sudo配置文件/etc/sudoers详解及实战用法

水深无声 2022-08-22 15:11 166阅读 0赞

**一、sudo执行命令的流程**  
将当前用户切换到超级用户下，或切换到指定的用户下，  
然后以超级用户或其指定切换到的用户身份执行命令，执行完成后，直接退回到当前用户。  
具体工作过程如下：  
当用户执行sudo时，系统会主动寻找/etc/sudoers文件，判断该用户是否有执行sudo的权限  
\-->确认用户具有可执行sudo的权限后，让用户输入用户自己的密码确认  
\-->若密码输入成功，则开始执行sudo后续的命令

**二、不需要输入密码的情况**  
1.root执行sudo时不需要输入密码(eudoers文件中有配置root ALL=(ALL) ALL这样一条规则)  
2.欲切换的身份与执行者的身份相同，不需要输入密码  
3./etc/sudoers文件设置为允许用户在不输入该用户的密码的情况下使用所有命令  
如设置允许wheel用户组中的用户在不输入该用户的密码的情况下使用所有命令  
（ %wheel        ALL=(ALL)       NOPASSWD: ALL）

**三、/etc/sudoers文件解释**  
\[root@test ~\]\# cat /etc/sudoers  
\#\# Sudoers allows particular users to run various commands as  
\#\# the root user, without needing the root password.  
\#\#该文件允许特定用户像root用户一样使用各种各样的命令，而不需要root用户的密码  
\#\#  
\#\# 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.  
\#\# 在文件的底部提供了很多相关命令的示例以供选择，这些示例都可以被特定用户或   
\#\# \#\# 用户组所使用   
\#\# This file must be edited with the 'visudo' command.  
\#\# 该文件必须使用"visudo"命令编辑

\#\# Host Aliases  
\#主机别名  
\#\# Groups of machines. You may prefer to use hostnames (perhap using  
\#\# wildcards for entire domains) or IP addresses instead.  
\#\# 对于一组服务器，你可能会更喜欢使用主机名（可能是全域名的通配符）  
\#\# 或IP地址代替，这时可以配置主机别名  
   
\# Host\_Alias     FILESERVERS = fs1, fs2  
\# Host\_Alias     MAILSERVERS = smtp, smtp2

\#\# User Aliases  
\#用户别名  
\#\# 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  
\#\# 这并不很常用，因为你可以通过使用组来代替一组用户的别名   
\# User\_Alias ADMINS = jsmith, mikem

\#\# Command Aliases  
\#\# These are groups of related commands...  
\#\# 指定一系列相互关联的命令（当然可以是一个）的别名，通过赋予该别名sudo权限，   
\#\# 可以通过sudo调用所有别名包含的命令，下面是一些示例

\#\# Networking  
\#网络操作相关命令别名   
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  
\#软件安装管理相关命令别名   
Cmnd\_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum

\#\# Services  
\#服务相关命令别名  
Cmnd\_Alias SERVICES = /sbin/service, /sbin/chkconfig

\#\# Updating the locate database  
\#本地数据库升级命令别名   
Cmnd\_Alias LOCATE = /usr/sbin/updatedb

\#\# Storage  
\#磁盘操作相关命令别名  
Cmnd\_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount

\#\# Delegating permissions  
\#代理权限相关命令别名  
Cmnd\_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp

\#\# Processes  
\#进程相关命令别名  
Cmnd\_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall

\#\# Drivers  
\#驱动命令别名  
Cmnd\_Alias DRIVERS = /sbin/modprobe  
\#环境变量的相关配置  
\# Defaults specification

\#  
\# Disable "ssh hostname sudo <cmd>", because it will show the password in clear.  
\#         You have to run "ssh -t hostname sudo <cmd>".  
\#  
Defaults    requiretty

Defaults    env\_reset  
Defaults    env\_keep = "COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR \\  
                        LS\_COLORS MAIL PS1 PS2 QTDIR USERNAME \\  
                        LANG LC\_ADDRESS LC\_CTYPE LC\_COLLATE LC\_IDENTIFICATION \\  
                        LC\_MEASUREMENT LC\_MESSAGES LC\_MONETARY LC\_NAME LC\_NUMERIC \\  
                        LC\_PAPER LC\_TELEPHONE LC\_TIME LC\_ALL LANGUAGE LINGUAS \\  
                        \_XKB\_CHARSET XAUTHORITY"

