.TH SLAPD.ACCESS 5 "RELEASEDATE" "OpenLDAP LDVERSION"
-.\" Copyright 1998-2003 The OpenLDAP Foundation All Rights Reserved.
+.\" Copyright 1998-2011 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply. See COPYRIGHT/LICENSE.
+.\" $OpenLDAP$
.SH NAME
slapd.access \- access configuration for slapd, the stand-alone LDAP daemon
.SH SYNOPSIS
.BR slapd.conf (5)
file contains configuration information for the
.BR slapd (8)
-daemon. This configuration file is also used by the
-.BR slurpd (8)
-replication daemon and by the SLAPD tools
+daemon. This configuration file is also used by the SLAPD tools
+.BR slapacl (8),
.BR slapadd (8),
+.BR slapauth (8),
.BR slapcat (8),
+.BR slapdn (8),
+.BR slapindex (8),
and
-.BR slapindex (8).
+.BR slaptest (8).
.LP
The
.B slapd.conf
not applicable, the directives from the global configuration section
are then used.
.LP
+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").
+.LP
+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
+.B access to * by * none
+directive. If there are no access directives applicable to a backend,
+then a default read is used.
+.LP
+.B Be warned: the rootdn can always read and write EVERYTHING!
+.LP
For entries not held in any backend (such as a root DSE), the
-directives of the first backend (and any global directives) are
-used.
+global directives are used.
.LP
Arguments that should be replaced by actual text are shown in
brackets <>.
.SH THE ACCESS DIRECTIVE
The structure of the access control directives is
.TP
-.B access to <what> "[ by <who> <access> [ <control> ] ]+"
+.B access to <what> "[ by <who> [ <access> ] [ <control> ] ]+"
Grant access (specified by
.BR <access> )
to a set of entries and/or attributes (specified by
.BR <what> )
by one or more requestors (specified by
.BR <who> ).
+
+.LP
+Lists of access directives are evaluated in the order they appear
+in \fIslapd.conf\fP.
+When a
+.B <what>
+clause matches the datum whose access is being evaluated, its
+.B <who>
+clause list is checked.
+When a
+.B <who>
+clause matches the accessor's properties, its
+.B <access>
+and
+.B <control>
+clauses are evaluated.
+Access control checking stops at the first match of the
+.B <what>
+and
+.B <who>
+clause, unless otherwise dictated by the
+.B <control>
+clause.
+Each
+.B <who>
+clause list is implicitly terminated by a
+.LP
+.nf
+ by * none stop
+.fi
+.LP
+clause that results in stopping the access control with no access
+privileges granted.
+Each
+.B <what>
+clause list is implicitly terminated by a
+.LP
+.nf
+ access to *
+ by * none
+.fi
+.LP
+clause that results in granting no access privileges to an otherwise
+unspecified datum.
.SH THE <WHAT> FIELD
The field
.BR <what>
It can have the forms
.LP
.nf
- *
- [dn[.<dnstyle>]=<DN>]
- [filter=<ldapfilter>]
- [attrs=<attrlist>]
+ dn[.<dnstyle>]=<dnpattern>
+ filter=<ldapfilter>
+ attrs=<attrlist>[ val[/matchingRule][.<attrstyle>]=<attrval>]
.fi
.LP
-The wildcard
-.B *
-stands for all the entries.
+with
+.LP
+.nf
+ <dnstyle>={{exact|base(object)}|regex
+ |one(level)|sub(tree)|children}
+ <attrlist>={<attr>|[{!|@}]<objectClass>}[,<attrlist>]
+ <attrstyle>={{exact|base(object)}|regex
+ |one(level)|sub(tree)|children}
+.fi
.LP
The statement
-.B dn=<DN>
+.B dn=<dnpattern>
selects the entries based on their naming context.
-The pattern is a string representation of the entry's DN.
-.BR base ,
+The
+.B <dnpattern>
+is a string representation of the entry's DN.
