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diff --git a/README.LDAP b/README.LDAP new file mode 100644 index 0000000..4680d43 --- /dev/null +++ b/README.LDAP @@ -0,0 +1,205 @@ +This file explains how to build the optional LDAP functionality of SUDO to +store /etc/sudoers information. This feature is distinct from LDAP passwords. + +For general sudo LDAP configuration details, see the sudoers.ldap manual that +comes with the sudo distribution. A pre-formatted version of the manual may +be found in the sudoers.ldap.cat file. + +The sudo binary compiled with LDAP support should be totally backward +compatible and be syntactically and source code equivalent to its +non LDAP-enabled build. + +LDAP philosophy +=============== +As times change and servers become cheap, an enterprise can easily have 500+ +UNIX servers. Using LDAP to synchronize Users, Groups, Hosts, Mounts, and +others across an enterprise can greatly reduce the administrative overhead. + +In the past, sudo has used a single local configuration file, /etc/sudoers. +While the same sudoers file can be shared among machines, no built-in +mechanism exists to distribute it. Some have attempted to workaround this +by synchronizing changes via CVS/RSYNC/RDIST/RCP/SCP and even NFS. + +By using LDAP for sudoers we gain a centrally administered, globally +available configuration source for sudo. + +For information on OpenLDAP, please see http://www.openldap.org/. + +Definitions +=========== +Many times the word 'Directory' is used in the document to refer to the LDAP +server, structure and contents. + +Many times 'options' are used in this document to refer to sudoer 'defaults'. +They are one and the same. + +Build instructions +================== +The simplest way to build sudo with LDAP support is to include the +'--with-ldap' option. + + $ ./configure --with-ldap + +If your ldap libraries and headers are in a non-standard place, you will need +to specify them at configure time. E.g. + + $ ./configure --with-ldap=/usr/local/ldapsdk + +Sudo is developed using OpenLDAP but Netscape-based LDAP libraries +(such as those present in Solaris) are also known to work. + +Your mileage may vary. Please let the sudo workers mailing list +<sudo-workers@sudo.ws> know if special configuration was required +to build an LDAP-enabled sudo so we can improve sudo. + +Schema Changes +============== +You must add the appropriate schema to your LDAP server before it +can store sudoers content. + +For OpenLDAP, there are two options, depending on how slapd is configured. + +The first option is to copy the file schema.OpenLDAP to the schema +directory (e.g. /etc/openldap/schema). You must then edit your +slapd.conf and add an include line the new schema, e.g. + + # Sudo LDAP schema + include /etc/openldap/schema/sudo.schema + +In order for sudoRole LDAP queries to be efficient, the server must index +the attribute 'sudoUser', e.g. + + # Indices to maintain + index sudoUser eq + +After making the changes to slapd.conf, restart slapd. + +The second option is only for OpenLDAP 2.3 and higher where slapd.conf +has been configured to use on-line configuration. If your slapd.conf +file includes the line: + + database config + +it should be possible to use the schema.olcSudo file. + +You can apply schema.olcSudo using the ldapadd utility or another +suitable LDAP browser. For example: + + # ldapadd -f schema.olcSudo -H ldap://ldapserver -W -x \ + -D cn=Manager,dc=example,dc=com + +There is no need to restart slapd when updating on-line configuration. + +For Netscape-derived LDAP servers such as SunONE, iPlanet or Fedora Directory, +copy the schema.iPlanet file to the schema directory with the name 99sudo.ldif. + +On Solaris, schemas are stored in /var/Sun/mps/slapd-`hostname`/config/schema/. +For Fedora Directory Server, they are stored in /etc/dirsrv/schema/. + +After copying the schema file to the appropriate directory, restart +the LDAP server. + +Finally, using an LDAP browser/editor, enable indexing by editing the +client profile to provide a Service Search Descriptor (SSD) for sudoers, +replacing example.com with your domain: + + serviceSearchDescriptor: sudoers: ou=sudoers,dc=example,dc=com + +If using an Active Directory server, copy schema.ActiveDirectory +to your Windows domain controller and run the following command: + + ldifde -i -f schema.ActiveDirectory -c dc=X dc=example,dc=com + +Importing /etc/sudoers into LDAP +================================ +Importing sudoers is a two-step process. + +Step 1: +Ask your LDAP Administrator where to create the ou=SUDOers container. + +For instance, if using OpenLDAP: + + dn: ou=SUDOers,dc=example,dc=com + objectClass: top + objectClass: organizationalUnit + ou: SUDOers + +(An example location is shown below). Then use the cvtsudoers utility to +convert your sudoers file into LDIF format. + + # SUDOERS_BASE=ou=SUDOers,dc=example,dc=com + # export SUDOERS_BASE + # cvtsudoers -f ldif -o /tmp/sudoers.ldif /etc/sudoers + +Step 2: +Import into your directory server. The following example is for +OpenLDAP. If you are using another directory, provide the LDIF +file to your LDAP Administrator. + + # ldapadd -f /tmp/sudoers.ldif -H ldap://ldapserver \ + -D cn=Manager,dc=example,dc=com -W -x + +Step 3: +Verify the sudoers LDAP data: + + # ldapsearch -b "$SUDOERS_BASE" -D cn=Manager,dc=example,dc=com -W -x + +Managing LDAP entries +===================== +Doing a one-time bulk load of your ldap entries is fine. However what if you +need to make minor changes on a daily basis? It doesn't make sense to delete +and re-add objects. (You can, but this is tedious). + +I recommend using any of the following LDAP browsers to administer your SUDOers. + * GQ - The gentleman's LDAP client - Open Source - I use this a lot on Linux + and since it is Schema aware, I don't need to create a sudoRole template. + http://sourceforge.net/projects/gqclient/ + + * phpQLAdmin - Open Source - phpQLAdmin is an administration tool, + originally for QmailLDAP, that supports editing sudoRole objects + in version 2.3.2 and higher. + http://phpqladmin.com/ + + * LDAP Browser/Editor - by Jarek Gawor - I use this a lot on Windows + and Solaris. It runs anywhere in a Java Virtual Machine including + web pages. You have to make a template from an existing sudoRole entry. + http://www.iit.edu/~gawojar/ldap + http://www.mcs.anl.gov/~gawor/ldap + http://ldapmanager.com + + * Apache Directory Studio - Open Source - an Eclipse-based LDAP + development platform. Includes an LDAP browser, and LDIF editor, + a schema editor and more. + http://directory.apache.org/studio + + There are dozens of others, some Open Source, some free, some not. + +Configure your /etc/ldap.conf and /etc/nsswitch.conf +==================================================== +The /etc/ldap.conf file is meant to be shared between sudo, pam_ldap, nss_ldap +and other ldap applications and modules. IBM Secureway unfortunately uses +the same file name but has a different syntax. If you need to change where +this file is stored, re-run configure with the --with-ldap-conf-file=PATH +option. + +See the "Configuring ldap.conf" section in the sudoers.ldap manual +for a list of supported ldap.conf parameters and an example ldap.conf + +Make sure you sudoers_base matches the location you specified when you +imported the sudoers ldif data. + +After configuring /etc/ldap.conf, you must add a line in /etc/nsswitch.conf +to tell sudo to look in LDAP for sudoers. See the "Configuring nsswitch.conf" +section in the sudoers.ldap manual for details. Note that sudo will use +/etc/nsswitch.conf even if the underlying operating system does not support it. +To disable nsswitch support, run configure with the --with-nsswitch=no option. +This will cause sudo to consult LDAP first and /etc/sudoers second, unless the +ignore_sudoers_file flag is set in the global LDAP options. + +Debugging your LDAP configuration +================================= +Enable debugging if you believe sudo is not parsing LDAP the way you think it +should. Setting the 'sudoers_debug' parameter to a value of 1 shows moderate +debugging. A value of 2 shows the results of the matches themselves. Make +sure to set the value back to zero so that other users don't get confused by +the debugging messages. |