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We have an application in our organization that is based on Oracle Forms 11g (on Oracle Fusion Middleware/WLS). Users have access to the application through accounts created at the database (i.e. they exist in dba_users). Each user is assigned a specific role based on their area of work and they use the user id to log on to the application. The user may have read/write access to certain functionality in the application and for this their roles have the following permissions-

EXECUTE ANY LIBRARY   
SELECT  ANY SEQUENCE   
EXECUTE ANY TYPE      
EXECUTE ANY PROCEDURE 
UPDATE  ANY TABLE      
SELECT  ANY TABLE      
DELETE  ANY TABLE      
EXECUTE ANY INDEXTYPE 
INSERT  ANY TABLE  

Now we have some users requesting for SQL Client access (i.e. TNS settings) so that they can connect to the DB and perform queries for their research. These business users are ofcourse knowledgeable in SQL but we want to restrict their access based on the type of client they use to log on to the database. Any client other than the application itself, should restrict them to "read only".

Is there a way to achieve this?

  • Not possible. The name of the client is provided by the client itself - so the client can pretend to be sqlplus or sqldeveloper or annjawan. You have to restrict this through the user account, it's the only safe way. – a_horse_with_no_name Feb 27 '15 at 0:03
  • But we know the Application client's name. Can we restrict it like if not <app_client> then... perhaps through a BEFORE LOGON trigger? We also know the Machine Name which will always be the Application server name if the user is using the Application, that can be used as well? – Annjawn Feb 27 '15 at 0:09
  • I can connect with a different client pretending to be <app_client> without any problems. You can also change the value that shows up in machine in v$session (those are simply connection properties for a JDBC connection for example). You might be able to check the IP address in a logon trigger, but I'm not sure about that. The only (really: the only) safe way to restrict access is through privileges on the user account. – a_horse_with_no_name Feb 27 '15 at 0:19
  • Yes, I figured that is the only safe way but revoking access privilege will mean revoke privileges from the application too, which we don't want to do. I don't think the users are that smart to be changing their connection properties ;) but the question is will a BEFORE LOGON trigger with revoke command work? – Annjawn Feb 27 '15 at 0:28
  • The only way to do this is to create separate read-only users. A given user cannot have two seperate sets of grants. – Philᵀᴹ Feb 27 '15 at 7:59
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You can check it with a database trigger, for example:

CREATE ROLE ROLE_POWER_USER NOT IDENTIFIED;

CREATE OR REPLACE TRIGGER LOG_T_LOGON 
    AFTER LOGON ON DATABASE
DECLARE

    osUser VARCHAR2(30);
    machine VARCHAR2(100); 
    prog VARCHAR2(100)
    ip VARCHAR2(15);

BEGIN

    IF ora_login_user IS NULL THEN 
        RETURN;
    END IF;

    SELECT OSUSER, MACHINE, PROGRAM, ora_client_ip_address
    INTO osUser, machine, prog, ip
    FROM V$SESSION 
    WHERE SID = SYS_CONTEXT('USERENV', 'SID');

    IF NOT DBMS_SESSION.IS_ROLE_ENABLED('ROLE_POWER_USER') THEN     
        IF LOWER(prog) <> 'your_application_name.exe' THEN
            RAISE_APPLICATION_ERROR(-20000, 'Logon denied: You must use only the official client application');
        END IF;
    ELSE
        IF LOWER(prog) NOT IN ('sqlplus.exe', 'toad.exe') THEN
            RAISE_APPLICATION_ERROR(-20000, 'Logon denied: You must use only SQL*Plus or TOAD for you private queries');
        END IF; 
    END IF;
    -- Successful login, continue as normal
END;
/

You can also check other conditions like IP-Address or the machine name.

SELECT privileges on tables and views you have to grant to the user or ROLE in the "classic" way. This trigger only prevents to logon to the database with certain tools.

Note, a user with System Privilege ADMINISTER DATABASE TRIGGER (for example DBA role, or SYS of course) never get the exception, i.e. they can logon to the database in any case and you cannot block this by the trigger.

Another note: This trigger is not 100% secure. For example you can simply make a copy of your local sqlplus.exe and name it your_application_name.exe. Then this trigger would allow to use it.

  • I don't need to make a copy of sqlplus.exe to connect using your_application_name.exe. In a JDBC client this is a simple configuration property (so is machine name or OS user) – a_horse_with_no_name Feb 27 '15 at 13:21
  • @wernfried This trigger worked pretty nicely. We did some changes to it to include checking the user PROFILE and instead of checking the program we check the MACHINE from where the conncection is coming from. Our Application always connects from the App Server Machine id even when User logs on to the app from their PC and that server machine id will not change (ever). So that solves the program name problem. – Annjawn Mar 9 '15 at 19:52

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