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Oracle SQL*Plus: The Definitive GuideBy Jonathan Gennick1st Edition March 1999 1-56592-578-5, Order Number: 5785 526 pages, $34.95 |
Sample Chapter 9:
The Product User Profile
In this chapter:
What Is the Product User Profile?
Using 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 DATELONG_VALUE LONGMost 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.
Figure 9-1. The product user profile table, view, and synonyms
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Table 9-1 describes the purpose of each of the element shown in Figure 9-1.
How the Product User Profile Works
Table 9-1: Product User Profile Elements Element
Who Sees It?
Purpose
PRODUCT_PROFILE table
SYSTEM
This is the product user profile table itself.
PRODUCT_USER_PROFILE
private synonym
SYSTEM
Provides backwards compatibility, because the table name used to be PRODUCT_USER_PROFILE.
PRODUCT_PRIVS view
All users
A view that shows each user the restrictions that apply to him or her.
PRODUCT_USER_PROFILE
public synonym
All users
A public synonym pointing to the view.
PRODUCT_PROFILE
public synonym
All users
A public synonym pointing to the view.
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_valueFROM system.product_privsWHERE (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 DISABLEDHOST DISABLEDA 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_valueFROM system.product_privsWHERE (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_ADMINISTRATORHR_ADMINISTRATORThere 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_administratorThis 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_PROFILEWarning: Product user profile information not loaded!You may need to run PUPBLD.SQL as SYSTEMConnected.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.employeeinvalid command: updateThis is all well and good, but the update can easily be coded in PL/SQL. Here's how:
SQL> BEGIN2 UPDATE sqlplus.employee3 SET employee_billing_rate = 3004 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:
- DECLARE
- BEGIN
- EXECUTE
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_rate2 FROM sqlplus.employee;FROM jeff.employee*ERROR at line 2:ORA-00942: table or view does not existSQL> SET ROLE ALL;Role set.SQL> SELECT employee_name, employee_billing_rate2 FROM jeff.employee;EMPLOYEE_NAME EMPLOYEE_BILLING_RATE---------------------------------------- ---------------------Jonathan Gennick 300Jenny Gennick 135Jeff 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_rate2 FROM sqlplus.employee;FROM sqlplus.employee*ERROR at line 2:ORA-00942: table or view does not existSQL> SET ROLE ALL;invalid command: set roleSQL>SQL> DECLARE2 set_role_cursor INTEGER;3 rows_affected INTEGER;4 BEGIN5 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_rate2 FROM sqlplus.employee;EMPLOYEE_NAME EMPLOYEE_BILLING_RATE---------------------------------------- ---------------------Jonathan Gennick 300Jenny Gennick 135Jeff 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:
- Restrict a user, or group of users, from using a specific command.
- Set a role so that it will be disabled for a given user or group of users when SQL*Plus first connects.
- Report the restrictions currently in the profile table.
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.SQLOn 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.sqlIn 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\pupblddrop synonym product_user_profile*ERROR at line 1:ORA-01434: private synonym to be dropped does not existdate_value from product_user_profile*ERROR at line 3:ORA-00942: table or view does not existdrop table product_user_profile*ERROR at line 1:ORA-00942: table or view does not existalter table product_profile add (long_value long)*ERROR at line 1:ORA-00942: table or view does not existTable 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.
