Oracle SQL*Plus: The Definitive Guide

Chapter 9:The Product User Profile

In addition to the standard database security Oracle provides and enforces for all database objects -- tables, views, and the like -- Oracle also provides an application security scheme for SQL*Plus. This allows you to control the specific commands a SQL*Plus user is allowed to execute. At the core of the SQL*Plus application security scheme is the product user profile.

What Is the Product User Profile?

The product user profile is an Oracle table, owned by the SYSTEM user, that contains a list of SQL*Plus command restrictions by user. The table may contain role restrictions as well. The name of this table used to be PRODUCT_USER_PROFILE. Now it is just PRODUCT_PROFILE, but a synonym named PRODUCT_USER_PROFILE exists to ensure backwards compatibility.

Why Does the Product User Profile Exist?

Primarily, the product user profile enables you to give end users access to SQL*Plus for reporting and ad-hoc query purposes, yet restrict them from using SQL*Plus commands such as INSERT, DELETE, etc., that might damage production data.

Real-world applications typically implement a large number of business rules, edit checks, and even security at the application level rather than within the database. Modifying the data using an ad-hoc tool, such as SQL*Plus, bypasses the rules and puts data integrity at risk. Because of this, it's usually important to ensure that data is modified through the application, where the rules can be enforced.

If you give people an application that requires a database username and password, and those people also have access to SQL*Plus, it won't be too long before some curious and adventurous soul will figure out that the same userid and password that works for the application will also work for SQL*Plus. Next thing you know, you will have someone running ad-hoc queries that haven't been tuned, or, worse yet, you may have someone issuing ad-hoc INSERT, UPDATE, or DELETE commands. The product user profile allows you to defend against this risk.

The PRODUCT_PROFILE Table

The PRODUCT_PROFILE table is owned by SYSTEM and has the following structure:

Name                            Null?    Type 
------------------------------- -------- ---- 
PRODUCT                         NOT NULL VARCHAR2(30) 
USERID                                   VARCHAR2(30) 
ATTRIBUTE                                VARCHAR2(240) 
SCOPE                                    VARCHAR2(240) 
NUMERIC_VALUE                            NUMBER(15,2) 
CHAR_VALUE                               VARCHAR2(240) 
DATE_VALUE                               DATE 
LONG_VALUE                               LONG

Most users will not have SELECT access on the table itself, so if you aren't logged in as SYSTEM, you may not be able to DESCRIBE the table. Instead, you should have access to a view on the table named PRODUCT_PRIVS. This view returns all the records from the PRODUCT_PROFILE table that apply to the currently logged-on user -- you. Figure 9-1 shows the table, the view, the synonyms that normally exist, and the relationship between them.

Table 9-1 describes the purpose of each of the element shown in Figure 9-1.

How the Product User Profile Works

When you log into an Oracle database using SQL*Plus, SQL*Plus will issue two SELECT statements against the product user profile. The first SELECT statement retrieves a list of command restrictions and looks like this:

SELECT attribute, scope,  
      numeric_value, char_value, date_value      
 FROM system.product_privs    
WHERE (UPPER('SQL*Plus') LIKE UPPER(product))  
 AND (UPPER(user) LIKE UPPER(userid))

The two fields of interest to SQL*Plus are ATTRIBUTE and CHAR_VALUE. Together, these columns tell SQL*Plus which commands to disable for the currently logged on user. For example, the following two rows will be returned for a user who has been denied access to the DELETE and HOST commands:

ATTRIBUTE  CHAR_VALUE 
---------- --------------------- 
DELETE     DISABLED 
HOST       DISABLED

A second SELECT statement is issued against the product user profile in order to retrieve any role restrictions for the user. Here's what that statement looks like:

SELECT char_value  
 FROM system.product_privs  
WHERE (UPPER('SQL*Plus') LIKE UPPER(product))  
  AND ( (UPPER(user) LIKE UPPER(userid))  
        OR (UPPER(userid) = 'PUBLIC'))  
  AND (UPPER(attribute) = 'ROLES')

In this case, the CHAR_VALUE column returns a list of roles that are to be disabled whenever the user connects using SQL*Plus. SQL*Plus then disables these roles with a SET ROLE command. By way of example, assume that the following data was returned:

CHAR_VALUE 
--------------------- 
PAYROLL_ADMINISTRATOR 
HR_ADMINISTRATOR

There are two roles to be disabled. SQL*Plus will turn them off by issuing the following command to Oracle:

SET ROLE ALL EXCEPT payroll_administrator, hr_administrator

This establishes the default condition for the user of having those roles turned off. The user may be able to issue another SET ROLE command to turn them back on again, but the starting condition is that the roles are off.

