[HDFS-15628] HttpFS server throws NPE if a file is a symlink

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.2.2, 3.3.1, 3.4.0, 3.2.3
• Component/s: fs, httpfs
• Hadoop Flags: Reviewed
• Assignee: Ahmed Hussein
• Reporter: Ahmed Hussein
• Created: 13/Oct/20 01:26
• Updated: 10/Jun/21 07:44
• Resolved: 14/Oct/20 23:06

Description

If a directory containing a symlink is listed, the client (WebHfdsFileSystem) blows up with a NPE. If type is SYMLINK, there must be symlink field whose value is the link target string. HttpFS returns a response without symlink filed. WebHfdsFileSystem assumes it is there for a symlink and blindly tries to parse it, causing NPE.

This is not an issue if the destination cluster does not have symlinks enabled.

 

java.io.IOException: localhost:55901: Response decoding failure: java.lang.NullPointerException

	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$FsPathResponseRunner.getResponse(WebHdfsFileSystem.java:967)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$AbstractRunner.runWithRetry(WebHdfsFileSystem.java:816)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$AbstractRunner.access$100(WebHdfsFileSystem.java:638)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$AbstractRunner$1.run(WebHdfsFileSystem.java:676)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1899)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$AbstractRunner.run(WebHdfsFileSystem.java:672)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem.listStatus(WebHdfsFileSystem.java:1731)
	at org.apache.hadoop.fs.http.client.BaseTestHttpFSWith.testListSymLinkStatus(BaseTestHttpFSWith.java:388)
	at org.apache.hadoop.fs.http.client.BaseTestHttpFSWith.operation(BaseTestHttpFSWith.java:1230)
	at org.apache.hadoop.fs.http.client.BaseTestHttpFSWith.testOperation(BaseTestHttpFSWith.java:1363)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.apache.hadoop.test.TestHdfsHelper$HdfsStatement.evaluate(TestHdfsHelper.java:95)
	at org.apache.hadoop.test.TestDirHelper$1.evaluate(TestDirHelper.java:106)
	at org.apache.hadoop.test.TestExceptionHelper$1.evaluate(TestExceptionHelper.java:42)
	at org.apache.hadoop.test.TestJettyHelper$1.evaluate(TestJettyHelper.java:74)
	at org.apache.hadoop.test.TestDirHelper$1.evaluate(TestDirHelper.java:106)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
Caused by: java.lang.NullPointerException
	at org.apache.hadoop.hdfs.DFSUtilClient.string2Bytes(DFSUtilClient.java:116)
	at org.apache.hadoop.hdfs.web.JsonUtilClient.toFileStatus(JsonUtilClient.java:131)
	at org.apache.hadoop.hdfs.web.JsonUtilClient.toHdfsFileStatusArray(JsonUtilClient.java:215)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$15.decodeResponse(WebHdfsFileSystem.java:1723)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$15.decodeResponse(WebHdfsFileSystem.java:1719)
	at org.apache.hadoop.hdfs.web.WebHdfsFileSystem$FsPathResponseRunner.getResponse(WebHdfsFileSystem.java:962)
	... 46 more