Fix Respect can_read_model permission in DjangoModelPermissions

FIXES: encode#6324

rest_framework/permissions.py

@@ -175,9 +175,9 @@ class DjangoModelPermissions(BasePermission):
     # Override this if you need to also provide 'view' permissions,
     # or if you want to provide custom permission codes.
     perms_map = {
-        'GET': [],
+        'GET': ['%(app_label)s.view_%(model_name)s'],
         'OPTIONS': [],
-        'HEAD': [],
+        'HEAD': ['%(app_label)s.view_%(model_name)s'],
         'POST': ['%(app_label)s.add_%(model_name)s'],
         'PUT': ['%(app_label)s.change_%(model_name)s'],
         'PATCH': ['%(app_label)s.change_%(model_name)s'],
@@ -228,8 +228,16 @@ def has_permission(self, request, view):
 
         queryset = self._queryset(view)
         perms = self.get_required_permissions(request.method, queryset.model)
+        change_perm = self.get_required_permissions('PUT', queryset.model)
+
+        user = request.user
+        if request.method == 'GET':
+           if user.has_perms(perms) or user.has_perms(change_perm):
+              return True
+           else:
+              return False
 
-        return request.user.has_perms(perms)
+        return user.has_perms(perms)
 
 
 class DjangoModelPermissionsOrAnonReadOnly(DjangoModelPermissions):