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SLAPD.ACCESS(5)                        File Formats Manual                        SLAPD.ACCESS(5)

       slapd.access - access configuration for slapd, the stand-alone LDAP daemon


       The  slapd.conf(5)  file  contains configuration information for the slapd(8) daemon. This
       configuration file is also used by the SLAPD tools  slapacl(8),  slapadd(8),  slapauth(8),
       slapcat(8), slapdn(8), slapindex(8), and slaptest(8).

       The  slapd.conf  file  consists  of a series of global configuration options that apply to
       slapd as a whole (including all backends), followed by zero or more database backend defi‐
       nitions that contain information specific to a backend instance.

       The general format of slapd.conf is as follows:

           # comment - these options apply to every database
           <global configuration options>
           # first database definition & configuration options
           database    <backend 1 type>
           <configuration options specific to backend 1>
           # subsequent database definitions & configuration options

       Both  the global configuration and each backend-specific section can contain access infor‐
       mation.  Backend-specific access control directives are used for those entries that belong
       to  the  backend, according to their naming context.  In case no access control directives
       are defined for a backend or those which are defined are not  applicable,  the  directives
       from the global configuration section are then used.

       If  no  access controls are present, the default policy allows anyone and everyone to read
       anything but restricts updates to rootdn.  (e.g., "access to * by * read").

       When dealing with an access list, because the global access list is  effectively  appended
       to  each  per-database  list, if the resulting list is non-empty then the access list will
       end with an implicit access to * by * none directive. If there are  no  access  directives
       applicable to a backend, then a default read is used.

       Be warned: the rootdn can always read and write EVERYTHING!

       For entries not held in any backend (such as a root DSE), the global directives are used.

       Arguments that should be replaced by actual text are shown in brackets <>.

       The structure of the access control directives is

       access to <what> [ by <who> [ <access> ] [ <control> ] ]+
              Grant  access (specified by <access>) to a set of entries and/or attributes (speci‐
              fied by <what>) by one or more requestors (specified by <who>).

       Lists of access directives are evaluated in the order they appear in slapd.conf.   When  a
       <what>  clause matches the datum whose access is being evaluated, its <who> clause list is
       checked.  When a <who> clause matches the accessor's properties, its  <access>  and  <con‐
       trol>  clauses  are  evaluated.   Access  control checking stops at the first match of the
       <what> and <who> clause, unless otherwise dictated by the <control>  clause.   Each  <who>
       clause list is implicitly terminated by a

            by * none stop

       clause  that  results  in  stopping  the access control with no access privileges granted.
       Each <what> clause list is implicitly terminated by a

            access to *
                 by * none

       clause that results in granting no access privileges to an otherwise unspecified datum.

       The field <what> specifies the entity the access control directive  applies  to.   It  can
       have the forms

            attrs=<attrlist>[ val[/matchingRule][.<attrstyle>]=<attrval>]



       The  statement  dn=<dnpattern>  selects  the  entries  based on their naming context.  The
       <dnpattern> is a string representation of the entry's DN.  The wildcard * stands  for  all
       the entries, and it is implied if no dn form is given.

       The  <dnstyle> is optional; however, it is recommended to specify it to avoid ambiguities.
       Base (synonym of baseObject), the default, or exact (an alias of base) indicates the entry
       whose  DN is equal to the <dnpattern>; one (synonym of onelevel) indicates all the entries
       immediately below the <dnpattern>, sub (synonym of subtree) indicates all entries  in  the
       subtree  at the <dnpattern>, children indicates all the entries below (subordinate to) the

       If the <dnstyle> qualifier is regex, then <dnpattern> is a  POSIX  (''extended'')  regular
       expression  pattern,  as  detailed  in regex(7) and/or re_format(7), matching a normalized
       string representation of the entry's DN.  The regex form of the  pattern  does  not  (yet)
       support UTF-8.

       The  statement  filter=<ldapfilter>  selects  the  entries based on a valid LDAP filter as
       described in RFC 4515.  A filter of (objectClass=*) is implied if no filter form is given.

