def cleanse(self, target_path, arguments, input_path, output_path, max_time): """Optional (but recommended): Cleanse a testcase. Args: target_path: Path to the target. arguments: Additional arguments needed for testcase cleanse. input_path: Path to the reproducer input. output_path: Path to the cleansed output. max_time: Maximum allowed time for the cleanse. Returns: A boolean indicating success. """ runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) cleanse_tmp_dir = self._create_temp_corpus_dir('cleanse-workdir') artifact_prefix = self._artifact_prefix(cleanse_tmp_dir) result = runner.cleanse_crash(input_path, output_path, max_time, additional_args=arguments + [artifact_prefix]) return result.return_code == 0
def reproduce(self, target_path, input_path, arguments, max_time): """Reproduce a crash given an input. Args: target_path: Path to the target. input_path: Path to the reproducer input. arguments: Additional arguments needed for reproduction. max_time: Maximum allowed time for the reproduction. Returns: A ReproduceResult. """ runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) # Remove fuzzing specific arguments. This is only really needed for legacy # testcases, and can be removed in the distant future. arguments = arguments[:] launcher.remove_fuzzing_arguments(arguments) runs_argument = constants.RUNS_FLAG + str(constants.RUNS_TO_REPRODUCE) arguments.append(runs_argument) result = runner.run_single_testcase( input_path, timeout=max_time, additional_args=arguments) return engine.ReproduceResult(result.command, result.return_code, result.time_executed, result.output)
def __init__(self, build_directory, context): self.build_directory = build_directory self.context = context self.fuzzer_path = engine_common.find_fuzzer_path( self.build_directory, self.context.fuzz_target.binary) if not self.fuzzer_path: raise CorpusPruningException('Failed to get fuzzer path for %s.' % self.context.fuzz_target.binary) fuzz_inputs_disk = environment.get_value('FUZZ_INPUTS_DISK') self.runner = libfuzzer.get_runner(self.fuzzer_path, temp_dir=fuzz_inputs_disk) if context.use_minijail: self.runner.chroot.add_binding( minijail.ChrootBinding(self.context.initial_corpus_path, '/corpus', False)) self.runner.chroot.add_binding( minijail.ChrootBinding(self.context.minimized_corpus_path, '/min', True)) self.runner.chroot.add_binding( minijail.ChrootBinding(self.context.shared_corpus_path, '/shared', False)) self.runner.chroot.add_binding( minijail.ChrootBinding(self.context.bad_units_path, '/bad_units', True)) self.fuzzer_options = options.get_fuzz_target_options(self.fuzzer_path)
def cleanse(self, target_path, arguments, input_path, output_path, max_time): """Optional (but recommended): Cleanse a testcase. Args: target_path: Path to the target. arguments: Additional arguments needed for testcase cleanse. input_path: Path to the reproducer input. output_path: Path to the cleansed output. max_time: Maximum allowed time for the cleanse. Returns: A ReproduceResult. """ runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) cleanse_tmp_dir = self._create_temp_corpus_dir('cleanse-workdir') result = runner.cleanse_crash( input_path, output_path, max_time, artifact_prefix=cleanse_tmp_dir, additional_args=arguments) return engine.ReproduceResult(result.command, result.return_code, result.time_executed, result.output)
def minimize_corpus(self, target_path, arguments, input_dirs, output_dir, reproducers_dir, max_time): """Optional (but recommended): run corpus minimization. Args: target_path: Path to the target. arguments: Additional arguments needed for corpus minimization. input_dirs: Input corpora. output_dir: Output directory to place minimized corpus. reproducers_dir: The directory to put reproducers in when crashes are found. max_time: Maximum allowed time for the minimization. Returns: A Result object. """ runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) merge_tmp_dir = self._create_temp_corpus_dir('merge-workdir') merge_result = runner.merge([output_dir] + input_dirs, merge_timeout=max_time, tmp_dir=merge_tmp_dir, additional_args=arguments, artifact_prefix=reproducers_dir) if merge_result.timed_out: raise MergeError('Merging new testcases timed out') if merge_result.return_code != 0: raise MergeError('Merging new testcases failed') # TODO(ochang): Get crashes found during merge. return engine.FuzzResult(merge_result.output, merge_result.command, [], {}, merge_result.time_executed)
