Michel Graciano created LOG4J2-2980:
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Summary: CLONE - ArrayIndexOutOfBoundsException in the
initialization of UuidUtil
Key: LOG4J2-2980
URL: https://issues.apache.org/jira/browse/LOG4J2-2980
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: Michel Graciano
Fix For: 2.12.1
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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