mirror of https://github.com/google/oss-fuzz.git
412 lines
13 KiB
Python
412 lines
13 KiB
Python
# Copyright 2019 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Module to build a image from a specific commit, branch or pull request
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This module is allows each of the OSS Fuzz projects fuzzers to be built
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from a specific point in time. This feature can be used for implementations
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like continuious integration fuzzing and bisection to find errors
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"""
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import argparse
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import bisect
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import datetime
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from distutils import spawn
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import os
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import collections
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import json
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import logging
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import re
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import shutil
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import tempfile
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import helper
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import repo_manager
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import retry
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import utils
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BuildData = collections.namedtuple(
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'BuildData', ['project_name', 'engine', 'sanitizer', 'architecture'])
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_GIT_DIR_MARKER = 'gitdir: '
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_IMAGE_BUILD_TRIES = 3
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class BaseBuilderRepo:
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"""Repo of base-builder images."""
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def __init__(self):
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self.timestamps = []
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self.digests = []
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def add_digest(self, timestamp, digest):
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"""Add a digest."""
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self.timestamps.append(timestamp)
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self.digests.append(digest)
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def find_digest(self, timestamp):
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"""Find the latest image before the given timestamp."""
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index = bisect.bisect_right(self.timestamps, timestamp)
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if index > 0:
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return self.digests[index - 1]
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logging.error('Failed to find suitable base-builder.')
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return None
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def _replace_gitdir(src_dir, file_path):
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"""Replace gitdir with a relative path."""
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with open(file_path) as handle:
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lines = handle.readlines()
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new_lines = []
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for line in lines:
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if line.startswith(_GIT_DIR_MARKER):
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absolute_path = line[len(_GIT_DIR_MARKER):].strip()
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if not os.path.isabs(absolute_path):
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# Already relative.
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return
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current_dir = os.path.dirname(file_path)
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# Rebase to /src rather than the host src dir.
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base_dir = current_dir.replace(src_dir, '/src')
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relative_path = os.path.relpath(absolute_path, base_dir)
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logging.info('Replacing absolute submodule gitdir from %s to %s',
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absolute_path, relative_path)
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line = _GIT_DIR_MARKER + relative_path
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new_lines.append(line)
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with open(file_path, 'w') as handle:
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handle.write(''.join(new_lines))
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def _make_gitdirs_relative(src_dir):
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"""Make gitdirs relative."""
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for root_dir, _, files in os.walk(src_dir):
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for filename in files:
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if filename != '.git':
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continue
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file_path = os.path.join(root_dir, filename)
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_replace_gitdir(src_dir, file_path)
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def _replace_base_builder_digest(dockerfile_path, digest):
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"""Replace the base-builder digest in a Dockerfile."""
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with open(dockerfile_path) as handle:
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lines = handle.readlines()
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new_lines = []
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for line in lines:
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if line.strip().startswith('FROM'):
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line = 'FROM gcr.io/oss-fuzz-base/base-builder@' + digest + '\n'
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new_lines.append(line)
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with open(dockerfile_path, 'w') as handle:
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handle.write(''.join(new_lines))
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def copy_src_from_docker(project_name, host_dir):
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"""Copy /src from docker to the host."""
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# Copy /src to host.
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image_name = 'gcr.io/oss-fuzz/' + project_name
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src_dir = os.path.join(host_dir, 'src')
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if os.path.exists(src_dir):
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shutil.rmtree(src_dir, ignore_errors=True)
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docker_args = [
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'-v',
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host_dir + ':/out',
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image_name,
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'cp',
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'-r',
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'-p',
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'/src',
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'/out',
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]
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helper.docker_run(docker_args)
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# Submodules can have gitdir entries which point to absolute paths. Make them
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# relative, as otherwise we can't do operations on the checkout on the host.
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_make_gitdirs_relative(src_dir)
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return src_dir
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@retry.wrap(_IMAGE_BUILD_TRIES, 2)
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def _build_image_with_retries(project_name):
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"""Build image with retries."""
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return helper.build_image_impl(project_name)
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def get_required_post_checkout_steps(dockerfile_path):
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"""Get required post checkout steps (best effort)."""
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checkout_pattern = re.compile(r'\s*RUN\s*(git|svn|hg)')
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# If the build.sh is copied from upstream, we need to copy it again after
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# changing the revision to ensure correct building.
