.Start();
|
|
int Res = CB(DataCopy.get(), Size);
|
|
(void)Res;
|
|
HasMoreMallocsThanFrees = AllocTracer.Stop();
|
|
CurrentUnitSize = 0;
|
|
CurrentUnitData = nullptr;
|
|
assert(Res == 0);
|
|
}
|
|
|
|
size_t Fuzzer::RecordBlockCoverage() {
|
|
CHECK_WEAK_API_FUNCTION(__sanitizer_get_total_unique_coverage);
|
|
uintptr_t PrevCoverage = LastRecordedBlockCoverage;
|
|
LastRecordedBlockCoverage = __sanitizer_get_total_unique_coverage();
|
|
|
|
if (PrevCoverage == LastRecordedBlockCoverage || !Options.PrintNewCovPcs)
|
|
return LastRecordedBlockCoverage;
|
|
|
|
uintptr_t PrevBufferLen = LastCoveragePcBufferLen;
|
|
uintptr_t *CoverageBuf;
|
|
LastCoveragePcBufferLen = __sanitizer_get_coverage_pc_buffer(&CoverageBuf);
|
|
assert(CoverageBuf);
|
|
for (size_t i = PrevBufferLen; i < LastCoveragePcBufferLen; ++i) {
|
|
Printf("%p\n", CoverageBuf[i]);
|
|
}
|
|
|
|
return LastRecordedBlockCoverage;
|
|
}
|
|
|
|
size_t Fuzzer::RecordCallerCalleeCoverage() {
|
|
if (!Options.UseIndirCalls)
|
|
return 0;
|
|
if (!__sanitizer_get_total_unique_caller_callee_pairs)
|
|
return 0;
|
|
return LastRecordedCallerCalleeCoverage =
|
|
__sanitizer_get_total_unique_caller_callee_pairs();
|
|
}
|
|
|
|
void Fuzzer::PrepareCoverageBeforeRun() {
|
|
if (Options.UseCounters) {
|
|
size_t NumCounters = __sanitizer_get_number_of_counters();
|
|
CounterBitmap.resize(NumCounters);
|
|
__sanitizer_update_counter_bitset_and_clear_counters(0);
|
|
}
|
|
RecordBlockCoverage();
|
|
RecordCallerCalleeCoverage();
|
|
}
|
|
|
|
bool Fuzzer::CheckCoverageAfterRun() {
|
|
size_t OldCoverage = LastRecordedBlockCoverage;
|
|
size_t NewCoverage = RecordBlockCoverage();
|
|
size_t OldCallerCalleeCoverage = LastRecordedCallerCalleeCoverage;
|
|
size_t NewCallerCalleeCoverage = RecordCallerCalleeCoverage();
|
|
size_t NumNewBits = 0;
|
|
size_t OldPcMapSize = LastRecordedPcMapSize;
|
|
PcMapMergeCurrentToCombined();
|
|
size_t NewPcMapSize = PcMapCombinedSize();
|
|
LastRecordedPcMapSize = NewPcMapSize;
|
|
if (NewPcMapSize > OldPcMapSize)
|
|
return true;
|
|
if (Options.UseCounters)
|
|
NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
|
|
CounterBitmap.data());
|
|
return NewCoverage > OldCoverage ||
|
|
NewCallerCalleeCoverage > OldCallerCalleeCoverage || NumNewBits;
|
|
}
|
|
|
|
void Fuzzer::WriteToOutputCorpus(const Unit &U) {
|
|
if (Options.OutputCorpus.empty())
|
|
return;
|
|
std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
|
|
WriteToFile(U, Path);
|
|
if (Options.Verbosity >= 2)
|
|
Printf("Written to %s\n", Path.c_str());
|
|
assert(!Options.OnlyASCII || IsASCII(U));
|
|
}
|
|
|
|
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::SaveCorpus() {
|
|
if (Options.OutputCorpus.empty())
|
|
return;
|
|
for (const auto &U : Corpus)
|
|
WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
|
|
if (Options.Verbosity)
|
|
Printf("Written corpus of %zd files to %s\n", Corpus.size(),
|
|
Options.OutputCorpus.c_str());
|
|
}
|
|
|
|
void Fuzzer::PrintStatusForNewUnit(const Unit &U) {
|
|
if (!Options.PrintNEW)
|
|
return;
|
|
PrintStats("NEW ", "");
|
|
if (Options.Verbosity) {
|
|
Printf(" L: %zd ", U.size());
|
|
MD.PrintMutationSequence();
|
|
Printf("\n");
|
|
}
|
|
}
|
|
|
|
void Fuzzer::ReportNewCoverage(const Unit &U) {
|
|
Corpus.push_back(U);
|
|
UpdateCorpusDistribution();
|
|
UnitHashesAddedToCorpus.insert(Hash(U));
|
|
MD.RecordSuccessfulMutationSequence();
|
|
PrintStatusForNewUnit(U);
|
|
WriteToOutputCorpus(U);
|
|
NumberOfNewUnitsAdded++;
|
|
}
|
|
|
|
// Finds minimal number of units in 'Extra' that add coverage to 'Initial'.
