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# Copyright 2021 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.
"""Module for interacting with the "ClusterFuzz deployment."""
import logging
import os
import sys
import tempfile
import time
import urllib.error
import urllib.request
import zipfile
# pylint: disable=wrong-import-position,import-error
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
import utils
class BaseClusterFuzzDeployment:
"""Base class for ClusterFuzz deployments."""
CORPUS_DIR_NAME = 'cifuzz-corpus'
BUILD_DIR_NAME = 'cifuzz-latest-build'
def __init__(self, config):
self.config = config
def download_latest_build(self, out_dir):
"""Downloads the latest build from ClusterFuzz.
Returns:
A path to where the OSS-Fuzz build was stored, or None if it wasn't.
"""
raise NotImplementedError('Child class must implement method.')
def download_corpus(self, target_name, out_dir):
"""Downloads the corpus for |target_name| from ClusterFuzz to |out_dir|.
Returns:
A path to where the OSS-Fuzz build was stored, or None if it wasn't.
"""
raise NotImplementedError('Child class must implement method.')
class ClusterFuzzLite(BaseClusterFuzzDeployment):
"""Class representing a deployment of ClusterFuzzLite."""
def download_latest_build(self, out_dir):
logging.info('download_latest_build not implemented for ClusterFuzzLite.')
def download_corpus(self, target_name, out_dir):
logging.info('download_corpus not implemented for ClusterFuzzLite.')
class OSSFuzz(BaseClusterFuzzDeployment):
"""The OSS-Fuzz ClusterFuzz deployment."""
# Location of clusterfuzz builds on GCS.
CLUSTERFUZZ_BUILDS = 'clusterfuzz-builds'
# Format string for the latest version of a project's build.
VERSION_STRING = '{project_name}-{sanitizer}-latest.version'
# Zip file name containing the corpus.
CORPUS_ZIP_NAME = 'public.zip'
def get_latest_build_name(self):
"""Gets the name of the latest OSS-Fuzz build of a project.
Returns:
A string with the latest build version or None.
"""
version_file = self.VERSION_STRING.format(
project_name=self.config.project_name, sanitizer=self.config.sanitizer)
version_url = utils.url_join(utils.GCS_BASE_URL, self.CLUSTERFUZZ_BUILDS,
self.config.project_name, version_file)
try:
response = urllib.request.urlopen(version_url)
except urllib.error.HTTPError:
logging.error('Error getting latest build version for %s from: %s.',
self.config.project_name, version_url)
return None
return response.read().decode()
def download_latest_build(self, out_dir):
"""Downloads the latest OSS-Fuzz build from GCS.
Returns:
A path to where the OSS-Fuzz build was stored, or None if it wasn't.
"""
build_dir = os.path.join(out_dir, self.BUILD_DIR_NAME)
if os.path.exists(build_dir):
return build_dir
os.makedirs(build_dir, exist_ok=True)
latest_build_name = self.get_latest_build_name()
if not latest_build_name:
return None
oss_fuzz_build_url = utils.url_join(utils.GCS_BASE_URL,
self.CLUSTERFUZZ_BUILDS,
self.config.project_name,
latest_build_name)
if download_and_unpack_zip(oss_fuzz_build_url, build_dir):
return build_dir
return None
def download_corpus(self, target_name, out_dir):
"""Downloads the latest OSS-Fuzz corpus for the target.
Returns:
The local path to to corpus or None if download failed.
"""
corpus_dir = os.path.join(out_dir, self.CORPUS_DIR_NAME, target_name)
os.makedirs(corpus_dir, exist_ok=True)
# TODO(metzman): Clean up this code.
project_qualified_fuzz_target_name = target_name
qualified_name_prefix = self.config.project_name + '_'
if not target_name.startswith(qualified_name_prefix):
project_qualified_fuzz_target_name = qualified_name_prefix + target_name
corpus_url = utils.url_join(
utils.GCS_BASE_URL,
'{0}-backup.clusterfuzz-external.appspot.com/corpus/libFuzzer/'.format(
self.config.project_name), project_qualified_fuzz_target_name,
self.CORPUS_ZIP_NAME)
if download_and_unpack_zip(corpus_url, corpus_dir):
return corpus_dir
return None
def download_url(url, filename, num_attempts=3):
"""Downloads the file located at |url|, using HTTP to |filename|.
Args:
url: A url to a file to download.
filename: The path the file should be downloaded to.
num_retries: The number of times to retry the download on
ConnectionResetError.
Returns:
True on success.
"""
sleep_time = 1
# Don't use retry wrapper since we don't want this to raise any exceptions.
for _ in range(num_attempts):
try:
urllib.request.urlretrieve(url, filename)
return True
except urllib.error.HTTPError:
# In these cases, retrying probably wont work since the error probably
# means there is nothing at the URL to download.
logging.error('Unable to download from: %s.', url)
return False
except ConnectionResetError:
# These errors are more likely to be transient. Retry.
pass
time.sleep(sleep_time)
logging.error('Failed to download %s, %d times.', url, num_attempts)
return False
def download_and_unpack_zip(url, extract_directory):
"""Downloads and unpacks a zip file from an HTTP URL.
Args:
url: A url to the zip file to be downloaded and unpacked.
out_dir: The path where the zip file should be extracted to.
Returns:
True on success.
"""
if not os.path.exists(extract_directory):
logging.error('Extract directory: %s does not exist.', extract_directory)
return False
# Gives the temporary zip file a unique identifier in the case that
# that download_and_unpack_zip is done in parallel.
with tempfile.NamedTemporaryFile(suffix='.zip') as tmp_file:
if not download_url(url, tmp_file.name):
return False
try:
with zipfile.ZipFile(tmp_file.name, 'r') as zip_file:
zip_file.extractall(extract_directory)
except zipfile.BadZipFile:
logging.error('Error unpacking zip from %s. Bad Zipfile.', url)
return False
return True
def get_clusterfuzz_deployment(config):
"""Returns object reprsenting deployment of ClusterFuzz used by |config|."""
if (config.platform == config.Platform.INTERNAL_GENERIC_CI or
config.platform == config.Platform.INTERNAL_GITHUB):
logging.info('Using OSS-Fuzz as ClusterFuzz deployment.')
return OSSFuzz(config)
logging.info('Using ClusterFuzzLite as ClusterFuzz deployment.')
return ClusterFuzzLite(config)
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