5 Configuring Rule Sets

Creating a New Rule

To create and add a rule to a rule set:

1. In the Oracle Database Vault Administration page, select Rule Sets.

2. In the Rule Sets page, select the rule set to which you want to create and add a rule, and then select Edit.

3. In the Edit Rule Set Page, scroll down to Rules Associated To The Rule Set and select Create.

4. In the Create Rule page, enter the following settings:

   • Name: Enter a name for the rule. Use up to 90 characters in mixed-case.

     Oracle suggests that you start the name with a verb and complete the name with the purpose of the rule. For example:

     Prevent non-admin access to SQL*Plus
     

     Because rules do not have a Description field, make the name explicit but be sure to not exceed over 90 characters.

   • Rule Expression: Enter a PL/SQL expression that fits the following requirements:

     • It is valid in a SQL WHERE clause.

     • It can be a freestanding and valid PL/SQL Boolean expression such as the following:

       TO_CHAR(SYSDATE,'HH24') = '12'
       

     • It must evaluate to a Boolean (TRUE or FALSE) value.

     • It must be no more than 255 characters long.

     • It can contain existing and compiled PL/SQL functions from the current database instance. Ensure that these are fully qualified functions (such as schema. function_name). Do not include complete SQL statements.

       If you want to use application package functions or standalone functions, you must grant the DVSYS account the EXECUTE privilege on the function. Doing so reduces the chances of errors when you add new rules.

     • Ensure that the rule works. You can test the syntax by running the following statement in SQL*Plus:

       SELECT rule_expression FROM DUAL;
       

       For example, suppose you have created the following the rule expression:

       SYS_CONTEXT('USERENV','SESSION_USER') != 'TSMITH'
       

       You could test this expression as follows:

       SELECT SYS_CONTEXT('USERENV','SESSION_USER') FROM DUAL;
       

     See the following sections for functions that you can use in the rule set expression:

     • "Oracle Database Vault PL/SQL Rule Functions"

     • Chapter 12, "Using the DVSYS.DBMS_MACADM Package"

     • Chapter 14, "Using the DVSYS.DBMS_MACUTL Package"

     For additional examples of expressions, see the rule defined in the rule sets provided with Oracle Database Vault. "Default Rule Sets" lists these rule sets.

5. Click OK.

   The Edit Rule Set page appears. By default, the new rule is added to the rule set.

Editing a Rule

The changes you make to a rule apply to all rule sets that include the rule.

To edit a rule:

1. In the Edit Rule Set page, scroll to Rules Associated To The Rule Set.

2. Select the rule you want to edit and click Edit.

3. In the Edit Rule page, modify the rule as necessary.

4. Click OK.

Removing a Rule from a Rule Set

Before you remove a rule from a rule set, you can locate the various references to it by querying the rules-related Oracle Database Vault views. See "Oracle Database Vault Data Dictionary Views" for more information.

To remove a rule from a rule set:

1. In the Edit Rule Set page, scroll to Rules Associated To The Rule Set.

2. Select the rule you want to delete and click Remove.

3. In the Confirmation page, click Yes.

After you remove the rule from the rule set, it still exists. If you want, you can associate it with other rule sets. If you want to delete the rule, use the DVSYS.DBMS_MACADM.DELETE_RULE function, described in "Rule Set Procedures Within DVSYS.DBMS_MACADM". For example, to delete the rule Night Shift, log in to SQL*Plus as the Database Vault Owner and enter the following statement:

EXEC DVSYS.DBMS_MACADM.DELETE_RULE('Night Shift');

Adding Existing Rules to a Rule Set

To add existing rules to a rule set:

1. In the Rule Sets page, select the rule set that you want to add rules to, and then select Edit.

2. Under Rules Associated To The Rule Set, select Add Existing Rules.

3. In the Add Existing Rules page, select the rules you want, and then click Move (or Move All, if you want all of them) to move them to the Selected Rules list.

   You can select multiple rules by holding down the Ctrl key as you click each rule.

