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llvm-project/compiler-rt/lib/fuzzer/FuzzerMerge.cpp

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//===- FuzzerMerge.cpp - merging corpora ----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Merging corpora.
//===----------------------------------------------------------------------===//
#include "FuzzerMerge.h"
#include "FuzzerIO.h"
#include "FuzzerInternal.h"
#include "FuzzerTracePC.h"
#include "FuzzerUtil.h"
#include <fstream>
#include <iterator>
#include <set>
#include <sstream>
namespace fuzzer {
bool Merger::Parse(const std::string &Str, bool ParseCoverage) {
std::istringstream SS(Str);
return Parse(SS, ParseCoverage);
}
void Merger::ParseOrExit(std::istream &IS, bool ParseCoverage) {
if (!Parse(IS, ParseCoverage)) {
Printf("MERGE: failed to parse the control file (unexpected error)\n");
exit(1);
}
}
// The control file example:
//
// 3 # The number of inputs
// 1 # The number of inputs in the first corpus, <= the previous number
// file0
// file1
// file2 # One file name per line.
// STARTED 0 123 # FileID, file size
// DONE 0 1 4 6 8 # FileID COV1 COV2 ...
// STARTED 1 456 # If DONE is missing, the input crashed while processing.
// STARTED 2 567
// DONE 2 8 9
bool Merger::Parse(std::istream &IS, bool ParseCoverage) {
LastFailure.clear();
std::string Line;
// Parse NumFiles.
if (!std::getline(IS, Line, '\n')) return false;
std::istringstream L1(Line);
size_t NumFiles = 0;
L1 >> NumFiles;
if (NumFiles == 0 || NumFiles > 10000000) return false;
// Parse NumFilesInFirstCorpus.
if (!std::getline(IS, Line, '\n')) return false;
std::istringstream L2(Line);
NumFilesInFirstCorpus = NumFiles + 1;
L2 >> NumFilesInFirstCorpus;
if (NumFilesInFirstCorpus > NumFiles) return false;
// Parse file names.
Files.resize(NumFiles);
for (size_t i = 0; i < NumFiles; i++)
if (!std::getline(IS, Files[i].Name, '\n'))
return false;
// Parse STARTED and DONE lines.
size_t ExpectedStartMarker = 0;
const size_t kInvalidStartMarker = -1;
size_t LastSeenStartMarker = kInvalidStartMarker;
Vector<uint32_t> TmpFeatures;
while (std::getline(IS, Line, '\n')) {
std::istringstream ISS1(Line);
std::string Marker;
size_t N;
ISS1 >> Marker;
ISS1 >> N;
if (Marker == "STARTED") {
// STARTED FILE_ID FILE_SIZE
if (ExpectedStartMarker != N)
return false;
ISS1 >> Files[ExpectedStartMarker].Size;
LastSeenStartMarker = ExpectedStartMarker;
assert(ExpectedStartMarker < Files.size());
ExpectedStartMarker++;
} else if (Marker == "DONE") {
// DONE FILE_ID COV1 COV2 COV3 ...
size_t CurrentFileIdx = N;
if (CurrentFileIdx != LastSeenStartMarker)
return false;
LastSeenStartMarker = kInvalidStartMarker;
if (ParseCoverage) {
TmpFeatures.clear(); // use a vector from outer scope to avoid resizes.
while (ISS1 >> std::hex >> N)
TmpFeatures.push_back(N);
std::sort(TmpFeatures.begin(), TmpFeatures.end());
Files[CurrentFileIdx].Features = TmpFeatures;
}
} else {
return false;
}
}
if (LastSeenStartMarker != kInvalidStartMarker)
LastFailure = Files[LastSeenStartMarker].Name;
FirstNotProcessedFile = ExpectedStartMarker;
return true;
}
size_t Merger::ApproximateMemoryConsumption() const {
size_t Res = 0;
for (const auto &F: Files)
Res += sizeof(F) + F.Features.size() * sizeof(F.Features[0]);
return Res;
}
// Decides which files need to be merged (add thost to NewFiles).
// Returns the number of new features added.
size_t Merger::Merge(const Set<uint32_t> &InitialFeatures,
Vector<std::string> *NewFiles) {
NewFiles->clear();
assert(NumFilesInFirstCorpus <= Files.size());
Set<uint32_t> AllFeatures(InitialFeatures);
// What features are in the initial corpus?
for (size_t i = 0; i < NumFilesInFirstCorpus; i++) {
auto &Cur = Files[i].Features;
AllFeatures.insert(Cur.begin(), Cur.end());
}
size_t InitialNumFeatures = AllFeatures.size();
// Remove all features that we already know from all other inputs.
for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
auto &Cur = Files[i].Features;
Vector<uint32_t> Tmp;
std::set_difference(Cur.begin(), Cur.end(), AllFeatures.begin(),
AllFeatures.end(), std::inserter(Tmp, Tmp.begin()));
Cur.swap(Tmp);
}
// Sort. Give preference to
// * smaller files
// * files with more features.
std::sort(Files.begin() + NumFilesInFirstCorpus, Files.end(),
[&](const MergeFileInfo &a, const MergeFileInfo &b) -> bool {
if (a.Size != b.Size)
return a.Size < b.Size;
return a.Features.size() > b.Features.size();
});
// One greedy pass: add the file's features to AllFeatures.
