PI28560: ADD HTTPDISPATCHER PROPERTY TO CONTROL PADDING OF A 404 MESSAGE.

8.5.5.5: WebSphere Application Server V8.5.5 Fix Pack 5
8.5.5.6: WebSphere Application Server V8.5.5 Fix Pack 6
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• When a request is received for an application context which
  does not exist, by default a message is returned which is
  padded to comprise 512 bytes. The additional padding added
  to the message can be used to determine that the request was
  processed by WebSphere Application Server Liberty profile.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server Liberty Profile                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: 404 message padding enables server      *
  *                      implementation to be identified.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  APAR PM86342 fixed an issue where the 404 message returned for a
  request for a non-existent resource was not displayed in all
  browsers. The problem was due to the message being less than 512
  bytes and PM86342 fixed this by adding padding to messages of
  less than 512 bytes in length. The padding added is a comment so
  it is not displayed by the browser, however it can be used to
  identify the server implementation to which the request was
  sent.
  

Problem conclusion

• The additional padding has been removed from the message and a
  httpDispatcher property added which must be set to true for the
  padding to be added. For example, in the server.xml:
  
  <httpDispatcher padAppOrContextRootMissingMessage="true">
  
  The default value is false. Note that some internet browsers
  will not display a message which is less than 512 bytes.
  
  The fix for this APAR is currently targeted for inclusion in fix
  pack 8.5.5.5.  Please refer to the Recommended Updates page for
  delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

• There are 2 possible workarounds:
  1. The problem only happens when the httpDispatcher property
  "enableWelcomePage" is set to false (default is true).
  2. Another httpDispatcher property
  "appOrContextRootMissingMessage" can be used to set the message
  returned when enableWelcomePage is set to false. If this is set
  to a message of at least 512 bytes no padding will be added.
  

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

  LIBERTY PROFILE

• Fixed component ID

  5724J0814

Applicable component levels

• R850 PSY

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