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build/android/pylib/linker/test_case.py

Index: build/android/pylib/linker/test_case.py
diff --git a/build/android/pylib/linker/test_case.py b/build/android/pylib/linker/test_case.py
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+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Base class for linker-specific test cases.
+
+   The custom dynamic linker can only be tested through a custom test case
+   for various technical reasons:
+
+     - It's an 'invisible feature', i.e. it doesn't expose a new API or
+       behaviour, all it does is save RAM when loading native libraries.
+
+     - Checking that it works correctly requires several things that do not
+       fit the existing GTest-based and instrumentation-based tests:
+
+         - Native test code needs to be run in both the browser and renderer
+           process at the same time just after loading native libraries, in
+           a completely asynchronous way.
+
+         - Each test case requires restarting a whole new application process
+           with a different command-line.
+
+         - Enabling test support in the Linker code requires building a special
+           APK with a flag to activate special test-only support code in the
+           Linker code itself.
+
+       Host-driven tests have also been tried, but since they're really
+       sub-classes of instrumentation tests, they didn't work well either.
+
+   To build and run the linker tests, do the following:
+
+     ninja -C out/Debug chromium_linker_test_apk
+     build/android/test_runner.py linker
+
+"""
+# pylint: disable=R0201
+
+import logging
+import os
+import re
+import time
+
+from pylib import constants
+from pylib.base import base_test_result
+from pylib.device import device_errors
+from pylib.device import intent
+
+
+ResultType = base_test_result.ResultType
+
+_PACKAGE_NAME = 'org.chromium.chromium_linker_test_apk'
+_ACTIVITY_NAME = '.ChromiumLinkerTestActivity'
+_COMMAND_LINE_FILE = '/data/local/tmp/chromium-linker-test-command-line'
+
+# Path to the Linker.java source file.
+_LINKER_JAVA_SOURCE_PATH = (
+    'base/android/java/src/org/chromium/base/library_loader/Linker.java')
+
+# A regular expression used to extract the browser shared RELRO configuration
+# from the Java source file above.
+_RE_LINKER_BROWSER_CONFIG = re.compile(
+    r'.*BROWSER_SHARED_RELRO_CONFIG\s+=\s+' +
+        r'BROWSER_SHARED_RELRO_CONFIG_(\S+)\s*;.*',
+    re.MULTILINE | re.DOTALL)
+
+# Logcat filters used during each test. Only the 'chromium' one is really
+# needed, but the logs are added to the TestResult in case of error, and
+# it is handy to have the 'chromium_android_linker' ones as well when
+# troubleshooting.
+_LOGCAT_FILTERS = ['*:s', 'chromium:v', 'chromium_android_linker:v']
+#_LOGCAT_FILTERS = ['*:v']  ## DEBUG
+
+# Regular expression used to match status lines in logcat.
+_RE_BROWSER_STATUS_LINE = re.compile(r' BROWSER_LINKER_TEST: (FAIL|SUCCESS)$')
+_RE_RENDERER_STATUS_LINE = re.compile(r' RENDERER_LINKER_TEST: (FAIL|SUCCESS)$')
+
+# Regular expression used to mach library load addresses in logcat.
+_RE_LIBRARY_ADDRESS = re.compile(
+    r'(BROWSER|RENDERER)_LIBRARY_ADDRESS: (\S+) ([0-9A-Fa-f]+)')
+
+
+def _GetBrowserSharedRelroConfig():
+  """Returns a string corresponding to the Linker's configuration of shared
+     RELRO sections in the browser process. This parses the Java linker source
+     file to get the appropriate information.
+  Return:
+      None in case of error (e.g. could not locate the source file).
+     'NEVER' if the browser process shall never use shared RELROs.
+     'LOW_RAM_ONLY' if if uses it only on low-end devices.
+     'ALWAYS' if it always uses a shared RELRO.
