|
|
| Line 78: |
Line 78: |
| | in [[Access control for the LFC]]. | | in [[Access control for the LFC]]. |
| | $ srm-get-permissions $SRM/myfile | | $ srm-get-permissions $SRM/myfile |
| − | # file : srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/pvier/janjust/myfile | + | srm-get-permissions $SRM/myfile |
| − | # owner : 18010 | + | Return code: SRM_NOT_SUPPORTED |
| − | owner:18010:RW
| + | Explanation: Not supported |
| − | user:18010:RW
| |
| − | group:1276:R
| |
| − | other:R | |
| | | | |
| − | Just for the fun of it, let's list a file which we did not create ourselves:
| + | permissions array is null |
| − | $ srm-get-permissions srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/pvier/ronstestdir3 | |
| − | # file : srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/pvier/ronstestdir3
| |
| − | # owner : 18010
| |
| − | owner:18010:RWX
| |
| − | user:18010:RWX
| |
| − | group:1276:NONE
| |
| − | other:NONE
| |
| − | Wait a second... that file has '''exactly''' the same user (18010) and group (1276) !
| |
| | | | |
| − | Now let's check a directory that was created using a different VOMS proxy, this time one for VO <tt>vlemed</tt>:
| |
| − | $ srm-get-permissions srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/vlemed/generated/2007-11-07
| |
| − | # file : srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/vlemed/generated/2007-11-07
| |
| − | # owner : 18002
| |
| − | owner:18002:RWX
| |
| − | user:18002:RWX
| |
| − | group:1276:RX
| |
| − | other:RX
| |
| − | This time the user is different (18002) but the group is still 1276 !
| |
| − | We will have to keep this in mind when we want to limit access to our files.
| |
| | | | |
| − | '''Note''': this limitation is due to the setup of the dCache storage system at SARA, where <tt>pnfs</tt> is used as | + | '''Uh-oh... it looks like StoRM does not support permissions or access control''' |
| − | the underlying file system.
| |
| − | <tt>pnfs</tt> does not support user-level access control. An alternative is to use <tt>chimera</tt> as the underlying
| |
| − | file system, which does support user-level ACLs, but this would require a migration of '''all''' data currently in
| |
| − | dCache, as well as a (manual) re-synchronization between dCache and all LFCs that have entries pointing to dCache.
| |
| | | | |
| | = Modifying the permissions = | | = Modifying the permissions = |
| | | | |
| − | Use
| + | ''' Not supported ''' |
| − | srm-set-permissions -h
| |
| − | to get a list of options for this command.
| |
| − | $ srm-set-permissions -type=CHANGE -group=NONE -other=NONE $SRM/myfile
| |
| − | (this command does not return any output on success)
| |
| − | | |
| − | '''Note''' that we have set the group permissions to <NONE> . If we do not do this then users from other VOs can still read the file. | |
| − | | |
| − | = Verifying access control =
| |
| − | | |
| − | As the original user:
| |
| − | $ srm-get-permissions $SRM/myfile
| |
| − | # file : srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/pvier/janjust/myfile
| |
| − | # owner : 18010
| |
| − | owner:18010:RW
| |
| − | user:18010:RW
| |
| − | group:1276:NONE
| |
| − | other:NONE
| |
| − | | |
| − | Now if we switch to another VO:
| |
| − | | |
| − | $ voms-proxy-init --voms vlemed
| |
| − | Enter GRID pass phrase:
| |
| − | Your identity: /O=dutchgrid/O=users/O=nikhef/CN=Jan Just Keijser
| |
| − | Creating temporary proxy .......................................... Done
| |
| − | Contacting voms.grid.sara.nl:30003 [/O=dutchgrid/O=hosts/OU=sara.nl/CN=voms.grid.sara.nl] "vlemed" Done
| |
| − | Creating proxy ............................. Done
| |
| − | Your proxy is valid until Thu Aug 6 23:45:56 2009
| |
| − | and then try to copy the file
| |
| − | $ srmcp $SRM/myfile file:///$PWD/blah
| |
| − | Thu Aug 06 11:46:41 CEST 2009: rs.state = Failed rs.error = at Thu Aug 06 11:46:36 CEST 2009 state Pending :
| |
| − | created RequestFileStatus#-2083337326 failed with error:[ at Thu Aug 06 11:46:36 CEST 2009 state Failed :
| |
| − | user AR:3209444168817257963 vlemed /O=dutchgrid/O=users/O=nikhef/CN=Jan Just Keijser 18002
| |
| − | read-write 0 / / < 1 groupLists : GL:/vlemed 1 groups : [1276,]; >cannot read 00190000000000000018C718]
| |
| − |
| |
| − | Thu Aug 06 11:46:41 CEST 2009: java.io.IOException: rs.state = Failed rs.error = at Thu Aug 06 11:46:36
| |
| − | CEST 2009 state Pending : created
| |
| − | RequestFileStatus#-2083337326 failed with error:[ at Thu Aug 06 11:46:36 CEST 2009 state Failed :
| |
| − | user AR:3209444168817257963 vlemed /O=dutchgrid/O=users/O=nikhef/CN=Jan Just Keijser 18002
| |
| − | read-write 0 / / < 1 groupLists : GL:/vlemed 1 groups : [1276,]; >cannot read 00190000000000000018C718]
| |
| − |
| |
| − | srm copy of at least one file failed or not completed
| |
| − | | |
| − | We can no longer access the file: success!
