PH38967: BUFFEROVERFLOWEXCEPTION CAUSES ACTIVATION SPECS TO STOP

APAR status

• Closed as program error.

Error description

• If an endpointName, in the very case it is a String of length
  187, is written to the JFapByteBuffer 1st, along with 2 bytes
  for the length - that allocates a single data buffer of min size
  200 (it would allocate more if the requested length was > 200)
  so we have a 200 byte buffer with 189 bytes of data in it.  Next
  the WMQRAJFAPCommunicator writes the id, an int (ie 4 bytes),
  the JFapByteBuffer sees it has a data buffer with 11 bytes free
  so writes the bytes in that data buffer - there are now 193
  bytes used and 7 free.  Next it writes the craEpoch, a long
  which is of course 8 bytes - here the JFapByteBuffer.putLong
  should check it has 8 bytes left, see it only has 7 and allocate
  an extra 200 byte data buffer - but it only checks it has 4
  bytes left (the bug) so tries to write the 8 byte long into the
  7 remaining bytes - and that's why the BufferOverflowException
  occurs.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server V9.0                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION: BufferOverflowException can be thrown   *
  *                      in an ActivationSpec, causing the       *
  *                      ActivationSpec to stop.                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The putter methods for adding data to a JFapByteBuffer check
  whether there is enough space for the new data to be added,
  and extend the buffer if required. These checks used hard-coded
  values for the length of each data type.
  An error meant that, when a long was being added, the buffer
  was only checked for 4 bytes of space instead of
  8. Consequently, when long data is being added to an almost
  full buffer, the check might incorrectly determine that there
  is enough space to add the data, resulting in
  a BufferOverflowException being thrown when the
  data is written.
  A trace is likely to show a call to JFapByteBuffer.putLong()
  just before the Exception is thrown.
  

Problem conclusion

• The fix for this APAR is targeted for inclusion in fix pack
  9.0.5.11 and 8.5.5.21. For more information, see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

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

  WEBSPHERE FOR Z

• Fixed component ID

  5655I3500

Applicable component levels