IT14555: PCOM: 3270 SESSION HANG USING MSCAPI AFTER UPGRADE TO 6.0.16 REFRESH LEVEL

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PCOMM_60170_JAP_RefreshPack
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PCOMM_60170_KOR_RefreshPack
PCOMM_60170_CHT_RefreshPack
PCOMM_60170_CHS_RefreshPack
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IBM Personal Communications 12.0.0.1
Personal Communications 6.0.17

APAR status

• Closed as program error.

Error description

• 3270 TLS1.1 or TLS1.2 session hang using MSCAPI after upgrade
  to PCOM 6.0.16 German.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * IBM Personal Communications 3270 secure sessions configured  *
  * with MSCAPI cryptography service.                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Secure 3270 sessions, configured with MSCAPI cryptography    *
  * service, may be found unresponsive (hung). Problem has been  *
  * reported at IBM Personal Communications refreshpack 6.0.16.  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  APAR SE37679 changed PCSTLNET.DLL module, where the
  ReceiveBufferSize was set to 16K bytes for secured connections.
  This caused some 3270 sessions to crash due to a known buffer
  overflow issue, as documented in the technote:
  
  http://www.ibm.com/support/docview.wss?uid=swg21647537
  
  One of the solutions suggested in the technote, to alter the
  buffer size, did not take effect as the buffer size was set to a
  fixed value. APAR IT10406 was used to address this, where the
  3270 sessions were excluded from SE37679 changes.
  
  These changes however make 3270 secure sessions vulnerable to
  crashing under the scenarios addressed by SE37679.
  

Problem conclusion

• To address the problem, PCSTLNET.DLL changes have been made to
  set the value of ReceiveBufferSize keyword as follows:
  
  (a)  If it is set by the user (not left to default value), the
  set value will be honored and used for both secure and
  non-secure sessions.
  (b) If the keyword is not set, a default value of 16K will be
  set as the default value for secure sessions; whereas, a default
  value of 8K will be set as the default value for non-secure
  sessions.
  
  Users are advised to use the product default values. The
  technote -
  http://www.ibm.com/support/docview.wss?uid=swg21647537
  - is suggested only when the reported symptoms are observed.
  
  Fix scheduled for IBM Personal Communications 6.0.17 Refresh
  Pack and 12.0.0.1 Fix Pack.
  

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

  PCOMM COMBO-ENC

• Fixed component ID

  5639I7000

Applicable component levels

• R60G PSY

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