PM93796: LINUX TCP API SELECT() CALL TO POLL() CALL CHANGES (RECENTLY MADE FOR THE FTP ADAPTER) NEED TO BE MADE TO SSL CODE AS WELL

APAR status

• Closed as program error.

Error description

• Limitations in the Redhat Linux TCP API mean that it is no
  longer best practice to use the select() call as this will have
  undefined behaviour when the descriptor count goes above 1024.
  
  The FTP adapter has been changed to use the poll() call instead.
  This APAR raised to show that a similar change is required for
  the shared SSL code.
  

Local fix

• WTXCQ - WTX00043214
  PB / PB
  Circumvention: None
  

Problem summary

• Users Affected:
  WebSphere Transformation Extender customers who use HTTP/S and
  FTP/S adapters on Linux platforms.
  
  Problem Description:
  The SSL library's use of the 'select' api function can lead to
  memory corruption, particularly when the number of open files
  descriptors and sockets exceed the 1024 limit.
  
  Platforms Affected:
  Linux, zLinux
  

Problem conclusion

• When running on Linux, the SSL portion of the FTP/S and HTTP/S
  adapters use the socket-based "poll" API function to query
  socket activity.  Before this fix, the "select" call was used,
  which introduced corruption if the socket descriptor exceeded
  the 1024 value.  Also, error condition logic was incorporated so
   that the POLLNVAL and POLLERR stops further activity on the
  socket.  The POLLERR will not stop activity if the next socket
  read/write operation will succeed.
  
  
  Delivered in:
  8.4.0.4, 8.4.1.1
  

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:

Fix information

• Fixed component name

  WTX FOR INT SER

• Fixed component ID

  5724M4010

Applicable component levels

• R840 PSY

     UP

• R841 PSY

     UP