scripts/cros_fuzz_unittest.py

# Copyright 2018 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Unit tests for cros_fuzz."""

import logging
import os

from chromite.lib import cros_test_lib
from chromite.scripts import cros_fuzz


DEFAULT_MAX_TOTAL_TIME_OPTION = cros_fuzz.GetLibFuzzerOption(
    cros_fuzz.MAX_TOTAL_TIME_OPTION_NAME, cros_fuzz.MAX_TOTAL_TIME_DEFAULT_VALUE
)

FUZZ_TARGET = "fuzzer"
FUZZER_COVERAGE_PATH = (
    "/build/amd64-generic/tmp/fuzz/coverage-report/%s" % FUZZ_TARGET
)

BOARD = "amd64-generic"


class SysrootPathTest(cros_test_lib.TestCase):
    """Tests the SysrootPath class."""

    def setUp(self):
        self.path_to_sysroot = _SetPathToSysroot()
        self.sysroot_relative_path = "/dir"
        self.basename = os.path.basename(self.sysroot_relative_path)
        # Chroot relative path of a path that is in the sysroot.
        self.path_in_sysroot = os.path.join(self.path_to_sysroot, self.basename)

    def testSysroot(self):
        """Tests that SysrootPath.sysroot returns expected result."""
        sysroot_path = cros_fuzz.SysrootPath(self.sysroot_relative_path)
        self.assertEqual(self.sysroot_relative_path, sysroot_path.sysroot)

    def testChroot(self):
        """Tests that SysrootPath.chroot returns expected result."""
        sysroot_path = cros_fuzz.SysrootPath(self.sysroot_relative_path)
        expected = os.path.join(self.path_to_sysroot, self.basename)
        self.assertEqual(expected, sysroot_path.chroot)

    def testIsSysrootPath(self):
        """Tests that the IsSysrootPath can tell what is in the sysroot."""
        self.assertTrue(
            cros_fuzz.SysrootPath.IsPathInSysroot(self.path_to_sysroot)
        )
        self.assertTrue(
            cros_fuzz.SysrootPath.IsPathInSysroot(self.path_in_sysroot)
        )
        path_not_in_sysroot_1 = os.path.join(
            os.path.dirname(self.path_to_sysroot), self.basename
        )
        self.assertFalse(
            cros_fuzz.SysrootPath.IsPathInSysroot(path_not_in_sysroot_1)
        )
        path_not_in_sysroot_2 = os.path.join("/dir/build/amd64-generic")
        self.assertFalse(
            cros_fuzz.SysrootPath.IsPathInSysroot(path_not_in_sysroot_2)
        )

    def testFromChrootPathInSysroot(self):
        """Tests that FromChrootPathInSysroot converts paths properly."""
        # Test that it raises an assertion error when the path is not in the
        # sysroot.
        path_not_in_sysroot_1 = os.path.join(
            os.path.dirname(self.path_to_sysroot), "dir"
        )
        with self.assertRaises(AssertionError):
            cros_fuzz.SysrootPath.FromChrootPathInSysroot(path_not_in_sysroot_1)

        sysroot_path = cros_fuzz.SysrootPath.FromChrootPathInSysroot(
            self.path_in_sysroot
        )
        self.assertEqual(self.sysroot_relative_path, sysroot_path)


class GetPathForCopyTest(cros_test_lib.TestCase):
    """Tests GetPathForCopy."""

    def testGetPathForCopy(self):
        """Test that GetPathForCopy gives us the correct sysroot directory."""
        _SetPathToSysroot()
        directory = "/path/to/directory"
        parent = "parent"
        child = os.path.basename(directory)
        path_to_sysroot = cros_fuzz.SysrootPath.path_to_sysroot
        storage_directory = cros_fuzz.SCRIPT_STORAGE_DIRECTORY

        sysroot_path = cros_fuzz.GetPathForCopy(parent, child)

        expected_chroot_path = os.path.join(
            path_to_sysroot, "tmp", storage_directory, parent, child
        )
        self.assertEqual(expected_chroot_path, sysroot_path.chroot)

        expected_sysroot_path = os.path.join(
            "/", "tmp", storage_directory, parent, child
        )
        self.assertEqual(expected_sysroot_path, sysroot_path.sysroot)


class GetLibFuzzerOptionTest(cros_test_lib.TestCase):
    """Tests GetLibFuzzerOption."""