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post_run_pattern = re.compile(r'\s*RUN\s*(.*build\.sh.*(\$SRC|/src).*)')
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with open(dockerfile_path) as handle:
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lines = handle.readlines()
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subsequent_run_cmds = []
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for i, line in enumerate(lines):
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if checkout_pattern.match(line):
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subsequent_run_cmds = []
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continue
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match = post_run_pattern.match(line)
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if match:
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workdir = helper.workdir_from_lines(lines[:i])
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command = match.group(1)
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subsequent_run_cmds.append((workdir, command))
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return subsequent_run_cmds
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# pylint: disable=too-many-locals
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def build_fuzzers_from_commit(commit,
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build_repo_manager,
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host_src_path,
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build_data,
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base_builder_repo=None):
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"""Builds a OSS-Fuzz fuzzer at a specific commit SHA.
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Args:
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commit: The commit SHA to build the fuzzers at.
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build_repo_manager: The OSS-Fuzz project's repo manager to be built at.
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build_data: A struct containing project build information.
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base_builder_repo: A BaseBuilderRepo.
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Returns:
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0 on successful build or error code on failure.
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"""
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oss_fuzz_repo_manager = repo_manager.RepoManager(helper.OSS_FUZZ_DIR)
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num_retry = 1
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def cleanup():
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# Re-copy /src for a clean checkout every time.
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copy_src_from_docker(build_data.project_name,
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os.path.dirname(host_src_path))
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build_repo_manager.fetch_all_remotes()
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projects_dir = os.path.join('projects', build_data.project_name)
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dockerfile_path = os.path.join(projects_dir, 'Dockerfile')
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for i in range(num_retry + 1):
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build_repo_manager.checkout_commit(commit, clean=False)
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post_checkout_steps = get_required_post_checkout_steps(dockerfile_path)
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for workdir, post_checkout_step in post_checkout_steps:
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logging.info('Running post-checkout step `%s` in %s.', post_checkout_step,
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workdir)
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helper.docker_run([
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'-w',
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workdir,
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'-v',
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host_src_path + ':' + '/src',
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'gcr.io/oss-fuzz/' + build_data.project_name,
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'/bin/bash',
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'-c',
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post_checkout_step,
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])
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result = helper.build_fuzzers_impl(project_name=build_data.project_name,
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clean=True,
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engine=build_data.engine,
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sanitizer=build_data.sanitizer,
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architecture=build_data.architecture,
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env_to_add=None,
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source_path=host_src_path,
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mount_path='/src')
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if result or i == num_retry:
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break
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# Retry with an OSS-Fuzz builder container that's closer to the project
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# commit date.
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commit_date = build_repo_manager.commit_date(commit)
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# Find first change in the projects/<PROJECT> directory before the project
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# commit date.
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oss_fuzz_commit, _, _ = oss_fuzz_repo_manager.git([
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'log', '--before=' + commit_date.isoformat(), '-n1', '--format=%H',
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projects_dir
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],
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check_result=True)
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oss_fuzz_commit = oss_fuzz_commit.strip()
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if not oss_fuzz_commit:
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logging.info(
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'Could not find first OSS-Fuzz commit prior to upstream commit. '
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'Falling back to oldest integration commit.')
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# Find the oldest commit.
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oss_fuzz_commit, _, _ = oss_fuzz_repo_manager.git(
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['log', '--reverse', '--format=%H', projects_dir], check_result=True)
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oss_fuzz_commit = oss_fuzz_commit.splitlines()[0].strip()
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if not oss_fuzz_commit:
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logging.error('Failed to get oldest integration commit.')
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break
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logging.info('Build failed. Retrying on earlier OSS-Fuzz commit %s.',
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oss_fuzz_commit)
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# Check out projects/<PROJECT> dir to the commit that was found.
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oss_fuzz_repo_manager.git(['checkout', oss_fuzz_commit, projects_dir],
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check_result=True)
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# Also use the closest base-builder we can find.
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if base_builder_repo:
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base_builder_digest = base_builder_repo.find_digest(commit_date)
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if not base_builder_digest:
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return False
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logging.info('Using base-builder with digest %s.', base_builder_digest)
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_replace_base_builder_digest(dockerfile_path, base_builder_digest)
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# Rebuild image and re-copy src dir since things in /src could have changed.
