一、如何拒绝用户从某个精确ip访问数据库
假如在mysql.user表中存在用户‘mydba‘@‘192.168.85.%‘，现在想拒绝此用户从某个精确ip访问数据库
# 创建精确ip用户，分配不同的密码 mysql> create user ‘mydba‘@‘192.168.85.1‘ identified by ‘otherpwd‘; # 精确匹配，这个ip进来的密码为otherpwd，由于密码不匹配拒绝登录 mydba@192.168.85.132,3306 [(none)]> select user,host,authentication_string from mysql.user where user=‘mydba‘; +-------+--------------+-------------------------------------------+ | user | host | authentication_string | +-------+--------------+-------------------------------------------+ | mydba | 192.168.85.% | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | | mydba | 192.168.85.1 | *33D5FAF1A32909300D21AB5A38FA4F215D9FCB26 | +-------+--------------+-------------------------------------------+ 2 rows in set (0.00 sec) mydba@192.168.85.132,3306 [(none)]> select password(‘mysql5719‘),password(‘otherpwd‘); +-------------------------------------------+-------------------------------------------+ | password(‘mysql5719‘) | password(‘otherpwd‘) | +-------------------------------------------+-------------------------------------------+ | *A7E26519238B6EA2F943D5FAC3CD7812AD8F87E5 | *33D5FAF1A32909300D21AB5A38FA4F215D9FCB26 | +-------------------------------------------+-------------------------------------------+ 1 row in set, 2 warnings (0.00 sec)
此时用户‘mydba‘@‘192.168.85.1‘，即用户名mydba从192.168.85.1机器上访问，必须使用otherpwd才能登录
二、使用mysqladmin修改用户密码，当存在同名user(不同host)时，修改的是哪个用户的密码
mydba@192.168.85.132,3306 [(none)]> show master status; +------------------+----------+--------------+------------------+----------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+----------------------------------------------+ | mysql-bin.000116 | 3175 | | | 8ab82362-9c37-11e7-a858-000c29c1025c:1-69371 | +------------------+----------+--------------+------------------+----------------------------------------------+ 1 row in set (0.00 sec) mydba@192.168.85.132,3306 [(none)]> exit Bye [root@ZST1 ~]# mysqladmin -h192.168.85.132 -P3306 -umydba -p password newpwd Enter password: mysqladmin: [Warning] Using a password on the command line interface can be insecure. Warning: Since password will be sent to server in plain text, use ssl connection to ensure password safety. [root@ZST1 ~]#
此时修改的是哪个用户密码？‘mydba‘@‘192.168.85.1‘还是‘mydba‘@‘192.168.85.%‘？还是两者都修改了？
先说结论：看你从哪个客户端发起命令，仅修改与其匹配的current_user()对应的密码。mysqladmin中需要提供user+password以登录到MySQL中，在登录验证过程中MySQL已经对其进行精确匹配
2.1、current_user()为mydba@192.168.85.%，对应修改‘mydba‘@‘192.168.85.%‘的密码
# 前面的mysqladmin在ZST1(192.168.85.132)上执行，对应的current_user()为mydba@192.168.85.% mydba@192.168.85.132,3306 [(none)]> select user,host,authentication_string from mysql.user where user=‘mydba‘; +-------+--------------+-------------------------------------------+ | user | host | authentication_string | +-------+--------------+-------------------------------------------+ | mydba | 192.168.85.% | *1FA85AA204CC12B39B20E8F1E839D11B3F9E6AA4 | | mydba | 192.168.85.1 | *33D5FAF1A32909300D21AB5A38FA4F215D9FCB26 | +-------+--------------+-------------------------------------------+ 2 rows in set (0.01 sec)
2.2、current_user()为mydba@192.168.85.1，对应修改‘mydba‘@‘192.168.85.1‘的密码
# 从192.168.85.1上执行mysqladmin，要使用otherpwd密码才能执行 C:\Users\Administrator>mysqladmin -h192.168.85.132 -P3306 -umydba -p password newpwd1 Enter password: newpwd mysqladmin: connect to server at ‘192.168.85.132‘ failed error: ‘Access denied for user ‘mydba‘@‘192.168.85.1‘ (using password: YES)‘ C:\Users\Administrator>mysqladmin -h192.168.85.132 -P3306 -umydba -p password newpwd1 Enter password: otherpwd Warning: Using a password on the command line interface can be insecure. Warning: Server version is 5.7 or greater. The password will be sent to server in plain text. Upgrade the mysqladmin to a version that matches the server‘‘s version. C:\Users\Administrator>
我们查看修改后的密码，以及binlog
