PH71430: ABN= 5C6-00E7080D IN CSQXBP64

APAR status

• Closed as program error.

Error description

• Examining the state from the process which abended shows that i
  was due to an invalid storage request length in CSQXBP64. This
  is a similar symptom to the problem seen in APAR PH68925, but
  the origin of the invalid length is different.
  
  APAR PH68925 validates the CallLength field in a TSH flow, but
  in this instance the invalid data is part of a
  rfpTST_REQUEST_MSGS flow and the invalid field comes from the
  MaxMsgLength field. This can be seen in the last flow on the
  channel instance before the abend.
  
  The MaxMsgLength fields is at offset x34, but all of the data
  from x30 to x40 looks invalid. The source of the invalid data is
  likely on the client side.
  
  This APAR will aim to add validation of the MaxMsgLength field
  from rfpTST_REQUEST_MSGS flows to reject the request without an
  abend and without creating the DISABLED status entry.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 4 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend 5C6-00E7080D occurs in CSQXBP64   *
  *                      when processing an rfpTST_REQUEST_MSGS  *
  *                      flow to get messages using a SVRCONN    *
  *                      channel with SHARECNV>0.                *
  *                      Following recovery for the abend the    *
  *                      SVRCONN channel remains disabled.       *
  ****************************************************************
  While getting messages using a SVRCONN channel, an invalid
  rfpTST_REQUEST_MSGS flow was received. Depending on the state of
  the consumer when the flow is received, this can lead to an
  attempt to allocate an invalidly sized buffer, resulting in the
  reported abend.
  During recovery for the abend, the channel is set to disabled
  state and must be manually restarted.
  

Problem conclusion

• Additional validation of the flow is added to detect the invalid
  values earlier. When detected, an FFST is captured and an error
  is returned to the application, preventing the reported abend.
  In addition, recovery for SVRCONN channels has been changed to
  avoid setting the channel to the disabled state in this
  situation.
  

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:

  UO08277

Modules/Macros

• CMQXRSTF CSQMXAL6 CSQXBP64 CSQXRCAP
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels