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[lib/Fuzzer] add a trace-based mutatation logic. Same idea as with DFSan-based mutator, but instead of relying on taint tracking, try to find the data directly in the input. More (logic and comments) to go.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237043 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kostya Serebryany
2015-05-11 20:51:19 +00:00
parent a1945939bd
commit 0cdb698aae
5 changed files with 69 additions and 13 deletions
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78
lib/Fuzzer/FuzzerDFSan.cpp
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@@ -85,7 +85,11 @@ __attribute__((weak))
dfsan_label dfsan_read_label(const void *addr, size_t size);
} // extern "C"
namespace {
namespace fuzzer {
static bool ReallyHaveDFSan() {
return &dfsan_create_label != nullptr;
}
// These values are copied from include/llvm/IR/InstrTypes.h.
// We do not include the LLVM headers here to remain independent.
@@ -166,13 +170,17 @@ struct TraceBasedMutation {
class DFSanState {
public:
DFSanState(const fuzzer::Fuzzer::FuzzingOptions &Options)
: Options(Options) {}
DFSanState(const Fuzzer::FuzzingOptions &Options, const Unit &CurrentUnit)
: Options(Options), CurrentUnit(CurrentUnit) {}
LabelRange GetLabelRange(dfsan_label L);
void DFSanCmpCallback(uintptr_t PC, size_t CmpSize, size_t CmpType,
uint64_t Arg1, uint64_t Arg2, dfsan_label L1,
dfsan_label L2);
void TraceCmpCallback(size_t CmpSize, size_t CmpType, uint64_t Arg1,
uint64_t Arg2);
int TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
size_t DataSize);
void StartTraceRecording() {
RecordingTraces = true;
@@ -188,10 +196,16 @@ class DFSanState {
void ApplyTraceBasedMutation(size_t Idx, fuzzer::Unit *U);
private:
bool IsTwoByteData(uint64_t Data) {
int64_t Signed = static_cast<int64_t>(Data);
Signed >>= 16;
return Signed == 0 || Signed == -1L;
}
bool RecordingTraces = false;
std::vector<TraceBasedMutation> Mutations;
LabelRange LabelRanges[1 << (sizeof(dfsan_label) * 8)] = {};
const fuzzer::Fuzzer::FuzzingOptions &Options;
const Fuzzer::FuzzingOptions &Options;
const Unit &CurrentUnit;
};
LabelRange DFSanState::GetLabelRange(dfsan_label L) {
@@ -216,6 +230,7 @@ void DFSanState::ApplyTraceBasedMutation(size_t Idx, fuzzer::Unit *U) {
void DFSanState::DFSanCmpCallback(uintptr_t PC, size_t CmpSize, size_t CmpType,
uint64_t Arg1, uint64_t Arg2, dfsan_label L1,
dfsan_label L2) {
assert(ReallyHaveDFSan());
if (!RecordingTraces) return;
if (L1 == 0 && L2 == 0)
return; // Not actionable.
@@ -248,12 +263,43 @@ void DFSanState::DFSanCmpCallback(uintptr_t PC, size_t CmpSize, size_t CmpType,
<< "\n";
}
int DFSanState::TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
size_t DataSize) {
int Res = 0;
const uint8_t *Beg = CurrentUnit.data();
const uint8_t *End = Beg + CurrentUnit.size();
for (const uint8_t *Cur = Beg; Cur < End; Cur += DataSize) {
Cur = (uint8_t *)memmem(Cur, End - Cur, &PresentData, DataSize);
if (!Cur)
break;
// std::cerr << "Cur " << (void*)Cur << "\n";
size_t Pos = Cur - Beg;
assert(Pos < CurrentUnit.size());
Mutations.push_back({Pos, DataSize, DesiredData});
Mutations.push_back({Pos, DataSize, DesiredData + 1});
Mutations.push_back({Pos, DataSize, DesiredData - 1});
Cur += DataSize;
Res++;
}
return Res;
}
void DFSanState::TraceCmpCallback(size_t CmpSize, size_t CmpType, uint64_t Arg1,
uint64_t Arg2) {
if (!Options.UseTraces) return;
int Added = 0;
if (Options.Verbosity >= 3)
std::cerr << "TraceCmp: " << Arg1 << " " << Arg2 << "\n";
Added += TryToAddDesiredData(Arg1, Arg2, CmpSize);
Added += TryToAddDesiredData(Arg2, Arg1, CmpSize);
if (!Added && CmpSize == 4 && IsTwoByteData(Arg1) && IsTwoByteData(Arg2)) {
Added += TryToAddDesiredData(Arg1, Arg2, 2);
Added += TryToAddDesiredData(Arg2, Arg1, 2);
}
}
static DFSanState *DFSan;
} // namespace
namespace fuzzer {
void Fuzzer::StartTraceRecording() {
if (!DFSan) return;
DFSan->StartTraceRecording();
@@ -270,9 +316,11 @@ void Fuzzer::ApplyTraceBasedMutation(size_t Idx, Unit *U) {
}
void Fuzzer::InitializeDFSan() {
if (!&dfsan_create_label || !Options.UseDFSan) return;
DFSan = new DFSanState(Options);
if (!Options.UseDFSan) return;
DFSan = new DFSanState(Options, CurrentUnit);
CurrentUnit.resize(Options.MaxLen);
// The rest really requires DFSan.
if (!ReallyHaveDFSan()) return;
for (size_t i = 0; i < static_cast<size_t>(Options.MaxLen); i++) {
dfsan_label L = dfsan_create_label("input", (void*)(i + 1));
// We assume that no one else has called dfsan_create_label before.
@@ -283,6 +331,8 @@ void Fuzzer::InitializeDFSan() {
} // namespace fuzzer
using fuzzer::DFSan;
extern "C" {
void __dfsw___sanitizer_cov_trace_cmp(uint64_t SizeAndType, uint64_t Arg1,
uint64_t Arg2, dfsan_label L0,
@@ -304,13 +354,15 @@ void dfsan_weak_hook_memcmp(void *caller_pc, const void *s1, const void *s2,
memcpy(&S2, s2, std::min(n, sizeof(S2)));
dfsan_label L1 = dfsan_read_label(s1, n);
dfsan_label L2 = dfsan_read_label(s2, n);
DFSan->DFSanCmpCallback(PC, n, ICMP_EQ, S1, S2, L1, L2);
DFSan->DFSanCmpCallback(PC, n, fuzzer::ICMP_EQ, S1, S2, L1, L2);
}
void __sanitizer_cov_trace_cmp(uint64_t SizeAndType, uint64_t Arg1,
uint64_t Arg2) {
// This symbol will be present if dfsan is disabled on the given function.
// FIXME: implement poor man's taint analysis here (w/o dfsan).
if (!DFSan) return;
uint64_t CmpSize = (SizeAndType >> 32) / 8;
uint64_t Type = (SizeAndType << 32) >> 32;
DFSan->TraceCmpCallback(CmpSize, Type, Arg1, Arg2);
}
} // extern "C"

