-This file explains how to use the optional LDAP functionality of SUDO to
+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.
-Sudo in the past has only used a single local configuration file /etc/sudoers.
-Some have attempted to workaround this by synchronizing changes via
-RCS/CVS/RSYNC/RDIST/RCP/SCP and even NFS. Many have asked for a Hesiod, NIS,
-or LDAP patch for sudo, so here is my attempt at LDAP'izing sudo.
+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/.
Many times 'options' are used in this document to refer to sudoer 'defaults'.
They are one and the same.
-Design Features
-===============
-
- * Sudo no longer needs to read sudoers in its entirety. Parsing of
- /etc/sudoers requires the entire file to be read. The LDAP feature of sudo
- uses two (sometimes three) LDAP queries per invocation. It never reads all
- the sudoer entries in the LDAP store. This makes it especially fast and
- particularly usable in LDAP environments. The first query is to parse
- default options (see below). The second is to match against the username or
- groups a user belongs to. (The special ALL tag is matched in this query
- too.) If no match is made against the username, the third query pulls the
- entries that match against user netgroups to compare back to the user.
-
- * Sudo no longer blows up if there is a typo. Parsing of /etc/sudoers can
- still blow up when sudo is invoked. However when using the LDAP feature of
- sudo, LDAP syntax rules are applied before the data is uploaded into the
- LDAP server, so proper syntax is always guaranteed! One can of course still
- insert a bogus hostname or username, but sudo will not care.
-
- * Options inside of entries now override global default options.
- /etc/sudoers allowed for only default options and limited options associated
- with user/host/command aliases. The syntax can be difficult for the newbie.
- The LDAP feature attempts to simplify this and yet still provide maximum
- flexibility.
-
- Sudo first looks for an entry called 'cn=default' in the SUDOers container.
- If found, the multi-valued sudoOption attribute is parsed the same way the
- global 'Defaults' line in /etc/sudoers is parsed.
-
- If on the second or third query, a response contains a sudoRole which
- matches against the user, host, and command, then the matched object is
- scanned for a additional options to override the top-level defaults. See
- the example LDAP content below for more information.
-
- * Visudo is no longer needed. Visudo provides locking and syntax checking
- against the /etc/sudoers file. Since LDAP updates are atomic, locking is no
- longer necessary. Because syntax is checked when the data is inserted into
- LDAP, the sudoers syntax check becomes unnecessary.
-
- * Aliases are no longer needed. User, Host, and Command Aliases were setup
- to allow simplification and readability of the sudoers files. Since the
- LDAP sudoer entry allows multiple values for each of its attributes and
- since most LDAP browsers are graphical and easy to work with, original
- aliases are no longer needed.
-
- If you want to specify lots of users into an entry or want to have similar
- entries with identical users, then use either groups or user netgroups.
- Thats what groups and netgroups are for and Sudo handles this well.
- Alternately, one can just paste them all into the LDAP record.
-
- If you want to specify lots of hosts into an entry, use netgroups or IP
- address matches (10.2.3.4/255.255.0.0). Thats what netgroups are for and
- Sudo handles this well. Or just past them all into the LDAP record.
-
- If you want to specify lots of commands, use directories or wildcards, or
- just paste them all into LDAP. That's what it's for.
-
- * The /etc/sudoers file can be disabled. Paranoid security administrators
- can now disallow parsing of any local /etc/sudoers file by an LDAP
- sudoOption 'ignore_local_sudoers'. This way all sudoers can be controlled
- and audited in one place because local entries are not allowed.
- In fact, if this option is included in the cn=defaults object of LDAP,
- sudo won't even look for a /etc/sudoers 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.
-
-
Build instructions
==================
-The most simplest way to build sudo with LDAP support is to include the
+The simplest way to build sudo with LDAP support is to include the
'--with-ldap' option.
$ ./configure --with-ldap
$ ./configure --with-ldap=/usr/local/ldapsdk
-Sudo is developed using OpenLDAP. Other LDAP implementations may
-require adding '-lldif' to SUDO_LIBS in the Makefile.
