forked from mirrors/gecko-dev
419 lines
14 KiB
C++
419 lines
14 KiB
C++
//===- FuzzerMerge.cpp - merging corpora ----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Merging corpora.
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//===----------------------------------------------------------------------===//
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#include "FuzzerCommand.h"
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#include "FuzzerMerge.h"
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#include "FuzzerIO.h"
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#include "FuzzerInternal.h"
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#include "FuzzerTracePC.h"
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#include "FuzzerUtil.h"
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#include <fstream>
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#include <iterator>
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#include <set>
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#include <sstream>
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#include <unordered_set>
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namespace fuzzer {
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bool Merger::Parse(const std::string &Str, bool ParseCoverage) {
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std::istringstream SS(Str);
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return Parse(SS, ParseCoverage);
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}
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int Merger::ParseOrExit(std::istream &IS, bool ParseCoverage) {
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if (!Parse(IS, ParseCoverage)) {
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Printf("MERGE: failed to parse the control file (unexpected error)\n");
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return 1;
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}
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return 0;
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}
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// The control file example:
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//
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// 3 # The number of inputs
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// 1 # The number of inputs in the first corpus, <= the previous number
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// file0
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// file1
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// file2 # One file name per line.
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// STARTED 0 123 # FileID, file size
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// FT 0 1 4 6 8 # FileID COV1 COV2 ...
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// COV 0 7 8 9 # FileID COV1 COV1
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// STARTED 1 456 # If FT is missing, the input crashed while processing.
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// STARTED 2 567
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// FT 2 8 9
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// COV 2 11 12
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bool Merger::Parse(std::istream &IS, bool ParseCoverage) {
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LastFailure.clear();
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std::string Line;
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// Parse NumFiles.
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if (!std::getline(IS, Line, '\n')) return false;
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std::istringstream L1(Line);
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size_t NumFiles = 0;
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L1 >> NumFiles;
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if (NumFiles == 0 || NumFiles > 10000000) return false;
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// Parse NumFilesInFirstCorpus.
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if (!std::getline(IS, Line, '\n')) return false;
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std::istringstream L2(Line);
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NumFilesInFirstCorpus = NumFiles + 1;
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L2 >> NumFilesInFirstCorpus;
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if (NumFilesInFirstCorpus > NumFiles) return false;
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// Parse file names.
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Files.resize(NumFiles);
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for (size_t i = 0; i < NumFiles; i++)
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if (!std::getline(IS, Files[i].Name, '\n'))
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return false;
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// Parse STARTED, FT, and COV lines.
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size_t ExpectedStartMarker = 0;
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const size_t kInvalidStartMarker = -1;
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size_t LastSeenStartMarker = kInvalidStartMarker;
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Vector<uint32_t> TmpFeatures;
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Set<uint32_t> PCs;
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while (std::getline(IS, Line, '\n')) {
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std::istringstream ISS1(Line);
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std::string Marker;
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size_t N;
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ISS1 >> Marker;
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ISS1 >> N;
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if (Marker == "STARTED") {
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// STARTED FILE_ID FILE_SIZE
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if (ExpectedStartMarker != N)
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return false;
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ISS1 >> Files[ExpectedStartMarker].Size;
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LastSeenStartMarker = ExpectedStartMarker;
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assert(ExpectedStartMarker < Files.size());
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ExpectedStartMarker++;
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} else if (Marker == "FT") {
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// FT FILE_ID COV1 COV2 COV3 ...
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size_t CurrentFileIdx = N;
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if (CurrentFileIdx != LastSeenStartMarker)
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return false;
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LastSeenStartMarker = kInvalidStartMarker;
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if (ParseCoverage) {
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TmpFeatures.clear(); // use a vector from outer scope to avoid resizes.
