spring-security/docs/manual/src/docbook/appendix-namespace.xml

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<?xml version="1.0" encoding="UTF-8"?>
<appendix version="5.0" xml:id="appendix-namespace" xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude">
<info>
<title>The Security Namespace</title>
</info>
<para> This appendix provides a reference to the elements available in the security namespace
and information on the underlying beans they create (a knowledge of the individual classes
and how they work together is assumed - you can find more information in the project Javadoc
and elsewhere in this document). If you haven't used the namespace before, please read the
<link xlink:href="#ns-config">introductory chapter</link> on namespace configuration, as
this is intended as a supplement to the information there. Using a good quality XML editor
while editing a configuration based on the schema is recommended as this will provide
contextual information on which elements and attributes are available as well as comments
explaining their purpose. The namespace is written in <link
xlink:href="http://www.relaxng.org/">RELAX NG</link> Compact format and later converted into
an XSD schema. If you are familiar with this format, you may wish to examine the <link
xlink:href="http://git.springsource.org/spring-security/spring-security/blobs/3.0.x/config/src/main/resources/org/springframework/security/config/spring-security-3.0.4.rnc"
>schema file</link> directly.</para>
<section xml:id="nsa-http">
<title>Web Application Security - the <literal>&lt;http&gt;</literal> Element</title>
<para> The <literal>&lt;http&gt;</literal> element encapsulates the security configuration
for the web layer of your application. It creates a
<classname>FilterChainProxy</classname> bean named "springSecurityFilterChain" which
maintains the stack of security filters which make up the web security configuration <footnote>
<para>See the <link xlink:href="#ns-web-xml"> introductory chapter</link> for how to set
up the mapping from your <literal>web.xml</literal></para>
</footnote>. Some core filters are always created and others will be added to the stack
depending on the attributes child elements which are present. The positions of the
standard filters are fixed (see <link xlink:href="#filter-stack">the filter order
table</link> in the namespace introduction), removing a common source of errors with
previous versions of the framework when users had to configure the filter chain
explicitly in the<classname>FilterChainProxy</classname> bean. You can, of course, still
do this if you need full control of the configuration. </para>
<para> All filters which require a reference to the
<interfacename>AuthenticationManager</interfacename> will be automatically injected with
the internal instance created by the namespace configuration (see the <link
xlink:href="#ns-auth-manager"> introductory chapter</link> for more on the
<interfacename>AuthenticationManager</interfacename>). </para>
<para> The <literal>&lt;http&gt;</literal> namespace block always creates an
<classname>SecurityContextPersistenceFilter</classname>, an
<classname>ExceptionTranslationFilter</classname> and a
<classname>FilterSecurityInterceptor</classname>. These are fixed and cannot be replaced
with alternatives. </para>
<section xml:id="nsa-http-attributes">
<title><literal>&lt;http&gt;</literal> Attributes</title>
<para> The attributes on the <literal>&lt;http&gt;</literal> element control some of the
properties on the core filters. </para>
<section xml:id="nsa-servlet-api-provision">
<title><literal>servlet-api-provision</literal></title>
<para> Provides versions of <literal>HttpServletRequest</literal> security methods
such as <literal>isUserInRole()</literal> and <literal>getPrincipal()</literal>
which are implemented by adding a
<classname>SecurityContextHolderAwareRequestFilter</classname> bean to the
stack. Defaults to "true". </para>
</section>
<section xml:id="nsa-path-type">
<title><literal>path-type</literal></title>
<para> Controls whether URL patterns are interpreted as ant paths (the default) or
regular expressions. In practice this sets a particular
<interfacename>UrlMatcher</interfacename> instance on the
<classname>FilterChainProxy</classname>. </para>
</section>
<section xml:id="nsa-lowercase-comparisons">
<title><literal>lowercase-comparisons</literal></title>
<para> Whether test URLs should be converted to lower case prior to comparing with
defined path patterns. If unspecified, defaults to "true" </para>
</section>
<section xml:id="nsa-realm">
<title><literal>realm</literal></title>
<para> Sets the realm name used for basic authentication (if enabled). Corresponds
to the <literal>realmName</literal> property on
<classname>BasicAuthenticationEntryPoint</classname>. </para>
</section>
<section xml:id="nsa-entry-point-ref">
<title><literal>entry-point-ref</literal></title>
<para> Normally the <interfacename>AuthenticationEntryPoint</interfacename> used
will be set depending on which authentication mechanisms have been configured.
This attribute allows this behaviour to be overridden by defining a customized
<interfacename>AuthenticationEntryPoint</interfacename> bean which will start
the authentication process. </para>
</section>
<section xml:id="nsa-access-decision-manager-ref">
<title><literal>access-decision-manager-ref</literal></title>
<para> Optional attribute specifying the ID of the
<interfacename>AccessDecisionManager</interfacename> implementation which should
be used for authorizing HTTP requests. By default an
<classname>AffirmativeBased</classname> implementation is used for with a
<classname>RoleVoter</classname> and an
<classname>AuthenticatedVoter</classname>. </para>
</section>
<section xml:id="nsa-access-denied-page">
<title><literal>access-denied-page</literal></title>
<para> Deprecated in favour of the <literal>access-denied-handler</literal> child
element. </para>
</section>
<section xml:id="nsa-once-per-request">
<title><literal>once-per-request</literal></title>
<para> Corresponds to the <literal>observeOncePerRequest</literal> property of
<classname>FilterSecurityInterceptor</classname>. Defaults to "true". </para>
</section>
<section xml:id="create-session">
<title><literal>create-session</literal></title>
<para> Controls the eagerness with which an HTTP session is created. If not set,
defaults to "ifRequired". Other options are "always" and "never". The setting of
this attribute affect the <literal>allowSessionCreation</literal> and
<literal>forceEagerSessionCreation</literal> properties of
<classname>SecurityContextPersistenceFilter</classname>.
<literal>allowSessionCreation</literal> will always be true unless this
attribute is set to "never". <literal>forceEagerSessionCreation</literal> is
"false" unless it is set to "always". So the default configuration allows
session creation but does not force it. The exception is if concurrent session
control is enabled, when <literal>forceEagerSessionCreation</literal> will be
set to true, regardless of what the setting is here. Using "never" would then
cause an exception during the initialization of
<classname>SecurityContextPersistenceFilter</classname>. </para>
</section>
<section xml:id="nsa-use-expressions">
<title><literal>use-expressions</literal></title>
<para>Enables EL-expressions in the <literal>access</literal> attribute, as
described in the chapter on <link xlink:href="#el-access-web">expression-based
access-control</link>. </para>
</section>
<section xml:id="nsa-disable-url-rewriting">
<title><literal>disable-url-rewriting</literal></title>
<para>Prevents session IDs from being appended to URLs in the application. Clients
must use cookies if this attribute is set to <literal>true</literal>. </para>
</section>
</section>
<section xml:id="nsa-access-denied-handler">
<title><literal>&lt;access-denied-handler></literal></title>
<para> This element allows you to set the <literal>errorPage</literal> property for the
default <interfacename>AccessDeniedHandler</interfacename> used by the
<classname>ExceptionTranslationFilter</classname>, (using the
<literal>error-page</literal> attribute, or to supply your own implementation using
the <literal>ref</literal> attribute. This is discussed in more detail in the
section on <link xlink:href="#access-denied-handler">the
<classname>ExceptionTranslationFilter</classname></link>.</para>
</section>
<section>
<title>The <literal>&lt;intercept-url&gt;</literal> Element</title>
<para> This element is used to define the set of URL patterns that the application is
interested in and to configure how they should be handled. It is used to construct
the <interfacename>FilterInvocationSecurityMetadataSource</interfacename> used by
the <classname>FilterSecurityInterceptor</classname> and to exclude particular
patterns from the filter chain entirely (by setting the attribute
<literal>filters="none"</literal>). It is also responsible for configuring a
<classname>ChannelAuthenticationFilter</classname> if particular URLs need to be
accessed by HTTPS, for example. When matching the specified patterns against an
incoming request, the matching is done in the order in which the elements are
declared. So the most specific matches patterns should come first and the most
general should come last.</para>
<section xml:id="nsa-pattern">
<title><literal>pattern</literal></title>
<para> The pattern which defines the URL path. The content will depend on the
<literal>path-type</literal> attribute from the containing http element, so will
default to ant path syntax. </para>
</section>
<section xml:id="nsa-method">
<title><literal>method</literal></title>
<para> The HTTP Method which will be used in combination with the pattern to match
an incoming request. If omitted, any method will match. If an identical pattern
is specified with and without a method, the method-specific match will take
precedence.</para>
</section>
<section xml:id="nsa-access">
<title><literal>access</literal></title>
<para> Lists the access attributes which will be stored in the
<interfacename>FilterInvocationSecurityMetadataSource</interfacename> for the
defined URL pattern/method combination. This should be a comma-separated list of
the security configuration attributes (such as role names). </para>
</section>
<section xml:id="nsa-requires-channel">
<title><literal>requires-channel</literal></title>
<para> Can be <quote>http</quote> or <quote>https</quote> depending on whether a
particular URL pattern should be accessed over HTTP or HTTPS respectively.
