IBM Support

IT17824: A CLIENT APPLICATION FAILS TO CONNECT TO A QUEUE MANAGER WITH ERROR AMQ9777(CHANNEL WAS BLOCKED) WHEN CLIENT SIDE EXIT IS USED

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APAR status

  • Closed as program error.

Error description

  • A client application fails to connect to a queue manager with
    error AMQ9777: Channel was blocked.
    
    AMQ9777: Channel was blocked
    The inbound channel 'A.TO.B' was blocked from address 'abc
    (xxx.xxx.xxx.xxx)' because the active values of the channel
    matched a record configured with USERSRC(NOACCESS). The active
    values of the channel were 'CLNTUSER('.
    
    This error is reported when there is a usermap rule which maps
    CLNTUSER 'XYZ' to 'ABC' and when there is a addressmap rule that
    blocks all the address. Along with the above CHLAUTH rule,  when
    CONNAUTH and a client-side exit are used, MQ is unable to honor
    USERMAP rule. The CLNTUSER in this case is a MQCSP user.
    
    Along with the above CHLAUTH rule, when CONNAUTH and a
    client-side exit are used, MQ is unable to honor USERMAP rule.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users who use a client-side exit along with CHLAUTH and CONNAUTH
    rules.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When an exit is used in the client side (e.g: mqccred exit)
    along with CHLAUTH and CONNAUTH rules, IBM MQ was unable to
    assert the client user and hence was failing to honour a USERMAP
    rule.
    
    This resulted in valid user credentials being incorrectly
    rejected by the queue manager.
    

Problem conclusion

  • IBM MQ code has been updated such that it is able to assert the
    right user so that it could honour the USERMAP rule.
    
    Fix for APAR IT12825 has to be included along with this.
    
    To have the queue manager use this new behaviour, set the
    ChlauthEarlyAdopt attribute under the Channels stanza to 'e' or
    'E',
    e.g.
    
    Channels:
       ChlauthEarlyAdopt=e
    
    Note that setting ChlauthEarlyAdopt to 'e' or 'E' when security
    exits are not in use will have the same effect as setting it to
    'y' or 'Y'.
    
    APAR IT18052 made further changes to the new ChlauthEarlyAdopt
    parameter and so it is recommended that users review the details
    of that APAR in combination with this one.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.7
    
    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

    IT17824

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-11-07

  • Closed date

    2017-04-11

  • Last modified date

    2017-07-26

  • 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 BASE MULTIP

  • Fixed component ID

    5724H7251

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
26 July 2017