PI18968: DFHSO0001 ABEND CODE 0C4/AKEX OCCURRED AT OFFSET X'04B2' IN MODULE DFHSOS22

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• You are running CICS TS 5.1 and receive the following error:
  
  DFHSO0001 abend (code 0C4/AKEX) has occurred at offset 04B2
            in module DFHSOS22
  
  The failing instruction is an OI instruction:  9610 2014.
  The abend is occurring due to Reg2 being zeros.  Reg2 should be
  the address of the SOCKET_SSL_DATA.  Reg2 was loaded from the
  Socket object but this has been freed by CIST.
  
  CISR is processing a receive request instead of a send.  SSL is
  being used.
  
  
  
  Additional Symptom(s) Search Keyword(s): KIXREVDAM
  0C4 DFHSOSO22 SECURE_SOC_READ CONNECTION_CLOSED
  ABEND0C4 ABENDS0C4
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: MSGDFHSO0001 ABEND0C4 in DFHSOS22       *
  *                      in routine soso_async_receive.          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  DFHSO0001 abend (code 0C4/AKEX) has occurred in routine
  soso_async_receive in DFHSOS22 when an SSL IPCONN is closed.
  The CICS system has been started with ENCRYPTION=ALL which
  supports TLS 1.0, TLS 1.1 and TLS 1.2.
  The SSL connection established for the IPCONN uses TLS 1.2.
  The IPCONN is closed by the remote partner. A Drain command
  is sent by the partner which triggers the attach of a CIST task
  on CICS to terminate the IPCONN.
  The partner then closes the socket connection for the IPCONN.
  As this is a SSL socket, an SSL alert is sent down the socket
  before it is closed.
  The arrival of data on the socket is detected by the sockets
  listener task. A routine called CHECK_FOR_SSL_ALERT is called
  to detect if a socket closure alert has been sent.
  CHECK_FOR_SSL_ALERT has code to detect a TLS 1.0 alert but it
  has no code to detect a TLS 1.1 or TLS 1.2 alert.
  This results in the data being treated as a normal data flow
  instead of a socket closure.
  The consequence of this is that the IPIC receiver task CISR is
  posted to receive the socket data. This results in a race to
  receive data (by CISR) and close the socket (by CIST).
  CISR program checks in DFHSOS22 which has been called for
  an ASYNC receive. The program check occurs when CISR tries to
  set the gsk_closed flag in the socket SSL extension.
  By this time the socket has been closed and deleted by the
  CIST task.
  

Problem conclusion

• Socket routine CHECK_FOR_SSL_ALERT has been updated to detect
  TLS 1.1 and TLS 1.2 alerts.
  DFHSOS22 and DFHSOS07 have been updated to confirm that a socket
  object sill exists before updating the gsk_closed flag.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

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

  UI20761 UI20762

Modules/Macros

• DFHSOS07 DFHSOS22
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R800 PSY UI20761

     UP14/08/30 P F408

• R900 PSY UI20762

     UP14/08/30 P F408

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.