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[操作系统]Linux sudo


介绍

本篇文章主要介绍sudo配置和用法,为了给某个用户控制权限比如执行某个命令或者关机操作等,服务器管理员通常会给这个用户配置sudo,接下来就来详细介绍具体的配置方法。

环境:centos6.7

 

结构说明

可以通过编辑文件/etc/sudoers来配置,通常使用visudo命令来进行修改,因为如果你修改的格式不符合它会进行提示。接下来就通过一个格式来了解它

<user> <host> = [<operator user> [<par>]] <command list>

chenmh localhost = (root)  NOPASSWD: /bin/mkdir test

<user>:指的是具体的用户或者用户别名,如果使用%user指的是用户组。

<host>:指的是具体的host(可以是机器名也可以是ip)或者是host别名,ALL代表所有的host。

<operator user>:可选,指定可以用调用哪个用户的来执行,ALL代表调用root用户来执行。这里要说明一下root用户的权限代表什么意思,比如一个目录的所有者是root,那么必须具备root用户的权限才能执行相关操作,比如上面的chenmh用户如果它配置的是其它用户比如它自己,那么它在root所有者的目录下面是没权限执行操作的。同样如果这里配置的是哪个用户那么比如mkdir创建的文件夹就的所有者就是哪个用户。默认不指定代表使用ALL

<par>:可选,指定参数,通常使用NOPASSWD(代表该用户在执行sudo的时候不需要再输入自己的密码)。

<command list>:指定的具体命令或者是命令别名或者是ALL,ALL代表所有权限。

说明: [<operator user> [<par>]]这两个选项是可以选的可以不指定,如果不指定默认是调用root用户执行,但是使用sudo必须输入用户自己的密码

配置文件

接下来详细来看看它的配置文件,它的配置文件以及很详细的告诉了我们该怎样使用,在前面一部分是示例怎样将一组权限创建组别名,注意别名需要大写,

## 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.
##可以将多个host配置成一个host别名## Host Aliases ## Groups of machines. You may prefer to use hostnames (perhaps using ## wildcards for entire domains) or IP addresses instead.Host_Alias FILESERVERS = 192.168.137.40,192.168.137.30# Host_Alias MAILSERVERS = smtp, smtp2
##将多个user配置成一个user别名## 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 USERALIASUser_Alias ADMINS = chenmh###接下来是命令别名,就是将一组命令放在一起,这样可以简便配置## 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# Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig## Updating the locate database# Cmnd_Alias LOCATE = /usr/bin/updatedb## Storage# Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount## Delegating permissions# Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp ## Processes# Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall## Drivers# Cmnd_Alias DRIVERS = /sbin/modprobe
###这个是我自己配置的命令别名,将mkdir和rm命令配置在一起分配给某个用户##userdefinCmnd_Alias OTHERS = /bin/mkdir, /bin/rm# 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## Refuse to run if unable to disable echo on the tty. This setting should also be# changed in order to be able to use sudo without a tty. See requiretty above.#Defaults !visiblepw## Preserving HOME has security implications since many programs# use it when searching for configuration files. Note that HOME# is already set when the the env_reset option is enabled, so# this option is only effective for configurations where either# env_reset is disabled or HOME is present in the env_keep list.#Defaults always_set_homeDefaults env_resetDefaults env_keep = "COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS"Defaults env_keep += "MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE"Defaults env_keep += "LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES"Defaults env_keep += "LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE"Defaults env_keep += "LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY"## Adding HOME to env_keep may enable a user to run unrestricted# commands via sudo.## Defaults env_keep += "HOME"Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin## Next comes the main part: which users can run what software on ## which machines (the sudoers file can be shared between multiple## systems).## Syntax:#### user MACHINE=COMMANDS#### The COMMANDS section may have other options added to it.#### Allow root to run any commands anywhere 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###sys这个组中的用户可以执行相关的命令组的权限,多个命令组用逗号分隔## Allows people in group wheel to run all commands# %wheel ALL=(ALL) ALL## Same thing without a password# %wheel ALL=(ALL) NOPASSWD: ALL## Allows members of the users group to mount and unmount the ## cdrom as root# %users ALL=/sbin/mount /mnt/cdrom, /sbin/umount /mnt/cdrom###users组的用户可以执行挂载和卸载/mnt/cdrom目录的权限## Allows members of the users group to shutdown this system# %users localhost=/sbin/shutdown -h now###users组的用户可以执行关机命令## Read drop-in files from /etc/sudoers.d (the # here does not mean a comment)#includedir /etc/sudoers.d

 

案例

1.用户别名组中的用户可以在FILESERVERS这组host里面调用root用户执行OTHERS命令组的权限,多个命令组用逗号分隔

ADMINS FILESERVERS=(ALL)  NOPASSWD:OTHERS

2.用户chenmh这个用户可以在本机以调用root用户来执行所有的命令

chenmh localhost=(root) NOPASSWORD:ALL

3.用户chenmh可以调用root用户创建目录test,也只能创建test目录

chenmh ALL=(ALL)  NOPASSWD: /bin/mkdir test

4.dev组的用户可以执行关机shutdown命令

%dev ALL=(ALL)  NOPASSWD:/sbin/shutdown


快捷操作 

 1.查看当前用户具备的sudo权限

sudo -l
User chenmh may run the following commands on this host:  (root) NOPASSWD: /bin/mkdir, /bin/rm

总结

配置sudo记得使用visudo命令,如果配置错误了保存的时候它会有提示。 

 

 

 

备注:

    作者:pursuer.chen

    博客:http://www.cnblogs.com/chenmh

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