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  1. Log4j 2
  2. LOG4J2-2980

CLONE - ArrayIndexOutOfBoundsException in the initialization of UuidUtil



    • Bug
    • Status: Closed
    • Major
    • Resolution: Duplicate
    • 2.12.1
    • 2.12.1
    • Core
    • None
    • os : Mac OS

      java: 1.8 (jdk1.8.0_172.jdk)

      none network interfaces connected



      I have cloned the old issue because the patch was not integrated. It should be fixed again. Should I send a PR again?



      I found a problem in the UuidUtil initialization.

      The code that generate the exception

        private static Logger log = LogManager.getLogger(MyClass.class);

      This code return a ip address of localhost and when the stack is IPv4 return 4 bytes but when the default stack is IPv6 it's going to return 16 bytes.

      if (mac == null || mac.length == 0) { 
         mac = localHost.getAddress(); 

      This is the part that generate the ArrayIndexOutOfBoundsException


      System.arraycopy(mac, index, node, index + 2, length);

      These 16 bytes will generate a wrong destination index that exceed the length of the node array.

      mac = {byte[16]@3217} 
      length = 6 
      index = 10 
      node = {byte[8]@3222}

      This is the complete exception  

      java.lang.ExceptionInInitializerError at org.apache.logging.log4j.core.util.WatchManager.<init>(WatchManager.java:53) at org.apache.logging.log4j.core.config.AbstractConfiguration.<init>(AbstractConfiguration.java:135) at org.apache.logging.log4j.core.config.NullConfiguration.<init>(NullConfiguration.java:32) at org.apache.logging.log4j.core.LoggerContext.<clinit>(LoggerContext.java:79) at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.createContext(ClassLoaderContextSelector.java:171) at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.locateContext(ClassLoaderContextSelector.java:145) at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:70) at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:57) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:148) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45) at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194) at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:581) at cc.arduino.contributions.packages.ContributionInstaller.<clinit>(ContributionInstaller.java:66) at processing.app.Base.<init>(Base.java:291) at processing.app.Base.main(Base.java:150) Caused by: java.lang.ArrayIndexOutOfBoundsException at java.lang.System.arraycopy(Native Method) at org.apache.logging.log4j.core.util.UuidUtil.<clinit>(UuidUtil.java:81) ... 15 more

      To reproduce the exception you need

      • disconnect every network interface
      • verify that java will use the IPv6 stack -Djava.net.preferIPv4Stack=false -Djava.net.preferIPv6Addresses=true
      • Initialize a log of log4j

      I suggest different solution:

      • Remove  NetUtils.java#L108 and return always null (when the other code fail to init the mac variable ) because in general the method is called getMacAddress but in that particular case will return and IP address 
      • Mange the IPv6 case in the static part of the class UuidUtil UuidUtil.java#L81


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              Unassigned Unassigned
              michel.graciano Michel Graciano
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