Provided by: slapd_2.4.42+dfsg-2ubuntu3.13_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), 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

       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
       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.  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  database  backends  such  as  the  BDB  and  HDB  backends.
       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-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" (


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