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