If SQL*Plus's attempt to query the product user profile results in an error, perhaps because the table does not exist, you will see the following message from SQL*Plus:

Error accessing PRODUCT_USER_PROFILE 
Warning:  Product user profile information not loaded! 
You may need to run PUPBLD.SQL as SYSTEM 
Connected.

If you do happen to get the above error message, see the section titled "Creating the Profile Table" later in this chapter, or notify your DBA.

NOTE:  

The SYSTEM user presents a special case. If you log into Oracle as SYSTEM, SQL*Plus detects this, and does not query the product user profile. Therefore, you can never restrict what the SYSTEM user is allowed to do.

Product User Profile Limitations

The product user profile is used for application security. The application is SQL*Plus. No other applications respect the limitations set in the profile. In today's world, with ODBC (Open DataBase Connectivity) on every desktop, and every application under the sun capable of connecting to an Oracle database, securing SQL*Plus should be only a small part of your overall security plan. It is relatively easy for someone with Microsoft Access, for example, to connect to an Oracle database. Once that's done, that user will be able to freely edit, insert, and delete any data to which they have access. Guard against this by implementing as much of your security at the database level as possible.

There are also some potential security "holes" you should be aware of when using the product user profile to secure SQL*Plus. Oracle is a complex product, and often there is more than one way to accomplish any given task. You have to be particularly vigilant about the possible use of PL/SQL. The next two sections describe some known issues to be aware of when setting limits with the product user profile.

Issues related to PL/SQL

Any SQL command you can issue from the SQL*Plus prompt can also be issued from a PL/SQL block. Remember this. It's important. Using the profile, you can restrict a user's access to a SQL command, but it may be possible to get around that restriction with PL/SQL. For this reason, you may want to restrict access to PL/SQL as well.

Take the UPDATE command, for example. Using the profile, you can restrict a SQL*Plus user from issuing the UPDATE command. Should the user try an update, an error will be returned, as the following example shows:

SQL> 
UPDATE sqlplus.employee 
invalid command: update

This is all well and good, but the update can easily be coded in PL/SQL. Here's how:

SQL> 
BEGIN 
 2  
UPDATE sqlplus.employee 
 3     
SET employee_billing_rate = 300 
 4   
WHERE employee_id = 101; 
 5  
END; 
 6  
/  
PL/SQL procedure successfully completed.

That was certainly easy enough, wasn't it? So much for your security. If you need to restrict a user from issuing any INSERT, UPDATE, DELETE, or SELECT commands, you should also restrict the user from using PL/SQL.

Data definition language (DDL) commands, such as GRANT or CREATE TABLE, are a bit more difficult to code from PL/SQL, but they can be done. As long as a user has EXECUTE access to the DBMS_SQL package, you should consider the possibility that the user may be able to code dynamic SQL statements.

NOTE:  

Beginning with Oracle8i, a new version of dynamic SQL is being implemented. This will allow users to code dynamic SQL by simply embedding the desired commands in the PL/SQL block. Thus, the lack of EXECUTE privileges on the DBMS_SQL package won't necessarily stop the user from being able to issue dynamic SQL.

There are two obvious ways to execute PL/SQL from SQL*Plus. One way is to type in a PL/SQL block at the command prompt and execute it. The other way is to use the SQL*Plus EXECUTE command. To restrict a user's access to PL/SQL, you must disable the following three SQL*Plus commands:

Leave any one of the above commands enabled, and you might as well leave them all enabled; the user will still have full access to PL/SQL. There are even less obvious ways to execute PL/SQL, and you may want to guard against these as well. The user could create a stored function and execute that from a SELECT statement, or the user could create a trigger on a table and then fire that trigger. The easiest way to guard against either of these possibilities is to ensure that the user does not have the system privileges required to do these things. An alternative would be to also restrict access to the CREATE command from SQL*Plus.

