diff --git a/rhodecode/model/repo_permission.py b/rhodecode/model/repo_permission.py
--- a/rhodecode/model/repo_permission.py
+++ b/rhodecode/model/repo_permission.py
@@ -26,14 +26,29 @@
 
 import logging
 from rhodecode.model import BaseModel
-from rhodecode.model.db import UserRepoToPerm, UsersGroupRepoToPerm, Permission
+from rhodecode.model.db import UserRepoToPerm, UsersGroupRepoToPerm, Permission,\
+    User, Repository
 
 log = logging.getLogger(__name__)
 
 
 class RepositoryPermissionModel(BaseModel):
 
+    def __get_user(self, user):
+        return self._get_instance(User, user, callback=User.get_by_username)
+
+    def __get_repo(self, repository):
+        return self._get_instance(Repository, repository,
+                                  callback=Repository.get_by_repo_name)
+
+    def __get_perm(self, permission):
+        return self._get_instance(Permission, permission,
+                                  callback=Permission.get_by_key)
+
     def get_user_permission(self, repository, user):
+        repository = self.__get_repo(repository)
+        user = self.__get_user(user)
+
         return UserRepoToPerm.query() \
                 .filter(UserRepoToPerm.user == user) \
                 .filter(UserRepoToPerm.repository == repository) \