IV83471: UPDATING MQ CLIENT FROM MQ V7.1.0.6 TO MQ V7.1.0.7 CAUSES TLS/SSL ENCRYPTED CHANNELS TO FAIL.

APAR status

• Closed as program error.

Error description

• After applying v7.1.0.7 fixpack to existing v7.1.0.6 MQ
  clients, MQ applications which use TLS/SSL encrypted channels
  fail to connect, and start receiving:
  MQCONN ended with reason code 2393.
  
  The installation error log will show:
  
  AMQ9620: Internal error on call to SSL function on channel
  'CHANNEL' to host
  'localhost'.
  
  EXPLANATION:
  An error indicating a software problem was returned from a
  function which is
  used to provide SSL or TLS support. The error code returned was
  '702'. The
  function call was 'gsk_attribute_set_buff -
  GSK_V3_CIPHER_SPECS_EX -
  cciSslSetCipherSpecs'.
  

Local fix

• Enable deprecated TLS CipherSpecs within the SSL stanza of the
  qm.ini file as follows:
  
  SSL:
      AllowWeakCipherSpec=Yes
  
  
  
  Alternatively, these CipherSpecs may be re-enabled by setting or
  exporting the following environment variable to any value:
  
  AMQ_SSL_WEAK_CIPHER_ENABLE
  
  The variable should be set/exported within the environment used
  to start the queue manager. Defining this environment variable
  enables the CipherSpecs regardless of the value specified in the
  qm.ini file.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of WebSphere MQ 7.1.0.7 attempting to connect to a
  queue manager over a secure channel
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  APAR IV73287 removed a number of CipherSpecs from the default MQ
  configuration in order to resolve the security vulnerability
  popularly known as Bar-Mitzvah.
  
  Due to this change when an MQ client initialises the CipherSpecs
  it can use to communicate with the queue manager, an empty
  string is passed to the library which handles secure
  connections.
  
  Queue managers are also susceptible to this problem where SSLv3
  has been enabled (AllowSSLV3), but weak ciphers have not been
  enabled (AllowWeakCipherSpec). Unlike the MQ client, the MQ
  queue manager is not susceptible to this problem with the
  default configuration.
  
  The version of this library shipped in MQ 7.1 rejected the empty
  string as an invalid value. This error is not handled and the
  client fails the connection.
  

Problem conclusion

• The code was changed to ensure when initialising CipherSpecs an
  empty string is not passed to the library which handles secure
  connections.
  
  A preventative section of this code change is ported forward to
  MQ versions 7.5 and 8, however these versions are not affected
  by the loss of functionality described above.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v7.1       7.1.0.8
  v7.5       7.5.0.7
  v8.0       8.0.0.5
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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:

Fix information

• Fixed component name

  WMQ LIN X86 V7

• Fixed component ID

  5724H7224

Applicable component levels

• R710 PSY

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