[llvm] r238059 - [lib/Fuzzer] extend the fuzzer interface to allow user-supplied mutators
Kostya Serebryany
kcc at google.com
Fri May 22 15:35:31 PDT 2015
Author: kcc
Date: Fri May 22 17:35:31 2015
New Revision: 238059
URL: http://llvm.org/viewvc/llvm-project?rev=238059&view=rev
Log:
[lib/Fuzzer] extend the fuzzer interface to allow user-supplied mutators
Added:
llvm/trunk/lib/Fuzzer/FuzzerInterface.cpp
llvm/trunk/lib/Fuzzer/test/UserSuppliedFuzzerTest.cpp
Modified:
llvm/trunk/lib/Fuzzer/CMakeLists.txt
llvm/trunk/lib/Fuzzer/FuzzerCrossOver.cpp
llvm/trunk/lib/Fuzzer/FuzzerDriver.cpp
llvm/trunk/lib/Fuzzer/FuzzerInterface.h
llvm/trunk/lib/Fuzzer/FuzzerInternal.h
llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp
llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp
llvm/trunk/lib/Fuzzer/test/CMakeLists.txt
llvm/trunk/lib/Fuzzer/test/FuzzerUnittest.cpp
llvm/trunk/lib/Fuzzer/test/fuzzer.test
Modified: llvm/trunk/lib/Fuzzer/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/CMakeLists.txt?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/CMakeLists.txt (original)
+++ llvm/trunk/lib/Fuzzer/CMakeLists.txt Fri May 22 17:35:31 2015
@@ -2,8 +2,9 @@ set(LIBFUZZER_FLAGS_BASE "${CMAKE_CXX_FL
# Disable the coverage and sanitizer instrumentation for the fuzzer itself.
set(CMAKE_CXX_FLAGS_RELEASE "${LIBFUZZER_FLAGS_BASE} -O2 -fno-sanitize=all")
if( LLVM_USE_SANITIZE_COVERAGE )
- add_library(LLVMFuzzerNoMain OBJECT
+ add_library(LLVMFuzzerNoMainObjects OBJECT
FuzzerCrossOver.cpp
+ FuzzerInterface.cpp
FuzzerTraceState.cpp
FuzzerDriver.cpp
FuzzerIO.cpp
@@ -13,9 +14,12 @@ if( LLVM_USE_SANITIZE_COVERAGE )
FuzzerSHA1.cpp
FuzzerUtil.cpp
)
+ add_library(LLVMFuzzerNoMain STATIC
+ $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
+ )
add_library(LLVMFuzzer STATIC
FuzzerMain.cpp
- $<TARGET_OBJECTS:LLVMFuzzerNoMain>
+ $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
)
if( LLVM_INCLUDE_TESTS )
Modified: llvm/trunk/lib/Fuzzer/FuzzerCrossOver.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerCrossOver.cpp?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerCrossOver.cpp (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerCrossOver.cpp Fri May 22 17:35:31 2015
@@ -9,39 +9,42 @@
// Cross over test inputs.
//===----------------------------------------------------------------------===//
+#include <cstring>
+
#include "FuzzerInternal.h"
-#include <algorithm>
namespace fuzzer {
-// Cross A and B, store the result (ap to MaxLen bytes) in U.
-void CrossOver(const Unit &A, const Unit &B, Unit *U, size_t MaxLen) {
- size_t Size = rand() % MaxLen + 1;
- U->clear();
- const Unit *V = &A;
- size_t PosA = 0;
- size_t PosB = 0;
- size_t *Pos = &PosA;
- while (U->size() < Size && (PosA < A.size() || PosB < B.size())) {
- // Merge a part of V into U.
- size_t SizeLeftU = Size - U->size();
- if (*Pos < V->size()) {
- size_t SizeLeftV = V->size() - *Pos;
- size_t MaxExtraSize = std::min(SizeLeftU, SizeLeftV);
+// Cross Data1 and Data2, store the result (up to MaxOutSize bytes) in Out.