4. Click OK.

How Oracle Database Vault Evaluates Rules

Oracle Database Vault evaluates the rules within a rule set as a collection of expressions. If you have set Evaluation Options to All True and if a rule fails the evaluation, then the evaluation stops at that point, instead of attempting to evaluate the rest of the rules in the rule set. Similarly, if Evaluation Options is set to Any True and if a rule evaluates to true, the evaluation stops at that point. If a rule set is disabled, Oracle Database Vault evaluates it to true without evaluating its rules.

Nesting Rules Within a Rule Set

You can nest one or more rules within the rule set. For example, suppose you want to create a nested rule, Is Corporate Network During Maintenance, that performs the following two tasks:

• It limits table modifications only when the database session originates within the corporate network.

• It restricts table modifications during the system maintenance window scheduled between 10:00 p.m. and 10:59 p.m.

The rule definition would be as follows:

DVF.F$NETWORK = 'Corporate' AND TO_CHAR(SYSDATE,'HH24') between '22' AND '23'

You can create it using a factor function. See "Oracle Database Vault PL/SQL Factor Functions" for more information. Chapter 7 explains how to create factors.

Creating Rules to Apply to Everyone Except One User

You can also create rules to apply to everyone except one user (for example, a privileged user). The rule definition for this type of rule can be as follows:

SYS_CONTEXT('USERENV','SESSION_USER') = 'SUPERADMIN_USER' OR additional_rule

If the current user is a privileged user, then the system evaluates the rule to true without evaluating additional_rule. If the current user is not a privileged user, then the evaluation of the rule depends on the evaluation of additional_rule.

About This Tutorial

In the following tutorial, you create an e-mail alert that is sent when a user attempts to alter a table outside a maintenance period. To do this, you must create a rule to set the maintenance period hours, attach this rule to a rule set, and then create a command rule to allow the user to alter the table. You then associate the rule set with this command rule, which then sends the e-mail alert when the user attempts to use the ALTER TABLE SQL statement outside the maintenance period.

Step 1: Install and Configure the UTL_MAIL PL/SQL Package

1. Log in to SQL*Plus as SYS using the SYSDBA privilege, and then install the UTL_MAIL package.

   sqlplus sys as sysdba
   Enter password: password
   
   @$ORACLE_HOME/rdbms/admin/utlmail.sql
   @$ORACLE_HOME/rdbms/admin/prvtmail.plb
   

   The UTL_MAIL package enables you to manage e-mail. See Oracle Database PL/SQL Packages and Types Reference for more information about UTL_MAIL. However, be aware that currently, the UTL_MAIL PL/SQL package do not support SSL servers.

2. Check the current value of the SMTP_OUT_SERVER parameter, and make a note of this value so that you can restore it when you complete this tutorial.

   For example:

   SHOW PARAMETER SMTP_OUT_SERVER
   

   Output similar to the following appears:

   NAME                    TYPE              VALUE
   ----------------------- ----------------- ----------------------------------
   SMTP_OUT_SERVER         string            some_value.example.com
   

3. Issue the following ALTER SYSTEM statement:

   ALTER SYSTEM SET SMTP_OUT_SERVER="imap_mail_server.example.com";
   

   Replace imap_mail_server.example.com with the name of your SMTP server, which you can find in the account settings in your e-mail tool. Enclose these settings in quotation marks. For example:

   ALTER SYSTEM SET SMTP_OUT_SERVER="my_imap_mail_server.example.com"
   

4. Connect as SYS using the SYSOPER privilege and then restart the database.

   CONNECT SYS/AS SYSOPER
   Enter password: password
   
   SHUTDOWN IMMEDIATE
   STARTUP
   

5. Ensure that the SMTP_OUT_SERVER parameter setting is correct.

   CONNECT SYS/AS SYSDBA
   Enter password: password
   
   SHOW PARAMETER SMTP_OUT_SERVER
   

   Output similar to the following appears:

   NAME                    TYPE              VALUE
   ----------------------- ----------------- ----------------------------------
   SMTP_OUT_SERVER         string            my_imap_mail_server.example.com
   

Step 2: Create an E-Mail Security Alert PL/SQL Procedure

1. Ensure that you are connected as SYS using the SYSDBA privilege, and then grant the following privileges to a user who has been granted the DV_OWNER role.

   (Alternatively, you can select a user who has been granted the DV_ADMIN role, but for this tutorial, you will select a user who has the DV_OWNER role.)

   For example:

   CONNECT SYS/AS SYSDBA
   Enter password: password
   
   GRANT CREATE PROCEDURE, DROP ANY PROCEDURE TO lbrown_dvowner;
   GRANT EXECUTE ON UTL_TCP TO lbrown_dvowner;
   GRANT EXECUTE ON UTL_SMTP TO lbrown_dvowner;
   GRANT EXECUTE ON UTL_MAIL TO lbrown_dvowner;
   GRANT EXECUTE ON DBMS_NETWORK_ACL_ADMIN TO lbrown_dvowner;
   

   The UTL_TCP, UTL_SMTP, UTL_MAIL, and DBMS_NETWORK_ACL_ADMIN PL/SQL packages will be used by the e-mail security alert that you create.

2. Connect to SQL*Plus as the DV_OWNER user.

   For example:

   CONNECT lbrown_dvowner
   Enter password: password
   

3. Create the following procedure:

   CREATE OR REPLACE PROCEDURE email_alert AS
   msg varchar2(20000) := 'Realm violation occurred for the ALTER TABLE Command Security Policy rule set. The time is: '; 
   BEGIN
     msg := msg||to_char(SYSDATE, 'Day DD MON, YYYY HH24:MI:SS'); 
   UTL_MAIL.SEND (
       sender      => 'youremail@example.com',
       recipients  => 'recipientemail@example.com',
       subject     => 'Table modification attempted outside maintenance!',
       message     => msg); 
   END email_alert;
   /
   

   Replace youremail@example.com with your e-mail address, and recipientemail@example.com with the e-mail address of the person you want to receive the notification.

4. Grant the EXECUTE permission on this procedure to DVSYS.

   GRANT EXECUTE ON email_alert TO DVSYS; 
   

Step 3: Configure an Access Control List File for Network Services

Before you can use PL/SQL network utility packages such as UTL_MAIL, you must configure an access control list (ACL) file that enables fine-grained access to external network services. For detailed information about this topic, see Oracle Database Security Guide.

To configure an access control list for the e-mail alert:

1. As the DV_OWNER user, in SQL*Plus, create the following access control list and its privilege definitions.

   BEGIN
    DBMS_NETWORK_ACL_ADMIN.CREATE_ACL (
     acl          => 'mail_server_permissions.xml', 
     description  => 'Enables network permissions for the mail server',
     principal    => 'LBROWN_DVOWNER',
     is_grant     => TRUE, 
     privilege    => 'connect');
   END;
   /
   

   Ensure that you enter your exact user name for the principal setting, in upper-case letters. For this tutorial, enter the name of the Database Vault Owner account (for example, LBROWN_DVOWNER).

2. Assign the access control list to the outgoing SMTP network host for your e-mail server.

   BEGIN
    DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL (
     acl         => 'mail_server_permissions.xml',
     host        => 'SMTP_OUT_SERVER_setting', 
     lower_port  => port); 
   END;
   /
   

   In this example:

   • SMTP_OUT_SERVER_setting: Enter the SMTP_OUT_SERVER setting that you set for the SMTP_OUT_SERVER parameter in "Step 1: Install and Configure the UTL_MAIL PL/SQL Package". This setting should match exactly the setting that your e-mail tool specifies for its outgoing server.

   • port: Enter the port number that your e-mail tool specifies for its outgoing server. Typically, this setting is 25. Enter this value for both the lower_port and upper_port settings. (Currently, the UTL_MAIL package does not support SSL. If your mail server is an SSL server, then enter 25 for the port number, even if the mail server uses a different port number.)

