1. 解决问题

问题：

sudo: /etc/sudoers is world writable
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin

解决这个问题，只需要在root超级用户下，修改这个文件的权限即可

[root@centos swpu]# chmod 440 /etc/sudoers

2.设置普通用户的sudo权限

在root用户下，编辑文件，并在最上面添加两句话

[root@centos swpu]# vi /etc/sudoers

swpu ALL=(root)NOPASSWD:ALL
senior ALL=(root)NOPASSWD:ALL
## Sudoers allows particular users to run various commands as
## the root user, without needing the root password.
##
## Examples are provided at the bottom of the file for collections
## of related commands, which can then be delegated out to particular
## users or groups.
##
## This file must be edited with the 'visudo' command.

## Host Aliases
## Groups of machines. You may prefer to use hostnames (perhaps using
## wildcards for entire domains) or IP addresses instead.
# Host_Alias     FILESERVERS = fs1, fs2
# Host_Alias     MAILSERVERS = smtp, smtp2

## User Aliases
## These aren't often necessary, as you can use regular groups
## (ie, from files, LDAP, NIS, etc) in this file - just use %groupname
## rather than USERALIAS
# User_Alias ADMINS = jsmith, mikem


## Command Aliases
## These are groups of related commands...

## Networking
# Cmnd_Alias NETWORKING = /sbin/route, /sbin/ifconfig, /bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptables, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool

## Installation and management of software
# Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum

## Services
Type  :quit<Enter>  to exit Vim 

然后保存文件，如果这个文件现在是只是可写文件，必须先更改权限为可读可写后再添加两句话，最后再保存

接下来尝试普通用户的sudo权限，就会遇到本文中出现的问题，按上面方法解决就好。最后，就设置好了普通用户的sudo权限！！！可以完成如下操作了

[root@centos swpu]# su - swpu
[swpu@centos ~]$ more /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

## ip地址与主机名之间的映射
192.168.186.29  centos.liujie.com  centos



[swpu@centos ~]$ vi /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

## ip地址与主机名之间的映射
192.168.186.29  centos.liujie.com  centos



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"/etc/hosts" [readonly] 8L, 243C      

可以看出普通用户对/etc/hosts只有可读权限，使用普通用户sudo权限

[swpu@centos ~]$ sudo vi /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

## ip地址与主机名之间的映射
192.168.186.29  centos.liujie.com  centos



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Type  :quit<Enter>  to exit Vim

发现对这个文件具有可读可写权限！！！

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