Provided by: sudo-ldap_1.7.2p1-1ubuntu5_i386 bug

NAME

       sudoers.ldap - sudo LDAP configuration

DESCRIPTION

       In addition to the standard sudoers file, sudo may be configured via
       LAP.  This can be especially useful for synchronizing sudoers in a
       large, distributed environment.

       Using LDAP for sudoers has several benefits:

       ·   sudo no longer needs to read sudoers in its entirety.  When LDAP is
           used, there are only two or three LDAP queries per invocation.
           This makes it especially fast and particularly usable in LDAP
           environments.

       ·   sudo no longer exits if there is a typo in sudoers.  It is not
           possible to load LDAP data into the server that does not conform to
           the sudoers schema, so proper syntax is guaranteed.  It is still
           possible to have typos in a user or host name, but this will not
           prevent sudo from running.

       ·   It is possible to specify per-entry options that override the
           global default options.  /etc/sudoers only supports default options
           and limited options associated with user/host/commands/aliases.
           The syntax is complicated and can be difficult for users to
           understand.  Placing the options directly in the entry is more
           natural.

       ·   The visudo program is no longer needed.  visudo provides locking
           and syntax checking of 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, there is no need for a
           specialized tool to check syntax.

       Another major difference between LDAP and file-based sudoers is that in
       LDAP, sudo-specific Aliases are not supported.

       For the most part, there is really no need for sudo-specific Aliases.
       Unix groups or user netgroups can be used in place of User_Aliases and
       RunasAliases.  Host netgroups can be used in place of HostAliases.
       Since Unix groups and netgroups can also be stored in LDAP there is no
       real need for sudo-specific aliases.

       Cmnd_Aliases are not really required either since it is possible to
       have multiple users listed in a sudoRole.  Instead of defining a
       Cmnd_Alias that is referenced by multiple users, one can create a
       sudoRole that contains the commands and assign multiple users to it.

       SUDOers LDAP container

       The sudoers configuration is contained in the ou=SUDOers LDAP
       container.

       Sudo first looks for the cn=default entry in the SUDOers container.  If
       found, the multi-valued sudoOption attribute is parsed in the same
       manner as a global Defaults line in /etc/sudoers.  In the following
       example, the SSH_AUTH_SOCK variable will be preserved in the
       environment for all users.

           dn: cn=defaults,ou=SUDOers,dc=example,dc=com
           objectClass: top
           objectClass: sudoRole
           cn: defaults
           description: Default sudoOption's go here
           sudoOption: env_keep+=SSH_AUTH_SOCK

       The equivalent of a sudoer in LDAP is a sudoRole.  It consists of the
       following components:

       sudoUser
           A user name, uid (prefixed with '#'), Unix group (prefixed with a
           '%') or user netgroup (prefixed with a '+').

       sudoHost
           A host name, IP address, IP network, or host netgroup (prefixed
           with a '+').  The special value ALL will match any host.

       sudoCommand
           A Unix command with optional command line arguments, potentially
           including globbing characters (aka wild cards).  The special value
           ALL will match any command.  If a command is prefixed with an
           exclamation point '!', the user will be prohibited from running
           that command.

       sudoOption
           Identical in function to the global options described above, but
           specific to the sudoRole in which it resides.

       sudoRunAsUser
           A user name or uid (prefixed with '#') that commands may be run as
           or a Unix group (prefixed with a '%') or user netgroup (prefixed
           with a '+') that contains a list of users that commands may be run
           as.  The special value ALL will match any user.

       sudoRunAsGroup
           A Unix group or gid (prefixed with '#') that commands may be run
           as.  The special value ALL will match any group.

       Each component listed above should contain a single value, but there
       may be multiple instances of each component type.  A sudoRole must
       contain at least one sudoUser, sudoHost and sudoCommand.

       The following example allows users in group wheel to run any command on
       any host via sudo:

           dn: cn=%wheel,ou=SUDOers,dc=example,dc=com
           objectClass: top
           objectClass: sudoRole
           cn: %wheel
           sudoUser: %wheel
           sudoHost: ALL
           sudoCommand: ALL

       Anatomy of LDAP sudoers lookup

       When looking up a sudoer using LDAP there are only two or three LDAP
       queries per invocation.  The first query is to parse the global
       options.  The second is to match against the user’s name and the groups
       that the user belongs to.  (The special ALL tag is matched in this
       query too.)  If no match is returned for the user’s name and groups, a
       third query returns all entries containing user netgroups and checks to
       see if the user belongs to any of them.

