mysql 8.0.11 資料庫使用者密碼修改詭異的限制

近期，協助一客戶重置mysql 8.0.11的root密碼，碰到了奇怪的問題。

作業系統版本：rhel 7.6

資料庫版本：mysql 8.0.11

根據mysql 8.0官方文件說明，mysql的使用者密碼有限制，並且被硬編碼，沒有明確說明密碼長度是多少。

Warning

The MySQL user name length limit is hardcoded in MySQL servers and clients, and trying to circumvent it by modifying the definitions of the tables in the mysql database does not work.

You should never alter the structure of tables in the mysql database in any manner whatsoever except by means of the procedure that is described in Section 2.11, “Upgrading MySQL”. Attempting to redefine MySQL's system tables in any other fashion results in undefined and unsupported behavior. The server is free to ignore rows that become malformed as a result of such modifications.

另外，mysql 8.0不再支援password()函式，因此，不能像mysql5.x那樣通過update mysql.user表來修改使用者密碼。

但是，在mysql 8.0的root密碼重置時遇到報錯：

[mysql@mysql8~]$ mysql -uroot -p -S /home/mysql/mysql/tmp/mysql.sock

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 7

Server version: 8.0.11 MySQL Community Server - GPL

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

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

mysql>

mysql> 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

--update mysql.user重置使用者密碼失敗

mysql> update user set authentication_string = '123456' where user='root' and host='%' ;

Query OK, 1 row affected (0.00 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql> flush privileges;

Query OK, 0 rows affected (0.01 sec)

mysql> select user,host,authentication_string from mysql.user;

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

| user | host | authentication_string |

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

| root | % | 123456 |

| mysql.infoschema | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

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

5 rows in set (0.00 sec)

--password函式不被mysql8.0支援

mysql> update user set authentication_string =PASSWORD('123456') where user='root' and host='%' ;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('

123456') where user='root' and host='%'' at line 1

mysql>

--奇怪的是使用alter命令重置root密碼長度為6位時報錯，但是不是語法錯誤

mysql> alter user 'root'@'%' identified by '123456'; ERROR 1396 (HY000): Operation ALTER USER failed for 'root'@'%' --但是，將root密碼長度增加到8位時獲得成功

mysql> ALTER USER root IDENTIFIED WITH mysql_native_password BY '123456789';

Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

mysql> select user,host,authentication_string from mysql.user;

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

| user | host | authentication_string |

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

| root | % | *CC67043C7BCFF5EEA5566BD9B1F3C74FD9A5CF5D |

| mysql.infoschema | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

| mysql.session | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

| mysql.sys | localhost | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |

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

5 rows in set (0.00 sec)

但是，我本地的centos 7.6上的mysql 8.0重置root密碼缺沒有密碼長度限制，兩套庫用的是相同的引數檔案。

官方關於使用者密碼長度沒有特別說明，網上也沒有類似密碼長度問題的資料，很奇怪！

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/29357786/viewspace-2704307/，如需轉載，請註明出處，否則將追究法律責任。

mysql 8.0.11 資料庫使用者密碼修改詭異的限制

相關文章