\#\# Next comes the main part: which users can run what software on  
\#\# which machines (the sudoers file can be shared between multiple  
\#\# systems).  
\#\# 下面是规则配置：什么用户在哪台服务器上可以执行哪些命令（sudoers文件可以在多个系统上共享）  
\#\# Syntax:  
\#\#语法  
\#\#      user    MACHINE=COMMANDS  
\#\#  用户 登录的主机=（可以变换的身份） 可以执行的命令   
\#\#  
\#\# The COMMANDS section may have other options added to it.  
\#\# 命令部分可以附带一些其它的选项   
\#\#  
\#\# Allow root to run any commands anywhere  
\#\# 允许root用户执行任意路径下的任意命令  
root    ALL=(ALL)       ALL

\#\# Allows members of the 'sys' group to run networking, software,  
\#\# service management apps and more.  
\# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS  
\#\# 允许sys中户组中的用户使用NETWORKING等所有别名中配置的命令  
   
\#\# Allows people in group wheel to run all commands  
\# %wheel        ALL=(ALL)       ALL  
\#\# 允许wheel用户组中的用户执行所有命令   
\#\# Same thing without a password  
\#\# 允许wheel用户组中的用户在不输入该用户的密码的情况下使用所有命令  
\# %wheel        ALL=(ALL)       NOPASSWD: ALL

\#\# Allows members of the users group to mount and unmount the  
\#\# cdrom as root  
\#\# 允许users用户组中的用户像root用户一样使用mount、unmount、chrom命令  
\# %users  ALL=/sbin/mount /mnt/cdrom, /sbin/umount /mnt/cdrom

\#\# Allows members of the users group to shutdown this system  
\# %users  localhost=/sbin/shutdown -h now  
\#\# 允许users用户组中的用户像root用户一样使用shutdown命令

**四、实际案例演示**

实例1：让普通用户fieldyang具有/etc/init.d/nagios脚本重启的权限，可以在/etc/sudoers添加如下设置：

\[root@test ~\]\# visudo

fieldyang ALL=NOPASSWD:/etc/init.d/nagios restart

实例2：让普通用户fieldyang具有所有超级用户的权限而又不用输入密码

\[root@test ~\]\# visudo  
fieldyang ALL=（ALL)NOPASSWD:ALL  
\[fieldyang@test ~\]\#sudo su -  
\[fieldyang@test ~\]\#pwd  
/root

实例3：针对MySQL数据库的设置，让test组中的test用户具备/etc/init.d/mysqld的权限  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# mysql \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
1.  
\[root@test ~\]\# groupadd test  
\[root@test ~\]\# useradd -g test -m -d /home/test -s /bin/bash test  
\[root@test ~\]\# passwd test  
2.  
\[root@test ~\]\# visudo  
\# test ALL=(ALL) NOPASSWD: /etc/init.d/mysqld  
test ALL=(ALL)  /etc/init.d/mysqld  
3. start/stop mysql  
    3.1) start mysql  
        login test  
\[root@test ~\]\# su test  
\[test@test ~\]$ sudo /etc/init.d/mysqld start  
    3.2) stop mysql  
        login test  
\[root@test ~\]\# su test  
\[test@test ~\]$ sudo /etc/init.d/mysqld stop

实例4：针对tomcat的设置，让test组中的test用户具备tomcat操作的权限  
\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# tomcat \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  
1.  
\[root@test ~\]\# groupadd test  
\[root@test ~\]\# useradd -g test -m -d /home/test -s /bin/bash test  
\[root@test ~\]\# passwd test  
2.  
\[root@test ~\]\# visudo  
    \# test ALL=(ALL)  /usr/local/tomcat/bin/shutdown.sh,/usr/local/tomcat/bin/startup.sh  
    test ALL=(ALL) NOPASSWD: /usr/local/tomcat/bin/shutdown.sh,/usr/local/tomcat/bin/startup.sh  
3.  
\[root@test ~\]\# vim /usr/local/tomcat/bin/catalina.sh  
    \#\#\# JDK  
    export JAVA\_HOME=/usr/local/jdk  
    export JRE\_HOME=$JAVA\_HOME/jre  
4. start/stop tomcat  
    4.1) start tomcat  
        login test  
\[root@test ~\]\# su test    
\[test@test ~\]$ sudo /usr/local/tomcat/bin/startup.sh  
\[test@test ~\]$ ss -ntlup | grep java  
\[test@test ~\]$ curl -I [http://localhost:8080][http_localhost_8080]

4.2) stop tomcat  
        login test  
\[root@test ~\]\# su test   
\[test@test ~\]$ sudo /usr/local/tomcat/bin/shutdown.sh

[http_localhost_8080]: http://localhost:8080