PH24145: GET CONTAINER REQUEST CAUSES 0C4S AND STORAGE VIOLATIONS DUE TO INVALID FLENGTH. NO AEYF ABEND IS PRODUCED.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A GET CONTAINER command was issued from an application with an
  invalid FLENGTH parameter. This invalid FLENGTH caused overlays
  of lots of storage including pages of CICS control blocks and
  leading/trailing check zones for task storage areas.
  
  Page faults in MVS system trace show module DFHEIBAM accessing
  the overlaid pages. DFHEIBAM tries to detect bad pointers and
  lengths before moving any storage by 'touching' each page within
  the range of the INTO parameter + FLENGTH specified on the
  GET CONTAINER command. If an 0C4 occurs, CICS will convert the
  error into an abend AEYF for the task. However, this has not
  happened because each page touched by DFHEIBAM within the range
  of INTO+FLENGTH is both GETMAINed and accessible in CICS key.
  So even with Storage Protection turned on, no 0C4 or AEYF
  occurs, the GET CONTAINER request completes normally, and lots
  of storage is overlaid. CICS then issues storage violations
  (DFHSM0102 message) and program checks for various components.
  
  CICS should improve its checking to try and avoid overlays of
  storage when bad pointers/lengths are passed on a GET CONTAINER
  command.
  
  Additional Symptom(s) Search Keyword(s):
  0C4 S0C4 abend0C4 DFHAP0001 DFHSR0001 PUT CONTAINER
  unpredictible errors
  KIXREVxxx
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: An application using GET CONTAINER INTO *
  *                      with an invalid FLENGTH value causes a  *
  *                      large overlay of CICS storage with      *
  *                      unpredictable results.                  *
  ****************************************************************
  Access to the GET CONTAINER INTO area is checked by CICS prior
  to moving any data but this is done running in CICS key.
  Applications running in USER key should not be permitted to
  address CICS key storage as part of the GET CONTAINER INTO area.
  
  Applications may be overlaying CICS Key storage in this way, and
  yet errors may not be apparent. These applications should be
  abended AEYF.
  
  Keywords: DFHEIBAM ABENDAEYF
  

Problem conclusion

• DFHEIBAM will switch to run with the application's EXEC key
  before it checks to see if storage access is permitted.
  This will help to protect CICS storage when the application runs
  in user key with CICS storage protection active. Note that this
  APAR will not prevent GET CONTAINER INTO from invalidly moving
  data into CICS key storage unless the application runs in USER
  key.
  

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:

Modules/Macros

• DFHEIBAM
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI70400

     UP20/07/21 P F007

• R200 PSY UI70401

     UP20/07/09 P F007

• R300 PSY UI70402

     UP20/07/09 P F007

Fix is available

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