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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
commit0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
treea31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /tools/fuzzing/libfuzzer/FuzzerCorpus.h
parentInitial commit. (diff)
downloadfirefox-esr-upstream/115.8.0esr.tar.xz
firefox-esr-upstream/115.8.0esr.zip
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/fuzzing/libfuzzer/FuzzerCorpus.h')
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+//===- FuzzerCorpus.h - Internal header for the Fuzzer ----------*- C++ -* ===//
+//
+// 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::InputCorpus
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_CORPUS
+#define LLVM_FUZZER_CORPUS
+
+#include "FuzzerDataFlowTrace.h"
+#include "FuzzerDefs.h"
+#include "FuzzerIO.h"
+#include "FuzzerRandom.h"
+#include "FuzzerSHA1.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <numeric>
+#include <random>
+#include <unordered_set>
+
+namespace fuzzer {
+
+struct InputInfo {
+ Unit U; // The actual input data.
+ uint8_t Sha1[kSHA1NumBytes]; // Checksum.
+ // Number of features that this input has and no smaller input has.
+ size_t NumFeatures = 0;
+ size_t Tmp = 0; // Used by ValidateFeatureSet.
+ // Stats.
+ size_t NumExecutedMutations = 0;
+ size_t NumSuccessfullMutations = 0;
+ bool MayDeleteFile = false;
+ bool Reduced = false;
+ bool HasFocusFunction = false;
+ Vector<uint32_t> UniqFeatureSet;
+ Vector<uint8_t> DataFlowTraceForFocusFunction;
+ // Power schedule.
+ bool NeedsEnergyUpdate = false;
+ double Energy = 0.0;
+ size_t SumIncidence = 0;
+ Vector<std::pair<uint32_t, uint16_t>> FeatureFreqs;
+
+ // Delete feature Idx and its frequency from FeatureFreqs.
+ bool DeleteFeatureFreq(uint32_t Idx) {
+ if (FeatureFreqs.empty())
+ return false;
+
+ // Binary search over local feature frequencies sorted by index.
+ auto Lower = std::lower_bound(FeatureFreqs.begin(), FeatureFreqs.end(),
+ std::pair<uint32_t, uint16_t>(Idx, 0));
+
+ if (Lower != FeatureFreqs.end() && Lower->first == Idx) {
+ FeatureFreqs.erase(Lower);
+ return true;
+ }
+ return false;
+ }
+
+ // Assign more energy to a high-entropy seed, i.e., that reveals more
+ // information about the globally rare features in the neighborhood
+ // of the seed. Since we do not know the entropy of a seed that has
+ // never been executed we assign fresh seeds maximum entropy and
+ // let II->Energy approach the true entropy from above.
+ void UpdateEnergy(size_t GlobalNumberOfFeatures) {
+ Energy = 0.0;
+ SumIncidence = 0;
+
+ // Apply add-one smoothing to locally discovered features.
+ for (auto F : FeatureFreqs) {
+ size_t LocalIncidence = F.second + 1;
+ Energy -= LocalIncidence * logl(LocalIncidence);
+ SumIncidence += LocalIncidence;
+ }
+
+ // Apply add-one smoothing to locally undiscovered features.
+ // PreciseEnergy -= 0; // since logl(1.0) == 0)
+ SumIncidence += (GlobalNumberOfFeatures - FeatureFreqs.size());
+
+ // Add a single locally abundant feature apply add-one smoothing.
+ size_t AbdIncidence = NumExecutedMutations + 1;
+ Energy -= AbdIncidence * logl(AbdIncidence);
+ SumIncidence += AbdIncidence;
+
+ // Normalize.
+ if (SumIncidence != 0)
+ Energy = (Energy / SumIncidence) + logl(SumIncidence);
+ }
+
+ // Increment the frequency of the feature Idx.
+ void UpdateFeatureFrequency(uint32_t Idx) {
+ NeedsEnergyUpdate = true;
+
+ // The local feature frequencies is an ordered vector of pairs.
+ // If there are no local feature frequencies, push_back preserves order.
+ // Set the feature frequency for feature Idx32 to 1.
+ if (FeatureFreqs.empty()) {
+ FeatureFreqs.push_back(std::pair<uint32_t, uint16_t>(Idx, 1));
+ return;
+ }
+
+ // Binary search over local feature frequencies sorted by index.
