PH54894: EXPOSE OCSP CACHING IN IHS

APAR status

• Closed as program error.

Error description

• IHS can be enabled to perform OCSP checking of client
  certificates, but there is no way to enable a cache.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM HTTP Server                *
  ****************************************************************
  * PROBLEM DESCRIPTION: When OCSP is configured in IHS, each    *
  *                      SSL                                     *
  *                      handshake with client authentication    *
  *                      results in contacting the OCSP server.  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When OCSP is configured in IHS, each SSL handshake with client
  authentication results in contacting the OCSP server.
  Note: On zOS, the System SSL OCSP cache defaults to enabled
  with
  256 entries.
  

Problem conclusion

• 1)
  
  The directive "SSLOCSPCacheSize" was added to allow Linux/AIX/Wi
  users to configure an in-memory LRU OCSP response cache (and all
  to configure the cache size).
  
  The cache lifetime is dictated by the OCSP response (nextUpdate
  or HTTP cache headers).
  
  2)
  
  On Linux/AIX/Windows, basic cache statistics can be viewed for t
  current process and virtualhost via /server-status.
  
  
  Example
  read_hit: 0, read_miss: 1, write_hit: 0, write_miss: 0, new:
  0, promoted_hit: 0, promoted_event: 0, resume ratio: 0, hit rati
  cache hit ratio:
  
  Meaning:
  - read_hit: the number of times a valid current OCSP response
  in the cache and so no actual OCSP request was required.
  - read_miss: the number of times a valid current OCSP response
  found in the cache and so an actual OCSP request was required.
  - write_hit: the number of times a response was renewed in the
  this should match read_hit unless the response was found in the
  but could not be used for other reasons.
  - write_miss: the number of times a new response was added to
  cache.
  - new: the number of new OCSP requests requested
    this is write_miss - read_miss.
  - lost: the number of times an otherwise still valid cache
  entries lost due to lack of space.
  - promoted_hit: the number of times a promoted item was found
  in the cache.
  - promoted_event: the number of ocsp responses that were
    promoted
  - resume ratio: the ratio of renewed to all cache writes, the
  the better.
  - hit ratio: ratio of renewed cache hits that were used. Note:
  responses that have expired will not be used which can lower thi
  ratio.
  - cache hit ratio: percentage ratio of OCSP responses used from
  the cache compared to the total including cached and those from
  new requests.
  
  The fix for this APAR is targeted for inclusion in IBM HTTP Serv
  packs 8.5.5.24 and 9.0.5.17. For more information, see 'Recommen
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

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

  IBM HTTP SERVER

• Fixed component ID

  5724J0801

Applicable component levels