Apache HTTP Server Version 2.4 (original) (raw)

Apache Module mod_authz_core

Available Languages: en | fr

Summary

This module provides core authorization capabilities so that authenticated users can be allowed or denied access to portions of the web site. [mod_authz_core](../mod/mod%5Fauthz%5Fcore.html) provides the functionality to register various authorization providers. It is usually used in conjunction with an authentication provider module such as [mod_authn_file](../mod/mod%5Fauthn%5Ffile.html) and an authorization module such as [mod_authz_user](../mod/mod%5Fauthz%5Fuser.html). It also allows for advanced logic to be applied to the authorization processing.

Authorization Containers

The authorization container directives[<RequireAll>](#requireall),[<RequireAny>](#requireany) and[<RequireNone>](#requirenone) may be combined with each other and with the[Require](#require) directive to express complex authorization logic.

The example below expresses the following authorization logic. In order to access the resource, the user must either be thesuperadmin user, or belong to both theadmins group and the Administrators LDAP group and either belong to the sales group or have the LDAP dept attribute sales. Furthermore, in order to access the resource, the user must not belong to either the temps group or the LDAP group Temporary Employees.

<Directory "/www/mydocs"> Require user superadmin Require group admins Require ldap-group "cn=Administrators,o=Airius" Require group sales Require ldap-attribute dept="sales" Require group temps Require ldap-group "cn=Temporary Employees,o=Airius"

The Require Directives

[mod_authz_core](../mod/mod%5Fauthz%5Fcore.html) provides some generic authorization providers which can be used with the[Require](#require) directive.

Require env

The env provider allows access to the server to be controlled based on the existence of an environment variable. When Require env env-variable is specified, then the request is allowed access if the environment variable env-variable exists. The server provides the ability to set environment variables in a flexible way based on characteristics of the client request using the directives provided by[mod_setenvif](../mod/mod%5Fsetenvif.html). Therefore, this directive can be used to allow access based on such factors as the clientsUser-Agent (browser type), Referer, or other HTTP request header fields.

SetEnvIf User-Agent "^KnockKnock/2.0" let_me_in <Directory "/docroot"> Require env let_me_in

In this case, browsers with a user-agent string beginning with KnockKnock/2.0 will be allowed access, and all others will be denied.

When the server looks up a path via an internalsubrequest such as looking for a [DirectoryIndex](../mod/mod%5Fdir.html#directoryindex) or generating a directory listing with [mod_autoindex](../mod/mod%5Fautoindex.html), per-request environment variables are not inherited in the subrequest. Additionally,[SetEnvIf](../mod/mod%5Fsetenvif.html#setenvif) directives are not separately evaluated in the subrequest due to the API phases[mod_setenvif](../mod/mod%5Fsetenvif.html) takes action in.

Require all

The all provider mimics the functionality that was previously provided by the 'Allow from all' and 'Deny from all' directives. This provider can take one of two arguments which are 'granted' or 'denied'. The following examples will grant or deny access to all requests.

Require all granted

Require all denied

Require method

The method provider allows using the HTTP method in authorization decisions. The GET and HEAD methods are treated as equivalent. The TRACE method is not available to this provider, use [TraceEnable](../mod/core.html#traceenable) instead.

The following example will only allow GET, HEAD, POST, and OPTIONS requests:

Require method GET POST OPTIONS

The following example will allow GET, HEAD, POST, and OPTIONS requests without authentication, and require a valid user for all other methods:

Require expr

The expr provider allows basing authorization decisions on arbitrary expressions.

Require expr "%{TIME_HOUR} -ge 9 && %{TIME_HOUR} -le 17"

Require expr "!(%{QUERY_STRING} =~ /secret/) && %{REQUEST_URI} in { '/example.cgi', '/other.cgi' }"

The syntax is described in the ap_expr documentation. Before httpd 2.4.16, the surrounding double-quotes MUST be omitted.

Normally, the expression is evaluated before authentication. However, if the expression returns false and references the variable%{REMOTE_USER}, authentication will be performed and the expression will be re-evaluated.

Creating Authorization Provider Aliases

Extended authorization providers can be created within the configuration file and assigned an alias name. The alias providers can then be referenced through the [Require](#require) directive in the same way as a base authorization provider. Besides the ability to create and alias an extended provider, it also allows the same extended authorization provider to be referenced by multiple locations.

Example

The example below creates two different ldap authorization provider aliases based on the ldap-group authorization provider. This example allows a single authorization location to check group membership within multiple ldap hosts:

<AuthzProviderAlias ldap-group ldap-group-alias1 "cn=my-group,o=ctx"> AuthLDAPBindDN "cn=youruser,o=ctx" AuthLDAPBindPassword yourpassword AuthLDAPUrl "ldap://ldap.host/o=ctx"

<AuthzProviderAlias ldap-group ldap-group-alias2 "cn=my-other-group,o=dev"> AuthLDAPBindDN "cn=yourotheruser,o=dev" AuthLDAPBindPassword yourotherpassword AuthLDAPUrl "ldap://other.ldap.host/o=dev?cn"

Alias "/secure" "/webpages/secure" <Directory "/webpages/secure"> Require all granted

AuthBasicProvider file

AuthType Basic
AuthName LDAP_Protected_Place

#implied OR operation
Require ldap-group-alias1
Require ldap-group-alias2

AuthMerging Directive

When authorization is enabled, it is normally inherited by each subsequent configuration section, unless a different set of authorization directives is specified. This is the default action, which corresponds to an explicit setting of AuthMerging Off.

However, there may be circumstances in which it is desirable for a configuration section's authorization to be combined with that of its predecessor while configuration sections are being merged. Two options are available for this case, And and Or.

When a configuration section contains AuthMerging And or AuthMerging Or, its authorization logic is combined with that of the nearest predecessor (according to the overall order of configuration sections) which also contains authorization logic as if the two sections were jointly contained within a[<RequireAll>](#requireall) or[<RequireAny>](#requireany) directive, respectively.

The setting of AuthMerging is not inherited outside of the configuration section in which it appears. In the following example, only users belonging to group alpha may access /www/docs. Users belonging to either groups alpha or beta may access/www/docs/ab. However, the default Off setting of AuthMerging applies to the[<Directory>](../mod/core.html#directory) configuration section for /www/docs/ab/gamma, so that section's authorization directives override those of the preceding sections. Thus only users belong to the groupgamma may access /www/docs/ab/gamma.

<Directory "/www/docs"> AuthType Basic AuthName Documents AuthBasicProvider file AuthUserFile "/usr/local/apache/passwd/passwords" Require group alpha

<Directory "/www/docs/ab"> AuthMerging Or Require group beta

<Directory "/www/docs/ab/gamma"> Require group gamma

Directive

<AuthzProviderAlias> and</AuthzProviderAlias> are used to enclose a group of authorization directives that can be referenced by the alias name using the directive [Require](#require).

If several parameters are needed in Require-Parameters, they must be enclosed in quotation marks. Otherwise, only the first one is taken into account.

In this example, for both addresses to be taken into account, they MUST be enclosed

between quotation marks

<AuthzProviderAlias ip reject-ips "XXX.XXX.XXX.XXX YYY.YYY.YYY.YYY">

<Directory "/path/to/dir"> Require not reject-ips Require all granted

AuthzSendForbiddenOnFailure Directive

If authentication succeeds but authorization fails, Apache HTTPD will respond with an HTTP response code of '401 UNAUTHORIZED' by default. This usually causes browsers to display the password dialogue to the user again, which is not wanted in all situations.AuthzSendForbiddenOnFailure allows to change the response code to '403 FORBIDDEN'.

Security Warning

Modifying the response in case of missing authorization weakens the security of the password, because it reveals to a possible attacker, that his guessed password was right.

Require Directive

This directive tests whether an authenticated user is authorized according to a particular authorization provider and the specified restrictions. [mod_authz_core](../mod/mod%5Fauthz%5Fcore.html) provides the following generic authorization providers:

Require all granted

Access is allowed unconditionally.

Require all denied

Access is denied unconditionally.

Require env env-var [env-var] ...

Access is allowed only if one of the given environment variables is set.

Require method http-method [http-method] ...

Access is allowed only for the given HTTP methods.

Require expr expression

Access is allowed if expression evaluates to true.

Some of the allowed syntaxes provided by [mod_authz_user](../mod/mod%5Fauthz%5Fuser.html),[mod_authz_host](../mod/mod%5Fauthz%5Fhost.html), and [mod_authz_groupfile](../mod/mod%5Fauthz%5Fgroupfile.html) are:

Require user userid [userid] ...

Only the named users can access the resource.

Require group group-name [group-name] ...

Only users in the named groups can access the resource.

Require valid-user

All valid users can access the resource.

Require ip 10 172.20 192.168.2

Clients in the specified IP address ranges can access the resource.

Require forward-dns dynamic.example.org

A client the IP of which is resolved from the name dynamic.example.org will be granted access.

Other authorization modules that implement require options include [mod_authnz_ldap](../mod/mod%5Fauthnz%5Fldap.html),[mod_authz_dbm](../mod/mod%5Fauthz%5Fdbm.html), [mod_authz_dbd](../mod/mod%5Fauthz%5Fdbd.html),[mod_authz_owner](../mod/mod%5Fauthz%5Fowner.html) and [mod_ssl](../mod/mod%5Fssl.html).

In most cases, for a complete authentication and authorization configuration, Require must be accompanied by[AuthName](../mod/mod%5Fauthn%5Fcore.html#authname), [AuthType](../mod/mod%5Fauthn%5Fcore.html#authtype) and[AuthBasicProvider](../mod/mod%5Fauth%5Fbasic.html#authbasicprovider) or[AuthDigestProvider](../mod/mod%5Fauth%5Fdigest.html#authdigestprovider) directives, and directives such as[AuthUserFile](../mod/mod%5Fauthn%5Ffile.html#authuserfile) and [AuthGroupFile](../mod/mod%5Fauthz%5Fgroupfile.html#authgroupfile) (to define users and groups) in order to work correctly. Example:

AuthType Basic AuthName "Restricted Resource" AuthBasicProvider file AuthUserFile "/web/users" AuthGroupFile "/web/groups" Require group admin

Access controls which are applied in this way are effective forall methods. This is what is normally desired. If you wish to apply access controls only to specific methods, while leaving other methods unprotected, then place the Require statement into a[<Limit>](../mod/core.html#limit) section.

The result of the Require directive may be negated through the use of thenot option. As with the other negated authorization directive <RequireNone>, when the Require directive is negated it can only fail or return a neutral result, and therefore may never independently authorize a request.

In the following example, all users in the alpha and beta groups are authorized, except for those who are also in the reject group.

<Directory "/www/docs"> Require group alpha beta Require not group reject

When multiple Require directives are used in a singleconfiguration section and are not contained in another authorization directive like[<RequireAll>](#requireall), they are implicitly contained within a[<RequireAny>](#requireany) directive. Thus the first one to authorize a user authorizes the entire request, and subsequent Require directives are ignored.

Security Warning

Exercise caution when setting authorization directives in[Location](../mod/core.html#location) sections that overlap with content served out of the filesystem. By default, these configuration sections overwrite authorization configuration in [Directory](../mod/core.html#directory), and [Files](../mod/core.html#files) sections.

The [AuthMerging](#authmerging) directive can be used to control how authorization configuration sections are merged.

See also

• Access Control howto
• Authorization Containers
• [mod_authn_core](../mod/mod%5Fauthn%5Fcore.html)
• [mod_authz_host](../mod/mod%5Fauthz%5Fhost.html)

Directive

<RequireAll> and</RequireAll> are used to enclose a group of authorization directives of which none must fail and at least one must succeed in order for the <RequireAll> directive to succeed.

If none of the directives contained within the<RequireAll> directive fails, and at least one succeeds, then the<RequireAll> directive succeeds. If none succeed and none fail, then it returns a neutral result. In all other cases, it fails.

See also

• Authorization Containers
• Authentication, Authorization, and Access Control

Directive

<RequireAny> and</RequireAny> are used to enclose a group of authorization directives of which one must succeed in order for the <RequireAny> directive to succeed.

If one or more of the directives contained within the<RequireAny> directive succeed, then the <RequireAny> directive succeeds. If none succeed and none fail, then it returns a neutral result. In all other cases, it fails.

Because negated authorization directives are unable to return a successful result, they can not significantly influence the result of a <RequireAny> directive. (At most they could cause the directive to fail in the case where they failed and all other directives returned a neutral value.) Therefore negated authorization directives are not permitted within a <RequireAny> directive.

See also

• Authorization Containers
• Authentication, Authorization, and Access Control

Directive

<RequireNone> and</RequireNone> are used to enclose a group of authorization directives of which none must succeed in order for the<RequireNone> directive to not fail.

If one or more of the directives contained within the<RequireNone> directive succeed, then the <RequireNone> directive fails. In all other cases, it returns a neutral result. Thus as with the other negated authorization directive Require not, it can never independently authorize a request because it can never return a successful result. It can be used, however, to restrict the set of users who are authorized to access a resource.

Because negated authorization directives are unable to return a successful result, they can not significantly influence the result of a <RequireNone> directive. Therefore negated authorization directives are not permitted within a<RequireNone> directive.

See also

• Authorization Containers
• Authentication, Authorization, and Access Control