PI43898: DFHSO0001 ABEND (CODE 0C4/AKEX) OFFSET X'04B8' IN DFHSOS07 HTTP REQUEST HAS ACCEPT-CHARSET LIST GREATER THAN 4K

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• You are running CICS Transaction Server 5.1 and receive
  the following errors:
  DFHSO0001 An abend (code 0C4/AKEX) has occurred at
            offset X'04B8' in module DFHSOS07.
  DFHSO0002 A severe error (code X'029F')as occurred
            in module DFHSOCK.
  The application is receiving a  web request when the program
  check occurs.  The failing instruction is  MVCL R14,R0 due to
  R14 being close to a MEG boundary, that is in key 0.
  The code is attempting to move the request into
  a work buffer.
  Here are the last modules in the stack for the task:
  Module
  DFHWBCL
  READ_RESPONSE
  READ_BLOCK_RAW
  DFHSOCK
  RECEIVE_SOCK
  TCPIP_RECEIVE
  DFHSOS07
  .
  The problem is due to the fact that the client has
  sent in a request with a very large
  Accept-Charset list - over 4K in length.
  DFHWBCL handles this situation as an exception and should
  return wbcl_exception/wbcl_http_error.  However, after the
  peek has been abandoned a real receive gets issued anyway.
  This always for the peeked header length plus 2 (for the
  final CRLF which had not been included in the length so far).
  This is what causes the length to be 2 bytes more than will
  fit into the buffer-causing the program check .
  Additional Symptom(s) Search Keyword(s): KIXREVEPH
  
  DFHTS0001 An abend (code 0C4/AKEA) has occurred at
  offset X'3EBA' in module DFHTSRM.
  DFHRM0002 A severe error (code X'020B') has occurred in
  module DFHRMUO.
  The abend0c4 in DFHTSRM occurs during COMMIT processing
  in routine TSRM_DELETE_QAB.
  This problem is caused by the fact that DFHWBCL does not
  handle HTTP responses with more than 4K of headers.
  When it gets to the end of its 4K work buffer without
  finding the double CRLF a real sockets receive
  is issued for the remaining buffer length plus two.
  The assumption is that the earlier peeking of the
  header found the last CRLF but points past it so the length
  needs to be two larger leading to the overlay.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Message DFHSO0001 Abend (CODE 0C4/AKEX) *
  *                      offset x'04B8' in DFHSOS07 is issued    *
  *                      when HTTP response header has           *
  *                      ACCEPT-CHARSET list greater than 4k.    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  CICS web client sends WEB CONVERSE command to server and gets
  an HTTP response with header length larger than 4k. DFHWBCL is
  invoked to peek the header first before actual read to make
  sure that all the HTTP headers have been received.
  The buffer used to peek the header has a size of 4k. So the
  peek of 4k header complete before the end of header has been
  found(a double CRLF).
  Exception is set with reason HTTP_ERROR due to syntax error.
  The code does not immediately return and instead it continues
  to perform an actual read for the socket data with length
  4k + 2 to include double CRLF.
  Then it causes 0C4 since the extra 2 bytes address are in
  unaddressable storage.
  
  Additional Keywords: abend0C4 S0C4 abendS0C4 abendAKEX
  

Problem conclusion

• DFHWBCL has been changed to treat the response header length >
  4k as invalid and return exception with reason
  wbcl_header_too_long.
  
  The CICS Transaction Server for z/OS Version 5 Release 1
  Application Programming Reference, SC34-2845-02, will be updated
  for the commands 'WEB CONVERSE' and 'WEB RECEIVE (client)' to
  add a new RESP2 value of 157 to the list of values for the
  '16 INVREQ' condition as follows:
      157  The http headers in the response are longer than 4k and
           CICS is unable to process this http response.
           The session is unusable and a WEB CLOSE command is
           required.
  
  The CICS Transaction Server for z/OS Version 5 Release 2
  Application Programming Reference, SC34-7267-00, will be updated
  with the same changes.
  

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:

  UI31193 UI31194 UI31195 UI31196

Modules/Macros

• DFHEIWB  DFHISCO  DFHISEM  DFHISPH  DFHISRR  DFHISSR  DFHPIAD
  DFHPIAT  DFHPIA1  DFHPITH  DFHPITS  DFHSJJS  DFHWBCL  DFHWBCLI
  DFHWBCLT DFHWBDUF DFHWBSV  DFHWBXM  DFJ@H360
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R80D PSY UI31194

     UP15/09/24 P F509

• R800 PSY UI31193

     UP15/09/24 P F509

• R90D PSY UI31196

     UP15/09/24 P F509

• R900 PSY UI31195

     UP15/09/24 P F509

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.