一、用户的密码策略设置@H_336_126@

1.用户的密码文件

[root@tianyi ~]# cat /etc/passwd

root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/noLOGin
adm:x:3:4:adm:/VAR/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:oPErator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:65534:65534:Kernel Overflow User:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
systemd-coredump:x:999:997:systemd Core Dumper:/:/sbin/nologin
systemd-resolve:x:193:193:systemd Resolver:/:/sbin/nologin
tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
polkITd:x:998:996:User for polkitd:/:/sbin/nologin
unbound:x:997:994:Unbound DNS resolver:/etc/unbound:/sbin/nologin
libstoragemgmt:x:996:993:daemon account for libstoragemgmt:/var/run/lsm:/sbin/nologin
setroubleshoot:x:995:992::/var/lib/setroubleshoot:/sbin/nologin
clevis:x:994:990:Clevis Decryption Framework unPRivileged user:/var/cache/clevis:/sbin/nologin
cockpit-ws:x:993:989:User for cockpit-ws:/:/sbin/nologin
sSSD:x:992:988:User for sssd:/:/sbin/nologin
insights:x:991:987:Red hat Insights:/var/lib/insights:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
pesign:x:990:986:Group for the pesign signing daemon:/var/run/pesign:/sbin/nologin
chrony:x:989:985::/var/lib/chrony:/sbin/nologin
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin
admin:x:1000:1000::/home/admin:/bin/bash
nginx:x:988:984:Nginx web server:/var/lib/nginx:/sbin/nologin
MySQL:x:27:27:MySQL Server:/var/lib/mysql:/sbin/nologin
zabbix:x:987:983:Zabbix Monitoring System:/var/lib/zabbix:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
~          

2.用户的密码期限配置

①查看用户密码期限

[root@tianyi ~]# 
[root@tianyi ~]# chage -l user1
Last password change					: Nov 25, 2025      #最后一次密码变更时间
Password expires					: never             # 密码到期
Password inactive					: never             #   密码禁止
Account expires						: never             # 账户到期
Minimum number of days between password change		: 0             #更改密码的最短天数
Maximum number of days between password change		: 99999         # 更改密码的最长天数
Number of days of warning before password expires	: 7     # 密码到期之前警告天数
[root@tianyi ~]# 

②修改密码期限

[root@tianyi ~]# chage -m 0 -M 90 -W7 -i 14 user1
[root@tianyi ~]# chage -l user1
Last password change					: Nov 25, 2025
Password expires					: Feb 23, 2026
Password inactive					: Mar 09, 2026
Account expires						: never
Minimum number of days between password change		: 0
Maximum number of days between password change		: 90
Number of days of warning before password expires	: 7

③强制用户下一次修改密码

[root@tianyi ~]# chage -d 0 user1

④用户到期时间设置

[root@tianyi ~]# chage -E 2021-10-01 user1
[root@tianyi ~]# chage -l user1
Last password change					: password must be changed
Password expires					: password must be changed
Password inactive					: password must be changed
Account expires						: Oct 01, 2021
Minimum number of days between password change		: 0
Maximum number of days between password change		: 90
Number of days of warning before password expires	: 7

3.查看当前用户存在

[root@tianyi ~]# id user1
uid=1001(user1) gid=1001(user1) groups=1001(user1)
[root@tianyi ~]# 

二、监控系统用户登录

1.查看当前登录用户

[root@tianyi ~]# w
 11:54:10 up 89 days, 20:42,  1 user,  load average: 0.04, 0.05, 0.00
USER     TTY      From             LOGIN@   idle   JCPU   PCPU WHAT
root     pts/0    183.92.102.127   11:14    0.00s  0.06s  0.00s w