+size_t CrossOver(const uint8_t *Data1, size_t Size1,
+ const uint8_t *Data2, size_t Size2,
+ uint8_t *Out, size_t MaxOutSize) {
+ MaxOutSize = rand() % MaxOutSize + 1;
+ size_t OutPos = 0;
+ size_t Pos1 = 0;
+ size_t Pos2 = 0;
+ size_t *InPos = &Pos1;
+ size_t InSize = Size1;
+ const uint8_t *Data = Data1;
+ bool CurrentlyUsingFirstData = true;
+ while (OutPos < MaxOutSize && (Pos1 < Size1 || Pos2 < Size2)) {
+ // Merge a part of Data into Out.
+ size_t OutSizeLeft = MaxOutSize - OutPos;
+ if (*InPos < InSize) {
+ size_t InSizeLeft = InSize - *InPos;
+ size_t MaxExtraSize = std::min(OutSizeLeft, InSizeLeft);
size_t ExtraSize = rand() % MaxExtraSize + 1;
- U->insert(U->end(), V->begin() + *Pos, V->begin() + *Pos + ExtraSize);
- (*Pos) += ExtraSize;
- }
-
- // Use the other Unit on the next iteration.
- if (Pos == &PosA) {
- Pos = &PosB;
- V = &B;
- } else {
- Pos = &PosA;
- V = &A;
+ memcpy(Out + OutPos, Data + *InPos, ExtraSize);
+ OutPos += ExtraSize;
+ (*InPos) += ExtraSize;
}
+ // Use the other input data on the next iteration.
+ InPos = CurrentlyUsingFirstData ? &Pos2 : &Pos1;
+ InSize = CurrentlyUsingFirstData ? Size2 : Size1;
+ Data = CurrentlyUsingFirstData ? Data2 : Data1;
+ CurrentlyUsingFirstData = !CurrentlyUsingFirstData;
}
+ return OutPos;
}
} // namespace fuzzer
Modified: llvm/trunk/lib/Fuzzer/FuzzerDriver.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerDriver.cpp?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerDriver.cpp (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerDriver.cpp Fri May 22 17:35:31 2015
@@ -204,6 +204,11 @@ int ApplyTokens(const Fuzzer &F, const c
}
int FuzzerDriver(int argc, char **argv, UserCallback Callback) {
+ SimpleUserSuppliedFuzzer SUSF(Callback);
+ return FuzzerDriver(argc, argv, SUSF);
+}
+
+int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF) {
using namespace fuzzer;
ProgName = argv[0];
@@ -244,7 +249,7 @@ int FuzzerDriver(int argc, char **argv,
if (Flags.sync_command)
Options.SyncCommand = Flags.sync_command;
Options.SyncTimeout = Flags.sync_timeout;
- Fuzzer F(Callback, Options);
+ Fuzzer F(USF, Options);
unsigned seed = Flags.seed;
// Initialize seed.
Added: llvm/trunk/lib/Fuzzer/FuzzerInterface.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerInterface.cpp?rev=238059&view=auto
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerInterface.cpp (added)
+++ llvm/trunk/lib/Fuzzer/FuzzerInterface.cpp Fri May 22 17:35:31 2015
@@ -0,0 +1,27 @@
+//===- FuzzerInterface.cpp - Mutate a test input --------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Parts of public interface for libFuzzer.
+//===----------------------------------------------------------------------===//
+
+
+#include "FuzzerInterface.h"
+#include "FuzzerInternal.h"
+
+namespace fuzzer {
+size_t UserSuppliedFuzzer::BasicMutate(uint8_t *Data, size_t Size,
+ size_t MaxSize) {
+ return ::fuzzer::Mutate(Data, Size, MaxSize);
+}
+size_t UserSuppliedFuzzer::BasicCrossOver(const uint8_t *Data1, size_t Size1,
+ const uint8_t *Data2, size_t Size2,
+ uint8_t *Out, size_t MaxOutSize) {
+ return ::fuzzer::CrossOver(Data1, Size1, Data2, Size2, Out, MaxOutSize);
+}
+
+} // namespace fuzzer.