+ auto Lower = std::lower_bound(FeatureFreqs.begin(), FeatureFreqs.end(),
+ std::pair<uint32_t, uint16_t>(Idx, 0));
+
+ // If feature Idx32 already exists, increment its frequency.
+ // Otherwise, insert a new pair right after the next lower index.
+ if (Lower != FeatureFreqs.end() && Lower->first == Idx) {
+ Lower->second++;
+ } else {
+ FeatureFreqs.insert(Lower, std::pair<uint32_t, uint16_t>(Idx, 1));
+ }
+ }
+};
+
+struct EntropicOptions {
+ bool Enabled;
+ size_t NumberOfRarestFeatures;
+ size_t FeatureFrequencyThreshold;
+};
+
+class InputCorpus {
+ static const uint32_t kFeatureSetSize = 1 << 21;
+ static const uint8_t kMaxMutationFactor = 20;
+ static const size_t kSparseEnergyUpdates = 100;
+
+ size_t NumExecutedMutations = 0;
+
+ EntropicOptions Entropic;
+
+public:
+ InputCorpus(const std::string &OutputCorpus, EntropicOptions Entropic)
+ : Entropic(Entropic), OutputCorpus(OutputCorpus) {
+ memset(InputSizesPerFeature, 0, sizeof(InputSizesPerFeature));
+ memset(SmallestElementPerFeature, 0, sizeof(SmallestElementPerFeature));
+ }
+ ~InputCorpus() {
+ for (auto II : Inputs)
+ delete II;
+ }
+ size_t size() const { return Inputs.size(); }
+ size_t SizeInBytes() const {
+ size_t Res = 0;
+ for (auto II : Inputs)
+ Res += II->U.size();
+ return Res;
+ }
+ size_t NumActiveUnits() const {
+ size_t Res = 0;
+ for (auto II : Inputs)
+ Res += !II->U.empty();
+ return Res;
+ }
+ size_t MaxInputSize() const {
+ size_t Res = 0;
+ for (auto II : Inputs)
+ Res = std::max(Res, II->U.size());
+ return Res;
+ }
+ void IncrementNumExecutedMutations() { NumExecutedMutations++; }
+
+ size_t NumInputsThatTouchFocusFunction() {
+ return std::count_if(Inputs.begin(), Inputs.end(), [](const InputInfo *II) {
+ return II->HasFocusFunction;
+ });
+ }
+
+ size_t NumInputsWithDataFlowTrace() {
+ return std::count_if(Inputs.begin(), Inputs.end(), [](const InputInfo *II) {
+ return !II->DataFlowTraceForFocusFunction.empty();
+ });
+ }
+
+ bool empty() const { return Inputs.empty(); }
+ const Unit &operator[] (size_t Idx) const { return Inputs[Idx]->U; }
+ InputInfo *AddToCorpus(const Unit &U, size_t NumFeatures, bool MayDeleteFile,
+ bool HasFocusFunction,
+ const Vector<uint32_t> &FeatureSet,
+ const DataFlowTrace &DFT, const InputInfo *BaseII) {
+ assert(!U.empty());
+ if (FeatureDebug)
+ Printf("ADD_TO_CORPUS %zd NF %zd\n", Inputs.size(), NumFeatures);
+ Inputs.push_back(new InputInfo());
+ InputInfo &II = *Inputs.back();
+ II.U = U;
+ II.NumFeatures = NumFeatures;
+ II.MayDeleteFile = MayDeleteFile;
+ II.UniqFeatureSet = FeatureSet;
+ II.HasFocusFunction = HasFocusFunction;
+ // Assign maximal energy to the new seed.
+ II.Energy = RareFeatures.empty() ? 1.0 : log(RareFeatures.size());
+ II.SumIncidence = RareFeatures.size();
+ II.NeedsEnergyUpdate = false;
+ std::sort(II.UniqFeatureSet.begin(), II.UniqFeatureSet.end());
+ ComputeSHA1(U.data(), U.size(), II.Sha1);
+ auto Sha1Str = Sha1ToString(II.Sha1);
+ Hashes.insert(Sha1Str);
+ if (HasFocusFunction)
+ if (auto V = DFT.Get(Sha1Str))
+ II.DataFlowTraceForFocusFunction = *V;
+ // This is a gross heuristic.
+ // Ideally, when we add an element to a corpus we need to know its DFT.
+ // But if we don't, we'll use the DFT of its base input.
