diff options
| -rw-r--r-- | cloudinit/ssh_util.py | 35 | ||||
| -rw-r--r-- | tests/integration_tests/modules/test_ssh_keysfile.py | 132 |
2 files changed, 146 insertions, 21 deletions
diff --git a/cloudinit/ssh_util.py b/cloudinit/ssh_util.py index b8a3c8f7..9ccadf09 100644 --- a/cloudinit/ssh_util.py +++ b/cloudinit/ssh_util.py @@ -321,23 +321,48 @@ def check_create_path(username, filename, strictmodes): home_folder = os.path.dirname(user_pwent.pw_dir) for directory in directories: parent_folder += "/" + directory - if home_folder.startswith(parent_folder): + + # security check, disallow symlinks in the AuthorizedKeysFile path. + if os.path.islink(parent_folder): + LOG.debug( + "Invalid directory. Symlink exists in path: %s", + parent_folder) + return False + + if os.path.isfile(parent_folder): + LOG.debug( + "Invalid directory. File exists in path: %s", + parent_folder) + return False + + if (home_folder.startswith(parent_folder) or + parent_folder == user_pwent.pw_dir): continue - if not os.path.isdir(parent_folder): + if not os.path.exists(parent_folder): # directory does not exist, and permission so far are good: # create the directory, and make it accessible by everyone # but owned by root, as it might be used by many users. with util.SeLinuxGuard(parent_folder): - os.makedirs(parent_folder, mode=0o755, exist_ok=True) - util.chownbyid(parent_folder, root_pwent.pw_uid, - root_pwent.pw_gid) + mode = 0o755 + uid = root_pwent.pw_uid + gid = root_pwent.pw_gid + if parent_folder.startswith(user_pwent.pw_dir): + mode = 0o700 + uid = user_pwent.pw_uid + gid = user_pwent.pw_gid + os.makedirs(parent_folder, mode=mode, exist_ok=True) + util.chownbyid(parent_folder, uid, gid) permissions = check_permissions(username, parent_folder, filename, False, strictmodes) if not permissions: return False + if os.path.islink(filename) or os.path.isdir(filename): + LOG.debug("%s is not a file!", filename) + return False + # check the file if not os.path.exists(filename): # if file does not exist: we need to create it, since the diff --git a/tests/integration_tests/modules/test_ssh_keysfile.py b/tests/integration_tests/modules/test_ssh_keysfile.py index f82d7649..3159feb9 100644 --- a/tests/integration_tests/modules/test_ssh_keysfile.py +++ b/tests/integration_tests/modules/test_ssh_keysfile.py @@ -10,10 +10,10 @@ TEST_USER1_KEYS = get_test_rsa_keypair('test1') TEST_USER2_KEYS = get_test_rsa_keypair('test2') TEST_DEFAULT_KEYS = get_test_rsa_keypair('test3') -USERDATA = """\ +_USERDATA = """\ #cloud-config bootcmd: - - sed -i 's;#AuthorizedKeysFile.*;AuthorizedKeysFile /etc/ssh/authorized_keys %h/.ssh/authorized_keys2;' /etc/ssh/sshd_config + - {bootcmd} ssh_authorized_keys: - {default} users: @@ -24,27 +24,17 @@ users: - name: test_user2 ssh_authorized_keys: - {user2} -""".format( # noqa: E501 +""".format( + bootcmd='{bootcmd}', default=TEST_DEFAULT_KEYS.public_key, user1=TEST_USER1_KEYS.public_key, user2=TEST_USER2_KEYS.public_key, ) -@pytest.mark.ubuntu -@pytest.mark.user_data(USERDATA) -def test_authorized_keys(client: IntegrationInstance): - expected_keys = [ - ('test_user1', '/home/test_user1/.ssh/authorized_keys2', - TEST_USER1_KEYS), - ('test_user2', '/home/test_user2/.ssh/authorized_keys2', - TEST_USER2_KEYS), - ('ubuntu', '/home/ubuntu/.ssh/authorized_keys2', - TEST_DEFAULT_KEYS), - ('root', '/root/.ssh/authorized_keys2', TEST_DEFAULT_KEYS), - ] - +def common_verify(client, expected_keys): for user, filename, keys in expected_keys: + # Ensure key is in the key file contents = client.read_from_file(filename) if user in ['ubuntu', 'root']: # Our personal public key gets added by pycloudlib @@ -83,3 +73,113 @@ def test_authorized_keys(client: IntegrationInstance): look_for_keys=False, allow_agent=False, ) + + # Ensure we haven't messed with any /home permissions + # See LP: #1940233 + home_dir = '/home/{}'.format(user) + home_perms = '755' + if user == 'root': + home_dir = '/root' + home_perms = '700' + assert '{} {}'.format(user, home_perms) == client.execute( + 'stat -c "%U %a" {}'.format(home_dir) + ) + if client.execute("test -d {}/.ssh".format(home_dir)).ok: + assert '{} 700'.format(user) == client.execute( + 'stat -c "%U %a" {}/.ssh'.format(home_dir) + ) + assert '{} 600'.format(user) == client.execute( + 'stat -c "%U %a" {}'.format(filename) + ) + + # Also ensure ssh-keygen works as expected + client.execute('mkdir {}/.ssh'.format(home_dir)) + assert client.execute( + "ssh-keygen -b 2048 -t rsa -f {}/.ssh/id_rsa -q -N ''".format( + home_dir) + ).ok + assert client.execute('test -f {}/.ssh/id_rsa'.format(home_dir)) + assert client.execute('test -f {}/.ssh/id_rsa.pub'.format(home_dir)) + + assert 'root 755' == client.execute('stat -c "%U %a" /home') + + +DEFAULT_KEYS_USERDATA = _USERDATA.format(bootcmd='""') + + +@pytest.mark.ubuntu +@pytest.mark.user_data(DEFAULT_KEYS_USERDATA) +def test_authorized_keys_default(client: IntegrationInstance): + expected_keys = [ + ('test_user1', '/home/test_user1/.ssh/authorized_keys', + TEST_USER1_KEYS), + ('test_user2', '/home/test_user2/.ssh/authorized_keys', + TEST_USER2_KEYS), + ('ubuntu', '/home/ubuntu/.ssh/authorized_keys', + TEST_DEFAULT_KEYS), + ('root', '/root/.ssh/authorized_keys', TEST_DEFAULT_KEYS), + ] + common_verify(client, expected_keys) + + +AUTHORIZED_KEYS2_USERDATA = _USERDATA.format(bootcmd=( + "sed -i 's;#AuthorizedKeysFile.*;AuthorizedKeysFile " + "/etc/ssh/authorized_keys %h/.ssh/authorized_keys2;' " + "/etc/ssh/sshd_config")) + + +@pytest.mark.ubuntu +@pytest.mark.user_data(AUTHORIZED_KEYS2_USERDATA) +def test_authorized_keys2(client: IntegrationInstance): + expected_keys = [ + ('test_user1', '/home/test_user1/.ssh/authorized_keys2', + TEST_USER1_KEYS), + ('test_user2', '/home/test_user2/.ssh/authorized_keys2', + TEST_USER2_KEYS), + ('ubuntu', '/home/ubuntu/.ssh/authorized_keys2', + TEST_DEFAULT_KEYS), + ('root', '/root/.ssh/authorized_keys2', TEST_DEFAULT_KEYS), + ] + common_verify(client, expected_keys) + + +NESTED_KEYS_USERDATA = _USERDATA.format(bootcmd=( + "sed -i 's;#AuthorizedKeysFile.*;AuthorizedKeysFile " + "/etc/ssh/authorized_keys %h/foo/bar/ssh/keys;' " + "/etc/ssh/sshd_config")) + + +@pytest.mark.ubuntu +@pytest.mark.user_data(NESTED_KEYS_USERDATA) +def test_nested_keys(client: IntegrationInstance): + expected_keys = [ + ('test_user1', '/home/test_user1/foo/bar/ssh/keys', + TEST_USER1_KEYS), + ('test_user2', '/home/test_user2/foo/bar/ssh/keys', + TEST_USER2_KEYS), + ('ubuntu', '/home/ubuntu/foo/bar/ssh/keys', + TEST_DEFAULT_KEYS), + ('root', '/root/foo/bar/ssh/keys', TEST_DEFAULT_KEYS), + ] + common_verify(client, expected_keys) + + +EXTERNAL_KEYS_USERDATA = _USERDATA.format(bootcmd=( + "sed -i 's;#AuthorizedKeysFile.*;AuthorizedKeysFile " + "/etc/ssh/authorized_keys /etc/ssh/authorized_keys/%u/keys;' " + "/etc/ssh/sshd_config")) + + +@pytest.mark.ubuntu +@pytest.mark.user_data(EXTERNAL_KEYS_USERDATA) +def test_external_keys(client: IntegrationInstance): + expected_keys = [ + ('test_user1', '/etc/ssh/authorized_keys/test_user1/keys', + TEST_USER1_KEYS), + ('test_user2', '/etc/ssh/authorized_keys/test_user2/keys', + TEST_USER2_KEYS), + ('ubuntu', '/etc/ssh/authorized_keys/ubuntu/keys', + TEST_DEFAULT_KEYS), + ('root', '/etc/ssh/authorized_keys/root/keys', TEST_DEFAULT_KEYS), + ] + common_verify(client, expected_keys) |