diff --git a/rules.mk b/rules.mk
index ac2ea78fea..63fddbb8e7 100644
--- a/rules.mk
+++ b/rules.mk
@@ -61,6 +61,7 @@ CP:=cp -fpR
 INSTALL_BIN:=install -m0755
 INSTALL_DIR:=install -d -m0755
 INSTALL_DATA:=install -m0644
+INSTALL_CONF:=install -m0600
 
 ifneq ($(CONFIG_CCACHE),)
   # FIXME: move this variable to a better location