def minimize_testcase(self, target_path, arguments, input_path, output_path, max_time): """Optional (but recommended): Minimize a testcase. Args: target_path: Path to the target. arguments: Additional arguments needed for testcase minimization. input_path: Path to the reproducer input. output_path: Path to the minimized output. max_time: Maximum allowed time for the minimization. Returns: A ReproduceResult. Raises: TimeoutError: If the testcase minimization exceeds max_time. """ runner = libfuzzer.get_runner(target_path) libfuzzer.set_sanitizer_options(target_path) minimize_tmp_dir = self._create_temp_corpus_dir('minimize-workdir') result = runner.minimize_crash(input_path, output_path, max_time, artifact_prefix=minimize_tmp_dir, additional_args=arguments) if result.timed_out: raise TimeoutError('Minimization timed out\n' + result.output) return engine.ReproduceResult(result.command, result.return_code, result.time_executed, result.output)
def minimize_corpus(self, target_path, arguments, input_dirs, output_dir, reproducers_dir, max_time): """Optional (but recommended): run corpus minimization. Args: target_path: Path to the target. arguments: Additional arguments needed for corpus minimization. input_dirs: Input corpora. output_dir: Output directory to place minimized corpus. reproducers_dir: The directory to put reproducers in when crashes are found. max_time: Maximum allowed time for the minimization. Returns: A Result object. Raises: TimeoutError: If the corpus minimization exceeds max_time. Error: If the merge failed in some other way. """ runner = libfuzzer.get_runner(target_path) libfuzzer.set_sanitizer_options(target_path) merge_tmp_dir = self._create_temp_corpus_dir('merge-workdir') result = runner.merge([output_dir] + input_dirs, merge_timeout=max_time, tmp_dir=merge_tmp_dir, additional_args=arguments, artifact_prefix=reproducers_dir, merge_control_file=getattr( self, '_merge_control_file', None)) if result.timed_out: raise TimeoutError('Merging new testcases timed out\n' + result.output) if result.return_code != 0: raise MergeError('Merging new testcases failed: ' + result.output) merge_output = result.output merge_stats = stats.parse_stats_from_merge_log( merge_output.splitlines()) # TODO(ochang): Get crashes found during merge. return engine.FuzzResult(merge_output, result.command, [], merge_stats, result.time_executed)
def reproduce(self, target_path, input_path, arguments, max_time): """Reproduce a crash given an input. Args: target_path: Path to the target. input_path: Path to the reproducer input. arguments: Additional arguments needed for reproduction. max_time: Maximum allowed time for the reproduction. Returns: A ReproduceResult. """ runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) result = runner.run_single_testcase(input_path, timeout=max_time, additional_args=arguments) return engine.ReproduceResult(result.return_code, result.time_executed, result.output)
def main(argv): """Run libFuzzer as specified by argv.""" atexit.register(fuzzer_utils.cleanup) # Initialize variables. arguments = argv[1:] testcase_file_path = arguments.pop(0) target_name = arguments.pop(0) fuzzer_name = data_types.fuzz_target_project_qualified_name( utils.current_project(), target_name) # Initialize log handler. logs.configure( 'run_fuzzer', { 'fuzzer': fuzzer_name, 'engine': 'libFuzzer', 'job_name': environment.get_value('JOB_NAME') }) profiler.start_if_needed('libfuzzer_launcher') # Make sure that the fuzzer binary exists. build_directory = environment.get_value('BUILD_DIR') fuzzer_path = engine_common.find_fuzzer_path(build_directory, target_name) if not fuzzer_path: # This is an expected case when doing regression testing with old builds # that do not have that fuzz target. It can also happen when a host sends a # message to an untrusted worker that just restarted and lost information on # build directory. logs.log_warn('Could not find fuzz target %s.' % target_name) return # Install signal handler. signal.signal(signal.SIGTERM, engine_common.signal_term_handler) # Set up temp dir. engine_common.recreate_directory(fuzzer_utils.get_temp_dir()) # Setup minijail if needed. use_minijail = environment.get_value('USE_MINIJAIL') runner = libfuzzer.get_runner(fuzzer_path, temp_dir=fuzzer_utils.get_temp_dir()) if use_minijail: minijail_chroot = runner.chroot else: minijail_chroot = None # Get corpus directory. corpus_directory = environment.get_value('FUZZ_CORPUS_DIR') # Add common arguments which are necessary to be used for every run. arguments = expand_with_common_arguments(arguments) # Add sanitizer options to environment that were specified in the .options # file and options that this script requires. set_sanitizer_options(fuzzer_path) # Minimize test argument. minimize_to = fuzzer_utils.extract_argument(arguments, MINIMIZE_TO_ARGUMENT) minimize_timeout = fuzzer_utils.extract_argument( arguments, MINIMIZE_TIMEOUT_ARGUMENT) if minimize_to and minimize_timeout: minimize_testcase(runner, testcase_file_path, minimize_to, int(minimize_timeout), arguments, use_minijail) return # Cleanse argument. cleanse_to = fuzzer_utils.extract_argument(arguments, CLEANSE_TO_ARGUMENT) cleanse_timeout = fuzzer_utils.extract_argument(arguments, CLEANSE_TIMEOUT_ARGUMENT) if cleanse_to and cleanse_timeout: cleanse_testcase(runner, testcase_file_path, cleanse_to, int(cleanse_timeout), arguments, use_minijail) return # If we don't have a corpus, then that means this is not a fuzzing run. if not corpus_directory: load_testcase_if_exists(runner, testcase_file_path, fuzzer_name, use_minijail, arguments) return # We don't have a crash testcase, fuzz. # Check dict argument to make sure that it's valid. dict_argument = fuzzer_utils.extract_argument(arguments, constants.DICT_FLAG, remove=False) if dict_argument and not os.path.exists(dict_argument): logs.log_error('Invalid dict %s for %s.' % (dict_argument, fuzzer_name)) fuzzer_utils.extract_argument(arguments, constants.DICT_FLAG) # If there's no dict argument, check for %target_binary_name%.dict file. if (not fuzzer_utils.extract_argument( arguments, constants.DICT_FLAG, remove=False)): default_dict_path = dictionary_manager.get_default_dictionary_path( fuzzer_path) if os.path.exists(default_dict_path): arguments.append(constants.DICT_FLAG + default_dict_path) fuzzing_strategies = [] # Select a generator to use for existing testcase mutations. generator = _select_generator() is_mutations_run = generator != Generator.NONE # Timeout for fuzzer run. fuzz_timeout = get_fuzz_timeout(is_mutations_run) # Set up scratch directory for writing new units. new_testcases_directory = create_corpus_directory('new') # Get list of corpus directories. corpus_directories = get_corpus_directories(corpus_directory, new_testcases_directory, fuzzer_path, fuzzing_strategies, minijail_chroot) # Bind corpus directories in minijail. if use_minijail: artifact_prefix = constants.ARTIFACT_PREFIX_FLAG + '/' else: artifact_prefix = '%s%s/' % (constants.ARTIFACT_PREFIX_FLAG, os.path.abspath( os.path.dirname(testcase_file_path))) # Generate new testcase mutations using radamsa, etc. if is_mutations_run: new_testcase_mutations_directory = generate_new_testcase_mutations( corpus_directory, fuzzer_name, generator, fuzzing_strategies) corpus_directories.append(new_testcase_mutations_directory) if use_minijail: bind_corpus_dirs(minijail_chroot, [new_testcase_mutations_directory]) max_len_argument = fuzzer_utils.extract_argument(arguments, constants.MAX_LEN_FLAG, remove=False) if not max_len_argument and do_random_max_length(): max_length = random.SystemRandom().randint(1, MAX_VALUE_FOR_MAX_LENGTH) arguments.append('%s%d' % (constants.MAX_LEN_FLAG, max_length)) fuzzing_strategies.append(strategy.RANDOM_MAX_LENGTH_STRATEGY) if do_recommended_dictionary(): if add_recommended_dictionary(arguments, fuzzer_name, fuzzer_path): fuzzing_strategies.append(strategy.RECOMMENDED_DICTIONARY_STRATEGY) if do_value_profile(): arguments.append(constants.VALUE_PROFILE_ARGUMENT) fuzzing_strategies.append(strategy.VALUE_PROFILE_STRATEGY) if do_fork(): max_fuzz_threads = environment.get_value('MAX_FUZZ_THREADS', 1) num_fuzz_processes = max( 1, multiprocessing.cpu_count() // max_fuzz_threads) arguments.append('%s%d' % (constants.FORK_FLAG, num_fuzz_processes)) fuzzing_strategies.append('%s_%d' % (strategy.FORK_STRATEGY, num_fuzz_processes)) extra_env = {} if do_mutator_plugin(): if use_mutator_plugin(target_name, extra_env, minijail_chroot): fuzzing_strategies.append(strategy.MUTATOR_PLUGIN_STRATEGY) # Execute the fuzzer binary with original arguments. fuzz_result = runner.fuzz(corpus_directories, fuzz_timeout=fuzz_timeout, additional_args=arguments + [artifact_prefix], extra_env=extra_env) if (not use_minijail and fuzz_result.return_code == constants.LIBFUZZER_ERROR_EXITCODE): # Minijail returns 1 if the exit code is nonzero. # Otherwise: we can assume that a return code of 1 means that libFuzzer # itself ran into an error. logs.log_error(ENGINE_ERROR_MESSAGE, engine_output=fuzz_result.output) log_lines = fuzz_result.output.splitlines() # Output can be large, so save some memory by removing reference to the # original output which is no longer needed. fuzz_result.output = None # Check if we crashed, and get the crash testcase path. crash_testcase_file_path = None for line in log_lines: match = re.match(CRASH_TESTCASE_REGEX, line) if match: crash_testcase_file_path = match.group(1) break if crash_testcase_file_path: # Write the new testcase. if use_minijail: # Convert chroot relative path to host path. Remove the leading '/' before # joining. crash_testcase_file_path = os.path.join( minijail_chroot.directory, crash_testcase_file_path[1:]) # Copy crash testcase contents into the main testcase path. shutil.move(crash_testcase_file_path, testcase_file_path) # Print the command output. log_header_format = ('Command: %s\n' 'Bot: %s\n' 'Time ran: %f\n') bot_name = environment.get_value('BOT_NAME', '') command = fuzz_result.command if use_minijail: # Remove minijail prefix. command = engine_common.strip_minijail_command(command, fuzzer_path) print(log_header_format % (engine_common.get_command_quoted(command), bot_name, fuzz_result.time_executed)) # Parse stats information based on libFuzzer output. parsed_stats = parse_log_stats(log_lines) # Extend parsed stats by additional