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/*
* Copyright 2020 Google Inc.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "libprotobuf-mutator/src/libfuzzer/libfuzzer_macro.h"
#include "png_fuzz_proto.pb.h"
template <typename Proto>
using FuzzMutatorCallback = std::function<void(Proto*, unsigned int)>;
template <typename Proto>
struct PngProtoCBRegistration
{
PngProtoCBRegistration(FuzzMutatorCallback<Proto> const& _callback)
{
static protobuf_mutator::libfuzzer::PostProcessorRegistration<Proto> reg = {_callback};
}
};
/// Custom mutation: Otherchunk unknown_type -> known_type
static PngProtoCBRegistration<OtherChunk> addCustomChunk = {
[](OtherChunk* message, unsigned int seed)
{
// Mutate with a probability of roughly 1/47
// 47 has been chosen ad-hoc
if (seed % 47 == 0)
{
// If otherChunk is unknown type, mutate
// it to known type
if (message->has_unknown_type())
{
// This is our custom mutation
// We assume (k * 47 mod N) distribute
// uniformly, where
// - N is total number of known
// chunks defined by png proto converter
// - k is a factor of seed
message->set_known_type(seed);
}
}
}
};