These slapd.conf options apply to the LDAP backend database.
That is, they must follow a "database ldap" line and come before
any subsequent "backend" or "database" lines. Other database
options are described in the slapd.conf(5) manual page.
Note: In early versions of back-ldap it was recommended to always
set
lastmod off
for ldap and meta databases. This was required because
operational attributes related to entry creation and modification
should not be proxied, as they could be mistakenly written to the
target server(s), generating an error. The current
implementation automatically sets lastmod to off, so its use is
redundant and should be omitted.
uri <ldapurl>
LDAP server to use. Multiple URIs can be set in a single
ldapurl argument, resulting in the underlying library
automatically calling the first server of the list that
responds, e.g.
uri "ldap://host/ ldap://backup-host/"
The URI list is space- or comma-separated. Whenever the
server that responds is not the first one in the list, the
list is rearranged and the responsive server is moved to
the head, so that it will be first contacted the next time
a connection needs to be created.
acl-bind bindmethod=simple|sasl [binddn=<simple DN>]
[credentials=<simple password>] [saslmech=<SASL mech>]
[secprops=<properties>] [realm=<realm>]
[authcId=<authentication ID>] [authzId=<authorization ID>]
[starttls=no|yes|critical] [tls_cert=<file>]
[tls_key=<file>] [tls_cacert=<file>]
[tls_cacertdir=<path>]
[tls_reqcert=never|allow|try|demand]
[tls_reqsan=never|allow|try|demand]
[tls_cipher_suite=<ciphers>] [tls_ecname=<names>]
[tls_protocol_min=<major>[.<minor>]]
[tls_crlcheck=none|peer|all]
Allows one to define the parameters of the authentication
method that is internally used by the proxy to collect
info related to access control, and whenever an operation
occurs with the identity of the rootdn of the LDAP proxy
database. The identity defined by this directive,
according to the properties associated to the
authentication method, is supposed to have read access on
the target server to attributes used on the proxy for ACL
checking.
There is no risk of giving away such values; they are only
used to check permissions. The default is to use simple
bind, with empty binddn and credentials, which means that
the related operations will be performed anonymously. If
not set, and if idassert-bind is defined, this latter
identity is used instead. See idassert-bind for details.
The connection between the proxy database and the remote
server associated to this identity is cached regardless of
the lifespan of the client-proxy connection that first
established it.
This identity is not implicitly used by the proxy when the
client connects anonymously. The idassert-bind feature,
instead, in some cases can be crafted to implement that
behavior, which is intrinsically unsafe and should be used
with extreme care.
The TLS settings default to the same as the main slapd TLS
settings, except for tls_reqcert which defaults to
"demand", and tls_reqsan which defaults to "allow".
cancel {ABANDON|ignore|exop[-discover]}
Defines how to handle operation cancellation. By default,
abandon is invoked, so the operation is abandoned
immediately. If set to ignore, no action is taken and any
further response is ignored; this may result in further
response messages to be queued for that connection, so it
is recommended that long lasting connections are timed out
either by idle-timeout or conn-ttl, so that resources
eventually get released. If set to exop, a cancel
operation (RFC 3909) is issued, resulting in the
cancellation of the current operation; the cancel
operation waits for remote server response, so its use may
not be recommended. If set to exop-discover, support of
the cancel extended operation is detected by reading the
remote server's root DSE.
chase-referrals {YES|no}
enable/disable automatic referral chasing, which is
delegated to the underlying libldap, with rebinding
eventually performed if the rebind-as-user directive is
used. The default is to chase referrals.
conn-pool-max <int>
This directive defines the maximum size of the privileged
connections pool.
conn-ttl <time>
This directive causes a cached connection to be dropped
after a given ttl, regardless of being idle or not. If a
client connection outlives the remote connection, the
client will receive LDAP_UNAVAILABLE when it executes the
next operation.
idassert-authzFrom <authz-regexp>
if defined, selects what local identities are authorized
to exploit the identity assertion feature. The string
<authz-regexp> mostly follows the rules defined for the
authzFrom attribute. See slapd.conf(5), section related
to authz-policy, for details on the syntax of this field.
This parameter differs from the documented behavior in
relation to the meaning of *, which in this case allows
anonymous rather than denies.
idassert-bind bindmethod=none|simple|sasl [binddn=<simple DN>]
[credentials=<simple password>] [saslmech=<SASL mech>]
[secprops=<properties>] [realm=<realm>]
[authcId=<authentication ID>] [authzId=<authorization ID>]
[authz={native|proxyauthz}] [mode=<mode>] [flags=<flags>]
[starttls=no|yes|critical] [tls_cert=<file>]
[tls_key=<file>] [tls_cacert=<file>]
[tls_cacertdir=<path>]
[tls_reqcert=never|allow|try|demand]
[tls_reqsan=never|allow|try|demand]
[tls_cipher_suite=<ciphers>] [tls_ecname=<names>]
[tls_protocol_min=<version>] [tls_crlcheck=none|peer|all]
Allows one to define the parameters of the authentication
method that is internally used by the proxy to authorize
connections that are authenticated by other databases.
