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Posted to hdfs-issues@hadoop.apache.org by "Daryn Sharp (JIRA)" <ji...@apache.org> on 2013/04/08 23:42:16 UTC

[jira] [Commented] (HDFS-4671) DFSAdmin fetchImage should require superuser privilege even when security is not enabled

    [ https://issues.apache.org/jira/browse/HDFS-4671?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13625861#comment-13625861 ] 

Daryn Sharp commented on HDFS-4671:
-----------------------------------

I can see the argument for this change, but the user can sidestep the authorization by setting the env HADOOP_USER_NAME=hdfs so I'm not sure there's much value.
                
> DFSAdmin fetchImage should require superuser privilege even when security is not enabled
> ----------------------------------------------------------------------------------------
>
>                 Key: HDFS-4671
>                 URL: https://issues.apache.org/jira/browse/HDFS-4671
>             Project: Hadoop HDFS
>          Issue Type: Bug
>    Affects Versions: 2.0.3-alpha
>            Reporter: Stephen Chu
>
> When security is not enabled, non-superusers can fetch the fsimage. This is problematic because the non-superusers can then process the fsimage for contents the user should not have access to.
> For example, schu is not a superuser and does not have access to hdfs://user/hdfs/. However, schu can still fetch the fsimage and run the OfflineImageViewer on the fsimage to examine the contents of hdfs://user/hdfs/.
> {code}
> [schu@hdfs-vanilla-1 images]$ hadoop fs -ls /user/hdfs
> ls: Permission denied: user=schu, access=READ_EXECUTE, inode="/user/hdfs":hdfs:supergroup:drwx------
> [schu@hdfs-vanilla-1 images]$ hdfs dfsadmin -fetchImage ~/images/
> 13/04/08 12:45:20 INFO namenode.TransferFsImage: Opening connection to http://hdfs-vanilla-1.ent.cloudera.com:50070/getimage?getimage=1&txid=latest
> 13/04/08 12:45:21 INFO namenode.TransferFsImage: Transfer took 0.91s at 91.61 KB/s
> [schu@hdfs-vanilla-1 images]$ hdfs oiv -i ~/images/fsimage_0000000000000947148 -o ~/images/oiv.out
> {code}
> When kerberos authentication is enabled, superuser privilege is enforced:
> {code}
> [testuser@hdfs-secure-1 ~]$ hdfs dfsadmin -fetchImage ~/images/
> 13/04/08 12:48:23 INFO namenode.TransferFsImage: Opening connection to http://hdfs-secure-1.ent.cloudera.com:50070/getimage?getimage=1&txid=latest
> 13/04/08 12:48:23 ERROR security.UserGroupInformation: PriviledgedActionException as:testuser@ENT.CLOUDERA.COM (auth:KERBEROS) cause:org.apache.hadoop.hdfs.server.namenode.TransferFsImage$HttpGetFailedException: Image transfer servlet at http://hdfs-secure-1.ent.cloudera.com:50070/getimage?getimage=1&txid=latest failed with status code 403
> Response message:
> Only Namenode, Secondary Namenode, and administrators may access this servlet
> fetchImage: Image transfer servlet at http://hdfs-secure-1.ent.cloudera.com:50070/getimage?getimage=1&txid=latest failed with status code 403
> Response message:
> Only Namenode, Secondary Namenode, and administrators may access this servlet
> [testuser@hdfs-secure-1 ~]$ 
> {code}
> We should still enforce checking privileges when kerberos authentication is disabled.

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