+The wildcard
+.B *
+stands for all the entries, and it is implied if no
+.B dn
+form is given.
+.LP
+The
+.B <dnstyle>
+is optional; however, it is recommended to specify it to avoid ambiguities.
+.B Base
+(synonym of
+.BR baseObject ),
the default,
or
.B exact
(an alias of
.BR base )
-indicates the entry whose DN is equal to the pattern.
+indicates the entry whose DN is equal to the
+.BR <dnpattern> ;
.B one
+(synonym of
+.BR onelevel )
indicates all the entries immediately below the
-.BR pattern ,
-.B subtree
-indicates all entries in the subtree at the pattern,
+.BR <dnpattern> ,
+.B sub
+(synonym of
+.BR subtree )
+indicates all entries in the subtree at the
+.BR <dnpattern> ,
.B children
-indicates all the entries below (subordinate to) the pattern.
+indicates all the entries below (subordinate to) the
+.BR <dnpattern> .
.LP
If the
.B <dnstyle>
qualifier is
.BR regex ,
-then the value is a regular expression pattern,
+then
+.B <dnpattern>
+is a POSIX (''extended'') regular expression pattern,
as detailed in
-.BR regex (7),
+.BR regex (7)
+and/or
+.BR 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.
.LP
The statement
.B filter=<ldapfilter>
-selects the entries based on a valid LDAP filter as described in RFC 2254.
+selects the entries based on a valid LDAP filter as described in RFC 4515.
+A filter of
+.B (objectClass=*)
+is implied if no
+.B filter
+form is given.
.LP
The statement
.B attrs=<attrlist>
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
+.B <attrlist>
+that are prefixed by
+.B @
+are directly treated as objectClass names. A name prefixed by
+.B !
+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
+.B attrs
+form is given,
+.B attrs=@extensibleObject
+is implied, i.e. all attributes are addressed.
.LP
Using the form
-.B attrs=<attr> val[.<style>]=<value>
+.B 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. A value
-.B <style>
-of
+In this case, only a single attribute type may be given. The
+.B <attrstyle>
.B exact
(the default) uses the attribute's equality matching rule to compare the
-value. If the
-.B <style>
+value, unless a different (and compatible) matching rule is specified. If the
+.B <attrstyle>
is
.BR regex ,
-the provided value is used as a regular expression pattern.
+the provided value is used as a POSIX (''extended'') regular
+expression pattern. If the attribute has DN syntax, the
+.B <attrstyle>
+can be any of
+.BR base ,
+.BR onelevel ,
+.B subtree
+or
+.BR children ,
+resulting in base, onelevel, subtree or children match, respectively.
.LP
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
+.B regex
+matching can be dereferenced in the
+.B <who>
+field using the syntax
+.IR ${v<n>} ,
+where
+.I <n>
+is the submatch number.
+The default syntax,
+.IR $<n> ,
+is actually an alias for
+.IR ${d<n>} ,
+that corresponds to dereferencing submatches from the
+.B dnpattern
+portion of the
+.B <what>
+field.
.SH THE <WHO> FIELD
The field
.B <who>
*
anonymous
users
- self
+ self[.<selfstyle>]
dn[.<dnstyle>[,<modifier>]]=<DN>
dnattr=<attrname>
+
+ realanonymous
+ realusers
+ realself[.<selfstyle>]
+
+ realdn[.<dnstyle>[,<modifier>]]=<DN>
+ realdnattr=<attrname>
+
group[/<objectclass>[/<attrname>]]
- [.<style>]=<group>
- peername[.<style>]=<peername>
+ [.<groupstyle>]=<group>
+ peername[.<peernamestyle>]=<peername>
sockname[.<style>]=<sockname>
domain[.<domainstyle>[,<modifier>]]=<domain>
sockurl[.<style>]=<sockurl>
- set[.<style>]=<pattern>
+ set[.<setstyle>]=<pattern>
ssf=<n>
transport_ssf=<n>
tls_ssf=<n>
sasl_ssf=<n>
- aci=<attrname>
+ dynacl/<name>[/<options>][.<dynstyle>][=<pattern>]
+.fi
+.LP
+with
+.LP
+.nf
+ <style>={exact|regex|expand}
+ <selfstyle>={level{<n>}}
+ <dnstyle>={{exact|base(object)}|regex
+ |one(level)|sub(tree)|children|level{<n>}}
+ <groupstyle>={exact|expand}
+ <peernamestyle>={<style>|ip|ipv6|path}
+ <domainstyle>={exact|regex|sub(tree)}
+ <setstyle>={exact|expand}
+ <modifier>={expand}
+ <name>=aci <pattern>=<attrname>]
.fi
.LP
They may be specified in combination.
