| # Copyright (c) 2012 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. |
| |
| from autotest_lib.client.bin import test |
| from autotest_lib.client.bin import utils |
| from autotest_lib.client.common_lib import error |
| |
| import logging |
| import os |
| import errno |
| |
| """A test verifying processes have non-executable stacks |
| |
| Examines the /proc/$pid/maps file of all running processes for the |
| stack segment's markings. If "x" is found, it fails. |
| """ |
| |
| class security_RuntimeExecStack(test.test): |
| version = 1 |
| |
| def execstack(self, maps): |
| """Reads maps fd for stack markings |
| |
| Args: |
| pid: a string containing the pid to be tested. |
| |
| Returns: tuple of code and maps text relevant that code. |
| 0: stack not executable |
| 1: stack executable |
| 2: stack perms insane |
| 3: stack missing |
| """ |
| contents = "" |
| for line in maps: |
| line = line.strip() |
| contents += line + "\n" |
| |
| if not line.endswith('[stack]'): |
| continue |
| |
| perms = line.split(' ', 2)[1] |
| |
| # Stack segment is executable. |
| if 'x' in perms: |
| return 1, line |
| |
| # Sanity check we have stack segment perms. |
| if not 'w' in perms: |
| return 2, line |
| |
| # Stack segment is non-executable. |
| return 0, line |
| |
| # Should be impossible: no stack segment seen. |
| return 3, contents |
| |
| def run_once(self): |
| failed = set([]) |
| |
| for pid in os.listdir("/proc"): |
| maps_path = "/proc/%s/maps" % (pid) |
| # Is this a pid directory? |
| if not os.path.exists(maps_path): |
| continue |
| # Is this a kernel thread? |
| try: |
| link = os.readlink("/proc/%s/exe" % (pid)) |
| except OSError, e: |
| if e.errno == errno.ENOENT: |
| continue |
| try: |
| maps = open(maps_path) |
| cmd = open("/proc/%s/cmdline" % (pid)).read() |
| except: |
| # Allow the path to vanish out from under us. If |
| # we've failed for any other reason, raise the failure. |
| if os.path.exists(maps_path): |
| raise |
| logging.debug('ignored: pid %s vanished' % (pid)) |
| continue |
| |
| # Clean up cmdline for reporting. |
| cmd = cmd.replace('\x00', ' ') |
| exe = cmd |
| if ' ' in exe: |
| exe = exe[:exe.index(' ')] |
| |
| # Check the stack segment. |
| stack, report = self.execstack(maps) |
| |
| # Report outcome. |
| if stack == 0: |
| logging.debug('ok: %s %s %s' % (pid, exe, report)) |
| else: |
| logging.info('FAIL: %s %s %s' % (pid, cmd, report)) |
| failed.add(exe) |
| |
| if len(failed) != 0: |
| msg = 'Bad stacks segments: %s' % (', '.join(failed)) |
| raise error.TestFail(msg) |