mysql初始化、增删改查用户、授权

1. 数据库安全初始化

[root@elasticsearch my.cnf.d]# mysql_secure_installation        #安全初始化命令

NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):               #输入mysql的root账户默认密码（默认为空）
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n] y                      #是否设置root密码
New password:                                   #为root用户输入一个新密码
Re-enter new password:                          #再次输入密码
Password updated successfully!                  #密码更新成功
Reloading privilege tables..
 ... Success!

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] y                 #是否删除匿名用户
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] y           #是否允许root用户远程登录
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n]    #是否删除test数据库
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n]              #是否刷新以上操作，使其立即生效
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

• 以上操作完成后，命令行直接输入mysql无法登录数据库，使用本机外网地址也无法登录。

[root@elasticsearch my.cnf.d]# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@elasticsearch my.cnf.d]# mysql -uroot -h292.168.0.194 -p
Enter password: 
ERROR 1130 (HY000): Host 'node1' is not allowed to connect to this MariaDB server
[root@elasticsearch my.cnf.d]# mysql -uroot -h227.0.0.1 -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 14
Server version: 5.5.60-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

[root@elasticsearch my.cnf.d]# mysql -uroot -hlocalhost -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 15
Server version: 5.5.60-MariaDB MariaDB Server

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)]> show databases;

• 查看当前授权的用户和地址可见root仅授权了localhost和127.0.0.1可登录

MariaDB [(none)]> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
MariaDB [mysql]> select User,Host from user;
+------+-----------+
| User | Host      |
+------+-----------+
| root | 127.0.0.1 |
| root | ::1       |
| root | localhost |
+------+-----------+
3 rows in set (0.00 sec)

MariaDB [mysql]> 

2. 忘记管理员密码的解决办法：

1. 启动mysql前，编辑/etc/my.cnf，添加skip-grant-tables和skip-networking；

[mysqld]
skip-grant-tables
skip-networking
datadir=/var/lib/mysql

2. 通过UPDATE命令修改管理员密码；

[root@elasticsearch ~]# systemctl start mariadb
[root@elasticsearch ~]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 2
Server version: 5.5.60-MariaDB MariaDB Server

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 authentication_string=password('centos') where user='root' and Host = 'localhost';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> exit
Bye

3. 删除/etc/my.cnf中添加的内容，以正常方式启动mysqld进程；

[root@elasticsearch ~]# mysql -uroot -hlocalhost -pcentos
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3
Server version: 5.5.60-MariaDB MariaDB Server

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)]> 

3. 增、删、改、查用户

1. 查看用户：

• mysql中用户表在mysql.user中
• 查看用户示例：

MariaDB [(none)]> SELECT User,Host FROM mysql.user;
+-------+-------------+
| User  | Host        |
+-------+-------------+
| root  | 127.0.0.1   |
| root  | ::1         |
| root  | localhost   |
+-------+-------------+
6 rows in set (0.01 sec)

2. 添加用户
   • 格式：可一次创建多个用户

CREATE USER  'user'@'host' [IDENTIFIED BY [PASSWORD] 'password'] [,'user'@'host' [IDENTIFIED BY [PASSWORD] 'password']...]

• 例：

# 单条命令创建一个用户：
MariaDB [(none)]> CREATE USER 'lxk'@'localhost' IDENTIFIED BY PASSWORD 'linux.centos.com';
Query OK, 0 rows affected (0.00 sec)
# 以逗号为分隔，单条命令创建两个用户：
MariaDB [(none)]> CREATE USER 'test0'@'192.168.1.%' IDENTIFIED BY 'maria.centos.com','test1'@'192.168.1.%' IDENTIFIED BY 'maria.centos.com';
Query OK, 0 rows affected (0.00 sec)

3. 重命名用户：
   • 格式：
   • RENAME USER old_user TO new_user[, old_user TO new_user] ...