Modified: llvm/trunk/lib/Fuzzer/FuzzerInterface.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerInterface.h?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerInterface.h (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerInterface.h Fri May 22 17:35:31 2015
@@ -9,6 +9,10 @@
// Define the interface between the Fuzzer and the library being tested.
//===----------------------------------------------------------------------===//
+// WARNING: keep the interface free of STL or any other header-based C++ lib,
+// to avoid bad interactions between the code used in the fuzzer and
+// the code used in the target function.
+
#ifndef LLVM_FUZZER_INTERFACE_H
#define LLVM_FUZZER_INTERFACE_H
@@ -17,9 +21,69 @@
namespace fuzzer {
-typedef void (*UserCallback)(const uint8_t *data, size_t size);
+// Simple C-like interface with a single user-supplied callback.
+/* Usage: ---------------------------------------------------------------------
+#include "FuzzerInterface.h"
+
+void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+ DoStuffWithData(Data, Size);
+}
+
+// Implement your own main() or use the one from FuzzerMain.cpp.
+int main(int argc, char **argv) {
+ InitializeMeIfNeeded();
+ return fuzzer::FuzzerDriver(argc, argv, LLVMFuzzerTestOneInput);
+}
+----------------------------------------------------------------------------- */
+typedef void (*UserCallback)(const uint8_t *Data, size_t Size);
int FuzzerDriver(int argc, char **argv, UserCallback Callback);
+// An abstract class that allows to use user-supplied mutators with libFuzzer.
+/* Usage: ---------------------------------------------------------------------
+#include "FuzzerInterface.h"
+class MyFuzzer : public fuzzer::UserSuppliedFuzzer {
+ public:
+ // Must define the target function.
+ void TargetFunction(...) { ... }
+ // Optionally define the mutator.
+ size_t Mutate(...) { ... }
+ // Optionally define the CrossOver method.
+ size_t CrossOver(...) { ... }
+};
+
+int main(int argc, char **argv) {
+ MyFuzzer F;
+ fuzzer::FuzzerDriver(argc, argv, F);
+}
+----------------------------------------------------------------------------- */
+class UserSuppliedFuzzer {
+ public:
+ // Executes the target function on 'Size' bytes of 'Data'.
+ virtual void TargetFunction(const uint8_t *Data, size_t Size) = 0;
+ // Mutates 'Size' bytes of data in 'Data' inplace into up to 'MaxSize' bytes,
+ // returns the new size of the data.
+ virtual size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+ return BasicMutate(Data, Size, MaxSize);
+ }
+ // Crosses 'Data1' and 'Data2', writes up to 'MaxOutSize' bytes into Out,
+ // returns the number of bytes written.
+ virtual size_t CrossOver(const uint8_t *Data1, size_t Size1,
+ const uint8_t *Data2, size_t Size2,
+ uint8_t *Out, size_t MaxOutSize) {
+ return BasicCrossOver(Data1, Size1, Data2, Size2, Out, MaxOutSize);
+ }
+ virtual ~UserSuppliedFuzzer() {}
+
+ protected:
+ // These can be called internally by Mutate and CrossOver.
