sudoers.ldap - sudo LDAP configuration
Please see following description for synopsis
SUDOERS.LDAP(5) BSD File Formats Manual SUDOERS.LDAP(5)
NAME
sudoers.ldap -- sudo LDAP configuration
DESCRIPTION
In addition to the standard sudoers file, 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:
o 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.
o It is possible to specify per-entry options that override the global
default options. /etc/sudoers only supports default options and lim-
ited 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.
o 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 special-
ized tool to check syntax.
SUDOers LDAP container
The sudoers configuration is contained in the ou=SUDOers LDAP container.
Sudo first looks for the cn=defaults 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=my-domain,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 attributes:
sudoUser
A user name, user-ID (prefixed with `#'), Unix group name or ID
(prefixed with `%' or `%#' respectively), user netgroup (prefixed
with `+'), or non-Unix group name or ID (prefixed with `%:' or
`%:#' respectively). User netgroups are matched using the user and
domain members only; the host member is not used when matching.
Non-Unix group support is only available when an appropriate
group_plugin is defined in the global defaults sudoRole object. If
a sudoUser entry is preceded by an exclamation point, `!', and the
entry matches, the sudoRole in which it resides will be ignored.
Negated sudoUser entries are only supported by version 1.9.9 or
higher.
sudoHost
A host name, IP address, IP network, or host netgroup (prefixed
with a `+'). The special value ALL will match any host. Host net-
groups are matched using the host (both qualified and unqualified)
and domain members only; the user member is not used when matching.
If a sudoHost entry is preceded by an exclamation point, `!', and
the entry matches, the sudoRole in which it resides will be
ignored. Negated sudoHost entries are only supported by version
1.8.18 or higher.
sudoCommand
A fully-qualified Unix command name with optional command line
arguments, potentially including globbing characters (aka wild
cards). If a command name is preceded by an exclamation point,
`!', 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 fol-
lowed by a colon (`:') and then the actual digest, in either hex or
base64 format. For example, given the following value for sudoCom-
mand:
sha224:0GomF8mNN3wlDt1HD9XldjJ3SNgpFdbjO1+NsQ /bin/ls
The user may only run /bin/ls if its sha224 digest matches the
specified value. Command digests are only supported by version
1.8.7 or higher.
sudoOption
Identical in function to the global options described above, but
specific to the sudoRole in which it resides.
sudoRunAsUser
A user name or user-ID (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. If a sudoRunAsUser
entry is preceded by an exclamation point, `!', and the entry
matches, the sudoRole in which it resides will be ignored. If
sudoRunAsUser is specified but empty, it will match the invoking
user. If neither sudoRunAsUser nor sudoRunAsGroup are present, the
value of the runas_default sudoOption is used (defaults to root).
The sudoRunAsUser attribute is only available in sudo versions
1.7.0 and higher. Older versions of sudo use the sudoRunAs
attribute instead. Negated sudoRunAsUser entries are only sup-
ported by version 1.8.26 or higher.
sudoRunAsGroup
A Unix group or group-ID (prefixed with `#') that commands may be
run as. The special value ALL will match any group. If a
sudoRunAsGroup entry is preceded by an exclamation point, `!', and
the entry matches, the sudoRole in which it resides will be
ignored.
The sudoRunAsGroup attribute is only available in sudo versions
1.7.0 and higher. Negated sudoRunAsGroup entries are only sup-
ported by version 1.8.26 or higher.
sudoNotBefore
A timestamp in the form 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.
sudoNotAfter
A timestamp in the form yyyymmddHHMMSSZ that indicates an expira-
tion date/time, after which the sudoRole will no longer be valid.
If multiple sudoNotAfter 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 (con-
trary 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.
sudoOrder
The 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
order 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.
Each attribute listed above should contain a single value, but there may
be multiple instances of each attribute 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=my-domain,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 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 direc-
tive, 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 net-
groups the user belongs to before the sudoers query. This makes it pos-
sible 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 per-
formed by sudo are as follows:
1. Match all 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.
2. Repeated queries are performed to find any nested nisNetgroup
records with a memberNisNetgroup entry that refers to an already-
matched record.
For sites with a large number of netgroups, using NETGROUP_BASE can sig-
nificantly speed up sudo's execution time.
Differences between LDAP and non-LDAP sudoers
One of the major differences between LDAP and file-based sudoers is that
in LDAP, sudo-specific Aliases are not supported.
For the most part, there is little 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.
There are also some subtle differences in the way sudoers is handled once
in LDAP. Probably the biggest is that according to the RFC, LDAP order-
ing is arbitrary and you cannot expect that Attributes and Entries are
returned in any specific order.
