一除嘹、sudo執(zhí)行命令的流程
將當(dāng)前用戶(hù)切換到超級(jí)用戶(hù)下,或切換到指定的用戶(hù)下叠蝇,
然后以超級(jí)用戶(hù)或其指定切換到的用戶(hù)身份執(zhí)行命令年缎,執(zhí)行完成后,直接退回到當(dāng)前用戶(hù)蜕该。
具體工作過(guò)程如下:
當(dāng)用戶(hù)執(zhí)行sudo時(shí)洲鸠,系統(tǒng)會(huì)主動(dòng)尋找/etc/sudoers文件,判斷該用戶(hù)是否有執(zhí)行sudo的權(quán)限
-->確認(rèn)用戶(hù)具有可執(zhí)行sudo的權(quán)限后淤齐,讓用戶(hù)輸入用戶(hù)自己的密碼確認(rèn)
-->若密碼輸入成功袜匿,則開(kāi)始執(zhí)行sudo后續(xù)的命令
二居灯、不需要輸入密碼的情況
1.root執(zhí)行sudo時(shí)不需要輸入密碼(eudoers文件中有配置root ALL=(ALL) ALL這樣一條規(guī)則)
2.欲切換的身份與執(zhí)行者的身份相同,不需要輸入密碼
3./etc/sudoers文件設(shè)置為允許用戶(hù)在不輸入該用戶(hù)的密碼的情況下使用所有命令
如設(shè)置允許wheel用戶(hù)組中的用戶(hù)在不輸入該用戶(hù)的密碼的情況下使用所有命令
( %wheel ALL=(ALL) NOPASSWD: ALL)
三义锥、/etc/sudoers文件解釋
[root@test ~]# cat /etc/sudoers
Sudoers allows particular users to run various commands as
the root user, without needing the root password.
該文件允許特定用戶(hù)像root用戶(hù)一樣使用各種各樣的命令拌倍,而不需要root用戶(hù)的密碼
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關(guān)命令的示例以供選擇噪径,這些示例都可以被特定用戶(hù)或
## 用戶(hù)組所使用
This file must be edited with the 'visudo' command.
該文件必須使用"visudo"命令編輯
Host Aliases
主機(jī)別名
Groups of machines. You may prefer to use hostnames (perhap using
wildcards for entire domains) or IP addresses instead.
對(duì)于一組服務(wù)器,你可能會(huì)更喜歡使用主機(jī)名(可能是全域名的通配符)
或IP地址代替梗顺,這時(shí)可以配置主機(jī)別名
Host_Alias FILESERVERS = fs1, fs2
Host_Alias MAILSERVERS = smtp, smtp2
User Aliases
用戶(hù)別名
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
這并不很常用车摄,因?yàn)槟憧梢酝ㄟ^(guò)使用組來(lái)代替一組用戶(hù)的別名
User_Alias ADMINS = jsmith, mikem
Command Aliases
These are groups of related commands...
指定一系列相互關(guān)聯(lián)的命令(當(dāng)然可以是一個(gè))的別名吮播,通過(guò)賦予該別名sudo權(quán)限,
可以通過(guò)sudo調(diào)用所有別名包含的命令敞贡,下面是一些示例
Networking
網(wǎng)絡(luò)操作相關(guān)命令別名
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
軟件安裝管理相關(guān)命令別名
Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum
Services
服務(wù)相關(guān)命令別名
Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig
Updating the locate database
本地?cái)?shù)據(jù)庫(kù)升級(jí)命令別名
Cmnd_Alias LOCATE = /usr/sbin/updatedb
Storage
磁盤(pán)操作相關(guān)命令別名
Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount
Delegating permissions
代理權(quán)限相關(guān)命令別名
Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp
Processes
進(jìn)程相關(guān)命令別名
Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall
Drivers
驅(qū)動(dòng)命令別名
Cmnd_Alias DRIVERS = /sbin/modprobe
環(huán)境變量的相關(guān)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).
下面是規(guī)則配置:什么用戶(hù)在哪臺(tái)服務(wù)器上可以執(zhí)行哪些命令(sudoers文件可以在多個(gè)系統(tǒng)上共享)
Syntax:
語(yǔ)法
user MACHINE=COMMANDS
用戶(hù) 登錄的主機(jī)=(可以變換的身份) 可以執(zhí)行的命令
The COMMANDS section may have other options added to it.
命令部分可以附帶一些其它的選項(xiàng)
Allow root to run any commands anywhere
允許root用戶(hù)執(zhí)行任意路徑下的任意命令
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
允許sys中戶(hù)組中的用戶(hù)使用NETWORKING等所有別名中配置的命令
Allows people in group wheel to run all commands
%wheel ALL=(ALL) ALL
允許wheel用戶(hù)組中的用戶(hù)執(zhí)行所有命令
Same thing without a password
允許wheel用戶(hù)組中的用戶(hù)在不輸入該用戶(hù)的密碼的情況下使用所有命令
%wheel ALL=(ALL) NOPASSWD: ALL
Allows members of the users group to mount and unmount the
cdrom as root
允許users用戶(hù)組中的用戶(hù)像root用戶(hù)一樣使用mount、unmount蛔垢、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
允許users用戶(hù)組中的用戶(hù)像root用戶(hù)一樣使用shutdown命令
四迫悠、實(shí)際案例演示
實(shí)例1:讓普通用戶(hù)fieldyang具有/etc/init.d/nagios腳本重啟的權(quán)限,可以在/etc/sudoers添加如下設(shè)置:
[root@test ~]# visudo
fieldyang ALL=NOPASSWD:/etc/init.d/nagios restart
實(shí)例2:讓普通用戶(hù)fieldyang具有所有超級(jí)用戶(hù)的權(quán)限而又不用輸入密碼
[root@test ~]# visudo
fieldyang ALL=(ALL)NOPASSWD:ALL
[fieldyang@test ~]#sudo su -
[fieldyang@test ~]#pwd
/root
實(shí)例3:針對(duì)MySQL數(shù)據(jù)庫(kù)的設(shè)置,讓test組中的test用戶(hù)具備/etc/init.d/mysqld的權(quán)限
######################## mysql ################
[root@test ~]# groupadd test
[root@test ~]# useradd -g test -m -d /home/test -s /bin/bash test
[root@test ~]# passwd test
[root@test ~]# visudo
test ALL=(ALL) NOPASSWD: /etc/init.d/mysqld
test ALL=(ALL) /etc/init.d/mysqld
- start/stop mysql
3.1) start mysql
login test
[root@test ~]# su test
[test@test ~] sudo /etc/init.d/mysqld stop
實(shí)例4:針對(duì)tomcat的設(shè)置艺玲,讓test組中的test用戶(hù)具備tomcat操作的權(quán)限
######################## tomcat ################
[root@test ~]# groupadd test
[root@test ~]# useradd -g test -m -d /home/test -s /bin/bash test
[root@test ~]# passwd test
[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
[root@test ~]# vim /usr/local/tomcat/bin/catalina.sh
### JDK
export JAVA_HOME=/usr/local/jdk
export JRE_HOME=$JAVA_HOME/jre
-
start/stop tomcat
4.1) start tomcat
login test
[root@test ~]# su test
[test@test ~] ss -ntlup | grep java
[test@test ~]$ curl -I http://localhost:80804.2) stop tomcat
login test
[root@test ~]# su test
[test@test ~]$ sudo /usr/local/tomcat/bin/shutdown.sh