mysql用户创建触发器权限不足跟参数log_bin_trust_function

问题描述

有业务反馈当前用户无法创建触发器和存储过程，让用户自己测试，该用户进行对表的增删改查等其他权限没有问题，这边用root用户查证，该用户拥有对当前库的所有权限，但是为什么就是创建不了触发器呢？创建语句不涉及其他库，只是对当前库进行创建触发器，下面自己进行测试。

处理过程：将参数log_bin_trust_function_creators设置为ON即可

现有一下疑问？

1.用户拥有对当前库的所有权限，但是为什么创建不了触发器呢？

2.log_bin_trust_function_creators参数打开或关闭对创建触发器有什么影响呢？

3.如果对用户授予一个对所有库的创建触发器，存储过程权限，会不会有效呢？

报错：

ERROR 1442 (HY000): Can't update table 't1' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.

测试过程：

1.创建测试相关用例

创建测试用例：

mysql> create database gwhdgl;

mysql> create user gwhdgl@'%' identified by '123';

mysql> grant all privileges on gwhdgl.* to gwhdgl@'%';

mysql> grant select on mysql.* to gwhdgl@'%';

mysql> show grants for gwhdgl@'%';

+----------------------------------------------------+

| Grants for gwhdgl@%                                |

+----------------------------------------------------+

| GRANT USAGE ON *.* TO 'gwhdgl'@'%'                 |

| GRANT ALL PRIVILEGES ON `gwhdgl`.* TO 'gwhdgl'@'%' |

| GRANT SELECT ON `mysql`.* TO 'gwhdgl'@'%'          |

+----------------------------------------------------+

3 rows in set (0.00 sec)

创建测试表：

mysql> select * from t1;

+------+--------+-----------+

| id   | name   | start_url |

+------+--------+-----------+

|    1 | 张三   | Y         |

|    2 | 李四   | Y         |

|    3 | 王五   | Y         |

|    4 | 马六   | Y         |

|    5 | 是无   | Y         |

|    6 | 亏刘   | Y         |

+------+--------+-----------+

6 rows in set (0.01 sec)

mysql>

mysql> select * from t2;

+------+--------+-----------+

| id   | name   | start_url |

+------+--------+-----------+

|    1 | 张三   | Y         |

|    2 | 李四   | Y         |

|    3 | 王五   | Y         |

|    4 | 马六   | Y         |

|    5 | 是无   | Y         |

|    6 | 亏刘   | NULL      |

+------+--------+-----------+

6 rows in set (0.00 sec)

2.创建触发器，报错ERROR 1442

mysql -ugwhdgl -p123 -h192.168.163.21 -P13306

DELIMITER ||
create trigger gwhdgl_t2_triggers before insert
on t2 for each row
begin
update gwhdgl.t1 set start_url='Y';
END
||

ERROR 1442 (HY000): Can't update table 't1' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.

从mysql.db查看到的权限

mysql> select * from mysql.db where user='gwhdgl' and host='%'\G;
*************************** 1. row ***************************
Host: %
Db: gwhdgl
User: gwhdgl
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Execute_priv: Y
Event_priv: Y
Trigger_priv: Y
*************************** 2. row ***************************
Host: %
Db: mysql
User: gwhdgl
Select_priv: Y
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Execute_priv: N
Event_priv: N
Trigger_priv: N
2 rows in set (0.00 sec)

ERROR:
No query specified

从mysql.user看到的权限

mysql> select * from mysql.user where user='gwhdgl' and host='%'\G;
*************************** 1. row ***************************
Host: %
User: gwhdgl
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions: 0
max_updates: 0
max_connections: 0
max_user_connections: 0
plugin: mysql_native_password
authentication_string: *23AE809DDACAF96AF0FD78ED04B6A265E05AA257
password_expired: N
password_last_changed: 2021-05-10 10:17:28
password_lifetime: NULL
account_locked: N
1 row in set (0.00 sec)

对当前库的权限具备完全，但是对其他库的权限没有，如果将对其他库的创建触发器权限给到gwhdgl用户，就是将mysql.user表的权限更改过来，会不会正常呢？

3.授予用户mysql.user表的权限

User表：存放用户账户信息以及全局级别（所有数据库）权限，决定了来自哪些主机的哪些用户可以访问数据库实例，如果有全局权限则意味着对所有数据库都有此权限
Db表：存放数据库级别的权限，决定了来自哪些主机的哪些用户可以访问此数据库
Tables_priv表：存放表级别的权限，决定了来自哪些主机的哪些用户可以访问数据库的这个表
Columns_priv表：存放列级别的权限，决定了来自哪些主机的哪些用户可以访问数据库表的这个字段
Procs_priv表：存放存储过程和函数级别的权限

root用户授权
mysql> grant create routine,execute,alter routine,trigger on *.* to gwhdgl@'%';

Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

mysql>

mysql> show grants for gwhdgl@'%';

+------------------------------------------------------------------------------+

| Grants for gwhdgl@%                                                          |

+------------------------------------------------------------------------------+

| GRANT EXECUTE, CREATE ROUTINE, ALTER ROUTINE, TRIGGER ON *.* TO 'gwhdgl'@'%' |

| GRANT ALL PRIVILEGES ON `gwhdgl`.* TO 'gwhdgl'@'%'                           |

| GRANT SELECT ON `mysql`.* TO 'gwhdgl'@'%'                                    |

+------------------------------------------------------------------------------+

3 rows in set (0.00 sec)