The order in which different entries are applied can be controlled using
the 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 para-
noid 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
Converting between file-based and LDAP sudoers
The cvtsudoers(1) utility can be used to convert between file-based and
LDAP sudoers. However, there are features in the file-based sudoers that
have no equivalent in LDAP-based sudoers (and vice versa). These cannot
be converted automatically.
For example, a Cmnd_Alias in a sudoers file may be converted to a
sudoRole that contains multiple commands. Multiple users and/or groups
may be assigned to the sudoRole.
Also, host, user, runas, and command-based Defaults entries are not sup-
ported. However, a sudoRole may contain one or more sudoOption
attributes which can often serve the same purpose.
Consider the following sudoers lines:
Cmnd_Alias PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less
Defaults!PAGERS noexec
alice, bob ALL = ALL
In this example, alice and bob are allowed to run all commands, but the
commands listed in PAGERS will have the noexec flag set, preventing shell
escapes.
When converting this to LDAP, two sudoRole objects can be used:
dn: cn=PAGERS,ou=SUDOers,dc=my-domain,dc=com
objectClass: top
objectClass: sudoRole
cn: PAGERS
sudoUser: alice
sudoUser: bob
sudoHost: ALL
sudoCommand: /usr/bin/more
sudoCommand: /usr/bin/pg
sudoCommand: /usr/bin/less
sudoOption: noexec
sudoOrder: 900
dn: cn=ADMINS,ou=SUDOers,dc=my-domain,dc=com
objectClass: top
objectClass: sudoRole
cn: ADMINS
sudoUser: alice
sudoUser: bob
sudoHost: ALL
sudoCommand: ALL
sudoOrder: 100
In the LDAP version, the sudoOrder attribute is used to guarantee that
the PAGERS sudoRole with noexec has precedence. Unlike the sudoers ver-
sion, the LDAP version requires that all users for whom the restriction
should apply be assigned to the PAGERS sudoRole. Using a Unix group or
netgroup in PAGERS rather than listing each user would make this easier
to maintain.
Per-user Defaults entries can be emulated by using one or more sudoOption
attributes in a sudoRole. Consider the following sudoers lines:
User_Alias ADMINS = john, sally
Defaults:ADMINS !authenticate
ADMINS ALL = (ALL:ALL) ALL
In this example, john and sally are allowed to run any command as any
user or group.
When converting this to LDAP, we can use a Unix group instead of the
User_Alias.
dn: cn=admins,ou=SUDOers,dc=my-domain,dc=com
objectClass: top
objectClass: sudoRole
cn: admins
sudoUser: %admin
sudoHost: ALL
sudoRunAsUser: ALL
sudoRunAsGroup: ALL
sudoCommand: ALL
sudoOption: !authenticate
This assumes that users john and sally are members of the ``admins'' Unix
group.
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.
The sudo distribution includes versions of the sudoers schema for multi-
ple LDAP servers:
schema.OpenLDAP
OpenLDAP slapd and OpenBSD ldapd
schema.olcSudo
OpenLDAP slapd 2.3 and higher when on-line configuration is enabled
schema.iPlanet
Netscape-derived servers such as the iPlanet, Oracle, and 389
Directory Servers
schema.ActiveDirectory
Microsoft Active Directory
The schema in OpenLDAP format is also included in the EXAMPLES section.
Configuring ldap.conf
Sudo reads the /etc/ldap.conf file for LDAP-specific configuration. Typ-
ically, this file is shared between different LDAP-aware clients. As
such, most of the settings are not 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(5) 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.
sudo supports a variety of LDAP library implementations, including OpenL-
DAP, Netscape-derived (also used by Solaris and HP-UX), and IBM LDAP (aka
Tivoli). Some options are specific to certain LDAP implementations or
have implementation-specific behavior. These differences are noted below
where applicable.
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.
Lines beginning with a pound sign (`#') are ignored. Leading white space
is removed from the beginning of lines.
BIND_TIMELIMIT seconds
The BIND_TIMELIMIT parameter specifies the amount of time, in sec-
onds, to wait while trying to connect to an LDAP server. If multi-
ple URIs or HOSTs are specified, this is the amount of time to wait
before trying the next one in the list.
BINDDN DN
The BINDDN parameter specifies the identity, in the form of a Dis-
tinguished 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. The secret may be a plaintext password or a
base64-encoded string with a ``base64:'' prefix. For example:
BINDPW base64:dGVzdA==
If a plaintext password is used, it should be a simple string with-
out quotes. Plain text passwords may not include the comment char-
acter (`#') and the escaping of special characters with a backslash
(`\') is not supported.
