Don't allow Domain name matching production domain to be created

readthedocs/projects/forms.py

@@ -634,6 +634,19 @@ def clean_domain(self):
             domain_string = parsed.netloc
         else:
             domain_string = parsed.path
+
+        if (
+            settings.PRODUCTION_DOMAIN and
+            settings.PRODUCTION_DOMAIN in domain_string
+        ):
+            raise forms.ValidationError('Enter a valid domain name.')
+
+        if (
+            settings.PUBLIC_DOMAIN and
+            settings.PUBLIC_DOMAIN in domain_string
+        ):
+            raise forms.ValidationError('Enter a valid domain name.')
+
         return domain_string
 
     def clean_canonical(self):

readthedocs/rtd_tests/tests/test_domains.py

@@ -2,7 +2,8 @@
 
 import json
 
-from django.test import TestCase
+from django.conf import settings
+from django.test import TestCase, override_settings
 from django_dynamic_fixture import get
 
 from readthedocs.projects.forms import DomainForm
@@ -53,6 +54,39 @@ def test_https(self):
         )
         self.assertFalse(form.is_valid())
 
+    def test_production_domain_not_allowed(self):
+        """Make sure user can not enter production domain name."""
+        form = DomainForm(
+            {'domain': settings.PRODUCTION_DOMAIN},
+            project=self.project,
+        )
+        self.assertFalse(form.is_valid())
+        self.assertEqual(form.errors['domain'][0], 'Enter a valid domain name.')
+
+        form2 = DomainForm(
+            {'domain': 'test.' + settings.PRODUCTION_DOMAIN},
+            project=self.project,
+        )
+        self.assertFalse(form2.is_valid())
+        self.assertEqual(form2.errors['domain'][0], 'Enter a valid domain name.')
+
+    @override_settings(PUBLIC_DOMAIN='readthedocs.io')
+    def test_public_domain_not_allowed(self):
+        """Make sure user can not enter public domain name."""
+        form = DomainForm(
+            {'domain': settings.PUBLIC_DOMAIN},
+            project=self.project,
+        )
+        self.assertFalse(form.is_valid())
+        self.assertEqual(form.errors['domain'][0], 'Enter a valid domain name.')
+
+        form2 = DomainForm(
+            {'domain': 'docs.' + settings.PUBLIC_DOMAIN},
+            project=self.project,
+        )
+        self.assertFalse(form2.is_valid())
+        self.assertEqual(form2.errors['domain'][0], 'Enter a valid domain name.')
+
     def test_canonical_change(self):
         """Make sure canonical can be properly changed."""
         form = DomainForm(