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How exactly works this Spring Security example?

I am pretty new in Spring Security and I have some doubt related the configuration found into a tutorial.
This is the spring-security.xml file used to the Spring Security configuration into the project:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:security="http://www.springframework.org/schema/security"
xsi:schemaLocation="http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-4.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<security:http>
<security:intercept-url pattern="/springLogin" access="permitAll"/>
<security:intercept-url pattern="/doSpringLogin" access="permitAll"/>
<security:intercept-url pattern="/myprofile" access="hasRole('ROLE_USER')"/>
<security:intercept-url pattern="/springHome" access="hasRole('ROLE_USER')"/>
<security:intercept-url pattern="/products" access="hasRole('ROLE_USER')"/>
<security:intercept-url pattern="/springLogout" access="permitAll"/>
<security:intercept-url pattern="/springLogin?error=true" access="permitAll"/>
<security:form-login login-page="/springLogin" login-processing-url="/doSpringLogin"
default-target-url="/springHome" authentication-failure-url="/springLogin?error=true"
username-parameter="username" password-parameter="password"
/>
<security:csrf disabled="true"/>
<security:logout logout-url="/springLogout" logout-success-url="/springLogin"/>
</security:http>
<bean id="userDetailsServiceImpl" class="com.demo.security.UserDetailsServiceImpl"></bean>
<bean id="authenticationProvider" class="org.springframework.security.authentication.dao.DaoAuthenticationProvider">
<property name="userDetailsService" ref="userDetailsServiceImpl"></property>
</bean>
<bean id="authenticationManager" class="org.springframework.security.authentication.ProviderManager">
<constructor-arg name="providers">
<list>
<ref bean="authenticationProvider"/>
</list>
</constructor-arg>
</bean>
<security:authentication-manager>
<security:authentication-provider user-service-ref="userDetailsServiceImpl">
<security:password-encoder hash="plaintext"></security:password-encoder>
</security:authentication-provider>
</security:authentication-manager>
</beans>
I it divided into some section. The first one is the tag content.
It contains something as:
<security:intercept-url pattern="/springLogin" access="permitAll"/>
that I think means that the page related to the /springLogin resource is accessible to everyone while
<security:intercept-url pattern="/myprofile" access="hasRole('ROLE_USER')"/>
means that the resource related to the /myprofile resource is accessible only to the logged user (the principal) having a ROLE_USER role setted.
Is it this reasoning correct?
Then in the previous configuration file there is:
1) The declaration of the authenticationManager bean:
<bean id="authenticationManager" class="org.springframework.security.authentication.ProviderManager">
<constructor-arg name="providers">
<list>
<ref bean="authenticationProvider"/>
</list>
</constructor-arg>
</bean>
that I think it is used by Spring to populate the SecurityContext with the Principal objects (for example all the user of a web application) and with the Authorities (what a specific Principal can do).
Is this reasoning correct?
This object take as constructor arg a list of autentication provider bean that have to provide the Principal informations (so for example the role associated to a specific Principal)
In this case is provided an implementation of the DaoAuthenticationProvider class that take a bean having name="userDetailsService" as property, this one:
<bean id="userDetailsServiceImpl" class="com.demo.security.UserDetailsServiceImpl"></bean>
that is an instance of the UserDetailsServiceImpl class, this one:
public class UserDetailsServiceImpl implements UserDetailsService {
#Override
public UserDetails loadUserByUsername(String username)
throws UsernameNotFoundException {
System.out.println(username);
User user = RegisteryDAO.getUserDAO().getUserByUsername(username);
if(user == null){
return null;
}
List<GrantedAuthority> authorities = new ArrayList<GrantedAuthority>();
authorities.add(new SimpleGrantedAuthority(user.getRole()));
UserDetails userDetails = new org.springframework.security.core.userdetails.
User(user.getUsername(), user.getPassword(), true, true, true, true, authorities);
return userDetails;
}
}
So what exactly happen?
Using the debugger it seems to me that when te user try to access to a specific page this loadUserByUsername() return the UserDetails object related to the logged user that contain the List representing the roles associated to the specific logged user (for example the previous ROLE_USER)
Then I think that Spring automatically use the
<security:intercept-url pattern="/myprofile" access="hasRole('ROLE_USER')"/>
to check if the user have setted the propper role into the previous List list.
If it have so forward the request to the controller method that handle this Http Request otherwise avoid that this HttpRequest come to this controller method and show a page that say that the user can't access to this resource.