| |
| − | | |
| − | '''Notes'''
| |
| − | * it currently is '''not''' possible with dCache PNFS to restrict access to a file for your fellow VO-members.
| |
| − | * the dCache server has mapped the voms proxy to a different user (18002), which causes the <tt>srmcp</tt> request to fail. Thus dCache user+group mappings are slightly different from UNIX user+group mappings:
| |
| − | ** user+group1 = dcache_user1
| |
| − | ** user+group2 = dcache_user2
| |
| − | whereas on a regular UNIX filesystem you can always access a file that is owned by you, regardless of the
| |
| − | groupid of the file.
| |
| − | | |
| − | = Making files inaccessible to your VO =
| |
| − | Here's a quick guide on how to make file inaccessible to your VO, including yourself:
| |
| − | * Change the permissions of the file to '''author=NONE, group=RWX''':
| |
| − | srm-set-permissions -type=CHANGE -group=RWX -owner=NONE $SRM/myfile
| |
| − | * Verify:
| |
| − | $ srm-get-permissions $SRM/myfile
| |
| − | # file : srm://srm.grid.sara.nl/pnfs/grid.sara.nl/data/pvier/janjust/myfile
| |
| − | # owner : 18010
| |
| − | owner:18010:NONE
| |
| − | user:18010:NONE
| |
| − | group:1276:RWX
| |
| − | other:NONE
| |
| − | * Now try to read it:
| |
| − | $ srmcp -globus_tcp_port_range=20000,25000 $SRM/myfile file:///$PWD/blah
| |
| − | org.globus.ftp.exception.ServerException: Server refused performing the request.
| |
| − | Custom message: (error code 1)
| |
| − | [Nested exception message: Custom message: Unexpected reply: 550 Permission denied].
| |
| − | Nested exception is org.globus.ftp.exception.UnexpectedReplyCodeException:
| |
| − | Custom message: Unexpected reply: 550 Permission denied
| |
| − | at org.globus.ftp.vanilla.TransferMonitor.run(TransferMonitor.java:195)
| |
| − | at org.globus.ftp.vanilla.TransferMonitor.start(TransferMonitor.java:109)
| |
| − | at org.globus.ftp.FTPClient.transferRunSingleThread(FTPClient.java:1457)
| |
| − | at org.globus.ftp.FTPClient.get2(FTPClient.java:1724)
| |
| − | at org.dcache.srm.util.GridftpClient$TransferThread.run(GridftpClient.java:951)
| |
| − | at java.lang.Thread.run(Thread.java:619)
| |
| − | GridftpClient: transfer exception
| |
| − | org.globus.ftp.exception.ServerException: Server refused performing the request.
| |
| − | [SNIP]
| |
| − | so we can no longer read our own file. Now if we switch to another VO:
| |
| − | $ voms-proxy-init --voms vlemed
| |
| − | Enter GRID pass phrase:
| |
| − | Your identity: /O=dutchgrid/O=users/O=nikhef/CN=Jan Just Keijser
| |
| − | Creating temporary proxy .......................................... Done
| |
| − | Contacting voms.grid.sara.nl:30003 [/O=dutchgrid/O=hosts/OU=sara.nl/CN=voms.grid.sara.nl] "vlemed" Done
| |
| − | Creating proxy ............................. Done
| |
| − | Your proxy is valid until Thu Aug 6 23:45:56 2009
| |
| − | and then try to copy the file
| |
| − | $ srmcp -globus_tcp_port_range=20000,25000 $SRM/myfile file:///$PWD/blah
| |
| − | we '''do''' get a copy of the file.
| |
This page is part of an investigation on How to control access rights for LFC/SRM files .