1
lib/Fuzzer/FuzzerDriver.cpp
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@@ -201,6 +201,7 @@ int FuzzerDriver(int argc, char **argv, UserCallback Callback) {
Options.MutateDepth = Flags.mutate_depth;
Options.ExitOnFirst = Flags.exit_on_first;
Options.UseCounters = Flags.use_counters;
Options.UseTraces = Flags.use_traces;
Options.UseFullCoverageSet = Flags.use_full_coverage_set;
Options.UseCoveragePairs = Flags.use_coverage_pairs;
Options.UseDFSan = Flags.dfsan;

1
lib/Fuzzer/FuzzerFlags.def
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@@ -33,6 +33,7 @@ FUZZER_FLAG_INT(
save_minimized_corpus, 0,
"If 1, the minimized corpus is saved into the first input directory")
FUZZER_FLAG_INT(use_counters, 0, "Use coverage counters")
FUZZER_FLAG_INT(use_traces, 0, "Experimental: use instruction traces")
FUZZER_FLAG_INT(use_full_coverage_set, 0,
"Experimental: Maximize the number of different full"
" coverage sets as opposed to maximizing the total coverage."

1
lib/Fuzzer/FuzzerInternal.h
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@@ -53,6 +53,7 @@ class Fuzzer {
int MutateDepth = 5;
bool ExitOnFirst = false;
bool UseCounters = false;
bool UseTraces = false;
bool UseFullCoverageSet = false;
bool UseCoveragePairs = false;
bool UseDFSan = false;

1
lib/Fuzzer/test/fuzzer.test
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@@ -20,6 +20,7 @@ RUN: not ./LLVMFuzzer-FourIndependentBranchesTest -timeout=15 -seed=1 -use_cover
RUN: not ./LLVMFuzzer-CounterTest -use_counters=1 -max_len=6 -seed=1 -timeout=15 2>&1 | FileCheck %s
RUN: not ./LLVMFuzzer-DFSanSimpleCmpTest-DFSan -seed=1 -runs=1000000 -timeout=5 2>&1 | FileCheck %s
RUN: not ./LLVMFuzzer-DFSanSimpleCmpTest -use_traces=1 -seed=1 -runs=1000000 -timeout=5 2>&1 | FileCheck %s
RUN: not ./LLVMFuzzer-DFSanMemcmpTest-DFSan -seed=1 -runs=100 -timeout=5 2>&1 | FileCheck %s