ERROR:
No query specified

mysql> select * from mysql.user where user='gwhdgl' and host='%'\G;
*************************** 1. row ***************************
Host: %
User: gwhdgl
Select_priv: N
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: Y
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: N
Event_priv: N
Trigger_priv: Y
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions: 0
max_updates: 0
max_connections: 0
max_user_connections: 0
plugin: mysql_native_password
authentication_string: *23AE809DDACAF96AF0FD78ED04B6A265E05AA257
password_expired: N
password_last_changed: 2021-05-10 10:17:28
password_lifetime: NULL
account_locked: N
1 row in set (0.00 sec)

ERROR:



gwhdgl用户看到对trigger的权限

mysql> DELIMITER ||
mysql> create trigger gwhdgl_t2_triggers before insert
-> on t2 for each row
-> begin
-> update gwhdgl.t1 set start_url='Y';
-> END
-> ||

ERROR 1419 (HY000): You do not have the SUPER privilege and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable)

经过测试，将mysql.db和mysql.user的权限都改回来，仍然没有用

4.在所有权限都保持的情况下，打开参数log_bin_trust_function_creators

mysql> set global log_bin_trust_function_creators=1;

gwhdgl用户

mysql> set global log_bin_trust_function_creators=1;
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ||
mysql> create trigger gwhdgl_t2_triggers before insert
-> on t2 for each row
-> begin
-> update gwhdgl.t1 set start_url='Y';
-> END
-> ||
Query OK, 0 rows affected (0.00 sec)

mysql> use gwhdgl;
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
mysql>
mysql>
mysql> drop trigger if exists gwhdgl_t1_triggers;
Query OK, 0 rows affected, 1 warning (0.00 sec)

经测试，打开log_bin_trust_function_creators参数可以让用户拥有创建触发器选项，此时用户的权限还是

| GRANT EXECUTE, CREATE ROUTINE, ALTER ROUTINE, TRIGGER ON *.* TO 'gwhdgl'@'%' |
| GRANT ALL PRIVILEGES ON `gwhdgl`.* TO 'gwhdgl'@'%' |
| GRANT SELECT ON `mysql`.* TO 'gwhdgl'@'%'

log_bin_trust_function_creators这个参数到底是什么意思？

当二进制日志启用后，这个变量就会启用。它控制是否可以信任存储函数创建者，不会创建写入二进制日志引起不安全事件的存储函数。如果设置为0（默认值），用户不得创建或修改存储函数，除非它们具有除CREATE ROUTINE或ALTER ROUTINE特权之外的SUPER权限。设置为0还强制使用DETERMINISTIC特性或READS SQL DATA或NO SQL特性声明函数的限制。如果变量设置为1，MySQL不会对创建存储函数实施这些限制。

所以这个参数是跟随log-bin的，控制打开log-bin模式后，开启主从复制模式，对写入二进制日志引起不安全事件的存储函数信任关系的一个限制，所以下面测试将log-bin关闭，mysql用户创建触发器需要什么权限呢？

5.关闭log-bin，目前用户拥有的权限是对当前库，和其他库的创建触发器的权限，测试成功

mysql> DELIMITER ||

mysql> create trigger gwhdgl_t2_triggers before insert

    -> on t2 for each row

    -> begin

    -> update gwhdgl.t1 set start_url='Y';

    -> END

    -> ||

Query OK, 0 rows affected (0.00 sec)

6.授予用户对其他库的触发器权限，目前是对当前库拥有创建触发器的权限，创建成功

将对其他库的权限收回来

mysql> revoke create routine,execute,alter routine,trigger on *.* from gwhdgl@'%';

Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

mysql> show grants for gwhdgl@'%';

+----------------------------------------------------+

| Grants for gwhdgl@%                                |

+----------------------------------------------------+

| GRANT USAGE ON *.* TO 'gwhdgl'@'%'                 |

| GRANT ALL PRIVILEGES ON `gwhdgl`.* TO 'gwhdgl'@'%' |

| GRANT SELECT ON `mysql`.* TO 'gwhdgl'@'%'          |

+----------------------------------------------------+

3 rows in set (0.00 sec)

测试下有没有对trigger的权限？

mysql> select user();

+-------------+

| user()      |

+-------------+

| gwhdgl@mha4 |

+-------------+

1 row in set (0.00 sec)

mysql> show grants for gwhdgl@'%';

+----------------------------------------------------+

| Grants for gwhdgl@%                                |

+----------------------------------------------------+

| GRANT USAGE ON *.* TO 'gwhdgl'@'%'                 |

| GRANT ALL PRIVILEGES ON `gwhdgl`.* TO 'gwhdgl'@'%' |

| GRANT SELECT ON `mysql`.* TO 'gwhdgl'@'%'          |

+----------------------------------------------------+

3 rows in set (0.00 sec)

mysql> DELIMITER ||

mysql> create trigger gwhdgl_t2_triggers before insert

    -> on t2 for each row

    -> begin

    -> update gwhdgl.t1 set start_url='Y';

    -> END

    -> ||

Query OK, 0 rows affected (0.00 sec)

结论：

1.创建触发器其实只需要用户对当前库的create routine,execute,alter routine,trigger相关权限就可以了

2.如果关闭log_bin_trust_function_creators模式，即便拥有了对当前库和其他库的创建触发器权限，仍然不能够创建，除非拥有SUPER privilege