+ if (II.DataFlowTraceForFocusFunction.empty() && BaseII)
+ II.DataFlowTraceForFocusFunction = BaseII->DataFlowTraceForFocusFunction;
+ DistributionNeedsUpdate = true;
+ PrintCorpus();
+ // ValidateFeatureSet();
+ return &II;
+ }
+
+ // Debug-only
+ void PrintUnit(const Unit &U) {
+ if (!FeatureDebug) return;
+ for (uint8_t C : U) {
+ if (C != 'F' && C != 'U' && C != 'Z')
+ C = '.';
+ Printf("%c", C);
+ }
+ }
+
+ // Debug-only
+ void PrintFeatureSet(const Vector<uint32_t> &FeatureSet) {
+ if (!FeatureDebug) return;
+ Printf("{");
+ for (uint32_t Feature: FeatureSet)
+ Printf("%u,", Feature);
+ Printf("}");
+ }
+
+ // Debug-only
+ void PrintCorpus() {
+ if (!FeatureDebug) return;
+ Printf("======= CORPUS:\n");
+ int i = 0;
+ for (auto II : Inputs) {
+ if (std::find(II->U.begin(), II->U.end(), 'F') != II->U.end()) {
+ Printf("[%2d] ", i);
+ Printf("%s sz=%zd ", Sha1ToString(II->Sha1).c_str(), II->U.size());
+ PrintUnit(II->U);
+ Printf(" ");
+ PrintFeatureSet(II->UniqFeatureSet);
+ Printf("\n");
+ }
+ i++;
+ }
+ }
+
+ void Replace(InputInfo *II, const Unit &U) {
+ assert(II->U.size() > U.size());
+ Hashes.erase(Sha1ToString(II->Sha1));
+ DeleteFile(*II);
+ ComputeSHA1(U.data(), U.size(), II->Sha1);
+ Hashes.insert(Sha1ToString(II->Sha1));
+ II->U = U;
+ II->Reduced = true;
+ DistributionNeedsUpdate = true;
+ }
+
+ bool HasUnit(const Unit &U) { return Hashes.count(Hash(U)); }
+ bool HasUnit(const std::string &H) { return Hashes.count(H); }
+ InputInfo &ChooseUnitToMutate(Random &Rand) {
+ InputInfo &II = *Inputs[ChooseUnitIdxToMutate(Rand)];
+ assert(!II.U.empty());
+ return II;
+ }
+
+ // Returns an index of random unit from the corpus to mutate.
+ size_t ChooseUnitIdxToMutate(Random &Rand) {
+ UpdateCorpusDistribution(Rand);
+ size_t Idx = static_cast<size_t>(CorpusDistribution(Rand));
+ assert(Idx < Inputs.size());
+ return Idx;
+ }
+
+ void PrintStats() {
+ for (size_t i = 0; i < Inputs.size(); i++) {
+ const auto &II = *Inputs[i];
+ Printf(" [% 3zd %s] sz: % 5zd runs: % 5zd succ: % 5zd focus: %d\n", i,
+ Sha1ToString(II.Sha1).c_str(), II.U.size(),
+ II.NumExecutedMutations, II.NumSuccessfullMutations, II.HasFocusFunction);
+ }
+ }
+
+ void PrintFeatureSet() {
+ for (size_t i = 0; i < kFeatureSetSize; i++) {
+ if(size_t Sz = GetFeature(i))
+ Printf("[%zd: id %zd sz%zd] ", i, SmallestElementPerFeature[i], Sz);
+ }
+ Printf("\n\t");
+ for (size_t i = 0; i < Inputs.size(); i++)
+ if (size_t N = Inputs[i]->NumFeatures)
+ Printf(" %zd=>%zd ", i, N);
+ Printf("\n");
+ }
+
+ void DeleteFile(const InputInfo &II) {
+ if (!OutputCorpus.empty() && II.MayDeleteFile)
+ RemoveFile(DirPlusFile(OutputCorpus, Sha1ToString(II.Sha1)));
+ }
+
+ void DeleteInput(size_t Idx) {
+ InputInfo &II = *Inputs[Idx];
+ DeleteFile(II);
+ Unit().swap(II.U);
+ II.Energy = 0.0;
+ II.NeedsEnergyUpdate = false;
+ DistributionNeedsUpdate = true;
+ if (FeatureDebug)
+ Printf("EVICTED %zd\n", Idx);
+ }
+
+ void AddRareFeature(uint32_t Idx) {
+ // Maintain *at least* TopXRarestFeatures many rare features
+ // and all features with a frequency below ConsideredRare.
