--连接数据库时,host和user的匹配规则
官方文档:https://dev.mysql.com/doc/refman/5.7/en/connection-access.html
--host和user的匹配规则如下:
--是host为明确的最先匹配,host带%模糊的时候最后匹配,但host为''(空)位于%之后才匹配
--相同的host时候,比较user为明确的最先匹配,user为''(空)最后匹配
--相同的host和user时,排序是不确定的
When multiple matches are possible, the server must determine which of them to use. It resolves this issue as follows: Whenever the server reads the user table into memory, it sorts the rows. When a client attempts to connect, the server looks through the rows in sorted order. The server uses the first row that matches the client host name and user name. The server uses sorting rules that order rows with the most-specific Host values first. Literal host names and IP addresses are the most specific. (The specificity of a literal IP address is not affected by whether it has a netmask, so 198.51.100.13 and 198.51.100.0/255.255.255.0 are considered equally specific.) The pattern '%' means “any host” and is least specific. The empty string '' also means “any host” but sorts after '%'. Rows with the same Host value are ordered with the most-specific User values first (a blank User value means “any user” and is least specific). For rows with equally-specific Host and User values, the order is nondeterministic.
--查看当前的host及用户信息匹配顺序,先host顺序匹配、后user顺序匹配
mysql> SELECT authentication_string, host, user,account_locked FROM mysql.USER ORDER BY host desc ,user desc; +-------------------------------------------+--------------+---------------+----------------+ | authentication_string | host | user | account_locked | +-------------------------------------------+--------------+---------------+----------------+ | *511C0A408C5065XXEC90D60YYA1AB9437281AF28 | localhost | root | N | | *THISISNOTAVALIXXASSWORDYYATCANBEUSEDHERE | localhost | mysql.sys | Y | | *THISISNOTAVALIXXASSWORDYYATCANBEUSEDHERE | localhost | mysql.session | Y | | *485CE31BA547A4XXC047659YY10DF200F361CD4E | localhost | bkpuser | N | | *7B502777D8FF69XX4B56BC2YY2867F4B47321BA8 | 192.168.56.% | repl | N | | *AECCE73463829AXX3968838YYF6F85E43C3F169C | % | flyremote | N | | *566AC8467DAAAEXXE247AE7YY0A770E9B97D9FB0 | | flylocal | N | +-------------------------------------------+--------------+---------------+----------------+ 8 rows in set (0.00 sec)
--举个特殊例子
--建立两个特殊用户如下,一个用户名为''(空)、一个用户名和host都为''(空)
mysql> create user ''@'localhost' identified by "Kong123$"; Query OK, 0 rows affected (0.00 sec) mysql> create user ''@'' identified by "doubleKong123$"; Query OK, 0 rows affected (0.00 sec)
--查看当前的host及用户信息匹配顺序,先host顺序匹配、后user顺序匹配
mysql> SELECT authentication_string, host, user,account_locked FROM mysql.USER ORDER BY host desc ,user desc; +-------------------------------------------+--------------+---------------+----------------+ | authentication_string | host | user | account_locked | +-------------------------------------------+--------------+---------------+----------------+ | *511C0VVV8C5065CBEC90D6TTTT1AB9437281AF28 | localhost | root | N | | *THISIVVVTAVALIDPASSWORTTTTTCANBEUSEDHERE | localhost | mysql.sys | Y | | *THISIVVVTAVALIDPASSWORTTTTTCANBEUSEDHERE | localhost | mysql.session | Y | | *485CEVVVA547A48CC04765TTTT0DF200F361CD4E | localhost | bkpuser | N | | *256D7VVV91F7363EBDADEFTTTTB74B2B318746FC | localhost | | N | | *7B502VVVD8FF69164B56BCTTTT867F4B47321BA8 | 192.168.56.% | repl | N | | *AECCEVVV63829A5F396883TTTT6F85E43C3F169C | % | flyremote | N | | *566ACVVV7DAAAE79E247AETTTTA770E9B97D9FB0 | | flylocal | N | | *AE162VVV68403D1D98A4C9TTTT50A508B8C56F3F | | | N | +-------------------------------------------+--------------+---------------+----------------+ 9 rows in set (0.00 sec)
--这样本地登录flyremote用户时 会报错,因为按以上的顺序 优先匹配到了host为localhost、user为''(空)的用户,而不是flyremote用户 (因为user为''(空)的用户可以匹配任意用户名)
[root@hostmysql-m mysql]# mysql -uflyremote -pFlyremote123$ mysql: [Warning] Using a password on the command line interface can be insecure. ERROR 1045 (28000): Access denied for user 'flyremote'@'localhost' (using password: YES)
--那就是说本地登录flyremote用户时, 用匹配到的host为localhost、user为''(空)的密码 Kong123$ ,就可以正常登陆了
[root@hostmysql-m mysql]# mysql -uflyremote -pKong123$ mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 15 Server version: 5.7.23-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. 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.