Direct binds are always proxied without any idassert
handling.
The identity defined by this directive, according to the
properties associated to the authentication method, is
supposed to have auth access on the target server to
attributes used on the proxy for authentication and
authorization, and to be allowed to authorize the users.
This requires to have proxyAuthz privileges on a wide set
of DNs, e.g. authzTo=dn.subtree:"", and the remote server
to have authz-policy set to to or both. See slapd.conf(5)
for details on these statements and for remarks and
drawbacks about their usage. The supported bindmethods
are
none|simple|sasl
where none is the default, i.e. no identity assertion is
performed.
The authz parameter is used to instruct the SASL bind to
exploit native SASL authorization, if available; since
connections are cached, this should only be used when
authorizing with a fixed identity (e.g. by means of the
authzDN or authzID parameters). Otherwise, the default
proxyauthz is used, i.e. the proxyAuthz control (Proxied
Authorization, RFC 4370) is added to all operations.
The supported modes are:
<mode> := {legacy|anonymous|none|self}
If <mode> is not present, and authzId is given, the proxy
always authorizes that identity. <authorization ID> can
be
u:<user>
[dn:]<DN>
The former is supposed to be expanded by the remote server
according to the authz rules; see slapd.conf(5) for
details. In the latter case, whether or not the dn:
prefix is present, the string must pass DN validation and
normalization.
The default mode is legacy, which implies that the proxy
will either perform a simple bind as the authcDN or a SASL
bind as the authcID and assert the client's identity when
it is not anonymous. The other modes imply that the proxy
will always either perform a simple bind as the authcDN or
a SASL bind as the authcID, unless restricted by
idassert-authzFrom rules (see below), in which case the
operation will fail; eventually, it will assert some other
identity according to <mode>. Other identity assertion
modes are anonymous and self, which respectively mean that
the empty or the client's identity will be asserted; none,
which means that no proxyAuthz control will be used, so
the authcDN or the authcID identity will be asserted. For
all modes that require the use of the proxyAuthz control,
on the remote server the proxy identity must have
appropriate authzTo permissions, or the asserted
identities must have appropriate authzFrom permissions.
Note, however, that the ID assertion feature is mostly
useful when the asserted identities do not exist on the
remote server.
Flags can be
override,[non-]prescriptive,proxy-authz-[non-]critical,dn-{authzid|whoami}
When the override flag is used, identity assertion takes
place even when the database is authorizing for the
identity of the client, i.e. after binding with the
provided identity, and thus authenticating it, the proxy
performs the identity assertion using the configured
identity and authentication method.
When the prescriptive flag is used (the default),
operations fail with inappropriateAuthentication for those
identities whose assertion is not allowed by the
idassert-authzFrom patterns. If the non-prescriptive flag
is used, operations are performed anonymously for those
identities whose assertion is not allowed by the
idassert-authzFrom patterns.
When the proxy-authz-non-critical flag is used (the
default), the proxyAuthz control is not marked as
critical, in violation of RFC 4370. Use of
proxy-authz-critical is recommended.
When the dn-authzid flag is used, RFC 3829 LDAP
Authorization Identity Controls is used to retrieve the
identity associated to the SASL identity; when the
dn-whoami flag is used, RFC 4532 LDAP Who am I? Operation
is performed after the bind for the same purpose.
The TLS settings default to the same as the main slapd TLS
settings, except for tls_reqcert which defaults to
"demand", and tls_reqsan which defaults to "allow".
The identity associated to this directive is also used for
privileged operations whenever idassert-bind is defined
and acl-bind is not. See acl-bind for details.
idassert-passthru <authz-regexp>
if defined, selects what local identities bypass
the identity assertion feature. Those identities
need to be known by the remote host. The string
<authz-regexp> follows the rules defined for the
authzFrom attribute. See slapd.conf(5), section
related to authz-policy, for details on the syntax
of this field.
idle-timeout <time>
This directive causes a cached connection to be
dropped after it has been idle for the specified
time. If a client connection outlives the remote
connection, the client will receive
LDAP_UNAVAILABLE when it executes the next
operation.
keepalive <idle>:<probes>:<interval>
The keepalive parameter sets the values of idle,
probes, and interval used to check whether a socket
is alive; idle is the number of seconds a
connection needs to remain idle before TCP starts
sending keepalive probes; probes is the maximum
number of keepalive probes TCP should send before
dropping the connection; interval is interval in
seconds between individual keepalive probes. Only
some systems support the customization of these
values; the keepalive parameter is ignored
otherwise, and system-wide settings are used.
tcp-user-timeout <milliseconds>
If non-zero, corresponds to the TCP_USER_TIMEOUT
set on the target connections, overriding the
operating system setting. Only some systems
support the customization of this parameter, it is
ignored otherwise and system-wide settings are
used.
network-timeout <time>
Sets the network timeout value after which
poll(2)/select(2) following a connect(2) returns in
case of no activity. The value is in seconds, and
it can be specified as for idle-timeout.
norefs <NO|yes>
If yes, do not return search reference responses.
