oss-fuzz/projects/bad_example/bad_example_fuzzer.cc

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/* Copyright 2022 Google LLC
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 <stddef.h>
#include <stdint.h>
#include <string.h>

#include <signal.h>
#include <unistd.h>

#include "zlib.h"

static Bytef buffer[256 * 1024] = { 0 };


#ifdef INTENTIONAL_STARTUP_CRASH
void bad_term_handler(int signum) {
  _exit(0);
}
#endif

// Entry point for LibFuzzer.
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
#ifdef INTENTIONAL_STARTUP_CRASH
  // Simulates the worst case, fuzz target silently dies without any error.
  struct sigaction action = { 0 };
  action.sa_handler = bad_term_handler;
  sigaction(SIGTERM, &action, NULL);

  // Cannot call _exit(0) directly, as it's even worse -- sancov does not print
  // any coverage information in that case.
  kill(getpid(), SIGTERM);
#endif

  uLongf buffer_length = static_cast<uLongf>(sizeof(buffer));
  if (Z_OK != uncompress(buffer, &buffer_length, data,
                         static_cast<uLong>(size))) {
    return 0;
  }
  return 0;
}