Alternatively the value <quote>any</quote> can be used when there is no
preference. If this attribute is present on any
<literal>&lt;intercept-url&gt;</literal> element, then a
<classname>ChannelAuthenticationFilter</classname> will be added to the filter
stack and its additional dependencies added to the application
context.<!--See the chapter on <link
xlink:href="#channel-security-config">channel security</link> for an example
configuration using traditional beans. --></para>
<para> If a <literal>&lt;port-mappings&gt;</literal> configuration is added, this
will be used to by the <classname>SecureChannelProcessor</classname> and
<classname>InsecureChannelProcessor</classname> beans to determine the ports
used for redirecting to HTTP/HTTPS. </para>
</section>
<section>
<title><literal>filters</literal></title>
<para>Can only take the value <quote>none</quote>. This will cause any matching
request to bypass the Spring Security filter chain entirely. None of the rest of
the <literal>&lt;http></literal> configuration will have any effect on the
request and there will be no security context available for its duration. Access
to secured methods during the request will fail.</para>
</section>
</section>
<section>
<title>The <literal>&lt;port-mappings&gt;</literal> Element</title>
<para> By default, an instance of <classname>PortMapperImpl</classname> will be added to
the configuration for use in redirecting to secure and insecure URLs. This element
can optionally be used to override the default mappings which that class defines.
Each child <literal>&lt;port-mapping&gt;</literal> element defines a pair of
HTTP:HTTPS ports. The default mappings are 80:443 and 8080:8443. An example of
overriding these can be found in the <link xlink:href="#ns-requires-channel"
>namespace introduction</link>. </para>
</section>
<section xml:id="nsa-form-login">
<title>The <literal>&lt;form-login&gt;</literal> Element</title>
<para> Used to add an <classname>UsernamePasswordAuthenticationFilter</classname> to the
filter stack and an <classname>LoginUrlAuthenticationEntryPoint</classname> to the
application context to provide authentication on demand. This will always take
precedence over other namespace-created entry points. If no attributes are supplied,
a login page will be generated automatically at the URL "/spring-security-login" <footnote>
<para>This feature is really just provided for convenience and is not intended for
production (where a view technology will have been chosen and can be used to
render a customized login page). The class
<classname>DefaultLoginPageGeneratingFilter</classname> is responsible for
rendering the login page and will provide login forms for both normal form login
and/or OpenID if required.</para>
</footnote> The behaviour can be customized using the following attributes. </para>
<section>
<title><literal>login-page</literal></title>
<para> The URL that should be used to render the login page. Maps to the
<literal>loginFormUrl</literal> property of the
<classname>LoginUrlAuthenticationEntryPoint</classname>. Defaults to
"/spring-security-login". </para>
</section>
<section>
<title><literal>login-processing-url</literal></title>
<para> Maps to the <literal>filterProcessesUrl</literal> property of
<classname>UsernamePasswordAuthenticationFilter</classname>. The default value
is "/j_spring_security_check". </para>
</section>
<section>
<title><literal>default-target-url</literal></title>
<para>Maps to the <literal>defaultTargetUrl</literal> property of
<classname>UsernamePasswordAuthenticationFilter</classname>. If not set, the
default value is "/" (the application root). A user will be taken to this URL
after logging in, provided they were not asked to login while attempting to
access a secured resource, when they will be taken to the originally requested
URL. </para>
</section>
<section>
<title><literal>always-use-default-target</literal></title>
<para> If set to "true", the user will always start at the value given by
<literal>default-target-url</literal>, regardless of how they arrived at the
login page. Maps to the <literal>alwaysUseDefaultTargetUrl</literal> property of
<classname>UsernamePasswordAuthenticationFilter</classname>. Default value is
"false". </para>
</section>
<section>
<title><literal>authentication-failure-url</literal></title>
<para> Maps to the <literal>authenticationFailureUrl</literal> property of
<classname>UsernamePasswordAuthenticationFilter</classname>. Defines the URL the
browser will be redirected to on login failure. Defaults to
"/spring_security_login?login_error", which will be automatically handled by the
automatic login page generator, re-rendering the login page with an error
message. </para>
</section>
<section>
<title><literal>authentication-success-handler-ref</literal></title>
<para>This can be used as an alternative to <literal>default-target-url</literal>
and <literal>always-use-default-target</literal>, giving you full control over
the navigation flow after a successful authentication. The value should be he