3. Commit your changes to the database.

   COMMIT;
   

4. Test the settings that you have created so far.

   EXEC EMAIL_ALERT;
   COMMIT;
   

   SQL*Plus should display a PL/SQL procedure successfully completed message, and in a moment, depending on the speed of your e-mail server, you should receive the e-mail alert.

   If you receive an ORA-24247: network access denied by access control list (ACL) error followed by ORA-06512: at stringline string errors, then check the settings in the access control list file.

Step 4: Create a Rule Set and a Command Rule to Use the E-Mail Security Alert

1. As the DV_OWNER user, create the following rule set:

   BEGIN
    DVSYS.DBMS_MACADM.CREATE_RULE_SET(
     rule_set_name    => 'ALTER TABLE Command Security Policy', 
     description      => 'This rule set allows ALTER TABLE only during the 
                          maintenance period.', 
     enabled          => 'Y',
     eval_options     => 1,
     audit_options    => DBMS_MACUTL.G_RULESET_AUDIT_FAIL,,
     fail_options     => DBMS_MACUTL.G_RULESET_FAIL_SILENT,
     fail_message     => '',
     fail_code        => NULL,
     handler_options  => DBMS_MACUTL.G_RULESET_HANDLER_FAIL,
     handler          => 'dbavowner.email_alert');
   END;
   /
   

2. Create a rule similar to the following.

   For now, set the rule expression to be during the time you test it. For example, if you want to test it between 2 p.m. and 3 p.m., create the rule as follows:

   BEGIN
    DVSYS.DBMS_MACADM.CREATE_RULE(
     rule_name  => 'Restrict Access to Maintenance Period', 
     rule_expr  => 'TO_CHAR(SYSDATE,''HH24'') BETWEEN ''14'' AND ''15''');
   END;
   /
   

   Ensure that you use two single quotation marks instead of double quotation marks for HH24, 14, and 15.

   You can check the system time on your computer by issuing the following SQL statement:

   SELECT TO_CHAR(SYSDATE,'HH24') FROM DUAL;
   

   Output similar to the following appears:

   TO
   --
   14
   

   Later on, when you are satisfied that the rule works, you can update it to a time when your site typically performs maintenance work (for example, between 7 p.m. and 10 p.m), as follows:

   BEGIN
    DVSYS.DBMS_MACADM.UPDATE_RULE(
     rule_name  => 'Restrict Access to Maintenance Period', 
     rule_expr  => 'TO_CHAR(SYSDATE,''HH24'') BETWEEN ''19'' AND ''22''');
   END;
   /
   

3. Add the Restrict Access to Maintenance Period rule to the ALTER TABLE Command Security Policy rule set.

   BEGIN
    DBMS_MACADM.ADD_RULE_TO_RULE_SET(
     rule_set_name => 'ALTER TABLE Command Security Policy', 
     rule_name     => 'Restrict Access to Maintenance Period'); 
   END;
   /
   

4. Create the following command rule:

   BEGIN
    DVSYS.DBMS_MACADM.CREATE_COMMAND_RULE(
     command         => 'ALTER TABLE', 
     rule_set_name   => 'ALTER TABLE Command Security Policy', 
     object_owner    => 'SCOTT', 
     object_name     => '%', 
     enabled         => 'Y');
   END; 
   /
   

5. Commit these updates to the database.

   COMMIT;
   

Step 5: Test the E-Mail Security Alert

1. Connect to SQL*Plus as user SCOTT.

   For example:

   CONNECT SCOTT
   Enter password: password
   

   If the SCOTT account is locked and expired, then a user with the DV_ACCTMGR role can unlock this account and create a new password as follows:

   ALTER USER SCOTT ACCOUNT UNLOCK IDENTIFIED BY password;
   

   Replace password with a password that is secure. See Oracle Database Security Guide for the minimum requirements for creating passwords.

