sudoers.ldap
—
sudo
may be configured via LDAP. 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.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.sudo
-specific Aliases are not supported.
For the most part, there is really no need for
sudo
-specific Aliases. Unix groups,
non-Unix groups (via the group_plugin) or user
netgroups can be used in place of User_Aliases and Runas_Aliases. Host
netgroups can be used in place of Host_Aliases. Since 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.
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
sudoRole
. It
consists of the following attributes:
#
’), Unix group name or ID
(prefixed with ‘%
’ or
‘%#
’ respectively), user netgroup
(prefixed with ‘+
’), or non-Unix
group name or ID (prefixed with ‘%:
’
or ‘%:#
’ respectively). Non-Unix
group support is only available when an appropriate
group_plugin is defined in the global
defaults sudoRole
object.+
’). The special value
ALL
will match any host.!
’, the user will be prohibited
from running that command.
The built-in command “sudoedit
” is
used to permit a user to run sudo
with
the -e
option (or as
sudoedit
). It may take command line
arguments just as a normal command does. Note that
“sudoedit
” is a command built into
sudo
itself and must be specified in
without a leading path.
The special value ALL
will match any command.
If a command name is prefixed with a SHA-2 digest, it will only be allowed
if the digest matches. This may be useful in situations where the user
invoking sudo
has write access to the
command or its parent directory. The following digest formats are
supported: sha224, sha256, sha384 and sha512. The digest name must be
followed by a colon (‘:
’) and then
the actual digest, in either hex or base64 format. For example, given the
following value for sudoCommand:
sha224:0GomF8mNN3wlDt1HD9XldjJ3SNgpFdbjO1+NsQ /bin/ls
sudoRole
in which it resides.#
’) 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.
The sudoRunAsUser
attribute is only available in
sudo
versions 1.7.0 and higher. Older
versions of sudo
use the
sudoRunAs
attribute instead.#
’) that commands may be run as.
The special value ALL
will match any group.
The sudoRunAsGroup
attribute is only available in
sudo
versions 1.7.0 and higher.yyyymmddHHMMSSZ
that can
be used to provide a start date/time for when the
sudoRole
will be valid. If multiple
sudoNotBefore
entries are present, the earliest is
used. Note that timestamps must be in Coordinated Universal Time (UTC),
not the local timezone. The minute and seconds portions are optional, but
some LDAP servers require that they be present (contrary to the RFC).
The sudoNotBefore
attribute is only available in
sudo
versions 1.7.5 and higher and must
be explicitly enabled via the SUDOERS_TIMED
option in /etc/ldap.conf.yyyymmddHHMMSSZ
that
indicates an expiration date/time, after which the
sudoRole
will no longer be valid. If multiple
sudoNotBefore
entries are present, the last one is
used. Note that timestamps must be in Coordinated Universal Time (UTC),
not the local timezone. The minute and seconds portions are optional, but
some LDAP servers require that they be present (contrary to the RFC).
The sudoNotAfter
attribute is only available in
sudo
versions 1.7.5 and higher and must
be explicitly enabled via the SUDOERS_TIMED
option in /etc/ldap.conf.sudoRole
entries retrieved from the LDAP
directory have no inherent order. The sudoOrder
attribute is an integer (or floating point value for LDAP servers that
support it) that is used to sort the matching entries. This allows
LDAP-based sudoers entries to more closely mimic the behavior of the
sudoers file, where the of the entries influences the result. If multiple
entries match, the entry with the highest
sudoOrder
attribute is chosen. This corresponds to
the “last match” behavior of the sudoers file. If the
sudoOrder
attribute is not present, a value of 0
is assumed.
The sudoOrder
attribute is only available in
sudo
versions 1.7.5 and higher.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
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 other non-Unix groups and checks to see
if the user belongs to any of them.
If timed entries are enabled with the SUDOERS_TIMED
configuration directive, the LDAP queries include a sub-filter that limits
retrieval to entries that satisfy the time constraints, if any.
If the NETGROUP_BASE configuration directive is
present (see
Configuring
ldap.conf below), queries are performed to determine the list of netgroups
the user belongs to before the sudoers query. This makes it possible to
include netgroups in the sudoers query string in the same manner as Unix
groups. The third query mentioned above is not performed unless a group
provider plugin is also configured. The actual LDAP queries performed by
sudo
are as follows:
nisNetgroup
records with a
nisNetgroupTriple
containing the user, host and
NIS domain. The query will match nisNetgroupTriple
entries with either the short or long form of the host name or no host
name specified in the tuple. If the NIS domain is set, the query will
match only match entries that include the domain or for which there is no
domain present. If the NIS domain is not set,
a wildcard is used to match any domain name but be aware that the NIS
schema used by some LDAP servers may not support wild cards for
nisNetgroupTriple
.nisNetgroup
records with a
memberNisNetgroup
entry that refers to an
already-matched record.sudo
's execution time.
sudoOrder
attribute, but there is no way to guarantee
the order of attributes within a specific entry. If there are conflicting
command rules in 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
# 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
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 also
included in the EXAMPLES
section.
sudo
-specific. Note that
sudo
parses
/etc/ldap.conf itself and may support
options that differ from those described in the system's
ldap.conf(8) manual. The path to
ldap.conf may be overridden via the
ldap_conf plugin argument in
sudo.conf(5).
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/ldap.conf as being supported by
sudo
are honored. Configuration options are
listed below in upper case but are parsed in a case-independent manner.
The pound sign (‘#
’) is used to indicate a
comment. Both the comment character and any text after it, up to the end of
the line, are ignored. Long lines can be continued with a backslash
(‘\
’) as the last character on the line.
Note that leading white space is removed from the beginning of lines even when
the continuation character is used.
