MySQL系列之六 用戶與授權

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一、用戶管理

1、用戶賬號

用戶的賬號由用戶名和HOST倆部分組成（’USERNAME’@’HOST’）

HOST的表示：

  • 主機名
  • 具體IP地址
  • 網段/掩碼

可以使用通配符表示，%和_；192.168.%即表示這個網段的所有主機

2、增加刪除賬號

主要：在數據庫中修改瞭用戶信息需要執行FLUSH PRIVILEGES;來刷新授權表使其生效

創建

  MariaDB [mysql]> CREATE USER 'user1'@'192.168.%';
  MariaDB [mysql]> CREATE USER 'user2'@'192.168.%' IDENTIFIED BY 'your_password';
  MariaDB [mysql]> SELECT user,host,password FROM user;
  +-------+-----------+-------------------------------------------+
  | user  | host      | password                                  |
  +-------+-----------+-------------------------------------------+
  | root  | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root  | centos7   |                                           |
  | root  | 127.0.0.1 |                                           |
  | root  | ::1       |                                           |
  |       | localhost |                                           |
  |       | centos7   |                                           |
  | user1 | 192.168.% |                                           |
  | user2 | 192.168.% | *9E72259BA9214F692A85B240647C4D95B0F2E08B |
  +-------+-----------+-------------------------------------------+

刪除

  MariaDB [mysql]> DROP USER user2@'192.168.%';
  MariaDB [mysql]> SELECT user,host,password FROM user;      
  +-------+-----------+-------------------------------------------+
  | user  | host      | password                                  |
  +-------+-----------+-------------------------------------------+
  | root  | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root  | centos7   |                                           |
  | root  | 127.0.0.1 |                                           |
  | root  | ::1       |                                           |
  |       | localhost |                                           |
  |       | centos7   |                                           |
  | user1 | 192.168.% |                                           |
  +-------+-----------+-------------------------------------------+

重命名

  MariaDB [mysql]> RENAME USER user1@'192.168.%' TO testuser@'%';
  MariaDB [mysql]> SELECT user,host,password FROM mysql.user;
  +----------+-----------+-------------------------------------------+
  | user     | host      | password                                  |
  +----------+-----------+-------------------------------------------+
  | root     | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root     | centos7   |                                           |
  | root     | 127.0.0.1 |                                           |
  | root     | ::1       |                                           |
  |          | localhost |                                           |
  |          | centos7   |                                           |
  | testuser | %         |                                           |
  +----------+-----------+-------------------------------------------+

修改密碼

  MariaDB [mysql]> SET PASSWORD FOR testuser@'%' =PASSWORD('testpass');
  MariaDB [mysql]> SELECT user,host,password FROM mysql.user;          
  +----------+-----------+-------------------------------------------+
  | user     | host      | password                                  |
  +----------+-----------+-------------------------------------------+
  | root     | localhost | *4A54C3F37C03C7FBACE31591D6A8C546F93DF5C5 |
  | root     | centos7   |                                           |
  | root     | 127.0.0.1 |                                           |
  | root     | ::1       |                                           |
  |          | localhost |                                           |
  |          | centos7   |                                           |
  | testuser | %         | *00E247AC5F9AF26AE0194B41E1E769DEE1429A29 |
  +----------+-----------+-------------------------------------------+

其他修改密碼的方法：

​ UPDATE user SET password=PASSWORD('testpass') WHERE user='testuser';


​ # mysqladmin -uroot -poldpass password 'newpass'

3、破解管理賬號密碼

空數據庫的情況下恢復密碼

  # systemctl stop mariadb
  # rm -rf /var/lib/mysql/*  #刪庫跑路
  # systemctl start mariadb

有數據的情況下恢復密碼

  1）在/etc/my.cnf配置文件的[mydqld]下添加skip-grant-tables和skip-networking參數

  2）# systemctl restart mariadb 重啟服務

  3）執行mysql登錄到數據庫

  4）MariaDB [(none)]> UPDATE mysql.user SET password=PASSWORD(‘newpassword’) WHERE user=’root’ AND host=’localhost’;  #更新密碼

  5）MariaDB [(none)]> FLUSH PRIVILEGES;  #刷新授權表

  6）退出，修改配置文件，刪除skip-grant-tables和skip-networking參數，重啟服務
也可以在啟動mysqld進程時，為其使用如下選項：

–skip-grant-tables

​ –skip-networking

二、授權管理

1、授權

​ 語法：GRANT priv_type ON [object_type] priv_level TO user@’%’ [IDENTIFIED BY ‘password’] [WITH GRANT OPTION];

授權時如果用戶不存在則創建，所以我們一般不會單獨去創建一個用戶，而是授權創建一塊完成。

priv_type 授權類型

– SELECT

– ​INSERT

– ​UPDATE

– ​DELETE

– ​CREATE

– ​DROP

– INDEX

– ALTER

– ​SHOW DATABASES

– ​CREATE TEMPORARY TABLES

– ​LOCK TABLES

– ​CREATE VIEW

– SHOW VIEW

– CREATE USER

– ALL PRIVILEGES 或 ALL

object_type 授權對象

– TABLE

– FUNCTION

– PROCEDURE

priv_level 授權級別

– *或*.* 表示所有庫

– db_name.* 表示指定庫中的所有表

– db_name.tbl_name 指定庫中的指定表

– tbl_name 表示當前庫的表

– db_name.routine_name 表示指定庫的函數,存儲過程,觸發器

WITH GRANT OPTION

– MAX_QUERIES_PER_HOUR count

– MAX_UPDATES_PER_HOUR count

– MAX_CONNECTIONS_PER_HOUR count

– MAX_USER_CONNECTIONS count

MariaDB [school]> GRANT SELECT(stuid,name) ON TABLE school.students TO admin@'%' IDENTIFIED BY 'admin';  #把students表的stuid和name字段的查詢權限授權於admin@'%'用戶
MariaDB [school]> FLUSH PRIVILEGES;  #刷新授權表

2、查詢授權

MariaDB [school]> SHOW GRANTS FOR admin@'%'\G  #查看指定用戶的權限
*************************** 1. row ***************************
Grants for admin@%: GRANT USAGE ON *.* TO 'admin'@'%' IDENTIFIED BY PASSWORD '*4ACFE3202A5FF5CF467898FC58AAB1D615029441'
*************************** 2. row ***************************
Grants for admin@%: GRANT SELECT (stuid, name) ON `school`.`students` TO 'admin'@'%'

[root@working ~]# mysql -uadmin -padmin -h192.168.0.7
MariaDB [(none)]> SHOW GRANTS FOR CURRENT_USER()\G  #查詢自己的權限
*************************** 1. row ***************************
Grants for admin@%: GRANT USAGE ON *.* TO 'admin'@'%' IDENTIFIED BY PASSWORD '*4ACFE3202A5FF5CF467898FC58AAB1D615029441'
*************************** 2. row ***************************
Grants for admin@%: GRANT SELECT (stuid, name) ON `school`.`students` TO 'admin'@'%'

3、收回授權

MariaDB [school]> REVOKE SELECT(stuid) ON school.students FROM admin@'%';  #收回admin@'%'用戶對stuid字段的查詢權限

總結

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