name of an <interfacename>AuthenticationSuccessHandler</interfacename> bean in
the application context. </para>
</section>
<section>
<title><literal>authentication-failure-handler-ref</literal></title>
<para>Can be used as an alternative to
<literal>authentication-failure-url</literal>, giving you full control over the
navigation flow after an authentication failure. The value should be he name of
an <interfacename>AuthenticationFailureHandler</interfacename> bean in the
application context. </para>
</section>
</section>
<section xml:id="nsa-http-basic">
<title>The <literal>&lt;http-basic&gt;</literal> Element</title>
<para> Adds a <classname>BasicAuthenticationFilter</classname> and
<classname>BasicAuthenticationEntryPoint</classname> to the configuration. The
latter will only be used as the configuration entry point if form-based login is not
enabled. </para>
</section>
<section xml:id="nsa-remember-me">
<title>The <literal>&lt;remember-me&gt;</literal> Element</title>
<para> Adds the <classname>RememberMeAuthenticationFilter</classname> to the stack. This
in turn will be configured with either a
<classname>TokenBasedRememberMeServices</classname>, a
<classname>PersistentTokenBasedRememberMeServices</classname> or a user-specified
bean implementing <interfacename>RememberMeServices</interfacename> depending on the
attribute settings. </para>
<section>
<title><literal>data-source-ref</literal></title>
<para> If this is set, <classname>PersistentTokenBasedRememberMeServices</classname>
will be used and configured with a
<classname>JdbcTokenRepositoryImpl</classname> instance. </para>
</section>
<section>
<title><literal>token-repository-ref</literal></title>
<para> Configures a <classname>PersistentTokenBasedRememberMeServices</classname>
but allows the use of a custom
<interfacename>PersistentTokenRepository</interfacename> bean. </para>
</section>
<section>
<title><literal>services-ref</literal></title>
<para> Allows complete control of the
<interfacename>RememberMeServices</interfacename> implementation that will be
used by the filter. The value should be the Id of a bean in the application
context which implements this interface. </para>
</section>
<section>
<title><literal>token-repository-ref</literal></title>
<para> Configures a <classname>PersistentTokenBasedRememberMeServices</classname>
but allows the use of a custom
<interfacename>PersistentTokenRepository</interfacename> bean. </para>
</section>
<section>
<title>The <literal>key</literal> Attribute</title>
<para>Maps to the "key" property of
<classname>AbstractRememberMeServices</classname>. Should be set to a unique
value to ensure that remember-me cookies are only valid within the one
application <footnote>
<para>This doesn't affect the use of
<classname>PersistentTokenBasedRememberMeServices</classname>, where the
tokens are stored on the server side.</para>
</footnote>. </para>
</section>
<section>
<title><literal>token-validity-seconds</literal></title>
<para> Maps to the <literal>tokenValiditySeconds</literal> property of
<classname>AbstractRememberMeServices</classname>. Specifies the period in
seconds for which the remember-me cookie should be valid. By default it will be
valid for 14 days. </para>
</section>
<section>
<title><literal>user-service-ref</literal></title>
<para> The remember-me services implementations require access to a
<interfacename>UserDetailsService</interfacename>, so there has to be one
defined in the application context. If there is only one, it will be selected
and used automatically by the namespace configuration. If there are multiple
instances, you can specify a bean Id explicitly using this attribute. </para>
</section>
</section>
<section xml:id="nsa-session-mgmt">
<title>The <literal>&lt;session-management&gt;</literal> Element</title>
<para>Session-management related functionality is implemented by the addition of a
<classname>SessionManagementFilter</classname> to the filter stack.</para>
<section xml:id="session-fixation-protection">
<title><literal>session-fixation-protection</literal></title>
<para> Indicates whether an existing session should be invalidated when a user
authenticates and a new session started. If set to "none" no change will be
made. "newSession" will create a new empty session. "migrateSession" will create
a new session and copy the session attributes to the new session. Defaults to
"migrateSession".</para>
<para> If session fixation protection is enabled, the
<classname>SessionManagementFilter</classname> is inected with a appropriately
configured <classname>DefaultSessionAuthenticationStrategy</classname>. See the
Javadoc for this class for more details. </para>
</section>
</section>
<section xml:id="nsa-concurrent-session-control">
<title>The <literal>&lt;concurrency-control&gt;</literal> Element</title>
<para> Adds support for concurrent session control, allowing limits to be placed on the
number of active sessions a user can have. A
<classname>ConcurrentSessionFilter</classname> will be created, and a
<classname>ConcurrentSessionControlStrategy</classname> will be used with the
