DOC-4985 added section about restricting privileges

Author: andy-stark-redis

content/integrate/redis-data-integration/data-pipelines/prepare-dbs/oracle.md

@@ -142,7 +142,7 @@ use the following setting:
 }
 ```
 
-## 5. Create a user for the connector
+## 5. Create a user for the connector {#create-dbz-user}
 
 The Debezium Oracle connector must run as an Oracle LogMiner user with
 specific permissions. The following example shows some SQL that creates
@@ -166,39 +166,130 @@ CREATE USER c##dbzuser IDENTIFIED BY dbz
     QUOTA UNLIMITED ON logminer_tbs
     CONTAINER=ALL;
 
-GRANT CREATE SESSION TO c##dbzuser CONTAINER=ALL; 
-GRANT SET CONTAINER TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$DATABASE to c##dbzuser CONTAINER=ALL; 
-GRANT FLASHBACK ANY TABLE TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ANY TABLE TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL; 
-GRANT EXECUTE_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ANY TRANSACTION TO c##dbzuser CONTAINER=ALL; 
-GRANT LOGMINING TO c##dbzuser CONTAINER=ALL; 
-
-GRANT CREATE TABLE TO c##dbzuser CONTAINER=ALL; 
-GRANT LOCK ANY TABLE TO c##dbzuser CONTAINER=ALL; 
-GRANT CREATE SEQUENCE TO c##dbzuser CONTAINER=ALL; 
-
-GRANT EXECUTE ON DBMS_LOGMNR TO c##dbzuser CONTAINER=ALL; 
-GRANT EXECUTE ON DBMS_LOGMNR_D TO c##dbzuser CONTAINER=ALL; 
-
-GRANT SELECT ON V_$LOG TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$LOG_HISTORY TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$LOGMNR_LOGS TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$LOGMNR_CONTENTS TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$LOGMNR_PARAMETERS TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$LOGFILE TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$ARCHIVED_LOG TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$ARCHIVE_DEST_STATUS TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$TRANSACTION TO c##dbzuser CONTAINER=ALL; 
-
-GRANT SELECT ON V_$MYSTAT TO c##dbzuser CONTAINER=ALL; 
-GRANT SELECT ON V_$STATNAME TO c##dbzuser CONTAINER=ALL; 
+GRANT CREATE SESSION TO c##dbzuser CONTAINER=ALL;
+GRANT SET CONTAINER TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$DATABASE to c##dbzuser CONTAINER=ALL;
+
+-- See `Limiting privileges` below if the privileges
+-- granted by these two commands raise security concerns.
+GRANT FLASHBACK ANY TABLE TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ANY TABLE TO c##dbzuser CONTAINER=ALL;
+-- 
+
+GRANT SELECT_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL;
+GRANT EXECUTE_CATALOG_ROLE TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ANY TRANSACTION TO c##dbzuser CONTAINER=ALL;
+GRANT LOGMINING TO c##dbzuser CONTAINER=ALL;
+
+-- See `Limiting privileges` below if the privileges
+-- granted by these two commands raise security concerns.
+GRANT CREATE TABLE TO c##dbzuser CONTAINER=ALL;
+GRANT LOCK ANY TABLE TO c##dbzuser CONTAINER=ALL;
+-- 
+
+GRANT CREATE SEQUENCE TO c##dbzuser CONTAINER=ALL;
+
+GRANT EXECUTE ON DBMS_LOGMNR TO c##dbzuser CONTAINER=ALL;
+GRANT EXECUTE ON DBMS_LOGMNR_D TO c##dbzuser CONTAINER=ALL;
+
+GRANT SELECT ON V_$LOG TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$LOG_HISTORY TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$LOGMNR_LOGS TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$LOGMNR_CONTENTS TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$LOGMNR_PARAMETERS TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$LOGFILE TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$ARCHIVED_LOG TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$ARCHIVE_DEST_STATUS TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$TRANSACTION TO c##dbzuser CONTAINER=ALL;
+
+GRANT SELECT ON V_$MYSTAT TO c##dbzuser CONTAINER=ALL;
+GRANT SELECT ON V_$STATNAME TO c##dbzuser CONTAINER=ALL;
 
 exit;
 ```
 
+### Limiting privileges
+
+The privileges granted in the example above are convenient,
+but you may prefer to restrict them further to improve security. In particular,
+you might want to prevent the Debezium user from creating tables, or
+selecting or locking any table.
+
+The Debezium user needs the `CREATE TABLE` privilege to create the
+`LOG_MINING_FLUSH` and `signals` tables when it connects for the first
+time. After this point, it doesn't need to create any more tables,
+so you can safely revoke this privilege with the following command:
+
+```sql
+REVOKE CREATE TABLE FROM c##dbzuser container=all;
+```
+
+[The example above](#create-dbz-user) grants the `SELECT ANY TABLE` and
+`FLASHBACK ANY TABLE` privileges for convenience, but only the tables synced to RDI,
+the `signals` table, and the `V_$XXX` tables strictly need these privileges.
+You can replace the `GRANT SELECT ANY TABLE` command with explicit
+commands for each table. For example, you would use commands like the
+following for the tables in our sample
+[`chinook`](https://github.com/Redislabs-Solution-Architects/rdi-quickstart-postgres)
+database. (Note that Oracle 19c requires you to run a separate `GRANT`
+command for each table individually.)
+
+```sql
+GRANT SELECT ON signals TO c##dbzuser;
+GRANT SELECT ON chinook.album TO c##dbzuser;
+GRANT SELECT ON chinook.artist TO c##dbzuser;
+GRANT SELECT ON chinook.customer TO c##dbzuser;
+...
+```
+
+Similarly, instead of `GRANT FLASHBACK ANY TABLE`, you would use the following
+commands:
+
+```sql
+GRANT FLASHBACK ON signals TO c##dbzuser;
+GRANT FLASHBACK ON chinook.album TO c##dbzuser;
+GRANT FLASHBACK ON chinook.artist TO c##dbzuser;
+GRANT FLASHBACK ON chinook.customer TO c##dbzuser;
+...
+```
+
+The `LOCK` privilege is automatically granted by the `SELECT`
+privilege, so you can omit this command if you have granted `SELECT`
+on specific tables.
+
+### Revoking existing privileges
+
+If you initially set the Debezium user's privileges on all tables,
+but you now want to restrict them, you can revoke the existing
+privileges before resetting them as described in the
+[Limiting privileges](#limiting-privileges) section.
+
+Use the following commands to revoke and reset the `SELECT` privileges:
+
+```sql
+REVOKE SELECT ANY TABLE FROM c##dbzuser container=all;
+ALTER SESSION SET container=orclpdb1;
+
+GRANT SELECT ON chinook.album TO c##dbzuser;
+-- ...etc
+```
+
+The equivalent commands for `FLASHBACK` are:
+
+```sql
+REVOKE FLASHBACK ANY TABLE FROM c##dbzuser container=all;
+ALTER SESSION SET container=orclpdb1;
+GRANT FLASHBACK ON chinook.album TO c##dbzuser;
+```
+
+The `SELECT` privilege automatically includes the `LOCK`
+privilege, so when you grant `SELECT` for specific tables
+you should also revoke `LOCK` on all tables:
+
+```sql
+REVOKE LOCK ANY TABLE FROM c##dbzuser container=all;
+```
+
 ## 6. Configuration is complete
 
 Once you have followed the steps above, your Oracle database is ready