BINDPW base64:dGVzdA==
#
’) and the escaping of special
characters with a backslash (‘\
’) is
not supported.:
’). The
HOST parameter is deprecated in favor of the
URI specification and is included for
backwards compatibility only.ou=netgroup,dc=example,dc=com
for
the domain example.com
. Multiple
NETGROUP_BASE lines may be specified, in
which case they are queried in the order specified.
This option can be used to query a user's netgroups directly via LDAP which
is usually faster than fetching every sudoRole
object containing a sudoUser
that begins with a
‘+
’ prefix. The NIS schema used by
some LDAP servers need a modificaton to support querying the
nisNetgroup
object by its
nisNetgroupTriple
member. OpenLDAP's
slapd requires the following change to the
nisNetgroupTriple
attribute:
attributetype ( 1.3.6.1.1.1.1.14 NAME 'nisNetgroupTriple' DESC 'Netgroup triple' EQUALITY caseIgnoreIA5Match SUBSTR caseIgnoreIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
attribute=value
or
(&(attribute=value)(attribute2=value2))
. The
default search filter is: objectClass=nisNetgroup
.
If ldap_filter is omitted, no search
filter will be used. This option is only when querying netgroups directly
via LDAP.sudo
.sudo
will use an anonymous connection.
This option is only relevant when using SASL authentication.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).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 and Tivoli Directory servers.sudo
LDAP queries. Typically this is of the form
ou=SUDOers,dc=example,dc=com
for the domain
example.com
. Multiple
SUDOERS_BASE lines may be specified, in which
case they are queried in the order specified.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.
The SUDOERS_DEBUG parameter is deprecated and
will be removed in a future release. The same information is now logged
via the sudo
debugging framework using
the “ldap” subsystem at priorities
diag and info
for debug_level values 1 and 2 respectively.
See the sudo.conf(5) manual for details on
how to configure sudo
debugging.sudo
LDAP query.
Typically, this is of the form attribute=value
or
(&(attribute=value)(attribute2=value2))
. The
default search filter is: objectClass=sudoRole
. If
ldap_filter is omitted, no search filter
will be used.sudoNotBefore
and
sudoNotAfter
attributes that implement
time-dependent sudoers entries.tls_cert
/etc/ssl/client_cert.pem
tls_cert
/var/ldap/cert7.db
sudo
will be unable to
connect to it. If TLS_CHECKPEER is disabled,
no check is made. Note that disabling the check creates an opportunity for
man-in-the-middle attacks since the server's identity will not be
authenticated. If possible, the CA's certificate should be installed
locally so it can be verified. This option is not supported by the Tivoli
Directory Server LDAP libraries.tls_key
/etc/ssl/client_key.pem
tls_key
/var/ldap/key3.db
tls_key
/usr/ldap/ldapkey.kdb
TLS_KEYPW base64:dGVzdA==
#
’) and the escaping of special
characters with a backslash (‘\
’) is
not supported. If this option is used,
/etc/ldap.conf must not be
world-readable to avoid exposing the password. Alternately, a
stash file can be used to store the password
in encrypted form (see below).
If no TLS_KEYPW is specified, a
stash file will be used if it exists. The
stash file must have the same path as the
file specified by TLS_KEY, but use a
.sth
file extension instead of
.kdb
, e.g. ldapkey.sth
.
The default ldapkey.kdb
that ships with Tivoli
Directory Server is encrypted with the password
ssl_password
. The
gsk8capicmd utility can be used to manage the
key database and create a stash file. This
option is only supported by the Tivoli LDAP libraries.ldap://
or
port 636 for ldaps://
. If no
hostname is specified,
sudo
will connect to
localhost. Multiple
URI lines are treated identically to a
URI line containing multiple entries. Only
systems using the OpenSSL libraries support the mixing of
ldap://
and ldaps://
URIs.
Both the Netscape-derived and Tivoli LDAP libraries used on most
commercial versions of Unix are only capable of supporting one or the
other.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:
[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
sudoers: ldap
sudoers: files
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
sudoers = ldap
sudoers = ldap = auth, files
auth
qualifier 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
sudo
has been built with
SSSD support, it is possible to use SSSD to cache LDAP
sudoers rules. To use SSSD as the
sudoers source, you should use
sssd
instead of ldap
for the
sudoers entry in /etc/nsswitch.conf. Note
that the /etc/ldap.conf file is not used by
the SSSD sudo
back end. Please see
sssd-sudo(5) for more information on configuring
sudo
to work with SSSD.
# 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; may be specified multiple times. sudoers_base ou=SUDOers,dc=example,dc=com # # verbose sudoers matching from ldap #sudoers_debug 2 # # Enable support for time-based entries in sudoers. #sudoers_timed yes # # 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 user name> # rootuse_sasl yes # rootsasl_auth_id <SASL user name for root access> # sasl_secprops none # krb5_ccname /etc/.ldapcache
sudo
source and binary distributions as
schema.OpenLDAP. 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 ) attributetype ( 1.3.6.1.4.1.15953.9.1.8 NAME 'sudoNotBefore' DESC 'Start of time interval for which the entry is valid' EQUALITY generalizedTimeMatch ORDERING generalizedTimeOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 ) attributetype ( 1.3.6.1.4.1.15953.9.1.9 NAME 'sudoNotAfter' DESC 'End of time interval for which the entry is valid' EQUALITY generalizedTimeMatch ORDERING generalizedTimeOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 ) attributeTypes ( 1.3.6.1.4.1.15953.9.1.10 NAME 'sudoOrder' DESC 'an integer to order the sudoRole entries' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 ) 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 $ sudoNotBefore $ sudoNotAfter $ sudoOrder $ description ) )
sudo
,
please submit a bug report at https://bugzilla.sudo.ws/
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 https://www.sudo.ws/license.html
for complete details.