1# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging
6import os
7import pwd
8import stat
9
10from autotest_lib.client.bin import test, utils
11from autotest_lib.client.common_lib import error
12from autotest_lib.client.common_lib.cros import chrome
13from autotest_lib.client.cros import cryptohome
14
15
16class security_ProfilePermissions(test.test):
17    """Check permissions of files of logged in and guest user."""
18    version = 1
19    _HOMEDIR_MODE = 0710
20
21    def initialize(self, logged_in):
22        self._logged_in = logged_in
23
24    def check_owner_mode(self, path, expected_owner, expected_mode):
25        """
26        Checks if the file/directory at 'path' is owned by 'expected_owner'
27        with permissions matching 'expected_mode'.
28        Returns True if they match, else False.
29        Logs any mismatches to logging.error.
30
31        @param path: file path to test.
32        @param expected_owner: expected owner of the file.
33        @param expected_mode: expected permission mode of the file.
34
35        """
36        s = os.stat(path)
37        actual_owner = pwd.getpwuid(s.st_uid).pw_name
38        actual_mode = stat.S_IMODE(s.st_mode)
39        if (expected_owner != actual_owner or
40            expected_mode != actual_mode):
41            logging.error("%s - Expected %s:%s, saw %s:%s",
42                         path, expected_owner, oct(expected_mode),
43                         actual_owner, oct(actual_mode))
44            return False
45        else:
46            return True
47
48
49    def run_once(self):
50        with chrome.Chrome(logged_in=self._logged_in) as cr:
51            username = (cr.username if self._logged_in
52                                    else cryptohome.GUEST_USER_NAME)
53
54            """Check permissions within cryptohome for anything too permissive.
55            """
56            passes = []
57
58            homepath = "/home/chronos"
59            passes.append(self.check_owner_mode(homepath, "chronos", 0755))
60
61            user_mountpt = cryptohome.user_path(username)
62            passes.append(self.check_owner_mode(user_mountpt, "chronos",
63                                                self._HOMEDIR_MODE))
64
65            # TODO(benchan): Refactor the following code to use some helper
66            # functions instead of find commands.
67
68            # An array of shell commands, each representing a test that
69            # passes if it emits no output. The first test is the main one.
70            # In general, writable by anyone else is bad, as is owned by
71            # anyone else. Any exceptions to that are pruned out of the
72            # first test and checked individually by subsequent tests.
73            cmds = [
74                ('find -L "%s" -path "%s" -o '
75                 # Avoid false-positives on SingletonLock, SingletonCookie, etc.
76                 ' \\( -name "Singleton*" -a -type l \\) -o '
77                 ' -path "%s/user" -prune -o '
78                 ' -path "%s/Downloads" -prune -o '
79                 ' -path "%s/flimflam" -prune -o '
80                 ' -path "%s/shill" -prune -o '
81                 ' -path "%s/.chaps" -prune -o '
82                 ' -path "%s/u-*" -prune -o '
83                 ' -path "%s/crash" -prune -o '
84                 ' \\( -perm /022 -o \\! -user chronos \\) -ls') %
85                (homepath, homepath, homepath, user_mountpt, user_mountpt,
86                user_mountpt, user_mountpt, homepath, homepath),
87                # /home/chronos/user and /home/chronos/user/Downloads are owned
88                # by the chronos-access group and with a group execute
89                # permission.
90                'find -L "%s" -maxdepth 0 \\( \\! -perm 710 '
91                '-o \\! -user chronos -o \\! -group chronos-access \\) -ls' %
92                user_mountpt,
93                'find -L "%s/Downloads" -maxdepth 0 \\( \\! -perm 710 '
94                '-o \\! -user chronos -o \\! -group chronos-access \\) -ls' %
95                user_mountpt,
96                'find -L "%s/flimflam" \\( -perm /077 -o \\! -user root \\) -ls'
97                % user_mountpt,
98                'find -L "%s/shill" \\( -perm /077 -o \\! -user root \\) -ls' %
99                user_mountpt,
100                'find -L "%s/.chaps -name auth_data_salt -prune -o '
101                '\\! -user chaps -o \\! -group chronos-access -o -perm /027 -ls'
102                % user_mountpt,
103                'find -L "%s/.chaps -name auth_data_salt -a '
104                '\\( \\! -user root -o -perm /077 \\) -ls' % user_mountpt,
105            ]
106
107            for cmd in cmds:
108                cmd_output = utils.system_output(cmd, ignore_status=True)
109                if cmd_output:
110                    passes.append(False)
111                    logging.error(cmd_output)
112
113            # This next section only applies if we have a real vault mounted
114            # (ie, not a BWSI tmpfs).
115            if cryptohome.is_permanent_vault_mounted(username):
116                # Also check the permissions of the underlying vault and
117                # supporting directory structure.
118                mountpath = cryptohome.get_mounted_vault_path(username)
119
120                # On ecryptfs backend, there's a 'vault' directory storing the
121                # encrypted data. If it exists, check its ownership as well.
122                vaultpath = os.path.join(mountpath, '../vault')
123                if os.path.exists(vaultpath):
124                    passes.append(self.check_owner_mode(vaultpath,
125                                                        "root", 0700))
126                passes.append(self.check_owner_mode(mountpath, "root", 0700))
127                passes.append(self.check_owner_mode(mountpath + "/../master.0",
128                                                    "root", 0600))
129                passes.append(self.check_owner_mode(mountpath + "/../",
130                                                    "root", 0700))
131                passes.append(self.check_owner_mode(mountpath + "/../../",
132                                                    "root", 0700))
133
134            if False in passes:
135                raise error.TestFail(
136                    'Bad permissions found on cryptohome files')
137