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while (ISS1 >> N)
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TmpFeatures.push_back(N);
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std::sort(TmpFeatures.begin(), TmpFeatures.end());
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Files[CurrentFileIdx].Features = TmpFeatures;
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}
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} else if (Marker == "COV") {
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size_t CurrentFileIdx = N;
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if (ParseCoverage)
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while (ISS1 >> N)
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if (PCs.insert(N).second)
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Files[CurrentFileIdx].Cov.push_back(N);
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} else {
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return false;
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}
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}
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if (LastSeenStartMarker != kInvalidStartMarker)
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LastFailure = Files[LastSeenStartMarker].Name;
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FirstNotProcessedFile = ExpectedStartMarker;
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return true;
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}
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size_t Merger::ApproximateMemoryConsumption() const {
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size_t Res = 0;
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for (const auto &F: Files)
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Res += sizeof(F) + F.Features.size() * sizeof(F.Features[0]);
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return Res;
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}
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// Decides which files need to be merged (add those to NewFiles).
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// Returns the number of new features added.
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size_t Merger::Merge(const Set<uint32_t> &InitialFeatures,
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Set<uint32_t> *NewFeatures,
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const Set<uint32_t> &InitialCov, Set<uint32_t> *NewCov,
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Vector<std::string> *NewFiles) {
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NewFiles->clear();
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assert(NumFilesInFirstCorpus <= Files.size());
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Set<uint32_t> AllFeatures = InitialFeatures;
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// What features are in the initial corpus?
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for (size_t i = 0; i < NumFilesInFirstCorpus; i++) {
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auto &Cur = Files[i].Features;
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AllFeatures.insert(Cur.begin(), Cur.end());
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}
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// Remove all features that we already know from all other inputs.
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for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
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auto &Cur = Files[i].Features;
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Vector<uint32_t> Tmp;
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std::set_difference(Cur.begin(), Cur.end(), AllFeatures.begin(),
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AllFeatures.end(), std::inserter(Tmp, Tmp.begin()));
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Cur.swap(Tmp);
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}
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// Sort. Give preference to
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// * smaller files
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// * files with more features.
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std::sort(Files.begin() + NumFilesInFirstCorpus, Files.end(),
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[&](const MergeFileInfo &a, const MergeFileInfo &b) -> bool {
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if (a.Size != b.Size)
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return a.Size < b.Size;
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return a.Features.size() > b.Features.size();
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});
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// One greedy pass: add the file's features to AllFeatures.
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// If new features were added, add this file to NewFiles.
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for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
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auto &Cur = Files[i].Features;
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// Printf("%s -> sz %zd ft %zd\n", Files[i].Name.c_str(),
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// Files[i].Size, Cur.size());
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bool FoundNewFeatures = false;
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for (auto Fe: Cur) {
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if (AllFeatures.insert(Fe).second) {
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FoundNewFeatures = true;
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NewFeatures->insert(Fe);
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}
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}
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if (FoundNewFeatures)
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NewFiles->push_back(Files[i].Name);
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for (auto Cov : Files[i].Cov)
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if (InitialCov.find(Cov) == InitialCov.end())
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NewCov->insert(Cov);
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}
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return NewFeatures->size();
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}
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Set<uint32_t> Merger::AllFeatures() const {
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Set<uint32_t> S;
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for (auto &File : Files)
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S.insert(File.Features.begin(), File.Features.end());
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return S;
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}
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// Inner process. May crash if the target crashes.
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int Fuzzer::CrashResistantMergeInternalStep(const std::string &CFPath) {
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Printf("MERGE-INNER: using the control file '%s'\n", CFPath.c_str());
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Merger M;
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std::ifstream IF(CFPath);
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int Res = M.ParseOrExit(IF, false);
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if (Res != 0)
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return Res;
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IF.close();
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if (!M.LastFailure.empty())
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Printf("MERGE-INNER: '%s' caused a failure at the previous merge step\n",
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M.LastFailure.c_str());
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Printf("MERGE-INNER: %zd total files;"
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" %zd processed earlier; will process %zd files now\n",
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M.Files.size(), M.FirstNotProcessedFile,
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M.Files.size() - M.FirstNotProcessedFile);
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std::ofstream OF(CFPath, std::ofstream::out | std::ofstream::app);
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Set<size_t> AllFeatures;
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auto PrintStatsWrapper = [this, &AllFeatures](const char* Where) {
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this->PrintStats(Where, "\n", 0, AllFeatures.size());
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};
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Set<const TracePC::PCTableEntry *> AllPCs;
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for (size_t i = M.FirstNotProcessedFile; i < M.Files.size(); i++) {
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if (Fuzzer::MaybeExitGracefully())
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return 0;
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auto U = FileToVector(M.Files[i].Name);
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if (U.size() > MaxInputLen) {
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U.resize(MaxInputLen);
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U.shrink_to_fit();
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}
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// Write the pre-run marker.