# 查看修改后的密码，分别对应是不从客户端修改 mydba@192.168.85.132,3306 [(none)]> select user,host,authentication_string from mysql.user where user=‘mydba‘; +-------+--------------+-------------------------------------------+ | user | host | authentication_string | +-------+--------------+-------------------------------------------+ | mydba | 192.168.85.% | *1FA85AA204CC12B39B20E8F1E839D11B3F9E6AA4 | | mydba | 192.168.85.1 | *12AB8416B918C0EC1528FD04A686AE12D97A4A5D | +-------+--------------+-------------------------------------------+ 2 rows in set (0.01 sec) mydba@192.168.85.132,3306 [(none)]> select password(‘newpwd‘),password(‘newpwd1‘); +-------------------------------------------+-------------------------------------------+ | password(‘newpwd‘) | password(‘newpwd1‘) | +-------------------------------------------+-------------------------------------------+ | *1FA85AA204CC12B39B20E8F1E839D11B3F9E6AA4 | *12AB8416B918C0EC1528FD04A686AE12D97A4A5D | +-------------------------------------------+-------------------------------------------+ 1 row in set, 2 warnings (0.00 sec) # 查看binlog [root@ZST1 logs]# mysqlbinlog -vv --base64-output=decode-rows mysql-bin.000116 --start-position=3175 /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/; /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/; DELIMITER /*!*/; # at 3175 #171129 17:37:27 server id 1323306 end_log_pos 3240 CRC32 0xf0c57f78 GTID last_committed=13 sequence_number=14 rbr_only=no SET @@SESSION.GTID_NEXT= ‘8ab82362-9c37-11e7-a858-000c29c1025c:69372‘/*!*/; # at 3240 #171129 17:37:27 server id 1323306 end_log_pos 3443 CRC32 0x8a596597 Query thread_id=33 exec_time=0 error_code=0 SET TIMESTAMP=1511948247/*!*/; SET @@session.pseudo_thread_id=33/*!*/; SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/; SET @@session.sql_mode=1436549152/*!*/; SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; SET @@session.lc_time_names=0/*!*/; SET @@session.collation_database=DEFAULT/*!*/; ======================== 在ZST1上执行mysqladmin修改用户密码 ======================== ALTER USER ‘mydba‘@‘192.168.85.%‘ IDENTIFIED WITH ‘mysql_native_password‘ AS ‘*1FA85AA204CC12B39B20E8F1E839D11B3F9E6AA4‘ /*!*/; # at 3443 #171129 17:43:44 server id 1323306 end_log_pos 3508 CRC32 0xfdf414d2 GTID last_committed=14 sequence_number=15 rbr_only=no SET @@SESSION.GTID_NEXT= ‘8ab82362-9c37-11e7-a858-000c29c1025c:69373‘/*!*/; # at 3508 #171129 17:43:44 server id 1323306 end_log_pos 3711 CRC32 0xe72ec7fb Query thread_id=36 exec_time=0 error_code=0 SET TIMESTAMP=1511948624/*!*/; ======================== 在宿主机上执行mysqladmin修改用户密码 ======================== ALTER USER ‘mydba‘@‘192.168.85.1‘ IDENTIFIED WITH ‘mysql_native_password‘ AS ‘*12AB8416B918C0EC1528FD04A686AE12D97A4A5D‘ /*!*/; SET @@SESSION.GTID_NEXT= ‘AUTOMATIC‘ /* added by mysqlbinlog */ /*!*/; DELIMITER ; # End of log file /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/; /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/; [root@ZST1 logs]#
两个ALTER USER对应两次mysqladmin修改用户密码
三、drop user ‘mydba‘，没有指明host，它删除是哪个用户
mydba@192.168.85.132,3306 [(none)]> drop user ‘mydba‘; ERROR 1396 (HY000): Operation DROP USER failed for ‘mydba‘@‘%‘ mydba@192.168.85.132,3306 [(none)]>
根据错误信息，它删除的是用户‘mydba‘@‘%‘
