PI14176: TELNET ABEND0C4 EZBTTSRV CALLER EZBTTCFB FREEMSGTRIPLE AICOB SKMB ALREADY FREED

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Telnet ABEND0C4 in EZBTTSRV, caller EZBTTCFB, when trying to
  free CVB_SSL_DATA_ORIG pointed to by register 10 which is zero.
  The problem occurs when two threads manipulate the AIOCB
  message triple and the CVB pointers simultaneously.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of the IBM Communications Server                   *
  * for z/OS Version 2 Release 1 IP: Telnet                      *
  * Server Express Logon                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Telnet attempts to free storage with a 0 pointer when        *
  * multiple Express Logon messages are received in the same     *
  * read request.                                                *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply PTF.                                                   *
  ****************************************************************
  The problem may be summarized as follows:
  1) Telnet receives multiple SSL records in one receive buffer.
  2) Telnet processes the first SSL record and queues a request to
  obtain a userid from the certificate.
  3) Telnet processes the second SSL record and issues a TCP
  receive request
  4) Telnet processes the queued request and issues a second TCP
  receive on the same socket.
  5) Multiple SSL record arrive, driving both receives.  Telnet
  attempts to free storage already cleared by the other receive
  thread.
  

Problem conclusion

• EZBTTRCV is updated to maintain the flag to not issue a TCP
  receive request over multiple SSL records.
  
  EZBTTTSK is updated to check the CVB for the flag to skip
  issuing a TCP receive.
  

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:

  UI17208

Modules/Macros

• EZBTTRCV EZBTTTSK
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R210 PSY UI17208

     UP14/06/06 P F406

Fix is available

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