2.用户登录和重启记录

[root@node1 ~]# last |head
root     pts/0        192.168.200.1    Fri Sep 17 22:32   still logged in
reboot   system boot  4.18.0-80.el8.x8 Fri Sep 17 22:29   still running
root     pts/0        192.168.200.1    Mon Sep 13 20:28 - crash (4+02:00)
reboot   system boot  4.18.0-80.el8.x8 Mon Sep 13 20:22   still running
root     pts/2        192.168.200.1    Wed Sep  1 20:19 - 01:04  (04:45)
root     pts/1        192.168.200.1    Mon Aug 30 23:11 - 22:59 (1+23:47)
root     pts/0        192.168.200.1    Mon Aug 30 20:04 - 22:59 (2+02:54)
reboot   system boot  4.18.0-80.el8.x8 Mon Aug 30 20:03   still running
root     pts/0        192.168.200.1    Mon Aug 30 19:59 - 20:00  (00:00)
root     pts/1        192.168.200.1    Mon Aug 30 16:36 - 19:59  (03:23)
[root@node1 ~]# 

3.用户登录失败记录

[root@node1 ~]# lastb

btmp begins Mon Sep 13 20:23:03 2021
[root@node1 ~]#

4.登录日志

[root@node1 ~]# lastlog 
Username         Port     From             Latest
root             pts/0    192.168.200.1    Fri Sep 17 22:32:06 +0800 2021
bin                                        **Never logged in**
daemon                                     **Never logged in**
adm                                        **Never logged in**
lp                                         **Never logged in**
sync                                       **Never logged in**
shutdown                                   **Never logged in**
halt                                       **Never logged in**
mail                                       **Never logged in**
operator                                   **Never logged in**
games                                      **Never logged in**
ftp                                        **Never logged in**
nobody                                     **Never logged in**
dbus                                       **Never logged in**
systemd-coredump                           **Never logged in**
systemd-resolve                            **Never logged in**
tss                                        **Never logged in**
polkitd                                    **Never logged in**
geoclue                                    **Never logged in**
rtkit                                      **Never logged in**
pulse                                      **Never logged in**

三、用户的提权

[root@node1 ~]# vim /etc/sudoers.d/user1
user1 ALL= (ALL) NOPASSWD: /usr/bin/passwd, /usr/bin/mkdir
[user1@node1 ~]$ sudo mkdir file01
[user1@node1 ~]$ ls -l file01
total 0
[user1@node1 ~]$ ls -ld file01
drwxr-xr-x 2 root root 6 Sep 17 22:49 file01
[user1@node1 ~]$ mkdir file02
[user1@node1 ~]$ ls -ld file02
drwxrwxr-x 2 user1 user1 6 Sep 17 22:49 file02
[user1@node1 ~]$ 

四、ACL权限配置

1.查看文件的ACL权限

访问控制列表，可以实现更细致的访问控制

[root@node1 ~]# getfacl file
# file: file
# owner: root
# group: root
user::rw-
group::r--
other::r--

2.给指定用户设置ACL权限

[root@node1 ~]# setfacl -m u:user1:rx- file
[root@node1 ~]# getfacl file
# file: file
# owner: root
# group: root
user::rw-
user:user1:r-x
group::r--
mask::r-x
other::r--

3.给文件拥有人设置ACL权限

[root@node1 ~]# setfacl -m u::rwx file
[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
user:user1:r-x
group::r--
mask::r-x
other::r--

4.给指定用户组设置权限

①新建用户组及添加组内用户

[root@node1 ~]# groupadd HR
[root@node1 ~]# groupmems -g HR -a user1
[root@node1 ~]# groupmems -g HR -l
user1 

②设置文件的用户组权限

[root@node1 ~]# setfacl -m g:HR:rwx file
[root@node1 ~]# getfacl file
# file: file
# owner: root
# group: root
user::rwx
user:user1:r-x
group::r--
group:HR:rwx
mask::rwx
other::r--

[root@node1 ~]# 

5.给文件拥有组设置权限

[root@node1 ~]# setfacl -m g::rx- file
[root@node1 ~]# getfacl file
# file: file
# owner: root
# group: root
user::rwx
user:user1:r-x
group::r-x
group:HR:rwx
mask::rwx
other::r--

[root@node1 ~]# 

6.给文件其他人设置权限

[root@node1 ~]# setfacl -m o::rw- file
[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
user:user1:r-x
group::r-x
group:HR:rwx
mask::rwx
other::rw-

7.删除文件高级权限

①删除指定用户权限

[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
user:user1:r-x
group::r-x
group:HR:rwx
mask::rwx
other::rw-

[root@node1 ~]# setfacl -x u:user1 file
[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
group::r-x
group:HR:rwx
mask::rwx
other::rw-

