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

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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 number

    IV83471

  • Reported component name

    WMQ LIN X86 V7

  • Reported component ID

    5724H7224

  • Reported release

    710

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-04-06

  • Closed date

    2016-04-29

  • Last modified date

    2016-04-29

  • 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

       UP

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Document Information

Modified date:
08 March 2021