MySQL用户和权限
在MySQL中有一个系统自身就带有的数据库叫MySQL,数据库装好以后系统自带了好几个数据库MySQL就是其中过一个,MySQL数据库有个用户账户权限相关的表叫user表,在其中就有创建的用户。
MySQL中完整的用户名是由用户+主机名形成,主机名决定了这个用户在哪个主机上能登陆。
一、用户的创建和密码修改
1.用户的创建
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create user 'USERNAME' @ 'HOST' identified by 'PASSWORD' ;
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USERNAME:用户名
HOST:主机地址
PASSWORD:密码
示例:
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MariaDB [(none)]> create user masuri@192.168.73.133 identified by 'centos' ;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> select user ,host, password from mysql. user ;
+ --------+-----------------------+-------------------------------------------+
| user | host | password |
+ --------+-----------------------+-------------------------------------------+
| root | localhost | |
| root | localhost.localdomain | |
| root | 127.0.0.1 | |
| root | ::1 | |
| | localhost | |
| | localhost.localdomain | |
| masuri | 192.168.73.133 | *128977E278358FF80A246B5046F51043A2B1FCED |
+ --------+-----------------------+-------------------------------------------+
7 rows in set (0.00 sec)
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MySQL中有匿名账户,可以通过跑安全加固脚本mysql_secure_installation来进行删除,也可以手动将其删除。
删除用户:
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DROP USER 'USERNAME' @ 'HOST' ;
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示例:
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MariaDB [(none)]> select user ,host, password from mysql. user ;
+ --------+-----------------------+-------------------------------------------+
| user | host | password |
+ --------+-----------------------+-------------------------------------------+
| root | localhost | |
| root | localhost.localdomain | |
| root | 127.0.0.1 | |
| root | ::1 | |
| | localhost | |
| | localhost.localdomain | |
| masuri | 192.168.73.133 | *128977E278358FF80A246B5046F51043A2B1FCED |
+ --------+-----------------------+-------------------------------------------+
7 rows in set (0.00 sec)
MariaDB [(none)]> DROP USER '' @ 'localhost' ;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> DROP USER '' @ 'localhost.localdomain' ;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> select user ,host, password from mysql. user ;
+ --------+-----------------------+-------------------------------------------+
| user | host | password |
+ --------+-----------------------+-------------------------------------------+
| root | localhost | |
| root | localhost.localdomain | |
| root | 127.0.0.1 | |
| root | ::1 | |
| masuri | 192.168.73.133 | *128977E278358FF80A246B5046F51043A2B1FCED |
+ --------+-----------------------+-------------------------------------------+
5 rows in set (0.00 sec)
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2.密码的修改
mysql密码的修改
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SET PASSWORD FOR user = PASSWORD ( 'cleartext password' )
UPDATE table SET password = password ( 'cleartext password' )
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示例:
对masuri用户做密码的修改
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MariaDB [(none)]> SET PASSWORD FOR masuri@192.168.73.133 = PASSWORD ( 'magedu' );
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> select user ,host, password from mysql. user ;
+ --------+-----------------------+-------------------------------------------+
| user | host | password |
+ --------+-----------------------+-------------------------------------------+
| root | localhost | |
| root | localhost.localdomain | |
| root | 127.0.0.1 | |
| root | ::1 | |
| masuri | 192.168.73.133 | *6B8CCC83799A26CD19D7AD9AEEADBCD30D8A8664 |
+ --------+-----------------------+-------------------------------------------+
#此时密码已经发生改变
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root账号口令为空,为root口令设置口令,由于一条一条的设置太过麻烦也可以使用修改表的操作来修改密码
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MariaDB [(none)]> update mysql. user set password = password ( 'centos' ) where user = 'root' ;
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
MariaDB [(none)]> select user ,host, password from mysql. user ;
+ --------+-----------------------+-------------------------------------------+
| user | host | password |
+ --------+-----------------------+-------------------------------------------+
| root | localhost | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | localhost.localdomain | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | 127.0.0.1 | *128977E278358FF80A246B5046F51043A2B1FCED |
| root | ::1 | *128977E278358FF80A246B5046F51043A2B1FCED |
| masuri | 192.168.73.133 | *6B8CCC83799A26CD19D7AD9AEEADBCD30D8A8664 |
+ --------+-----------------------+-------------------------------------------+
5 rows in set (0.00 sec)
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此时密码已经修改但依旧无法登陆,需要将权限刷新
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MariaDB [(none)]> FLUSH PRIVILEGES ;
Query OK, 0 rows affected (0.00 sec)
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二、MySQL权限管理
权限管理涉及到多种权限的类别,比如说有管理类、程序类、数据库级别、表级别和字段级别
管理类:能否创建用户,能否显示数据库列表,能否重新加载配置文件,能否关闭数据库,和复制相关的能否执行,能否管理进程,能否创建临时表,能否创建数据库中的文件。
程序类主要涉及3个程序,函数,存储过程和触发器,例如能否创建,修改,删除和执行这些程序库,表和字段级别的权限:比如能否在库,表字段里进行增、删、查、改等操作
1.授权GRANT
授权用户时如果用户不存在可以将其创建出来,在授权前首先要确认自己是管理员有授权的权限。
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GRANT
priv_type [(column_list)]
[, priv_type [(column_list)]] ...