.B *
refers to everybody.
.LP
+The keywords prefixed by
+.B real
+act as their counterparts without prefix; the checking respectively occurs
+with the \fIauthentication\fP DN and the \fIauthorization\fP DN.
+.LP
The keyword
.B anonymous
means access is granted to unauthenticated clients; it is mostly used
.B 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
+.B level{<n>}
+style, where \fI<n>\fP 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 "\fIby self.level{1} ...\fP" clause would match
+when the object "\fIdc=example,dc=com\fP" is accessed
+by "\fIcn=User,dc=example,dc=com\fP".
+A "\fIby self.level{-1} ...\fP" clause would match when the same user
+accesses the object "\fIou=Address Book,cn=User,dc=example,dc=com\fP".
.LP
The statement
.B dn=<DN>
.BR $<digit> ,
with
.B digit
-ranging from 1 to 9.
+ranging from 0 to 9 (where 0 matches the entire string),
+or the form
+.BR ${<digit>+} ,
+for submatches higher than 9.
+Substring substitution from attribute value can
+be done in
+using the form
+.BR ${v<digit>+} .
+Since the dollar character is used to indicate a substring replacement,
+the dollar character that is used to indicate match up to the end of
+the string must be escaped by a second dollar character, e.g.
+.LP
+.nf
+ access to dn.regex="^(.+,)?uid=([^,]+),dc=[^,]+,dc=com$"
+ by dn.regex="^uid=$2,dc=[^,]+,dc=com$$" write
+.fi
+.LP
The style qualifier
allows an optional
.BR modifier .
.B dnstyle
is not
.BR regex .
+Note that the
+.B regex
+dnstyle in the above example may be of use only if the
+.B <by>
+clause needs to be a regex; otherwise, if the
+value of the second (from the right)
+.B dc=
+portion of the DN in the above example were fixed, the form
+.LP
+.nf
+ access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
+ by dn.exact,expand="uid=$2,dc=example,dc=com" write
+.fi
+.LP
+could be used; if it had to match the value in the
+.B <what>
+clause, the form
+.LP
+.nf
+ access to dn.regex="^(.+,)?uid=([^,]+),dc=([^,]+),dc=com$"
+ by dn.exact,expand="uid=$2,dc=$3,dc=com" write
+.fi
+.LP
+could be used.
+.LP
+Forms of the
+.B <what>
+clause other than regex may provide submatches as well.
+The
+.BR base(object) ,
+the
+.BR sub(tree) ,
+the
+.BR one(level) ,
+and the
+.BR children
+forms provide
+.B $0
+as the match of the entire string.
+The
+.BR sub(tree) ,
+the
+.BR one(level) ,
+and the
+.BR children
+forms also provide
+.B $1
+as the match of the rightmost part of the DN as defined in the
+.B <what>
+clause.
+This may be useful, for instance, to provide access to all the
+ancestors of a user by defining
+.LP
+.nf
+ access to dn.subtree="dc=com"
+ by dn.subtree,expand="$1" read
+.fi
+.LP
+which means that only access to entries that appear in the DN of the
+.B <by>
+clause is allowed.
