PK34180: FIX INCORRECT 304 RESPONSES FOR EXPIRED CACHE OBJECTS

PK53584; 2.0.47.1: IBM HTTP Server 2.0.47 Cumulative Interim Fix
PK65782; 2.0.47.1: IBM HTTP Server V2.0.47 Cumulative Interim Fix

APAR status

• Closed as program error.

Error description

• The customer used mod_cache/mod_mem_cache to cache proxied
  requests and reported broken images seen from multiple clients.
  The cause of the broken images was invalid 304 responses for
  non-conditional requests.  The problem starts occurring after
  the cache revalidation timeout has elasped.
  

Local fix

Problem summary

• An object was requested from the cache.  The cache
  revalidation timeout had expired, so mod_cache issued a
  conditional request internally to revalidate.  When the
  cached object was still valid, a 304 would be returned from
  the conditional response.  Because the 304 (not modified)
  was the response from the internally generated request, it
  could not necessarily be returned to the client (e.g., when
  the client issued an unconditional request).  But mod_cache
  neglected to reset the response to success, allowing the 304
  to be returned to the client.
  

Problem conclusion

• When mod_cache receives 304 for the request used to revalidate
  the cache object, it resets it to success for subsequent
  processing of the client request.
  This fix will be delivered in
  6.1.0.4 (z/OS)
  6.1.0.5 (distributed platforms)
  6.0.2.19
  Cumulative e-fix PK53584 for 2.0.47.1
  

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:

Modules/Macros

• MODCACHE
  

Fix information

• Fixed component name

  IBM HTTP SERVER

• Fixed component ID

  5724J0801

Applicable component levels

• R60A PSN

     UP

• R60H PSN

     UP

• R60P PSN

     UP

• R60I PSN

     UP

• R60S PSN

     UP

• R60W PSN

     UP

• R60Z PSN

     UP

• R61A PSN

     UP

• R61H PSN

     UP

• R61P PSN

     UP

• R61I PSN

     UP

• R61S PSN

     UP

• R61W PSN

     UP

• R61Z PSN

     UP