ON [object_type] priv_level
TO user_specification [, user_specification] ...
[REQUIRE {NONE | ssl_option [[ AND ] ssl_option] ...}]
[ WITH with_option ...]
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示例:
创建一个wordpress的用户,并授权。
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MariaDB [(none)]> CREATE DATABASE wordpress;
Query OK, 1 row affected (0.02 sec)
MariaDB [(none)]> GRANT ALL ON wordpress.* TO wpuser@ '192.168.73.%' identified by 'mylinuxops' ;
Query OK, 0 rows affected (0.00 sec)
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2.查看用户的权限
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MariaDB [(none)]> show grants for wpuser@ '192.168.73.%' ;
+ ------------------------------------------------------------------------------------------------------------------+
| Grants for wpuser@192.168.73.% |
+ ------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser' @ '192.168.73.%' IDENTIFIED BY PASSWORD '*EC0DBFB480593BB6ED2EC028A4231A72D8137406' |
| GRANT ALL PRIVILEGES ON `wordpress`.* TO 'wpuser' @ '192.168.73.%' |
+ ------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
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3.授权的其他选项
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MAX_QUESRIES_PER_HOUR count #每小时最多查多少次
MAX_UPDATES_PER_HOUR count #每小时最多改多少次
MAX_CONNECTIONS_PER_HOUR count #每小时最多连多少次
MAX_USER_CONNECTIONS count #用户的最大数连接数
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取消权限
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REVOKE
priv_type [(column_list)]
[, priv_type [(column_list)]] ...
ON [object_type] priv_level
FROM user [, user ] ...
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示例:
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MariaDB [(none)]> revoke delete on wordpress.* from wpuser@ '192.168.73.%' ;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show grants for wpuser@ '192.168.73.%' ;
+ ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Grants for wpuser@192.168.73.% |
+ ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser' @ '192.168.73.%' IDENTIFIED BY PASSWORD '*EC0DBFB480593BB6ED2EC028A4231A72D8137406' |
| GRANT SELECT , INSERT , UPDATE , CREATE , DROP , REFERENCES , INDEX , ALTER , CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE , CREATE VIEW , SHOW VIEW , CREATE ROUTINE, ALTER ROUTINE, EVENT, TRIGGER ON `wordpress`.* TO 'wpuser' @ '192.168.73.%' |
+ ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
# 此时wpuser@ '192.168.73.%' 已经没有了 delete 权限
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MySQL的root口令破解
工作中有时候可能会遇到root口令丢失的情况,此时可以通过以下方法进行找回root口令
以下为示范如何破解root口令
一、密码未知无法登陆MySQL
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[root@localhost ~]# mysql
ERROR 1045 (28000): Access denied for user 'root' @ 'localhost' (using password : NO )
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二、破解
1.修改配置文件/etc/my.cnf,添加两行参数
skip_grant_tables:跳过授权表信息,此项生效后再次使用MySQL就无需使用密码了,但是远程的其他用户也可以不使用密码登陆,有一定的风险性
skip_networking:关闭网路功能,由于光启用skip_grant_tables选项,其他用户也可以无需密码登陆MySQL非常危险,所以需要关闭网路功能只允许本地的用户进行操作。
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[root@localhost ~]# vim /etc/my.cnf
[mysqld]
skip_networking= on #不启用网络功能
skip_grant_tables= on #跳过授权表
[root@localhost ~]# service mysqld restart #对位置文件修改后需要重新启动服务
Restarting mysqld (via systemctl): [ OK ]
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2.登陆MySQL,进行密码修改
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[root@localhost ~]# mysql #此时已经无需输入密码就能登陆
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 11
Server version: 10.2.23-MariaDB-log Source distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> UPDATE mysql. user SET password = PASSWORD ( '123456' ) where user = 'root' ; #对root的口令进行修改
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
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3.口令修改完毕后,需要将配置文件恢复
将刚才启用的两个选项进行注销或者删除,然后重启服务
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[root@localhost ~]# vim /etc/my.cnf
[mysqld]
#skip_networking= on #skip_grant_tables= on [root@localhost ~]# service mysqld restart
Restarting mysqld (via systemctl): [ OK ]
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4.使用新口令登陆MySQL
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[root@localhost ~]# mysql -uroot -p123456
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 10
Server version: 10.2.23-MariaDB-log Source distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>
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以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.51cto.com/11886307/2388443