+ // Remove all other features.
+ while (RareFeatures.size() > Entropic.NumberOfRarestFeatures &&
+ FreqOfMostAbundantRareFeature > Entropic.FeatureFrequencyThreshold) {
+
+ // Find most and second most abbundant feature.
+ uint32_t MostAbundantRareFeatureIndices[2] = {RareFeatures[0],
+ RareFeatures[0]};
+ size_t Delete = 0;
+ for (size_t i = 0; i < RareFeatures.size(); i++) {
+ uint32_t Idx2 = RareFeatures[i];
+ if (GlobalFeatureFreqs[Idx2] >=
+ GlobalFeatureFreqs[MostAbundantRareFeatureIndices[0]]) {
+ MostAbundantRareFeatureIndices[1] = MostAbundantRareFeatureIndices[0];
+ MostAbundantRareFeatureIndices[0] = Idx2;
+ Delete = i;
+ }
+ }
+
+ // Remove most abundant rare feature.
+ RareFeatures[Delete] = RareFeatures.back();
+ RareFeatures.pop_back();
+
+ for (auto II : Inputs) {
+ if (II->DeleteFeatureFreq(MostAbundantRareFeatureIndices[0]))
+ II->NeedsEnergyUpdate = true;
+ }
+
+ // Set 2nd most abundant as the new most abundant feature count.
+ FreqOfMostAbundantRareFeature =
+ GlobalFeatureFreqs[MostAbundantRareFeatureIndices[1]];
+ }
+
+ // Add rare feature, handle collisions, and update energy.
+ RareFeatures.push_back(Idx);
+ GlobalFeatureFreqs[Idx] = 0;
+ for (auto II : Inputs) {
+ II->DeleteFeatureFreq(Idx);
+
+ // Apply add-one smoothing to this locally undiscovered feature.
+ // Zero energy seeds will never be fuzzed and remain zero energy.
+ if (II->Energy > 0.0) {
+ II->SumIncidence += 1;
+ II->Energy += logl(II->SumIncidence) / II->SumIncidence;
+ }
+ }
+
+ DistributionNeedsUpdate = true;
+ }
+
+ bool AddFeature(size_t Idx, uint32_t NewSize, bool Shrink) {
+ assert(NewSize);
+ Idx = Idx % kFeatureSetSize;
+ uint32_t OldSize = GetFeature(Idx);
+ if (OldSize == 0 || (Shrink && OldSize > NewSize)) {
+ if (OldSize > 0) {
+ size_t OldIdx = SmallestElementPerFeature[Idx];
+ InputInfo &II = *Inputs[OldIdx];
+ assert(II.NumFeatures > 0);
+ II.NumFeatures--;
+ if (II.NumFeatures == 0)
+ DeleteInput(OldIdx);
+ } else {
+ NumAddedFeatures++;
+ if (Entropic.Enabled)
+ AddRareFeature((uint32_t)Idx);
+ }
+ NumUpdatedFeatures++;
+ if (FeatureDebug)
+ Printf("ADD FEATURE %zd sz %d\n", Idx, NewSize);
+ SmallestElementPerFeature[Idx] = Inputs.size();
+ InputSizesPerFeature[Idx] = NewSize;
+ return true;
+ }
+ return false;
+ }
+
+ // Increment frequency of feature Idx globally and locally.
+ void UpdateFeatureFrequency(InputInfo *II, size_t Idx) {
+ uint32_t Idx32 = Idx % kFeatureSetSize;
+
+ // Saturated increment.
+ if (GlobalFeatureFreqs[Idx32] == 0xFFFF)
+ return;
+ uint16_t Freq = GlobalFeatureFreqs[Idx32]++;
+
+ // Skip if abundant.
+ if (Freq > FreqOfMostAbundantRareFeature ||
+ std::find(RareFeatures.begin(), RareFeatures.end(), Idx32) ==
+ RareFeatures.end())
+ return;
+
+ // Update global frequencies.
+ if (Freq == FreqOfMostAbundantRareFeature)
+ FreqOfMostAbundantRareFeature++;
+
+ // Update local frequencies.