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if not _build_image_with_retries(build_data.project_name):
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logging.error('Failed to rebuild image.')
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return False
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cleanup()
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cleanup()
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return result
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def detect_main_repo(project_name, repo_name=None, commit=None):
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"""Checks a docker image for the main repo of an OSS-Fuzz project.
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Note: The default is to use the repo name to detect the main repo.
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Args:
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project_name: The name of the oss-fuzz project.
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repo_name: The name of the main repo in an OSS-Fuzz project.
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commit: A commit SHA that is associated with the main repo.
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src_dir: The location of the projects source on the docker image.
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Returns:
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The repo's origin, the repo's path.
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"""
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if not repo_name and not commit:
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logging.error(
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'Error: can not detect main repo without a repo_name or a commit.')
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return None, None
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if repo_name and commit:
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logging.info(
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'Both repo name and commit specific. Using repo name for detection.')
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# Change to oss-fuzz main directory so helper.py runs correctly.
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utils.chdir_to_root()
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if not _build_image_with_retries(project_name):
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logging.error('Error: building %s image failed.', project_name)
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return None, None
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docker_image_name = 'gcr.io/oss-fuzz/' + project_name
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command_to_run = [
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'docker', 'run', '--rm', '-t', docker_image_name, 'python3',
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os.path.join('/opt', 'cifuzz', 'detect_repo.py')
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]
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if repo_name:
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command_to_run.extend(['--repo_name', repo_name])
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else:
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command_to_run.extend(['--example_commit', commit])
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out, _, _ = utils.execute(command_to_run)
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match = re.search(r'\bDetected repo: ([^ ]+) ([^ ]+)', out.rstrip())
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if match and match.group(1) and match.group(2):
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return match.group(1), match.group(2)
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logging.error('Failed to detect repo:\n%s', out)
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return None, None
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def load_base_builder_repo():
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"""Get base-image digests."""
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gcloud_path = spawn.find_executable('gcloud')
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if not gcloud_path:
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logging.warning('gcloud not found in PATH.')
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return None
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result, _, _ = utils.execute([
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gcloud_path,
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'container',
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'images',
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'list-tags',
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'gcr.io/oss-fuzz-base/base-builder',
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'--format=json',
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'--sort-by=timestamp',
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],
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check_result=True)
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result = json.loads(result)
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repo = BaseBuilderRepo()
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for image in result:
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timestamp = datetime.datetime.fromisoformat(
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image['timestamp']['datetime']).astimezone(datetime.timezone.utc)
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repo.add_digest(timestamp, image['digest'])
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return repo
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def main():
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"""Main function."""
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logging.getLogger().setLevel(logging.INFO)
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parser = argparse.ArgumentParser(
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description='Build fuzzers at a specific commit')
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parser.add_argument('--project_name',
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help='The name of the project where the bug occurred.',
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required=True)
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parser.add_argument('--commit',
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help='The newest commit SHA to be bisected.',
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required=True)
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parser.add_argument('--engine',
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help='The default is "libfuzzer".',
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default='libfuzzer')
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parser.add_argument('--sanitizer',
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default='address',
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help='The default is "address".')
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parser.add_argument('--architecture', default='x86_64')
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args = parser.parse_args()
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repo_url, repo_path = detect_main_repo(args.project_name, commit=args.commit)
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if not repo_url or not repo_path:
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raise ValueError('Main git repo can not be determined.')
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with tempfile.TemporaryDirectory() as tmp_dir:
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host_src_dir = copy_src_from_docker(args.project_name, tmp_dir)
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build_repo_manager = repo_manager.RepoManager(
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os.path.join(host_src_dir, os.path.basename(repo_path)))
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base_builder_repo = load_base_builder_repo()
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build_data = BuildData(project_name=args.project_name,
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engine=args.engine,
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sanitizer=args.sanitizer,
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architecture=args.architecture)
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if not build_fuzzers_from_commit(args.commit,
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build_repo_manager,
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host_src_dir,
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build_data,
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base_builder_repo=base_builder_repo):
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raise RuntimeError('Failed to build.')
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if __name__ == '__main__':
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main()
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