Centos 普通用户su到root用户提示错误，centosroot

Centos 普通用户su到root用户提示错误，centosroot

一、在CentOS7中普通用户执行SU时，报如下错误：

[test@ecs-1453 ~]$ su -
Password: 
su: Authentication failure

解决方法：

如果root能够正常登陆，就先使用root用户登录系统，再执行操作

1、登陆root账户；
2、执行sudo -i

[root@ecs-1453 ~]# sudo -i

3、执行chmod +s /bin/su

[root@ecs-1453 ~]# chmod +s /bin/su

4、验证

[test@ecs-1453 ~]$ su - root
Password: 
su: Authentication failure
[test@ecs-1453 ~]$ su - root
Password: 
Last login: Tue Feb 27 18:44:34 CST 2018 on pts/0
Last failed login: Tue Feb 27 18:45:42 CST 2018 on pts/1
There was 1 failed login attempt since the last successful login.

二、在centos6中普通用户执行su时，报错如下：

[test@ecs-19cb ~]$ su - root
Password: 
su: incorrect password

解决方法：

如果root能够正常登陆，就先使用root用户登录系统，再执行操作

1、登陆root账户；
2、查看/etc/pam.d/su配置文件，#auth required pam_wheel.so use_uid 这句是否被启用，如果启用了，那么加入了wheel组的用户（usermod -g? wheel 用户id）才能su，否则就会提示密码错误。

[root@ecs-19cb ~]# vim /etc/pam.d/su

#%PAM-1.0
auth            sufficient      pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth           sufficient      pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
#auth            required       pam_wheel.so use_uid
auth            include         system-auth
account         sufficient      pam_succeed_if.so uid = 0 use_uid quiet
account         include         system-auth
password        include         system-auth
session         include         system-auth
session         optional        pam_xauth.so

3、查看文件权限，正确如下

[root@ecs-19cb ~]# ll -a /bin/su?
-rwsr-xr-x. 1 root root 34904 May 11? 2016 /bin/su
[root@ecs-19cb ~]# ll -a /usr/bin/passwd?
-rwsr-xr-x. 1 root root 30768 Nov 24? 2015 /usr/bin/passwd

4、验证

[test@ecs-19cb ~]$ su - root
Password:?
su: incorrect password
[test@ecs-19cb ~]$ su - root
Password:?
[root@ecs-19cb ~]#