PH01244: OUTPUT BUFFER TOO SHORT FOR GCM MODE ENCRYPTION USING IBMJCEHYBRID

APAR status

• Closed as program error.

Error description

• Error Message: The user experienced intermittent failures when
  they had IBMJCEHYBRID configured while using the AES/GCM mode
  of encryption. Customer failures were visible when a trace was
  taken using -Djavax.net.debug=true
  and -Djava.security.auth.debug=all. The failure was seen as a
  javax.crypto.ShortBufferException within the trace similar to
  what is listed
  below in the stack trace. The problem would also manifest itself
  occasionally with a "Bad record MAC" error being reported by
  JSSE.
  .
  Stack Trace: Exception#0 javax.crypto.ShortBufferException:
  Output buffer too short for GCM mode encryption because it must
  accommodate padding characters and the Authentication Tag. 4096
  bytes given, 4102 bytes needed.
  Stack Trace:
          at
  com.ibm.crypto.hdwrCCA.provider.AESCipher.engineDoFinal(AESCiphe
  r.java:1343)
          at javax.crypto.Cipher.doFinal(Unknown Source)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:2921)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3079)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3079)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.engineDoFinal(
  HybridCipher.java:2793)
          at javax.crypto.CipherSpi.a(Unknown Source)
          at javax.crypto.CipherSpi.engineDoFinal(Unknown Source)
          at javax.crypto.Cipher.doFinal(Unknown Source)
          ...
          ...
  Exception#1 javax.crypto.ShortBufferException: Output buffer too
  small
  Stack Trace:
          at com.ibm.crypto.provider.aH.a(Unknown Source)
          at
  com.ibm.crypto.provider.AESGCMCipher.engineDoFinal(Unknown
  Source)
          at javax.crypto.Cipher.doFinal(Unknown Source)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:2921)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3079)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3079)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3079)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.engineDoFinal(
  HybridCipher.java:2793)
          at javax.crypto.CipherSpi.a(Unknown Source)
          at javax.crypto.CipherSpi.engineDoFinal(Unknown Source)
          at javax.crypto.Cipher.doFinal(Unknown Source)
          ...
          ...
  .
  

Local fix

• Users can either remove the IBMJCEHYBRID provider from their
  environment or they can avoid use of the AES/GCM mode of
  encryption.
  

Problem summary

• The problem occurs when the JCE framework did not adjust the
  size of the buffer used for GCM crypto operations correctly.
  This resulted in a javax.crypto.ShortBufferException being
  thrown.
  

Problem conclusion

• A change has been made to the IBMJCEHYBRID provider in the IBM
  Java SDK such that the path that was executed in the JCE
  framework correctly accounted for the buffer size when executing
  GCM crypto operations.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP22  (8.0.5.22)
     7 R1 SR4 FP35  (7.1.4.35)
     7    SR10 FP35 (7.0.10.35)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

  JAVA Z/OS 64

• Fixed component ID

  620700104

Applicable component levels