Provided by: slapd_2.5.13+dfsg-1ubuntu1_amd64 bug


       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), slapmodify(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
       definitions 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
       information.  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
              (specified 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
       <control> 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

       <control>  clause.  This implicit <control> stops access directive evaluation with no more
       access privileges granted to anyone else.  To stop access directive evaluation  only  when
       both <who> and <what> match, add an explicit

            by * break

       to the end of the <who> clause list.

       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
       addition,  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.
       Substring 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
       character 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
       NameAndOptionalUID 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 evaluated in a dynamic group, by searching the local server only.

       The   statements   peername=<peername>,    sockname=<sockname>,    domain=<domain>,    and
       sockurl=<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
       compared  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
       <peername> 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
       <peername>=<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
       privileges, 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,
       peername.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,    will    match,   but   will   not   match  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
       checking 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
       operational attribute is used.  ACIs are experimental; they must  be  enabled  at  compile

       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
       positive 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
       privilege  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.  This  access  allows  some modifications which would otherwise be
       prohibited by the LDAP data model or the directory schema, e.g.  changing  the  structural
       objectclass of an entry, or modifying an operational attribute that is defined as not user
       modifiable.  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
       authentication/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 passwords.

       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
       privileges will be only those defined by the clause.  The + and - signs add/remove  access
       privileges 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
       disclose.   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
       authenticated clients.

       One  useful  application  is  to  easily  grant  write  privileges  to an updatedn that is
       different 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 MDB database backend. Requirements 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
       parent.  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)
       privileges on the attribute the credentials are stored in (usually userPassword).

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

       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
       continuation  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-mdb(5).

       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" (


       OpenLDAP   Software   is   developed   and   maintained   by    The    OpenLDAP    Project
       <>.   OpenLDAP Software is derived from the University of Michigan
       LDAP 3.3 Release.