Linux基础day14

[root@oldboyedu ~]# chage -l oldboy
Last password change                    : Oct 07, 2020
Password expires                    : never
Password inactive                   : never
Account expires                     : never
Minimum number of days between password change      : 0
Maximum number of days between password change      : 99999
Number of days of warning before password expires   : 7
[root@oldboyedu ~]# chage -E "2020/10/1" oldboy
[root@oldboyedu ~]# chage -l oldboy
Last password change                    : Oct 07, 2020
Password expires                    : never
Password inactive                   : never
Account expires                     : Oct 01, 2020
Minimum number of days between password change      : 0
Maximum number of days between password change      : 99999
Number of days of warning before password expires   : 7


范例14-17：创建新用户range,要求该用户7天内不能更改密码，
60天以后必须修改密码，过期前10天通知用户，过期后30天后禁止用户登录。
chage -m7 -M60 -W10 -I30 oldboy
联系英文：
Options:
  -d, --lastday LAST_DAY        set date of last password change to LAST_DAY
  -E, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
  -h, --help                    display this help message and exit
  -I, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -l, --list                    show account aging information
  -m, --mindays MIN_DAYS        set minimum number of days before password
                                change to MIN_DAYS
  -M, --maxdays MAX_DAYS        set maximim number of days before password
                                change to MAX_DAYS
  -R, --root CHROOT_DIR         directory to chroot into
  -W, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS

  
[root@oldboyedu ~]# chage -l oldboy
Last password change                    : Oct 07, 2020
Password expires                    : never
Password inactive                   : never
Account expires                     : Oct 01, 2020
Minimum number of days between password change      : 0
Maximum number of days between password change      : 99999
Number of days of warning before password expires   : 7
You have new mail in /var/spool/mail/root
[root@oldboyedu ~]# chage -m7 -M60 -W10 -I30 oldboy
[root@oldboyedu ~]# chage -l oldboy
Last password change                    : Oct 07, 2020
Password expires                    : Dec 06, 2020
Password inactive                   : Jan 05, 2021
Account expires                     : Oct 01, 2020
Minimum number of days between password change      : 7
Maximum number of days between password change      : 60
Number of days of warning before password expires   : 10

passwd -n70 -x600 -w100 -i300 oldboy

[root@oldboyedu ~]# passwd -n70 -x600 -w100 -i300 oldboy
Adjusting aging data for user oldboy.
passwd: Success
You have new mail in /var/spool/mail/root
[root@oldboyedu ~]# chage -l oldboy
Last password change                    : Oct 07, 2020
Password expires                    : May 30, 2022
Password inactive                   : Mar 26, 2023
Account expires                     : Oct 01, 2020
Minimum number of days between password change      : 70
Maximum number of days between password change      : 600
Number of days of warning before password expires   : 100



-n, --minimum DAYS
              This  will  set  the  minimum password lifetime, in days, if the user's account supports password life‐
              times.  Available to root only.

-x, --maximum DAYS
              This will set the maximum password lifetime, in days, if the user's  account  supports  password  life‐
              times.  Available to root only.

-w, --warning DAYS
              This  will  set  the number of days in advance the user will begin receiving warnings that her password
              will expire, if the user's account supports password lifetimes.  Available to root only.

-i, --inactive DAYS



[root@oldboyedu ~]# su - oldboy -c pwd
/home/oldboy
[root@oldboyedu ~]# su - oldboy -c whoami
oldboy


怎么用su。

1、先登录普通用户，没事不允许登录root。
只有执行的任务需要root权限的时候才允许你登录root。
系统维护通道。
用su管理，必须知道root密码，安全隐患。
10个运维，都得知道root密码，安全隐患。

需求：
1、不用知道root密码还能管理服务器。
2、最小化管理服务器，想关机，就只给你halt权限。


sudo命令：
可以以最小化的权限（单个命令），执行命令时拥有root用户的权限

SUID 针对命令，任何用户执行命令都有root身份。    任何用户执行某个命令：模糊
SUDO 针对用户，给某个用户以root身份执行某个命令。指定用户执行某个命令：具体。


如何编辑配置sudo？

sudo是一个提权的命令（对应权限通过读取/etc/sudoers（严格语法）文件实现的）

配置/etc/sudoers可以使用visudo命令，或vim /etc/sudoers（不推荐）


[oldboy@oldboyedu ~]$ ls /root
ls: cannot open directory /root: Permission denied
完成上面的动作。

给oldboy用户，针对ls设置权限。

visudo进入编辑状态，100G

## Allow root to run any commands anywhere
root        ALL=(ALL)           ALL
oldboy      ALL=(ALL)           /usr/bin/ls,/bin/cp   #<===增加一行
用户        主机=（角色）       命令

注意：
1、路径要全路径：
which cp查
2、不要vim /etc/sudoers编辑，如果非要用编辑完visudo -c检查语法

oldboy是管理员，并且不要密码：
oldboy  ALL=(ALL)       NOPASSWD: ALL

登录后切到root运行。
[oldboy@oldboyedu ~]$ sudo su - root
Last login: Tue Mar 26 10:32:57 CST 2019 on pts/3
[root@oldboyedu ~]# 

为了安全禁止root远程连接linux。

工作中如何登录？使用普通用户登录然后利用sudo提权到root。
Wecomle to oldboy training 58期。
[oldboy@oldboyedu ~]$ whoami
oldboy
[oldboy@oldboyedu ~]$ sudo ls /root
a.txt  c.txt  data1  etc       oldboy        oldboy_b       oldboy_soft_link  pass  test.txt      user.log
b.txt  d      d.txt  grep.txt  oldboy_1.txt  oldboyedu.txt  oldboy.txt        test  test.txt.ori
[oldboy@oldboyedu ~]$ 
[oldboy@oldboyedu ~]$ 
[oldboy@oldboyedu ~]$ sudo su -
Last login: Tue Mar 26 11:42:09 CST 2019 on pts/0
[root@oldboyedu ~]# 


[root@oldboyedu ~]# su - oldboy
Last login: Tue Mar 26 10:44:08 CST 2019 on pts/3
[oldboy@oldboyedu ~]$ ls /root
ls: cannot open directory /root: Permission denied
[oldboy@oldboyedu ~]$ sudo -l

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.

[sudo] password for oldboy: 
Matching Defaults entries for oldboy on oldboyedu:
User oldboy may run the following commands on oldboyedu:
    (ALL) /bin/ls
[oldboy@oldboyedu ~]$ sudo ls /root
a.txt  c.txt  data1  etc       oldboy        oldboy_b       oldboy_soft_link  pass  test.txt      user.log
b.txt  d      d.txt  grep.txt  oldboy_1.txt  oldboyedu.txt  oldboy.txt        test  test.txt.ori
[oldboy@oldboyedu ~]$ ls /root
ls: cannot open directory /root: Permission denied
[oldboy@oldboyedu ~]$ 



练习：给普通用户oldgirl增加添加用户和删除用户权限。


root用户找回密码
https://baijiahao.baidu.com/s?id=1614000108255096283&wfr=spider&for=pc