       Differences between LDAP and non-LDAP sudoers

       There are some subtle differences in the way sudoers is handled once in
       LDAP.  Probably the biggest is that according to the RFC, LDAP ordering
       is arbitrary and you cannot expect that Attributes and Entries are
       returned in any specific 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, the following attributes do not
       behave the way one might expect.

           # 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

       Sudoers Schema

       In order to use sudo’s LDAP support, the sudo schema must be installed
       on your LDAP server.  In addition, be sure to index the ’sudoUser’
       attribute.

       Three versions of the schema: one for OpenLDAP servers
       (schema.OpenLDAP), one for Netscape-derived servers (schema.iPlanet),
       and one for Microsoft Active Directory (schema.ActiveDirectory) may be
       found in the sudo distribution.

       The schema for sudo in OpenLDAP form is included in the EXAMPLES
       section.

       Configuring ldap.conf

       Sudo reads the /etc/sudo-ldap.conf file for LDAP-specific
       configuration.  Typically, this file is shared amongst different LDAP-
       aware clients.  As such, most of the settings are not sudo-specific.
       Note that sudo parses /etc/sudo-ldap.conf itself and may support
       options that differ from those described in the ldap.conf(5) manual.

       Also note that on systems using the OpenLDAP libraries, default values
       specified in /etc/openldap/ldap.conf or the user’s .ldaprc files are
       not used.

       Only those options explicitly listed in /etc/sudo-ldap.conf that are
       supported by sudo are honored.  Configuration options are listed below
       in upper case but are parsed in a case-independent manner.

       URI ldap[s]://[hostname[:port]] ...
           Specifies a whitespace-delimited list of one or more URIs
           describing the LDAP server(s) to connect to.  The protocol may be
           either ldap or ldaps, the latter being for servers that support TLS
           (SSL) encryption.  If no port is specified, the default is port 389
           for ldap:// or port 636 for ldaps://.  If no hostname is specified,
           sudo will connect to localhost.  Only systems using the OpenSSL
           libraries support the mixing of ldap:// and ldaps:// URIs.  The
           Netscape-derived libraries used on most commercial versions of Unix
           are only capable of supporting one or the other.

       HOST name[:port] ...
           If no URI is specified, the HOST parameter specifies a whitespace-
           delimited list of LDAP servers to connect to.  Each host may
           include an optional port separated by a colon (’:’).  The HOST
           parameter is deprecated in favor of the URI specification and is
           included for backwards compatibility.

       PORT port_number
           If no URI is specified, the PORT parameter specifies the default
           port to connect to on the LDAP server if a HOST parameter does not
           specify the port itself.  If no PORT parameter is used, the default
           is port 389 for LDAP and port 636 for LDAP over TLS (SSL).  The
           PORT parameter is deprecated in favor of the URI specification and
           is included for backwards compatibility.

       BIND_TIMELIMIT seconds
           The BIND_TIMELIMIT parameter specifies the amount of time, in
           seconds, to wait while trying to connect to an LDAP server.  If
           multiple URIs or HOSTs are specified, this is the amount of time to
           wait before trying the next one in the list.

       TIMELIMIT seconds
           The TIMELIMIT parameter specifies the amount of time, in seconds,
           to wait for a response to an LDAP query.

       SUDOERS_BASE base
           The base DN to use when performing sudo LDAP queries.  Typically
           this is of the form ou=SUDOers,dc=example,dc=com for the domain
           example.com.

       SUDOERS_DEBUG debug_level
           This sets the debug level for sudo LDAP queries.  Debugging
           information is printed to the standard error.  A value of 1 results
           in a moderate amount of debugging information.  A value of 2 shows
           the results of the matches themselves.  This parameter should not
           be set in a production environment as the extra information is
           likely to confuse users.

       BINDDN DN
           The BINDDN parameter specifies the identity, in the form of a
           Distinguished Name (DN), to use when performing LDAP operations.
           If not specified, LDAP operations are performed with an anonymous
           identity.  By default, most LDAP servers will allow anonymous
           access.

       BINDPW secret
           The BINDPW parameter specifies the password to use when performing
           LDAP operations.  This is typically used in conjunction with the
           BINDDN parameter.

       ROOTBINDDN DN
           The ROOTBINDDN parameter specifies the identity, in the form of a
           Distinguished Name (DN), to use when performing privileged LDAP
           operations, such as sudoers queries.  The password corresponding to
           the identity should be stored in /etc/ldap.secret.  If not
           specified, the BINDDN identity is used (if any).

       LDAP_VERSION number
           The version of the LDAP protocol to use when connecting to the
           server.  The default value is protocol version 3.