       The statement attrs=<attrlist> selects the attributes the access control rule applies  to.
       It  is a comma-separated list of attribute types, plus the special names entry, indicating
       access to the entry itself, and children,  indicating  access  to  the  entry's  children.
       ObjectClass names may also be specified in this list, which will affect all the attributes
       that are required and/or allowed by that objectClass.  Actually, names in <attrlist>  that
       are  prefixed  by  @  are directly treated as objectClass names.  A name prefixed by !  is
       also treated as an objectClass, but in this case the access rule  affects  the  attributes
       that  are  not  required  nor  allowed  by  that  objectClass.  If no attrs form is given,
       attrs=@extensibleObject is implied, i.e. all attributes are addressed.

       Using the form attrs=<attr> val[/matchingRule][.<attrstyle>]=<attrval> specifies access to
       a  particular value of a single attribute.  In this case, only a single attribute type may
       be given. The <attrstyle> exact (the default) uses the attribute's equality matching  rule
       to  compare  the value, unless a different (and compatible) matching rule is specified. If
       the <attrstyle> is regex, the provided value is used as  a  POSIX  (''extended'')  regular
       expression  pattern.   If the attribute has DN syntax, the <attrstyle> can be any of base,
       onelevel, subtree or children, resulting in base, onelevel,  subtree  or  children  match,

       The  dn, filter, and attrs statements are additive; they can be used in sequence to select
       entities the access rule applies to based on naming  context,  value  and  attribute  type
       simultaneously.  Submatches resulting from regex matching can be dereferenced in the <who>
       field using the syntax ${v<n>}, where <n> is the submatch  number.   The  default  syntax,
       $<n>,  is actually an alias for ${d<n>}, that corresponds to dereferencing submatches from
       the dnpattern portion of the <what> field.

       The field <who> indicates whom the access rules apply to.  Multiple <who>  statements  can
       appear  in  an access control statement, indicating the different access privileges to the
       same resource that apply to different accessee.  It can have the forms









            <name>=aci          <pattern>=<attrname>]

       They may be specified in combination.

       The wildcard * refers to everybody.

       The keywords prefixed by real act as  their  counterparts  without  prefix;  the  checking
       respectively occurs with the authentication DN and the authorization DN.

       The  keyword  anonymous  means  access is granted to unauthenticated clients; it is mostly
       used to limit access to authentication resources  (e.g.  the  userPassword  attribute)  to
       unauthenticated clients for authentication purposes.

       The keyword users means access is granted to authenticated clients.

       The  keyword  self means access to an entry is allowed to the entry itself (e.g. the entry
       being accessed and the requesting entry must be  the  same).   It  allows  the  level{<n>}
       style,  where  <n> indicates what ancestor of the DN is to be used in matches.  A positive
       value indicates that the <n>-th ancestor of the user's DN is to be considered; a  negative
       value  indicates that the <n>-th ancestor of the target is to be considered.  For example,
       a "by self.level{1} ..."  clause  would  match  when  the  object  "dc=example,dc=com"  is
       accessed  by  "cn=User,dc=example,dc=com".   A  "by self.level{-1} ..." clause would match
       when the same user accesses the object "ou=Address Book,cn=User,dc=example,dc=com".

       The statement dn=<DN> means that access is granted to the matching DN.  The optional style
       qualifier  dnstyle  allows  the same choices of the dn form of the <what> field.  In addi‐
       tion, the regex style can exploit substring  substitution  of  submatches  in  the  <what>
       dn.regex  clause  by  using  the  form  $<digit>,  with digit ranging from 0 to 9 (where 0
       matches the entire string), or the form ${<digit>+}, for submatches higher than  9.   Sub‐
       string  substitution  from  attribute  value  can  be done in using the form ${v<digit>+}.
       Since the dollar character is used to indicate a substring replacement, the dollar charac‐
       ter that is used to indicate match up to the end of the string must be escaped by a second
       dollar character, e.g.