Issues related to roles

When you disable a role, SQL*Plus turns that role off when the user first connects, but that doesn't prevent the user from turning the role on again. The user can simply issue a SET ROLE command of his own, as the following example shows, turning the desired role back on:

SQL> 
SELECT employee_name, employee_billing_rate 
 2    
FROM sqlplus.employee; 
 FROM jeff.employee 
              * 
ERROR at line 2: 
ORA-00942: table or view does not exist   
SQL> 
SET ROLE ALL;  
Role set.  
SQL> 
SELECT employee_name, employee_billing_rate 
 2    FROM jeff.employee;  
EMPLOYEE_NAME                            EMPLOYEE_BILLING_RATE 
---------------------------------------- --------------------- 
Jonathan Gennick                                           300 
Jenny Gennick                                              135 
Jeff Gennick                                                99 
...

In this example, the first SELECT failed because the PAYROLL_ADMINISTRATOR role had been disabled by SQL*Plus, and consequently the user could not see the EMPLOYEE table. Notice, though, that all the user had to do was issue a SET ROLE ALL command in order to enable the role, allowing him to see the data. It was not even necessary for the user to know the name of the specific role that needed to be enabled. For this reason, disabling the SET ROLE command should usually go hand in hand with disabling roles.

If you've disabled a role for a user, and also disabled the SET ROLE command, you should give some thought to disabling PL/SQL as well. At the very least, you might want to revoke EXECUTE privileges on the DBMS_SQL package. The reason for this is that by using dynamic SQL, the SET ROLE command can be executed from within a PL/SQL block. Admittedly, this would take a very knowledgeable and determined user, but it can be done. Here is an example:

SQL> 
SELECT employee_name, employee_billing_rate 
 2    
FROM sqlplus.employee; 
 FROM sqlplus.employee 
              * 
ERROR at line 2: 
ORA-00942: table or view does not exist   
SQL> 
SET ROLE ALL; 
invalid command: set role 
SQL>  
SQL> 
DECLARE 
 2    
set_role_cursor   INTEGER; 
 3    
rows_affected     INTEGER; 
 4  
BEGIN 
 5    
set_role_cursor := DBMS_SQL.OPEN_CURSOR; 
 6    
DBMS_SQL.PARSE (set_role_cursor, 
 7                    
'SET ROLE payroll_administrator', 
 8                   
DBMS_SQL.NATIVE); 
 9    
rows_affected := DBMS_SQL.EXECUTE(set_role_cursor); 
10   
DBMS_SQL.CLOSE_CURSOR(set_role_cursor); 
11 
END; 
12 
/  
PL/SQL procedure successfully completed.  
SQL> 
SELECT employee_name, employee_billing_rate 
 2    
FROM sqlplus.employee;  
EMPLOYEE_NAME                            EMPLOYEE_BILLING_RATE 
---------------------------------------- --------------------- 
Jonathan Gennick                                           300 
Jenny Gennick                                              135 
Jeff Gennick                                                99 
...

SQL*Plus honors the restriction against using the SET ROLE command from the SQL*Plus prompt, but it has no way of knowing what is going on inside a PL/SQL block. Remember, PL/SQL is sent to the database for execution. SQL*Plus does not look inside a block.

Using the Product User Profile

To use the product user profile, the first thing you need to do is create it. Oracle provides a script for this purpose. Once the product user profile table has been created, there are three things you need to know how to do:

The next few sections show you how to perform each of these tasks.

Creating the Profile Table

Oracle supplies a script named PUPBLD.SQL that creates the table, views, and synonyms shown earlier in this chapter in Figure 9-1. On Windows-based systems, the script can be found in the DBS directory, underneath the Oracle home directory. On Windows NT, the full path and filename for the script is:

C:\ORANT\DBS\PUPBLD.SQL

On Unix systems, the script will be in the SQL*Plus product's admin directory. For example, under HP-UX, and running Oracle 7.3.3, the full path and filename for the script is:

$ORACLE_HOME/sqlplus/admin/pupbld.sql

In some instances, the SQL*Plus directory will be named plusXX instead of sqlplus. The XX in the name represents the Oracle version number, so with Oracle 7.1, the directory would be named plus71.