2. As the user SCOTT, create a test table.

   CREATE TABLE mytest (col1 number);
   

3. Change the system time on your computer to a time when the ALTER TABLE Command Security Policy rule set takes place.

   For example, if you set the test period time to between 2 p.m. and 3 p.m., do the following:

   UNIX: Log in as root and use the date command to set the time. For example, assuming the date today is December 13, 2007, you would enter the following:

   $ su root
   Password: password
   
   $ date 12131409
   

   Windows: Double-click the clock icon, which is typically at the lower right corner of the screen. In the Date and Time Properties window, set the time to 2 p.m., and then click OK.

4. Try altering the my_test table.

   ALTER TABLE mytest ADD (col2 number);
   
   Table altered.
   

   SCOTT should be able to alter the mytest table during this time.

5. Reset the system time to a time outside the Restrict Access to Maintenance Period time.

6. Log in as SCOTT and try altering the my_test table again.

   CONNECT SCOTT
   Enter password: password
   
   ALTER TABLE mytest ADD (col3 number);
   

   The following output should appear:

   ORA-47400: Command Rule violation for ALTER TABLE on SCOTT.MYTEST
   

   SCOTT cannot alter the mytest table. In a moment, you should receive an e-mail with the subject header Table modification attempted outside maintenance! and with a message similar to the following:

   Realm violation occurred for the ALTER TABLE Command Security Policy rule set. The time is: Wednesday 06 MAY, 2009 14:24:25
   

7. Reset the system time to the correct time.

Step 6: Remove the Components for This Tutorial

1. Connect to SQL*Plus as the DV_OWNER user, and then in the order shown, drop the Oracle Database Vault rule components.

   EXEC DVSYS.DBMS_MACADM.DELETE_RULE_FROM_RULE_SET('ALTER TABLE Command Security Policy', 'Restrict Access to Maintenance Period');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE('Restrict Access to Maintenance Period');
   EXEC DVSYS.DBMS_MACADM.DELETE_COMMAND_RULE('ALTER TABLE', 'SCOTT', '%');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE_SET('ALTER TABLE Command Security Policy');
   

2. Drop the email_alert PL/SQL procedure.

   DROP PROCEDURE email_alert;
   

3. Remove the access control list.

   EXEC DBMS_NETWORK_ACL_ADMIN.DROP_ACL ('email_alert_permissions.xml');
   

4. Connect as user SCOTT and remove the mytest table.

   CONNECT SCOTT
   Enter password: password
   
   DROP TABLE mytest;
   

5. Connect as SYS using the SYSDBA privilege and then revoke the EXECUTE privilege on the UTL_TCP, UTL_SMTP, and UTL_MAIL PL/SQL packages from the DV_OWNER user.

   For example:

   REVOKE EXECUTE ON UTL_TCP FROM lbrown_dvowner;
   REVOKE EXECUTE ON UTL_SMTP FROM lbrown_dvowner;
   REVOKE EXECUTE ON UTL_MAIL FROM lbrown_dvowner;
   REVOKE EXECUTE ON DBMS_NETWORK_ACL_ADMIN from lbrown_dvowner;
   

6. Set the SMTP_OUT_SERVER parameter to its original value.

   For example:

   ALTER SYSTEM SET SMTP_OUT_SERVER="some_value.example.com";
   

7. Connect as SYS using the SYSOPER privilege and then restart the database.

   CONNECT SYS/AS SYSOPER
   Enter password: password
   
   SHUTDOWN IMMEDIATE
   STARTUP
   

About This Tutorial

In this tutorial, you configure a rule set that defines two-person integrity (TPI), also called dual key security, dual key connection, and two-man rule security. In this type of security, two users are required to authorize an action instead of one user. The idea is that one user provides a safety check for the other user before that user can proceed with a task. Two-person integrity provides an additional layer of security for actions that potentially can be dangerous. This type of scenario is often used for tasks such as database patch updates, which is what this tutorial will demonstrate. One user, patch_user must log in to perform a database patch upgrade, but the only way that he can do this is if his manager, patch_boss is already logged in. You will create a function, rules, a rule set, and a command rule to control patch_user's ability to log in.

Step 1: Create Users for This Tutorial

You must create the following two users for this tutorial:

• patch_boss acts in a supervisory role: If patch_boss is not logged in, then the patch_user user cannot log in.

