def test_parse_simple_with_arg(self):
"""Allow simple denylist policy files."""
path = self._write_file(
'test.policy', """
# Comment.
@denylist
read: return ENOSYS
write: arg0 == 0 ; return ENOSYS
""")
self.assertEqual(
self.parser.parse_file(path),
parser.ParsedPolicy(
default_action=bpf.Allow(),
filter_statements=[
parser.FilterStatement(
syscall=parser.Syscall('read', 0),
frequency=1,
filters=[
parser.Filter(
None,
bpf.ReturnErrno(
self.arch.constants['ENOSYS'])),
]),
parser.FilterStatement(
syscall=parser.Syscall('write', 1),
frequency=1,
filters=[
parser.Filter([[parser.Atom(0, '==', 0)]],
bpf.ReturnErrno(
self.arch.constants['ENOSYS'])),
parser.Filter(None, bpf.Allow()),
]),
]))
def test_parse_filter(self):
"""Accept valid filters."""
self.assertEqual(
self.parser.parse_filter(self._tokenize('arg0 == 0')), [
parser.Filter([[parser.Atom(0, '==', 0)]], bpf.Allow()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('kill-process')), [
parser.Filter(None, bpf.KillProcess()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('kill-thread')), [
parser.Filter(None, bpf.KillThread()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('trap')), [
parser.Filter(None, bpf.Trap()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('return ENOSYS')), [
parser.Filter(None,
bpf.ReturnErrno(self.arch.constants['ENOSYS'])),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('trace')), [
parser.Filter(None, bpf.Trace()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('user-notify')), [
parser.Filter(None, bpf.UserNotify()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('log')), [
parser.Filter(None, bpf.Log()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('allow')), [
parser.Filter(None, bpf.Allow()),
])
self.assertEqual(
self.parser.parse_filter(self._tokenize('1')), [
parser.Filter(None, bpf.Allow()),
])
self.assertEqual(
self.parser.parse_filter(
self._tokenize(
'{ arg0 == 0, arg0 == 1; return ENOSYS, trap }')),
[
parser.Filter([[parser.Atom(0, '==', 0)]], bpf.Allow()),
parser.Filter([[parser.Atom(0, '==', 1)]],
bpf.ReturnErrno(self.arch.constants['ENOSYS'])),
parser.Filter(None, bpf.Trap()),
])
def parse_action(self, tokens):
if not tokens:
self._parser_state.error('missing action')
action_token = tokens.pop(0)
if action_token.type == 'ACTION':
if action_token.value == 'allow':
return bpf.Allow()
if action_token.value == 'kill':
return self._kill_action
if action_token.value == 'kill-process':
return bpf.KillProcess()
if action_token.value == 'kill-thread':
return bpf.KillThread()
if action_token.value == 'trap':
return bpf.Trap()
if action_token.value == 'trace':
return bpf.Trace()
if action_token.value == 'log':
return bpf.Log()
elif action_token.type == 'NUMERIC_CONSTANT':
constant = self._parse_single_constant(action_token)
if constant == 1:
return bpf.Allow()
elif action_token.type == 'RETURN':
if not tokens:
self._parser_state.error('missing return value')
return bpf.ReturnErrno(self._parse_single_constant(tokens.pop(0)))
return self._parser_state.error('invalid action', token=action_token)
def test_parse_filter(self):
"""Accept only filters that return an errno."""
self.assertEqual(
self.parser.parse_filter(
self._tokenize('arg0 == 0; return ENOSYS')),
[
parser.Filter([[parser.Atom(0, '==', 0)]],
bpf.ReturnErrno(self.arch.constants['ENOSYS'])),
])
def parse_action(self, tokens):
if not tokens:
self._parser_state.error('missing action')
action_token = tokens.pop(0)