PUPBLD.SQL should be executed while logged in as user SYSTEM. Executing it while logged in as some other user will result in the profile table being created in the wrong schema, and may also result in a few privilege violations as it tries to create public synonyms. The following example shows the script being executed:

SQL> 
@c:\orant\dbs\pupbld 
drop synonym product_user_profile 
            * 
ERROR at line 1: 
ORA-01434: private synonym to be dropped does not exist   
 date_value from product_user_profile 
                 * 
ERROR at line 3: 
ORA-00942: table or view does not exist   
drop table product_user_profile 
          * 
ERROR at line 1: 
ORA-00942: table or view does not exist   
alter table product_profile add (long_value long) 
* 
ERROR at line 1: 
ORA-00942: table or view does not exist    
Table created. 
View created. 
Grant succeeded. 
Synonym created. 
Synonym created. 
Synonym created. 
Table created. 
Grant succeeded. 
View created. 
Grant succeeded. 
Synonym created. 
0 rows updated. 
SQL>

Do not be alarmed by the error messages. They are nothing to worry about and are simply the result of the way Oracle wrote the script. If you now were to run the script again, you would see a different set of errors. Any errors returned because an object already exists, or because an object does not exist, may safely be ignored.

Limiting Access to Commands

To limit access to a command, you simply need to insert a row into the PRODUCT_PROFILE table. This row tells SQL*Plus which command to disable and for what user. To reenable a command, simply delete the row with the restriction. The following sections show you how to do this.

Commands that can be disabled

There is a specific list of commands that may be disabled using the product user profile. These are listed in Table 9-2.

Disabling a command

To disable a command for a user, insert a row into the PRODUCT_PROFILE table. You should normally log in as SYSTEM, and your INSERT statement should look like this:

INSERT INTO product_profile 
   (product, userid, attribute, char_value) 
   VALUES ('SQL*Plus','
USERNAME','
COMMAND_NAME','DISABLED');

where:

`SQL*Plus'

This is a constant. It identifies the product to which the restriction applies, in this case SQL*Plus. It should always be mixed-case, exactly as shown here.

`USERNAME'

The username of the user you are restricting. It should always be uppercase. You can wildcard this using the wildcard characters that are used with the LIKE predicate, the percent sign and the underscore. A value of `%' would make the restriction apply to all users.

`COMMAND_NAME'

This is the name of the command you wish to disable. It should always be uppercase.

`DISABLED'

The keyword `DISABLED' must be stored in the CHAR_VALUE field.

Fields in the PRODUCT_PROFILE table other than the four listed above are not used by SQL*Plus. They should be left alone, and will default to NULL. The following example will disable the DELETE command for the user named SCOTT:

INSERT INTO product_profile 
   (product, userid, attribute, char_value) 
   VALUES ('SQL*Plus','SCOTT','DELETE','DISABLED');

You can wildcard the USERID field to disable a command for a number of users at once. You can even disable a command across the board for all users. The following statement inserts a row into the PRODUCT_PROFILE table that will disable the SQL*Plus HOST command for everyone:

INSERT INTO product_profile 
   (product, userid, attribute, char_value) 
   VALUES ('SQL*Plus','%','HOST','DISABLED');

Be careful when using wildcards other than %. You have to be sure you know which users you are affecting when you create the restriction, and you have to worry about the possibility that you might create a new username in the future that inadvertently matches some existing restriction. Wildcards also make it difficult to remove a restriction for just one of the users who meet the criteria. For example, you might use "J%" to disable DELETE for all usernames starting with "J". If you later decide that "JONES" needs DELETE access, but "JASON" and "JENNIFER" don't, you have to rethink everything.

Re-enabling a command

To remove a restriction you have created, simply delete that row from the PRODUCT_PROFILE table. For example, to once again allow all users to issue the HOST command, issue the following command:

DELETE  
 FROM product_profile 
WHERE product='SQL*Plus'  
  AND userid='%' 
  AND char_value='HOST'

Limiting Access to Roles

You disable roles for a user in much the same way that you disable commands. The primary reason to disable a role is that a user might have a role for purposes of running an application, but you do not want the user to have that role when issuing ad-hoc commands from SQL*Plus.

