def use_mutator_plugin(target_name, extra_env, chroot):
"""Decide whether to use a mutator plugin. If yes and there is a usable plugin
available for |target_name|, then add it to LD_PRELOAD in |extra_env|, add
chroot bindings if |chroot| is not None, and return True."""
# TODO(metzman): Support Windows.
if environment.platform() == 'WINDOWS':
return False
mutator_plugin_path = mutator_plugin.get_mutator_plugin(target_name)
if not mutator_plugin_path:
return False
logs.log('Using mutator plugin: %s' % mutator_plugin_path)
# TODO(metzman): Change the strategy to record which plugin was used, and
# not simply that a plugin was used.
extra_env['LD_PRELOAD'] = mutator_plugin_path
if chroot:
mutator_plugin_dir = os.path.dirname(mutator_plugin_path)
chroot.add_binding(
minijail.ChrootBinding(mutator_plugin_dir, mutator_plugin_dir,
False))
return True
def test_minijail_bindings(self):
"""Test minijail process command with additional bind dirs."""
with minijail.MinijailChroot(bindings=[
minijail.ChrootBinding('/foo/bar', '/bar', True),
minijail.ChrootBinding('/foo/barr', '/barr', False),
]) as chroot:
runner = minijail.MinijailProcessRunner(chroot, '/bin/ls')
self.assertListEqual(runner.get_command(), [
'/sbin/minijail', '-U', '-m', '0 1000 1', '-T', 'static', '-c',
'0', '-n', '-v', '-p', '-l', '-I', '-k', 'proc,/proc,proc,1',
'-P', chroot.directory, '-b',
'%s,/tmp,1' % chroot.tmp_directory, '-b', '/lib,/lib,0', '-b',
'/lib32,/lib32,0', '-b', '/lib64,/lib64,0', '-b',
'/usr/lib,/usr/lib,0', '-b', '/foo/bar,/bar,1', '-b',
'/foo/barr,/barr,0', '/bin/ls'
])
def get_runner(fuzzer_path, temp_dir=None):
"""Get a libfuzzer runner."""
use_minijail = environment.get_value('USE_MINIJAIL')
build_dir = environment.get_value('BUILD_DIR')
if use_minijail:
# Set up chroot and runner.
if environment.is_chromeos_system_job():
minijail_chroot = minijail.ChromeOSChroot(build_dir)
else:
minijail_chroot = minijail.MinijailChroot(base_dir=temp_dir)
# While it's possible for dynamic binaries to run without this, they need
# to be accessible for symbolization etc. For simplicity we bind BUILD_DIR
# to the same location within the chroot, which leaks the directory
# structure of CF but this shouldn't be a big deal.
minijail_chroot.add_binding(
minijail.ChrootBinding(build_dir, build_dir, False))
# Also bind the build dir to /out to make it easier to hardcode references
# to data files.
minijail_chroot.add_binding(
minijail.ChrootBinding(build_dir, '/out', False))
minijail_bin = os.path.join(minijail_chroot.directory, 'bin')
shell.create_directory(minijail_bin)
# Set up /bin with llvm-symbolizer to allow symbolized stacktraces.
# Don't copy if it already exists (e.g. ChromeOS chroot jail).
llvm_symbolizer_source_path = environment.get_llvm_symbolizer_path()
llvm_symbolizer_destination_path = os.path.join(minijail_bin,
'llvm-symbolizer')
if not os.path.exists(llvm_symbolizer_destination_path):
shutil.copy(llvm_symbolizer_source_path, llvm_symbolizer_destination_path)
# copy /bin/sh, necessary for system().
if not environment.is_chromeos_system_job():
# The chroot has its own shell we don't need to copy (and probably
# shouldn't because of library differences).
shutil.copy(os.path.realpath('/bin/sh'), os.path.join(minijail_bin, 'sh'))
runner = MinijailLibFuzzerRunner(fuzzer_path, minijail_chroot)
elif environment.platform() == 'FUCHSIA':
runner = FuchsiaQemuLibFuzzerRunner(fuzzer_path)
else:
runner = LibFuzzerRunner(fuzzer_path)
return runner
def unbind_corpus_dirs(chroot, corpus_directories):
"""Unbind corpus directories from the minijail chroot.
Args:
chroot: The MinijailChroot.
corpus_directories: A list of corpus paths.
"""
for corpus_directory in corpus_directories:
target_dir = '/' + os.path.basename(corpus_directory)
chroot.remove_binding(
minijail.ChrootBinding(corpus_directory, target_dir, True))
def test_chroot(self):
"""Tests basic chroot setup."""
chroot_directory = None
with minijail.MinijailChroot() as chroot:
chroot_directory = chroot.directory
self.assertListEqual(
sorted(os.listdir(chroot_directory)),
['dev', 'lib', 'lib32', 'lib64', 'proc', 'tmp', 'usr'])
self.assertEqual(
chroot.get_binding(chroot.tmp_directory),
minijail.ChrootBinding(chroot.tmp_directory, '/tmp', True))
for directory in ['/lib', '/lib32', '/lib64', '/usr/lib']:
self.assertEqual(
chroot.get_binding(directory),
minijail.ChrootBinding(directory, directory, False))
self.assertIsNone(chroot.get_binding('/usr'))
self.assertFalse(os.path.exists(chroot_directory))
def _bind_corpus_dirs(self, corpus_directories):
"""Bind corpus directories to the minijail chroot.
Also makes sure that the directories are world writeable.
Args:
corpus_directories: A list of corpus paths.
"""
for corpus_directory in corpus_directories:
target_dir = '/' + os.path.basename(corpus_directory)
self.chroot.add_binding(
minijail.ChrootBinding(corpus_directory, target_dir, writeable=True))
