目录
一.SElinux工作原理简介
通过mac方式管理进程，管理的目标是进程是否具有读取权限的文件（文件、目录、端口等），要使得进程和目标的安全上下文一致才能够顺利访问到资源（还要受文件资源的RWX等权限影响）。
#如下是我160主机的httpd的html目录的安全上下文内容，以ls -Z来查看，其中有4个字段，稍后作解释
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 27 13:29 ip11.system_u
身份标识，root表示root、system_u表示进程程序、unconfined_u表示一般用户相关身份
2.object_r
角色字段，可以判断是属于程序、文件、用户中的哪一种，object_r表示文件或目录资源，system_r表示是进程
3.httpd_sys_content_t
类型字段，作用域哪一个域
4.s0
灵敏度，一般会有s0、s1、s2，数值越大灵敏度越高
二.SElinux策略的具体使用详情
SElinux的开启和关闭在之前的文章已经介绍到，现在我们在关闭firewalld并且SElinux为Enforcing（Enforcing为强制限制，permissive为运行selinux但不强制，disabled为关闭selinux）的情况下进行演示，这里所有代码段均以httpd服务为例。
[root@R9 www]# systemctl status firewalld.service | grep Active
Active: inactive (dead)
[root@R9 www]# getenforce
Enforcing1.restorecon
（1）这个命令可以将安全上下文修改为原始默认的状态，如下所示
[root@R9 www]# ls -Zl #修改后安全上下文
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 27 13:29 ip1
[root@R9 www]# restorecon -R /www/ #进行重置
[root@R9 www]# ls -ZL
system_u:object_r:default_t:s0 ip
system_u:object_r:default_t:s0 ip1（2）可用参数
-R：将目录及其子目录一起修改
-v：将过程输出到屏幕上（详情）
2.semanage
（1）这个命令可以来进行查询和修改安全上下文设置，如下所示，我要修改我本机的html目录时就可以去查看httpd默认的安全上下文是怎样的，在后面就可以按照这个策略进行更改
[root@R9 www]# semanage fcontext -l | grep /var/www/html
/var/www/html(/.*)?/sites/default/files(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html(/.*)?/sites/default/settings\.php regular file system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html(/.*)?/uploads(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html(/.*)?/wp-content(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html(/.*)?/wp_backups(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html/[^/]*/cgi-bin(/.*)? all files system_u:object_r:httpd_sys_script_exec_t:s0
/var/www/html/cgi/munin.* all files system_u:object_r:munin_script_exec_t:s0
/var/www/html/configuration\.php all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html/munin(/.*)? all files system_u:object_r:munin_content_t:s0
/var/www/html/munin/cgi(/.*)? all files system_u:object_r:munin_script_exec_t:s0
/var/www/html/nextcloud/data(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0
/var/www/html/owncloud/data(/.*)? all files system_u:object_r:httpd_sys_rw_content_t:s0 （2）可用参数
-l：查询
-a：增加安全上下文设置
-m：修改设置
-d：删除设置
（3）这里以一个例子介绍一部分semanage对于端口的管理
如下所示，我配置了80和8090端口的http服务，80端口chcon了安全上下文，8090端口为chcon安全上下文并且没有配置其的端口放行，在重启服务时就会报错了
[root@R9 www]# semanage port -l | grep http_port
http_port_t tcp 80, 81, 443, 488, 8008, 8009, 8443, 9000
pegasus_http_port_t tcp 5988
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:default_t:s0 24 Dec 27 14:19 ip1
[root@R9 www]# cat /etc/httpd/conf.d/myweb.conf
<VirtualHost 192.168.2.160>
servername www.ssll.com
DocumentRoot /www/ip
<Directory "/www">
AllowOverride None
Require all granted
</Directory>
</VirtualHost>
<VirtualHost 192.168.2.160:8090>
DocumentRoot /www/ip1
<Directory "/www">
AllowOverride None
Require all granted
</Directory>
</VirtualHost>
[root@R9 www]# systemctl restart httpd
Job for httpd.service failed because the control process exited with error code.
See "systemctl status httpd.service" and "journalctl -xeu httpd.service" for details.
[root@R9 www]# systemctl status httpd
× httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Wed 2023-12-27 14:21:25 CST; 7s ago
Duration: 46min 40.807s
Docs: man:httpd.service(8)
Process: 4553 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
Main PID: 4553 (code=exited, status=1/FAILURE)
Status: "Reading configuration..."
CPU: 25ms
Dec 27 14:21:15 R9 systemd[1]: Starting The Apache HTTP Server...
Dec 27 14:21:25 R9 httpd[4553]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::20c:>
Dec 27 14:21:25 R9 httpd[4553]: (13)Permission denied: AH00072: make_sock: could not bind to address [::]:8090
Dec 27 14:21:25 R9 httpd[4553]: (13)Permission denied: AH00072: make_sock: could not bind to address 0.0.0.0:8090
Dec 27 14:21:25 R9 httpd[4553]: no listening sockets available, shutting down
Dec 27 14:21:25 R9 httpd[4553]: AH00015: Unable to open logs
Dec 27 14:21:25 R9 systemd[1]: httpd.service: Main process exited, code=exited, status=1/FAILURE
Dec 27 14:21:25 R9 systemd[1]: httpd.service: Failed with result 'exit-code'.
Dec 27 14:21:25 R9 systemd[1]: Failed to start The Apache HTTP Server.接下来添加8090服务端口，可以看到重启服务成功并且8090端口已被添加成功，也可以成功访问
[root@R9 www]# semanage port -a -t http_port_t -p tcp 8090
[root@R9 www]# systemctl restart httpd
🔐 Enter TLS private key passphrase for fe80::20c:29ff:fe49:e52%ens160:443 (RSA) : *******
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:default_t:s0 24 Dec 27 14:19 ip1
[root@R9 www]# semanage port -l | grep http_port_t
http_port_t tcp 8090, 80, 81, 443, 488, 8008, 8009, 8443, 9000
pegasus_http_port_t tcp 5988
[root@SLB ~]# curl 192.168.2.160:8090
hello删除端口时可以这样做
[root@R9 www]# semanage port -d -t http_port_t -p tcp 80903.chcon
（1）这个命令用于修改安全上下文，如下所示我按照上面我查询到的策略进行修改后，能够顺利访问到目录内容
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:default_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:default_t:s0 24 Dec 27 13:29 ip1
[root@R9 www]# chcon -t httpd_sys_rw_content_t /www/ -R
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_rw_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_rw_content_t:s0 24 Dec 27 13:29 ip1
[root@SLB ~]# curl 192.168.2.160
192.168.2.160 （2）可用参数
-R：将目录及其子目录一起修改
-t：跟安全上下文所要修改的字段内容
-u：跟身份标识
-r：跟角色字段
--reference=：这个表示按照哪个目录文件进行修改安全上下文
[root@R9 www]# restorecon -R /www #按照httpd默认的html目录进行修改
[root@R9 www]# chcon --reference=/var/www/html -R /www
[root@R9 www]# ls -Zl
total 0
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 23 21:38 ip
drwxr-xr-x. 2 root root system_u:object_r:httpd_sys_content_t:s0 24 Dec 27 13:29 ip1
[root@SLB ~]# curl 192.168.2.160
192.168.2.160 