Disabling a role

To disable a role for a user, log in as SYSTEM and insert a row into the PRODUCT_PROFILE table, as follows:

INSERT INTO product_profile 
   (product, userid, attribute, char_value) 
   VALUES ('SQL*Plus','
USERNAME','ROLES','
ROLE_NAME');

where:

`SQL*Plus'

Is a constant. It identifies the product to which the restriction applies, in this case SQL*Plus. It should always be mixed-case, exactly as shown here.

`USERNAME'

Is the username of the user you are restricting. It should always be uppercase. You can wildcard the username when restricting a role, but you must be very careful when doing so.

`ROLES'

Instead of a command, the keyword ROLES in this field tells SQL*Plus that you are restricting a role.

`ROLE_NAME'

Is the name of the role to disable.

Fields in the PRODUCT_PROFILE table that are not listed above should be left alone, and will default to NULL. The following example will disable the PAYROLL_ADMINISTRATOR role for the user named SCOTT:

INSERT INTO product_profile 
   (product, userid, attribute, char_value) 
   VALUES ('SQL*Plus','SCOTT','ROLES','PAYROLL_ADMINISTRATOR');

You can wildcard the username when disabling a role, but you must be very careful when doing this. SQL*Plus translates all the role restrictions for a user into a single SET ROLE command like this:

SET ROLE ALL EXCEPT 
role, 
role, 
role...

If any one of those roles is not valid for the user in question, the command will fail and none of the roles will disabled. If you wildcard the username when disabling a role, you must be absolutely certain either that each user has been granted the role in question, or that the role has been granted to PUBLIC.

Re-enabling a role

The method for removing a role restriction is the same as that used to remove a command restriction -- delete the row from the PRODUCT_PROFILE table. For example, to allow SCOTT to be a PAYROLL_ADMINISTRATOR when logged in using SQL*Plus, issue the following DELETE command:

DELETE  
 FROM product_profile 
WHERE product='SQL*Plus'  
  AND userid='SCOTT' 
  AND command='ROLES' 
  AND char_value='PAYROLL_ADMINISTRATOR'

You normally need to be logged in as SYSTEM to delete from the PRODUCT_PROFILE table.

Reporting on the Product User Profile

The following sections show you two different ways to look at the product user profile. The first section provides a script you can run to generate a report showing all the restrictions currently defined in the PRODUCT_PROFILE table. The second section provides a script that will show you the restrictions for a particular user, which you can specify.

You should run these scripts while logged in as the SYSTEM user. If you run them while logged in as anyone else, you will see only the restrictions that apply to you.

Listing all restrictions

The following script will generate a report showing all the command and role restrictions defined in the PRODUCT_PROFILE table:

SET ECHO OFF 
SET PAGESIZE 50 
SET LINESIZE 60 
SET NEWPAGE 0 
SET FEEDBACK OFF 
SET TRIMSPOOL ON  
TTITLE LEFT 'Product User Profile Report' - 
      RIGHT 'Page ' FORMAT 9999 SQL.PNO SKIP 6 
BTITLE OFF   
COLUMN userid FORMAT A12 HEADING 'User' 
COLUMN sort_by NOPRINT  
COLUMN command FORMAT A15 HEADING 'Disabled|Commands' 
COLUMN role FORMAT A30 HEADING 'Disabled|Roles'  
BREAK ON userid SKIP 1  
PROMPT You are about to generate a product user profile report. 
ACCEPT PUP_REPORT_FILE - 
      PROMPT 'Enter the filename for the report output: ' - 
      DEFAULT 'PUP_REPORT.LIS'  
SPOOL &&PUP_REPORT_FILE 
SET TERMOUT OFF  
SELECT userid, 1 sort_by, attribute command, '' role 
 FROM product_profile 
WHERE product = 'SQL*Plus' 
  AND attribute <> 'ROLES' 
  AND char_value = 'DISABLED' 
UNION 
SELECT userid, 2 sort_by, '' command, char_value role  
 FROM product_profile 
WHERE product = 'SQL*Plus' 
  AND attribute = 'ROLES' 
ORDER BY userid, sort_by, command, role 
;  
SPOOL OFF 
SET TERMOUT ON  
--Restore these settings to their defaults 
TTITLE OFF 
CLEAR COLUMNS 
SET PAGESIZE 14 
SET LINESIZE 80 
SET NEWPAGE 1 
SET FEEDBACK ON 
SET TRIMSPOOL OFF