[root@node1 ~]# 

②删除指定组的ACL权限

[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
group::r-x
group:HR:rwx
mask::rwx
other::rw-

[root@node1 ~]# setfacl -x g:HR file
[root@node1 ~]# getfacl  file
# file: file
# owner: root
# group: root
user::rwx
group::r-x
mask::r-x
other::rw-

[root@node1 ~]# 

③递归修改ACL权限

[root@node1 ~]# getfacl ./dir01/
# file: dir01/
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

[root@node1 ~]# getfacl ./dir01/test.txt 
# file: dir01/test.txt
# owner: root
# group: root
user::rw-
group::r--
other::r--

[root@node1 ~]# setfacl -R -m u:user1:rw- ./dir01/
[root@node1 ~]# getfacl ./dir01/
# file: dir01/
# owner: root
# group: root
user::rwx
user:user1:rw-
group::r-x
mask::rwx
other::r-x

[root@node1 ~]# getfacl ./dir01/test.txt 
# file: dir01/test.txt
# owner: root
# group: root
user::rw-
user:user1:rw-
group::r--
mask::rw-
other::r--

[root@node1 ~]# 

④清除所有ACL权限

setfacl -b

五、文件与目录的特殊权限

1.进程与文件的属主与属组

前提F1a;进程有属主和属组；文件有属主和属组；
(1) 任何一个可执行程序文件能不能启动为进程：取决于发起者对程序文件是否拥有执行权限；
(2) 启动为进程之后，其进程的属主为发起者；进程的属组为发起者所属的组；
(3) 进程访问文件时的权限，取决于进程的发起者：
(4) 进程的发起者，同文件的属主：则应用文件属主权限；
(5) 进程的发起者，属于文件的属组；则应用文件属组权限；
(6) 应用文件“其它”权限；

2.suid高级权限

ps:/usr/bin/passwd root

1.当一个文件有suid的权限时，那么其他用户来执行该文件时，临时获得文件拥有人的权限
2.suid的权限只能用在二进制的文件上，一般是针对命令
3.只能设置在文件上，设置目录上无意义
chmod u+s file

[root@node1 ~]# getfacl /usr/bin/passwd 
getfacl: Removing leading '/' from absolute path names
# file: usr/bin/passwd
# owner: root
# group: root
# flags: s--
user::rwx
group::r-x
other::r-x

3.sgid高级权限

1.当一个文件有sgid的权限时，那么其他用户来执行该文件时，临时获得文件拥有组的权限。
2.当一个目录有sgid的权限时，那么任何人在该目录下创建文件（包括目录）时，该文件的拥有组继承目录的组。

chmod  g+s directory

[root@node1 ~]# chmod g+s dir01/
[root@node1 ~]# getfacl dir01/
# file: dir01/
# owner: root
# group: root
# flags: -s-
user::rwx
user:user1:rw-
group::r-x
mask::rwx
other::r-x

[root@node1 ~]# touch dir01/list.txt
[root@node1 ~]# getfacl dir01/list.txt 
# file: dir01/list.txt
# owner: root
# group: root
user::rw-
group::r--
other::r--

4.sticky高级权限

1.用在目录上，当一个目录有stciky的权限时，那么其他用户只能删除拥有人是自己的文件。
chmod  o+t directory

六、默认权限与反掩码

1.root用户文件的默认权限

默认权限 umask 022
root 
文件  644 
目录  755

2.普通用户文件的默认权限

普通用户 002
文件  664
目录  775

3.umask配置文件

[root@node1 ~]# cat /etc/bashrc |grep umask
    # By default, we want umask to get set. This sets it for non-login shell.
       umask 002
       umask 022
[root@node1 ~]# 

4.修改umask

# .bashrc
  
# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv=';mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi
~         


# .bashrc
  
# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi
~         

5.umask和mask的权限计算

[root@node1 ~]# mkdir dir02/
[root@node1 ~]# ls -ld dir02/
drwxr-xr-x 2 root root 6 Sep 18 12:30 dir02/
[root@node1 ~]# touch file02
[root@node1 ~]# ll file02
-rw-r--r-- 1 root root 0 Sep 18 12:30 file02
[root@node1 ~]#