Here is an explanation of some of the concepts and questions you are asking about.
AuthenticationManager
AuthenticationManager is the component responsible for processing the Authentication request. The Authentication request might be instance of UsernamePasswordAuthenticationToken for username/password logins.
For other implementations look at Authentication JavaDoc.
AuthenticationManager also has collection of AuthenticationProvider implementations. These components are capable of processing specific Authentication types and AuthenticationManager iterates through them attempting to find one capable of handling the Authentication passed to it. If it finds one, it calls it with Authentication object presented and returns fully populated Authentication object if successful (otherwise AuthenticationException is thrown).
AuthenticationProvider
As mentioned above, AuthenticationProvider processes certain type of Authentication request. For instance the DaoAuthenticationProvider will perform following steps when called by AuthenticationManager:
Take the UsernamePasswordAuthenticationToken passed to it
Use the UserDetailsService service implementation provided to it (in your case it is UserDetailServiceImpl) to look up user by username
Check the password provided in the authentication token against the user using PasswordEncoder and SaltSource, if specified.
If the authentication succeeds, returns the populated Authentication object (UsernamePasswordAuthenticationToken in this case), which contains principal, credentials and is marked as authenticated
In case the authentication fails, AuthenticationException will be thrown
DaoAuthenticationProvider which you are using which is capable of processing UsernamePasswordAuthenticationToken requests. So typically form logins, and so on. You can see which types of authentications provider support by looking at its supports() method implementation, which in case of DaoAuthenticationProvider looks like this:
public boolean supports(Class<?> authentication) {
return (UsernamePasswordAuthenticationToken.class.isAssignableFrom(authentication));
}
Spring Security Filter Chain
Now let's look at the Security filter chain, as defined by Spring Security documentation:
The order that filters are defined in the chain is very important.
Irrespective of which filters you are actually using, the order should
be as follows:
ChannelProcessingFilter, because it might need to redirect to a different protocol
SecurityContextPersistenceFilter, so a SecurityContext can be set up in the SecurityContextHolder at the beginning of a web request, and
any changes to the SecurityContext can be copied to the HttpSession
when the web request ends (ready for use with the next web request)
ConcurrentSessionFilter, because it uses the SecurityContextHolder functionality but needs to update the SessionRegistry to reflect
ongoing requests from the principal
Authentication processing mechanisms - UsernamePasswordAuthenticationFilter, CasAuthenticationFilter,
BasicAuthenticationFilter etc - so that the SecurityContextHolder can
be modified to contain a valid Authentication request token
The SecurityContextHolderAwareRequestFilter, if you are using it to install a Spring Security aware HttpServletRequestWrapper into your
servlet container
RememberMeAuthenticationFilter, so that if no earlier authentication processing mechanism updated the SecurityContextHolder,
and the request presents a cookie that enables remember-me services to
take place, a suitable remembered Authentication object will be put
there
AnonymousAuthenticationFilter, so that if no earlier authentication processing mechanism updated the SecurityContextHolder,
an anonymous Authentication object will be put there
ExceptionTranslationFilter, to catch any Spring Security exceptions so that either an HTTP error response can be returned or an
appropriate AuthenticationEntryPoint can be launched
FilterSecurityInterceptor, to protect web URIs and raise exceptions when access is denied
When the user submits login form, AuthenticationManager is called at step 4 in the filter chain. In the case of form login it would be handled by UsernamePasswordAuthenticationFilter which calls the AuthenticationManager to process the authentication:
public Authentication attemptAuthentication(HttpServletRequest request,
HttpServletResponse response) throws AuthenticationException {
// ...
return this.getAuthenticationManager().authenticate(authRequest);
}
Using the debugger it seems to me that when te user try to access to a specific page this loadUserByUsername() return the UserDetails
Actually the loadUserByUsername() is called when user authenticates, for instance after submitting login form. If the user is already authenticated this is not called.
I think that means that the page related to the /springLogin resource is accessible to everyone:
<security:intercept-url pattern="/springLogin" access="permitAll" />
Then I think that Spring will automatically use following to check if the user has proper role:
<security:intercept-url pattern="/myprofile" access="hasRole('ROLE_USER')" />
Correct. This process is handled by FilterSecurityInterceptor, which extends AbstractSecurityInterceptor - core Spring Security component dealing with authorization. If the user is not authenticated or doesn't have the required role an Exception is thrown and handled by the ExceptionTranslationFilter. This filter handles Security exceptions. For instance in case of authentication failure it will redirect user to authentication entry point, e.g. the login page.
Internal architecture of Spring Security is pretty nicely described in the reference documentation. I recommend to take a look at it.