--查看当前用户连接方式 和 当前用户认证方式
mysql> select user(),CURRENT_USER(); +---------------------+----------------+ | user() | CURRENT_USER() | +---------------------+----------------+ | flyremote@localhost | @localhost | +---------------------+----------------+ 1 row in set (0.06 sec)
--用带入ip的方式登录flyremote用户时 无问题, ip匹配到了% ,user匹配到了flyremote
[root@hostmysql-m mysql]# mysql -uflyremote -pFlyremote123$ -h127.11.22.33 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 12 Server version: 5.7.23-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. 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>
--查看当前用户连接方式 和 当前用户认证方式
mysql> select user(),CURRENT_USER(); +------------------------+----------------+ | user() | CURRENT_USER() | +------------------------+----------------+ | flyremote@127.11.22.33 | flyremote@% | +------------------------+----------------+ 1 row in set (0.00 sec)
--任意用户、任意host,只要密码和建立的第二个空用户空host的密码"doubleKong123$"匹配了, 就可以进入mysql
--测试一个不存在的用户hahaha
[root@hostmysql-m ~]# mysql -uhahaha -pdoubleKong123$ -h127.11.22.33 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 6 Server version: 5.7.23-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. 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>
--查看当前用户连接方式 和 当前用户认证方式
mysql> select user(),CURRENT_USER(); +---------------------+----------------+ | user() | CURRENT_USER() | +---------------------+----------------+ | hahaha@127.11.22.33 | @ | +---------------------+----------------+ 1 row in set (0.01 sec)
--解决方案:
1、手工删除空用户和空host用户确保安全
或者
2、使用 mysql_secure_installation 来进行安全配置
--安全配置如下,其中有删除匿名用户的操作
This program enables you to improve the security of your MySQL installation in the following ways: You can set a password for root accounts. You can remove root accounts that are accessible from outside the local host. You can remove anonymous-user accounts. You can remove the test database (which by default can be accessed by all users, even anonymous users), and privileges that permit anyone to access databases with names that start with test_.
--删除匿名用户的源码 mysql_secure_installation.cc 如下:
//Remove anonymous users remove_anonymous_users(); /** Removes all the anonymous users for better security. */ void remove_anonymous_users() { int reply; reply= get_response((const char *) "By default, a MySQL installation has an " "anonymous user,\nallowing anyone to log " "into MySQL without having to have\na user " "account created for them. This is intended " "only for\ntesting, and to make the " "installation go a bit smoother.\nYou should " "remove them before moving into a production\n" "environment.\n\nRemove anonymous users" "(Press y|Y for Yes, any other key for No) : ", 'y'); if (reply == (int) 'y' || reply == (int) 'Y') { const char *query; query= "SELECT USER, HOST FROM mysql.user WHERE USER=''"; if (!execute_query(&query, strlen(query))) DBUG_PRINT("info", ("query success!")); MYSQL_RES *result= mysql_store_result(&mysql); if (result) drop_users(result); mysql_free_result(result); fprintf(stdout, "Success.\n\n"); } else fprintf(stdout, "\n ... skipping.\n\n"); }
补充:mysql 用户表中多个host时的匹配规则
mysql数据库中user表的host字段,是用来控制用户访问数据库“权限”的。
可以使用“%”,表示所有的网段;
也可以使用具体的ip地址,表示只有该ip的客户端才可以登录到mysql服务器;
也可以使用“_”进行模糊匹配,表示某个网段的客户端可以登录到mysql服务器。
如果在user表中存在一个用户两条不同host值的记录,那么mysql服务器该如何匹配该用户的权限呢?
