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From "Rick Hillegas (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-5968) A failed connection attempt may nevertheless manage to boot the database.
Date Thu, 08 Nov 2012 19:20:12 GMT

    [ https://issues.apache.org/jira/browse/DERBY-5968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13493412#comment-13493412
] 

Rick Hillegas commented on DERBY-5968:
--------------------------------------

I have linked this issue to DERBY-2407 which also addresses the topic of accidentally booted
databases. Discussion there notes that Derby would consume even more CPU if it deliberately
brought down the database after an accidental boot and that, in turn, would make a denial-of-service
attack consume more CPU. I think that there is a tradeoff between that denial-of-service-attack
and the current denial-of-service attack of consuming memory by leaving an accidentally booted
database up and running. And I don't think that either attack is likely or worth worrying
about.

More seriously, DERBY-2407 discusses race conditions which could arise when more than one
user tries to boot the database by connecting to it. We would want to make sure that shutting
down after an accidental boot didn't orphan other users who are racing us to connect. DERBY-4447
might give us the tools to do this.

I am halting work on this issue. Before proceeding further, I think we would want to:

1) Implement DERBY-4447 so that we have a clean mechanism for handling connection races.

2) Clean up the replication api so that we can remove the hack in derby-5968-01-ac-shutdownDatabaseIfBootingConnectionFails.diff.
                
> A failed connection attempt may nevertheless manage to boot the database.
> -------------------------------------------------------------------------
>
>                 Key: DERBY-5968
>                 URL: https://issues.apache.org/jira/browse/DERBY-5968
>             Project: Derby
>          Issue Type: Bug
>          Components: Services
>    Affects Versions: 10.10.0.0
>            Reporter: Rick Hillegas
>         Attachments: derby-5968-01-aa-shutdownDatabaseIfBootingConnectionFails.diff,
derby-5968-01-ab-shutdownDatabaseIfBootingConnectionFails.diff, derby-5968-01-ac-shutdownDatabaseIfBootingConnectionFails.diff
>
>
> A connection attempt may fail but still manage to boot the database. If possible, we
should try to bring down the database after the connection failure.
> 1) Here is an example of this problem: If you use bad credentials to connect to a database,
you will fail to get a connection. That's correct behavior. However, Derby must boot the database
in order to discover its authentication mechanism. The database remains booted after this
check.
> 2) There are other examples of this problem. For instance, if a user with good credentials
tries to change the boot password on an encrypted database, then the connection attempt will
fail, but the database will remain booted. This can cause silent failures on later attempts
to re-encrypt or un-encrypt a database after the low-privilege or nonexistent user manages
to boot the database. The connection attempt will succeed, leading the DBO to think that the
re-encryption worked. But actually re-encryption did not take place because the database was
already booted.
> I regard this silent failure as a security vulnerability.
> The following script shows problem (1):
> connect 'jdbc:derby:db;create=true;user=test_dbo';
> call syscs_util.syscs_create_user( 'test_dbo', 'test_dbopassword' );
> -- shutdown the database
> connect 'jdbc:derby:db;shutdown=true';
> -- need credentials in order to get a connection
> connect 'jdbc:derby:db';
> connect 'jdbc:derby:db;user=test_dbo;password=test_dbopassword';
> select count(*) from sys.systables;
> -- shutdown the database
> connect 'jdbc:derby:db;shutdown=true;user=test_dbo;password=test_dbopassword';
> -- try to shutdown the database again. since it is already shutdown, you will get a message
saying it can't be found.
> connect 'jdbc:derby:db;shutdown=true;user=test_dbo;password=test_dbopassword';
> -- now try to boot with bad credentials. you don't get a connection but the database
boots.
> connect 'jdbc:derby:db;user=alice;password=alicepassword;bootPassword=foobarwibblewombat';
> select count(*) from sys.systables;
> -- the shutdown command succeeds because alice managed to boot the database
> -- even though she isn't a legal user.
> connect 'jdbc:derby:db;shutdown=true;user=test_dbo;password=test_dbopassword';

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