SAC:LDAP

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OSGeo endevours to offer a "single signon" for OSGeo services. User help is available in Osgeo Userid Help.

It is currently used for Subversion, Trac, Drupal, QGIS services (hub.qgis.org and plugins.qgis.org), www.osgeo.org, Gitea, Nextcloud, Matrix-Synapse 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, 

$ service slapd [start|stop|restart]

We have moved to OLC:

http://www.zytrax.com/books/ldap/ch6/slapd-config.html#intro

So config file is in: 

/etc/ldap/slapd.d/cn-config # should be modified with ldapmodify


IP access filter is set by via OSGeo7 ufw firewall: refer to OSGeo7 host for details

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 "old-web" container on OSGeo7 (ie. id.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/edit (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://id.osgeo.org/ldap/edit
 https://id.osgeo.org/ldap/edit?userid=osgeotest123

Password reset

Users can request a password reset using this form: 

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

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://id.osgeo.org/ldap/admin/search

There is also a non-admin version of the search, but will not show email nor links to edit: 

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

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://id.osgeo.org/ldap/group?group=gdal

Edit Admins list: 

 https://id.osgeo.org/ldap/group?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://id.osgeo.org/ldap/shell

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://id.osgeo.org/ldap/shell?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 users and groups

Editing LDAP database requires an admin password or root access to secure container. 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.

Editing the LDAP database config

Increasing default page limit - 

$ ssh root@osgeo7-secure
$ ldapmodify -H ldapi:/// -Y EXTERNAL -f modify_max_page_limit.ldif
$ systemctl restart slapd

Where modify_max_page_limit.ldif looks something like 

  dn: olcDatabase={-1}frontend,cn=config
  changetype: modify
  replace: olcSizeLimit
  olcSizeLimit: 500

Querying the LDAP database

The ldapsearch command is used to query a LDAP database.

This command dumps the first 500 entries of the ldap database. Note that secure-dev on osgeo4 has limit set to 40000 for easier pull by admins. refer to modify section for instructions how to set the limits. 

 $ 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"

Example: list all entries created in 2017: 

 $ ldapsearch -x '(&(createTimestamp>=20170101000000Z)(!(createTimestamp>=20180101000000Z)))'

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

If you get an error you can debug source with: 


 $ ldapsearch -x "uid=robe" -b "dc=osgeo,dc=org"  -H ldaps://ldap.osgeo.org -d 1

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