SwitchUserFilter not working in Spring security when used with Basic Authentication

I am having a problem with SwitchUserFilter in Spring security. I have following configuration:
<bean id="ldapUserSearch" class="org.springframework.security.ldap.search.FilterBasedLdapUserSearch">
<constructor-arg name="searchBase" value=""/>
<constructor-arg name="searchFilter" value="(uid={0})"/>
<constructor-arg name="contextSource" ref="ldapContext"/>
</bean>
<security:ldap-server id="ldapContext" url="ldap://xxxxxxx"/>
<bean id="ldapAuthProvider" class="org.springframework.security.ldap.authentication.LdapAuthenticationProvider">
<constructor-arg name="authenticator">
<bean
class="org.springframework.security.ldap.authentication.BindAuthenticator">
<constructor-arg ref="ldapContext" />
<property name="userSearch" ref="ldapUserSearch" />
</bean>
</constructor-arg>
<constructor-arg name="authoritiesPopulator" ref="dbLDAPAuthPopulator" />
</bean>
<security:authentication-manager>
<security:authentication-provider ref="ldapAuthProvider"/>
</security:authentication-manager>
And the corresponding SwitchUserFilter bean is created as:
SwitchUserFilter switchUserFilter = new SwitchUserFilter();
switchUserFilter.setUserDetailsService(ldapUserDetailsService);
switchUserFilter.setTargetUrl("/");
switchUserFilter.setSwitchUserUrl("/impersonate");
switchUserFilter.setUsernameParameter("username");
switchUserFilter.setExitUserUrl("/unimpersonate");
When I go to the url "/impersonate" the user gets impersonated properly. However when the redirect is send to the target url i.e. "/" the user is again authenticated using basic auth.
I had a look at the code of both the SwitchUserFilter and BasicAuthenticationFilter and seems that SU will not work with basic auth.
This is what happens:
When the /impersonate?username=xyz url is called it goes to SwitchUserFilter which gets the details of xyz user from the ldap and it then sets the securitycontext in the session. Code snippet is as follows:
if (requiresSwitchUser(request)) {
// if set, attempt switch and store original
try {
Authentication targetUser = attemptSwitchUser(request);
// update the current context to the new target user
SecurityContextHolder.getContext().setAuthentication(targetUser);
// redirect to target url
successHandler.onAuthenticationSuccess(request, response, targetUser);
} catch (AuthenticationException e) {
logger.debug("Switch User failed", e);
failureHandler.onAuthenticationFailure(request, response, e);
}
return;
So in the SecurityContext you have information about xyz user.
Then when it redirects to target url i.e. "/" basicAuthenticationFilter is called which checks whether the user is authenticated. Code snippet:
Authentication existingAuth = SecurityContextHolder.getContext().getAuthentication();
if(existingAuth == null || !existingAuth.isAuthenticated()) {
return true;
}
// Limit username comparison to providers which use usernames (ie UsernamePasswordAuthenticationToken)
// (see SEC-348)
if (existingAuth instanceof UsernamePasswordAuthenticationToken && !existingAuth.getName().equals(username)) {
return true;
}
// Handle unusual condition where an AnonymousAuthenticationToken is already present
// This shouldn't happen very often, as BasicProcessingFitler is meant to be earlier in the filter
// chain than AnonymousAuthenticationFilter. Nevertheless, presence of both an AnonymousAuthenticationToken
// together with a BASIC authentication request header should indicate reauthentication using the
// BASIC protocol is desirable. This behaviour is also consistent with that provided by form and digest,
// both of which force re-authentication if the respective header is detected (and in doing so replace
// any existing AnonymousAuthenticationToken). See SEC-610.
if (existingAuth instanceof AnonymousAuthenticationToken) {
return true;
}
return false;
As you can see it checks existingAuth.getName().equals(username)) which in this case it is xyz. However logged in user is different so the filter again authenticates the user and all the work done by SwitchUserFilter is overridden.
Is their any way to solve this issue? Can I override the BasicAuthenticationFilter?

