ssh_utils.py: ignore when sshd_config options are not key/value pairs (#1007)

As specified in #LP 1845552,
In cloudinit/ssh_util.py, in parse_ssh_config_lines(), we attempt to
parse each line of sshd_config. This function expects each line to
be one of the following forms:

    \# comment
    key value
    key=value

However, options like DenyGroups and DenyUsers are specified to
*optionally* accepts values in sshd_config.
Cloud-init should comply to this and skip the option if a value
is not provided.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/unittests/test_sshutil.py b/tests/unittests/test_sshutil.py
index a66788bf..08e20050 100644
--- a/tests/unittests/test_sshutil.py
+++ b/tests/unittests/test_sshutil.py
@@ -525,6 +525,14 @@ class TestUpdateSshConfigLines(test_helpers.CiTestCase):
         self.assertEqual([self.pwauth], result)
         self.check_line(lines[-1], self.pwauth, "no")
 
+    def test_option_without_value(self):
+        """Implementation only accepts key-value pairs."""
+        extended_exlines = self.exlines.copy()
+        denyusers_opt = "DenyUsers"
+        extended_exlines.append(denyusers_opt)
+        lines = ssh_util.parse_ssh_config_lines(list(extended_exlines))
+        self.assertNotIn(denyusers_opt, str(lines))
+
     def test_single_option_updated(self):
         """A single update should have change made and line updated."""
         opt, val = ("UsePAM", "no")