+  """
+  source_path = \
+      os.path.join(constants.DIR_SOURCE_ROOT, _LINKER_JAVA_SOURCE_PATH)
+  if not os.path.exists(source_path):
+    logging.error('Could not find linker source file: ' + source_path)
+    return None
+
+  with open(source_path) as f:
+    configs = _RE_LINKER_BROWSER_CONFIG.findall(f.read())
+    if not configs:
+      logging.error(
+          'Can\'t find browser shared RELRO configuration value in ' + \
+          source_path)
+      return None
+
+    if configs[0] not in ['NEVER', 'LOW_RAM_ONLY', 'ALWAYS']:
+      logging.error('Unexpected browser config value: ' + configs[0])
+      return None
+
+    logging.info('Found linker browser shared RELRO config: ' + configs[0])
+    return configs[0]
+
+
+def _StartActivityAndWaitForLinkerTestStatus(device, timeout):
+  """Force-start an activity and wait up to |timeout| seconds until the full
+     linker test status lines appear in the logcat, recorded through |device|.
+  Args:
+    device: A DeviceUtils instance.
+    timeout: Timeout in seconds
+  Returns:
+    A (status, logs) tuple, where status is a ResultType constant, and logs
+    if the final logcat output as a string.
+  """
+
+  # 1. Start recording logcat with appropriate filters.
+  with device.GetLogcatMonitor(filter_specs=_LOGCAT_FILTERS) as logmon:
+
+    # 2. Force-start activity.
+    device.StartActivity(
+        intent.Intent(package=_PACKAGE_NAME, activity=_ACTIVITY_NAME),
+        force_stop=True)
+
+    # 3. Wait up to |timeout| seconds until the test status is in the logcat.
+    result = ResultType.PASS
+    try:
+      browser_match = logmon.WaitFor(_RE_BROWSER_STATUS_LINE, timeout=timeout)
+      logging.debug('Found browser match: %s', browser_match.group(0))
+      renderer_match = logmon.WaitFor(_RE_RENDERER_STATUS_LINE,
+                                      timeout=timeout)
+      logging.debug('Found renderer match: %s', renderer_match.group(0))
+      if (browser_match.group(1) != 'SUCCESS'
+          or renderer_match.group(1) != 'SUCCESS'):
+        result = ResultType.FAIL
+    except device_errors.CommandTimeoutError:
+      result = ResultType.TIMEOUT
+
+    return result, '\n'.join(device.adb.Logcat(dump=True))
+
+
+class LibraryLoadMap(dict):
+  """A helper class to pretty-print a map of library names to load addresses."""
+  def __str__(self):
+    items = ['\'%s\': 0x%x' % (name, address) for \
+        (name, address) in self.iteritems()]
+    return '{%s}' % (', '.join(items))
+
+  def __repr__(self):
+    return 'LibraryLoadMap(%s)' % self.__str__()
+
+
+class AddressList(list):
+  """A helper class to pretty-print a list of load addresses."""
+  def __str__(self):
+    items = ['0x%x' % address for address in self]
+    return '[%s]' % (', '.join(items))
+
+  def __repr__(self):
+    return 'AddressList(%s)' % self.__str__()
+
+
+def _ExtractLibraryLoadAddressesFromLogcat(logs):
+  """Extract the names and addresses of shared libraries loaded in the
+     browser and renderer processes.
+  Args:
+    logs: A string containing logcat output.
+  Returns:
+    A tuple (browser_libs, renderer_libs), where each item is a map of
+    library names (strings) to library load addresses (ints), for the
+    browser and renderer processes, respectively.
+  """
+  browser_libs = LibraryLoadMap()
+  renderer_libs = LibraryLoadMap()
+  for m in _RE_LIBRARY_ADDRESS.finditer(logs):
+    process_type, lib_name, lib_address = m.groups()
+    lib_address = int(lib_address, 16)
+    if process_type == 'BROWSER':
+      browser_libs[lib_name] = lib_address
+    elif process_type == 'RENDERER':
+      renderer_libs[lib_name] = lib_address
+    else:
+      assert False, 'Invalid process type'
+
+  return browser_libs, renderer_libs
+
+
+def _CheckLoadAddressRandomization(lib_map_list, process_type):
+  """Check that a map of library load addresses is random enough.