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OF << "STARTED " << i << " " << U.size() << "\n";
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OF.flush(); // Flush is important since Command::Execute may crash.
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// Run.
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TPC.ResetMaps();
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if (ExecuteCallback(U.data(), U.size()) > 0) {
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continue;
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}
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// Collect coverage. We are iterating over the files in this order:
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// * First, files in the initial corpus ordered by size, smallest first.
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// * Then, all other files, smallest first.
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// So it makes no sense to record all features for all files, instead we
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// only record features that were not seen before.
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Set<size_t> UniqFeatures;
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TPC.CollectFeatures([&](size_t Feature) {
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if (AllFeatures.insert(Feature).second)
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UniqFeatures.insert(Feature);
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});
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TPC.UpdateObservedPCs();
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// Show stats.
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if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)))
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PrintStatsWrapper("pulse ");
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if (TotalNumberOfRuns == M.NumFilesInFirstCorpus)
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PrintStatsWrapper("LOADED");
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// Write the post-run marker and the coverage.
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OF << "FT " << i;
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for (size_t F : UniqFeatures)
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OF << " " << F;
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OF << "\n";
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OF << "COV " << i;
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TPC.ForEachObservedPC([&](const TracePC::PCTableEntry *TE) {
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if (AllPCs.insert(TE).second)
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OF << " " << TPC.PCTableEntryIdx(TE);
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});
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OF << "\n";
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OF.flush();
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}
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PrintStatsWrapper("DONE ");
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return 0;
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}
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static int WriteNewControlFile(const std::string &CFPath,
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const Vector<SizedFile> &OldCorpus,
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const Vector<SizedFile> &NewCorpus,
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const Vector<MergeFileInfo> &KnownFiles,
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size_t &NumFiles) {
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std::unordered_set<std::string> FilesToSkip;
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for (auto &SF: KnownFiles)
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FilesToSkip.insert(SF.Name);
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Vector<std::string> FilesToUse;
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auto MaybeUseFile = [=, &FilesToUse](std::string Name) {
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if (FilesToSkip.find(Name) == FilesToSkip.end())
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FilesToUse.push_back(Name);
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};
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for (auto &SF: OldCorpus)
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MaybeUseFile(SF.File);
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auto FilesToUseFromOldCorpus = FilesToUse.size();
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for (auto &SF: NewCorpus)
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MaybeUseFile(SF.File);
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RemoveFile(CFPath);
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std::ofstream ControlFile(CFPath);
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ControlFile << FilesToUse.size() << "\n";
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ControlFile << FilesToUseFromOldCorpus << "\n";
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for (auto &FN: FilesToUse)
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ControlFile << FN << "\n";
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if (!ControlFile) {
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Printf("MERGE-OUTER: failed to write to the control file: %s\n",
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CFPath.c_str());
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return 1;
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}
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NumFiles = FilesToUse.size();
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return 0;
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}
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// Outer process. Does not call the target code and thus should not fail.
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int CrashResistantMerge(const Vector<std::string> &Args,
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const Vector<SizedFile> &OldCorpus,
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const Vector<SizedFile> &NewCorpus,
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Vector<std::string> *NewFiles,
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const Set<uint32_t> &InitialFeatures,
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Set<uint32_t> *NewFeatures,
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const Set<uint32_t> &InitialCov,
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Set<uint32_t> *NewCov,
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const std::string &CFPath,
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bool V /*Verbose*/) {
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if (NewCorpus.empty() && OldCorpus.empty()) return 0; // Nothing to merge.