+.LP
+The
+.BR level{<n>}
+form is an extension and a generalization of the
+.BR onelevel
+form, which matches all DNs whose <n>-th ancestor is the pattern.
+So, \fIlevel{1}\fP is equivalent to \fIonelevel\fP,
+and \fIlevel{0}\fP is equivalent to \fIbase\fP.
+.LP
+It is perfectly useless to give any access privileges to a DN
+that exactly matches the
+.B 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
+.BR rootdn ,
+to solve the intrinsic chicken-and-egg problem.
.LP
The statement
.B dnattr=<attrname>
and
.B <attrname>
define the objectClass and the member attributeType of the group entry.
+The defaults are
+.B groupOfNames
+and
+.BR member ,
+respectively.
The optional style qualifier
.B <style>
can be
-.BR regex ,
+.BR expand ,
which means that
.B <group>
will be expanded as a replacement string (but not as a regular expression)
-according to regex (7), and
-.B base
-or
-.B exact
-(an alias of
-.BR base ),
+according to
+.BR regex (7)
+and/or
+.BR re_format (7),
+and
+.BR exact ,
which means that exact match will be used.
+If the style of the DN portion of the
+.B <what>
+clause is regex, the submatches are made available according to
+.BR regex (7)
+and/or
+.BR re_format (7);
+other styles provide limited submatches as discussed above about
+the DN form of the
+.B <by>
+clause.
.LP
For static groups, the specified attributeType must have
.B DistinguishedName
.B labeledURI
attributeType. Only LDAP URIs of the form
.B ldap:///<base>??<scope>?<filter>
-will be evaluated in a dynamic group.
+will be evaluated in a dynamic group, by searching the local server only.
.LP
The statements
.BR peername=<peername> ,
.BR domain=<domain> ,
and
.BR sockurl=<sockurl>
-mean that the contacting host IP for
+mean that the contacting host IP (in the form
+.BR "IP=<ip>:<port>"
+for IPv4, or
+.BR "IP=[<ipv6>]:<port>"
+for IPv6)
+or the contacting host named pipe file name (in the form
+.B "PATH=<path>"
+if connecting through a named pipe) for
.BR peername ,
the named pipe file name for
.BR sockname ,
.B style
rules for pattern match described for the
.B group
-case apply.
+case apply, plus the
+.B regex
+style, which implies submatch
+.B expand
+and regex match of the corresponding connection parameters.
The
-.BR domain
+.B exact
+style of the
+.BR <peername>
+clause (the default) implies a case-exact match on the client's
+.BR IP ,
+including the
+.B "IP="
+prefix and the trailing
+.BR ":<port>" ,
+or the client's
+.BR path ,
+including the
+.B "PATH="
+prefix if connecting through a named pipe.
+The special
+.B ip
+style interprets the pattern as
+.BR <peername>=<ip>[%<mask>][{<n>}] ,
+where
+.B <ip>
+and
+.B <mask>
+are dotted digit representations of the IP and the mask, while
+.BR <n> ,
+delimited by curly brackets, is an optional port.
+The same applies to IPv6 addresses when the special
+.B ipv6
+style is used.
+When checking access privileges, the IP portion of the
+.BR peername
+is extracted, eliminating the
+.B "IP="
+prefix and the
+.B ":<port>"
+part, and it is compared against the
+.B <ip>
+portion of the pattern after masking with
+.BR <mask> :
+\fI((peername & <mask>) == <ip>)\fP.
+As an example,
+.B peername.ip=127.0.0.1
+and
+.B peername.ipv6=::1
+allow connections only from localhost,
+.B peername.ip=192.168.1.0%255.255.255.0
+allows connections from any IP in the 192.168.1 class C domain, and
+.B peername.ip=192.168.1.16%255.255.255.240{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
+.B path
+style eliminates the
+.B "PATH="
+prefix from the
+.B peername
+when connecting through a named pipe, and performs an exact match
+on the given pattern.
