json/tests/thirdparty/Fuzzer/FuzzerTraceState.cpp
Niels Lohmann b21c345179
Reorganize directories (#3462)
* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests
2022-05-01 09:41:50 +02:00

326 lines
11 KiB
C++

//===- FuzzerTraceState.cpp - Trace-based fuzzer mutator ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Data tracing.
//===----------------------------------------------------------------------===//
#include "FuzzerDictionary.h"
#include "FuzzerInternal.h"
#include "FuzzerIO.h"
#include "FuzzerMutate.h"
#include "FuzzerRandom.h"
#include "FuzzerTracePC.h"
#include <algorithm>
#include <cstring>
#include <map>
#include <set>
#include <thread>
namespace fuzzer {
// For now, very simple: put Size bytes of Data at position Pos.
struct TraceBasedMutation {
uint32_t Pos;
Word W;
};
// Declared as static globals for faster checks inside the hooks.
static bool RecordingMemcmp = false;
static bool RecordingMemmem = false;
static bool DoingMyOwnMemmem = false;
ScopedDoingMyOwnMemmem::ScopedDoingMyOwnMemmem() { DoingMyOwnMemmem = true; }
ScopedDoingMyOwnMemmem::~ScopedDoingMyOwnMemmem() { DoingMyOwnMemmem = false; }
class TraceState {
public:
TraceState(MutationDispatcher &MD, const FuzzingOptions &Options,
const Fuzzer *F)
: MD(MD), Options(Options), F(F) {}
void TraceMemcmpCallback(size_t CmpSize, const uint8_t *Data1,
const uint8_t *Data2);
void TraceSwitchCallback(uintptr_t PC, size_t ValSizeInBits, uint64_t Val,
size_t NumCases, uint64_t *Cases);
int TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
size_t DataSize);
int TryToAddDesiredData(const uint8_t *PresentData,
const uint8_t *DesiredData, size_t DataSize);
void StartTraceRecording() {
if (!Options.UseMemcmp)
return;
RecordingMemcmp = Options.UseMemcmp;
RecordingMemmem = Options.UseMemmem;
NumMutations = 0;
InterestingWords.clear();
MD.ClearAutoDictionary();
}
void StopTraceRecording() {
if (!RecordingMemcmp)
return;
RecordingMemcmp = false;
for (size_t i = 0; i < NumMutations; i++) {
auto &M = Mutations[i];
if (Options.Verbosity >= 2) {
AutoDictUnitCounts[M.W]++;
AutoDictAdds++;
if ((AutoDictAdds & (AutoDictAdds - 1)) == 0) {
typedef std::pair<size_t, Word> CU;
std::vector<CU> CountedUnits;
for (auto &I : AutoDictUnitCounts)
CountedUnits.push_back(std::make_pair(I.second, I.first));
std::sort(CountedUnits.begin(), CountedUnits.end(),
[](const CU &a, const CU &b) { return a.first > b.first; });
Printf("AutoDict:\n");
for (auto &I : CountedUnits) {
Printf(" %zd ", I.first);
PrintASCII(I.second.data(), I.second.size());
Printf("\n");
}
}
}
MD.AddWordToAutoDictionary({M.W, M.Pos});
}
for (auto &W : InterestingWords)
MD.AddWordToAutoDictionary({W});
}
void AddMutation(uint32_t Pos, uint32_t Size, const uint8_t *Data) {
if (NumMutations >= kMaxMutations) return;
auto &M = Mutations[NumMutations++];
M.Pos = Pos;
M.W.Set(Data, Size);
}
void AddMutation(uint32_t Pos, uint32_t Size, uint64_t Data) {
assert(Size <= sizeof(Data));
AddMutation(Pos, Size, reinterpret_cast<uint8_t*>(&Data));
}
void AddInterestingWord(const uint8_t *Data, size_t Size) {
if (!RecordingMemmem || !F->InFuzzingThread()) return;
if (Size <= 1) return;
Size = std::min(Size, Word::GetMaxSize());
Word W(Data, Size);
InterestingWords.insert(W);
}
private:
bool IsTwoByteData(uint64_t Data) {
int64_t Signed = static_cast<int64_t>(Data);
Signed >>= 16;
return Signed == 0 || Signed == -1L;
}
// We don't want to create too many trace-based mutations as it is both
// expensive and useless. So after some number of mutations is collected,
// start rejecting some of them. The more there are mutations the more we
// reject.
