PI93233: CIPHER.DOFINAL() FAILS WHEN USING AES/GCM/NOPADDING WITH AAD DATA OF 13 BYTES AND A BLOCK SIZE OF 4081 TO 4096.

APAR status

• Closed as program error.

Error description

• Error Message: javax.crypto.ShortBufferException: Output buffer
  too short for GCM mode encryption because it must accommodate
  padding characters and the Authentication Tag. 4096 bytes given,
  4097 bytes needed.
  or
  javax.crypto.ShortBufferException: Output buffer too small
  .
  Stack Trace: IBMJCEHybridException: Failover exhausted, all
  registered providers
  attempted and failed.
  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, 4098 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:3053)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3053)
          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)
          at com.ibm.jsse2.n.a(n.java:358)
          at com.ibm.jsse2.e.a(e.java:30)
          at com.ibm.jsse2.e.a(e.java:55)
          at com.ibm.jsse2.t.a(t.java:42)
          at com.ibm.jsse2.aq.a(aq.java:488)
          at com.ibm.jsse2.aq.c(aq.java:185)
          at com.ibm.jsse2.aq.wrap(aq.java:101)
          at javax.net.ssl.SSLEngine.wrap(SSLEngine.java:33)
          at
  com.ibm.ws.channel.ssl.internal.SSLWriteServiceContext.encryptMe
  ssage(SSLWriteServiceContext.java:640)
  ...
          at java.lang.Thread.run(Thread.java:795)
  Exception#1 javax.crypto.ShortBufferException: Output buffer too
  small
  Stack Trace:
          at com.ibm.crypto.provider.aA.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:3053)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3053)
          at
  com.ibm.crypto.ibmjcehybrid.provider.HybridCipher.doFinal(Hybrid
  Cipher.java:3053)
          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)
  .... (more details in messages.log file attached, reached RTC
  description limit)
  .
  

Local fix

• Please add "GCM" to the
    jdk.tls.disabledAlgorithms
  property in the
    <java home>/lib/security/java.security
  file please.
  
  Please Note that z/OSMF override the java.security file with
    jvm.security.override.properties
  in directory
    /usr/lpp/zosmf/defaults/servers/zosmfServer
  Other products may do something similar.
  In this case the workaround will need to be applied to the
  override.
  
  Applying the workaround should result in the following or
  similar (depending on any additional user changes) String:
  (Note that the following 2 lines is a single line)
  jdk.tls.disabledAlgorithms=SSLv3, RC4, MD5withRSA, DH keySize <
  768, 3DES_EDE_CBC, DESede, EC keySize < 224, GCM
  
  This will remove the GCM Cipher Suite.
  The encryption, as a result of this change, will be only
  marginally
  weakened but still sufficiently strong.
  
  An alternative workround is to disable the GCM Cipher in the
  browser.
  

Problem summary

• The framework (ibmjcefw) attempts to reuse the IBMJCEHybrid
  Cipher object after the exception without reinitializing it,
  which fails.
  

Problem conclusion

• IBMJCEHybrid was modified so that when this exception was
  received it would reset the cipher object.
  
  For reference, the documentation
  https://docs.oracle.com/javase/8/docs/api/javax/crypto/Cipher.ht
  ml#doFinal(byte[], int, int, byte[]) does Note that this reset
  might be necessary.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP10  (8.0.5.10)
     7    SR10 FP20 (7.0.10.20)
     7 R1 SR4 FP20  (7.1.4.20)
  .
  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