+The
+.BR <domain>
clause also allows the
.B subtree
style, which succeeds when a fully qualified name exactly matches the
exactly matches the
.BR domain
pattern.
+The
+.B expand
+style is allowed, implying an
+.B exact
+match with submatch expansion; the use of
+.B expand
+as a style modifier is considered more appropriate.
+As an example,
+.B domain.subtree=example.com
+will match www.example.com, but will not match www.anotherexample.com.
The
.B domain
of the contacting host is determined by performing a DNS reverse lookup.
The optional
.B domainstyle
qualifier of the
-.B domain
+.B <domain>
clause allows a
.B modifier
option; the only value currently supported is
is not
.BR regex ,
much like the analogous usage in
-.B dn
+.B <dn>
clause.
.LP
The statement
is undocumented yet.
.LP
The statement
-.B aci=<attrname>
+.B dynacl/<name>[/<options>][.<dynstyle>][=<pattern>]
+means that access checking is delegated to the admin-defined method
+indicated by
+.BR <name> ,
+which can be registered at run-time by means of the
+.B moduleload
+statement.
+The fields
+.BR <options> ,
+.B <dynstyle>
+and
+.B <pattern>
+are optional, and are directly passed to the registered parsing routine.
+Dynacl is experimental; it must be enabled at compile time.
+.LP
+The statement
+.B dynacl/aci[=<attrname>]
means that the access control is determined by the values in the
.B attrname
of the entry itself.
+The optional
+.B <attrname>
+indicates what attributeType holds the ACI information in the entry.
+By default, the
+.B OpenLDAPaci
+operational attribute is used.
ACIs are experimental; they must be enabled at compile time.
.LP
The statements
.BR tls_ssf=<n> ,
and
.BR sasl_ssf=<n>
-set the required Security Strength Factor (ssf) required to grant access.
+set the minimum required Security Strength Factor (ssf) needed
+to grant access. The value should be positive integer.
.SH THE <ACCESS> FIELD
-The field
-.B <access> ::= [self]{<level>|<priv>}
+The optional field
+.B <access> ::= [[real]self]{<level>|<priv>}
determines the access level or the specific access privileges the
.B who
field will have.
Its component are defined as
.LP
.nf
- <level> ::= none|auth|compare|search|read|write
- <priv> ::= {=|+|-}{w|r|s|c|x}+
+ <level> ::= none|disclose|auth|compare|search|read|{write|add|delete}|manage
+ <priv> ::= {=|+|\-}{0|d|x|c|s|r|{w|a|z}|m}+
.fi
.LP
The modifier
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 bound.
+It implies the user that requests access is authorized.
+The modifier
+.B realself
+refers to the authenticated DN as opposed to the authorized DN of the
+.B self
+modifier.
An example is the
.B 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, without affecting other members.
+its own DN from the member list of a group, while being not allowed
+to affect other members.
.LP
The
.B level
privileges.
The possible levels are
.BR none ,
+.BR disclose ,
.BR auth ,
.BR compare ,
.BR search ,
.BR read ,
+.BR write ,
and
-.BR write .
+.BR manage .
Each access level implies all the preceding ones, thus
-.B write
-access will imply all accesses.
-While
-.B none
-is trivial,
+.B manage
+grants all access including administrative access.
+The
+.BR write
+access is actually the combination of
+.BR add
+and
+.BR delete ,
+which respectively restrict the write privilege to add or delete
+the specified
+.BR <what> .
+
+.LP
+The
+.B none
+access level disallows all access including disclosure on error.
+.LP
+The
+.B disclose
+access level allows disclosure of information on error.
+.LP
+The
.B auth
-access means that one is allowed access to an attribute to perform
+access level means that one is allowed access to an attribute to perform
authentication/authorization operations (e.g.
.BR bind )
with no other access.
The
.B +
and
-.B -
+.B \-
signs add/remove access privileges to the existing ones.