+ size_t BasicMutate(uint8_t *Data, size_t Size, size_t MaxSize);
+ size_t BasicCrossOver(const uint8_t *Data1, size_t Size1,
+ const uint8_t *Data2, size_t Size2,
+ uint8_t *Out, size_t MaxOutSize);
+};
+
+int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF);
+
} // namespace fuzzer
#endif // LLVM_FUZZER_INTERFACE_H
Modified: llvm/trunk/lib/Fuzzer/FuzzerInternal.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerInternal.h?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerInternal.h (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerInternal.h Fri May 22 17:35:31 2015
@@ -33,9 +33,10 @@ void CopyFileToErr(const std::string &Pa
std::string DirPlusFile(const std::string &DirPath,
const std::string &FileName);
-void Mutate(Unit *U, size_t MaxLen);
+size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize);
-void CrossOver(const Unit &A, const Unit &B, Unit *U, size_t MaxLen);
+size_t CrossOver(const uint8_t *Data1, size_t Size1, const uint8_t *Data2,
+ size_t Size2, uint8_t *Out, size_t MaxOutSize);
void Print(const Unit &U, const char *PrintAfter = "");
void PrintASCII(const Unit &U, const char *PrintAfter = "");
@@ -72,7 +73,7 @@ class Fuzzer {
std::string SyncCommand;
std::vector<std::string> Tokens;
};
- Fuzzer(UserCallback Callback, FuzzingOptions Options);
+ Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options);
void AddToCorpus(const Unit &U) { Corpus.push_back(U); }
void Loop(size_t NumIterations);
void ShuffleAndMinimize();
@@ -144,7 +145,7 @@ class Fuzzer {
return Res;
}
- UserCallback Callback;
+ UserSuppliedFuzzer &USF;
FuzzingOptions Options;
system_clock::time_point ProcessStartTime = system_clock::now();
system_clock::time_point LastExternalSync = system_clock::now();
@@ -153,4 +154,15 @@ class Fuzzer {
long EpochOfLastReadOfOutputCorpus = 0;
};
+class SimpleUserSuppliedFuzzer: public UserSuppliedFuzzer {
+ public:
+ SimpleUserSuppliedFuzzer(UserCallback Callback) : Callback(Callback) {}
+ virtual void TargetFunction(const uint8_t *Data, size_t Size) {
+ return Callback(Data, Size);
+ }
+
+ private:
+ UserCallback Callback;
+};
+
}; // namespace fuzzer
Modified: llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp Fri May 22 17:35:31 2015
@@ -19,8 +19,8 @@ namespace fuzzer {
// Only one Fuzzer per process.
static Fuzzer *F;
-Fuzzer::Fuzzer(UserCallback Callback, FuzzingOptions Options)
- : Callback(Callback), Options(Options) {
+Fuzzer::Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options)
+ : USF(USF), Options(Options) {
SetDeathCallback();
InitializeTraceState();
assert(!F);
@@ -207,10 +207,10 @@ Unit Fuzzer::SubstituteTokens(const Unit
void Fuzzer::ExecuteCallback(const Unit &U) {
if (Options.Tokens.empty()) {
- Callback(U.data(), U.size());
+ USF.TargetFunction(U.data(), U.size());
} else {
auto T = SubstituteTokens(U);
- Callback(T.data(), T.size());
+ USF.TargetFunction(T.data(), T.size());
}
}
@@ -321,7 +321,11 @@ void Fuzzer::ReportNewCoverage(size_t Ne
void Fuzzer::MutateAndTestOne(Unit *U) {
for (int i = 0; i < Options.MutateDepth; i++) {
StartTraceRecording();
- Mutate(U, Options.MaxLen);
+ size_t Size = U->size();
+ U->resize(Options.MaxLen);
+ size_t NewSize = USF.Mutate(U->data(), Size, U->size());
+ assert(NewSize > 0 && NewSize <= Options.MaxLen);
+ U->resize(NewSize);
RunOneAndUpdateCorpus(*U);
size_t NumTraceBasedMutations = StopTraceRecording();
for (size_t j = 0; j < NumTraceBasedMutations; j++) {
@@ -344,8 +348,12 @@ void Fuzzer::Loop(size_t NumIterations)
// Now, cross with others.
if (Options.DoCrossOver) {
for (size_t J2 = 0; J2 < Corpus.size(); J2++) {
- CurrentUnit.clear();
- CrossOver(Corpus[J1], Corpus[J2], &CurrentUnit, Options.MaxLen);
+ CurrentUnit.resize(Options.MaxLen);
+ size_t NewSize = USF.CrossOver(
+ Corpus[J1].data(), Corpus[J1].size(), Corpus[J2].data(),
+ Corpus[J2].size(), CurrentUnit.data(), CurrentUnit.size());
+ assert(NewSize > 0 && NewSize <= Options.MaxLen);
+ CurrentUnit.resize(NewSize);
MutateAndTestOne(&CurrentUnit);
}
}
Modified: llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp Fri May 22 17:35:31 2015
@@ -9,6 +9,8 @@
// Mutate a test input.
