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ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

为了加强安全性,MySQL5.7为root用户随机生成了一个密码,在error log中,关于error log的位置,如果安装的是RPM包,则默认是/var/log/mysqld.log

一般可通过log_error设置。

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mysql> select @@log_error;
+---------------------+
| @@log_error |
+---------------------+
| /var/log/mysqld.log |
+---------------------+
1 row in set (0.00 sec)

可通过grep “password” /var/log/mysqld.log命令获取MySQL的临时密码

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2016-01-19T05:16:36.218234Z 1 [Note] A temporary password is generated for root@localhost: waQ,qR%be2(5

用该密码登录到服务端后,必须马上修改密码,不然会报如下错误:

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mysql> select user();
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

如果只是修改为一个简单的密码,会报以下错误:

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mysql>  ALTER USER USER() IDENTIFIED BY '12345678';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

这个其实与validate_password_policy的值有关。

validate_password_policy有以下取值:

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Policy	Tests Performed
0?or?LOW Length
1?or?MEDIUM Length; numeric, lowercase/uppercase, and special characters
2?or?STRONG Length; numeric, lowercase/uppercase, and special characters; dictionary file

默认是1,即MEDIUM,所以刚开始设置的密码必须符合长度,且必须含有数字,小写或大写字母,特殊字符。

有时候,只是为了自己测试,不想密码设置得那么复杂,譬如说,我只想设置root的密码为123456。

必须修改两个全局参数:

首先,修改validate_password_policy参数的值

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

这样,判断密码的标准就基于密码的长度了。这个由validate_password_length参数来决定。

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mysql> select @@validate_password_length;
+----------------------------+
| @@validate_password_length |
+----------------------------+
| 8 |
+----------------------------+
1 row in set (0.00 sec)

validate_password_length参数默认为8,它有最小值的限制,最小值为:

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validate_password_number_count
+ validate_password_special_char_count
+ (2 * validate_password_mixed_case_count)

其中,validate_password_number_count指定了密码中数据的长度,validate_password_special_char_count指定了密码中特殊字符的长度,validate_password_mixed_case_count指定了密码中大小字母的长度。

这些参数,默认值均为1,所以validate_password_length最小值为4,如果你显性指定validate_password_length的值小于4,尽管不会报错,但validate_password_length的值将设为4。如下所示:

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mysql> select @@validate_password_length;
+----------------------------+
| @@validate_password_length |
+----------------------------+
| 8 |
+----------------------------+
1 row in set (0.00 sec)

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

mysql> select @@validate_password_length;
+----------------------------+
| @@validate_password_length |
+----------------------------+
| 4 |
+----------------------------+
1 row in set (0.00 sec)

如果修改了validate_password_number_count,validate_password_special_char_count,validate_password_mixed_case_count中任何一个值,则validate_password_length将进行动态修改。

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mysql> select @@validate_password_length;
+----------------------------+
| @@validate_password_length |
+----------------------------+
| 4 |
+----------------------------+
1 row in set (0.00 sec)

mysql> select @@validate_password_mixed_case_count;
+--------------------------------------+
| @@validate_password_mixed_case_count |
+--------------------------------------+
| 1 |
+--------------------------------------+
1 row in set (0.00 sec)

mysql> set global validate_password_mixed_case_count=2;
Query OK, 0 rows affected (0.00 sec)

mysql> select @@validate_password_mixed_case_count;
+--------------------------------------+
| @@validate_password_mixed_case_count |
+--------------------------------------+
| 2 |
+--------------------------------------+
1 row in set (0.00 sec)

mysql> select @@validate_password_length;
+----------------------------+
| @@validate_password_length |
+----------------------------+
| 6 |
+----------------------------+
1 row in set (0.00 sec)

当然,前提是validate_password插件必须已经安装,MySQL5.7是默认安装的。

那么如何验证validate_password插件是否安装呢?可通过查看以下参数,如果没有安装,则输出将为空。

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mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password_dictionary_file | |
| validate_password_length | 6 |
| validate_password_mixed_case_count | 2 |
| validate_password_number_count | 1 |
| validate_password_policy | LOW |
| validate_password_special_char_count | 1 |
+--------------------------------------+-------+
6 rows in set (0.00 sec)

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