• 例：（创建用户时加了授权地址，修改时也需加上授权地址）

#查看当前用户：
MariaDB [(none)]> SELECT User,Host FROM mysql.user;
+-------+-------------+
| User  | Host        |
+-------+-------------+
| root  | 127.0.0.1   |
| test0 | 192.168.1.% |
| test1 | 192.168.1.% |
| root  | ::1         |
| lxk   | localhost   |
| root  | localhost   |
+-------+-------------+
6 rows in set (0.01 sec)

MariaDB [(none)]> RENAME USER 'test1'@'192.168.1.%' TO 'test001'@'192.168.1.%';
Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SELECT User,Host FROM mysql.user;
+---------+-------------+
| User    | Host        |
+---------+-------------+
| root    | 127.0.0.1   |
| test0   | 192.168.1.% |
| test001 | 192.168.1.% |

4. 删除用户：
   • 格式：
   • DROP USER 'user'@'host' [, 'user'@'host'] ...
   • 例：

MariaDB [(none)]> DROP USER 'test001'@'192.168.1.%';
Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SELECT User,Host FROM mysql.user;
+-------+------------+
| User  | Host       |
+-------+------------+
| root  | 127.0.0.1  |
| test0 | 192.168.1.%|
| root  | ::1        |
| lxk   | localhost  |
| root  | localhost  |
+-------+------------+
5 rows in set (0.00 sec)

5. 重新加载授权表：
   • 作用：有时操作并不会马上写到磁盘上，执行此命令可把操作马上同步到磁盘上。
   • 例：

MariaDB [(none)]> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

4. 用户授权相关：

1. 查看用户授权：

• 格式：
  • SHOW GRANTS [FOR 'user'@'host']

MariaDB [(none)]> show grants;          #不加用户，默认查找的是root用户的授权信息。
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost                                                                                                              |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*128977E278358FF80A246B5046F51043A2B1FCED' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                                           |
+----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

MariaDB [(none)]> show grants for 'test0'@'192.168.1.%';        #查看指定用户的授权信息。
+---------------------------------------------------------------------------------------------------------------+
| Grants for test0@192.168.1.%                                                                                  |
+---------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test0'@'192.168.1.%' IDENTIFIED BY PASSWORD '*5FC1DC57211AE5F87FC504DEEE4B7C65DEB2CBFA'|
+---------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

2. 给用户授权：

• 格式：

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 ...]

• 简化格式：

GRANT  priv_type ON  [object_type] priv_level TO user_specification [, user_specification]

    object_type:
        TABLE
        | FUNCTION
        | PROCEDURE

    priv_level:
        *
        | *.*                       #所有库的所有表
        | db_name.*                 #某个库的所有表
        | db_name.tbl_name          #某个库的某个表
        | tbl_name                  #某个表
        | db_name.routine_name      #某个库的某个routine

• 示例：

MariaDB [(none)]> GRANT all ON *.* TO 'test0'@'192.168.1%';
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GRANTS FOR 'test0'@'192.168.1%';
+------------------------------------------------------------------------------------------------------------------------+
| Grants for test0@192.168.1.%                                                                                           |
+------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'test0'@'192.168.1.%' IDENTIFIED BY PASSWORD '*5FC1DC57211AE5F87FC504DEEE4B7C65DEB2CBFA'|
+------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)
# 

3. 取消授权：REVOKE

• 格式

REVOKE  priv_type [(column_list)][, priv_type [(column_list)]] ...
    ON [object_type] priv_level
    FROM  'user'@'host' [,  'user'@'host'] ...

REVOKE ALL PRIVILEGES, GRANT OPTION
    FROM user [, user] ...

• 示例：

MariaDB [(none)]> REVOKE ALL PRIVILEGES FROM 'test0'@'192.168.1.%';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'FROM 'test0'@'192.168.1%'' at line 1
MariaDB [(none)]> REVOKE ALL PRIVILEGES ON *.* FROM 'test0'@'192.168.1.%';
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GRANTS FOR 'test0'@'192.168.1%';
+---------------------------------------------------------------------------------------------------------------+
| Grants for test0@192.168.1.%                                                                                  |
+---------------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'test0'@'192.168.1.%' IDENTIFIED BY PASSWORD '*5FC1DC57211AE5F87FC504DEEE4B7C65DEB2CBFA'|
+---------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)