       SSL on/true/yes/off/false/no
           If the SSL parameter is set to on, true or yes, TLS (SSL)
           encryption is always used when communicating with the LDAP server.
           Typically, this involves connecting to the server on port 636
           (ldaps).

       SSL start_tls
           If the SSL parameter is set to start_tls, the LDAP server
           connection is initiated normally and TLS encryption is begun before
           the bind credentials are sent.  This has the advantage of not
           requiring a dedicated port for encrypted communications.  This
           parameter is only supported by LDAP servers that honor the
           start_tls extension, such as the OpenLDAP server.

       TLS_CHECKPEER on/true/yes/off/false/no
           If enabled, TLS_CHECKPEER will cause the LDAP server’s TLS
           certificated to be verified.  If the server’s TLS certificate
           cannot be verified (usually because it is signed by an unknown
           certificate authority), sudo will be unable to connect to it.  If
           TLS_CHECKPEER is disabled, no check is made.

       TLS_CACERTFILE file name
           The path to a certificate authority bundle which contains the
           certificates for all the Certificate Authorities the client knows
           to be valid, e.g. /etc/ssl/ca-bundle.pem.  This option is only
           supported by the OpenLDAP libraries.

       TLS_CACERTDIR directory
           Similar to TLS_CACERTFILE but instead of a file, it is a directory
           containing individual Certificate Authority certificates, e.g.
           /etc/ssl/certs.  The directory specified by TLS_CACERTDIR is
           checked after TLS_CACERTFILE.  This option is only supported by the
           OpenLDAP libraries.

       TLS_CERT file name
           The path to a file containing the client certificate which can be
           used to authenticate the client to the LDAP server.  The
           certificate type depends on the LDAP libraries used.

           OpenLDAP:
               tls_cert /etc/ssl/client_cert.pem

           Netscape-derived:
               tls_cert /var/ldap/cert7.db

           When using Netscape-derived libraries, this file may also contain
           Certificate Authority certificates.

       TLS_KEY file name
           The path to a file containing the private key which matches the
           certificate specified by TLS_CERT.  The private key must not be
           password-protected.  The key type depends on the LDAP libraries
           used.

           OpenLDAP:
               tls_key /etc/ssl/client_key.pem

           Netscape-derived:
               tls_key /var/ldap/key3.db

       TLS_RANDFILE file name
           The TLS_RANDFILE parameter specifies the path to an entropy source
           for systems that lack a random device.  It is generally used in
           conjunction with prngd or egd.  This option is only supported by
           the OpenLDAP libraries.

       TLS_CIPHERS cipher list
           The TLS_CIPHERS parameter allows the administer to restrict which
           encryption algorithms may be used for TLS (SSL) connections.  See
           the OpenSSL manual for a list of valid ciphers.  This option is
           only supported by the OpenLDAP libraries.

       USE_SASL on/true/yes/off/false/no
           Enable USE_SASL for LDAP servers that support SASL authentication.

       SASL_AUTH_ID identity
           The SASL user name to use when connecting to the LDAP server.  By
           default, sudo will use an anonymous connection.

       ROOTUSE_SASL on/true/yes/off/false/no
           Enable ROOTUSE_SASL to enable SASL authentication when connecting
           to an LDAP server from a privileged process, such as sudo.

       ROOTSASL_AUTH_ID identity
           The SASL user name to use when ROOTUSE_SASL is enabled.

       SASL_SECPROPS none/properties
           SASL security properties or none for no properties.  See the SASL
           programmer’s manual for details.

       KRB5_CCNAME file name
           The path to the Kerberos 5 credential cache to use when
           authenticating with the remote server.

       See the ldap.conf entry in the EXAMPLES section.

       Configuring nsswitch.conf

       Unless it is disabled at build time, sudo consults the Name Service
       Switch file, /etc/nsswitch.conf, to specify the sudoers search order.
       Sudo looks for a line beginning with sudoers: and uses this to
       determine the search order.  Note that sudo does not stop searching
       after the first match and later matches take precedence over earlier
       ones.

       The following sources are recognized:

           files       read sudoers from F</etc/sudoers>
           ldap        read sudoers from LDAP

       In addition, the entry [NOTFOUND=return] will short-circuit the search
       if the user was not found in the preceding source.

       To consult LDAP first followed by the local sudoers file (if it
       exists), use:

           sudoers: ldap files

       The local sudoers file can be ignored completely by using:

           sudoers: ldap

       If the /etc/nsswitch.conf file is not present or there is no sudoers
       line, the following default is assumed:

           sudoers: files

       Note that /etc/nsswitch.conf is supported even when the underlying
       operating system does not use an nsswitch.conf file.

