PI27764: EZBTCRD (UI16041 14.073)+018BE4 S0C4/00000 WHEN RUNNING AT-TLS

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• A timing window exists in AT-TLS which can cause data to be
  decrypted
  when processing inbound data and a SRB to be scheduled to
  decrypt the same data.  The SRB will not find any data to
  decrypt and will abend.  The timing window exists if data
  arrives in to be decrypted after AT-TLS already scheduled a SRB
  to decrypt data.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the IBM Communications Server   *
  *                 for z/OS Version 1 Release(s) 13 IP:         *
  *                 ATTLS                                        *
  ****************************************************************
  * PROBLEM DESCRIPTION: EZBTCRD abends processing an ATTLS      *
  *                      connection because there is no data     *
  *                      available to be decrypted.              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Encrypted data arrives while the SSL handshake is completing.
  A timing window exists where two threads can try to decrypt
  data.  This can cause the second thread to abend because
  there is no data available on the TLSX receive queue to
  decrypt.
  +-------------------------------------------------------------+
  + Please check our Communications Server for OS/390 homepages +
  + for common networking tips and fixes.  The URL for these    +
  + homepages can be found in Informational APAR II11334.       +
  +-------------------------------------------------------------+
  

Problem conclusion

Temporary fix

Comments

• ATTLS is updated to set a flag which will prevent decryption
  from scheduling decryption until the SSL handshake is
  complete.
  This APAR contains the fix for defect 21941.
  

APAR Information

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

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

  UI22548

Modules/Macros

•    EZBTLCWK EZBTLWRQ EZBZTLUT
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R1D0 PSY UI22548

     UP15/06/08 P F506

Fix is available

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