|
|
// We do it by actually executing the units, sometimes more than once,
|
|
// because we may be using different coverage-like signals and the only
|
|
// common thing between them is that we can say "this unit found new stuff".
|
|
UnitVector Fuzzer::FindExtraUnits(const UnitVector &Initial,
|
|
const UnitVector &Extra) {
|
|
UnitVector Res = Extra;
|
|
size_t OldSize = Res.size();
|
|
for (int Iter = 0; Iter < 10; Iter++) {
|
|
ShuffleCorpus(&Res);
|
|
ResetCoverage();
|
|
|
|
for (auto &U : Initial)
|
|
RunOne(U);
|
|
|
|
Corpus.clear();
|
|
for (auto &U : Res)
|
|
if (RunOne(U))
|
|
Corpus.push_back(U);
|
|
|
|
char Stat[7] = "MIN ";
|
|
Stat[3] = '0' + Iter;
|
|
PrintStats(Stat);
|
|
|
|
size_t NewSize = Corpus.size();
|
|
Res.swap(Corpus);
|
|
|
|
if (NewSize == OldSize)
|
|
break;
|
|
OldSize = NewSize;
|
|
}
|
|
return Res;
|
|
}
|
|
|
|
void Fuzzer::Merge(const std::vector<std::string> &Corpora) {
|
|
if (Corpora.size() <= 1) {
|
|
Printf("Merge requires two or more corpus dirs\n");
|
|
return;
|
|
}
|
|
std::vector<std::string> ExtraCorpora(Corpora.begin() + 1, Corpora.end());
|
|
|
|
assert(Options.MaxLen > 0);
|
|
UnitVector Initial, Extra;
|
|
ReadDirToVectorOfUnits(Corpora[0].c_str(), &Initial, nullptr, Options.MaxLen);
|
|
for (auto &C : ExtraCorpora)
|
|
ReadDirToVectorOfUnits(C.c_str(), &Extra, nullptr, Options.MaxLen);
|
|
|
|
if (!Initial.empty()) {
|
|
Printf("=== Minimizing the initial corpus of %zd units\n", Initial.size());
|
|
Initial = FindExtraUnits({}, Initial);
|
|
}
|
|
|
|
Printf("=== Merging extra %zd units\n", Extra.size());
|
|
auto Res = FindExtraUnits(Initial, Extra);
|
|
|
|
for (auto &U: Res)
|
|
WriteToOutputCorpus(U);
|
|
|
|
Printf("=== Merge: written %zd units\n", Res.size());
|
|
}
|
|
|
|
// Tries to call lsan, and if there are leaks exits. We call this right after
|
|
// the initial corpus was read because if there are leaky inputs in the corpus
|
|
// further fuzzing will likely hit OOMs.
|
|
void Fuzzer::CheckForMemoryLeaks() {
|
|
if (!Options.DetectLeaks) return;
|
|
if (!__lsan_do_recoverable_leak_check)
|
|
return;
|
|
if (__lsan_do_recoverable_leak_check()) {
|
|
Printf("==%d== ERROR: libFuzzer: initial corpus triggers memory leaks.\n"
|
|
"Exiting now. Use -detect_leaks=0 to disable leak detection here.\n"
|
|
"LeakSanitizer will still check for leaks at the process exit.\n",
|
|
GetPid());
|
|
PrintFinalStats();
|
|
_Exit(Options.ErrorExitCode);
|
|
}
|
|
}
|
|
|
|
// Tries detecting a memory leak on the particular input that we have just
|
|
// executed before calling this function.
|
|
void Fuzzer::TryDetectingAMemoryLeak(uint8_t *Data, size_t Size) {
|
|
if (!HasMoreMallocsThanFrees) return; // mallocs==frees, a leak is unlikely.
|
|
if (!Options.DetectLeaks) return;
|
|
if (!&__lsan_enable || !&__lsan_disable || !__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.
|
|
__lsan_disable();
|
|
RunOneAndUpdateCorpus(Data, Size);
|
|
__lsan_enable();
|
|
if (!HasMoreMallocsThanFrees) return; // a leak is unlikely.
|
|
// Now perform the actual lsan pass. This is expensive and we must ensure
|
|
// we don't call it too often.
|
|
if (__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
|
|
CurrentUnitData = Data;
|
|
CurrentUnitSize = Size;
|
|
DumpCurrentUnit("leak-");
|
|
PrintFinalStats();
|
|
_Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
|
|
}
|
|
}
|
|
|
|
void Fuzzer::MutateAndTestOne() {
|
|
MD.StartMutationSequence();
|
|
|
|
auto &U = ChooseUnitToMutate();
|
|
MutateInPlaceHere.resize(Options.MaxLen);
|
|
size_t Size = U.size();
|
|
assert(Size <= Options.MaxLen && "Oversized Unit");
|
|
memcpy(MutateInPlaceHere.data(), U.data(), Size);
|
|
|
|
for (int i = 0; i < Options.MutateDepth; i++) {
|
|
size_t NewSize = 0;
|
|
if (LLVMFuzzerCustomMutator)
|
|
NewSize = LLVMFuzzerCustomMutator(MutateInPlaceHere.data(), Size,
|
|
Options.MaxLen, MD.GetRand().Rand());
|
|
else
|
|
NewSize = MD.Mutate(MutateInPlaceHere.data(), Size, Options.MaxLen);
|
|
assert(NewSize > 0 && "Mutator returned empty unit");
|
|
assert(NewSize <= Options.MaxLen &&
|
|
"Mutator return overisized unit");
|
|
Size = NewSize;
|
|
if (i == 0)
|
|
StartTraceRecording();
|
|
RunOneAndUpdateCorpus(MutateInPlaceHere.data(), Size);
|
|
StopTraceRecording();
|
|
TryDetectingAMemoryLeak(MutateInPlaceHere.data(), Size);
|
|
}
|
|
}
|
|
|
|
// Returns an index of random unit from the corpus to mutate.