           access to dn.regex="^(.+,)?uid=([^,]+),dc=[^,]+,dc=com$"
               by dn.regex="^uid=$2,dc=[^,]+,dc=com$$" write

       The style qualifier allows an optional modifier.  At present, the  only  type  allowed  is
       expand, which causes substring substitution of submatches to take place even if dnstyle is
       not regex.  Note that the regex dnstyle in the above example may be of  use  only  if  the
       <by>  clause  needs  to be a regex; otherwise, if the value of the second (from the right)
       dc= portion of the DN in the above example were fixed, the form

           access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
               by dn.exact,expand="uid=$2,dc=example,dc=com" write

       could be used; if it had to match the value in the <what> clause, the form

           access to dn.regex="^(.+,)?uid=([^,]+),dc=([^,]+),dc=com$"
               by dn.exact,expand="uid=$2,dc=$3,dc=com" write

       could be used.

       Forms of the <what>  clause  other  than  regex  may  provide  submatches  as  well.   The
       base(object),  the  sub(tree),  the  one(level),  and the children forms provide $0 as the
       match of the entire string.  The sub(tree), the one(level), and the  children  forms  also
       provide  $1  as the match of the rightmost part of the DN as defined in the <what> clause.
       This may be useful, for instance, to provide access to all the  ancestors  of  a  user  by

           access to dn.subtree="dc=com"
               by dn.subtree,expand="$1" read

       which  means  that  only  access  to  entries  that appear in the DN of the <by> clause is

       The level{<n>} form is an extension and a  generalization  of  the  onelevel  form,  which
       matches  all  DNs  whose  <n>-th  ancestor  is the pattern.  So, level{1} is equivalent to
       onelevel, and level{0} is equivalent to base.

       It is perfectly useless to give any access privileges to a DN  that  exactly  matches  the
       rootdn of the database the ACLs apply to, because it implicitly possesses write privileges
       for the entire tree of that database.   Actually,  access  control  is  bypassed  for  the
       rootdn, to solve the intrinsic chicken-and-egg problem.

       The  statement  dnattr=<attrname>  means  that  access  is granted to requests whose DN is
       listed in the entry being accessed under the <attrname> attribute.

       The statement group=<group> means that access is granted to requests whose DN is listed in
       the  group  entry whose DN is given by <group>.  The optional parameters <objectclass> and
       <attrname> define the objectClass and the member attributeType of the  group  entry.   The
       defaults  are groupOfNames and member, respectively.  The optional style qualifier <style>
       can be expand, which means that <group> will be expanded as a replacement string (but  not
       as a regular expression) according to regex(7) and/or re_format(7), and exact, which means
       that exact match will be used.  If the style of the DN portion of  the  <what>  clause  is
       regex,  the submatches are made available according to regex(7) and/or re_format(7); other
       styles provide limited submatches as discussed above about the DN form of the <by> clause.

       For static groups, the specified attributeType must have DistinguishedName  or  NameAndOp‐
       tionalUID syntax. For dynamic groups the attributeType must be a subtype of the labeledURI
       attributeType. Only LDAP URIs of the form ldap:///<base>??<scope>?<filter> will be  evalu‐
       ated in a dynamic group, by searching the local server only.