DEREF never/searching/finding/always
How alias dereferencing is to be performed when searching. See the
ldap.conf(5) manual for a full description of this option.
HOST name[:port] ...
If no URI is specified (see below), the HOST parameter specifies a
white space-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 backward compatibility only.
KRB5_CCNAME file name
The path to the Kerberos 5 credential cache to use when authenti-
cating with the remote server.
This option is only relevant when using SASL authentication (see
below).
LDAP_VERSION number
The version of the LDAP protocol to use when connecting to the
server. The default value is protocol version 3.
NETGROUP_BASE base
The base DN to use when performing LDAP netgroup queries. Typi-
cally this is of the form ou=netgroup,dc=my-domain,dc=com for the
domain my-domain.com. Multiple NETGROUP_BASE lines may be speci-
fied, 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 modification 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 )
NETGROUP_SEARCH_FILTER ldap_filter
An LDAP filter which is used to restrict the set of records
returned when performing an LDAP netgroup query. Typically, this
is of the form 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 used when querying netgroups directly via LDAP.
NETWORK_TIMEOUT seconds
An alias for BIND_TIMELIMIT provided for OpenLDAP 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 backward compatibility only.
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 the or the path specified by the
ldap_secret plugin argument in sudo.conf(5), which defaults to
/etc/ldap.secret. If no ROOTBINDDN is specified, the BINDDN iden-
tity is used (if any).
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.
SASL_AUTH_ID identity
The SASL user name to use when connecting to the LDAP server. By
default, sudo will use an anonymous connection.
This option is only relevant when using SASL authentication.
SASL_MECH mechanisms
A white space-delimited list of SASL authentication mechanisms to
use. By default, sudo will use GSSAPI authentication.
SASL_SECPROPS none/properties
SASL security properties or none for no properties. See the SASL
programmer's manual for details.
This option is only relevant when using SASL authentication.
SSL on/true/yes/off/false/no
If the SSL parameter is set to on, true, or yes TLS (SSL) encryp-
tion is always used when communicating with the LDAP server. Typi-
cally, 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 connec-
tion 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 IBM Tivoli Directory servers.
SUDOERS_BASE base
The base DN to use when performing sudo LDAP queries. Typically
this is of the form ou=SUDOers,dc=my-domain,dc=com for the domain
my-domain.com. Multiple SUDOERS_BASE lines may be specified, in
which case they are queried in the order specified.
SUDOERS_DEBUG debug_level
This sets the debug level for sudo LDAP queries. Debugging infor-
mation 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.
SUDOERS_SEARCH_FILTER ldap_filter
An LDAP filter which is used to restrict the set of records
returned when performing a 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.
SUDOERS_TIMED on/true/yes/off/false/no
Whether or not to evaluate the sudoNotBefore and sudoNotAfter
attributes that implement time-dependent sudoers entries.
TIMELIMIT seconds
The TIMELIMIT parameter specifies the amount of time, in seconds,
to wait for a response to an LDAP query.
TIMEOUT seconds
The TIMEOUT parameter specifies the amount of time, in seconds, to
wait for a response from the various LDAP APIs.
TLS_CACERT file name
An alias for TLS_CACERTFILE for OpenLDAP compatibility.
TLS_CACERTFILE file name
The path to a certificate authority bundle which contains the cer-
tificates 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. Netscape-
derived LDAP libraries use the same certificate database for CA and
client certificates (see TLS_CERT).
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 certifi-
cate type depends on the LDAP libraries used.
OpenLDAP:
tls_cert /etc/ssl/client_cert.pem
Netscape-derived:
tls_cert /var/ldap/cert7.db
IBM LDAP:
Unused, the key database specified by TLS_KEY contains both
keys and certificates.
When using Netscape-derived libraries, this file may also contain
Certificate Authority certificates.
TLS_CHECKPEER on/true/yes/off/false/no
If enabled, TLS_CHECKPEER will cause the LDAP server's TLS certifi-
cated 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. Note that disabling the check cre-
ates 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 IBM LDAP libraries.
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
IBM LDAP:
tls_key /usr/ldap/ldapkey.kdb
When using IBM LDAP libraries, this file may also contain Certifi-
cate Authority and client certificates and may be encrypted.
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 OpenLDAP or IBM Tivoli Directory Server manual for a list of
valid ciphers.
This option is not supported by Netscape-derived libraries.