<classname>SessionManagementFilter</classname>. If a <literal>form-login</literal>
element has been declared, the strategy object will also be injected into the
created authentication filter. An instance of
<interfacename>SessionRegistry</interfacename> (a
<classname>SessionRegistryImpl</classname> instance unless the user wishes to use a
custom bean) will be created for use by the strategy.</para>
<section>
<title>The <literal>max-sessions</literal> attribute</title>
<para>Maps to the <literal>maximumSessions</literal> property of
<classname>ConcurrentSessionControlStrategy</classname>.</para>
</section>
<section>
<title>The <literal>expired-url</literal> attribute</title>
<para> The URL a user will be redirected to if they attempt to use a session which
has been "expired" by the concurrent session controller because the user has
exceeded the number of allowed sessions and has logged in again elsewhere.
Should be set unless <literal>exception-if-maximum-exceeded</literal> is set. If
no value is supplied, an expiry message will just be written directly back to
the response. </para>
</section>
<section>
<title>The <literal>error-if-maximum-exceeded</literal> attribute</title>
<para>If set to "true" a
<exceptionname>SessionAuthenticationException</exceptionname> will be raised
when a user attempts to exceed the maximum allowed number of sessions. The
default behaviour is to expire the original session. </para>
</section>
<section>
<title>The <literal>session-registry-alias</literal> and
<literal>session-registry-ref</literal> attributes</title>
<para> The user can supply their own <interfacename>SessionRegistry</interfacename>
implementation using the <literal>session-registry-ref</literal> attribute. The
other concurrent session control beans will be wired up to use it. </para>
<para> It can also be useful to have a reference to the internal session registry
for use in your own beans or an admin interface. You can expose the interal bean
using the <literal>session-registry-alias</literal> attribute, giving it a name
that you can use elsewhere in your configuration. </para>
</section>
</section>
<section xml:id="nsa-anonymous">
<title>The <literal>&lt;anonymous&gt;</literal> Element</title>
<para> Adds an <classname>AnonymousAuthenticationFilter</classname> to the stack and an
<classname>AnonymousAuthenticationProvider</classname>. Required if you are using
the <literal>IS_AUTHENTICATED_ANONYMOUSLY</literal> attribute. </para>
</section>
<section xml:id="nsa-x509">
<title>The <literal>&lt;x509&gt;</literal> Element</title>
<para> Adds support for X.509 authentication. An
<classname>X509AuthenticationFilter</classname> will be added to the stack and an
<classname>Http403ForbiddenEntryPoint</classname> bean will be created. The latter
will only be used if no other authentication mechanisms are in use (it's only
functionality is to return an HTTP 403 error code). A
<classname>PreAuthenticatedAuthenticationProvider</classname> will also be created
which delegates the loading of user authorities to a
<interfacename>UserDetailsService</interfacename>. </para>
<section>
<title>The <literal>subject-principal-regex</literal> attribute</title>
<para> Defines a regular expression which will be used to extract the username from
the certificate (for use with the
<interfacename>UserDetailsService</interfacename>). </para>
</section>
<section>
<title>The <literal>user-service-ref</literal> attribute</title>
<para> Allows a specific <interfacename>UserDetailsService</interfacename> to be
used with X.509 in the case where multiple instances are configured. If not set,
an attempt will be made to locate a suitable instance automatically and use
that. </para>
</section>
</section>
<section xml:id="nsa-openid-login">
<title>The <literal>&lt;openid-login&gt;</literal> Element</title>
<para> Similar to <literal>&lt;form-login&gt;</literal> and has the same attributes. The
default value for <literal>login-processing-url</literal> is
"/j_spring_openid_security_check". An
<classname>OpenIDAuthenticationFilter</classname> and
<classname>OpenIDAuthenticationProvider</classname> will be registered. The latter
requires a reference to a <interfacename>UserDetailsService</interfacename>. Again,
this can be specified by Id, using the <literal>user-service-ref</literal>
attribute, or will be located automatically in the application context. </para>
</section>
<section xml:id="nsa-logout">
<title>The <literal>&lt;logout&gt;</literal> Element</title>
<para> Adds a <classname>LogoutFilter</classname> to the filter stack. This is
configured with a <classname>SecurityContextLogoutHandler</classname>. </para>
<section>
<title>The <literal>logout-url</literal> attribute</title>
<para> The URL which will cause a logout (i.e. which will be processed by the
filter). Defaults to "/j_spring_security_logout". </para>
</section>
<section>
<title>The <literal>logout-success-url</literal> attribute</title>
<para> The destination URL which the user will be taken to after logging out.
