IT37089: Channel socket error detection logic can generate invalid internal protocol flow

APAR status

• Closed as program error.

Error description

• Enhancements to IBM MQ's channel socket error detection logic
  were added under APAR IT30074. An internal data transmission
  used as part of this enhancement used a combination of internal
  flags that are not valid according to MQ's internal protocol
  specification.
  
  This invalid flag set is disregarded by message channel agents
  running supported levels of MQ, but may be reported as invalid
  by third party applications which attempt to validate
  communications using MQ's specification.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This APAR might affect users of IBM MQ who have applied APAR
  IT30074 and who have non-IBM vendor products connecting directly
  (without using an IBM-supplied MQ client) to the queue manager
  using a licensed implementation of MQ's internal protocol (FAP).
  
  The possibility of encountering this issue will be dependent on
  the vendor's implementation of the protocol, and the level of
  checking performed on data transmissions.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The logic added by APAR IT30074 uses an internal status
  transmission to perform healthchecking of the network link. A
  logic error in the IT30074 change meant that control flags were
  set on this transmission that were not valid.
  
  The invalid control flags are meaningless in this scenario, and
  so are ignored by all IBM-supplied clients and queue managers,
  however some MQ-compatible products offered by thirdparty
  vendors may report the flags as invalid, which may result in
  further errors depending on the vendor's chosen handling of such
  errors.
  

Problem conclusion

• The logic added under IT30074 has been revised to avoid setting
  the invalid flags. Additionally, the IT30074 logic is not used
  for a protocol level of 4 or lower, which is a lower level than
  in use by any currently supported IBM-supplied queue manager or
  client.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.1 LTS   9.1.0.9
  v9.2 LTS   9.2.0.4
  v9.x CD    9.2.4
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels

• R910 PSY

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