+  Args:
+    lib_map_list: a list of dictionaries that map library names (string)
+      to load addresses (int). Each item in the list corresponds to a
+      different run / process start.
+    process_type: a string describing the process type.
+  Returns:
+    (status, logs) tuple, where <status> is True iff the load addresses are
+    randomized, False otherwise, and <logs> is a string containing an error
+    message detailing the libraries that are not randomized properly.
+  """
+  # Collect, for each library, its list of load addresses.
+  lib_addr_map = {}
+  for lib_map in lib_map_list:
+    for lib_name, lib_address in lib_map.iteritems():
+      if lib_name not in lib_addr_map:
+        lib_addr_map[lib_name] = AddressList()
+      lib_addr_map[lib_name].append(lib_address)
+
+  logging.info('%s library load map: %s', process_type, lib_addr_map)
+
+  # For each library, check the randomness of its load addresses.
+  bad_libs = {}
+  for lib_name, lib_address_list in lib_addr_map.iteritems():
+    # If all addresses are different, skip to next item.
+    lib_address_set = set(lib_address_list)
+    # Consider that if there is more than one pair of identical addresses in
+    # the list, then randomization is broken.
+    if len(lib_address_set) < len(lib_address_list) - 1:
+      bad_libs[lib_name] = lib_address_list
+
+
+  if bad_libs:
+    return False, '%s libraries failed randomization: %s' % \
+        (process_type, bad_libs)
+
+  return True, '%s libraries properly randomized: %s' % \
+      (process_type, lib_addr_map)
+
+
+class LinkerTestCaseBase(object):
+  """Base class for linker test cases."""
+
+  def __init__(self, is_low_memory=False):
+    """Create a test case.
+    Args:
+      is_low_memory: True to simulate a low-memory device, False otherwise.
+    """
+    self.is_low_memory = is_low_memory
+    if is_low_memory:
+      test_suffix = 'ForLowMemoryDevice'
+    else:
+      test_suffix = 'ForRegularDevice'
+    class_name = self.__class__.__name__
+    self.qualified_name = '%s.%s' % (class_name, test_suffix)
+    self.tagged_name = self.qualified_name
+
+  def _RunTest(self, _device):
+    """Run the test, must be overriden.
+    Args:
+      _device: A DeviceUtils interface.
+    Returns:
+      A (status, log) tuple, where <status> is a ResultType constant, and <log>
+      is the logcat output captured during the test in case of error, or None
+      in case of success.
+    """
+    return ResultType.FAIL, 'Unimplemented _RunTest() method!'
+
+  def Run(self, device):
+    """Run the test on a given device.
+    Args:
+      device: Name of target device where to run the test.
+    Returns:
+      A base_test_result.TestRunResult() instance.
+    """
+    margin = 8
+    print '[ %-*s ] %s' % (margin, 'RUN', self.tagged_name)
+    logging.info('Running linker test: %s', self.tagged_name)
+
+    # Create command-line file on device.
+    command_line_flags = ''
+    if self.is_low_memory:
+      command_line_flags = '--low-memory-device'
+    device.WriteFile(_COMMAND_LINE_FILE, command_line_flags)
+
+    # Run the test.
+    status, logs = self._RunTest(device)
+
+    result_text = 'OK'
+    if status == ResultType.FAIL:
+      result_text = 'FAILED'
+    elif status == ResultType.TIMEOUT:
+      result_text = 'TIMEOUT'
+    print '[ %*s ] %s' % (margin, result_text, self.tagged_name)
+
+    results = base_test_result.TestRunResults()
+    results.AddResult(
+        base_test_result.BaseTestResult(
+            self.tagged_name,
+            status,
+            log=logs))
+
+    return results
+
+  def __str__(self):
+    return self.tagged_name
+
+  def __repr__(self):
+    return self.tagged_name
+
+
+class LinkerSharedRelroTest(LinkerTestCaseBase):
+  """A linker test case to check the status of shared RELRO sections.
