IZ22782: SUBSCRIPTION FAILS WITH NULLPOINTEREXCEPTION AFTER BIP7025W WARNING

WebSphere Message Broker V6.1 - Fix Pack 6.1.0.7

APAR status

• Closed as program error.

Error description

• What appears to be the problem is that before adding the
  subscription, the topic permissions are checked against the
  subscriber. When the permission check fails with the BIP7025W,
  the subscription record is not added to the BSUBSCRIPTIONS table
  but the code continues and adds a record to the BCLIENTUSER
  table and a SubNameSubscription to the internal SubName table,
  if Sub Names are being used.
  
  The nullpointer exception occurs when a subsequent subscription
  for the same client and sub name is registered. The subname
  record is found and it is assumed that a subscription exists
  when in fact it doesn't.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere Message Broker v6.0   *
  *                 using publish subscribe and the              *
  *                 UserNameServer for topic security.           *
  ****************************************************************
  * PROBLEM DESCRIPTION: Message BIP7025W is logged if a         *
  *                      client attempts to subscribe to a       *
  *                      topic for which they are not            *
  *                      authorised. If authorisation is then    *
  *                      added, and the subscription request     *
  *                      re-attempted, a nullpointer exception   *
  *                      occurs and the Execution Group          *
  *                      terminates with messages BIP7053S and   *
  *                      BIP2121E.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a client attempts to subscribe to a topic for which they
  are not authorised to access, the message BIP7025W  "User does
  not have permission to subscribe to a topic" is logged. If
  authorisation is then added and the  subscription request is
  made again, the Execution Group terminates after a null
  pointer exception. Messages  BIP7053S and BIP2121E are logged.
  
  The problem occurs because the first failed attempt to
  register the subscription creates a Client User record for
  the subscription even though the subscription was
  unsuccessful. When the subsequent subscription attempt is
  made, the broker finds the Client User record and assumes
  there must exist a subscription record for that client and
  attempts to access it. Because it doesn't exist a nullpointer
  exception is generated.
  

Problem conclusion

• A change has been made to only add the Client User record if
  at least one topic subscription request has been successful.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WMB SOL SPARC

• Fixed component ID

  5724J0502

Applicable component levels

• R100 PSY

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