luci/applications/luci-app-samba4/root/usr/share/rpcd/acl.d/luci-app-samba4.json

{
	"luci-app-samba4": {
		"description": "Grant access to LuCI app samba4",
		"read": {
			"file": {
				"/etc/samba/smb.conf.template": [ "read" ],
				"/usr/sbin/smbd": [ "exec" ]
			},
			"uci": [ "samba4" ]
		},
		"write": {
			"file": {
				"/etc/samba/smb.conf.template": [ "write" ]
			},
			"uci": [ "samba4" ]
		}
	}
}