+
+    The core of the checks performed here are pretty simple:
+
+      - Clear the logcat and start recording with an appropriate set of filters.
+      - Create the command-line appropriate for the test-case.
+      - Start the activity (always forcing a cold start).
+      - Every second, look at the current content of the filtered logcat lines
+        and look for instances of the following:
+
+            BROWSER_LINKER_TEST: <status>
+            RENDERER_LINKER_TEST: <status>
+
+        where <status> can be either FAIL or SUCCESS. These lines can appear
+        in any order in the logcat. Once both browser and renderer status are
+        found, stop the loop. Otherwise timeout after 30 seconds.
+
+        Note that there can be other lines beginning with BROWSER_LINKER_TEST:
+        and RENDERER_LINKER_TEST:, but are not followed by a <status> code.
+
+      - The test case passes if the <status> for both the browser and renderer
+        process are SUCCESS. Otherwise its a fail.
+  """
+  def _RunTest(self, device):
+    # Wait up to 30 seconds until the linker test status is in the logcat.
+    return _StartActivityAndWaitForLinkerTestStatus(device, timeout=30)
+
+
+class LinkerLibraryAddressTest(LinkerTestCaseBase):
+  """A test case that verifies library load addresses.
+
+     The point of this check is to ensure that the libraries are loaded
+     according to the following rules:
+
+     - For low-memory devices, they should always be loaded at the same address
+       in both browser and renderer processes, both below 0x4000_0000.
+
+     - For regular devices, the browser process should load libraries above
+       0x4000_0000, and renderer ones below it.
+  """
+  def _RunTest(self, device):
+    result, logs = _StartActivityAndWaitForLinkerTestStatus(device, timeout=30)
+
+    # Return immediately in case of timeout.
+    if result == ResultType.TIMEOUT:
+      return result, logs
+
+    # Collect the library load addresses in the browser and renderer processes.
+    browser_libs, renderer_libs = _ExtractLibraryLoadAddressesFromLogcat(logs)
+
+    logging.info('Browser libraries: %s', browser_libs)
+    logging.info('Renderer libraries: %s', renderer_libs)
+
+    # Check that the same libraries are loaded into both processes:
+    browser_set = set(browser_libs.keys())
+    renderer_set = set(renderer_libs.keys())
+    if browser_set != renderer_set:
+      logging.error('Library set mistmach browser=%s renderer=%s',
+          browser_libs.keys(), renderer_libs.keys())
+      return ResultType.FAIL, logs
+
+    # And that there are not empty.
+    if not browser_set:
+      logging.error('No libraries loaded in any process!')
+      return ResultType.FAIL, logs
+
+    # Check that the renderer libraries are loaded at 'low-addresses'. i.e.
+    # below 0x4000_0000, for every kind of device.
+    memory_boundary = 0x40000000
+    bad_libs = []
+    for lib_name, lib_address in renderer_libs.iteritems():
+      if lib_address >= memory_boundary:
+        bad_libs.append((lib_name, lib_address))
+
+    if bad_libs:
+      logging.error('Renderer libraries loaded at high addresses: %s', bad_libs)
+      return ResultType.FAIL, logs
+
+    browser_config = _GetBrowserSharedRelroConfig()
+    if not browser_config:
+      return ResultType.FAIL, 'Bad linker source configuration'
+
+    if browser_config == 'ALWAYS' or \
+        (browser_config == 'LOW_RAM_ONLY' and self.is_low_memory):
+      # The libraries must all be loaded at the same addresses. This also
+      # implicitly checks that the browser libraries are at low addresses.
