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https://issues.apache.org/jira/browse/HDFS-6962?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15383330#comment-15383330
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Chris Nauroth commented on HDFS-6962:
-------------------------------------
bq. One additional question before responding to your comments. I added
getMasked and getUnmasked with default implementations to FsPermission which is
public and stable. Is that ok? The alternative to this approach is to use
instanceof to detect FsCreateModes object with an FsPermission reference.
Adding new methods to a public/stable class is acceptable according to [Apache
Hadoop
Compatibility|http://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-common/Compatibility.html]
guidelines. We took a similar approach when adding the ACL bit. We added
{{FsPermission#getAclBit}} with a default implementation. The HDFS-specific
{{FsPermissionExtension}} subclass overrides that method.
bq. I think it is ok. Will it affect our plan to backport the fix to CDH
branches based on 2.6.0?
I can't comment definitively on CDH concerns, but I expect that any distro
could make the choice to apply the patch to prior maintenance lines if they
come to a different risk assessment decision. The ACL code changes
infrequently at this point, so I expect it would be trivial to backport, with
low likelihood of complex merge conflicts.
> ACLs inheritance conflict with umaskmode
> ----------------------------------------
>
> Key: HDFS-6962
> URL: https://issues.apache.org/jira/browse/HDFS-6962
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: security
> Affects Versions: 2.4.1
> Environment: CentOS release 6.5 (Final)
> Reporter: LINTE
> Assignee: John Zhuge
> Priority: Critical
> Labels: hadoop, security
> Attachments: HDFS-6962.001.patch, HDFS-6962.002.patch,
> HDFS-6962.003.patch, HDFS-6962.004.patch, HDFS-6962.005.patch,
> HDFS-6962.006.patch, HDFS-6962.1.patch, disabled_new_client.log,
> disabled_old_client.log, enabled_new_client.log, enabled_old_client.log, run
>
>
> In hdfs-site.xml
> <property>
> <name>dfs.umaskmode</name>
> <value>027</value>
> </property>
> 1/ Create a directory as superuser
> bash# hdfs dfs -mkdir /tmp/ACLS
> 2/ set default ACLs on this directory rwx access for group readwrite and user
> toto
> bash# hdfs dfs -setfacl -m default:group:readwrite:rwx /tmp/ACLS
> bash# hdfs dfs -setfacl -m default:user:toto:rwx /tmp/ACLS
> 3/ check ACLs /tmp/ACLS/
> bash# hdfs dfs -getfacl /tmp/ACLS/
> # file: /tmp/ACLS
> # owner: hdfs
> # group: hadoop
> user::rwx
> group::r-x
> other::---
> default:user::rwx
> default:user:toto:rwx
> default:group::r-x
> default:group:readwrite:rwx
> default:mask::rwx
> default:other::---
> user::rwx | group::r-x | other::--- matches with the umaskmode defined in
> hdfs-site.xml, everything ok !
> default:group:readwrite:rwx allow readwrite group with rwx access for
> inhéritance.
> default:user:toto:rwx allow toto user with rwx access for inhéritance.
> default:mask::rwx inhéritance mask is rwx, so no mask
> 4/ Create a subdir to test inheritance of ACL
> bash# hdfs dfs -mkdir /tmp/ACLS/hdfs
> 5/ check ACLs /tmp/ACLS/hdfs
> bash# hdfs dfs -getfacl /tmp/ACLS/hdfs
> # file: /tmp/ACLS/hdfs
> # owner: hdfs
> # group: hadoop
> user::rwx
> user:toto:rwx #effective:r-x
> group::r-x
> group:readwrite:rwx #effective:r-x
> mask::r-x
> other::---
> default:user::rwx
> default:user:toto:rwx
> default:group::r-x
> default:group:readwrite:rwx
> default:mask::rwx
> default:other::---
> Here we can see that the readwrite group has rwx ACL bu only r-x is effective
> because the mask is r-x (mask::r-x) in spite of default mask for inheritance
> is set to default:mask::rwx on /tmp/ACLS/
> 6/ Modifiy hdfs-site.xml et restart namenode
> <property>
> <name>dfs.umaskmode</name>
> <value>010</value>
> </property>
> 7/ Create a subdir to test inheritance of ACL with new parameter umaskmode
> bash# hdfs dfs -mkdir /tmp/ACLS/hdfs2
> 8/ Check ACL on /tmp/ACLS/hdfs2
> bash# hdfs dfs -getfacl /tmp/ACLS/hdfs2
> # file: /tmp/ACLS/hdfs2
> # owner: hdfs
> # group: hadoop
> user::rwx
> user:toto:rwx #effective:rw-
> group::r-x #effective:r--
> group:readwrite:rwx #effective:rw-
> mask::rw-
> other::---
> default:user::rwx
> default:user:toto:rwx
> default:group::r-x
> default:group:readwrite:rwx
> default:mask::rwx
> default:other::---
> So HDFS masks the ACL value (user, group and other -- exepted the POSIX
> owner -- ) with the group mask of dfs.umaskmode properties when creating
> directory with inherited ACL.
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