//===----------------------------------------------------------------------===//
+#include <cstring>
+
#include "FuzzerInternal.h"
namespace fuzzer {
@@ -31,40 +33,39 @@ static char RandCh() {
return Special[rand() % (sizeof(Special) - 1)];
}
-// Mutate U in place.
-void Mutate(Unit *U, size_t MaxLen) {
- assert(MaxLen > 0);
- assert(U->size() <= MaxLen);
- if (U->empty()) {
- for (size_t i = 0; i < MaxLen; i++)
- U->push_back(RandCh());
- return;
+// Mutates Data in place, returns new size.
+size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+ assert(MaxSize > 0);
+ assert(Size <= MaxSize);
+ if (Size == 0) {
+ for (size_t i = 0; i < MaxSize; i++)
+ Data[i] = RandCh();
+ return MaxSize;
}
- assert(!U->empty());
+ assert(Size > 0);
+ size_t Idx = rand() % Size;
switch (rand() % 3) {
case 0:
- if (U->size() > 1) {
- U->erase(U->begin() + rand() % U->size());
- break;
+ if (Size > 1) {
+ // Erase Data[Idx].
+ memmove(Data + Idx, Data + Idx + 1, Size - Idx - 1);
+ Size = Size - 1;
}
[[clang::fallthrough]];
case 1:
- if (U->size() < MaxLen) {
- U->insert(U->begin() + rand() % U->size(), RandCh());
- } else { // At MaxLen.
- uint8_t Ch = RandCh();
- size_t Idx = rand() % U->size();
- (*U)[Idx] = Ch;
+ if (Size < MaxSize) {
+ // Insert new value at Data[Idx].
+ memmove(Data + Idx + 1, Data + Idx, Size - Idx);
+ Data[Idx] = RandCh();
}
+ Data[Idx] = RandCh();
break;
- default:
- {
- size_t Idx = rand() % U->size();
- (*U)[Idx] = FlipRandomBit((*U)[Idx]);
- }
+ case 2:
+ Data[Idx] = FlipRandomBit(Data[Idx]);
break;
}
- assert(!U->empty());
+ assert(Size > 0);
+ return Size;
}
} // namespace fuzzer
Modified: llvm/trunk/lib/Fuzzer/test/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/CMakeLists.txt?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/CMakeLists.txt (original)
+++ llvm/trunk/lib/Fuzzer/test/CMakeLists.txt Fri May 22 17:35:31 2015
@@ -21,6 +21,10 @@ set(Tests
${DFSanTests}
)
+set(CustomMainTests
+ UserSuppliedFuzzerTest
+ )
+
set(TestBinaries)
@@ -34,6 +38,17 @@ foreach(Test ${Tests})
set(TestBinaries ${TestBinaries} LLVMFuzzer-${Test})
endforeach()
+foreach(Test ${CustomMainTests})
+ add_executable(LLVMFuzzer-${Test}
+ ${Test}.cpp
+ )
+ target_link_libraries(LLVMFuzzer-${Test}
+ LLVMFuzzerNoMain
+ )
+ set(TestBinaries ${TestBinaries} LLVMFuzzer-${Test})
+endforeach()
+
+
configure_lit_site_cfg(
${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
@@ -49,7 +64,7 @@ include_directories(${LLVM_MAIN_SRC_DIR}
add_executable(LLVMFuzzer-Unittest
FuzzerUnittest.cpp
- $<TARGET_OBJECTS:LLVMFuzzerNoMain>
+ $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
)
target_link_libraries(LLVMFuzzer-Unittest
Modified: llvm/trunk/lib/Fuzzer/test/FuzzerUnittest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/FuzzerUnittest.cpp?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/FuzzerUnittest.cpp (original)
