PI39033: DUMP TITLE=CSQ2,ABN=0C4-00000011,C=R3600.710.CHIN,M=CSQXDISP, LOC=CSQXRCTL.CMQXREVN+01B66

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• The customer is running WebSphere MQ on z/OS V710 when running
  along, they received:
  DUMP TITLE=CSQ2,ABN=0C4-00000011,C=R3600.710.CHIN,M=CSQXDISP,
          LOC=CSQXRCTL.CMQXREVN+01B66
  .
  Event functions module CMQXREVN (v710 base) failing at offset
  x'01B66'
  .
  MSTR Log shows:
  .
  18.46.44 IEA794I SVC DUMP HAS CAPTURED:
           DUMPID=001 REQUESTED BY JOB (CSQ2CHIN)
           DUMP TITLE=CSQ2,ABN=
           0C4-00000011,C=R3600.710.CHIN,M=CSQXDISP,
           LOC=CSQXRCTL.CMQXREVN+01B66
  .
  CHIN log shows:
  .
  18.46.44 +CSQX112E +CSQ2 CSQXDISP Dispatcher process error,
         TCB=009BC6D8 reason=0C4000-00000011
  .
  Looking through the Savearea chain, it appears that an event was
  trying to be written to the SYSTEM.ADMIN.CHANNEL.EVENT queue for
  a CLUSRCVR channel.
  .
  The change team reviewed the dump and found that the abend
  occurs when CHLAUTH processing attempts to put a warning
  event message to SYSTEM.ADMIN.CHANNEL.EVENT due to a channel
  using SSL matching a CHLAUTH rule that would block it with the
  WARN(YES) option.
  .
  Looking at the configured CHLAUTH rules I can see that the
  CLUSRCVR channel has a rule to warn on any unexpected
  connections from queue managers for which no other rule matches.
  In this case the remote queue manager, there is no rule to allow
  connections from this queue manager.
  .
  While putting the warning event message to the event queue,
  rsiEvent is called and is passed various attributes of the
  channel. In the failing case, it has been passed a pointer to
  the SSLPeerName, and is attempting to determine the length of
  this distinguished name. However, rsiEvent incorrectly assumes
  the storage containing this value is 1024 bytes long, however in
  this case it is just long enough to contain the actual value.
  While attempting to determine the correct length, GetLen
  attempts to access inaccessible storage beyond the end of the
  storage allocated for the SSLPeerName value and abends 0C4.
  

Local fix

• This abend can be avoided by adding an appropriate CHLAUTH rule
  to allow connections from queue manager on these channels
  (assuming that this queue manager is expected to be connecting
  using these channels).
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 1 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: MQRC_CHANNEL_BLOCKED_WARNING event      *
  *                      messages contain invalid data in the    *
  *                      MQCACH_SSL_PEER_NAME parameter.         *
  *                      In some cases abend 0C4 in              *
  *                      CSQXRCTL.CMQXREVN occurs during         *
  *                      generation of the message.              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  During start up of a channel using SSL/TLS, rriCheckChlAuth is
  called to evaluate any matching CHLAUTH rules for the channel.
  If a rule with WARN(YES) is matched, rsiEvent is called to
  generate an event message with reason
  MQRC_CHANNEL_BLOCKED_WARNING, and reason qualifier
  (MQIACF_REASON_QUALIFIER) MQRQ_CHANNEL_BLOCKED_NOACCESS.
  During generation of the event message, for SSL/TLS channels
  the MQCACH_SSL_PEER_NAME parameter is added to the event
  message, however an error in calculating the length of the SSL
  Peer Name can result in either:
   - additional unexpected data being added to the SSL peer name
   in the event message
  or
   - abend 0C4 being issued
  

Problem conclusion

Temporary fix

Comments

• The correct SSLPeerName length is passed to rsiEvent, preventing
  rsiEvent from calculating the length incorrectly.
  

APAR Information

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

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

  UI27092

Modules/Macros

• CMQXREVN CMQXRMSA CSQXCCCX CSQXRMRS
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UI27092

     UP15/06/03 P F506

Fix is available

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