slapd.access.5

ldap服务器源码

.TH SLAPD.ACCESS 5 "RELEASEDATE" "OpenLDAP LDVERSION"
.\" Copyright 1998-2007 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
.\" $OpenLDAP: pkg/ldap/doc/man/man5/slapd.access.5,v 1.55.2.10 2007/01/02 21:43:45 kurt Exp $
.SH NAME
slapd.access \- access configuration for slapd, the stand-alone LDAP daemon
.SH SYNOPSIS
ETCDIR/slapd.conf
.SH DESCRIPTION
The 
.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
.BR slapacl (8),
.BR slapadd (8),
.BR slapauth (8),
.BR slapcat (8),
.BR slapdn (8),
.BR slapindex (8),
and
.BR slaptest (8).
.LP
The
.B slapd.conf
file consists of a series of global configuration options that apply to
.B slapd
as a whole (including all backends), followed by zero or more database
backend definitions that contain information specific to a backend
instance.
.LP
The general format of
.B slapd.conf
is as follows:
.LP
.nf
    # 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
    ...
.fi
.LP
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.
.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").
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.
.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> ] ]+"
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> ).
.SH THE <WHAT> FIELD
The field
.BR <what>
specifies the entity the access control directive applies to.
It can have the forms
.LP
.nf
	dn[.<dnstyle>]=<dnpattern>
	filter=<ldapfilter>
	attrs=<attrlist>[ val[/matchingRule][.<attrstyle>]=<attrval>]
.fi
.LP
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=<dnpattern>
selects the entries based on their naming context.
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
.BR <dnpattern> ;
.B one
(synonym of
.BR onelevel )
indicates all the entries immediately below the
.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 
.BR <dnpattern> .
.LP
If the
.B <dnstyle>
qualifier is
.BR regex ,
then 
.B <dnpattern>
is a POSIX (''extended'') regular expression pattern,
as detailed in
.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.
A filter of
.B (objectClass=*)
is implied if no
.B filter
form is given.
.LP
The statement
.B attrs=<attrlist>
selects the attributes the access control rule applies to.
It is a comma-separated list of attribute types, plus the special names
.BR entry ,
indicating access to the entry itself, and
.BR 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 
.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[/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
.B <attrstyle>
.B 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
.B <attrstyle>
is
.BR regex ,
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.
.SH THE <WHO> FIELD
The field
.B <who>
indicates whom the access rules apply to.
Multiple 
.B <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
.LP
.nf
	*
	anonymous
	users
	self[.<selfstyle>]

	dn[.<dnstyle>[,<modifier>]]=<DN>
	dnattr=<attrname>

	realanonymous
	realusers
	realself[.<selfstyle>]

	realdn[.<dnstyle>[,<modifier>]]=<DN>
	realdnattr=<attrname>

	group[/<objectclass>[/<attrname>]]
		[.<groupstyle>]=<group>
	peername[.<peernamestyle>]=<peername>
	sockname[.<style>]=<sockname>
	domain[.<domainstyle>[,<modifier>]]=<domain>
	sockurl[.<style>]=<sockurl>
	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|path}
	<domainstyle>={exact|regex|sub(tree)}
	<setstyle>={exact|regex}
	<modifier>={expand}
.fi
.LP
They may be specified in combination.
.LP
.nf
.fi
.LP
The wildcard
.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 
to limit access to authentication resources (e.g. the
.B userPassword
attribute) to unauthenticated clients for authentication purposes.
.LP
The keyword
.B users
means access is granted to authenticated clients.
.LP
The keyword
.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>
means that access is granted to the matching DN.
The optional style qualifier
.B dnstyle
allows the same choices of the dn form of the
.B <what>
field.  In addition, the
.B regex
style can exploit substring substitution of submatches in the
.B <what>
dn.regex clause by using the form
.BR $<digit> ,
with 
.B digit
ranging from 0 to 9 (where 0 matches the entire string),
or the form
.BR ${<digit>+} ,
for submatches higher than 9.
Since the dollar character is used to indicate a substring replacement,
the dollar character that is used to indicate match up to the end of
the string must be escaped by a second dollar character, e.g.
.LP
.nf
    access to dn.regex="^(.+,)?uid=([^,]+),dc=[^,]+,dc=com$"
        by dn.regex="^uid=$2,dc=[^,]+,dc=com$$" write
.fi
.LP
The style qualifier
allows an optional
.BR modifier .
At present, the only type allowed is 
.BR expand ,
which causes substring substitution of submatches to take place
even if 
.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>
means that access is granted to requests whose DN is listed in the
entry being accessed under the 
.B <attrname>
attribute.
.LP
The statement
.B group=<group>
means that access is granted to requests whose DN is listed
in the group entry whose DN is given by
.BR <group> .
The optional parameters
.B <objectclass>
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 expand ,
which means that
.B <group>
will be expanded as a replacement string (but not as a regular expression)
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
or
.B NameAndOptionalUID
syntax. For dynamic groups the attributeType must
be a subtype of the
.B labeledURI
attributeType. Only LDAP URIs of the form
.B ldap:///<base>??<scope>?<filter>
will be evaluated in a dynamic group, by searching the local server only.
.LP
The statements
.BR peername=<peername> ,
.BR sockname=<sockname> ,
.BR domain=<domain> ,
and
.BR sockurl=<sockurl>
mean that the contacting host IP (in the form 
.BR "IP=<ip>:<port>" )
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 ,
the contacting host name for
.BR domain ,
and the contacting URL for
.BR sockurl
are compared against
.B pattern
to determine access.
The same
.B style
rules for pattern match described for the
.B group
case apply, plus the
.B regex
style, which implies submatch
.B expand
and regex match of the corresponding connection parameters.
The
.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.