Table 9-2: Commands You Can Disable Using the Product User Profile (continued) SQL*Plus
SQL
PL/SQL
CONNECT
ALTER
BEGIN
COPY
ANALYZE
DECLARE
EDIT
AUDIT
EXECUTE
CREATE
EXIT
DELETE
GET
DROP
HOST[1]
GRANT
QUIT
INSERT
PASSWORD
LOCK
RUN
NOAUDIT
SAVE
RENAME
SET[2]
REVOKE
SPOOL
SELECT
START[3]
SET ROLE
SET TRANSACTION
TRUNCATE
UPDATE
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:
DELETEFROM product_profileWHERE 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:
DELETEFROM product_profileWHERE 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 OFFSET PAGESIZE 50SET LINESIZE 60SET NEWPAGE 0SET FEEDBACK OFFSET TRIMSPOOL ONTTITLE LEFT 'Product User Profile Report' -RIGHT 'Page ' FORMAT 9999 SQL.PNO SKIP 6BTITLE OFFCOLUMN userid FORMAT A12 HEADING 'User'COLUMN sort_by NOPRINTCOLUMN command FORMAT A15 HEADING 'Disabled|Commands'COLUMN role FORMAT A30 HEADING 'Disabled|Roles'BREAK ON userid SKIP 1PROMPT 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_FILESET TERMOUT OFFSELECT userid, 1 sort_by, attribute command, '' roleFROM product_profileWHERE product = 'SQL*Plus'AND attribute <> 'ROLES'AND char_value = 'DISABLED'UNIONSELECT userid, 2 sort_by, '' command, char_value roleFROM product_profileWHERE product = 'SQL*Plus'AND attribute = 'ROLES'ORDER BY userid, sort_by, command, role;SPOOL OFFSET TERMOUT ON--Restore these settings to their defaultsTTITLE OFFCLEAR COLUMNSSET PAGESIZE 14SET LINESIZE 80SET NEWPAGE 1SET FEEDBACK ONSET TRIMSPOOL OFFWhen 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_profileYou are about to generate a product user profile report.Enter the filename for the report output: c:\a\profile.lisSQL>When you look in the file, you will see that the report looks like this:
Product User Profile Report Page 1Disabled DisabledUser Commands Roles------------ --------------- ------------------------------GEORGE BEGINDECLAREEXECUTEHR_ADMINISTRATORPAYROLL_ADMINISTRATORJONATHAN BEGINDECLAREDELETEEXECUTEHOSTSET ROLEJEFF HOSTListing 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 OFFSET FEEDBACK OFFSET VERIFY OFFBTITLE OFFSET HEADING OFFSET PAGESIZE 9999SET NEWPAGE 1ACCEPT user_to_show -PROMPT 'Show the product profile for which user? 'TTITLE LEFT restriction_heading SKIP 2COLUMN restriction_type_heading NOPRINT NEW_VALUE restriction_headingCOLUMN sort_by NOPRINTCOLUMN restriction FORMAT A30BREAK ON restriction_type_heading SKIP PAGESELECT 'User ' || UPPER('&&user_to_show')|| ' is restricted from executing the following commands:'restriction_type_heading,1 sort_by, ' ', attribute restrictionFROM product_profileWHERE product = 'SQL*Plus'AND attribute <> 'ROLES'AND char_value = 'DISABLED'AND UPPER('&&user_to_show') LIKE useridUNIONSELECT 'User ' || UPPER('&&user_to_show')|| ' has the following roles disabled:'restriction_type_heading,2 sort_by, ' ', char_value restrictionFROM product_profileWHERE product = 'SQL*Plus'AND attribute = 'ROLES'AND ( UPPER('&&user_to_show') LIKE useridOR userid = 'PUBLIC')UNIONSELECT 'User ' || UPPER('&&user_to_show')|| ' does not exist.'restriction_type_heading,3 sort_by, ' ', ' ' restrictionFROM dualWHERE NOT EXISTS (SELECT usernameFROM all_usersWHERE username = UPPER('&&user_to_show'))ORDER BY sort_by, restriction;--Restore these settings to their defaults.SET HEADING ONSET PAGESIZE 14SET FEEDBACK ONSET VERIFY ONTTITLE OFFCLEAR BREAKSCLEAR COLUMNSThe following example shows how to run the script and what the output looks like:
SQL> @show_product_profileShow the product profile for which user? georgeUser GEORGE is restricted from executing the following commands:BEGINDECLAREEXECUTEUser GEORGE has the following roles disabled:HR_ADMINISTRATORPAYROLL_ADMINISTRATORThe 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_profileShow the product profile for which user? JonathanUser JONATHAN is restricted from executing the following commands:BEGINDECLAREDELETEEXECUTEHOSTSET ROLEUser JONATHAN does not exist.
1. Disabling HOST also disables $, !, or any other operating-system-specific shortcut for executing a host command.
2. 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.
3. Disabling the START command also disables @ and @@.
© 2001, O'Reilly & Associates, Inc.