PH63295: FIX FOR ENDLESS LOOP IN CIPHER

APAR status

• Closed as program error.

Error description

• Error Message: If more than one thread has a reference to the
  same HybridCipher
  instance it's possible for the "theCipher" field to be set to a
  non-null value just after it is set to null in
  getBestInstance().
  This can lead to an endless loop.
  .
  Stack Trace: Loop occurs like this:
  +258  aconstnull  <<< +240 <HAT>+312 <HAT>+505
  +259  aload0getfield
  +260  getfield 185
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.theCipher
  (Ljavax/crypto/Cipher;)
  +263  ifacmpne C>> +508
  +266  aconstnull
  +267  aload0getfield
  +268  getfield 141
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.theProvider
  (Ljava/lang/String;)
  +271  ifacmpeq C>> +508
  +274  getstatic 159
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.debug
  (Lcom/ibm/misc/Debug;)
  +277  ifnull C>> +295
  +280  getstatic 159
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.debug
  (Lcom/ibm/misc/Debug;)
  +283  ldc2lw 283 (long) 0x0000000000004000
  +286  ldc 1 (java.lang.String)
  "com.ibm.crypto.ibmjcehybrid.provider.HybridCipher"
  +288  ldc 111 (java.lang.String) "getBestInstance"
  +290  ldc 117 (java.lang.String) "Top of loop 2"
  +292  invokevirtual 174
  {com/ibm/misc/Debug.text(JLjava/lang/Object;Ljava/lang/String;Lj
  
  ava/lang/String;)V}
  +295  aload0  <<< +277
  +296  aload0getfield
  +297  getfield 140
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.cipherSpec
  (Ljava/lang/String;)
  +300  aload0getfield
  +301  getfield 141
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.theProvider
  (Ljava/lang/String;)
  +304  invokestatic 248
  {javax/crypto/Cipher.getInstance(Ljava/lang/String;Ljava/lang/St
  
  ring;)Ljavax/crypto/Cipher;}
  +307  putfield 185
  com/ibm/crypto/ibmjcehybrid/provider/HybridCipher.theCipher
  (Ljavax/crypto/Cipher;)
  +310  iconst0
  +311  istore3
  +312  goto U>> <HAT>+258      <----- Loop 2 back edge
  

Local fix

• Run it again
  

Problem summary

• If more than one thread has a reference to the same HybridCipher
  instance it's possible for the "theCipher" field to be set to a
  non-null value just after it is set to null in
  getBestInstance().
  This can lead to an endless loop.
  

Problem conclusion

• A change has been made where:
  After peeling apart the Java core we can see that notDone ==
  True at the same time theCipher != null. Which should not be
  possible becuase they are set at the same time in this loop.
  Nested while loops will use a variable that is internal only to
  the class called(notDone)
  To avoid possibility of thread manipulating previous external
  variable (theCipher)
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
  IBM SDK, Java Technology Edition
     8    SR8 FP35  (8.0.8.35)
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For the z/OS operating system:
    - Java SDK Products on z/OS
      https://www.ibm.com/support/pages/java-sdk-products-zos
  

Temporary fix

• Run it again
  

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