+ if (II)
+ II->UpdateFeatureFrequency(Idx32);
+ }
+
+ size_t NumFeatures() const { return NumAddedFeatures; }
+ size_t NumFeatureUpdates() const { return NumUpdatedFeatures; }
+
+private:
+
+ static const bool FeatureDebug = false;
+
+ size_t GetFeature(size_t Idx) const { return InputSizesPerFeature[Idx]; }
+
+ void ValidateFeatureSet() {
+ if (FeatureDebug)
+ PrintFeatureSet();
+ for (size_t Idx = 0; Idx < kFeatureSetSize; Idx++)
+ if (GetFeature(Idx))
+ Inputs[SmallestElementPerFeature[Idx]]->Tmp++;
+ for (auto II: Inputs) {
+ if (II->Tmp != II->NumFeatures)
+ Printf("ZZZ %zd %zd\n", II->Tmp, II->NumFeatures);
+ assert(II->Tmp == II->NumFeatures);
+ II->Tmp = 0;
+ }
+ }
+
+ // Updates the probability distribution for the units in the corpus.
+ // Must be called whenever the corpus or unit weights are changed.
+ //
+ // Hypothesis: inputs that maximize information about globally rare features
+ // are interesting.
+ void UpdateCorpusDistribution(Random &Rand) {
+ // Skip update if no seeds or rare features were added/deleted.
+ // Sparse updates for local change of feature frequencies,
+ // i.e., randomly do not skip.
+ if (!DistributionNeedsUpdate &&
+ (!Entropic.Enabled || Rand(kSparseEnergyUpdates)))
+ return;
+
+ DistributionNeedsUpdate = false;
+
+ size_t N = Inputs.size();
+ assert(N);
+ Intervals.resize(N + 1);
+ Weights.resize(N);
+ std::iota(Intervals.begin(), Intervals.end(), 0);
+
+ bool VanillaSchedule = true;
+ if (Entropic.Enabled) {
+ for (auto II : Inputs) {
+ if (II->NeedsEnergyUpdate && II->Energy != 0.0) {
+ II->NeedsEnergyUpdate = false;
+ II->UpdateEnergy(RareFeatures.size());
+ }
+ }
+
+ for (size_t i = 0; i < N; i++) {
+
+ if (Inputs[i]->NumFeatures == 0) {
+ // If the seed doesn't represent any features, assign zero energy.
+ Weights[i] = 0.;
+ } else if (Inputs[i]->NumExecutedMutations / kMaxMutationFactor >
+ NumExecutedMutations / Inputs.size()) {
+ // If the seed was fuzzed a lot more than average, assign zero energy.
+ Weights[i] = 0.;
+ } else {
+ // Otherwise, simply assign the computed energy.
+ Weights[i] = Inputs[i]->Energy;
+ }
+
+ // If energy for all seeds is zero, fall back to vanilla schedule.
+ if (Weights[i] > 0.0)
+ VanillaSchedule = false;
+ }
+ }
+
+ if (VanillaSchedule) {
+ for (size_t i = 0; i < N; i++)
+ Weights[i] = Inputs[i]->NumFeatures
+ ? (i + 1) * (Inputs[i]->HasFocusFunction ? 1000 : 1)
+ : 0.;
+ }
+
+ if (FeatureDebug) {
+ for (size_t i = 0; i < N; i++)
+ Printf("%zd ", Inputs[i]->NumFeatures);
+ Printf("SCORE\n");
+ for (size_t i = 0; i < N; i++)
+ Printf("%f ", Weights[i]);
+ Printf("Weights\n");
+ }
+ CorpusDistribution = std::piecewise_constant_distribution<double>(
+ Intervals.begin(), Intervals.end(), Weights.begin());
+ }
+ std::piecewise_constant_distribution<double> CorpusDistribution;
+
+ Vector<double> Intervals;
+ Vector<double> Weights;
+
+ std::unordered_set<std::string> Hashes;
+ Vector<InputInfo*> Inputs;
+
+ size_t NumAddedFeatures = 0;
+ size_t NumUpdatedFeatures = 0;
+ uint32_t InputSizesPerFeature[kFeatureSetSize];
+ uint32_t SmallestElementPerFeature[kFeatureSetSize];
+
+ bool DistributionNeedsUpdate = true;
+ uint16_t FreqOfMostAbundantRareFeature = 0;
+ uint16_t GlobalFeatureFreqs[kFeatureSetSize] = {};
+ Vector<uint32_t> RareFeatures;
+
+ std::string OutputCorpus;
+};
+
+} // namespace fuzzer
+
+#endif // LLVM_FUZZER_CORPUS