Defaults to "/". </para>
</section>
<section>
<title>The <literal>invalidate-session</literal> attribute</title>
<para> Maps to the <literal>invalidateHttpSession</literal> of the
<classname>SecurityContextLogoutHandler</classname>. Defaults to "true", so the
session will be invalidated on logout. </para>
</section>
</section>
<section>
<title>The <literal>&lt;custom-filter></literal> Element</title>
<para>This element is used to add a filter to the filter chain. It doesn't create any
additional beans but is used to select a bean of type
<interfacename>javax.servlet.Filter</interfacename> which is already defined in the
appllication context and add that at a particular position in the filter chain
maintained by Spring Security. Full details can be found in the namespace
chapter.</para>
</section>
<section xml:id="nsa-request-cache">
<title>The <literal>request-cache</literal> Element</title>
<para>Sets the <interfacename>RequestCache</interfacename> instance which will be used
by the <classname>ExceptionTranslationFilter</classname> to store request
information before invoking an
<interfacename>AuthenticationEntryPoint</interfacename>. </para>
</section>
<section>
<title>The <literal>&lt;http-firewall></literal> Element</title>
<para>This is a top-level element which can be used to inject a custom implementation of
<interfacename>HttpFirewall</interfacename> into the
<classname>FilterChainProxy</classname> created by the namespace. The default
implementation should be suitable for most applications.</para>
</section>
</section>
<section xml:id="nsa-authentication">
<title>Authentication Services</title>
<para> Before Spring Security 3.0, an <interfacename>AuthenticationManager</interfacename>
was automatically registered internally. Now you must register one explicitly using the
<literal>&lt;authentication-manager&gt;</literal> element. This creates an instance of
Spring Security's <classname>ProviderManager</classname> class, which needs to be
configured with a list of one or more
<interfacename>AuthenticationProvider</interfacename> instances. These can either be
created using syntax elements provided by the namespace, or they can be standard bean
definitions, marked for addition to the list using the
<literal>authentication-provider</literal> element. </para>
<section>
<title>The <literal>&lt;authentication-manager&gt;</literal> Element</title>
<para> Every Spring Security application which uses the namespace must have include this
element somewhere. It is responsible for registering the
<interfacename>AuthenticationManager</interfacename> which provides authentication
services to the application. It also allows you to define an alias name for the
internal instance for use in your own configuration. Its use is described in the
<link xlink:href="#ns-auth-manager">namespace introduction</link>. All elements
which create <interfacename>AuthenticationProvider</interfacename> instances should
be children of this element.</para>
<para> The element also exposes an <literal>erase-credentials</literal> attribute which
maps to the <literal>eraseCredentialsAfterAuthentication</literal> property of the
<classname>ProviderManager</classname>. This is discussed in the <link
xlink:href="#core-services-erasing-credentials">Core Services</link> chapter.</para>
<section>
<title>The <literal>&lt;authentication-provider&gt;</literal> Element</title>
<para> Unless used with a <literal>ref</literal> attribute, this element is
shorthand for configuring a <link xlink:href="#core-services-dao-provider"
><classname>DaoAuthenticationProvider</classname></link>.