When you run the script, you will be prompted for a filename, and the report output will be sent to that file. Here's an example showing how to run the script:

SQL> 
@report_product_profile 
You are about to generate a product user profile report. 
Enter the filename for the report output: c:\a\profile.lis 
SQL>

When you look in the file, you will see that the report looks like this:

Product User Profile Report                       Page     1      
            Disabled        Disabled 
User         Commands        Roles 
------------ --------------- ------------------------------ 
GEORGE       BEGIN 
            DECLARE 
            EXECUTE 
                            HR_ADMINISTRATOR 
                            PAYROLL_ADMINISTRATOR  
JONATHAN     BEGIN 
            DECLARE 
            DELETE 
            EXECUTE 
            HOST 
            SET ROLE  
JEFF         HOST

Listing restrictions for a particular user

To find out what restrictions apply to any one user, you must keep in mind that the USERID field in the PRODUCT_PROFILE table may contain wildcards. The following script will prompt you for a username, then display a list of all the disabled commands and roles for that user. The queries involved use the LIKE operator to account for any possible wildcards.

SET ECHO OFF 
SET FEEDBACK OFF 
SET VERIFY OFF  
BTITLE OFF 
SET HEADING OFF 
SET PAGESIZE 9999 
SET NEWPAGE 1  
ACCEPT user_to_show - 
      PROMPT 'Show the product profile for which user? '  
TTITLE LEFT restriction_heading SKIP 2 
COLUMN restriction_type_heading NOPRINT NEW_VALUE restriction_heading 
COLUMN sort_by NOPRINT 
COLUMN restriction FORMAT A30 
BREAK ON restriction_type_heading SKIP PAGE  
SELECT 'User ' || UPPER('&&user_to_show') 
      || ' is restricted from executing the following commands:' 
      restriction_type_heading, 
      1 sort_by, '    ', attribute restriction 
 FROM product_profile 
WHERE product = 'SQL*Plus' 
  AND attribute <> 'ROLES' 
  AND char_value = 'DISABLED' 
  AND UPPER('&&user_to_show') LIKE userid 
UNION 
SELECT 'User ' || UPPER('&&user_to_show')  
      || ' has the following roles disabled:' 
      restriction_type_heading, 
      2 sort_by, '    ', char_value restriction 
 FROM product_profile 
WHERE product = 'SQL*Plus' 
  AND attribute = 'ROLES' 
  AND ( UPPER('&&user_to_show') LIKE userid 
        OR userid = 'PUBLIC') 
UNION 
SELECT 'User ' || UPPER('&&user_to_show') 
      || ' does not exist.' 
      restriction_type_heading, 
      3 sort_by, '    ', ' ' restriction 
 FROM dual 
WHERE NOT EXISTS ( 
         SELECT username  
           FROM all_users 
          WHERE username = UPPER('&&user_to_show')) 
ORDER BY sort_by, restriction 
;  
--Restore these settings to their defaults. 
SET HEADING ON 
SET PAGESIZE 14 
SET FEEDBACK ON 
SET VERIFY ON 
TTITLE OFF 
CLEAR BREAKS 
CLEAR COLUMNS

The following example shows how to run the script and what the output looks like:

SQL> 
@show_product_profile 
Show the product profile for which user? 
george  
User GEORGE is restricted from executing the following commands:  
    BEGIN 
    DECLARE 
    EXECUTE  
User GEORGE has the following roles disabled:  
    HR_ADMINISTRATOR 
    PAYROLL_ADMINISTRATOR

The script will even tell you whether or not the user really exists. It is possible to create entries in the PRODUCT_PROFILE table for users who do not exist. It is also possible to drop a user, leaving orphan entries in the profile. The following example demonstrates this:

SQL> 
@show_product_profile 
Show the product profile for which user? 
Jonathan  
User JONATHAN is restricted from executing the following commands:  
    BEGIN 
    DECLARE 
    DELETE 
    EXECUTE 
    HOST 
    SET ROLE  
User JONATHAN does not exist.

Disabling HOST also disables $, !, or any other operating-system-specific shortcut for executing a host command.

Disabling the SET command takes SET ROLE and SET TRANSACTION with it. That's because SQL*Plus simply looks at the first word to see if it matches the entry in the profile table.

Disabling the START command also disables @ and @@.

-- End of Chapter 9 --