+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 what combinations worked best for your
-OS and LDAP Combinations so we can improve sudo.
-
-More Build Notes:
-HP-UX 11.23 (gcc3) Galen Johnson <Galen.Johnson@sas.com>
- CFLAGS="-D__10_10_compat_code" LDFLAGS="-L/opt/ldapux/lib"
+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
==============
-Add the appropriate schema to your LDAP server so that it may contain
-sudoers content.
+You must add the appropriate schema to your LDAP server before it
+can store sudoers content.
+
+For OpenLDAP, 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.
+
+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.
-For OpenLDAP, simply copy schema.OpenLDAP to the schema directory
-(e.g. /etc/openldap/schema) and 'include' it in your slapd.conf and
-restart slapd. For other LDAP servers, provide this to your LDAP
-Administrator. Make sure to index the attribute 'sudoUser'.
+On Solaris, schemas are stored in /var/Sun/mps/slapd-`hostname`/config/schema/.
+For Fedora Directory Server, they are stored in /etc/dirsrv/schema/.
-For netscape-derived LDAP servers such as SunONE, iPlanet or Fedora
-Directory, use the schema.iPlanet file.
+After copying the schema file to the appropriate directory, restart
+the LDAP server.
-Importing /etc/sudoers to LDAP
-==============================
-Importing is a two step process.
+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.
# ./sudoers2ldif /etc/sudoers > /tmp/sudoers.ldif
Step 2:
-Import into your directory server. If you are using OpenLDAP, do the following
-if you are using another directory, provide the LDIF file to your LDAP
-Administrator. An example is shown below.
+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 ldapserver \
- > -D cn=Manager,dc=example,dc=com -W -x
-
-Example sudoers Entries in LDAP
-===============================
-The equivalent of a sudoer in LDAP is a 'sudoRole'. It contains sudoUser(s),
-sudoHost, sudoCommand and optional sudoOption(s) and sudoRunAs(s).
-
-The following example allows users in group wheel to run any
-command on any host through sudo:
-
-dn: cn=%wheel,ou=SUDOers,dc=example,dc=com
-objectClass: top
-objectClass: sudoRole
-cn: %wheel
-sudoUser: %wheel
-sudoHost: ALL
-sudoCommand: ALL
+ -D cn=Manager,dc=example,dc=com -W -x
Managing LDAP entries
=====================
and since it is Schema aware, I don't need to create a sudoRole template.
http://biot.com/gq/
+ * 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.
There are dozens of others, some Open Source, some free, some not.
-
-Configure your /etc/ldap.conf
-=============================
+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 filename but has a different syntax. If you need to rename where
-this file is stored, re-run configure with the --with-ldap-conf-file=filename
+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.
-Make sure you sudoers_base matches exactly with the location you specified
-when you imported the sudoers. Below is an example /etc/ldap.conf
-
- # Either specify one or more URIs or one or more host:port pairs.
- # If neither is specified sudo will default to localhost, port 389.
- #
- #host ldapserver
- #host ldapserver1 ldapserver2:390
- #
- # Default port if host is specified without one, defaults to 389.
- #port 389
- #
- # URI will override the host and port settings.
- uri ldap://ldapserver
- #uri ldaps://secureldapserver
- #uri ldaps://secureldapserver ldap://ldapserver
- #
- # The amount of time, in seconds, to wait while trying to connect to
- # an LDAP server.
- bind_timelimit 30
- #
- # The amount of time, in seconds, to wait while performing an LDAP query.
- timelimit 30
- #
- # must be set or sudo will ignore LDAP
- sudoers_base ou=SUDOers,dc=example,dc=com
- #
- # verbose sudoers matching from ldap
- #sudoers_debug 2
- #
- # optional proxy credentials
- #binddn <who to search as>
- #bindpw <password>
- #rootbinddn <who to search as, uses /etc/ldap.passwd for bindpw>
- #
- # LDAP protocol version, defaults to 3
- #ldap_version 3
- #
- # Define if you want to use an encrypted LDAP connection.