    def testGetLibFuzzerOption(self):
        """Tests that GetLibFuzzerOption returns a correct libFuzzer option."""
        expected = "-max_total_time=60"
        self.assertEqual(
            expected, cros_fuzz.GetLibFuzzerOption("max_total_time", 60)
        )


class LimitFuzzingTest(cros_test_lib.TestCase):
    """Tests LimitFuzzing."""

    def setUp(self):
        self.fuzz_command = ["./fuzzer", "-rss_limit_mb=4096"]
        self.corpus = None

    def _Helper(self, expected_command=None):
        """Calls LimitFuzzing and asserts fuzz_command equals |expected_command|.

        If |expected| is None, then it is set to self.fuzz_command before calling
        LimitFuzzing.
        """
        if expected_command is None:
            expected_command = self.fuzz_command[:]
        cros_fuzz.LimitFuzzing(self.fuzz_command, self.corpus)
        self.assertEqual(expected_command, self.fuzz_command)

    def testCommandHasMaxTotalTime(self):
        """Tests that no limit is added when user specifies -max_total_time."""
        self.fuzz_command.append("-max_total_time=60")
        self._Helper()

    def testCommandHasRuns(self):
        """Tests that no limit is added when user specifies -runs"""
        self.fuzz_command.append("-runs=1")
        self._Helper()

    def testCommandHasCorpus(self):
        """Tests that a limit is added when user specifies a corpus."""
        self.corpus = "corpus"
        expected = self.fuzz_command + ["-runs=0"]
        self._Helper(expected)

    def testNoLimitOrCorpus(self):
        """Tests that a limit is added when user specifies no corpus or limit."""
        expected = self.fuzz_command + [DEFAULT_MAX_TOTAL_TIME_OPTION]
        self._Helper(expected)


class RunSysrootCommandMockTestCase(cros_test_lib.MockTestCase):
    """Class for TestCases that call RunSysrootCommand."""

    def setUp(self):
        _SetPathToSysroot()
        self.expected_command = None
        self.expected_extra_env = None
        self.PatchObject(
            cros_fuzz,
            "RunSysrootCommand",
            side_effect=self.MockedRunSysrootCommand,
        )

    def MockedRunSysrootCommand(
        self, command, extra_env=None, **kwargs
    ):  # pylint: disable=unused-argument
        """The mocked version of RunSysrootCommand.

        Asserts |command| and |extra_env| are what is expected.
        """
        self.assertEqual(self.expected_command, command)
        self.assertEqual(self.expected_extra_env, extra_env)


class RunFuzzerTest(RunSysrootCommandMockTestCase):
    """Tests RunFuzzer."""

    def setUp(self):
        self.corpus_path = None
        self.fuzz_args = ""
        self.testcase_path = None
        self.expected_command = [
            cros_fuzz.GetFuzzerSysrootPath(FUZZ_TARGET).sysroot,
        ]
        self.expected_extra_env = {
            "ASAN_OPTIONS": "log_path=stderr:detect_odr_violation=0",
            "MSAN_OPTIONS": "log_path=stderr:detect_odr_violation=0",
            "UBSAN_OPTIONS": "log_path=stderr:detect_odr_violation=0",
        }

    def _Helper(self):
        """Calls RunFuzzer."""
        cros_fuzz.RunFuzzer(
            FUZZ_TARGET, self.corpus_path, self.fuzz_args, self.testcase_path
        )

    def testNoOptional(self):
        """Tests correct command and env used when not specifying optional."""
        self.expected_command.append(DEFAULT_MAX_TOTAL_TIME_OPTION)
        self._Helper()

    def testFuzzArgs(self):
        """Tests that the correct command is used when fuzz_args is specified."""
        fuzz_args = [DEFAULT_MAX_TOTAL_TIME_OPTION, "-fake_arg=fake_value"]
        self.expected_command.extend(fuzz_args)
        self.fuzz_args = " ".join(fuzz_args)
        self._Helper()

    def testTestCase(self):
        """Tests a testcase is used when specified."""
        self.testcase_path = "/path/to/testcase"
        self.expected_command.append(self.testcase_path)
        self._Helper()


class MergeProfrawTest(RunSysrootCommandMockTestCase):
    """Tests MergeProfraw."""