# denylist policies must specify a return for every line.
if self._denylist:
if action_token.type != 'RETURN':
self._parser_state.error('invalid denylist policy')
if action_token.type == 'ACTION':
if action_token.value == 'allow':
return bpf.Allow()
if action_token.value == 'kill':
return self._kill_action
if action_token.value == 'kill-process':
return bpf.KillProcess()
if action_token.value == 'kill-thread':
return bpf.KillThread()
if action_token.value == 'trap':
return bpf.Trap()
if action_token.value == 'trace':
return bpf.Trace()
if action_token.value == 'user-notify':
return bpf.UserNotify()
if action_token.value == 'log':
return bpf.Log()
elif action_token.type == 'NUMERIC_CONSTANT':
constant = self._parse_single_constant(action_token)
if constant == 1:
return bpf.Allow()
elif action_token.type == 'RETURN':
if not tokens:
self._parser_state.error('missing return value')
if self._ret_log:
tokens.pop(0)
return bpf.Log()
else:
return bpf.ReturnErrno(
self._parse_single_constant(tokens.pop(0)))
return self._parser_state.error('invalid action', token=action_token)
def test_parse_include(self):
"""Allow including policy files."""
path = self._write_file(
'test.include.policy', """
{read, write}: arg0 == 0; allow
""")
path = self._write_file(
'test.policy', """
@include ./test.include.policy
read: return ENOSYS
""")
self.assertEqual(
self.parser.parse_file(path),
parser.ParsedPolicy(
default_action=bpf.KillProcess(),
filter_statements=[
parser.FilterStatement(
syscall=parser.Syscall('read', 0),
frequency=1,
filters=[
parser.Filter([[parser.Atom(0, '==', 0)]],
bpf.Allow()),
parser.Filter(
None,
bpf.ReturnErrno(
self.arch.constants['ENOSYS'])),
]),
parser.FilterStatement(
syscall=parser.Syscall('write', 1),
frequency=1,
filters=[
parser.Filter([[parser.Atom(0, '==', 0)]],
bpf.Allow()),
parser.Filter(None, bpf.KillProcess()),
]),
]))
def main(argv=None):
"""Main entrypoint."""
if argv is None:
argv = sys.argv[1:]
opts, arg_parser = parse_args(argv)
if not os.path.exists(opts.arch_json):
arg_parser.error(CONSTANTS_ERR_MSG)
parsed_arch = arch.Arch.load_from_json(opts.arch_json)
policy_compiler = compiler.PolicyCompiler(parsed_arch)
# Set ret_log to true if the MINIJAIL_DEFAULT_RET_LOG environment variable
# is present.
if 'MINIJAIL_DEFAULT_RET_LOG' in os.environ:
print("""
\n**********************
Warning: MINJAIL_DEFAULT_RET_LOG is on, policy will not have any effect
**********************\n
""")
opts.use_ret_log = True
if opts.use_ret_log:
kill_action = bpf.Log()
elif opts.denylist:
# Default action for a denylist policy is return EPERM
kill_action = bpf.ReturnErrno(parsed_arch.constants['EPERM'])
elif opts.use_kill_process:
kill_action = bpf.KillProcess()
else:
kill_action = bpf.KillThread()
override_default_action = None
if opts.default_action:
parser_state = parser.ParserState('<memory>')
override_default_action = parser.PolicyParser(
parsed_arch, kill_action=bpf.KillProcess()).parse_action(
next(parser_state.tokenize([opts.default_action])))
compiled_policy = policy_compiler.compile_file(
opts.policy.name,
optimization_strategy=opts.optimization_strategy,
kill_action=kill_action,
include_depth_limit=opts.include_depth_limit,
override_default_action=override_default_action,
denylist=opts.denylist,
ret_log=opts.use_ret_log)
# Outputs the bpf binary to a c header file instead of a binary file.
if opts.output_header_file:
output_file_base = opts.output
with open(output_file_base + '.h', 'w') as output_file:
program = ', '.join('%i' % x for x in compiled_policy.opcodes)
output_file.write(
HEADER_TEMPLATE % {
'upper_name': output_file_base.upper(),
'name': output_file_base,
'program': program,
})
else:
with open(opts.output, 'wb') as outf:
outf.write(compiled_policy.opcodes)
return 0
