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https://issues.apache.org/jira/browse/LOG4J2-2650?focusedWorklogId=272350&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-272350
]
ASF GitHub Bot logged work on LOG4J2-2650:
------------------------------------------
Author: ASF GitHub Bot
Created on: 04/Jul/19 19:43
Start Date: 04/Jul/19 19:43
Worklog Time Spent: 10m
Work Description: mattiabertorello commented on issue #290: [LOG4J2-2650]
Fix ArrayIndexOutOfBoundsException when the mac variable is an ipv6
URL: https://github.com/apache/logging-log4j2/pull/290#issuecomment-508564354
Yes you are right, I was not sure what part of the code fix.
Because I didn't think that the `NetUtils.getMacAddress` method should
return also an emulate MAC. In fact this line `mac = localHost.getAddress();`
was pretty obscure to me why was there.
In any case I replace it with these lines
```
// Emulate a mac address with an IP v4 or v6
final byte[] address = localHost.getAddress();
// Take only 6 bytes if the address is an IPv6 otherwise will pad with two
zero bytes
mac = Arrays.copyOf(address, 6);
```
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Issue Time Tracking
-------------------
Worklog Id: (was: 272350)
Time Spent: 0.5h (was: 20m)
> ArrayIndexOutOfBoundsException in the initialization of UuidUtil
> ----------------------------------------------------------------
>
> Key: LOG4J2-2650
> URL: https://issues.apache.org/jira/browse/LOG4J2-2650
> Project: Log4j 2
> Issue Type: Bug
> Components: Core
> Affects Versions: 2.12.0
> Environment: os : Mac OS
> java: 1.8 (jdk1.8.0_172.jdk)
> none network interfaces connected
> Reporter: Mattia Bertorello
> Priority: Major
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> Hi,
> I found a problem in the UuidUtil initialization.
> The code that generate the exception
> {code:java}
> private static Logger log = LogManager.getLogger(MyClass.class);
> {code}
> 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.
>
> [NetUtils.java#L108|https://github.com/apache/logging-log4j2/blob/da539329d528d979f4dd385a6ebb639793ef37bd/log4j-core/src/main/java/org/apache/logging/log4j/core/util/NetUtils.java#L108]
> {code:java}
> if (mac == null || mac.length == 0) {
> mac = localHost.getAddress();
> }
> {code}
> This is the part that generate the ArrayIndexOutOfBoundsException
>
> [UuidUtil.java#L81|https://github.com/apache/logging-log4j2/blob/da539329d528d979f4dd385a6ebb639793ef37bd/log4j-core/src/main/java/org/apache/logging/log4j/core/util/UuidUtil.java#L81]
> {code:java}
> System.arraycopy(mac, index, node, index + 2, length);{code}
> These 16 bytes will generate a wrong destination index that exceed the length
> of the node array.
> {noformat}
> mac = {byte[16]@3217}
> length = 6
> index = 10
> node = {byte[8]@3222}
> {noformat}
> This is the complete exception
> {code}
> 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
> {code}
> 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|https://github.com/apache/logging-log4j2/blob/da539329d528d979f4dd385a6ebb639793ef37bd/log4j-core/src/main/java/org/apache/logging/log4j/core/util/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|https://github.com/apache/logging-log4j2/blob/da539329d528d979f4dd385a6ebb639793ef37bd/log4j-core/src/main/java/org/apache/logging/log4j/core/util/UuidUtil.java#L81]
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