bool WantToHandleOneMoreMutation() {
const size_t FirstN = 64;
// Gladly handle first N mutations.
if (NumMutations <= FirstN) return true;
size_t Diff = NumMutations - FirstN;
size_t DiffLog = sizeof(long) * 8 - __builtin_clzl((long)Diff);
assert(DiffLog > 0 && DiffLog < 64);
bool WantThisOne = MD.GetRand()(1 << DiffLog) == 0; // 1 out of DiffLog.
return WantThisOne;
}
static const size_t kMaxMutations = 1 << 16;
size_t NumMutations;
TraceBasedMutation Mutations[kMaxMutations];
// TODO: std::set is too inefficient, need to have a custom DS here.
std::set<Word> InterestingWords;
MutationDispatcher &MD;
const FuzzingOptions Options;
const Fuzzer *F;
std::map<Word, size_t> AutoDictUnitCounts;
size_t AutoDictAdds = 0;
};
int TraceState::TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
size_t DataSize) {
if (NumMutations >= kMaxMutations || !WantToHandleOneMoreMutation()) return 0;
ScopedDoingMyOwnMemmem scoped_doing_my_own_memmem;
const uint8_t *UnitData;
auto UnitSize = F->GetCurrentUnitInFuzzingThead(&UnitData);
int Res = 0;
const uint8_t *Beg = UnitData;
const uint8_t *End = Beg + UnitSize;
for (const uint8_t *Cur = Beg; Cur < End; Cur++) {
Cur = (uint8_t *)SearchMemory(Cur, End - Cur, &PresentData, DataSize);
if (!Cur)
break;
size_t Pos = Cur - Beg;
assert(Pos < UnitSize);
AddMutation(Pos, DataSize, DesiredData);
AddMutation(Pos, DataSize, DesiredData + 1);
AddMutation(Pos, DataSize, DesiredData - 1);
Res++;
}
return Res;
}
int TraceState::TryToAddDesiredData(const uint8_t *PresentData,
const uint8_t *DesiredData,
size_t DataSize) {
if (NumMutations >= kMaxMutations || !WantToHandleOneMoreMutation()) return 0;
ScopedDoingMyOwnMemmem scoped_doing_my_own_memmem;
const uint8_t *UnitData;
auto UnitSize = F->GetCurrentUnitInFuzzingThead(&UnitData);
int Res = 0;
const uint8_t *Beg = UnitData;
const uint8_t *End = Beg + UnitSize;
for (const uint8_t *Cur = Beg; Cur < End; Cur++) {
Cur = (uint8_t *)SearchMemory(Cur, End - Cur, PresentData, DataSize);
if (!Cur)
break;
size_t Pos = Cur - Beg;
assert(Pos < UnitSize);
AddMutation(Pos, DataSize, DesiredData);
Res++;
}
return Res;
}
void TraceState::TraceMemcmpCallback(size_t CmpSize, const uint8_t *Data1,
const uint8_t *Data2) {
if (!RecordingMemcmp || !F->InFuzzingThread()) return;
CmpSize = std::min(CmpSize, Word::GetMaxSize());
int Added2 = TryToAddDesiredData(Data1, Data2, CmpSize);
int Added1 = TryToAddDesiredData(Data2, Data1, CmpSize);
if ((Added1 || Added2) && Options.Verbosity >= 3) {
Printf("MemCmp Added %d%d: ", Added1, Added2);
if (Added1) PrintASCII(Data1, CmpSize);
if (Added2) PrintASCII(Data2, CmpSize);
Printf("\n");
}
}
void TraceState::TraceSwitchCallback(uintptr_t PC, size_t ValSizeInBits,
uint64_t Val, size_t NumCases,
uint64_t *Cases) {
if (F->InFuzzingThread()) return;
size_t ValSize = ValSizeInBits / 8;
bool TryShort = IsTwoByteData(Val);
for (size_t i = 0; i < NumCases; i++)
TryShort &= IsTwoByteData(Cases[i]);
if (Options.Verbosity >= 3)
Printf("TraceSwitch: %p %zd # %zd; TryShort %d\n", PC, Val, NumCases,
TryShort);
for (size_t i = 0; i < NumCases; i++) {
TryToAddDesiredData(Val, Cases[i], ValSize);
if (TryShort)
TryToAddDesiredData(Val, Cases[i], 2);