    def testMergeProfraw(self):
        """Tests that MergeProfraw works as expected."""
        # Parent class will assert that these commands are used.
        profdata_path = cros_fuzz.GetProfdataPath(FUZZ_TARGET)
        self.expected_command = [
            "llvm-profdata",
            "merge",
            "-sparse",
            cros_fuzz.DEFAULT_PROFRAW_PATH,
            "-o",
            profdata_path.sysroot,
        ]
        cros_fuzz.MergeProfraw(FUZZ_TARGET)


class GenerateCoverageReportTest(cros_test_lib.RunCommandTestCase):
    """Tests GenerateCoverageReport."""

    def setUp(self):
        _SetPathToSysroot()
        self.fuzzer_path = cros_fuzz.GetFuzzerSysrootPath(FUZZ_TARGET).chroot
        self.profdata_path = cros_fuzz.GetProfdataPath(FUZZ_TARGET)

    def testWithSharedLibraries(self):
        """Tests that right command is used when specifying shared libraries."""
        shared_libraries = ["shared_lib.so"]
        cros_fuzz.GenerateCoverageReport(FUZZ_TARGET, shared_libraries)
        instr_profile_option = "-instr-profile=%s" % self.profdata_path.chroot
        output_dir_option = "-output-dir=%s" % FUZZER_COVERAGE_PATH
        expected_command = [
            "llvm-cov",
            "show",
            "-object",
            self.fuzzer_path,
            "-object",
            "shared_lib.so",
            "-format=html",
            instr_profile_option,
            output_dir_option,
        ]
        self.assertCommandCalled(
            expected_command, stderr=True, debug_level=logging.DEBUG
        )

    def testNoSharedLibraries(self):
        """Tests the right coverage command is used without shared libraries."""
        shared_libraries = []
        cros_fuzz.GenerateCoverageReport(FUZZ_TARGET, shared_libraries)
        instr_profile_option = "-instr-profile=%s" % self.profdata_path.chroot
        output_dir_option = "-output-dir=%s" % FUZZER_COVERAGE_PATH
        expected_command = [
            "llvm-cov",
            "show",
            "-object",
            self.fuzzer_path,
            "-format=html",
            instr_profile_option,
            output_dir_option,
        ]
        self.assertCommandCalled(
            expected_command, stderr=True, debug_level=logging.DEBUG
        )


class RunSysrootCommandTest(cros_test_lib.RunCommandTestCase):
    """Tests RunSysrootCommand."""

    def testRunSysrootCommand(self):
        """Tests RunSysrootCommand creates a proper command to run in sysroot."""
        command = ["./fuzz", "-rss_limit_mb=4096"]
        sysroot_path = _SetPathToSysroot()
        cros_fuzz.RunSysrootCommand(command)
        expected_command = ["sudo", "--", "chroot", sysroot_path]
        expected_command.extend(command)
        self.assertCommandCalled(expected_command, debug_level=logging.DEBUG)


class GetBuildExtraEnvTest(cros_test_lib.TestCase):
    """Tests GetBuildExtraEnv."""

    TEST_ENV_VAR = "TEST_VAR"

    def testUseAndFeaturesNotClobbered(self):
        """Tests that values of certain environment variables are appended to."""
        vars_and_values = {"FEATURES": "foo", "USE": "bar"}
        for var, value in vars_and_values.items():
            os.environ[var] = value
        extra_env = cros_fuzz.GetBuildExtraEnv(cros_fuzz.BuildType.COVERAGE)
        for var, value in vars_and_values.items():
            self.assertIn(value, extra_env[var])

    def testCoverageBuild(self):
        """Tests that a proper environment is returned for a coverage build."""
        extra_env = cros_fuzz.GetBuildExtraEnv(cros_fuzz.BuildType.COVERAGE)
        for expected_flag in ["fuzzer", "coverage", "asan"]:
            self.assertIn(expected_flag, extra_env["USE"])
        self.assertIn("noclean", extra_env["FEATURES"])


def _SetPathToSysroot():
    """Calls SysrootPath.SetPathToSysroot and returns result."""
    return cros_fuzz.SysrootPath.SetPathToSysroot(BOARD)