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https://issues.apache.org/jira/browse/HADOOP-15725?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16606317#comment-16606317
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Eric Yang commented on HADOOP-15725:
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I believe this is a non-Kerberos setup issue. In non-Kerberos cluster,
UserGroupInformation.isSecurityEnabled()==false, and it will by pass all
security check in Hadoop code base. Therefore, if you use
UserGroupInformation.createRemoteUser(), there is no security enforcing
impersonation check and allow the operation to be carried out as root user.
Try this on a Kerberos setup, and see if you get the same result. Same
operation shouldn't work on Kerberos enabled cluster.
> FileSystem.deleteOnExit should check user permissions
> -----------------------------------------------------
>
> Key: HADOOP-15725
> URL: https://issues.apache.org/jira/browse/HADOOP-15725
> Project: Hadoop Common
> Issue Type: Bug
> Reporter: Oleksandr Shevchenko
> Priority: Major
> Labels: Security
> Attachments: deleteOnExitReproduce
>
>
> For now, we able to add any file to FileSystem deleteOnExit list. It leads to
> security problems. Some user (Intruder) can get file system instance which
> was created by another user (Owner) and mark any files to delete even if
> "Intruder" doesn't have any access to this files. Later when "Owner" invoke
> close method (or JVM is shut down since we have ShutdownHook which able to
> close all file systems) marked files will be deleted successfully since
> deleting was do behalf of "Owner" (or behalf of a user who ran a program).
> I attached the patch [^deleteOnExitReproduce] which reproduces this
> possibility and also I able to reproduce it on a cluster with both Local and
> Distributed file systems:
> {code:java}
> public class Main {
> public static void main(String[] args) throws Exception {
> final FileSystem fs;
> Configuration conf = new Configuration();
> conf.set("fs.default.name", "hdfs://node:9000");
> conf.set("fs.hdfs.impl",
> org.apache.hadoop.hdfs.DistributedFileSystem.class.getName()
> );
> fs = FileSystem.get(conf);
> System.out.println(fs);
> Path f = new Path("/user/root/testfile");
> System.out.println(f);
> UserGroupInformation hive = UserGroupInformation.createRemoteUser("hive");
> hive.doAs((PrivilegedExceptionAction<Boolean>) () -> fs.deleteOnExit(f));
> fs.close();
> }
> {code}
> Result:
> {noformat}
> root@node:/# hadoop fs -put testfile /user/root
> root@node:/# hadoop fs -chmod 700 /user/root/testfile
> root@node:/# hadoop fs -ls /user/root
> Found 1 items
> -rw------- 1 root supergroup 0 2018-09-06 18:07 /user/root/testfile
> root@node:/# java -jar testDeleteOther.jar
> log4j:WARN No appenders could be found for logger
> (org.apache.hadoop.conf.Configuration.deprecation).
> log4j:WARN Please initialize the log4j system properly.
> log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more
> info.
> DFS[DFSClient[clientName=DFSClient_NONMAPREDUCE_309539034_1, ugi=root
> (auth:SIMPLE)]]
> /user/root/testfile
> []
> root@node:/# hadoop fs -ls /user/root
> root@node:/#
> {noformat}
> We should add a check user permissions before mark a file to delete.
> Could someone evaluate this? And if no one objects I would like to start
> working on this.
> Thanks a lot for any comments.
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