The privileges are
+.B m
+for manage,
.B w
for write,
+.B a
+for add,
+.B z
+for delete,
.B r
for read,
.B s
for search,
.B c
-for compare, and
+for compare,
.B x
-for authentication.
-More than one privilege can be added in one statement.
+for authentication, and
+.B d
+for disclose.
+More than one of the above privileges can be added in one statement.
+.B 0
+indicates no privileges and is used only by itself (e.g., +0).
+Note that
+.B +az
+is equivalent to
+.BR +w .
.LP
+If no access is given, it defaults to
+.BR +0 .
+.SH THE <CONTROL> FIELD
The optional field
.B <control>
controls the flow of access rule application.
.LP
which grants everybody search and compare privileges, and adds read
privileges to authenticated clients.
+.LP
+One useful application is to easily grant write privileges to an
+.B updatedn
+that is different from the
+.BR rootdn .
+In this case, since the
+.B updatedn
+needs write access to (almost) all data, one can use
+.LP
+.nf
+ access to *
+ by dn.exact="cn=The Update DN,dc=example,dc=com" write
+ by * break
+.fi
+.LP
+as the first access rule.
+As a consequence, unless the operation is performed with the
+.B updatedn
+identity, control is passed straight to the subsequent rules.
+
.SH OPERATION REQUIREMENTS
Operations require different privileges on different portions of entries.
-.TP
+The following summary applies to primary database backends such as
+the BDB and HDB backends. Requirements for other backends may
+(and often do) differ.
+
+.LP
The
.B add
-operation requires
-.B write
-privileges on the meta-attribute
+operation requires
+.B add (=a)
+privileges on the pseudo-attribute
.B entry
of the entry being added, and
-.B write
-privileges on the meta-attribute
+.B add (=a)
+privileges on the pseudo-attribute
.B children
of the entry's parent.
-.TP
+When adding the suffix entry of a database,
+.B add
+access to
+.B children
+of the empty DN ("") is required. Also if
+Add content ACL checking has been configured on
+the database (see the
+.BR slapd.conf (5)
+or
+.BR slapd\-config (5)
+manual page),
+.B add (=a)
+will be required on all of the attributes being added.
+
+.LP
The
.B bind
operation, when credentials are stored in the directory, requires
-.B auth
+.B auth (=x)
privileges on the attribute the credentials are stored in (usually
.BR userPassword ).
-.TP
+
+.LP
The
.B compare
operation requires
-.B compare
+.B compare (=c)
privileges on the attribute that is being compared.
-.B FIXME: should it require also compare privileges on the entry's meta-attribute?
-.TP
+
+.LP
The
.B delete
operation requires
-.B write
-privileges on the meta-attribute
+.B delete (=z)
+privileges on the pseudo-attribute
.B entry
of the entry being deleted, and
-.B write
+.B delete (=d)
privileges on the
.B children
-meta-attribute of the entry's parent.
-.TP
+pseudo-attribute of the entry's parent.
+
+.LP
The
.B modify
operation requires
-.B write
-privileges on the attibutes being modified.
-.TP
+.B write (=w)
+privileges on the attributes being modified.
+In detail,
+.B add (=a)
+is required to add new values,
+.B delete (=z)
+is required to delete existing values,
+and both
+.B delete
+and
+.BR "add (=az)" ,
+or
+.BR "write (=w)" ,
+are required to replace existing values.
+
+.LP
The
.B modrdn
operation requires
-.B write
-privileges on the meta-attribute
+.B write (=w)
+privileges on the pseudo-attribute
.B entry
of the entry whose relative DN is being modified,
-.B write
-privileges on the meta-attribute
+.B delete (=z)
+privileges on the pseudo-attribute
+.B children
+of the old entry's parents,
+.B add (=a)
+privileges on the pseudo-attribute
.B children
-of the old and new entry's parents, and
-.B write
+of the new entry's parents, and
+.B add (=a)
privileges on the attributes that are present in the new relative DN.