       The   statements  peername=<peername>,  sockname=<sockname>,  domain=<domain>,  and  sock‐
       url=<sockurl> mean that the contacting host IP (in the form IP=<ip>:<port>  for  IPv4,  or
       IP=[<ipv6>]:<port>  for  IPv6)  or  the  contacting host named pipe file name (in the form
       PATH=<path> if connecting through a named pipe) for peername, the named pipe file name for
       sockname, the contacting host name for domain, and the contacting URL for sockurl are com‐
       pared against pattern to determine  access.   The  same  style  rules  for  pattern  match
       described  for  the  group case apply, plus the regex style, which implies submatch expand
       and regex match of the corresponding connection parameters.  The exact style of the <peer‐
       name>  clause  (the  default) implies a case-exact match on the client's IP, including the
       IP= prefix and the trailing :<port>, or the client's path, including the PATH=  prefix  if
       connecting  through  a  named pipe.  The special ip style interprets the pattern as <peer‐
       name>=<ip>[%<mask>][{<n>}], where <ip> and <mask> are dotted digit representations of  the
       IP  and  the  mask, while <n>, delimited by curly brackets, is an optional port.  The same
       applies to IPv6 addresses when the special ipv6 style is used.  When checking access priv‐
       ileges,  the  IP  portion of the peername is extracted, eliminating the IP= prefix and the
       :<port> part, and it is compared against the <ip> portion of  the  pattern  after  masking
       with  <mask>:  ((peername  &  <mask>)  == <ip>).  As an example, peername.ip= and
       peername.ipv6=::1     allow     connections      only      from      localhost,      peer‐
       name.ip=  allows connections from any IP in the 192.168.1 class C
       domain, and peername.ip={9009} allows connections from any  IP
       in the 192.168.1.[16-31] range of the same domain, only if port 9009 is used.  The special
       path style eliminates the PATH= prefix from the peername when connecting through  a  named
       pipe,  and  performs an exact match on the given pattern.  The <domain> clause also allows
       the subtree style, which succeeds when a fully qualified name exactly matches  the  domain
       pattern,  or  its  trailing  part,  after  a dot, exactly matches the domain pattern.  The
       expand style is allowed, implying an exact match  with  submatch  expansion;  the  use  of
       expand  as  a  style  modifier is considered more appropriate.  As an example, domain.sub‐
       tree=example.com will match www.example.com, but will  not  match  www.anotherexample.com.
       The  domain  of  the contacting host is determined by performing a DNS reverse lookup.  As
       this lookup can easily be spoofed, use of the domain statement  is  strongly  discouraged.
       By  default,  reverse  lookups  are  disabled.   The optional domainstyle qualifier of the
       <domain> clause allows a modifier option; the only value currently  supported  is  expand,
       which causes substring substitution of submatches to take place even if the domainstyle is
       not regex, much like the analogous usage in <dn> clause.

       The statement set=<pattern> is undocumented yet.

       The statement dynacl/<name>[/<options>][.<dynstyle>][=<pattern>] means that access  check‐
       ing  is delegated to the admin-defined method indicated by <name>, which can be registered
       at run-time by means of the moduleload statement.  The fields  <options>,  <dynstyle>  and
       <pattern> are optional, and are directly passed to the registered parsing routine.  Dynacl
       is experimental; it must be enabled at compile time.

       The statement dynacl/aci[=<attrname>] means that the access control is determined  by  the
       values  in  the  attrname  of  the  entry  itself.  The optional <attrname> indicates what
       attributeType holds the ACI information in the entry.  By default, the OpenLDAPaci  opera‐
       tional attribute is used.  ACIs are experimental; they must be enabled at compile time.

       The  statements  ssf=<n>, transport_ssf=<n>, tls_ssf=<n>, and sasl_ssf=<n> set the minimum
       required Security Strength Factor (ssf) needed to grant access.  The value should be posi‐
       tive integer.

       The  optional  field <access> ::= [[real]self]{<level>|<priv>} determines the access level
       or the specific access privileges the who field will have.  Its component are defined as

            <level> ::= none|disclose|auth|compare|search|read|{write|add|delete}|manage
            <priv> ::= {=|+|-}{0|d|x|c|s|r|{w|a|z}|m}+

       The modifier self allows special operations like having a certain access level  or  privi‐
       lege  only  in  case  the  operation  involves  the name of the user that's requesting the
       access.  It implies the user that requests access is authorized.   The  modifier  realself
       refers  to  the authenticated DN as opposed to the authorized DN of the self modifier.  An
       example is the selfwrite access to the member attribute of a group, which  allows  one  to
       add/delete  its  own DN from the member list of a group, while being not allowed to affect
       other members.

