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.
Raises:
TimeoutError: If the cleanse exceeds max_time.
"""
runner = libfuzzer.get_runner(target_path)
libfuzzer.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)
if result.timed_out:
logs.log_error('Cleanse timed out.', fuzzer_output=result.output)
raise TimeoutError('Cleanse timed out.')
return engine.ReproduceResult(result.command, result.return_code,
result.time_executed, result.output)
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.
Raises:
TimeoutError: If the reproduction exceeds max_time.
"""
runner = libfuzzer.get_runner(target_path)
libfuzzer.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[:]
libfuzzer.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)
if result.timed_out:
raise TimeoutError('Reproducing 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:
logs.log_error('Merging new testcases timed out.',
fuzzer_output=result.output)
raise TimeoutError('Merging new testcases timed out.')
if result.return_code != 0:
logs.log_error('Merging new testcases timed out.',
fuzzer_output=result.output)
raise MergeError('Merging new testcases failed.')
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 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, fuzz_options=options)
# Directory to place new units.
if options.merge_back_new_testcases:
new_corpus_dir = self._create_temp_corpus_dir('new')
corpus_directories = [new_corpus_dir] + options.fuzz_corpus_dirs
else:
corpus_directories = options.fuzz_corpus_dirs
fuzz_result = runner.fuzz(corpus_directories,
fuzz_timeout=max_time,
additional_args=options.arguments,
artifact_prefix=reproducers_dir,
extra_env=options.extra_env)
project_qualified_fuzzer_name = (
engine_common.get_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 '
f'(target={project_qualified_fuzzer_name}, '
f'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 +
f' (target={project_qualified_fuzzer_name}).',
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 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
not in constants.NONCRASH_RETURN_CODES):
crash_testcase_file_path = self._create_empty_testcase_file(
reproducers_dir)
# 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)
actual_duration = int(fuzz_result.time_executed)
fuzzing_time_percent = 100 * actual_duration / float(max_time)
parsed_stats.update({
'timeout_limit': int(timeout_limit),
'expected_duration': int(max_time),
'actual_duration': actual_duration,
'fuzzing_time_percent': fuzzing_time_percent,
})
# Remove fuzzing arguments before merge and dictionary analysis step.
non_fuzz_arguments = options.arguments.copy()
libfuzzer.remove_fuzzing_arguments(non_fuzz_arguments, is_merge=True)
if options.merge_back_new_testcases:
self._merge_new_units(target_path, options.corpus_dir,
new_corpus_dir, options.fuzz_corpus_dirs,
non_fuzz_arguments, parsed_stats)
fuzz_logs = '\n'.join(log_lines)
crashes = []
if crash_testcase_file_path:
reproduce_arguments = options.arguments[:]
libfuzzer.remove_fuzzing_arguments(reproduce_arguments)
# Use higher timeout for reproduction.
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))
if options.analyze_dictionary:
libfuzzer.analyze_and_update_recommended_dictionary(
runner, project_qualified_fuzzer_name, log_lines,
options.corpus_dir, non_fuzz_arguments)
return engine.FuzzResult(fuzz_logs, fuzz_result.command, crashes,
parsed_stats, fuzz_result.time_executed)