diff --git a/src/postorius/auth/decorators.py b/src/postorius/auth/decorators.py
index 1b4ea88..7fc369b 100644
--- a/src/postorius/auth/decorators.py
+++ b/src/postorius/auth/decorators.py
@@ -23,6 +23,7 @@
 
 from postorius.models import (Domain, List, Member, MailmanUser,
                               MailmanApiError, Mailman404Error)
+from postorius.utils import user_is_in_list_roster
 
 
 def basic_auth_login(fn):
@@ -56,14 +57,13 @@
             raise PermissionDenied
         if user.is_superuser:
             return fn(*args, **kwargs)
-        if getattr(user, 'is_list_owner', None):
+        if not hasattr(user, 'is_list_owner'):
+            mlist = List.objects.get_or_404(fqdn_listname=list_id)
+            user.is_list_owner = user_is_in_list_roster(user, mlist, "owners")
+        if user.is_list_owner:
             return fn(*args, **kwargs)
-        mlist = List.objects.get_or_404(fqdn_listname=list_id)
-        if user.email not in mlist.owners:
-            raise PermissionDenied
         else:
-            user.is_list_owner = True
-            return fn(*args, **kwargs)
+            raise PermissionDenied
     return wrapper
 
 
@@ -79,22 +79,19 @@
             raise PermissionDenied
         if user.is_superuser:
             return fn(*args, **kwargs)
-        if getattr(user, 'is_list_owner', None):
+        if (not hasattr(user, 'is_list_owner')
+            or not hasattr(user, 'is_list_moderator')):
+            mlist = List.objects.get_or_404(fqdn_listname=list_id)
+            if not hasattr(user, 'is_list_owner'):
+                user.is_list_owner = user_is_in_list_roster(
+                    user, mlist, "owners")
+            if not hasattr(user, 'is_list_moderator'):
+                user.is_list_moderator = user_is_in_list_roster(
+                    user, mlist, "moderators")
+        if user.is_list_owner or user.is_list_moderator:
             return fn(*args, **kwargs)
-        if getattr(user, 'is_list_moderator', None):
-            return fn(*args, **kwargs)
-        mlist = List.objects.get_or_404(fqdn_listname=list_id)
-        if user.email not in mlist.moderators and \
-                user.email not in mlist.owners:
-            raise PermissionDenied
         else:
-            if user.email in mlist.moderators and \
-                    user.email not in mlist.owners:
-                user.is_list_moderator = True
-            else:
-                user.is_list_moderator = True
-                user.is_list_owner = True
-            return fn(*args, **kwargs)
+            raise PermissionDenied
     return wrapper
 
 
diff --git a/src/postorius/utils.py b/src/postorius/utils.py
index 5270543..a34ff63 100644
--- a/src/postorius/utils.py
+++ b/src/postorius/utils.py
@@ -75,3 +75,13 @@
         return
     if user.email in user.other_emails:
         user.other_emails.remove(user.email)
+
+def user_is_in_list_roster(user, mailing_list, roster):
+    if not user.is_authenticated():
+        return False
+    if not hasattr(user, 'other_emails'):
+        set_other_emails(user)
+    addresses = set([user.email]) | set(user.other_emails)
+    if addresses & set(getattr(mailing_list, roster)):
+        return True # At least one address is in the roster
+    return False
diff --git a/src/postorius/views/generic.py b/src/postorius/views/generic.py
index 647e601..896a098 100644
--- a/src/postorius/views/generic.py
+++ b/src/postorius/views/generic.py
@@ -48,14 +48,6 @@
     def _get_list(self, list_id, page):
         return List.objects.get_or_404(fqdn_listname=list_id)
 
-    def _is_in_list_roster(self, user, mailing_list, roster):
-        if not user.is_authenticated():
-            return False
-        addresses = set(user.email) | set(user.other_emails)
-        if addresses & set(getattr(mailing_list, roster)):
-            return True # At least one address is in the roster
-        return False
-
     def dispatch(self, request, *args, **kwargs):
         # get the list object.
         if 'list_id' in kwargs:
@@ -65,9 +57,9 @@
             except MailmanApiError:
                 return utils.render_api_error(request)
             utils.set_other_emails(request.user)
-            request.user.is_list_owner = self._is_in_list_roster(
+            request.user.is_list_owner = utils.user_is_in_list_roster(
                 request.user, self.mailing_list, "owners")
-            request.user.is_list_moderator = self._is_in_list_roster(
+            request.user.is_list_moderator = utils.user_is_in_list_roster(
                 request.user, self.mailing_list, "moderators")
         # set the template
         if 'template' in kwargs: