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 introductory chapter 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 RELAX NG Compact format and later converted into an XSD schema. If you are familiar with this format, you may wish to examine the schema file directly.
The <http> element encapsulates the security configuration
for the web layer of your application. It creates a
FilterChainProxy bean named "springSecurityFilterChain" which
maintains the stack of security filters which make up the web security configuration [19]. 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 the filter order
table 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 theFilterChainProxy bean. You can, of course, still
do this if you need full control of the configuration.
All filters which require a reference to the
AuthenticationManager will be automatically injected with
the internal instance created by the namespace configuration (see the introductory chapter for more on the
AuthenticationManager).
The <http> namespace block always creates an
SecurityContextPersistenceFilter, an
ExceptionTranslationFilter and a
FilterSecurityInterceptor. These are fixed and cannot be replaced
with alternatives.
The attributes on the <http> element control some of the
properties on the core filters.
Provides versions of HttpServletRequest security methods
such as isUserInRole() and getPrincipal()
which are implemented by adding a
SecurityContextHolderAwareRequestFilter bean to the
stack. Defaults to "true".
Controls whether URL patterns are interpreted as ant paths (the default) or
regular expressions. In practice this sets a particular
UrlMatcher instance on the
FilterChainProxy.
Whether test URLs should be converted to lower case prior to comparing with defined path patterns. If unspecified, defaults to "true"
Sets the realm name used for basic authentication (if enabled). Corresponds
to the realmName property on
BasicAuthenticationEntryPoint.
Normally the AuthenticationEntryPoint used
will be set depending on which authentication mechanisms have been configured.
This attribute allows this behaviour to be overridden by defining a customized
AuthenticationEntryPoint bean which will start
the authentication process.
Optional attribute specifying the ID of the
AccessDecisionManager implementation which should
be used for authorizing HTTP requests. By default an
AffirmativeBased implementation is used for with a
RoleVoter and an
AuthenticatedVoter.
Corresponds to the observeOncePerRequest property of
FilterSecurityInterceptor. Defaults to "true".
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 allowSessionCreation and
forceEagerSessionCreation properties of
SecurityContextPersistenceFilter.
allowSessionCreation will always be true unless this
attribute is set to "never". forceEagerSessionCreation 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 forceEagerSessionCreation will be
set to true, regardless of what the setting is here. Using "never" would then
cause an exception during the initialization of
SecurityContextPersistenceFilter.
Enables EL-expressions in the access attribute, as
described in the chapter on expression-based
access-control.
This element allows you to set the errorPage property for the
default AccessDeniedHandler used by the
ExceptionTranslationFilter, (using the
error-page attribute, or to supply your own implementation using
the ref attribute. This is discussed in more detail in the
section on the
ExceptionTranslationFilter.
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 FilterInvocationSecurityMetadataSource used by
the FilterSecurityInterceptor and to exclude particular
patterns from the filter chain entirely (by setting the attribute
filters="none"). It is also responsible for configuring a
ChannelAuthenticationFilter 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.
The pattern which defines the URL path. The content will depend on the
path-type attribute from the containing http element, so will
default to ant path syntax.
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.
Lists the access attributes which will be stored in the
FilterInvocationSecurityMetadataSource for the
defined URL pattern/method combination. This should be a comma-separated list of
the security configuration attributes (such as role names).
Can be “http” or “https” depending on whether a
particular URL pattern should be accessed over HTTP or HTTPS respectively.
Alternatively the value “any” can be used when there is no
preference. If this attribute is present on any
<intercept-url> element, then a
ChannelAuthenticationFilter will be added to the filter
stack and its additional dependencies added to the application
context.
If a <port-mappings> configuration is added, this
will be used to by the SecureChannelProcessor and
InsecureChannelProcessor beans to determine the ports
used for redirecting to HTTP/HTTPS.
Can only take the value “none”. This will cause any matching
request to bypass the Spring Security filter chain entirely. None of the rest of
the <http> 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.
By default, an instance of PortMapperImpl 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 <port-mapping> 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 namespace introduction.
Used to add an UsernamePasswordAuthenticationFilter to the
filter stack and an LoginUrlAuthenticationEntryPoint 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" [20] The behaviour can be customized using the following attributes.
The URL that should be used to render the login page. Maps to the
loginFormUrl property of the
LoginUrlAuthenticationEntryPoint. Defaults to
"/spring-security-login".
Maps to the filterProcessesUrl property of
UsernamePasswordAuthenticationFilter. The default value
is "/j_spring_security_check".
