IBM Support

IT27021: .NET client application connecting with elliptical curve cipherSuite fails with MQRC_Q_MGR_NOT_AVAILABLE

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APAR status

  • Closed as program error.

Error description

  • When an MQ client application specifies a long name for an
    elliptic curve (ECC) CipherSpec, such as:
      TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P384
    
    This value is truncated to one that does not exist, such as:
      TLS_ECDHE_ECDSA_WITH_AES_256_GCM
    
    Client application reports MQRC_Q_MGR_NOT_AVAILABLE
    18:14:50.603251  :   {
    MQEncryptedSocket.MakeSecuredConnection()
    18:14:50.606793  :   Starting SSL Authentication
    18:14:50.777172  :   Exception received
    IBM.WMQ.Nmqi.NmqiException
    Message: MQRC_Q_MGR_NOT_AVAILABLE
    
    QM error log reports AMQ9631 error
    
    18:14:50.794140  1033203.1193412      :            RetCode =
    20009631,
    rc1 = 0, rc2 = 0, Comment1 = 'MQ.QUEUE    ', Comment2 =
    'ECDHE_ECDSA_AES_256_GCM_SHA384  ', Comment3=
    'TLS_RSA_WITH_AES_128_CBC_SHA
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of MQ .NET applications in managed mode connecting with an
    SSL Channel and using a CipherSpec with a name longer than 32
    characters.
    
    
    Platforms affected:
    Windows
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    Due to a coding error, a 32-character buffer was used internally
    within the MQ.NET code to record the CipherSpec to use. This
    meant that CipherSpecs with longer names were truncated.
    
    In the provided example, the MQ managed .NET client code was
    truncating the elliptic curve CipherSpec, which caused the .NET
    client to propose the default protocol level of either SSL3.0 or
    TLS 1.0 to the server during the handshake. The server was
    configured to reject this proposal.
    

Problem conclusion

  • The MQ managed .NET client code has been corrected such that it
    is able to internally use elliptic curve CipherSpec definitions
    which are greater than 32 characters long, so that correct
    SSL/TLS protocol version will be proposed to the server by the
    client.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.7
    v9.1 CD    9.1.3
    v9.1 LTS   9.1.0.3
    
    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

    IT27021

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-11-19

  • Closed date

    2019-04-26

  • Last modified date

    2019-04-26

  • 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

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
26 April 2019