       Configuring netsvc.conf

       On AIX systems, the /etc/netsvc.conf file is consulted instead of
       /etc/nsswitch.conf.  sudo simply treats netsvc.conf as a variant of
       nsswitch.conf; information in the previous section unrelated to the
       file format itself still applies.

       To consult LDAP first followed by the local sudoers file (if it
       exists), use:

           sudoers = ldap, files

       The local sudoers file can be ignored completely by using:

           sudoers = ldap

       To treat LDAP as authoratative and only use the local sudoers file if
       the user is not present in LDAP, use:

           sudoers = ldap = auth, files

       Note that in the above example, the auth qualfier only affects user
       lookups; both LDAP and sudoers will be queried for Defaults entries.

       If the /etc/netsvc.conf file is not present or there is no sudoers
       line, the following default is assumed:

           sudoers = files

FILES

       /etc/sudo-ldap.conf     LDAP configuration file

       /etc/nsswitch.conf      determines sudoers source order

       /etc/netsvc.conf        determines sudoers source order on AIX

EXAMPLES

       Example 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.secret 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, tls_cert and tls_key may specify either
         # a directory, in which case the files in the directory must have the
         # default names (e.g. cert8.db and key4.db), or the path to the cert
         # and key files themselves.  However, a bug in version 5.0 of the LDAP
         # SDK will prevent specific file names from working.  For this reason
         # it is suggested that tls_cert and tls_key be set to a directory,
         # not a file name.
         #
         # The certificate database 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
         #tls_key /var/ldap
         #
         # If using SASL authentication for LDAP (OpenSSL)
         # use_sasl yes
         # sasl_auth_id <SASL username>
         # rootuse_sasl yes
         # rootsasl_auth_id <SASL username for root access>
         # sasl_secprops none
         # krb5_ccname /etc/.ldapcache

       Sudo schema for OpenLDAP

       The following schema is in OpenLDAP format.  Simply copy it to the
       schema directory (e.g. /etc/openldap/schema), add the proper include
       line in slapd.conf and restart slapd.

        attributetype ( 1.3.6.1.4.1.15953.9.1.1
           NAME 'sudoUser'
           DESC 'User(s) who may  run sudo'
           EQUALITY caseExactIA5Match
           SUBSTR caseExactIA5SubstringsMatch
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.2
           NAME 'sudoHost'
           DESC 'Host(s) who may run sudo'
           EQUALITY caseExactIA5Match
           SUBSTR caseExactIA5SubstringsMatch
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.3
           NAME 'sudoCommand'
           DESC 'Command(s) to be executed by sudo'
           EQUALITY caseExactIA5Match
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.4
           NAME 'sudoRunAs'
           DESC 'User(s) impersonated by sudo'
           EQUALITY caseExactIA5Match
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.5
           NAME 'sudoOption'
           DESC 'Options(s) followed by sudo'
           EQUALITY caseExactIA5Match
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.6
           NAME 'sudoRunAsUser'
           DESC 'User(s) impersonated by sudo'
           EQUALITY caseExactIA5Match
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        attributetype ( 1.3.6.1.4.1.15953.9.1.7
           NAME 'sudoRunAsGroup'
           DESC 'Group(s) impersonated by sudo'
           EQUALITY caseExactIA5Match
           SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

        objectclass ( 1.3.6.1.4.1.15953.9.2.1 NAME 'sudoRole' SUP top STRUCTURAL
           DESC 'Sudoer Entries'
           MUST ( cn )
           MAY ( sudoUser $ sudoHost $ sudoCommand $ sudoRunAs $ sudoRunAsUser $
                 sudoRunAsGroup $ sudoOption $ description )
           )

SEE ALSO

       ldap.conf(5), sudoers(5)

CAVEATS

       The way that sudoers is parsed differs between Note that there are
       differences in the way that LDAP-based sudoers is parsed compared to
       file-based sudoers.  See the "Differences between LDAP and non-LDAP
       sudoers" section for more information.

BUGS

       If you feel you have found a bug in sudo, please submit a bug report at
       http://www.sudo.ws/sudo/bugs/

SUPPORT

       Limited free support is available via the sudo-users mailing list, see
       http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
       the archives.

DISCLAIMER

       sudo is provided ‘‘AS IS’’ and any express or implied warranties,
       including, but not limited to, the implied warranties of
       merchantability and fitness for a particular purpose are disclaimed.
       See the LICENSE file distributed with sudo or
       http://www.sudo.ws/sudo/license.html for complete details.