Maps to the defaultTargetUrl property of
UsernamePasswordAuthenticationFilter. 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.
If set to "true", the user will always start at the value given by
default-target-url, regardless of how they arrived at the
login page. Maps to the alwaysUseDefaultTargetUrl property of
UsernamePasswordAuthenticationFilter. Default value is
"false".
Maps to the authenticationFailureUrl property of
UsernamePasswordAuthenticationFilter. 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.
This can be used as an alternative to default-target-url
and always-use-default-target, giving you full control over
the navigation flow after a successful authentication. The value should be he
name of an AuthenticationSuccessHandler bean in
the application context.
Adds a BasicAuthenticationFilter and
BasicAuthenticationEntryPoint to the configuration. The
latter will only be used as the configuration entry point if form-based login is not
enabled.
Adds the RememberMeAuthenticationFilter to the stack. This
in turn will be configured with either a
TokenBasedRememberMeServices, a
PersistentTokenBasedRememberMeServices or a user-specified
bean implementing RememberMeServices depending on the
attribute settings.
If this is set, PersistentTokenBasedRememberMeServices
will be used and configured with a
JdbcTokenRepositoryImpl instance.
Configures a PersistentTokenBasedRememberMeServices
but allows the use of a custom
PersistentTokenRepository bean.
Allows complete control of the
RememberMeServices 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.
Configures a PersistentTokenBasedRememberMeServices
but allows the use of a custom
PersistentTokenRepository bean.
Maps to the "key" property of
AbstractRememberMeServices. Should be set to a unique
value to ensure that remember-me cookies are only valid within the one
application [21].
Maps to the tokenValiditySeconds property of
AbstractRememberMeServices. Specifies the period in
seconds for which the remember-me cookie should be valid. By default it will be
valid for 14 days.
The remember-me services implementations require access to a
UserDetailsService, 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.
Session-management related functionality is implemented by the addition of a
SessionManagementFilter to the filter stack.
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".
If session fixation protection is enabled, the
SessionManagementFilter is injected with an appropriately
configured DefaultSessionAuthenticationStrategy. See the
Javadoc for this class for more details.
Adds support for concurrent session control, allowing limits to be placed on the
number of active sessions a user can have. A
ConcurrentSessionFilter will be created, and a
ConcurrentSessionControlStrategy will be used with the
SessionManagementFilter. If a form-login
element has been declared, the strategy object will also be injected into the
created authentication filter. An instance of
SessionRegistry (a
SessionRegistryImpl instance unless the user wishes to use a
custom bean) will be created for use by the strategy.
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 exception-if-maximum-exceeded is set. If
no value is supplied, an expiry message will just be written directly back to
the response.
If set to "true" a
SessionAuthenticationException will be raised
when a user attempts to exceed the maximum allowed number of sessions. The
default behaviour is to expire the original session.
The user can supply their own SessionRegistry
implementation using the session-registry-ref attribute. The
other concurrent session control beans will be wired up to use it.
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 session-registry-alias attribute, giving it a name
that you can use elsewhere in your configuration.
Adds an AnonymousAuthenticationFilter to the stack and an
AnonymousAuthenticationProvider. Required if you are using
the IS_AUTHENTICATED_ANONYMOUSLY attribute.
Adds support for X.509 authentication. An
X509AuthenticationFilter will be added to the stack and an
Http403ForbiddenEntryPoint 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
PreAuthenticatedAuthenticationProvider will also be created
which delegates the loading of user authorities to a
UserDetailsService.
Defines a regular expression which will be used to extract the username from
the certificate (for use with the
UserDetailsService).
Similar to <form-login> and has the same attributes. The
default value for login-processing-url is
"/j_spring_openid_security_check". An
OpenIDAuthenticationFilter and
OpenIDAuthenticationProvider will be registered. The latter
requires a reference to a UserDetailsService. Again,
this can be specified by Id, using the user-service-ref
attribute, or will be located automatically in the application context.
Adds a LogoutFilter to the filter stack. This is
configured with a SecurityContextLogoutHandler.
The URL which will cause a logout (i.e. which will be processed by the filter). Defaults to "/j_spring_security_logout".
The destination URL which the user will be taken to after logging out. Defaults to "/".
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
javax.servlet.Filter 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.
Sets the RequestCache instance which will be used
by the ExceptionTranslationFilter to store request
information before invoking an
AuthenticationEntryPoint.
Before Spring Security 3.0, an AuthenticationManager
was automatically registered internally. Now you must register one explicitly using the
<authentication-manager> element. This creates an instance of
Spring Security's ProviderManager class, which needs to be
configured with a list of one or more
AuthenticationProvider 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
authentication-provider element.
