yum安装的proftpd无法登录系统用户

默认安装的proftpd 的 pam_stack.so 模块文件不存在
我经过参考 http://cosmicb.no/2014/05/09/proftpd-pam-unable-to-dlopenlib64securitypam_stack-so-in-centos-6-5/
修改 /etc/pam.d/proftpd 为
auth required pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed
auth required pam_shells.so
auth include system-auth
account include system-auth
session required pam_loginuid.so