// If new features were added, add this file to NewFiles.
for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
auto &Cur = Files[i].Features;
// Printf("%s -> sz %zd ft %zd\n", Files[i].Name.c_str(),
// Files[i].Size, Cur.size());
size_t OldSize = AllFeatures.size();
AllFeatures.insert(Cur.begin(), Cur.end());
if (AllFeatures.size() > OldSize)
NewFiles->push_back(Files[i].Name);
}
return AllFeatures.size() - InitialNumFeatures;
}
void Merger::PrintSummary(std::ostream &OS) {
for (auto &File : Files) {
OS << std::hex;
OS << File.Name << " size: " << File.Size << " features: ";
for (auto Feature : File.Features)
OS << " " << Feature;
OS << "\n";
}
}
Set<uint32_t> Merger::AllFeatures() const {
Set<uint32_t> S;
for (auto &File : Files)
S.insert(File.Features.begin(), File.Features.end());
return S;
}
Set<uint32_t> Merger::ParseSummary(std::istream &IS) {
std::string Line, Tmp;
Set<uint32_t> Res;
while (std::getline(IS, Line, '\n')) {
size_t N;
std::istringstream ISS1(Line);
ISS1 >> Tmp; // Name
ISS1 >> Tmp; // size:
assert(Tmp == "size:" && "Corrupt summary file");
ISS1 >> std::hex;
ISS1 >> N; // File Size
ISS1 >> Tmp; // features:
assert(Tmp == "features:" && "Corrupt summary file");
while (ISS1 >> std::hex >> N)
Res.insert(N);
}
return Res;
}
// Inner process. May crash if the target crashes.
void Fuzzer::CrashResistantMergeInternalStep(const std::string &CFPath) {
Printf("MERGE-INNER: using the control file '%s'\n", CFPath.c_str());
Merger M;
std::ifstream IF(CFPath);
M.ParseOrExit(IF, false);
IF.close();
if (!M.LastFailure.empty())
Printf("MERGE-INNER: '%s' caused a failure at the previous merge step\n",
M.LastFailure.c_str());
Printf("MERGE-INNER: %zd total files;"
" %zd processed earlier; will process %zd files now\n",
M.Files.size(), M.FirstNotProcessedFile,
M.Files.size() - M.FirstNotProcessedFile);
std::ofstream OF(CFPath, std::ofstream::out | std::ofstream::app);
Set<size_t> AllFeatures;
for (size_t i = M.FirstNotProcessedFile; i < M.Files.size(); i++) {
MaybeExitGracefully();
auto U = FileToVector(M.Files[i].Name);
if (U.size() > MaxInputLen) {
U.resize(MaxInputLen);
U.shrink_to_fit();
}
std::ostringstream StartedLine;
// Write the pre-run marker.
OF << "STARTED " << std::dec << i << " " << U.size() << "\n";
OF.flush(); // Flush is important since ExecuteCommand may crash.
// Run.
TPC.ResetMaps();
ExecuteCallback(U.data(), U.size());
// Collect coverage. We are iterating over the files in this order:
// * First, files in the initial corpus ordered by size, smallest first.
// * Then, all other files, smallest first.
// So it makes no sense to record all features for all files, instead we
// only record features that were not seen before.
Set<size_t> UniqFeatures;
TPC.CollectFeatures([&](size_t Feature) {
if (AllFeatures.insert(Feature).second)
UniqFeatures.insert(Feature);
});
// Show stats.
if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)))
PrintStats("pulse ");
// Write the post-run marker and the coverage.
OF << "DONE " << i;
for (size_t F : UniqFeatures)
OF << " " << std::hex << F;
OF << "\n";
OF.flush();
}
}
static void WriteNewControlFile(const std::string &CFPath,
const Vector<SizedFile> &AllFiles,
size_t NumFilesInFirstCorpus) {
RemoveFile(CFPath);
std::ofstream ControlFile(CFPath);
ControlFile << AllFiles.size() << "\n";
ControlFile << NumFilesInFirstCorpus << "\n";
for (auto &SF: AllFiles)
ControlFile << SF.File << "\n";
if (!ControlFile) {
Printf("MERGE-OUTER: failed to write to the control file: %s\n",
CFPath.c_str());
exit(1);
}
}
// Outer process. Does not call the target code and thus sohuld not fail.
void Fuzzer::CrashResistantMerge(const Vector<std::string> &Args,
const Vector<std::string> &Corpora,
const char *CoverageSummaryInputPathOrNull,
const char *CoverageSummaryOutputPathOrNull,
const char *MergeControlFilePathOrNull) {
if (Corpora.size() <= 1) {
Printf("Merge requires two or more corpus dirs\n");
return;
}
auto CFPath =
MergeControlFilePathOrNull
? MergeControlFilePathOrNull
: DirPlusFile(TmpDir(),
"libFuzzerTemp." + std::to_string(GetPid()) + ".txt");
size_t NumAttempts = 0;
if (MergeControlFilePathOrNull && FileSize(MergeControlFilePathOrNull)) {
Printf("MERGE-OUTER: non-empty control file provided: '%s'\n",
MergeControlFilePathOrNull);
Merger M;
std::ifstream IF(MergeControlFilePathOrNull);
if (M.Parse(IF, /*ParseCoverage=*/false)) {
Printf("MERGE-OUTER: control file ok, %zd files total,"
" first not processed file %zd\n",
M.Files.size(), M.FirstNotProcessedFile);
if (!M.LastFailure.empty())
Printf("MERGE-OUTER: '%s' will be skipped as unlucky "
"(merge has stumbled on it the last time)\n",
M.LastFailure.c_str());
if (M.FirstNotProcessedFile >= M.Files.size()) {
Printf("MERGE-OUTER: nothing to do, merge has been completed before\n");
exit(0);
}
NumAttempts = M.Files.size() - M.FirstNotProcessedFile;
} else {
Printf("MERGE-OUTER: bad control file, will overwrite it\n");
}
}
if (!NumAttempts) {
// The supplied control file is empty or bad, create a fresh one.
Vector<SizedFile> AllFiles;
GetSizedFilesFromDir(Corpora[0], &AllFiles);
size_t NumFilesInFirstCorpus = AllFiles.size();
std::sort(AllFiles.begin(), AllFiles.end());
for (size_t i = 1; i < Corpora.size(); i++)
GetSizedFilesFromDir(Corpora[i], &AllFiles);
std::sort(AllFiles.begin() + NumFilesInFirstCorpus, AllFiles.end());
Printf("MERGE-OUTER: %zd files, %zd in the initial corpus\n",
AllFiles.size(), NumFilesInFirstCorpus);
WriteNewControlFile(CFPath, AllFiles, NumFilesInFirstCorpus);
NumAttempts = AllFiles.size();
}
// Execute the inner process until it passes.
// Every inner process should execute at least one input.
auto BaseCmd = SplitBefore("-ignore_remaining_args=1",
CloneArgsWithoutX(Args, "merge"));
bool Success = false;
for (size_t Attempt = 1; Attempt <= NumAttempts; Attempt++) {
MaybeExitGracefully();
Printf("MERGE-OUTER: attempt %zd\n", Attempt);
auto ExitCode =
ExecuteCommand(BaseCmd.first + " -merge_control_file=" + CFPath +
" -merge_inner=1 " + BaseCmd.second);
if (!ExitCode) {
Printf("MERGE-OUTER: succesfull in %zd attempt(s)\n", Attempt);
Success = true;
break;
}
}
if (!Success) {
Printf("MERGE-OUTER: zero succesfull attempts, exiting\n");
exit(1);
}
// Read the control file and do the merge.
Merger M;
std::ifstream IF(CFPath);
IF.seekg(0, IF.end);
Printf("MERGE-OUTER: the control file has %zd bytes\n", (size_t)IF.tellg());
IF.seekg(0, IF.beg);
M.ParseOrExit(IF, true);
IF.close();
Printf("MERGE-OUTER: consumed %zdMb (%zdMb rss) to parse the control file\n",
M.ApproximateMemoryConsumption() >> 20, GetPeakRSSMb());
if (CoverageSummaryOutputPathOrNull) {
Printf("MERGE-OUTER: writing coverage summary for %zd files to %s\n",
M.Files.size(), CoverageSummaryOutputPathOrNull);
std::ofstream SummaryOut(CoverageSummaryOutputPathOrNull);
M.PrintSummary(SummaryOut);
}
Vector<std::string> NewFiles;
Set<uint32_t> InitialFeatures;
if (CoverageSummaryInputPathOrNull) {
std::ifstream SummaryIn(CoverageSummaryInputPathOrNull);
InitialFeatures = M.ParseSummary(SummaryIn);
Printf("MERGE-OUTER: coverage summary loaded from %s, %zd features found\n",
CoverageSummaryInputPathOrNull, InitialFeatures.size());
}
size_t NumNewFeatures = M.Merge(InitialFeatures, &NewFiles);
Printf("MERGE-OUTER: %zd new files with %zd new features added\n",
NewFiles.size(), NumNewFeatures);
for (auto &F: NewFiles)
WriteToOutputCorpus(FileToVector(F));
// We are done, delete the control file if it was a temporary one.
if (!MergeControlFilePathOrNull)
RemoveFile(CFPath);
}
} // namespace fuzzer
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