| commit | c020de1c1cf35fc1621df584177f532c07f8eaef | [log] [tgz] |
|---|---|---|
| author | Vitaly Buka <vitalybuka@google.com> | Fri Mar 03 19:36:23 2017 -0800 |
| committer | Vitaly Buka <vitalybuka@gmail.com> | Sat Mar 04 11:36:56 2017 -0800 |
| tree | 1b29ac8473f014a821bc0e3d038a0cf91f834a1b | |
| parent | 796b1121f90edf33fdaffab0c11895788594ae27 [diff] |
Make MutateString overrides always return new values.
libprotobuf-mutator is a library to randomly mutate protobuffers.
It could be used together with guided fuzzing engines, such as libFuzzer.
Install prerequisites:
sudo apt-get update sudo apt-get install binutils cmake ninja-build liblzma-dev libz-dev docbook2x
Compile and test everything:
mkdir build cd build cmake .. -GNinja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Debug ninja check
Clang is only needed for libFuzzer integration.
To use libprotobuf-mutator simply include protobuf_mutator.h and protobuf_mutator.cc into your build files.
The ProtobufMutator class implements mutations of the protobuf tree structure and mutations of individual fields. The field mutation logic is very basic -- for better results you should override the ProtobufMutator::Mutate* methods with more sophisticated logic, e.g. using libFuzzer's mutators.
To apply one mutation to a protobuf object do the following:
class MyProtobufMutator : public ProtobufMutator {
public:
MyProtobufMutator(uint32_t seed) : ProtobufMutator(seed) {}
// Optionally redefine the Mutate* methods to perform more sophisticated mutations.
}
void Mutate(MyMessage* message) {
MyProtobufMutator mutator(my_random_seed);
mutator.Mutate(message, 200);
}
See also the ProtobufMutatorMessagesTest.UsageExample test from protobuf_mutator_test.cc.
LibFuzzerProtobufMutator can help to integrate with libFuzzer. For example
#include "libfuzzer_protobuf_mutator.h"
extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* data, size_t size,
size_t max_size, unsigned int seed) {
return protobuf_mutator::MutateTextMessage<MyMessageType>(
data, size, max_size, seed);
}
extern "C" size_t LLVMFuzzerCustomCrossOver(const uint8_t* data1, size_t size1,
const uint8_t* data2, size_t size2,
uint8_t* out, size_t max_out_size,
unsigned int seed) {
return protobuf_mutator::CrossOverTextMessages<MyMessageType>(
data1, size1, data2, size2, out, max_out_size, seed);
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
MyMessageType message;
protobuf_mutator::ParseTextMessage(data, size, &message);
// Code which needs to be fuzzed.
ConsumeMyMessageType(message);
return 0;
}
Please see libfuzzer_example.cc as an example.