TLS_KEYPW secret
The TLS_KEYPW contains the password used to decrypt the key data-
base on clients using the IBM LDAP library. The secret may be a
plaintext password or a base64-encoded string with a ``base64:''
prefix. For example:
TLS_KEYPW base64:dGVzdA==
If a plaintext password is used, it should be a simple string with-
out quotes. Plain text passwords may not include the comment char-
acter (`#') 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. Alter-
nately, 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 speci-
fied by TLS_KEY, but use a .sth file extension instead of .kdb,
e.g., ldapkey.sth. The default ldapkey.kdb that ships with the IBM
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 IBM LDAP libraries.
TLS_REQCERT level
The TLS_REQCERT parameter controls how the LDAP server's TLS cer-
tificated will be verified (if at all). If the server's TLS cer-
tificate cannot be verified (usually because it is signed by an
unknown certificate authority), sudo will be unable to connect to
it. The following level values are supported:
never The server certificate will not be requested or
checked.
allow The server certificate will be requested. A missing
or invalid certificate is ignored and not considered
an error.
try The server certificate will be requested. A missing
certificate is ignored but an invalid certificate
will result in a connection error.
demand | hard
The server certificate will be requested. A missing
or invalid certificate will result in a connection
error. This is the default behavior.
This option is only supported by the OpenLDAP libraries. Other
LDAP libraries only support the TLS_CHECKPEER parameter.
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.
URI ldap[s]://[hostname[:port]] ...
Specifies a white space-delimited list of one or more URIs describ-
ing the LDAP server(s) to connect to. The protocol may be either
ldap 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. Multiple URI lines are treated
identically to a URI line containing multiple entries. Only sys-
tems using the OpenSSL libraries support the mixing of ldap:// and
ldaps:// URIs. Both the Netscape-derived and IBM LDAP libraries
used on most commercial versions of Unix are only capable of sup-
porting one or the other.
USE_SASL on/true/yes/off/false/no
Enable USE_SASL for LDAP servers that support SASL authentication.
ROOTSASL_AUTH_ID identity
The SASL user name to use when ROOTUSE_SASL is enabled.
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 by default, sudo does not stop searching
after the first match and later matches take precedence over earlier ones
(unless [SUCCESS=return] is used, see below). The following sources are
recognized:
files read sudoers from /etc/sudoers
ldap read sudoers from LDAP
In addition, a subset of nsswitch.conf-style action statements is sup-
ported, specifically [SUCCESS=return] and [NOTFOUND=return]. These will
unconditionally terminate the search if the user was either found
([SUCCESS=return]) or not found ([NOTFOUND=return]) in the immediately
preceding source. Other action statements tokens are not supported, nor
is test negation with `!'.
To consult LDAP first followed by the local sudoers file (if it exists),
use:
sudoers: ldap files
To consult LDAP only when no match is found in the local sudoers file (if
it exists), use:
sudoers: files [SUCCESS=return] ldap
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 oper-
ating system does not use an nsswitch.conf file, except on AIX (see
below).
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 authoritative 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 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
Integration with sssd
On systems with the System Security Services Daemon (SSSD) and where 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
sss 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.
FILES
/etc/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; may be specified multiple times.
sudoers_base ou=SUDOers,dc=my-domain,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 Netscape-derived 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
Sudoers schema for OpenLDAP
The following schema, in OpenLDAP format, is included with 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. Sites using the optional on-line
configuration supported by OpenLDAP 2.3 and higher should apply the
schema.olcSudo file instead.
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 )
attributetype ( 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 )
)
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+-----------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------------+
|Availability | security/sudo |
+---------------+-----------------------+
|Stability | Pass-through volatile |
+---------------+-----------------------+
SEE ALSO
cvtsudoers(1), ldap.conf(5), sssd-sudo(5), sudo.conf(5), sudoers(5)
AUTHORS
Many people have worked on sudo over the years; this version consists of
code written primarily by:
Todd C. Miller
See the CONTRIBUTORS file in the sudo distribution
(https://www.sudo.ws/contributors.html) for an exhaustive list of people
who have contributed to sudo.
CAVEATS
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
https://bugzilla.sudo.ws/
SUPPORT
Limited free support is available via the sudo-users mailing list, see
https://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, includ-
ing, 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.
NOTES
Source code for open source software components in Oracle Solaris can be
found at https://www.oracle.com/downloads/opensource/solaris-source-code-
downloads.html.
This software was built from source available at https://github.com/ora-
cle/solaris-userland. The original community source was downloaded from
https://www.sudo.ws/sudo/dist/sudo-1.9.9.tar.gz.
Further information about this software can be found on the open source
community website at https://www.sudo.ws/.
Sudo 1.9.9 January 27, 2022 Sudo 1.9.9