Authenticator will not work in Kiosk situations because of assumptions

Name: mc57594 Date: 01/08/2000


java version "1.3beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3beta-O)
Java(TM) HotSpot Client VM (build 1.3beta-O, mixed mode)


When setting up a multi-user Kiosk for a web-browser-like application, it would
be nice to be able to "restart" the authentication. For instance, if one kiosk
user provides a username and password to access a restricted file on a remote
web server, the Authenticator retains that username and password and tries to
use it for the next URLConnection to the same web page. This allows a
subsequent user to gain access to the first users pages without typing a
password. I would like to be able to tell the Authenticator to reset its
internal state and not try to reuse the username and password. Right now, that
is impossible, without restarting the Java VM.

My application allows a user A to go to a web server and retrieve a number of
pages in her own realm. When another user B walks up to the kiosk, that user is
asked for his password only if the authentication didn't work. If user B
decides to look at user A's documents instead of his own, he is never asked for
a username and password. URLConnection automatically uses the username and
password already acquired from an Authenticator without asking user B or giving
the application a chance to deny access.

Right now there is no way to invalidate an authenticator and log someone out
from their basic authentication.

The workaround is set up my own password system that asks for a password when
user A logs out.


Example code:

      if (sess != null)
sess.setDefaultAuthenticator(); // Installs new Authenticator.

      System.out.println("Connecting to "+userURL);
      URLConnection UC = userURL.openConnection();
      System.out.println("Auth request prop: "+UC.getRequestProperty
("Authorization"));
      UC.setRequestProperty("Authorization", "Basic ABCD"); // Garbage
      System.out.println("Auth request pro2: "+UC.getRequestProperty
("Authorization"));
      long fileMod = UC.getLastModified();
      System.out.println("Auth request pro3: "+UC.getRequestProperty
("Authorization"));

Result (for user B trying to look at user A's web pages):

Connecting to http://salmon.crc.ricoh.com:8001/barrus/lists/mdates.sorted
Auth request prop: null
Auth request pro2: Basic ABCD
Auth request pro3: Basic bWVubG86YnJ1Y2U=


Notice that even though I have tried to set the request property to make the
URLConnection fail and call the Authenticator, the request property is changed
inside the call to UC.getLastModified() to the most recently used
username:password and the Authenticator is never called. (When my Authenticator
is called, it prints out a line indicating that it has been called and that
didn't happen above.)

I have also tried clearing the password character array as suggested in the
Authentication documentation and that doesn't make any difference.

The only thing that does work is to go to another realm and let the
authenticator fail (return an invalid username:password) and then the
Authenticator asks you again for your password when you return to your own
realm.

How about a routine that clears out the hidden Authentication cache so that the
Authenticator gets called again next time a 401 is returned from a
URLConnection? This would solve my problem.
(Review ID: 99674)
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