+      addr_mismatches = []
+      for lib_name, lib_address in browser_libs.iteritems():
+        lib_address2 = renderer_libs[lib_name]
+        if lib_address != lib_address2:
+          addr_mismatches.append((lib_name, lib_address, lib_address2))
+
+      if addr_mismatches:
+        logging.error('Library load address mismatches: %s',
+            addr_mismatches)
+        return ResultType.FAIL, logs
+
+    # Otherwise, check that libraries are loaded at 'high-addresses'.
+    # Note that for low-memory devices, the previous checks ensure that they
+    # were loaded at low-addresses.
+    else:
+      bad_libs = []
+      for lib_name, lib_address in browser_libs.iteritems():
+        if lib_address < memory_boundary:
+          bad_libs.append((lib_name, lib_address))
+
+      if bad_libs:
+        logging.error('Browser libraries loaded at low addresses: %s', bad_libs)
+        return ResultType.FAIL, logs
+
+    # Everything's ok.
+    return ResultType.PASS, logs
+
+
+class LinkerRandomizationTest(LinkerTestCaseBase):
+  """A linker test case to check that library load address randomization works
+     properly between successive starts of the test program/activity.
+
+     This starts the activity several time (each time forcing a new process
+     creation) and compares the load addresses of the libraries in them to
+     detect that they have changed.
+
+     In theory, two successive runs could (very rarely) use the same load
+     address, so loop 5 times and compare the values there. It is assumed
+     that if there are more than one pair of identical addresses, then the
+     load addresses are not random enough for this test.
+  """
+  def _RunTest(self, device):
+    max_loops = 5
+    browser_lib_map_list = []
+    renderer_lib_map_list = []
+    logs_list = []
+    for _ in range(max_loops):
+      # Start the activity.
+      result, logs = _StartActivityAndWaitForLinkerTestStatus(
+          device, timeout=30)
+      if result == ResultType.TIMEOUT:
+        # Something bad happened. Return immediately.
+        return result, logs
+
+      # Collect library addresses.
+      browser_libs, renderer_libs = _ExtractLibraryLoadAddressesFromLogcat(logs)
+      browser_lib_map_list.append(browser_libs)
+      renderer_lib_map_list.append(renderer_libs)
+      logs_list.append(logs)
+
+    # Check randomization in the browser libraries.
+    logs = '\n'.join(logs_list)
+
+    browser_status, browser_logs = _CheckLoadAddressRandomization(
+        browser_lib_map_list, 'Browser')
+
+    renderer_status, renderer_logs = _CheckLoadAddressRandomization(
+        renderer_lib_map_list, 'Renderer')
+
+    browser_config = _GetBrowserSharedRelroConfig()
+    if not browser_config:
+      return ResultType.FAIL, 'Bad linker source configuration'
+
+    if not browser_status:
+      if browser_config == 'ALWAYS' or \
+          (browser_config == 'LOW_RAM_ONLY' and self.is_low_memory):
+        return ResultType.FAIL, browser_logs
+
+      # IMPORTANT NOTE: The system's ASLR implementation seems to be very poor
+      # when starting an activity process in a loop with "adb shell am start".
+      #
+      # When simulating a regular device, loading libraries in the browser
+      # process uses a simple mmap(NULL, ...) to let the kernel device where to
+      # load the file (this is similar to what System.loadLibrary() does).
+      #
+      # Unfortunately, at least in the context of this test, doing so while
+      # restarting the activity with the activity manager very, very, often
+      # results in the system using the same load address for all 5 runs, or
+      # sometimes only 4 out of 5.
+      #
+      # This has been tested experimentally on both Android 4.1.2 and 4.3.
+      #
+      # Note that this behaviour doesn't seem to happen when starting an
+      # application 'normally', i.e. when using the application launcher to
+      # start the activity.
+      logging.info('Ignoring system\'s low randomization of browser libraries' +
+                   ' for regular devices')
+
+    if not renderer_status:
+      return ResultType.FAIL, renderer_logs
+
+    return ResultType.PASS, logs