Every Spring Security application which uses the namespace must have include this
element somewhere. It is responsible for registering the
AuthenticationManager 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
namespace introduction. All elements
which create AuthenticationProvider instances should
be children of this element.
The element also exposes an erase-credentials attribute which
maps to the eraseCredentialsAfterAuthentication property of the
ProviderManager. This is discussed in the Core Services chapter.
Unless used with a ref attribute, this element is
shorthand for configuring a DaoAuthenticationProvider.
DaoAuthenticationProvider loads user information from a
UserDetailsService and compares the
username/password combination with the values supplied at login. The
UserDetailsService instance can be defined either
by using an available namespace element (jdbc-user-service or
by using the user-service-ref attribute to point to a bean
defined elsewhere in the application context). You can find examples of these
variations in the namespace
introduction.
Authentication providers can optionally be configured to use a password
encoder as described in the namespace introduction. This will result in the bean being injected
with the appropriate PasswordEncoder
instance, potentially with an accompanying
SaltSource bean to provide salt values for
hashing.
If you have written your own
AuthenticationProvider 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
ProviderManager's list:
<security:authentication-manager>
<security:authentication-provider ref="myAuthenticationProvider" />
</security:authentication-manager>
<bean id="myAuthenticationProvider" class="com.something.MyAuthenticationProvider"/>
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.
Method security uses the same
AccessDecisionManager configuration as web security,
but this can be overridden as explained above the section called “access-decision-manager-ref”, using the same attribute.
Setting these to "true" will enable support for Spring Security's own
@Secured annotations and JSR-250 annotations, respectively.
They are both disabled by default. Use of JSR-250 annotations also adds a
Jsr250Voter to the
AccessDecisionManager, so you need to make sure
you do this if you are using a custom implementation and want to use these
annotations.
Rather than defining security attributes on an individual method or class
basis using the @Secured annotation, you can define
cross-cutting security constraints across whole sets of methods and interfaces
in your service layer using the <protect-pointcut>
element. This has two attributes:
expression - the pointcut expression
access - the security attributes which apply
You can find an example in the namespace introduction.
This element can be used to decorate an
AfterInvocationProvider for use by the security
interceptor maintained by the <global-method-security>
namespace. You can define zero or more of these within the
global-method-security element, each with a
ref attribute pointing to an
AfterInvocationProvider bean instance within your
application context.
LDAP is covered in some details in its own chapter. 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.
This element sets up a Spring LDAP
ContextSource 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 LDAP
chapter. The actual ContextSource
implementation is DefaultSpringSecurityContextSource
which extends Spring LDAP's LdapContextSource class. The
manager-dn and manager-password attributes
map to the latter's userDn and password
properties respectively.
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 server-ref attribute. This is actually the bean id of the
ContextSource instance, if you want to use it in other
traditional Spring beans.
This element is shorthand for the creation of an
LdapAuthenticationProvider instance. By default this will
be configured with a BindAuthenticator instance and a
DefaultAuthoritiesPopulator. As with all namespace
authentication providers, it must be included as a child of the
authentication-provider element.
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
userDnPatterns property of
AbstractLdapAuthenticator.
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
BindAuthenticator will be configured with a
FilterBasedLdapUserSearch and the attribute values
map directly to the first two arguments of that bean's constructor. If these
attributes aren't set and no user-dn-pattern has been
supplied as an alternative, then the default search values of
user-search-filter="(uid={0})" and
user-search-base="" will be used.
The value of group-search-base is mapped to the
groupSearchBase constructor argument of
DefaultAuthoritiesPopulator and defaults to
"ou=groups". The default filter value is "(uniqueMember={0})", which assumes
that the entry is of type "groupOfUniqueNames".
group-role-attribute maps to the
groupRoleAttribute attribute and defaults to "cn".
Similarly role-prefix maps to
rolePrefix and defaults to "ROLE_".
This is used as child element to <ldap-provider>
and switches the authentication strategy from
BindAuthenticator to
PasswordComparisonAuthenticator. This can optionally
be supplied with a hash attribute or with a child
<password-encoder> element to hash the password
before submitting it to the directory for comparison.
[19] See the introductory chapter for how to set
up the mapping from your web.xml
[20] 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
DefaultLoginPageGeneratingFilter is responsible for
rendering the login page and will provide login forms for both normal form login
and/or OpenID if required.
[21] This doesn't affect the use of
PersistentTokenBasedRememberMeServices, where the
tokens are stored on the server side.