<classname>DaoAuthenticationProvider</classname> loads user information from a
<interfacename>UserDetailsService</interfacename> and compares the
username/password combination with the values supplied at login. The
<interfacename>UserDetailsService</interfacename> instance can be defined either
by using an available namespace element (<literal>jdbc-user-service</literal> or
by using the <literal>user-service-ref</literal> attribute to point to a bean
defined elsewhere in the application context). You can find examples of these
variations in the <link xlink:href="#ns-auth-providers">namespace
introduction</link>. </para>
<section>
<title>The <literal>&lt;password-encoder&gt;</literal> Element</title>
<para>Authentication providers can optionally be configured to use a password
encoder as described in the <link xlink:href="#ns-password-encoder"
>namespace introduction</link>. This will result in the bean being injected
with the appropriate <interfacename>PasswordEncoder</interfacename>
instance, potentially with an accompanying
<interfacename>SaltSource</interfacename> bean to provide salt values for
hashing. </para>
</section>
</section>
<section>
<title>Using <literal>&lt;authentication-provider&gt;</literal> to refer to an
<interfacename>AuthenticationProvider</interfacename> Bean</title>
<para> If you have written your own
<interfacename>AuthenticationProvider</interfacename> implementation (or want to
configure one of Spring Security's own implementations as a traditional bean for
some reason, then you can use the following syntax to add it to the internal
<classname>ProviderManager</classname>'s list: <programlisting><![CDATA[
<security:authentication-manager>
<security:authentication-provider ref="myAuthenticationProvider" />
</security:authentication-manager>
<bean id="myAuthenticationProvider" class="com.something.MyAuthenticationProvider"/>
]]></programlisting></para>
</section>
</section>
</section>
<section xml:id="nsa-method-security">
<title>Method Security</title>
<section xml:id="nsa-gms">
<title>The <literal>&lt;global-method-security&gt;</literal> Element</title>
<para> This element is the primary means of adding support for securing methods on
Spring Security beans. Methods can be secured by the use of annotations (defined at
the interface or class level) or by defining a set of pointcuts as child elements,
using AspectJ syntax. </para>
<para> Method security uses the same
<interfacename>AccessDecisionManager</interfacename> configuration as web security,
but this can be overridden as explained above <xref
xlink:href="#nsa-access-decision-manager-ref"/>, using the same attribute. </para>
<section>
<title>The <literal>secured-annotations</literal> and
<literal>jsr250-annotations</literal> Attributes</title>
<para> Setting these to "true" will enable support for Spring Security's own
<literal>@Secured</literal> annotations and JSR-250 annotations, respectively.
They are both disabled by default. Use of JSR-250 annotations also adds a
<classname>Jsr250Voter</classname> to the
<interfacename>AccessDecisionManager</interfacename>, so you need to make sure
you do this if you are using a custom implementation and want to use these
annotations. </para>
</section>
<section>
<title>Securing Methods using <literal>&lt;protect-pointcut&gt;</literal></title>
<para> Rather than defining security attributes on an individual method or class
basis using the <literal>@Secured</literal> annotation, you can define
cross-cutting security constraints across whole sets of methods and interfaces
in your service layer using the <literal>&lt;protect-pointcut&gt;</literal>
element. This has two attributes: <itemizedlist>
<listitem>
<para><literal>expression</literal> - the pointcut expression</para>
</listitem>
<listitem>
<para><literal>access</literal> - the security attributes which apply</para>
</listitem>
</itemizedlist> You can find an example in the <link
xlink:href="#ns-protect-pointcut">namespace introduction</link>. </para>
</section>
<section xml:id="nsa-custom-after-invocation">
<title>The <literal>&lt;after-invocation-provider&gt;</literal> Element</title>
<para> This element can be used to decorate an
<interfacename>AfterInvocationProvider</interfacename> for use by the security
interceptor maintained by the <literal>&lt;global-method-security&gt;</literal>
namespace. You can define zero or more of these within the
<literal>global-method-security</literal> element, each with a
<literal>ref</literal> attribute pointing to an
<interfacename>AfterInvocationProvider</interfacename> bean instance within your
application context. </para>
</section>
</section>
<section>
<title>LDAP Namespace Options</title>
<para> LDAP is covered in some details in <link xlink:href="#ldap">its own
chapter</link>. We will expand on that here with some explanation of how the
namespace options map to Spring beans. The LDAP implementation uses Spring LDAP
