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authorJames Falcon <therealfalcon@gmail.com>2021-08-20 17:09:49 -0500
committerGitHub <noreply@github.com>2021-08-20 17:09:49 -0500
commit7d3f5d750f6111c2716143364ea33486df67c927 (patch)
tree1552a31a7c85ef9ba16520a379706680bb1c2525
parent94679e178613ab5b12327829ca54855ac5b1c1c0 (diff)
downloadvyos-cloud-init-7d3f5d750f6111c2716143364ea33486df67c927.tar.gz
vyos-cloud-init-7d3f5d750f6111c2716143364ea33486df67c927.zip
Fix home permissions modified by ssh module (SC-338) (#984)
Fix home permissions modified by ssh module In #956, we updated the file and directory permissions for keys not in the user's home directory. We also unintentionally modified the permissions within the home directory as well. These should not change, and this commit changes that back. LP: #1940233
-rw-r--r--cloudinit/ssh_util.py35
-rw-r--r--tests/integration_tests/modules/test_ssh_keysfile.py132
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)