       The level access model relies on an incremental interpretation of the  access  privileges.
       The  possible  levels  are none, disclose, auth, compare, search, read, write, and manage.
       Each access level implies all the preceding ones, thus manage grants all access  including
       administrative  access.   The  write access is actually the combination of add and delete,
       which respectively restrict the write privilege to add or delete the specified <what>.

       The none access level disallows all access including disclosure on error.

       The disclose access level allows disclosure of information on error.

       The auth access level means that one is allowed access to an attribute to perform  authen‐
       tication/authorization  operations  (e.g.   bind) with no other access.  This is useful to
       grant unauthenticated clients the least possible access level to critical resources,  like

       The priv access model relies on the explicit setting of access privileges for each clause.
       The = sign resets previously defined accesses; as a consequence, the final  access  privi‐
       leges will be only those defined by the clause.  The + and - signs add/remove access priv‐
       ileges to the existing ones.  The privileges are m for manage, w for write, a for  add,  z
       for  delete, r for read, s for search, c for compare, x for authentication, and d for dis‐
       close.  More than one of the above privileges can be added in one statement.  0  indicates
       no privileges and is used only by itself (e.g., +0).  Note that +az is equivalent to +w.

       If no access is given, it defaults to +0.

       The  optional  field  <control> controls the flow of access rule application.  It can have
       the forms


       where stop, the default, means access checking stops in case  of  match.   The  other  two
       forms  are used to keep on processing access clauses.  In detail, the continue form allows
       for other <who> clauses in the same <access> clause to be considered,  so  that  they  may
       result  in  incrementally  altering  the privileges, while the break form allows for other
       <access> clauses that match the same target to be processed.  Consider the (silly) example

            access to dn.subtree="dc=example,dc=com" attrs=cn
                 by * =cs break

            access to dn.subtree="ou=People,dc=example,dc=com"
                 by * +r

       which allows search and compare privileges  to  everybody  under  the  "dc=example,dc=com"
       tree,  with  the  second  rule allowing also read in the "ou=People" subtree, or the (even
       more silly) example

            access to dn.subtree="dc=example,dc=com" attrs=cn
                 by * =cs continue
                 by users +r

       which grants everybody search and compare privileges, and adds read privileges to  authen‐
       ticated clients.

       One  useful application is to easily grant write privileges to an updatedn that is differ‐
       ent from the rootdn.  In this case, since the updatedn needs write access to (almost)  all
       data, one can use

            access to *
                 by dn.exact="cn=The Update DN,dc=example,dc=com" write
                 by * break

       as  the  first  access rule.  As a consequence, unless the operation is performed with the
       updatedn identity, control is passed straight to the subsequent rules.

       Operations require different privileges on different portions of entries.   The  following
       summary  applies to primary database backends such as the BDB and HDB backends.   Require‐
       ments for other backends may (and often do) differ.

       The add operation requires add (=a) privileges on the pseudo-attribute entry of the  entry
       being  added, and add (=a) privileges on the pseudo-attribute children of the entry's par‐
       ent.  When adding the suffix entry of a database, add access to children of the  empty  DN
       ("")  is  required.  Also  if Add content ACL checking has been configured on the database
       (see the slapd.conf(5) or slapd-config(5) manual page), add (=a) will be required  on  all
       of the attributes being added.

       The bind operation, when credentials are stored in the directory, requires auth (=x) priv‐
       ileges on the attribute the credentials are stored in (usually userPassword).

       The compare operation requires compare (=c) privileges on the attribute that is being com‐

       The  delete operation requires delete (=z) privileges on the pseudo-attribute entry of the
       entry being deleted, and delete (=d) privileges on the children  pseudo-attribute  of  the
       entry's parent.

       The  modify operation requires write (=w) privileges on the attributes being modified.  In
       detail, add (=a) is required to add new values, delete (=z) is required to delete existing
       values,  and  both  delete  and add (=az), or write (=w), are required to replace existing

       The modrdn operation requires write (=w) privileges on the pseudo-attribute entry  of  the
       entry  whose relative DN is being modified, delete (=z) privileges on the pseudo-attribute
       children of the old entry's parents, add (=a) privileges on the pseudo-attribute  children
       of  the new entry's parents, and add (=a) privileges on the attributes that are present in
       the new relative DN.  Delete (=z) privileges are also required on the attributes that  are
       present in the old relative DN if deleteoldrdn is set to 1.

       The search operation, requires search (=s) privileges on the entry pseudo-attribute of the
       searchBase (NOTE: this was introduced with  OpenLDAP  2.4).   Then,  for  each  entry,  it
       requires  search  (=s)  privileges  on the attributes that are defined in the filter.  The
       resulting entries are finally tested for read  (=r)  privileges  on  the  pseudo-attribute
       entry (for read access to the entry itself) and for read (=r) access on each value of each
       attribute that is requested.  Also, for each referral object used in generating  continua‐
       tion  references,  the  operation  requires read (=r) access on the pseudo-attribute entry
       (for read access to the referral object itself), as  well  as  read  (=r)  access  to  the
       attribute holding the referral information (generally the ref attribute).

       Some  internal  operations  and  some  controls  require  specific access privileges.  The
       authzID mapping and the proxyAuthz  control  require  auth  (=x)  privileges  on  all  the
       attributes  that  are  present in the search filter of the URI regexp maps (the right-hand
       side of the authz-regexp directives).  Auth (=x)  privileges  are  also  required  on  the
       authzTo  attribute  of  the  authorizing identity and/or on the authzFrom attribute of the
       authorized identity.  In general, when an internal lookup is performed for  authentication
       or authorization purposes, search-specific privileges (see the access requirements for the
       search operation illustrated above) are relaxed to auth.

       Access control to search entries is checked by the frontend, so it is fully honored by all
       backends;  for  all  other operations and for the discovery phase of the search operation,
       full ACL semantics is only supported by  the  primary  backends,  i.e.   back-bdb(5),  and

       Some  other  backend,  like back-sql(5), may fully support them; others may only support a
       portion of the described semantics, or even differ in some aspects.  The relevant  details
       are described in the backend-specific man pages.

       It  is strongly recommended to explicitly use the most appropriate <dnstyle> in <what> and
       <who> clauses, to avoid possible incorrect specifications of the access rules as  well  as
       for performance (avoid unnecessary regex matching when an exact match suffices) reasons.

       An administrator might create a rule of the form:

            access to dn.regex="dc=example,dc=com"
                 by ...

       expecting  it to match all entries in the subtree "dc=example,dc=com".  However, this rule
       actually matches any DN which contains anywhere the substring  "dc=example,dc=com".   That
       is, the rule matches both "uid=joe,dc=example,dc=com" and "dc=example,dc=com,uid=joe".

       To match the desired subtree, the rule would be more precisely written:

            access to dn.regex="^(.+,)?dc=example,dc=com$"
                 by ...

       For performance reasons, it would be better to use the subtree style.

            access to dn.subtree="dc=example,dc=com"
                 by ...

       When  writing  submatch  rules,  it may be convenient to avoid unnecessary regex <dnstyle>
       use; for instance, to allow access to the subtree of the  user  that  matches  the  <what>
       clause, one could use

            access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
                 by dn.regex="^uid=$2,dc=example,dc=com$$" write
                 by ...

       However,  since  all  that  is  required in the <by> clause is substring expansion, a more
       efficient solution is

            access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
                 by dn.exact,expand="uid=$2,dc=example,dc=com" write
                 by ...

       In fact, while a <dnstyle> of regex implies substring expansion, exact, as well as all the
       other DN specific <dnstyle> values, does not, so it must be explicitly requested.

              default slapd configuration file

       slapd(8), slapd-*(5), slapacl(8), regex(7), re_format(7)

       "OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)

       OpenLDAP  Software  is developed and maintained by The OpenLDAP Project <http://www.openl‐
       dap.org/>.  OpenLDAP Software is derived from University of Michigan LDAP 3.3 Release.

OpenLDAP                                    2014/09/20                            SLAPD.ACCESS(5)

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