Finding out how storage is organized
To list the storage systems to which you have access use
lcg-infosites --vo <YOUR-VO> se
which results in
Avail Space(Kb) Used Space(Kb) Type SEs
----------------------------------------------------------
12078 108 n.a srm.grid.rug.nl
12078 108 n.a srm.grid.rug.nl
730582644 681194097 n.a gb-se-amc.amc.nl
8226695519985 23304480014 n.a srm.grid.sara.nl
605355546 806421195 n.a gb-se-nki.els.sara.nl
6575746866 20920246 n.a carme.htc.biggrid.nl
152913518 115521938 n.a se.grid.rug.nl
248345185 1166074827 n.a gb-se-ams.els.sara.nl
355230761 1056545980 n.a gb-se-uu.science.uu.nl
1266740857 145035883 n.a gb-se-wur.els.sara.nl
337812899 1076607113 n.a gb-se-kun.els.sara.nl
2195706454 3048365 n.a tbn18.nikhef.nl
771834491 620488567 n.a gb-se-lumc.lumc.nl
Note the current version of the lcg-infosites command does not use your grid proxy at all !
You can then try to use the srmls command to figure out how the storage is organized:
$ srmls -l srm://srm.grid.rug.nl/
SRMClientV2 : srmLs: try # 0 failed with error
SRMClientV2 : ; nested exception is:
java.net.NoRouteToHostException: No route to host
SRMClientV2 : srmLs: try again
Ah, the SRM server is listening on a different port. Storm documentation suggests using port 8444:
$ srmls -l srm://srm.grid.rug.nl:8444/
srm client error:
java.lang.Exception: Return status:
- Status code: SRM_FAILURE
- Explanation: All requests failed
Progress, more or less...
By looking at a file that was previously stored on srm.grid.rug.nl (using lcg-lr) we guess that the directory structure starts with the VO:
$ srmls srm://srm.grid.rug.nl:8444/pvier/
0 /pvier/
0 /pvier/vletgenerated
0 /pvier/generated
Indeed, we're at the VO level.
Creating your own directory in SRM-space
Before we copy a file to the dCache SRM we first create our own directory. If we do not do this then SRM will
store the files in generated directories, over which we have little or no control.
srmmkdir srm://srm.grid.rug.nl:8444/pvier/janjust
The URL for this directory will be used throughout the rest of this page, hence we abbreviate it to
SRM=srm://srm.grid.rug.nl:8444/pvier/janjust
Copying and registering your file
Next we will copy a file to our SRM directory and register it in the LFC in one go:
$ lcg-cr -d $SRM/myfile -l lfn:/grid/pvier/janjust/my-storm-file file://$PWD/myfile
guid:1601bad4-c236-4f01-a4fb-54e12c7dc0a9
which returns the LFC GUID for the file upon success.
(For details on how to find out how the LFC directory space is organized see Access control for the LFC)
We could also have copied the file to the SRM only, bypassing the LFC registration, using the command
lcg-cp file://$PWD/myfile $SRM/myfile
or even
srmcp -globus_tcp_port_range=20000,25000 file://$PWD/myfile $SRM/myfile
but as we needed the LFC entry as well we used the (preferred) lcg-cr command. Please also note
that the srmcp command is not very well supported.
Looking at the permissions
For a file that is copied to an SRM and that is registered in the LFC there are 2 sets of permissions:
- SRM-level
- LFC-level
These permissions are not directly related to each other and need to be modified separately.
In this section we explain how to modify the SRM-level permissions. The LFC-level permissions are explained
in Access control for the LFC.
$ srm-get-permissions $SRM/myfile
srm-get-permissions $SRM/myfile
Return code: SRM_NOT_SUPPORTED
Explanation: Not supported
permissions array is null
Uh-oh... it looks like StoRM does not support permissions or access control
Modifying the permissions
Not supported