- # Typically, you must also set the port to 636 (ldaps).
- #ssl on
- #
- # Define if you want to use port 389 and switch to
- # encryption before the bind credentials are sent.
- # Only supported by LDAP servers that support the start_tls
- # extension such as OpenLDAP.
- #ssl start_tls
- #
- # Additional TLS options follow that allow tweaking of the
- # SSL/TLS connection.
- #
- #tls_checkpeer yes # verify server SSL certificate
- #tls_checkpeer no # ignore server SSL certificate
- #
- # If you enable tls_checkpeer, specify either tls_cacertfile
- # or tls_cacertdir. Only supported when using OpenLDAP.
- #
- #tls_cacertfile /etc/certs/trusted_signers.pem
- #tls_cacertdir /etc/certs
- #
- # For systems that don't have /dev/random
- # use this along with PRNGD or EGD.pl to seed the
- # random number pool to generate cryptographic session keys.
- # Only supported when using OpenLDAP.
- #
- #tls_randfile /etc/egd-pool
- #
- # You may restrict which ciphers are used. Consult your SSL
- # documentation for which options go here.
- # Only supported when using OpenLDAP.
- #
- #tls_ciphers <cipher-list>
- #
- # Sudo can provide a client certificate when communicating to
- # the LDAP server.
- # Tips:
- # * Enable both lines at the same time.
- # * Do not password protect the key file.
- # * Ensure the keyfile is only readable by root.
- #
- # For OpenLDAP:
- #tls_cert /etc/certs/client_cert.pem
- #tls_key /etc/certs/client_key.pem
- #
- # For SunONE or iPlanet LDAP, the file specified by tls_cert may
- # contain CA certs and/or the client's cert. If the client's
- # cert is included, tls_key should be specified as well.
- # For backward compatibility, sslpath may be used in place of tls_cert.
- #tls_cert /var/ldap/cert7.db
- #tls_key /var/ldap/key3.db
+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
-it should. 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. This value
-is 'sudoers_debug' in the /etc/ldap.conf.
-
-Parsing Differences between /etc/sudoers and LDAP
-=================================================
-There are some subtle differences in the way sudoers is handled once in LDAP.
-Probably the biggest is that according to the RFC, LDAP's ordering is
-arbitrary and you cannot expect that Attributes & Entries are returned in
-any order. If there are conflicting command rules on an entry, the negative
-takes precedence. This is called paranoid behavior (not necessarily the
-most specific match).
-
-Here is an example:
-
- # /etc/sudoers:
- # Allow all commands except shell
- johnny ALL=(root) ALL,!/bin/sh
- # Always allows all commands because ALL is matched last
- puddles ALL=(root) !/bin/sh,ALL
-
- # LDAP equivalent of Johnny
- # Allows all commands except shell
- dn: cn=role1,ou=Sudoers,dc=my-domain,dc=com
- objectClass: sudoRole
- objectClass: top
- cn: role1
- sudoUser: johnny
- sudoHost: ALL
- sudoCommand: ALL
- sudoCommand: !/bin/sh
-
- # LDAP equivalent of Puddles
- # Notice that even though ALL comes last, it still behaves like
- # role1 since the LDAP code assumes the more paranoid configuration
- dn: cn=role2,ou=Sudoers,dc=my-domain,dc=com
- objectClass: sudoRole
- objectClass: top
- cn: role2
- sudoUser: puddles
- sudoHost: ALL
- sudoCommand: !/bin/sh
- sudoCommand: ALL
-
-Another difference is that negations on the Host, User or Runas are
-currently ignorred. For example, these attributes do not work how
-they first seem.
-
- # does not match all but joe
- # rather, does not match anyone
- sudoUser: !joe
-
- # does not match all but joe
- # rather, matches everyone including Joe
- sudoUser: ALL
- sudoUser: !joe
-
- # does not match all but web01
- # rather, matches all hosts including web01
- sudoHost: ALL
- sudoHost: !web01
+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.
projects / debian / sudo / blobdiff