extensively, so some familiarity with that project's API may be useful. </para>
<section>
<title>Defining the LDAP Server using the <literal>&lt;ldap-server&gt;</literal>
Element</title>
<para> This element sets up a Spring LDAP
<interfacename>ContextSource</interfacename> for use by the other LDAP beans,
defining the location of the LDAP server and other information (such as a
username and password, if it doesn't allow anonymous access) for connecting to
it. It can also be used to create an embedded server for testing. Details of the
syntax for both options are covered in the <link xlink:href="#ldap-server">LDAP
chapter</link>. The actual <interfacename>ContextSource</interfacename>
implementation is <classname>DefaultSpringSecurityContextSource</classname>
which extends Spring LDAP's <classname>LdapContextSource</classname> class. The
<literal>manager-dn</literal> and <literal>manager-password</literal> attributes
map to the latter's <literal>userDn</literal> and <literal>password</literal>
properties respectively. </para>
<para> If you only have one server defined in your application context, the other
LDAP namespace-defined beans will use it automatically. Otherwise, you can give
the element an "id" attribute and refer to it from other namespace beans using
the <literal>server-ref</literal> attribute. This is actually the bean <literal>id</literal> of the
<literal>ContextSource</literal> instance, if you want to use it in other
traditional Spring beans. </para>
</section>
<section>
<title>The <literal>&lt;ldap-provider&gt;</literal> Element</title>
<para> This element is shorthand for the creation of an
<classname>LdapAuthenticationProvider</classname> instance. By default this will
be configured with a <classname>BindAuthenticator</classname> instance and a
<classname>DefaultAuthoritiesPopulator</classname>. As with all namespace
authentication providers, it must be included as a child of the
<literal>authentication-provider</literal> element.</para>
<section>
<title>The <literal>user-dn-pattern</literal> Attribute</title>
<para> If your users are at a fixed location in the directory (i.e. you can work
out the DN directly from the username without doing a directory search), you
can use this attribute to map directly to the DN. It maps directly to the
<literal>userDnPatterns</literal> property of
<classname>AbstractLdapAuthenticator</classname>. </para>
</section>
<section>
<title>The <literal>user-search-base</literal> and
<literal>user-search-filter</literal> Attributes</title>
<para> If you need to perform a search to locate the user in the directory, then
you can set these attributes to control the search. The
<classname>BindAuthenticator</classname> will be configured with a
<classname>FilterBasedLdapUserSearch</classname> and the attribute values
map directly to the first two arguments of that bean's constructor. If these
attributes aren't set and no <literal>user-dn-pattern</literal> has been
supplied as an alternative, then the default search values of
<literal>user-search-filter="(uid={0})"</literal> and
<literal>user-search-base=""</literal> will be used. </para>
</section>
<section>
<title><literal>group-search-filter</literal>,
<literal>group-search-base</literal>,
<literal>group-role-attribute</literal> and <literal>role-prefix</literal>
Attributes</title>
<para> The value of <literal>group-search-base</literal> is mapped to the
<literal>groupSearchBase</literal> constructor argument of
<classname>DefaultAuthoritiesPopulator</classname> and defaults to
"ou=groups". The default filter value is "(uniqueMember={0})", which assumes
that the entry is of type "groupOfUniqueNames".
<literal>group-role-attribute</literal> maps to the
<literal>groupRoleAttribute</literal> attribute and defaults to "cn".
Similarly <literal>role-prefix</literal> maps to
<literal>rolePrefix</literal> and defaults to "ROLE_". </para>
</section>
<section>
<title>The <literal>&lt;password-compare&gt;</literal> Element</title>
<para> This is used as child element to <literal>&lt;ldap-provider&gt;</literal>
and switches the authentication strategy from
<classname>BindAuthenticator</classname> to
<classname>PasswordComparisonAuthenticator</classname>. This can optionally
be supplied with a <literal>hash</literal> attribute or with a child
<literal>&lt;password-encoder&gt;</literal> element to hash the password
before submitting it to the directory for comparison. </para>
</section>
</section>
<section>
<title>The <literal>&lt;ldap-user-service&gt;</literal> Element</title>
<para> This element configures an LDAP
<interfacename>UserDetailsService</interfacename>. The class used is
<classname>LdapUserDetailsService</classname> which is a combination of a
<classname>FilterBasedLdapUserSearch</classname> and a
<classname>DefaultAuthoritiesPopulator</classname>. The attributes it supports
have the same usage as in <literal>&lt;ldap-provider&gt;</literal>. </para>
</section>
</section>
</section>
</appendix>