performance features. parsed_stats.update( stats.parse_performance_features(log_lines, fuzzing_strategies, arguments)) # Set some initial stat overrides. timeout_limit = fuzzer_utils.extract_argument(arguments, constants.TIMEOUT_FLAG, remove=False) expected_duration = runner.get_max_total_time(fuzz_timeout) actual_duration = int(fuzz_result.time_executed) fuzzing_time_percent = 100 * actual_duration / float(expected_duration) stat_overrides = { 'timeout_limit': int(timeout_limit), 'expected_duration': expected_duration, 'actual_duration': actual_duration, 'fuzzing_time_percent': fuzzing_time_percent, } # Remove fuzzing arguments before merge and dictionary analysis step. remove_fuzzing_arguments(arguments) # Make a decision on whether merge step is needed at all. If there are no # new units added by libFuzzer run, then no need to do merge at all. new_units_added = shell.get_directory_file_count(new_testcases_directory) merge_error = None if new_units_added: # Merge the new units with the initial corpus. if corpus_directory not in corpus_directories: corpus_directories.append(corpus_directory) # If this times out, it's possible that we will miss some units. However, if # we're taking >10 minutes to load/merge the corpus something is going very # wrong and we probably don't want to make things worse by adding units # anyway. merge_tmp_dir = None if not use_minijail: merge_tmp_dir = os.path.join(fuzzer_utils.get_temp_dir(), 'merge_workdir') engine_common.recreate_directory(merge_tmp_dir) old_corpus_len = shell.get_directory_file_count(corpus_directory) merge_directory = create_merge_directory() corpus_directories.insert(0, merge_directory) if use_minijail: bind_corpus_dirs(minijail_chroot, [merge_directory]) merge_result = runner.merge( corpus_directories, merge_timeout=engine_common.get_merge_timeout( DEFAULT_MERGE_TIMEOUT), tmp_dir=merge_tmp_dir, additional_args=arguments) move_mergeable_units(merge_directory, corpus_directory) new_corpus_len = shell.get_directory_file_count(corpus_directory) new_units_added = 0 merge_error = None if merge_result.timed_out: merge_error = 'Merging new testcases timed out:' elif merge_result.return_code != 0: merge_error = 'Merging new testcases failed:' else: new_units_added = new_corpus_len - old_corpus_len stat_overrides['new_units_added'] = new_units_added if merge_result.output: stat_overrides.update( stats.parse_stats_from_merge_log( merge_result.output.splitlines())) else: stat_overrides['new_units_added'] = 0 logs.log('Skipped corpus merge since no new units added by fuzzing.') # Get corpus size after merge. This removes the duplicate units that were # created during this fuzzing session. stat_overrides['corpus_size'] = shell.get_directory_file_count( corpus_directory) # Delete all corpus directories except for the main one. These were temporary # directories to store new testcase mutations and have already been merged to # main corpus directory. if corpus_directory in corpus_directories: corpus_directories.remove(corpus_directory) for directory in corpus_directories: shutil.rmtree(directory, ignore_errors=True) if use_minijail: unbind_corpus_dirs(minijail_chroot, corpus_directories) # Apply overridden stats to the parsed stats prior to dumping. parsed_stats.update(stat_overrides) # Dump stats data for further uploading to BigQuery. engine_common.dump_big_query_data(parsed_stats, testcase_file_path, LIBFUZZER_PREFIX, fuzzer_name, command) # Add custom crash state based on fuzzer name (if needed). add_custom_crash_state_if_needed(fuzzer_name, log_lines, parsed_stats) for line in log_lines: print(line) # Add fuzzing strategies used. engine_common.print_fuzzing_strategies(fuzzing_strategies) # Add merge error (if any). if merge_error: print(data_types.CRASH_STACKTRACE_END_MARKER) print(merge_error) print( 'Command:', get_printable_command(merge_result.command, fuzzer_path, use_minijail)) print(merge_result.output) analyze_and_update_recommended_dictionary(runner, fuzzer_name, log_lines, corpus_directory, arguments) # Close minijail chroot. if use_minijail: minijail_chroot.close() # Record the stats to make them easily searchable in stackdriver. if new_units_added: logs.log('New units added to corpus: %d.' % new_units_added, stats=parsed_stats) else: logs.log('No new units found.', stats=parsed_stats)
