From 2d4855508c89ea70933f776a2e5b967bb17f8249 Mon Sep 17 00:00:00 2001
From: Jonathan Leroy <jonathan@inikup.com>
Date: Sun, 1 Nov 2020 23:58:40 +0100
Subject: [PATCH] Check that an alias zone source is not an alias zone

---
 octodns/manager.py                | 16 ++++++++++++++++
 tests/config/alias-zone-loop.yaml | 21 +++++++++++++++++++++
 tests/test_octodns_manager.py     | 17 ++++++++++++++++-
 3 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 tests/config/alias-zone-loop.yaml

diff --git a/octodns/manager.py b/octodns/manager.py
index cfc9735..5f4af55 100644
--- a/octodns/manager.py
+++ b/octodns/manager.py
@@ -280,6 +280,7 @@ class Manager(object):
             self.log.info('sync:   zone=%s', zone_name)
             if 'alias' in config:
                 source_zone = config['alias']
+
                 # Check that the source zone is defined.
                 if source_zone not in self.config['zones']:
                     self.log.error('Invalid alias zone {}, target {} does '
@@ -288,6 +289,14 @@ class Manager(object):
                                            'source zone {} does not exist'
                                            .format(zone_name, source_zone))
 
+                # Check that the source zone is not an alias zone itself.
+                if 'alias' in self.config['zones'][source_zone]:
+                    self.log.error('Invalid alias zone {}, target {} is an '
+                                   'alias zone'.format(zone_name, source_zone))
+                    raise ManagerException('Invalid alias zone {}: source '
+                                           'zone {} is an alias zone'
+                                           .format(zone_name, source_zone))
+
                 aliased_zones[zone_name] = source_zone
                 continue
 
@@ -473,6 +482,13 @@ class Manager(object):
                     raise ManagerException('Invalid alias zone {}: '
                                            'source zone {} does not exist'
                                            .format(zone_name, source_zone))
+
+                if 'alias' in self.config['zones'][source_zone]:
+                    self.log.exception('Invalid alias zone')
+                    raise ManagerException('Invalid alias zone {}: '
+                                           'source zone {} is an alias zone'
+                                           .format(zone_name, source_zone))
+
                 # this is just here to satisfy coverage, see
                 # https://github.com/nedbat/coveragepy/issues/198
                 source_zone = source_zone
diff --git a/tests/config/alias-zone-loop.yaml b/tests/config/alias-zone-loop.yaml
new file mode 100644
index 0000000..df8b53f
--- /dev/null
+++ b/tests/config/alias-zone-loop.yaml
@@ -0,0 +1,21 @@
+manager:
+  max_workers: 2
+providers:
+  in:
+    class: octodns.provider.yaml.YamlProvider
+    directory: tests/config
+  dump:
+    class: octodns.provider.yaml.YamlProvider
+    directory: env/YAML_TMP_DIR
+zones:
+  unit.tests.:
+    sources:
+      - in
+    targets:
+      - dump
+  
+  alias.tests.:
+    alias: unit.tests.
+
+  alias-loop.tests.:
+    alias: alias.tests.
diff --git a/tests/test_octodns_manager.py b/tests/test_octodns_manager.py
index 6affa17..dc047e8 100644
--- a/tests/test_octodns_manager.py
+++ b/tests/test_octodns_manager.py
@@ -183,6 +183,14 @@ class TestManager(TestCase):
                               'does-not-exists.tests. does not exist',
                               text_type(ctx.exception))
 
+            # Alias zone that points to another alias zone.
+            with self.assertRaises(ManagerException) as ctx:
+                tc = Manager(get_config_filename('alias-zone-loop.yaml')) \
+                    .sync()
+            self.assertEquals('Invalid alias zone alias-loop.tests.: source '
+                              'zone alias.tests. is an alias zone',
+                              text_type(ctx.exception))
+
     def test_compare(self):
         with TemporaryDirectory() as tmpdir:
             environ['YAML_TMP_DIR'] = tmpdir.dirname
@@ -306,7 +314,14 @@ class TestManager(TestCase):
         with self.assertRaises(ManagerException) as ctx:
             Manager(get_config_filename('unknown-source-zone.yaml')) \
                 .validate_configs()
-        self.assertTrue('Invalid alias zone' in
+        self.assertTrue('does not exist' in
+                        text_type(ctx.exception))
+
+        # Alias zone that points to another alias zone.
+        with self.assertRaises(ManagerException) as ctx:
+            Manager(get_config_filename('alias-zone-loop.yaml')) \
+                .validate_configs()
+        self.assertTrue('is an alias zone' in
                         text_type(ctx.exception))
 
         # Valid config file using an alias zone.