-.B Write
+.B Delete (=z)
privileges are also required on the attributes that are present
in the old relative DN if
.B deleteoldrdn
is set to 1.
-.TP
+
+.LP
The
.B search
-operation, for each entry, requires
-.B search
+operation, requires
+.B search (=s)
+privileges on the
+.B entry
+pseudo-attribute of the searchBase
+(NOTE: this was introduced with OpenLDAP 2.4).
+Then, for each entry, it requires
+.B search (=s)
privileges on the attributes that are defined in the filter.
-Then, the resulting entries are tested for
-.B read
-privileges on the meta-attribute
+The resulting entries are finally tested for
+.B read (=r)
+privileges on the pseudo-attribute
.B entry
+(for read access to the entry itself)
and for
-.B read
+.B read (=r)
access on each value of each attribute that is requested.
-.B Referrals
-are also checked for
-.B read
-access on the meta-attribute
-.BR entry .
+Also, for each
+.B referral
+object used in generating continuation references, the operation requires
+.B read (=r)
+access on the pseudo-attribute
+.B entry
+(for read access to the referral object itself),
+as well as
+.B read (=r)
+access to the attribute holding the referral information
+(generally the
+.B ref
+attribute).
+
+.LP
+Some internal operations and some
+.B controls
+require specific access privileges.
+The
+.B authzID
+mapping and the
+.B proxyAuthz
+control require
+.B 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
+.B authz-regexp
+directives).
+.B Auth (=x)
+privileges are also required on the
+.B authzTo
+attribute of the authorizing identity and/or on the
+.B 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
+.BR auth .
+
+.LP
+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.
+.BR back\-bdb (5),
+and
+.BR back\-hdb (5).
+
+Some other backend, like
+.BR 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.
+
.SH CAVEATS
It is strongly recommended to explicitly use the most appropriate
-DN
-.BR style ,
-to avoid possible incorrect specifications of the access rules as well
-as for performance (avoid unrequired regex matching when an exact
+.B <dnstyle>
+in
+.B <what>
+and
+.B <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.
.LP
-An adminisistrator might create a rule of the form:
+An administrator might create a rule of the form:
.LP
.nf
access to dn.regex="dc=example,dc=com"
written:
.LP
.nf
- access to dn.regex="^(.+,)?dc=example,dc=com$$"
+ access to dn.regex="^(.+,)?dc=example,dc=com$"
by ...
.fi
.LP
by ...
.fi
.LP
+When writing submatch rules, it may be convenient to avoid unnecessary
+.B regex
+.B <dnstyle>
+use; for instance, to allow access to the subtree of the user
+that matches the
+.B <what>
+clause, one could use
+.LP
+.nf
+ access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
+ by dn.regex="^uid=$2,dc=example,dc=com$$" write
+ by ...
+.fi
+.LP
+However, since all that is required in the
+.B <by>
+clause is substring expansion, a more efficient solution is
+.LP
+.nf
+ access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
+ by dn.exact,expand="uid=$2,dc=example,dc=com" write
+ by ...
+.fi
+.LP
+In fact, while a
+.B <dnstyle>
+of
+.B regex
+implies substring expansion,
+.BR exact ,
+as well as all the other DN specific
+.B <dnstyle>
+values, does not, so it must be explicitly requested.
+.LP
.SH FILES
.TP
ETCDIR/slapd.conf
default slapd configuration file
.SH SEE ALSO
.BR slapd (8),
+.BR slapd\-* (5),
+.BR slapacl (8),
+.BR regex (7),
+.BR re_format (7)
.LP
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
.SH ACKNOWLEDGEMENTS
-.B OpenLDAP
-is developed and maintained by The OpenLDAP Project (http://www.openldap.org/).
-.B OpenLDAP
-is derived from University of Michigan LDAP 3.3 Release.
+.so ../Project