• patch_user is the user who is assigned to perform the patch upgrade. However, for this tutorial, user patch_user does not actually perform a patch upgrade. He only attempts to log in.

To create the users:

1. Connect to SQL*Plus as a user who has been granted the DV_ACCTMGR role.

   For example:

   CONNECT amalcolm_dvacctmgr
   Enter password: password
   

2. Create the following users.

   CREATE USER PATCH_BOSS IDENTIFIED BY password;
   CREATE USER PATCH_USER IDENTIFIED BY password;
   

   Replace password with a password that is secure. See Oracle Database Security Guide for the minimum requirements for creating passwords.

3. Connect as user SYS with the SYSDBA privilege and grant privileges to the following users.

   CONNECT SYS/AS SYSDBA
   Enter password: password
   
   GRANT CREATE PROCEDURE TO lbrown_dvowner;
   GRANT SELECT ON V_$SESSION TO lbrown_dvowner;
   GRANT CREATE SESSION TO PATCH_BOSS;
   GRANT CREATE SESSION TO PATCH_USER;
   

In a real-world scenario, you also would log in as the DV_OWNER user and grant the DV_PATCH_ADMIN role to user patch_user (but not to patch_boss). But because you are not really going to perform a database patch upgrade in this tutorial, you do not need to grant this role to user patch_user.

Step 2: Create a Function to Check if User patch_boss Is Logged In

The function that you must create, check_boss_logged_in, does just that: When user patch_user tries to log in to SQL*Plus, it checks if user patch_boss is already logged in by querying the V$SESSION data dictionary view.

To create the check_boss_logged_in function:

1. Connect to SQL*Plus as a user who has been granted the DV_OWNER or DV_ADMIN role.

   For example:

   CONNECT lbrown_dvowner
   Enter password: password
   

2. Create the check_boss_logged_in function as follows:

   CREATE OR REPLACE FUNCTION check_boss_logged_in
   return varchar2
   authid current_user as 
    
   v_session_number number := 0;
   v_allow varchar2(10)    := 'TRUE';
   v_deny varchar2(10)     := 'FALSE';
    
   BEGIN
     SELECT COUNT(*) INTO v_session_number
     FROM SYS.V_$SESSION
     WHERE USERNAME = 'PATCH_BOSS'; -- Enter the user name in capital letters.
    
    IF v_session_number > 0
     THEN RETURN v_allow;
    ELSE
     RETURN v_deny;
    END IF;
   END check_boss_logged_in;
   /
   

3. Grant the EXECUTE privilege on the check_boss_logged_in function to the DVSYS schema.

   GRANT EXECUTE ON check_boss_logged_in to DVSYS;
   

Step 3: Create Rules, a Rule Set, and a Command Rule to Control the Users' Access

Next, you must create two rules, a rule set to which you will add them, and a command rule. The rule set triggers the check_boss_logged_in function when user patch_user tries to logs in to the database.

To create the rules and rule set:

1. Create the Check if Boss Is Logged In rule, which checks that the patch_user user is logged in to the database.

   If the check_boss_logged_in function returns TRUE (that is, patch_boss is logged in to another session), then patch_user can log in.

   BEGIN
     DVSYS.DBMS_MACADM.CREATE_RULE(
     rule_name => 'Check if Boss Is Logged In',
     rule_expr => 'SYS_CONTEXT(''USERENV'',''SESSION_USER'') = ''PATCH_USER'' and LBROWN_DVOWNER.check_boss_logged_in =  ''TRUE'' ');
   END;
   /
   

   Enter the user name, PATCH_USER, in upper-case letters, which is how the SESSION_USER parameter stores it.

2. Create the Allow Connect for Other Database Users rule, which ensures that the user logged in (patch_user) is not user patch_boss. It also enables all other valid users to log in.

