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postgresql影子用户实践场景分析

程序员文章站 2022-06-23 11:06:39
在实际的生产环境 ,我们经常会碰到这样的情况:因为业务场景需要,本部门某些重要的业务数据表需要给予其他部门查看权限,因业务的扩展及调整,后期可能需要放开更多的表查询权限。为解决此种业务需求,我们可以采...

在实际的生产环境 ,我们经常会碰到这样的情况:因为业务场景需要,本部门某些重要的业务数据表需要给予其他部门查看权限,因业务的扩展及调整,后期可能需要放开更多的表查询权限。为解决此种业务需求,我们可以采用创建视图的方式来解决,已可以通过创建影子用户的方式来满足需求,本文主要介绍影子用户的创建及授权方法。

场景1:只授予usage on schema 权限

session 1:
--创建readonly用户,并将test模式赋予readonly用户。

postgres=# create user readonly with password 'postgres';
create role
postgres=# grant usage on schema test to readonly;
​grant
postgres=# \dn
list of schemas
 name | owner 
-------+-------
 test | postgres

session 2:

--登陆readonly用户可以查询test模式下现存的所有表。

postgres=# \c postgres readonly 
you are now connected to database "postgres" as user "readonly".
postgres=> select * from test.emp ;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno 
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | allen | salesman | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | ward  | salesman | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | jones | manager  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | martin | salesman | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | blake | manager  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | clark | manager  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | king  | president |   | 1981-11-17 | 5000.00 |     |   10
 7844 | turner | salesman | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | james | clerk   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | ford  | analyst  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | miller | clerk   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | analyst  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | adams | clerk   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | smith | clerk   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

换到session 1创建新表t1

postgres=# create table test.t1 as select * from test.emp;
​create table

切换到session 2 readonly用户下,t1表无法查询

postgres=> select * from test.t1 ;
2021-03-02 15:25:33.290 cst [21059] error: permission denied for table t1
2021-03-02 15:25:33.290 cst [21059] statement: select * from test.t1 ;
**error: permission denied for table t1

结论:如果只授予 usage on schema 权限,readonly 只能查看 test 模式下已经存在的表和对象。在授予 usage on schema 权限之后创建的新表无法查看。

场景2:授予usage on schema 权限之后,再赋予 select on all tables in schema 权限

针对上个场景session 2 **error: permission denied for table t1 错误的处理

postgres=> select * from test.t1 ;
**error: permission denied for table t1

session 1: 使用postgres用户授予readonly用户 select on all tables 权限

postgres=# grant select on all tables in schema test to readonly ;

session 2: readonly用户查询 t1 表

postgres=> select * from test.t1;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno 
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | allen | salesman | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | ward  | salesman | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | jones | manager  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | martin | salesman | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | blake | manager  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | clark | manager  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | king  | president |   | 1981-11-17 | 5000.00 |     |   10
 7844 | turner | salesman | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | james | clerk   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | ford  | analyst  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | miller | clerk   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | analyst  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | adams | clerk   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | smith | clerk   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

session1 :postgres用户的test模式下创建新表 t2

postgres=# create table test.t2 as select * from test.emp;
select 14

session 2:readonly用户查询 t2 表权限不足

postgres=> select * from test.t2 ;
error: permission denied for table t2

session 1:再次赋予 grant select on all tables

postgres=# grant select on all tables in schema test to readonly ;

session 2:readonly用户又可以查看 t2 表

postgres=> select * from test.t2 ;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno 
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | allen | salesman | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | ward  | salesman | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | jones | manager  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | martin | salesman | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | blake | manager  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | clark | manager  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | king  | president |   | 1981-11-17 | 5000.00 |     |   10
 7844 | turner | salesman | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | james | clerk   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | ford  | analyst  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | miller | clerk   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | analyst  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | adams | clerk   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | smith | clerk   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

影子用户创建

如果想让readonly只读用户不在每次 postgres用户在test模式中创建新表后都要手工赋予 grant select on all tables in schema test to readonly 权限。则需要授予对test默认的访问权限,对于test模式新创建的也生效。

session 1:未来访问test模式下所有新建的表赋权,创建 t5 表。

postgres=# alter default privileges in schema test grant select on tables to readonly ;
alter default privileges
postgres=# create table test.t5 as select * from test.emp;
create table

session 2:查询readonly用户

postgres=> select * from test.t5;
 empno | ename |  job  | mgr | hiredate |  sal  | comm  | deptno 
-------+--------+-----------+------+------------+---------+---------+--------
 7499 | allen | salesman | 7698 | 1981-02-20 | 1600.00 | 300.00 |   30
 7521 | ward  | salesman | 7698 | 1981-02-22 | 1250.00 | 500.00 |   30
 7566 | jones | manager  | 7839 | 1981-04-02 | 2975.00 |     |   20
 7654 | martin | salesman | 7698 | 1981-09-28 | 1250.00 | 1400.00 |   30
 7698 | blake | manager  | 7839 | 1981-05-01 | 2850.00 |     |   30
 7782 | clark | manager  | 7839 | 1981-06-09 | 2450.00 |     |   10
 7839 | king  | president |   | 1981-11-17 | 5000.00 |     |   10
 7844 | turner | salesman | 7698 | 1981-09-08 | 1500.00 |  0.00 |   30
 7900 | james | clerk   | 7698 | 1981-12-03 | 950.00 |     |   30
 7902 | ford  | analyst  | 7566 | 1981-12-03 | 3000.00 |     |   20
 7934 | miller | clerk   | 7782 | 1982-01-23 | 1300.00 |     |   10
 7788 | test  | analyst  | 7566 | 1982-12-09 | 3000.00 |     |   20
 7876 | adams | clerk   | 7788 | 1983-01-12 | 1100.00 |     |   20
 1111 | smith | clerk   | 7902 | 1980-12-17 | 800.00 |     |   20
(14 rows)

总结:影子用户创建的步骤

--创建影子用户
create user readonly with password 'postgres';
--将schema中usage权限赋予给readonly用户,访问所有已存在的表
grant usage on schema test to readonly;
grant select on all tables in schema test to readonly;
--未来访问test模式下所有新建的表
alter default privileges in schema test grant select on tables to readonly ;

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相关标签: postgresql 影子