在Oracle Database 12.2 中引入了lockdown profile的新特性，可以用於限制PDB中的某些操作，增強某些操作的安全性。

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.

以下通過一個簡單的測試來看看這個特性的基本功能。 首先在CDB下建立一個profile，這個Profile將對全域性可用：

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.

連線到PDB YHEM,在PDB級別啟用lockdown profile :

SQL> connect sys/oracle@yhem as sysdba
Connected.
SQL> ALTER SYSTEM SET PDB_LOCKDOWN = enmotech;
System altered.

測試一下，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 privileges
 

LOCKDOWN PROFILE可以限制到非常細粒度的許可權，比如以下限制僅僅限制使用者執行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.

現在測試一下，可以看到在PDB上，限制精確的生效，CHECKPOINT操作不允許被執行：

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

除了特定的許可權，還可以對某些資料庫功能特點進行限制，比如呼叫和執行UTL_HTTP 和 UTL_TCP 包可能是高風險的，那麼以下的PROFILE設定可以禁用這些特性：

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