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size_t NumAttempts = 0;
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int Res;
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Vector<MergeFileInfo> KnownFiles;
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if (FileSize(CFPath)) {
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VPrintf(V, "MERGE-OUTER: non-empty control file provided: '%s'\n",
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CFPath.c_str());
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Merger M;
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std::ifstream IF(CFPath);
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if (M.Parse(IF, /*ParseCoverage=*/true)) {
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VPrintf(V, "MERGE-OUTER: control file ok, %zd files total,"
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" first not processed file %zd\n",
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M.Files.size(), M.FirstNotProcessedFile);
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if (!M.LastFailure.empty())
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VPrintf(V, "MERGE-OUTER: '%s' will be skipped as unlucky "
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"(merge has stumbled on it the last time)\n",
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M.LastFailure.c_str());
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if (M.FirstNotProcessedFile >= M.Files.size()) {
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// Merge has already been completed with the given merge control file.
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if (M.Files.size() == OldCorpus.size() + NewCorpus.size()) {
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VPrintf(
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V,
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"MERGE-OUTER: nothing to do, merge has been completed before\n");
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Fuzzer::GracefullyExit();
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return 0;
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}
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// Number of input files likely changed, start merge from scratch, but
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// reuse coverage information from the given merge control file.
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VPrintf(
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V,
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"MERGE-OUTER: starting merge from scratch, but reusing coverage "
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"information from the given control file\n");
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KnownFiles = M.Files;
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} else {
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// There is a merge in progress, continue.
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NumAttempts = M.Files.size() - M.FirstNotProcessedFile;
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}
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} else {
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VPrintf(V, "MERGE-OUTER: bad control file, will overwrite it\n");
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}
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}
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if (!NumAttempts) {
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// The supplied control file is empty or bad, create a fresh one.
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VPrintf(V, "MERGE-OUTER: "
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"%zd files, %zd in the initial corpus, %zd processed earlier\n",
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OldCorpus.size() + NewCorpus.size(), OldCorpus.size(),
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KnownFiles.size());
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Res = WriteNewControlFile(CFPath, OldCorpus, NewCorpus, KnownFiles, NumAttempts);
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if (Res != 0)
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return Res;
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}
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// Execute the inner process until it passes.
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// Every inner process should execute at least one input.
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Command BaseCmd(Args);
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BaseCmd.removeFlag("merge");
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BaseCmd.removeFlag("fork");
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BaseCmd.removeFlag("collect_data_flow");
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for (size_t Attempt = 1; Attempt <= NumAttempts; Attempt++) {
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if (Fuzzer::MaybeExitGracefully())
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return 0;
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VPrintf(V, "MERGE-OUTER: attempt %zd\n", Attempt);
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Command Cmd(BaseCmd);
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Cmd.addFlag("merge_control_file", CFPath);
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Cmd.addFlag("merge_inner", "1");
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if (!V) {
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Cmd.setOutputFile(getDevNull());
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Cmd.combineOutAndErr();
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}
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auto ExitCode = ExecuteCommand(Cmd);
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if (!ExitCode) {
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VPrintf(V, "MERGE-OUTER: succesfull in %zd attempt(s)\n", Attempt);
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break;
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}
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}
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// Read the control file and do the merge.
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Merger M;
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std::ifstream IF(CFPath);
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IF.seekg(0, IF.end);
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VPrintf(V, "MERGE-OUTER: the control file has %zd bytes\n",
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(size_t)IF.tellg());
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IF.seekg(0, IF.beg);
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Res = M.ParseOrExit(IF, true);
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if (Res != 0)
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return Res;
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IF.close();
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VPrintf(V,
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"MERGE-OUTER: consumed %zdMb (%zdMb rss) to parse the control file\n",
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M.ApproximateMemoryConsumption() >> 20, GetPeakRSSMb());
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M.Files.insert(M.Files.end(), KnownFiles.begin(), KnownFiles.end());
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M.Merge(InitialFeatures, NewFeatures, InitialCov, NewCov, NewFiles);
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VPrintf(V, "MERGE-OUTER: %zd new files with %zd new features added; "
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"%zd new coverage edges\n",
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NewFiles->size(), NewFeatures->size(), NewCov->size());
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return 0;
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}
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} // namespace fuzzer
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