}
}
static TraceState *TS;
void Fuzzer::StartTraceRecording() {
if (!TS) return;
TS->StartTraceRecording();
}
void Fuzzer::StopTraceRecording() {
if (!TS) return;
TS->StopTraceRecording();
}
void Fuzzer::InitializeTraceState() {
if (!Options.UseMemcmp) return;
TS = new TraceState(MD, Options, this);
}
static size_t InternalStrnlen(const char *S, size_t MaxLen) {
size_t Len = 0;
for (; Len < MaxLen && S[Len]; Len++) {}
return Len;
}
} // namespace fuzzer
using fuzzer::TS;
using fuzzer::RecordingMemcmp;
extern "C" {
// We may need to avoid defining weak hooks to stay compatible with older clang.
#ifndef LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
# define LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS 1
#endif
#if LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
void __sanitizer_weak_hook_memcmp(void *caller_pc, const void *s1,
const void *s2, size_t n, int result) {
fuzzer::TPC.AddValueForMemcmp(caller_pc, s1, s2, n);
if (!RecordingMemcmp) return;
if (result == 0) return; // No reason to mutate.
if (n <= 1) return; // Not interesting.
TS->TraceMemcmpCallback(n, reinterpret_cast<const uint8_t *>(s1),
reinterpret_cast<const uint8_t *>(s2));
}
void __sanitizer_weak_hook_strncmp(void *caller_pc, const char *s1,
const char *s2, size_t n, int result) {
fuzzer::TPC.AddValueForStrcmp(caller_pc, s1, s2, n);
if (!RecordingMemcmp) return;
if (result == 0) return; // No reason to mutate.
size_t Len1 = fuzzer::InternalStrnlen(s1, n);
size_t Len2 = fuzzer::InternalStrnlen(s2, n);
n = std::min(n, Len1);
n = std::min(n, Len2);
if (n <= 1) return; // Not interesting.
TS->TraceMemcmpCallback(n, reinterpret_cast<const uint8_t *>(s1),
reinterpret_cast<const uint8_t *>(s2));
}
void __sanitizer_weak_hook_strcmp(void *caller_pc, const char *s1,
const char *s2, int result) {
fuzzer::TPC.AddValueForStrcmp(caller_pc, s1, s2, 64);
if (!RecordingMemcmp) return;
if (result == 0) return; // No reason to mutate.
size_t Len1 = strlen(s1);
size_t Len2 = strlen(s2);
size_t N = std::min(Len1, Len2);
if (N <= 1) return; // Not interesting.
TS->TraceMemcmpCallback(N, reinterpret_cast<const uint8_t *>(s1),
reinterpret_cast<const uint8_t *>(s2));
}
void __sanitizer_weak_hook_strncasecmp(void *called_pc, const char *s1,
const char *s2, size_t n, int result) {
return __sanitizer_weak_hook_strncmp(called_pc, s1, s2, n, result);
}
void __sanitizer_weak_hook_strcasecmp(void *called_pc, const char *s1,
const char *s2, int result) {
return __sanitizer_weak_hook_strcmp(called_pc, s1, s2, result);
}
void __sanitizer_weak_hook_strstr(void *called_pc, const char *s1,
const char *s2, char *result) {
TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
}
void __sanitizer_weak_hook_strcasestr(void *called_pc, const char *s1,
const char *s2, char *result) {
TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
}
void __sanitizer_weak_hook_memmem(void *called_pc, const void *s1, size_t len1,
const void *s2, size_t len2, void *result) {
if (fuzzer::DoingMyOwnMemmem) return;
TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), len2);
}
#endif // LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
} // extern "C"