PH38031: MQ 9.2 SECURITY ASSEMBLER STUB CSQ4BAX3 PASSES UNEXPECTED REASONCODE VALUE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Development describes that CSQ4BAX3 STORAGE OBTAINs stack
  storage, saving the input return code into a local stack
  variable prior to the BPX1PWD call being made.  It then passes
  the stack return and reason code variables to the BPX1PWD call.
  After the call, the values in the stack fields are stored back
  in the user-supplied return and reason codes.
  .
  The issue occurs if the call to BPX1PWD succeeds with a
  'Return_value' of 0. The documentation for BPX1PWD states that
  the 'Return_code' and 'Reason_code' fields are only populated
  if the call fails (Return_value == -1). This will result in the
  stack return and reason code variables not being set when the
  call succeeds. This is fine for the return code,
  since MQ has saved the input return code in the variable before
  the BPX1PWD call, and will return the input value of the
  user-supplied return code.
  .
  However, the same treatment is not applied to the stack reason
  code variable so that, if the BPX1PWD succeeds, then CSQ4BAX3
  will store an uninitialized value into the user-supplied reason
  code. This value is unpredictable and will propagate through
  multiple CSQ4BAX3 calls.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 2 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Sample program CSQ4BAX3 does not        *
  *                      handle the parameter reason code        *
  *                      correctly.                              *
  ****************************************************************
  Sample program CSQ4BAX3 is a wrapper for a BPX1PWD call to
  verify a user ID, password pair. If valid credentials are
  passed to CSQ4BAX3, then the input reason code will be
  overwritten with uninitialised storage. This may manifest as a
  residual reason code from previous CSQ4BAX3 calls.
  

Problem conclusion

• Sample program CSQ4BAX3 has been corrected to not alter the
  parameter reason code field if valid credentials are passed to
  it. This is the same behaviour as a BPX1PWD call.
  

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:

  UI77952

Modules/Macros

• CSQ4BAX3 CSQ4BCX3
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R200 PSY UI77952

     UP21/12/11 P F112

Fix is available

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