PH39085: PROCESSING BASE64 ENCODED DATA USING JAXB CAN CAUSE A LOOP

APAR status

• Closed as program error.

Error description

• If a JAXB context is created manually (e.g. when processing a
  JMS message) and a Base64 string that contains more than 2
  filler characters is unmarked, an endless loop occurs in the
  XSBase64BinaryUtil class.
  
  Thread stack of looping thread:
  
  3XMTHREADINFO "WebContainer : 1" J9VMThread:0x0000000002BF5000,
  omrthread_t:0x00007FCD90003AE8,
  java/lang/Thread:0x00000000EF26AD88, state:R, prio=5
  3XMJAVALTHREAD (java/lang/Thread getId:0xFB, isDaemon:true)
  3XMTHREADINFO1 (native thread ID:0xFB0C, native priority:0x5,
  native policy:UNKNOWN, vmstate:CW, vm thread flags:0x00000081)
  3XMTHREADINFO2 (native stack address range
  from:0x00007FCFF40CB000, to:0x00007FCFF410B000, size:0x40000)
  3XMCPUTIME CPU usage total: 267.061820697 secs, current
  category="Application"
  3XMHEAPALLOC Heap bytes allocated since last GC cycle=0 (0x0)
  1INTERNAL Unable to obtain lock context information
  3XMTHREADINFO3 Java callstack:
  4XESTACKTRACE at com/ibm/xml/xlxp2/datatype/validation/XSBase64
  BinaryUtil.parseBase64BinaryUnbuffered(XSBase64BinaryUtil.java:
  181(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/datatype/validation/XSBase64
  BinaryUtil.parseBase64Binary(XSBase64BinaryUtil.java:75)
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/impl/Deserial
  izationContext.getBase64BinaryValue(DeserializationContext.java
  :1334)
  4XESTACKTRACE at foo/bar/Tes
  tType_JAXB_Deserialization_Stub.write(at.gv.brz.namespace.websp
  hereunmarshalling.TestType_JAXB_Deseria
  lization_Stub.java)
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/impl/Deserial
  izationContext.handleSimpleContent(DeserializationContext.java:
  762(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/impl/Deserial
  izationContext.handleEndElementEvent(DeserializationContext.jav
  a:412(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/impl/JAXBDocu
  mentScanner.produceEndElementEvent(JAXBDocumentScanner.java:234)
  4XESTACKTRACE at com/ibm/xml/xlxp2/scan/DocumentScanner.scanEnd
  Element(DocumentScanner.java:2583(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/scan/DocumentScanner.scanCon
  tent(DocumentScanner.java:1848(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/runtime/VMContext.scanConten
  t(VMContext.java:502(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/scan/DocumentScanner.nextEve
  nt(DocumentScanner.java:1283(CompiledCode))
  4XESTACKTRACE at com/ibm/xml/xlxp2/scan/DocumentScanner.parseDo
  cumentEntity(DocumentScanner.java:1175)
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/impl/JAXBDocu
  mentScanner.unmarshal(JAXBDocumentScanner.java:147)
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/UnmarshallerI
  mpl.unmarshal(UnmarshallerImpl.java:131)
  4XESTACKTRACE at com/ibm/xml/xlxp2/jaxb/unmarshal/AbstractUnmar
  shallerImpl.unmarshal(AbstractUnmarshallerImpl.java:81)
  4XESTACKTRACE at at/gv/brz/test/websphereunmarshaling/CrashReso
  urce.getMessage(CrashResource.java:28)
  4XESTACKTRACE at
  sun/reflect/NativeMethodAccessorImpl.invoke0(Native Method)
  4XESTACKTRACE at sun/reflect/NativeMethodAccessorImpl.invoke(Na
  tiveMethodAccessorImpl.java:90(CompiledCode))
  4XESTACKTRACE at sun/reflect/DelegatingMethodAccessorImpl.invok
  e(DelegatingMethodAccessorImpl.java:55(CompiledCode))
  4XESTACKTRACE at
  java/lang/reflect/Method.invoke(Method.java:508(Compiled Code))
  4XESTACKTRACE at com/ibm/ws/jaxrs20/server/LibertyJaxRsServerFa
  ctoryBean.performInvocation(LibertyJaxRsServerFactoryBean.java:
  659)
  4XESTACKTRACE at com/ibm/ws/jaxrs20/server/LibertyJaxRsInvoker.
  performInvocation(LibertyJaxRsInvoker.java:108)
  4XESTACKTRACE at org/apache/cxf/service/invoker/AbstractInvoker
  .invoke(AbstractInvoker.java:96)
  4XESTACKTRACE at com/ibm/ws/jaxrs20/server/LibertyJaxRsInvoker.
  invoke(LibertyJaxRsInvoker.java:174)
  4XESTACKTRACE at
  org/apache/cxf/jaxrs/JAXRSInvoker.invoke(JAXRSInvoker.java:191)
  
  Code snippet where the error occurs:
  JAXBContext jaxbContext =
  JAXBContext.newInstance(ObjectFactory.class);
  Unmarshaller jaxbUnmarshaller =
  jaxbContext.createUnmarshaller();
  NotificationMessage notificationMessage = (NotificationMessage)
  JAXBIntrospector.getValue(jaxbUnmarshaller .unmarshal(new
  StringReader(xmlString)));
  
  XML parser hangs in the last line and leads to a cpu loop caused
  by the four equal signs at the end of the Base64 string (instead
  of 2).
  

Local fix

• As possible way to avoid it would be to set
  com.ibm.xml.xlxp.jaxb.opti.level property set to 2
  to disable IBM unmarshaller and use reference implementation
  instead
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: PROCESSING BASE64 ENCODED DATA USING    *
  *                      JAXB                                    *
  *                      CAN CAUSE A LOOP                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When unamarshalling base64 encoded data inside XML using JAXB an
  infinite loop can occur.
  

Problem conclusion

• The fix for this APAR is targeted for inclusion in fix pack
  9.0.5.11 and 8.5.5.21. For more information, see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

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

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels