SAC:LDAP

OSGeo endevours to offer a "single signon" for OSGeo services.

It is currently used for Subversion, Trac, Drupal, QGIS services (hub.qgis.org and plugins.qgis.org), Gitea and shell access (opt-in).

It is hoped to also use it for mediawiki and possibly some other services in the future.

LDAP management is the responsibility of SAC (the System Administration Committee).

LDAP Server (OpenLDAP)

The userid database is kept in LDAP on ldap.osgeo.org (secure vm). It is served by OpenLDAP (OpenLDAP Admin Guide).

The ldap daemon can manipulated as 'root' user with,

$ /etc/init.d/slapd [start|stop|restart]

The main ldap config file is,

/etc/ldap/slapd.conf

IP access filter is set by:

/etc/init.d/ipfilter 

To see detailed logging for ldap, change "loglevel 1" to "loglevel 3" in /etc/ldap/slapd.conf, restart the service and watch /var/log/debug. But be careful leaving it like this too long, the log grows quickly and is not rotated.

LDAP structure

Currently ldap structure is pretty basic. The purpose for keeping this structure simple is to allow for a more complex structure to be evolved as ldap becomes increasingly integrated into the full osgeo systems structure.

• dc=osgeo,dc=org
  • cn=Manager
  • ou=people
    • Separate entity for each user

  uid=login,ou=people,dc=osgeo,dc=org

  objectClass=inetOrgPerson

  cn=firstName lastName

  sn=lastName

  uid=login

  mail=email@address

  userPassword={md5}YPTyViiMKhiuWKEmFUOKLA==

  Also contains posixAccount and shadowAccount fields if this account is login enabled.

  • ou=projects,dc=osgeo,dc=org

  objectClass=organizationalUnit

  ou=project

  description=separate entity for each osgeo project with list of members

  • • Separate entity for each project group

  cn=admin,ou=projects,dc=osgeo,dc=org

  objectClass=groupOfNames

  cn=admin

  description=osgeo sysadmin group

  • ou=svn

  objectClass=organizationalUnit

  ou=svn

  description=separate entity for each repository with list of members with commit rights

  • • separate entity for each svn group (for example FDO)

  cn=fdo,ou=svn,dc=osgeo,dc=org

  objectClass=groupOfNames

  cn=fdo

  member= dn of member

  • ou=Shell (parent for "login" groups)

  description=NextUID:nnnnn (the next unix uidNumber value to assign)

  • • cn=telascience,ou=Shell,dc=osgeo,dc=org (list of all userids with telascience login access)

  uniqueMember=dn of member

Example ldif file

   version: 1

   dn: dc=osgeo,dc=org
   objectClass: dcObject
   objectClass: organization
   description: OSGeo ldap dit
   o: OSGeo
   dc: osgeo

   dn: cn=Manager,dc=osgeo,dc=org
   objectClass: organizationalRole
   cn: Manager

   dn: ou=people,dc=osgeo,dc=org
   ou: people
   description: all users of osgeo
   objectClass: organizationalUnit

   dn: uid=jsmith,ou=people,dc=osgeo,dc=org
   objectClass: inetOrgPerson
   uid: jsmith
   cn: Jon Smith
   sn: Smith 
   givenName: Jon
   mail: jsmith@somewhere.com
   userPassword: {md5}5Or4zfzGqo3jh/6iIUgKcA==

   dn: uid=jbrown,ou=people,dc=osgeo,dc=org
   objectClass: inetOrgPerson
   uid: jbrown
   cn: Jane Brown
   sn: Brown
   givenName: Jane 
   mail: jbrown@someotherplace.com
   userPassword: {md5}1iWhTyvkK2m4Uuar+Dp/IA==

   dn: ou=projects,dc=osgeo,dc=org
   ou: projects
   description: separate entity for each osgeo project with list of members
   objectClass: organizationalUnit

   dn: cn=admin,ou=projects,dc=osgeo,dc=org
   cn: admin
   description: osgeo sysadmin group
   objectClass: groupOfNames
   member: uid=jbrown,ou=people,dc=osgeo,dc=org
   member: uid=jsmith,ou=people,dc=osgeo,dc=org

   dn: ou=svn,dc=osgeo,dc=org
   ou: svn
   description: separate entity for for each repository.list of members with commit rights
   objectClass: organizationalUnit

   dn: cn=fdo,ou=svn,dc=osgeo,dc=org
   objectClass: groupOfNames
   cn: fdo
   member: uid=jsmith,ou=people,dc=osgeo,dc=org
   member: uid=jbrown,ou=people,dc=osgeo,dc=org

   dn: cn=gdal,ou=svn,dc=osgeo,dc=org
   cn: gdal
   objectClass: groupOfNames
   objectClass: top
   member: uid=jbrown,ou=people,dc=osgeo,dc=org
   member: uid=jsmith,ou=people,dc=osgeo,dc=org

   dn: cn=mapbender,ou=svn,dc=osgeo,dc=org
   objectClass: groupOfNames
   cn: mapbender
   member: uid=jsmith,ou=people,dc=osgeo,dc=org

   dn: cn=mapguide,ou=svn,dc=osgeo,dc=org
   objectClass: groupOfNames
   cn: mapguide
   member: uid=jbrown,ou=people,dc=osgeo,dc=org

LDAP Clients

Web interface

The LDAP web admin tools were initially written by Frank Warmerdam and subsequently improved by Sandro Santilli. They are written in python and can currently be found in /usr/lib/cgi-bin on the "web vm" (ie. www.osgeo.org). From may 12, 2016, cgi-bin scripts are managed with a local git repository (/usr/lib/cgi-bin/.git). A clone of the git repository is published as a private repository (you will get a 404 unless you are part of the SAC team) on the SAC:Gitea service.

The scripts read the LDAP manager password from a credentials file that will need to be updated anytime the master LDAP manager password is changed.

Some public notes on OSGeo userids available at:

 http://www.osgeo.org/osgeo_userid

User registration

The main entry point for OSGeo users is the registration form:

https://id.osgeo.org/ldap/create

NOTE: as of June 2016 the public user registration form may require entering a "mantra" (a pseudo-secret passphrase) - already registered trusted users can find out what the mantra is and how to share on https://git.osgeo.org/gitea/sac/userid-mantra/wiki (requires login and access grant, otherwise the page will appear as 404).

User edit

To edit an individual userid use ldap_user_edit.py. If you add ?userid=osgeo_userid you can edit someone elses ldap entry as long as you are in the admins group.

 https://www.osgeo.org/cgi-bin/auth/ldap_edit_user.py
 https://www.osgeo.org/cgi-bin/auth/ldap_edit_user.py?userid=osgeotest123

Password reset

Users can request a password reset using this form:

 https://www.osgeo.org/cgi-bin/ldap_password_reset.py

Users lookup

Administrators can login to this special ldap search tool, and will see email address, and will have a link to edit the LDAP entries. You need to be in the cn=admin,ou=projects listing.

 https://www.osgeo.org/cgi-bin/auth/ldap_web_search.py

Groups management

SVN and other groups can be administered with the group editor. You need to either be in the group being viewed/modified or in the cn=admin,ou=projects group in order to edit a group.

Edit GDAL commit list:

 https://www.osgeo.org/cgi-bin/auth/ldap_group.py?group=gdal

Edit Admins list:

 https://www.osgeo.org/cgi-bin/auth/ldap_group.py?group=admin&ou=projects

Shell group management

To edit the list of people who have shell access to the various projects servers, including the download server use the following url. You have to be in the group already, or in the Admins group in order to add and remove people. Adding someone will add the required posixAccount and related attributes to the users LDAP entry.

 https://www.osgeo.org/cgi-bin/auth/ldap_shell.py

The ldap_shell.py script can also operate on other groups used for shell access using the group attribute. Currently the only other group is the sac group used for shell access on the core services VMs at OSU OSL.

 https://www.osgeo.org/cgi-bin/auth/ldap_shell.py?group=sac

Command line interface

The commandline interface can be used by any of the OSGeo machines but not from outside the network. The tools are from the ldap-utils debian package.

All ``ldap-utils`` commands will use systemwide or user-specific files for default configuration so things like LDAP Base (-b dc=osgeo,dc=org) and LDAP URI (-H ldaps://ldap.osgeo.org) need not be specified on each commandline from properly configured machines (grep URI /etc/ldap/ldap.conf; grep BASE /etc/ldap/ldap.conf).

Editing the LDAP database

Editing LDAP database requires an admin password. The -W switch asks for a password prompt (known by SAC:Primary Administrators).

Loading an ldif file into an ldap directory:

  $ ldapadd -a -W -x -D "cn=Manager,dc=osgeo,dc=org" -f fileName.ldif

Deleting an account (by uid) from the database through "ldapdelete":

  $ uid="account-to-be-deleted" ldapdelete -W -D cn=Manager,dc=osgeo,dc=org -x "uid=${uid},ou=People,dc=osgeo,dc=org"

Deleting an account (by uid) from the database through an ad-hoc script from the "www.osgeo.org" machine:

  $ /osgeo/tools/ldap/ldap_delete_user "account-to-be-deleted"

Resetting a user password:

  $ uid="account-to-be-reset" ldappasswd -S -W -D cn=Manager,dc=osgeo,dc=org -x "uid=${uid},ou=People,dc=osgeo,dc=org"
  # Or from the "www.osgeo.org" machine, run:
  $ /osgeo/tools/ldap/ldap_reset_user_password "account-to-be-reset"
  # A new random password will be sent to the user. Asks for confirmation.

Querying the LDAP database

The ldapsearch command is used to query a LDAP database.

This command seems to dump the whole LDAP database. Use with care, but sometime it's the easiest way to search (using grep):

 $ ldapsearch -x

Refine your search based on the LDAP structure listed above.

Example: list all SVN groups (override BASE to limit the ou to svn, then search for objects with the right objectClass).

 $ ldapsearch -s one -b ou=svn,dc=osgeo,dc=org -x "objectClass=groupOfNames" | grep ^cn

Example: list all entries created after April 1st 2016:

 $ ldapsearch -x "createTimestamp>=20160401100000Z"

The fields to be shown in the output can be specified as additional parameters, like:

 $ ldapsearch -x "uid=strk" createtimestamp modifytimestamp

Find the email addresses of all members in the GRASS GIS core group:

 $ ldapsearch -x '(|'`ldapsearch -x 'cn=grass' | grep ^member | sed 's/.* uid=\([^,]*\),.*/(uid=\1)/' | tr -d '\n'`')' | grep ^mail | sed 's/^mail: //'

Find the email addresses of all members in the GRASS GIS core group and store as CSV file (ID, name, email):

 $ ldapsearch -x '(|'`ldapsearch -x 'cn=grass' | grep ^member | sed 's/.* uid=\([^,]*\),.*/(uid=\1)/' | tr -d '\n'`')' | \
              grep '^u: /\n|/'| sed 's/^cn: //' | sed 's/^sn: //' | sed 's/^mail: //' | sed 's/^cn:: //' | sed 's/^sn:: //' \
              | tr '\n' ',' | tr '|' '\n' | sed 's+,,$++g'

If you are on a server that is whitelisted to query osgeo, but the ldap.conf is not setup, you migh need to explicitly specify the host like so

 $ ldapsearch -x -b "dc=osgeo,dc=org" uid=robe -H ldaps://ldap.osgeo.org 

For more complex queries, see http://www.ldapexplorer.com/en/manual/109010000-ldap-filter-syntax.htm

Monitoring

Web-based users creation and editing can be monitored looking at the '/var/log/apache2/www_access.log' files on 'www.osgeo.org'.

A cronjob on TracsvnVM is setup to run hourly ('/etc/cron.hourly/check_excessive_new_ldap_users') and report to the SAC mailing list if more than a given max users are created in that timespam (check the script for details). The scripts to generate the reports are again on 'trac.osgeo.org' machine under '/osgeo/tools/ldap', where a git repository exists.

Troubleshooting

• "sudo" unavailable to LDAP-authenticated users on Debian7. See:

  https://bugs.launchpad.net/ubuntu/+source/gnutls26/+bug/926350 and

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=579647

  • Short form: "libgnutls" in Debian7 is linked against "libgcrypt" which refuses to work in setuid-binaries - like "sudo".
  • Solution: Rebuild "libgnutls" using "libnettle" instead of "libgcrypt":
    • aptitude install libhogweed2 libnettle4 nettle-dev libp11-kit-dev
    • apt-get remove libgnutls-dev
    • apt-get source gnutls26
    • # remove --with-libgcrypt from the debian/rules file
    • # build using this command:
    • debuild -i -uc -us -b
  • Functional GnuTLS packages available on "secure" in /home/martin/GnuTLS.Deb/

• "sudo" unavailable to LDAP-authenticated users on Debian6 with backports. See:

  http://lists.osgeo.org/pipermail/sac/2012-October/004120.html

  • Solution:

<hostname>:~# cat /etc/apt/preferences.d/sudo.pref 
Package: sudo
Pin: version 1.7.4*
Pin-Priority: 1000