This question is quite old, however should anyone come across it the answer is still valid today. You don't show your <http /> stanzas for Spring Security but you need to ensure that the role granted by impersonation is the same role (authority) required to bypass authentication at /*. If it's not then yes, you will be asked to authenticate.
You can specify custom authorities to be granted on impersonation by implementing an extension of SwitchUserAuthorityChanger and passing a reference of it to SwitchUserFilter.

RESTful Authentication via Spring

Problem:
We have a Spring MVC-based RESTful API which contains sensitive information. The API should be secured, however sending the user's credentials (user/pass combo) with each request is not desirable. Per REST guidelines (and internal business requirements), the server must remain stateless. The API will be consumed by another server in a mashup-style approach.
Requirements:
Client makes a request to .../authenticate (unprotected URL) with credentials; server returns a secure token which contains enough information for the server to validate future requests and remain stateless. This would likely consist of the same information as Spring Security's Remember-Me Token.
Client makes subsequent requests to various (protected) URLs, appending the previously obtained token as a query parameter (or, less desirably, an HTTP request header).
Client cannot be expected to store cookies.
Since we use Spring already, the solution should make use of Spring Security.
We've been banging our heads against the wall trying to make this work, so hopefully someone out there has already solved this problem.
Given the above scenario, how might you solve this particular need?

We managed to get this working exactly as described in the OP, and hopefully someone else can make use of the solution. Here's what we did:
Set up the security context like so:
<security:http realm="Protected API" use-expressions="true" auto-config="false" create-session="stateless" entry-point-ref="CustomAuthenticationEntryPoint">
<security:custom-filter ref="authenticationTokenProcessingFilter" position="FORM_LOGIN_FILTER" />
<security:intercept-url pattern="/authenticate" access="permitAll"/>
<security:intercept-url pattern="/**" access="isAuthenticated()" />
</security:http>
<bean id="CustomAuthenticationEntryPoint"
class="com.demo.api.support.spring.CustomAuthenticationEntryPoint" />
<bean id="authenticationTokenProcessingFilter"
class="com.demo.api.support.spring.AuthenticationTokenProcessingFilter" >
<constructor-arg ref="authenticationManager" />
</bean>
As you can see, we've created a custom AuthenticationEntryPoint, which basically just returns a 401 Unauthorized if the request wasn't authenticated in the filter chain by our AuthenticationTokenProcessingFilter.
CustomAuthenticationEntryPoint:
public class CustomAuthenticationEntryPoint implements AuthenticationEntryPoint {
#Override
public void commence(HttpServletRequest request, HttpServletResponse response,
AuthenticationException authException) throws IOException, ServletException {
response.sendError( HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized: Authentication token was either missing or invalid." );
}
}
AuthenticationTokenProcessingFilter:
public class AuthenticationTokenProcessingFilter extends GenericFilterBean {
#Autowired UserService userService;
#Autowired TokenUtils tokenUtils;
AuthenticationManager authManager;
public AuthenticationTokenProcessingFilter(AuthenticationManager authManager) {
this.authManager = authManager;
}
#Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
#SuppressWarnings("unchecked")
Map<String, String[]> parms = request.getParameterMap();
if(parms.containsKey("token")) {
String token = parms.get("token")[0]; // grab the first "token" parameter
// validate the token
if (tokenUtils.validate(token)) {
// determine the user based on the (already validated) token
UserDetails userDetails = tokenUtils.getUserFromToken(token);
// build an Authentication object with the user's info
UsernamePasswordAuthenticationToken authentication =
new UsernamePasswordAuthenticationToken(userDetails.getUsername(), userDetails.getPassword());
authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails((HttpServletRequest) request));
// set the authentication into the SecurityContext
SecurityContextHolder.getContext().setAuthentication(authManager.authenticate(authentication));
}
}
// continue thru the filter chain
chain.doFilter(request, response);
}
}
Obviously, TokenUtils contains some privy (and very case-specific) code and can't be readily shared. Here's its interface:
public interface TokenUtils {
String getToken(UserDetails userDetails);
String getToken(UserDetails userDetails, Long expiration);
boolean validate(String token);
UserDetails getUserFromToken(String token);
}
That ought to get you off to a good start.