+++ llvm/trunk/lib/Fuzzer/test/FuzzerUnittest.cpp Fri May 22 17:35:31 2015
@@ -51,7 +51,10 @@ TEST(Fuzzer, CrossOver) {
for (size_t Len = 1; Len < 8; Len++) {
std::set<Unit> FoundUnits, ExpectedUnitsWitThisLength;
for (int Iter = 0; Iter < 3000; Iter++) {
- CrossOver(A, B, &C, Len);
+ C.resize(Len);
+ size_t NewSize = CrossOver(A.data(), A.size(), B.data(), B.size(),
+ C.data(), C.size());
+ C.resize(NewSize);
FoundUnits.insert(C);
}
for (const Unit &U : Expected)
Added: llvm/trunk/lib/Fuzzer/test/UserSuppliedFuzzerTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/UserSuppliedFuzzerTest.cpp?rev=238059&view=auto
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/UserSuppliedFuzzerTest.cpp (added)
+++ llvm/trunk/lib/Fuzzer/test/UserSuppliedFuzzerTest.cpp Fri May 22 17:35:31 2015
@@ -0,0 +1,47 @@
+// Simple test for a fuzzer.
+// The fuzzer must find the string "Hi!" preceded by a magic value.
+// Uses UserSuppliedFuzzer which ensures that the magic is present.
+#include <cstdint>
+#include <cassert>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+
+#include "FuzzerInterface.h"
+
+static const uint64_t kMagic = 8860221463604ULL;
+
+class MyFuzzer : public fuzzer::UserSuppliedFuzzer {
+ public:
+ void TargetFunction(const uint8_t *Data, size_t Size) {
+ if (Size <= 10) return;
+ if (memcmp(Data, &kMagic, sizeof(kMagic))) return;
+ // It's hard to get here w/o advanced fuzzing techniques (e.g. cmp tracing).
+ // So, we simply 'fix' the data in the custom mutator.
+ if (Data[8] == 'H') {
+ if (Data[9] == 'i') {
+ if (Data[10] == '!') {
+ std::cout << "BINGO; Found the target, exiting\n";
+ exit(1);
+ }
+ }
+ }
+ }
+ // Custom mutator.
+ virtual size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+ assert(MaxSize > sizeof(kMagic));
+ if (Size < sizeof(kMagic))
+ Size = sizeof(kMagic);
+ // "Fix" the data, then mutate.
+ memcpy(Data, &kMagic, std::min(MaxSize, sizeof(kMagic)));
+ return BasicMutate(Data + sizeof(kMagic), Size - sizeof(kMagic),
+ MaxSize - sizeof(kMagic));
+ }
+ // No need to redefine CrossOver() here.
+};
+
+int main(int argc, char **argv) {
+ MyFuzzer F;
+ fuzzer::FuzzerDriver(argc, argv, F);
+}
Modified: llvm/trunk/lib/Fuzzer/test/fuzzer.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/fuzzer.test?rev=238059&r1=238058&r2=238059&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/fuzzer.test (original)
+++ llvm/trunk/lib/Fuzzer/test/fuzzer.test Fri May 22 17:35:31 2015
@@ -26,3 +26,5 @@ RUN: not ./LLVMFuzzer-DFSanMemcmpTest-DF
RUN: not ./LLVMFuzzer-CxxTokensTest -seed=1 -timeout=15 -tokens=%S/../cxx_fuzzer_tokens.txt 2>&1 | FileCheck %s
+RUN: not ./LLVMFuzzer-UserSuppliedFuzzerTest -seed=1 -timeout=15 2>&1 | FileCheck %s
+
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