By default, they are returned unless request is
LDAPv2.
omit-unknown-schema <NO|yes>
If yes, do not return objectClasses or attributes
that are not known to the local server. The
default is to return all schema elements.
noundeffilter <NO|yes>
If yes, return success instead of searching if a
filter is undefined or contains undefined portions.
By default, the search is propagated after
replacing undefined portions with
(!(objectClass=*)), which corresponds to the empty
result set.
onerr {CONTINUE|stop}
This directive allows one to select the behavior in
case an error is returned by the remote server
during a search. The default, continue, consists
in returning success. If the value is set to stop,
the error is returned to the client.
protocol-version {0,2,3}
This directive indicates what protocol version must
be used to contact the remote server. If set to 0
(the default), the proxy uses the same protocol
version used by the client, otherwise the requested
protocol is used. The proxy returns
unwillingToPerform if an operation that is
incompatible with the requested protocol is
attempted.
proxy-whoami {NO|yes}
Turns on proxying of the WhoAmI extended operation.
If this option is given, back-ldap will replace
slapd's original WhoAmI routine with its own. On
slapd sessions that were authenticated by back-
ldap, the WhoAmI request will be forwarded to the
remote LDAP server. Other sessions will be handled
by the local slapd, as before. This option is
mainly useful in conjunction with Proxy
Authorization.
quarantine <interval>,<num>[;<interval>,<num>[...]]
Turns on quarantine of URIs that returned
LDAP_UNAVAILABLE, so that an attempt to reconnect
only occurs at given intervals instead of any time
a client requests an operation. The pattern is:
retry only after at least interval seconds elapsed
since last attempt, for exactly num times; then use
the next pattern. If num for the last pattern is
"+", it retries forever; otherwise, no more retries
occur. The process can be restarted by resetting
the olcDbQuarantine attribute of the database entry
in the configuration backend.
rebind-as-user {NO|yes}
If this option is given, the client's bind
credentials are remembered for rebinds, when trying
to re-establish a broken connection, or when
chasing a referral, if chase-referrals is set to
yes. Note, however, that connection is not re-
established automatically after it was dropped due
to idle-timeout or conn-ttl .
session-tracking-request {NO|yes}
Adds session tracking control for all requests.
The client's IP and hostname, and the identity
associated to each request, if known, are sent to
the remote server for informational purposes. This
directive is incompatible with setting
protocol-version to 2.
single-conn {NO|yes}
Discards current cached connection when the client
rebinds.
t-f-support {NO|yes|discover}
enable if the remote server supports absolute
filters (see RFC 4526 for details). If set to
discover, support is detected by reading the remote
server's root DSE.
timeout [<op>=]<val> [...]
This directive allows one to set per-operation
timeouts. Operations can be
<op> ::= bind, add, delete, modrdn, modify,
compare, search
The overall duration of the search operation is
controlled either by the timelimit parameter or by
server-side enforced time limits (see timelimit and
limits in slapd.conf(5) for details). This timeout
parameter controls how long the target can be
irresponsive before the operation is aborted.
Timeout is meaningless for the remaining
operations, unbind and abandon, which do not imply
any response, while it is not yet implemented in
currently supported extended operations. If no
operation is specified, the timeout val affects all
supported operations.
Note: if the timelimit is exceeded, the operation
is cancelled (according to the cancel directive);
the protocol does not provide any means to rollback
operations, so the client will not be notified
about the result of the operation, which may
eventually succeeded or not. In case the timeout
is exceeded during a bind operation, the connection
is destroyed, according to RFC4511.
Note: in some cases, this backend may issue binds
prior to other operations (e.g. to bind anonymously
or with some prescribed identity according to the
idassert-bind directive). In this case, the
timeout of the operation that resulted in the bind
is used.
tls {none|[try-]start|[try-]propagate|ldaps} [starttls=no]
[tls_cert=<file>] [tls_key=<file>]
[tls_cacert=<file>] [tls_cacertdir=<path>]
[tls_reqcert=never|allow|try|demand]
[tls_reqsan=never|allow|try|demand]
[tls_cipher_suite=<ciphers>] [tls_ecname=<names>]
[tls_crlcheck=none|peer|all]
Specify TLS settings for regular connections.
If the first parameter is not "none" then this
configures the TLS settings to be used for regular
connections. The StartTLS extended operation will
be used when establishing the connection unless the
URI directive protocol scheme is ldaps://. In that
case this keyword may only be set to "ldaps" and
the StartTLS operation will not be used.
With propagate, the proxy issues StartTLS operation
only if the original connection has a TLS layer set
up. The try- prefix instructs the proxy to
continue operations if the StartTLS operation
failed; its use is not recommended.
The TLS settings default to the same as the main
slapd TLS settings, except for tls_reqcert which
defaults to "demand", tls_reqsan which defaults to
"allow", and starttls which is overshadowed by the
first keyword and thus ignored.
use-temporary-conn {NO|yes}
when set to yes, create a temporary connection
whenever competing with other threads for a shared
one; otherwise, wait until the shared connection is
available.
