Allow password policy minlength to be removed like other values

This is a side-effect of adding the libpwquality options. It
imposes its own hardcoded minimum password length so some care
was needed to ensure that it isn't set too low.

So if there are no libpwquality options used then it's fine to
have no minlength in the policy.

Fixes: https://pagure.io/freeipa/issue/9297

Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>

ipaserver/plugins/pwpolicy.py

@@ -462,6 +462,7 @@ def has_pwquality_set(entry):
             return False
 
         has_pwquality_value = False
+        min_length = 0
         if not add:
             if len(keys) > 0:
                 existing_entry = self.api.Command.pwpolicy_show(
@@ -470,14 +471,15 @@ def has_pwquality_set(entry):
                 existing_entry = self.api.Command.pwpolicy_show(
                     all=True,)['result']
             existing_entry.update(entry_attrs)
-            min_length = int(get_val(existing_entry, 'krbpwdminlength'))
-
+            if existing_entry.get('krbpwdminlength'):
+                min_length = int(get_val(existing_entry, 'krbpwdminlength'))
             has_pwquality_value = has_pwquality_set(existing_entry)
         else:
-            min_length = int(get_val(entry_attrs, 'krbpwdminlength'))
+            if entry_attrs.get('krbpwdminlength'):
+                min_length = int(get_val(entry_attrs, 'krbpwdminlength'))
             has_pwquality_value = has_pwquality_set(entry_attrs)
 
-        if min_length and min_length < 6 and has_pwquality_value:
+        if min_length < 6 and has_pwquality_value:
             raise errors.ValidationError(
                 name='minlength',
                 error=_('Minimum length must be >= 6 if maxrepeat, '

ipatests/test_integration/test_pwpolicy.py

@@ -36,7 +36,9 @@ def install(cls, mh):
         cls.master.run_command(['ipa', 'group-add-member', POLICY,
                                 '--users', USER])
         cls.master.run_command(['ipa', 'pwpolicy-add', POLICY,
-                                '--priority', '1', '--gracelimit', '-1'])
+                                '--priority', '1',
+                                '--gracelimit', '-1',
+                                '--minlength', '6'])
         cls.master.run_command(['ipa', 'passwd', USER],
                                stdin_text='{password}\n{password}\n'.format(
                                password=PASSWORD
@@ -92,6 +94,12 @@ def clean_pwpolicy(self):
              "--minlength", "0",
              "--minclasses", "0",],
         )
+        # minlength => 6 is required for any of the libpwquality settings
+        self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--minlength", "6"],
+            raiseonerr=False,
+        )
 
     @pytest.fixture
     def reset_pwpolicy(self):
@@ -212,6 +220,7 @@ def test_minclasses(self, reset_pwpolicy):
             assert 'Password is too simple' in \
                 result.stdout_text
 
+        self.reset_password(self.master)
         # test with valid password
         for valid in ('Passw0rd', 'password1!', 'Password!'):
             self.kinit_as_user(self.master, PASSWORD, valid)
@@ -252,6 +261,40 @@ def test_minlength_mod(self, reset_pwpolicy):
             assert result.returncode != 0
             assert 'minlength' in result.stderr_text
 
+    def test_minlength_empty(self, reset_pwpolicy):
+        """Test that the pwpolicy minlength can be blank
+        """
+        # Ensure it is set to a non-zero value to avoid EmptyModlist
+        self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--minlength", "10",]
+        )
+        # Enable one of the libpwquality options, removing minlength
+        # should fail.
+        self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--maxrepeat", "4",]
+        )
+        result = self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--minlength", "",], raiseonerr=False
+        )
+        assert result.returncode != 0
+
+        # Remove the blocking value
+        self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--maxrepeat", "",]
+        )
+
+        # Now erase it
+        result = self.master.run_command(
+            ["ipa", "pwpolicy-mod", POLICY,
+             "--minlength", "",]
+        )
+        assert result.returncode == 0
+        assert 'minlength' not in result.stderr_text
+
     def test_minlength_add(self):
         """Test that adding a new policy with minlength is caught.
         """