diff --git a/Allura/allura/lib/plugin.py b/Allura/allura/lib/plugin.py
index ea66b60..006a8e0 100644
--- a/Allura/allura/lib/plugin.py
+++ b/Allura/allura/lib/plugin.py
@@ -562,7 +562,10 @@
         if ldap is None:
             raise Exception('The python-ldap package needs to be installed.  Run `pip install python-ldap` in your allura environment.')
         from allura import model as M
-        username = self.request.params['username']
+        try:
+            username = str(self.request.params['username'])
+        except UnicodeEncodeError:
+            raise exc.HTTPBadRequest('Unicode is not allowed in usernames')
         if not self._validate_password(username, self.request.params['password']):
             raise exc.HTTPUnauthorized()
         user = M.User.query.get(username=username)
@@ -586,6 +589,7 @@
 
     def _validate_password(self, username, password):
         '''by username'''
+        password = h.really_unicode(password).encode('utf-8')
         try:
             ldap_user = ldap_user_dn(username)
         except ValueError:
diff --git a/Allura/allura/lib/widgets/auth_widgets.py b/Allura/allura/lib/widgets/auth_widgets.py
index 33444f9..22f4429 100644
--- a/Allura/allura/lib/widgets/auth_widgets.py
+++ b/Allura/allura/lib/widgets/auth_widgets.py
@@ -66,6 +66,12 @@
                 dict(username=value['username'], rememberme=value.get('rememberme'),
                      return_to=value.get('return_to')),
                 None)
+        except exc.HTTPBadRequest as e:
+            raise Invalid(
+                e.message,
+                dict(username=value['username'], rememberme=value.get('rememberme'),
+                     return_to=value.get('return_to')),
+                None)
         return value