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// Copyright 2019 The Pigweed Authors
//
// 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
//
// https://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 <pw_fuzzer/asan_interface.h>
#include <pw_fuzzer/fuzzed_data_provider.h>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <span>
#include <vector>
#include "pw_protobuf/encoder.h"
namespace {
// Encodable values. The fuzzer will iteratively choose different field types to
// generate and encode.
enum FieldType : uint8_t {
kEncodeAndClear = 0,
kUint32,
kPackedUint32,
kUint64,
kPackedUint64,
kInt32,
kPackedInt32,
kInt64,
kPackedInt64,
kSint32,
kPackedSint32,
kSint64,
kPackedSint64,
kBool,
kFixed32,
kPackedFixed32,
kFixed64,
kPackedFixed64,
kSfixed32,
kPackedSfixed32,
kSfixed64,
kPackedSfixed64,
kFloat,
kPackedFloat,
kDouble,
kPackedDouble,
kBytes,
kString,
kPush,
kPop,
kMaxValue = kPop,
};
// TODO(pwbug/181): Move this to pw_fuzzer/fuzzed_data_provider.h
// Uses the given |provider| to pick and return a number between 0 and the
// maximum numbers of T that can be generated from the remaining input data.
template <typename T>
size_t ConsumeSize(FuzzedDataProvider* provider) {
size_t max = provider->remaining_bytes() / sizeof(T);
return provider->ConsumeIntegralInRange<size_t>(0, max);
}
// Uses the given |provider| to generate several instances of T, store them in
// |data|, and then return a std::span to them. It is the caller's responsbility
// to ensure |data| remains in scope as long as the returned std::span.
template <typename T>
std::span<const T> ConsumeSpan(FuzzedDataProvider* provider,
std::vector<T>* data) {
size_t num = ConsumeSize<T>(provider);
size_t off = data->size();
data->reserve(off + num);
for (size_t i = 0; i < num; ++i) {
if constexpr (std::is_floating_point<T>::value) {
data->push_back(provider->ConsumeFloatingPoint<T>());
} else {
data->push_back(provider->ConsumeIntegral<T>());
}
}
return std::span(&((*data)[off]), num);
}
// Uses the given |provider| to generate a string, store it in |data|, and
// return a C-style representation. It is the caller's responsbility to
// ensure |data| remains in scope as long as the returned char*.
const char* ConsumeString(FuzzedDataProvider* provider,
std::vector<std::string>* data) {
size_t off = data->size();
// OSS-Fuzz's clang doesn't have the zero-parameter version of
// ConsumeRandomLengthString yet.
size_t max_length = std::numeric_limits<size_t>::max();
data->push_back(provider->ConsumeRandomLengthString(max_length));
return (*data)[off].c_str();
}
// Uses the given |provider| to generate non-arithmetic bytes, store them in
// |data|, and return a std::span to them. It is the caller's responsbility to
// ensure |data| remains in scope as long as the returned std::span.
std::span<const std::byte> ConsumeBytes(FuzzedDataProvider* provider,
std::vector<std::byte>* data) {
size_t num = ConsumeSize<std::byte>(provider);
auto added = provider->ConsumeBytes<std::byte>(num);
size_t off = data->size();
num = added.size();
data->insert(data->end(), added.begin(), added.end());
return std::span(&((*data)[off]), num);
}
} // namespace
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
static std::byte buffer[65536];
FuzzedDataProvider provider(data, size);
// Pick a subset of the buffer that the fuzzer is allowed to use, and poison
// the rest.
size_t unpoisoned_length =
provider.ConsumeIntegralInRange<size_t>(0, sizeof(buffer));
std::span<std::byte> unpoisoned(buffer, unpoisoned_length);
void* poisoned = &buffer[unpoisoned_length];
size_t poisoned_length = sizeof(buffer) - unpoisoned_length;
ASAN_POISON_MEMORY_REGION(poisoned, poisoned_length);
pw::protobuf::NestedEncoder encoder(unpoisoned);
// Storage for generated spans
std::vector<uint32_t> u32s;
std::vector<uint64_t> u64s;
std::vector<int32_t> s32s;
std::vector<int64_t> s64s;
std::vector<float> floats;
std::vector<double> doubles;
std::vector<std::string> strings;
std::vector<std::byte> bytes;
// Consume the fuzzing input, using it to generate a sequence of fields to
// encode. Both the uint32_t field IDs and the fields values are generated.
