CentOS - Nov 2018 - Tools/mechanisms for the management of access permissions in big filebased datasets

Thank you.  Basically our problem are not the ACLs or their support per 
se, but that we have to manage a huge number of individual ACLS (several 
hundred users in more than hundred projects) in multi-petabyte 
filesystem and still have to keep overview and control.  Our problem is 
more the management side.  Effectively we are looking for a tool that 
helps us manage these permissions and we would accept whatever 
permissions mechanism this tool uses (UGO/ACLs).

Cheers
frank


On 11/27/2018 03:06 PM, Leroy Tennison wrote:
> Well, there are extended ACLs if they're available in CentOS, when I
first worked with them (long ago) they were new (and on a different Distro).  I
hope support for them has improved.  They allow multiple users/groups to be
assigned permissions to a file/directory.  The problem then was that chmod (and
other programs) were not extended-ACL-aware and could over-ride extended ACLs. 
There was a mechanism to recover from the situation but what it basically came
down to was eternal vigilance - the system administrators had to understand (and
agree about) extended ACLs and be careful/diligent in applying them.  There are
hacks which could possibly help (rename chmod and replace it with a script
warning about extended ACLs) but, in the final analysis, it's not a decision
to be undertaken lightly (unless the situation has changed dramatically).
> 
> 
> Leroy Tennison
> Network Information/Cyber Security Specialist
> E: leroy at datavoiceint.com
> 2220 Bush Dr
> McKinney, Texas
> 75070
> www.datavoiceint.com
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> ________________________________________
> From: CentOS <centos-bounces at centos.org> on behalf of Frank
Thommen <list.centos at drosera.ch>
> Sent: Tuesday, November 27, 2018 7:25 AM
> To: CentOS mailing list
> Subject: [EXTERNAL] [CentOS] Tools/mechanisms for the management of access
permissions in big filebased datasets
> 
> Hello,
> 
> we are currently managing access permissions through classical
> user-group-others permissions on a multi-petabyte directory tree with
> partially very deep and broad directories.  Projects are represented by
> directory trees and mapped through GIDs.  Lately we had lots of
> "singular" permission request (one single user needs access to a
single
> dataset but should not be able to see all other datasets belonging to
> the same project).  We realized, that the UGO model doesn't scale and
is
> becoming more and more unmanageable.
> 
> Can you recommend tools/mechanisms/technologies to overcome the
> drawbacks of the UGO model?  We are thinking about some purely ACL based
> mechanism (but are open to other ideas).  All filesystems in question
> are mounted via NFSv4 and the clients are (almost) completely CentOS 7.x
> hsots.  Ideally the tool would have some web UI and some kind of
> (REST)API which allows us to modify permissions from our inhouse data
> management application (which does /not/ manage permissions, just the
> structure of the data).  Additionally it should be able to
> visualize/report permissions in directory.
> 
> I wasn't very successful in googling possible candidates, hence the
> question to the list.
> 
> Cheers
> frank
> 
> 
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On Nov 28, 2018, at 2:36 AM, Frank Thommen <list.centos at drosera.ch>
wrote:
> 
> Our problem is more the management side.  Effectively we are looking for a
tool that helps us manage these permissions
I want ACLs to work.  There?s a real problem to solve, which is that the old
user:group rwx Unix permission system doesn?t let you express common wishes like
?Angel & Bobby own this file, and groups Cookie and Danish can read and
write it, and user Egbert can write it.?

The problem is, ACLs are hidden by default with respect to ?ls -l?, and when you
do make them visible with getfacl, you now have a complex mental parsing problem
to solve before you understand the meaning of the ACL.  Add in ACL inheritance
and you?ve got a real mess.

Make a facility hidden and complex, and you pretty much guarantee that few will
use that facility, and those who do will at times create messes they can?t
properly understand.  A security mechanism that?s most often underused,
misapplied, or both is a bad system.

FOSS is good at solving such problems, so the only way I can see that tools to
solve this problem don?t exist is that few actually use ACLs, perhaps because of
the reasons above.

Who here uses ACLs to good effect?  Are you using more than just getfacl/setfacl
to do it?

On Wed, 28 Nov 2018, Warren Young wrote:
> Who here uses ACLs to good effect?  Are you using more than just 
> getfacl/setfacl to do it?
We use NFSv4 ACLs on Lustre and Isilon filesystems, so we employ 
nfs4_getfacl and nfs4_setfacl -- but all of our work is done on the 
command line, not via a GUI and larger management tool.

Our best practice is to script up the ACLs so they can be reapplied in 
case they get deleted or inappropriately changed. My current scripting 
logic usually writes the desired ACLs to temp files and deploys them 
in one swoop.

Take the following case:

owner: bob
read-write group: boblab
read-only group: alicelab
target directory: /srv/group/boblab

A skeleton version of the script would look something like this

# define directory-level ACL and write to temp file
cat <<__DIRACL__ > /tmp/diracl
A::OWNER@:rwaDdxtTnNcCoy
A::GROUP@:rwaDxtTnNcy
A::EVERYONE@:tncy
A:fdg:boblab at domain.com:RWX
A:fdg:alicelab at domain.com:RX
__DIRACL__

# define file-level ACL and write to temp file
cat <<__FILEACL__ > /tmp/fileacl
A::OWNER@:rwaDdxtTnNcCoy
A::GROUP@:rwaDxtTnNcy
A::EVERYONE@:tncy
A:g:boblab at domain.com:RWX
A:g:alicelab at domain.com:RX
__FILEACL__

# apply ownership, perms, and ACLs.
chown -R bob:boblab /srv/group/boblab
chmod -R ug+rw,o-rwx /srv/group/boblab
find /srv/group/boblab -type d \
   -exec nfs4_setfacl -S /tmp/diracl {} \;
find /srv/group/boblab -type f \
   -exec nfs4_setfacl -S /tmp/fileacl {} \;


Once the directory ACLs are applied, any new files created within 
those directories should inherit the proper ACLs.

-- 
Paul Heinlein
heinlein at madboa.com
45?38' N, 122?6' W