You might consider Digest Access Authentication. Essentially the protocol is as follows:
Request is made from client
Server responds with a unique nonce string
Client supplies a username and password (and some other values) md5 hashed with the nonce; this hash is known as HA1
Server is then able to verify client's identity and serve up the requested materials
Communication with the nonce can continue until the server supplies a new nonce (a counter is used to eliminate replay attacks)
All of this communication is made through headers, which, as jmort253 points out, is generally more secure than communicating sensitive material in the url parameters.
Digest Access Authentication is supported by Spring Security. Notice that, although the docs say that you must have access to your client's plain-text password, you can successfully authenticate if you have the HA1 hash for your client.

Regarding tokens carrying information, JSON Web Tokens (http://jwt.io) is a brilliant technology. The main concept is to embed information elements (claims) into the token, and then signing the whole token so that the validating end can verify that the claims are indeed trustworthy.
I use this Java implementation: https://bitbucket.org/b_c/jose4j/wiki/Home
There is also a Spring module (spring-security-jwt), but I haven't looked into what it supports.

Why don't you start using OAuth with JSON WebTokens
http://projects.spring.io/spring-security-oauth/
OAuth2 is an standardized authorization protocol/framework. As per Official OAuth2 Specification:
You can find more info here

#PreAuthorize on spring controller sending redirect if authorization fails

I've got spring security successfully evaluating a #PreAuthorize on my controller. If i use "permitAll" then I can view the page, and if I use "isAuthenticated()" then I get an ugly Access is Denied stack trace. If I put the configuration in an intercept-url within the http node in my security context configuration xml file then I am nicely redirected to the login page instead of getting the nasty stack trace right in my page.
Is there a way for me to get the redirection with the annotation mechanism only?

I got this to work. There were a couple of things I had to deal with.
First, my Spring MVC configuration had a SimpleMappingExceptionResolver with a defaultErrorView configured. That was intercepting the Authentication and Authorization errors before they could get to the access-denied-handler that I had configured in the http element in my security configuration. The final code looks something like this.
securitycontext.xml
<global-method-security pre-post-annotations="enabled"/>
<!-- HTTP security configurations -->
<http auto-config="false" use-expressions="true" entry-point-ref="loginUrlAuthenticationEntryPoint">
<access-denied-handler ref="myAccessDeniedHandler" />
... other configuration here ...
</http>
<!-- handler for authorization failure. Will redirect to the login page. -->
<beans:bean id="myAccessDeniedHandler" class="org.springframework.security.web.access.AccessDeniedHandlerImpl">
<beans:property name="errorPage" value="/index" />
</beans:bean>
note that the loginUrlAuthenticationEntryPoint is actually not a part of the solution, it's the access-denied-handler.
my mvc-config.xml still has the SimpleMappingExceptionResolver, but with no defaultErrorView configured. If I were to continue with this path, I would probably implement my own SimpleMappingExceptionResolver that would let Authentication and Authorization excpetions pass through, OR configure it in the SimpleMappingExceptionResolver instead.
The killer in this deal is that I haven't found a way to configure the requires-channel="https" from the intercept-url through an annotation, so I'll be putting it in the xml configuration file for now anyway.