|
|
// Hypothesis: units added to the corpus last are more likely to be interesting.
|
|
// This function gives more weight to the more recent units.
|
|
size_t Fuzzer::ChooseUnitIdxToMutate() {
|
|
size_t Idx =
|
|
static_cast<size_t>(CorpusDistribution(MD.GetRand().Get_mt19937()));
|
|
assert(Idx < Corpus.size());
|
|
return Idx;
|
|
}
|
|
|
|
void Fuzzer::ResetCoverage() {
|
|
CHECK_WEAK_API_FUNCTION(__sanitizer_reset_coverage);
|
|
__sanitizer_reset_coverage();
|
|
CounterBitmap.clear();
|
|
}
|
|
|
|
// Experimental search heuristic: drilling.
|
|
// - Read, shuffle, execute and minimize the corpus.
|
|
// - Choose one random unit.
|
|
// - Reset the coverage.
|
|
// - Start fuzzing as if the chosen unit was the only element of the corpus.
|
|
// - When done, reset the coverage again.
|
|
// - Merge the newly created corpus into the original one.
|
|
void Fuzzer::Drill() {
|
|
// The corpus is already read, shuffled, and minimized.
|
|
assert(!Corpus.empty());
|
|
Options.PrintNEW = false; // Don't print NEW status lines when drilling.
|
|
|
|
Unit U = ChooseUnitToMutate();
|
|
|
|
ResetCoverage();
|
|
|
|
std::vector<Unit> SavedCorpus;
|
|
SavedCorpus.swap(Corpus);
|
|
Corpus.push_back(U);
|
|
UpdateCorpusDistribution();
|
|
assert(Corpus.size() == 1);
|
|
RunOne(U);
|
|
PrintStats("DRILL ");
|
|
std::string SavedOutputCorpusPath; // Don't write new units while drilling.
|
|
SavedOutputCorpusPath.swap(Options.OutputCorpus);
|
|
Loop();
|
|
|
|
ResetCoverage();
|
|
|
|
PrintStats("REINIT");
|
|
SavedOutputCorpusPath.swap(Options.OutputCorpus);
|
|
for (auto &U : SavedCorpus)
|
|
RunOne(U);
|
|
PrintStats("MERGE ");
|
|
Options.PrintNEW = true;
|
|
size_t NumMerged = 0;
|
|
for (auto &U : Corpus) {
|
|
if (RunOne(U)) {
|
|
PrintStatusForNewUnit(U);
|
|
NumMerged++;
|
|
WriteToOutputCorpus(U);
|
|
}
|
|
}
|
|
PrintStats("MERGED");
|
|
if (NumMerged && Options.Verbosity)
|
|
Printf("Drilling discovered %zd new units\n", NumMerged);
|
|
}
|
|
|
|
void Fuzzer::Loop() {
|
|
system_clock::time_point LastCorpusReload = system_clock::now();
|
|
if (Options.DoCrossOver)
|
|
MD.SetCorpus(&Corpus);
|
|
while (true) {
|
|
auto Now = system_clock::now();
|
|
if (duration_cast<seconds>(Now - LastCorpusReload).count()) {
|
|
RereadOutputCorpus(Options.MaxLen);
|
|
LastCorpusReload = Now;
|
|
}
|
|
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
|
|
break;
|
|
if (Options.MaxTotalTimeSec > 0 &&
|
|
secondsSinceProcessStartUp() >
|
|
static_cast<size_t>(Options.MaxTotalTimeSec))
|
|
break;
|
|
// Perform several mutations and runs.
|
|
MutateAndTestOne();
|
|
}
|
|
|
|
PrintStats("DONE ", "\n");
|
|
MD.PrintRecommendedDictionary();
|
|
}
|
|
|
|
void Fuzzer::UpdateCorpusDistribution() {
|
|
size_t N = Corpus.size();
|
|
std::vector<double> Intervals(N + 1);
|
|
std::vector<double> Weights(N);
|
|
std::iota(Intervals.begin(), Intervals.end(), 0);
|
|
std::iota(Weights.begin(), Weights.end(), 1);
|
|
CorpusDistribution = std::piecewise_constant_distribution<double>(
|
|
Intervals.begin(), Intervals.end(), Weights.begin());
|
|
}
|
|
|
|
} // namespace fuzzer
|