   BEGIN
    DVSYS.DBMS_MACADM.CREATE_RULE(
     rule_name => 'Allow Connect for Other Database Users',
     rule_expr => 'SYS_CONTEXT(''USERENV'',''SESSION_USER'') != ''PATCH_USER''');
   END;
   /
   COMMIT;
   

3. Create the Dual Connect for Boss and Patch rule set, and then add the two rules to it.

   BEGIN
        DVSYS.DBMS_MACADM.CREATE_RULE_SET(
        rule_set_name => 'Dual Connect for Boss and Patch',
        description => 'Checks if both boss and patch users are logged in.',
        enabled           => 'Y',
        eval_options      => 2,
        audit_options     => DBMS_MACUTL.G_RULESET_AUDIT_FAIL,
        fail_options      => DBMS_MACUTL.G_RULESET_FAIL_SILENT,
        fail_message      =>'',
        fail_code         => NULL,
        handler_options   => DBMS_MACUTL.G_RULESET_HANDLER_OFF,
        handler           => ''
        );
   END;
   /
   
   BEGIN
        DVSYS.DBMS_MACADM.ADD_RULE_TO_RULE_SET(
        rule_set_name     => 'Dual Connect for Boss and Patch',
        rule_name         => 'Check if Boss Is Logged In'
      );
   END;
   /
   
   BEGIN
        DVSYS.DBMS_MACADM.ADD_RULE_TO_RULE_SET(
        rule_set_name     => 'Dual Connect for Boss and Patch',
        rule_name         => 'Allow Connect for Other Database Users'
      );
   END;
   /
   

4. Create the following CONNECT command rule, which permits user patch_user to connect to the database only if patch_boss is already logged in.

   BEGIN
      DVSYS.DBMS_MACADM.CREATE_COMMAND_RULE(
      command             => 'CONNECT',
       rule_set_name      => 'Dual Connect for Boss and Patch',
       object_owner       => '%',
       object_name        => '%',
       enabled            => 'Y');
   END;
   /
   COMMIT;
   

Step 4: Test the Users' Access

1. Try to connect to SQL*Plus as user patch_user.

   CONNECT patch_user
   Enter password: password
   
   ERROR:
   ORA-47400: Command Rule violation for CONNECT on LOGON
   

   User patch_user cannot log in until user patch_boss is already logged in.

2. Open a second shell and then log in as user patch_boss.

   sqlplus patch_boss
   Enter password: password
   Connected. 
   

   User patch_boss can log in.

3. Go back to the first shell, and then try logging in as user patch_user again.

   sqlplus patch_user
   Enter password: password
   

   This time, user patch_user is deemed a valid user, so now he can log in.

Step 5: Remove the Components for This Tutorial

1. In the session for the user patch_boss, exit SQL*Plus and then close the shell.

   EXIT
   

2. In the first shell, connect the DV_ACCTMGR user and remove the users you created.

   CONNECT amalcolm_dvacctmgr
   Enter password: password
   
   DROP USER patch_boss;
   DROP USER patch_user;
   

3. Connect as the DV_OWNER or DV_ADMIN user and drop the check_boss_logged_in function, the rules, rule set, and command rule, in the order shown.

   CONNECT lbrown_dvowner
   Enter password: password
   
   DROP FUNCTION check_boss_logged_in;
   EXEC DVSYS.DBMS_MACADM.DELETE_COMMAND_RULE('CONNECT', '%', '%');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE_FROM_RULE_SET('Dual Connect for Boss and Patch', 'Check if Boss Is Logged In');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE_FROM_RULE_SET('Dual Connect for Boss and Patch', 'Allow Connect for Other Database Users');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE('Check if Boss Is Logged In');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE('Allow Connect for Other Database Users');
   EXEC DVSYS.DBMS_MACADM.DELETE_RULE_SET('Dual Connect for Boss and Patch');
   COMMIT;
   

4. Connect as user SYS with the SYSDBA privilege and revoke the following privileges from the DV_OWNER or DV_ADMIN user.

   CONNECT SYS/AS SYSDBA
   Enter password: password
   
   REVOKE CREATE PROCEDURE FROM lbrown_dvowner;
   REVOKE SELECT ON V_$SESSION FROM lbrown_dvowner;