You can customize your error handling by overriding the security entry point. All exceptions that happen in the filter chain (defined by the mapping you define in the web.xml file) for secure objects get caught and can be handled there. If they are not handled then the ExceptionTranslationFilter will take over.
You can define your own entry point like this:
public class CustomAuthenticationEntryPoint implements AuthenticationEntryPoint {
#Override
public void commence(HttpServletRequest request, HttpServletResponse response, org.springframework.security.core.AuthenticationException authException) throws IOException, ServletException {
if (authException != null) {
// you can check for the spefic exception here and redirect like this
response.sendRedirect("403.html");
}
}
}
You can specify this as your entry point by setting this as you entry point in the xml config file:
<http entry-point-ref="customAuthenticationEntryPoint">
...
</http>
In your specific case the PreInvocationAuthorizationAdviceVoter will be invoked by whatever AccessDecisionManager you specify in your configuration (typically it is one of the following: AffirmativeBased, ConsensusBased, or UnanimousBased). You will see that these Voters throw the AccessDeniedException which you can specifically catch and handle in your entry point.
Grant

how to display custom error message in jsp for spring security auth exception

I want to display custom error message in jsp for spring security authentication exceptions.
For wrong username or password,
spring displays : Bad credentials
what I need : Username/Password entered is incorrect.
For user is disabled,
spring displays : User is disabled
what I need : Your account is diabled, please contact administrator.
Do I need to override AuthenticationProcessingFilter just for this ? or else can I do something in jsp itself to find the authentication exception key and display different message

Redefine the properties in messages.properties inside spring security jar. For example add to the classpath myMessages.properties and add a message source to the context:
AbstractUserDetailsAuthenticationProvider.badCredentials=Username/Password entered is incorrect.
AbstractUserDetailsAuthenticationProvider.disabled=Your account is diabled, please contact administrator.
At Salvin Francis:
Add myMessages.properties to the WAR file inside WEB-INF/classes.
Add this bean to spring context config file
Message Source Bean
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basenames">
<list>
<value>myMessages</value>
</list>
</property>
</bean>

After adding the "messageSource" bean, I had problems to get the Error Message work with the CookieLocaleResolver because the DispatcherServlet (which does use this for your application automatically) is invoked after the Security.
See: http://static.springsource.org/spring-security/site/docs/3.1.x/reference/springsecurity-single.html#localization
My Solution was a custom Filter which sets the LocalContextHolder:
public class LocaleContextFilter extends OncePerRequestFilter {
private LocaleResolver localeResolver;
public void setLocaleResolver(LocaleResolver localeResolver) {
this.localeResolver = localeResolver;
}
#Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
FilterChain filterChain) throws ServletException, IOException {
// store Local into ThreadLocale
if (this.localeResolver != null) {
final Locale locale = this.localeResolver.resolveLocale(request);
LocaleContextHolder.setLocale(locale);
}
try {
filterChain.doFilter(request, response);
} finally {
LocaleContextHolder.resetLocaleContext();
}
}
}
And the Spring Security Context configuration:
<http use-expressions="true">
<custom-filter ref="localeContextFilter" after="FIRST" />
.....
</http>
<beans:bean id="localeContextFilter" class="at.telekom.ppp.util.opce.fe.interceptor.LocaleContextFilter" >
<beans:property name="localeResolver" ref="localeResolver" /><!-- e.g.: CookieLocaleResolver -->
</beans:bean>
I hope this helps others which has this problem.

Here is a JSP EL fix for this. More of a hack than an elegant solution, but gets the job done quick and dirty. Caveat- this is not i18n safe! Only English.
This requires the functions tag library:
<%# taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
And the replace code:
${fn:replace(SPRING_SECURITY_LAST_EXCEPTION.message, 'Bad credentials', 'Username/Password are incorrect')}

I am new to spring, but try this at the server:
throw new BadCredentialsException("This is my custom message !!");
Of course you need a class that is an authentication provider for this to work.