Harsh J created HADOOP-8845:
-------------------------------

             Summary: When looking for parent paths info, globStatus must 
filter out non-directory elements to avoid an AccessControlException
                 Key: HADOOP-8845
                 URL: https://issues.apache.org/jira/browse/HADOOP-8845
             Project: Hadoop Common
          Issue Type: Bug
          Components: fs
    Affects Versions: 2.0.0-alpha
            Reporter: Harsh J
            Assignee: Harsh J


A brief description from my colleague Stephen Fritz who helped discover it:

{quote}
[root@node1 ~]# su - hdfs
-bash-4.1$ echo "My Test String">testfile <-- just a text file, for testing 
below
-bash-4.1$ hadoop dfs -mkdir /tmp/testdir <-- create a directory
-bash-4.1$ hadoop dfs -mkdir /tmp/testdir/1 <-- create a subdirectory
-bash-4.1$ hadoop dfs -put testfile /tmp/testdir/1/testfile <-- put the test 
file in the subdirectory
-bash-4.1$ hadoop dfs -put testfile /tmp/testdir/testfile <-- put the test file 
in the directory
-bash-4.1$ hadoop dfs -lsr /tmp/testdir
drwxr-xr-x   - hdfs hadoop          0 2012-09-25 06:52 /tmp/testdir/1
-rw-r--r--   3 hdfs hadoop         15 2012-09-25 06:52 /tmp/testdir/1/testfile
-rw-r--r--   3 hdfs hadoop         15 2012-09-25 06:52 /tmp/testdir/testfile
All files are where we expect them...OK, let's try reading

-bash-4.1$ hadoop dfs -cat /tmp/testdir/testfile
My Test String <-- success!

-bash-4.1$ hadoop dfs -cat /tmp/testdir/1/testfile
My Test String <-- success!

-bash-4.1$ hadoop dfs -cat /tmp/testdir/*/testfile
My Test String <-- success!  
Note that we used an '*' in the cat command, and it correctly found the 
subdirectory '/tmp/testdir/1', and ignore the regular file 
'/tmp/testdir/testfile'

-bash-4.1$ exit
logout
[root@node1 ~]# su - testuser <-- lets try it as a different user:
[testuser@node1 ~]$ hadoop dfs -lsr /tmp/testdir
drwxr-xr-x   - hdfs hadoop          0 2012-09-25 06:52 /tmp/testdir/1
-rw-r--r--   3 hdfs hadoop         15 2012-09-25 06:52 /tmp/testdir/1/testfile
-rw-r--r--   3 hdfs hadoop         15 2012-09-25 06:52 /tmp/testdir/testfile
[testuser@node1 ~]$ hadoop dfs -cat /tmp/testdir/testfile
My Test String <-- good

[testuser@node1 ~]$ hadoop dfs -cat /tmp/testdir/1/testfile
My Test String <-- so far so good

[testuser@node1 ~]$ hadoop dfs -cat /tmp/testdir/*/testfile
cat: org.apache.hadoop.security.AccessControlException: Permission denied: 
user=testuser, access=EXECUTE, 
inode="/tmp/testdir/testfile":hdfs:hadoop:-rw-r--r--
{code}

Essentially, we hit a ACE with access=EXECUTE on file /tmp/testdir/testfile 
cause we tried to access the /tmp/testdir/testfile/testfile as a path. This 
shouldn't happen, as the testfile is a file and not a path parent to be looked 
up upon.

Surprisingly the superuser avoids hitting into the error, as a result of 
bypassing permissions, but that can be looked up on another JIRA - if it is 
fine to let it be like that or not.

This JIRA targets a client-sided fix to not cause such /path/file/dir kinda 
lookups.

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