// Don't try to detect errors, ensures pushes and pops are balanced, or
// otherwise hold the interface correctly. Instead, fuzz the widest possbile
// set of inputs to the encoder to ensure it doesn't misbehave.
while (provider.remaining_bytes() != 0) {
switch (provider.ConsumeEnum<FieldType>()) {
case kEncodeAndClear:
// Special "field". Encode all the fields so far and reset the encoder.
encoder.Encode();
encoder.Clear();
break;
case kUint32:
encoder.WriteUint32(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<uint32_t>());
break;
case kPackedUint32:
encoder.WritePackedUint32(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<uint32_t>(&provider, &u32s));
break;
case kUint64:
encoder.WriteUint64(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<uint64_t>());
break;
case kPackedUint64:
encoder.WritePackedUint64(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<uint64_t>(&provider, &u64s));
break;
case kInt32:
encoder.WriteInt32(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int32_t>());
break;
case kPackedInt32:
encoder.WritePackedInt32(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int32_t>(&provider, &s32s));
break;
case kInt64:
encoder.WriteInt64(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int64_t>());
break;
case kPackedInt64:
encoder.WritePackedInt64(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int64_t>(&provider, &s64s));
break;
case kSint32:
encoder.WriteSint32(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int32_t>());
break;
case kPackedSint32:
encoder.WritePackedSint32(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int32_t>(&provider, &s32s));
break;
case kSint64:
encoder.WriteSint64(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int64_t>());
break;
case kPackedSint64:
encoder.WritePackedSint64(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int64_t>(&provider, &s64s));
break;
case kBool:
encoder.WriteBool(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeBool());
break;
case kFixed32:
encoder.WriteFixed32(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<uint32_t>());
break;
case kPackedFixed32:
encoder.WritePackedFixed32(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<uint32_t>(&provider, &u32s));
break;
case kFixed64:
encoder.WriteFixed64(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<uint64_t>());
break;
case kPackedFixed64:
encoder.WritePackedFixed64(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<uint64_t>(&provider, &u64s));
break;
case kSfixed32:
encoder.WriteSfixed32(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int32_t>());
break;
case kPackedSfixed32:
encoder.WritePackedSfixed32(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int32_t>(&provider, &s32s));
break;
case kSfixed64:
encoder.WriteSfixed64(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeIntegral<int64_t>());
break;
case kPackedSfixed64:
encoder.WritePackedSfixed64(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<int64_t>(&provider, &s64s));
break;
case kFloat:
encoder.WriteFloat(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeFloatingPoint<float>());
break;
case kPackedFloat:
encoder.WritePackedFloat(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<float>(&provider, &floats));
break;
case kDouble:
encoder.WriteDouble(provider.ConsumeIntegral<uint32_t>(),
provider.ConsumeFloatingPoint<double>());
break;
case kPackedDouble:
encoder.WritePackedDouble(provider.ConsumeIntegral<uint32_t>(),
ConsumeSpan<double>(&provider, &doubles));
break;
case kBytes:
encoder.WriteBytes(provider.ConsumeIntegral<uint32_t>(),
ConsumeBytes(&provider, &bytes));
break;
case kString:
encoder.WriteString(provider.ConsumeIntegral<uint32_t>(),
ConsumeString(&provider, &strings));
break;
case kPush:
// Special "field". The marks the start of a nested message.
encoder.Push(provider.ConsumeIntegral<uint32_t>());
break;
case kPop:
// Special "field". this marks the end of a nested message. No attempt
// is made to match pushes to pops, in order to test that the encoder
// behaves correctly when they are mismatched.
encoder.Pop();
break;
}
}
// Ensure we call `Encode` at least once.
encoder.Encode();
// Don't forget to unpoison for the next iteration!
ASAN_UNPOISON_MEMORY_REGION(poisoned, poisoned_length);
return 0;
}