src/test_lib_json/fuzz.cpp

// Copyright 2007-2019 The JsonCpp Authors
// Distributed under MIT license, or public domain if desired and
// recognized in your jurisdiction.
// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE

#include "fuzz.h"

#include <cstdint>
#include <json/config.h>
#include <json/json.h>
#include <memory>
#include <string>

namespace Json {
class Exception;
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
  Json::CharReaderBuilder builder;

  if (size < sizeof(uint32_t)) {
    return 0;
  }

  const uint32_t hash_settings = static_cast<uint32_t>(data[0]) |
                                 (static_cast<uint32_t>(data[1]) << 8) |
                                 (static_cast<uint32_t>(data[2]) << 16) |
                                 (static_cast<uint32_t>(data[3]) << 24);
  data += sizeof(uint32_t);
  size -= sizeof(uint32_t);

  builder.settings_["failIfExtra"] = hash_settings & (1 << 0);
  builder.settings_["allowComments_"] = hash_settings & (1 << 1);
  builder.settings_["strictRoot_"] = hash_settings & (1 << 2);
  builder.settings_["allowDroppedNullPlaceholders_"] = hash_settings & (1 << 3);
  builder.settings_["allowNumericKeys_"] = hash_settings & (1 << 4);
  builder.settings_["allowSingleQuotes_"] = hash_settings & (1 << 5);
  builder.settings_["failIfExtra_"] = hash_settings & (1 << 6);
  builder.settings_["rejectDupKeys_"] = hash_settings & (1 << 7);
  builder.settings_["allowSpecialFloats_"] = hash_settings & (1 << 8);
  builder.settings_["collectComments"] = hash_settings & (1 << 9);
  builder.settings_["allowTrailingCommas_"] = hash_settings & (1 << 10);

  std::unique_ptr<Json::CharReader> reader(builder.newCharReader());

  Json::Value root;
  const auto data_str = reinterpret_cast<const char*>(data);
  try {
    reader->parse(data_str, data_str + size, &root, nullptr);
  } catch (Json::Exception const&) {
  }
  // Whether it succeeded or not doesn't matter.
  return 0;
}