mysql采用的策略是:当服务器读取user表时,它首先以最具体的Host值排序(主机名和IP号是最具体的) 。有相同Host值的条目首先以最具体的User匹配。
举例:
如下,有两条root用户,那么只有localhost的root客户端可以登录到mysql服务器。
| root | localhost | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | | root | % | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B |
以上为个人经验,希望能给大家一个参考,也希望大家多多支持。如有错误或未考虑完全的地方,望不吝赐教。
《魔兽世界》大逃杀!60人新游玩模式《强袭风暴》3月21日上线
暴雪近日发布了《魔兽世界》10.2.6 更新内容,新游玩模式《强袭风暴》即将于3月21 日在亚服上线,届时玩家将前往阿拉希高地展开一场 60 人大逃杀对战。
艾泽拉斯的冒险者已经征服了艾泽拉斯的大地及遥远的彼岸。他们在对抗世界上最致命的敌人时展现出过人的手腕,并且成功阻止终结宇宙等级的威胁。当他们在为即将于《魔兽世界》资料片《地心之战》中来袭的萨拉塔斯势力做战斗准备时,他们还需要在熟悉的阿拉希高地面对一个全新的敌人──那就是彼此。在《巨龙崛起》10.2.6 更新的《强袭风暴》中,玩家将会进入一个全新的海盗主题大逃杀式限时活动,其中包含极高的风险和史诗级的奖励。
《强袭风暴》不是普通的战场,作为一个独立于主游戏之外的活动,玩家可以用大逃杀的风格来体验《魔兽世界》,不分职业、不分装备(除了你在赛局中捡到的),光是技巧和战略的强弱之分就能决定出谁才是能坚持到最后的赢家。本次活动将会开放单人和双人模式,玩家在加入海盗主题的预赛大厅区域前,可以从强袭风暴角色画面新增好友。游玩游戏将可以累计名望轨迹,《巨龙崛起》和《魔兽世界:巫妖王之怒 经典版》的玩家都可以获得奖励。
更新日志
- 群星《歌手2024 第4期》[FLAC/分轨][563.76MB]
- RiffKitten-ChaosParade(2024)[24-44,1]FLAC
- RuneKlakegg-Nattevandrer(2024)[24-96]\FLAC
- 赖冰霞.2006-金嗓典藏辑2IN1(南方金点系列)2CD【南方】【WAV+CUE】
- 群星.1988-国语金曲尽精英VOL.2【瑞成】【WAV+CUE】
- 张宇.1999-雨一直下【EMI百代】【WAV+CUE】
- 袁娅维.2021-月亮失眠了(DELUXE)【华纳】【FLAC分轨】
- AlanBroadbent-JazzFunk(2024)[24-44,1]
- 梅艳芳《绝代芳华》开盘母带[低速原抓WAV+CUE]
- ABC唱片-《外国精逊母带直刻神奇黑胶[APE+CUE].
- 群星《天赐的声音第五季 第6期》[320K/MP3][101.43MB]
- 群星《天赐的声音第五季 第6期》[FLAC/分轨][526.16MB]
- 群星《说唱梦工厂 第2期》[320K/MP3][96.37MB]
- 杨宗宪.1994-留你留袂着【有容唱片】【WAV+CUE】
- 李翊君.2005-勇敢的爱【创意唱片】【WAV+CUE】