【动手实践】：Lockdown Profile 的多租户权限控制
在Oracle Database 12.2 中引入了lockdown profile的新特性，可以用于限制PDB中的某些操作，增强某些操作的安全性。
PDB Lockdown Profiles to Restrict Operations on PDBs Starting with this release, in a multitenant environment, you can use PDB lockdown profiles to restrict functionality available to users in a given PDB. PDB lockdown profiles enable you to restrict the access the user has to a set of features individually or in a group. This feature is designed to enhance security for situations in which identities are shared among PDBs.
以下通过一个简单的测试来看看这个特性的基本功能。 首先在CDB下创建一个profile，这个Profile将对全局可用：
SQL> connect / as sysdba
Connected.
SQL> CREATE LOCKDOWN PROFILE enmotech;
Lockdown Profile created.
SQL> ALTER LOCKDOWN PROFILE enmotech DISABLE STATEMENT = ('ALTER SYSTEM');
Lockdown Profile altered.连接到PDB YHEM,在PDB级别启用lockdown profile :
SQL> connect sys/oracle@yhem as sysdba
Connected.
SQL> ALTER SYSTEM SET PDB_LOCKDOWN = enmotech;
System altered.测试一下，可以看到所有的ALTER SYSTEM的操作都被禁用了：
SQL> alter system checkpoint;
alter system checkpoint
*
ERROR at line 1:
ORA-01031: insufficient privileges
SQL> alter system set optimizer_mode = first_rows_1;
alter system set optimizer_mode = first_rows_1
*
ERROR at line 1:
ORA-01031: insufficient privilegesLOCKDOWN PROFILE可以限制到非常细粒度的权限，比如以下限制仅仅限制用户执行ARCHIVE LOG和CHECKPOINT操作。
SQL> connect / as sysdba
Connected.
SQL> alter lockdown profile enmotech enable statement = ('ALTER SYSTEM')
2 clause all except = ('ARCHIVE LOG', 'CHECKPOINT');
Lockdown Profile altered.现在测试一下，可以看到在PDB上，限制精确的生效，CHECKPOINT操作不允许被执行：
SQL> connect system/oracle@yhem
Connected.
SQL> alter system set optimizer_mode = first_rows_1;
System altered.
SQL> alter system checkpoint;
alter system checkpoint
*
ERROR at line 1:
ORA-01031: insufficient privileges除了特定的权限，还可以对某些数据库功能特点进行限制，比如调用和执行UTL_HTTP 和 UTL_TCP 包可能是高风险的，那么以下的PROFILE设置可以禁用这些特性：
SQL> alter lockdown profile enmotech
2 disable feature = ('UTL_HTTP', 'UTL_TCP');
Lockdown profile altered.
SQL> conn system/oracle@yhem
Connected.
SQL> declare
2 l_request utl_http.req;
3 l_response utl_http.resp;
4 begin
5 l_request := utl_http.begin_request('http://www.enmotech.com');
6 l_response := utl_http.get_response(l_request);
7 end;
8/
declare
*
ERROR at line 1:
ORA-29273: HTTP request failed
ORA-01031: insufficient privileges
ORA-06512: at "SYS.UTL_HTTP", line 380
ORA-06512: at "SYS.UTL_HTTP", line 1127
ORA-06512: at line 5