def fuzz(self, target_path, options, reproducers_dir, max_time): """Run a fuzz session. Args: target_path: Path to the target. options: The FuzzOptions object returned by prepare(). reproducers_dir: The directory to put reproducers in when crashes are found. max_time: Maximum allowed time for the fuzzing to run. Returns: A Result object. """ profiler.start_if_needed('libfuzzer_fuzz') runner = libfuzzer.get_runner(target_path) launcher.set_sanitizer_options(target_path) artifact_prefix = self._artifact_prefix( os.path.abspath(reproducers_dir)) # Directory to place new units. new_corpus_dir = self._create_temp_corpus_dir('new') corpus_directories = [new_corpus_dir] + options.fuzz_corpus_dirs fuzz_timeout = launcher.get_fuzz_timeout(options.is_mutations_run, total_timeout=max_time) fuzz_result = runner.fuzz(corpus_directories, fuzz_timeout=fuzz_timeout, additional_args=options.arguments + [artifact_prefix], extra_env=options.extra_env) log_lines = fuzz_result.output.splitlines() # Output can be large, so save some memory by removing reference to the # original output which is no longer needed. fuzz_result.output = None # Check if we crashed, and get the crash testcase path. crash_testcase_file_path = None for line in log_lines: match = re.match(launcher.CRASH_TESTCASE_REGEX, line) if match: crash_testcase_file_path = match.group(1) break # Parse stats information based on libFuzzer output. parsed_stats = launcher.parse_log_stats(log_lines) # Extend parsed stats by additional performance features. parsed_stats.update( stats.parse_performance_features(log_lines, options.strategies, options.arguments, include_strategies=False)) # Set some initial stat overrides. timeout_limit = fuzzer_utils.extract_argument(options.arguments, constants.TIMEOUT_FLAG, remove=False) expected_duration = runner.get_max_total_time(fuzz_timeout) actual_duration = int(fuzz_result.time_executed) fuzzing_time_percent = 100 * actual_duration / float(expected_duration) parsed_stats.update({ 'timeout_limit': int(timeout_limit), 'expected_duration': expected_duration, 'actual_duration': actual_duration, 'fuzzing_time_percent': fuzzing_time_percent, }) # Remove fuzzing arguments before merge and dictionary analysis step. arguments = options.arguments[:] launcher.remove_fuzzing_arguments(arguments) self._merge_new_units(target_path, options.corpus_dir, new_corpus_dir, options.fuzz_corpus_dirs, arguments, parsed_stats) # Add custom crash state based on fuzzer name (if needed). project_qualified_fuzzer_name = ( data_types.fuzz_target_project_qualified_name( utils.current_project(), os.path.basename(target_path))) launcher.add_custom_crash_state_if_needed( project_qualified_fuzzer_name, log_lines, parsed_stats) fuzz_logs = '\n'.join(log_lines) crashes = [] if crash_testcase_file_path: # Write the new testcase. # Copy crash testcase contents into the main testcase path. crashes.append( engine.Crash(crash_testcase_file_path, fuzz_logs, arguments, actual_duration)) launcher.analyze_and_update_recommended_dictionary( runner, project_qualified_fuzzer_name, log_lines, options.corpus_dir, arguments) return engine.Result(fuzz_logs, fuzz_result.command, crashes, parsed_stats, fuzz_result.time_executed)
def main(argv): """Run libFuzzer as specified by argv.""" atexit.register(fuzzer_utils.cleanup) # Initialize variables. arguments = argv[1:] testcase_file_path = arguments.pop(0) target_name = environment.get_value('FUZZ_TARGET') if arguments and arguments[0] == target_name: # Pop legacy fuzz target argument. arguments.pop(0) fuzzer_name = data_types.fuzz_target_project_qualified_name( utils.current_project(), target_name) # Initialize log handler. logs.configure( 'run_fuzzer', { 'fuzzer': fuzzer_name, 'engine': 'libFuzzer', 'job_name': environment.get_value('JOB_NAME') }) profiler.start_if_needed('libfuzzer_launcher') # Make sure that the fuzzer binary exists. build_directory = environment.get_value('BUILD_DIR') fuzzer_path = engine_common.find_fuzzer_path(build_directory, target_name) if not fuzzer_path: return # Install signal handler. signal.signal(signal.SIGTERM, engine_common.signal_term_handler) # Set up temp dir. engine_common.recreate_directory(fuzzer_utils.get_temp_dir()) # Setup minijail if needed. use_minijail = environment.get_value('USE_MINIJAIL') runner = libfuzzer.get_runner( fuzzer_path, temp_dir=fuzzer_utils.get_temp_dir()) if use_minijail: minijail_chroot = runner.chroot else: minijail_chroot = None # Get corpus directory. corpus_directory = environment.get_value('FUZZ_CORPUS_DIR') # Add common arguments which are necessary to be used for every run. arguments = expand_with_common_arguments(arguments) # Add sanitizer options to environment that were specified in the .options # file and options that this script requires. set_sanitizer_options(fuzzer_path) # If we don't have a corpus, then that means this is not a fuzzing run. if not corpus_directory: load_testcase_if_exists(runner, testcase_file_path, fuzzer_name, use_minijail, arguments) return # We don't have a crash testcase, fuzz. # Check dict argument to make sure that it's valid. dict_argument = fuzzer_utils.extract_argument( arguments, constants.DICT_FLAG, remove=False) if dict_argument and not os.path.exists(dict_argument): logs.log_error('Invalid dict %s for %s.' % (dict_argument, fuzzer_name)) fuzzer_utils.extract_argument(arguments, constants.DICT_FLAG) # If there's no dict argument, check for %target_binary_name%.dict file. if (not fuzzer_utils.extract_argument( arguments, constants.DICT_FLAG, remove=False)): default_dict_path = dictionary_manager.get_default_dictionary_path( fuzzer_path) if os.path.exists(default_dict_path): arguments.append(constants.DICT_FLAG + default_dict_path) # Set up scratch directory for writing new units. new_testcases_directory = create_corpus_directory('new') # Strategy pool is the list of strategies that we attempt to enable, whereas # fuzzing strategies is the list of strategies that are enabled. (e.g. if # mutator is selected in the pool, but not available for a given target, it # would not be added to fuzzing strategies.) strategy_pool = strategy_selection.generate_weighted_strategy_pool( strategy_list=strategy.LIBFUZZER_STRATEGY_LIST, use_generator=True, engine_name='libFuzzer') strategy_info = pick_strategies( strategy_pool, fuzzer_path, corpus_directory, arguments, minijail_chroot=minijail_chroot) arguments.extend(strategy_info.arguments) # Timeout for fuzzer run. fuzz_timeout = get_fuzz_timeout(strategy_info.is_mutations_run) # Get list of corpus directories. # TODO(flowerhack): Implement this to handle corpus sync'ing. if environment.platform() == 'FUCHSIA': corpus_directories = [] else: corpus_directories = get_corpus_directories( corpus_directory, new_testcases_directory, fuzzer_path, strategy_info.fuzzing_strategies, strategy_pool, minijail_chroot=minijail_chroot, allow_corpus_subset=not strategy_info.use_dataflow_tracing) corpus_directories.extend(strategy_info.additional_corpus_dirs) artifact_prefix = os.path.abspath(os.path.dirname(testcase_file_path)) # Execute the fuzzer binary with original arguments. fuzz_result = runner.fuzz( corpus_directories, fuzz_timeout=fuzz_timeout, artifact_prefix=artifact_prefix, additional_args=arguments, extra_env=strategy_info.extra_env) if (not use_minijail and fuzz_result.return_code == constants.LIBFUZZER_ERROR_EXITCODE): # Minijail returns 1 if the exit code is nonzero. # Otherwise: we can assume that a return code of 1 means that libFuzzer # itself ran into an error. logs.log_error(ENGINE_ERROR_MESSAGE, engine_output=fuzz_result.output) log_lines = fuzz_result.output.splitlines() # Output can be large, so save some memory by removing reference to the # original output which is no longer needed. fuzz_result.output = None # Check if we crashed, and get the crash testcase path. crash_testcase_file_path = runner.get_testcase_path(log_lines) if crash_testcase_file_path: # Copy crash testcase contents into the main testcase path. shutil.move(crash_testcase_file_path, testcase_file_path) # Print the command output. bot_name = environment.get_value('BOT_NAME', '') command = fuzz_result.command if use_minijail: # Remove minijail prefix. command = engine_common.strip_minijail_command(command, fuzzer_path) print(engine_common.get_log_header(command, bot_name, fuzz_result.time_executed)) # Parse stats information based on libFuzzer output. parsed_stats = parse_log_stats(log_lines) # Extend parsed stats by additional performance features. parsed_stats.update( stats.parse_performance_features( log_lines, strategy_info.fuzzing_strategies, arguments)) # Set some initial stat overrides. timeout_limit = fuzzer_utils.extract_argument( arguments, constants.TIMEOUT_FLAG, remove=False) expected_duration = runner.get_max_total_time(fuzz_timeout) actual_duration = int(fuzz_result.time_executed) fuzzing_time_percent = 100 * actual_duration / float(expected_duration) stat_overrides = { 'timeout_limit': int(timeout_limit), 'expected_duration': expected_duration, 'actual_duration': actual_duration, 'fuzzing_time_percent': fuzzing_time_percent, } # Remove fuzzing arguments before merge and dictionary analysis step. remove_fuzzing_arguments(arguments) # Make a decision on whether merge step is needed at all. If there are no # new units added by libFuzzer run, then no need to do merge at all. new_units_added = shell.get_directory_file_count(new_testcases_directory) merge_error = None if new_units_added: # Merge the new units with the initial corpus. if corpus_directory not in corpus_directories: corpus_directories.append(corpus_directory) # If this times out, it's possible that we will miss some units. However, if # we're taking >10 minutes to load/merge the corpus something is going very # wrong and we probably don't want to make things worse by adding units # anyway. merge_tmp_dir = None if not use_minijail: merge_tmp_dir = os.path.join(fuzzer_utils.get_temp_dir(), 'merge_workdir') engine_common.recreate_directory(merge_tmp_dir) old_corpus_len = shell.get_directory_file_count(corpus_directory) merge_directory = create_merge_directory() corpus_directories.insert(0, merge_directory) if use_minijail: bind_corpus_dirs(minijail_chroot, [merge_directory]) merge_result = runner.merge( corpus_directories, merge_timeout=engine_common.get_merge_timeout(DEFAULT_MERGE_TIMEOUT), tmp_dir=merge_tmp_dir, additional_args=arguments) move_mergeable_units(merge_directory, corpus_directory) new_corpus_len = shell.get_directory_file_count(corpus_directory) new_units_added = 0 merge_error = None if merge_result.timed_out: merge_error = 'Merging new testcases timed out:' elif merge_result.return_code != 0: merge_error = 'Merging new testcases failed:' else: new_units_added = new_corpus_len - old_corpus_len stat_overrides['new_units_added'] = new_units_added if merge_result.output: stat_overrides.update( stats.parse_stats_from_merge_log(merge_result.output.splitlines())) else: stat_overrides['new_units_added'] = 0 logs.log('Skipped corpus merge since no new units added by fuzzing.') # Get corpus size after merge. This removes the duplicate units that were # created during this fuzzing session. # TODO(flowerhack): Remove this workaround once we can handle corpus sync. if environment.platform() != 'FUCHSIA': stat_overrides['corpus_size'] = shell.get_directory_file_count( corpus_directory) # Delete all corpus directories except for the main one. These were temporary # directories to store new testcase mutations and have already been merged to # main corpus directory. if corpus_directory in corpus_directories: corpus_directories.remove(corpus_directory) for directory in corpus_directories: shutil.rmtree(directory, ignore_errors=True) if use_minijail: unbind_corpus_dirs(minijail_chroot, corpus_directories) # Apply overridden stats to the parsed stats prior to dumping. parsed_stats.update(stat_overrides) # Dump stats data for further uploading to BigQuery. engine_common.dump_big_query_data(parsed_stats, testcase_file_path, command) # Add custom crash state based on fuzzer name (if needed). add_custom_crash_state_if_needed(fuzzer_name, log_lines, parsed_stats) for line in log_lines: print(line) # Add fuzzing strategies used. print(engine_common.format_fuzzing_strategies( strategy_info.fuzzing_strategies)) # Add merge error (if any). if merge_error: print(data_types.CRASH_STACKTRACE_END_MARKER) print(merge_error) print('Command:', get_printable_command(merge_result.command, fuzzer_path, use_minijail)) print(merge_result.output) analyze_and_update_recommended_dictionary(runner, fuzzer_name, log_lines, corpus_directory, arguments) # Close minijail chroot. if use_minijail: minijail_chroot.close() # Record the stats to make them easily searchable in stackdriver. if new_units_added: logs.log( 'New units added to corpus: %d.' % new_units_added, stats=parsed_stats) else: logs.log('No new units found.', stats=parsed_stats)
def fuzz(self, target_path, options, reproducers_dir, max_time): """Run a fuzz session. Args: target_path: Path to the target. options: The FuzzOptions object returned by prepare(). reproducers_dir: The directory to put reproducers in when crashes are found. max_time: Maximum allowed time for the fuzzing to run. Returns: A FuzzResult object. """ profiler.start_if_needed('libfuzzer_fuzz') runner = libfuzzer.get_runner(target_path) libfuzzer.set_sanitizer_options(target_path) # Directory to place new units. new_corpus_dir = self._create_temp_corpus_dir('new') corpus_directories = [new_corpus_dir] + options.fuzz_corpus_dirs fuzz_timeout = libfuzzer.get_fuzz_timeout(options.is_mutations_run, total_timeout=max_time) fuzz_result = runner.fuzz(corpus_directories, fuzz_timeout=fuzz_timeout, additional_args=options.arguments, artifact_prefix=reproducers_dir, extra_env=options.extra_env) if (not environment.get_value('USE_MINIJAIL') and fuzz_result.return_code == constants.LIBFUZZER_ERROR_EXITCODE): # Minijail returns 1 if the exit code is nonzero. # Otherwise: we can assume that a return code of 1 means that libFuzzer # itself ran into an error. logs.log_error(ENGINE_ERROR_MESSAGE, engine_output=fuzz_result.output) log_lines = utils.decode_to_unicode(fuzz_result.output).splitlines() # Output can be large, so save some memory by removing reference to the # original output which is no longer needed. fuzz_result.output = None # Check if we crashed, and get the crash testcase path. crash_testcase_file_path = runner.get_testcase_path(log_lines) # Parse stats information based on libFuzzer output. parsed_stats = libfuzzer.parse_log_stats(log_lines) # Extend parsed stats by additional performance features. parsed_stats.update( stats.parse_performance_features(log_lines, options.strategies, options.arguments, include_strategies=False)) # Set some initial stat overrides. timeout_limit = fuzzer_utils.extract_argument(options.arguments, constants.TIMEOUT_FLAG, remove=False) expected_duration = runner.get_max_total_time(fuzz_timeout) actual_duration = int(fuzz_result.time_executed) fuzzing_time_percent = 100 * actual_duration / float(expected_duration) parsed_stats.update({ 'timeout_limit': int(timeout_limit), 'expected_duration': expected_duration, 'actual_duration': actual_duration, 'fuzzing_time_percent': fuzzing_time_percent, }) # Remove fuzzing arguments before merge and dictionary analysis step. arguments = options.arguments[:] libfuzzer.remove_fuzzing_arguments(arguments) self._merge_new_units(target_path, options.corpus_dir, new_corpus_dir, options.fuzz_corpus_dirs, arguments, parsed_stats) fuzz_logs = '\n'.join(log_lines) crashes = [] if crash_testcase_file_path: # Use higher timeout for reproduction. reproduce_arguments = arguments[:] libfuzzer.fix_timeout_argument_for_reproduction( reproduce_arguments) # Write the new testcase. # Copy crash testcase contents into the main testcase path. crashes.append( engine.Crash(crash_testcase_file_path, fuzz_logs, reproduce_arguments, actual_duration)) project_qualified_fuzzer_name = ( data_types.fuzz_target_project_qualified_name( utils.current_project(), os.path.basename(target_path))) libfuzzer.analyze_and_update_recommended_dictionary( runner, project_qualified_fuzzer_name, log_lines, options.corpus_dir, arguments) return engine.FuzzResult(fuzz_logs, fuzz_result.command, crashes, parsed_stats, fuzz_result.time_executed)
def fuzz(self, target_path, options, reproducers_dir, max_time): """Run a fuzz session. Args: target_path: Path to the target. options: The FuzzOptions object returned by prepare(). reproducers_dir: The directory to put reproducers in when crashes are found. max_time: Maximum allowed time for the fuzzing to run. Returns: A FuzzResult object. """ profiler.start_if_needed("libfuzzer_fuzz") runner = libfuzzer.get_runner(target_path) libfuzzer.set_sanitizer_options(target_path) # Directory to place new units. new_corpus_dir = self._create_temp_corpus_dir("new") corpus_directories = [new_corpus_dir] + options.fuzz_corpus_dirs fuzz_timeout = libfuzzer.get_fuzz_timeout(options.is_mutations_run, total_timeout=max_time) fuzz_result = runner.fuzz( corpus_directories, fuzz_timeout=fuzz_timeout, additional_args=options.arguments, artifact_prefix=reproducers_dir, extra_env=options.extra_env, ) project_qualified_fuzzer_name = _project_qualified_fuzzer_name( target_path) dict_error_match = DICT_PARSING_FAILED_REGEX.search(fuzz_result.output) if dict_error_match: logs.log_error( "Dictionary parsing failed (target={target}, line={line}).". format(target=project_qualified_fuzzer_name, line=dict_error_match.group(1)), engine_output=fuzz_result.output, ) elif (not environment.get_value("USE_MINIJAIL") and fuzz_result.return_code == constants.LIBFUZZER_ERROR_EXITCODE): # Minijail returns 1 if the exit code is nonzero. # Otherwise: we can assume that a return code of 1 means that libFuzzer # itself ran into an error. logs.log_error( ENGINE_ERROR_MESSAGE + " (target={target}).".format( target=project_qualified_fuzzer_name), engine_output=fuzz_result.output, ) log_lines = utils.decode_to_unicode(fuzz_result.output).splitlines() # Output can be large, so save some memory by removing reference to the # original output which is no longer needed. fuzz_result.output = None # Check if we crashed, and get the crash testcase path. crash_testcase_file_path = runner.get_testcase_path(log_lines) # If we exited with a non-zero return code with no crash file in output from # libFuzzer, this is most likely a startup crash. Use an empty testcase to # to store it as a crash. if not crash_testcase_file_path and fuzz_result.return_code: crash_testcase_file_path = self._create_empty_testcase_file() # Parse stats information based on libFuzzer output. parsed_stats = libfuzzer.parse_log_stats(log_lines) # Extend parsed stats by additional performance features. parsed_stats.update( stats.parse_performance_features(log_lines, options.strategies, options.arguments)) # Set some initial stat overrides. timeout_limit = fuzzer_utils.extract_argument(options.arguments, constants.TIMEOUT_FLAG, remove=False) expected_duration = runner.get_max_total_time(fuzz_timeout) actual_duration = int(fuzz_result.time_executed) fuzzing_time_percent = 100 * actual_duration / float(expected_duration) parsed_stats.update({ "timeout_limit": int(timeout_limit), "expected_duration": expected_duration, "actual_duration": actual_duration, "fuzzing_time_percent": fuzzing_time_percent, }) # Remove fuzzing arguments before merge and dictionary analysis step. arguments = options.arguments[:] libfuzzer.remove_fuzzing_arguments(arguments) self._merge_new_units( target_path, options.corpus_dir, new_corpus_dir, options.fuzz_corpus_dirs, arguments, parsed_stats, ) fuzz_logs = "\n".join(log_lines) crashes = [] if crash_testcase_file_path: # Use higher timeout for reproduction. reproduce_arguments = arguments[:] libfuzzer.fix_timeout_argument_for_reproduction( reproduce_arguments) # Write the new testcase. # Copy crash testcase contents into the main testcase path. crashes.append( engine.Crash( crash_testcase_file_path, fuzz_logs, reproduce_arguments, actual_duration, )) libfuzzer.analyze_and_update_recommended_dictionary( runner, project_qualified_fuzzer_name, log_lines, options.corpus_dir, arguments, ) return engine.FuzzResult( fuzz_logs, fuzz_result.command, crashes, parsed_stats, fuzz_result.time_executed, )