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Spring Security Custom Auth Manager approach

I would like to access the http request, specifically auth header in AuthenticationManager.authenticate() context.
Requirement is to authenticate a custom token. There is an external library which does that and so I don't have the luxury to read out principal from the token. Hence, in the custom filter, I am returning the full token in the getPreAuthenticatedPrincipal() method. This seems borderline incorrect and I would like to not pass the token pretending it to be principal.
Is there any way I can get it without violating any framework constraints?
Or is there a better way to handle the scenario which I'm trying to achieve?
Here's the config class:
#Configuration
#EnableWebSecurity(debug = true)
#EnableGlobalMethodSecurity(securedEnabled = true)
public class SecurityConfig extends WebSecurityConfigurerAdapter {
protected void configure(HttpSecurity httpSecurity) throws Exception{
CustomTokenFilter customTokenFilter = new CustomTokenFilter();
customTokenFilter.setAuthenticationManager(new CustomAuthenticationMgr());
httpSecurity
// csrf etc etc
.addFilter(customTokenFilter)
.authorizeRequests()
.mvcMatchers("/users/**")
.authenticated()
.and()
.authorizeRequests()
.mvcMatchers("/other-api/**")
.permitAll()
.and()
.httpBasic();
}
Here's the custom token filter class:
public class CustomTokenFilter extends AbstractPreAuthenticatedProcessingFilter {
#Override
protected Object getPreAuthenticatedPrincipal(HttpServletRequest request) {
String authorization = request.getHeader("authorization");
if(authorization.indexOf("Custom") == 0){
return Map.of("Custom",authorization.split(" ")[1]);
}
return null;
}
#Override
protected Object getPreAuthenticatedCredentials(HttpServletRequest request) {
return "";
}
}
And finally, the custom authentication manager class:
public class CustomAuthenticationMgr implements AuthenticationManager {
#Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
Map<String,String> map = (Map) authentication.getPrincipal();
String token = map.get("Custom");
// Custom validation - checking length here just to simplify
if(token.length() > 0)
authentication.setAuthenticated(true);
return authentication;
}
}
Version: Spring Boot 2.6.7 (transitive: spring-core 5.3.19)
Constraints: Cannot upgrade to other versions at the moment
Thanks in advance!

You're right, this isn't a good way to do it. (It's great you noticed -- too few people care whether their code is idiomatic.)
A better way would be to start by writing your own filter that actually just... does the authentication. You can extend OncePerRequestFilter rather than something more specific. That's what Spring Security itself does, both for basic authentication (BasicAuthenticationFilter) and for OAuth bearer tokens (BearerTokenAuthenticationFilter). You may want to take a careful look at the code for BearerTokenAuthenticationFilter since the problem it solves is very similar to yours. (I wouldn't extend it, though, since it's very clearly intended to do OAuth specifically. I wouldn't straight up copy the code either -- it's fairly simple as Spring Security filters go but probably still does more than you need. Try to understand the code instead; that will help a lot with your understanding of Spring Security in general.)
Okay, so you have a filter which looks a lot like BearerTokenAuthenticationFilter. That is, it contains an AuthenticationManager and its doFilter method consists of extracting the token from the request, passing that into the AuthenticationManager and then doing some SecurityContext-related stuff. Except, problem: AuthenticationManager.authenticate() expects an Authentication, not a String, and the token is a String.
The solution is to write a wrapper object for your token which implements Authentication. You can do this a couple of ways. Personally, what I'd do is use two classes: one which you pass into AuthenticationManager.authenticate(), and one which you get back. So we have, say, CustomTokenAuthenticationRequest implements Authentication and CustomTokenAuthentication implements Authentication. Both are immutable.
CustomTokenAuthenticationRequest basically just contains the token; its isAuthenticated() is return false, its getPrincipal() returns the token and its getCredentials() also returns the token. This is essentially what Spring Security itself does with BearerTokenAuthenticationToken.
CustomTokenAuthentication, on the other hand, probably contains a UserDetails of some sort; its isAuthenticated() is return true, its getName() is a username or user id or something, etc.
Now you need to teach the AuthenticationManager to authenticate CustomTokenAuthenticationRequests. The way to do this isn't to implement AuthenticationManager, it's to implement AuthenticationProvider. So you write a class that looks roughly like
public class CustomTokenAuthenticationProvider implements AuthenticationProvider {
#Override
public Authentication authenticate(Authentication a) {
String token = ((CustomTokenAuthenticationRequest) a).getToken();
if (/* the token is valid */) {
CustomTokenAuthentication returnValue = // whatever you want it to be
return returnValue;
}
throw new BadCredentialsException("Invalid token");
}
#Override
public boolean supports(Class<?> authClass) {
return authClass == CustomTokenAuthenticationRequest.class;
}
}
Finally, wire it all up. Add the authentication provider to your HttpSecurity using its authenticationProvider() method. (If you do this, and you don't change the default authentication manager configuration, authenticationProvider() results in your authentication provider getting added to an AuthenticationManager which Spring Security configures for you -- an instance of ProviderManager.) Add the filter using addFilterAt(BasicAuthenticationFilter.class). Also, don't call httpBasic() because this adds a BasicAuthenticationFilter which I am guessing you don't want. Or maybe you want basic authentication and also your custom token authentication? But you didn't say that. If you do want both, you'll want to add your filter with addFilterBefore or addFilterAfter, and you need to think about ordering. Generally filter ordering is important in Spring Security.
I glossed over a lot of stuff here, barely gave you any code, and still wrote something of blog post length. Spring Security is very complex, and the thing you're trying to do isn't easily done in an idiomatic manner if you don't have much experience. I highly recommend just reading the Spring Security reference documentation from start to finish before you try implementing any of my suggestions. You'll also need to read quite a lot of Javadoc and tutorials and/or framework code. If there's something specific you want to follow up on I might respond to a comment, but I don't promise it; I had to do some research for this answer and have already spent more time on it than I planned to.

you should look spring-security-lambda-dsl,add filter,add auth provider

How to read/write session attribute in Spring Cloud Gateway?

I'm trying to persist user in http session and verify authentication request inside Gateway by using a custom filter. I found a similar question too:
SecurityConfig:
#Configuration
public class SecurityConfig {
#Bean
public SecurityWebFilterChain securityWebFilterChain(
ServerHttpSecurity http,
MyAuthenticationFilter myAuthenticationFilter
) {
http
.csrf()
.disable()
.authorizeExchange()
.pathMatchers("/**")
.permitAll()
.and()
.addFilterAt(myAuthenticationFilter, SecurityWebFiltersOrder.FIRST); // custom filter
return http.build();
}
MyAuthenticationFilter:
#Component
public class MyAuthenticationFilter implements WebFilter {
#Override
public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
exchange.getSession().map(
session -> {
session.getAttributes().put("userId", "id123");
// It does not print anything
System.out.println("userId in session: " + session.getAttribute("userId"));
return session;
}
);
return chain.filter(exchange);
}
}
By adding a custom filter, and attempting to read/write session attribute, as I observed in debug mode, the function inside map() never gets executed, and nothing gets print out in the terminal. (Unsurprisingly, downstream service cannot read userId from session even though both gateway and service share the same session).
Why is it not working? Here's a minimal reproduced version: Github repo, please take a look.

Found a workaround:
By setting up a servlet application as a downstream service that does authorization, and then reading/writing session inside the "authorization service" will be relatively easier (since the gateway and the direct downstream service will be sharing the same session).
As to the whole authentication/authorization part in this microservice architecture, I found out that using JWT is more preferable, and it's recommended that it should be stateless in between services, while gateway can be stateful, so as to share session with the said "authorization service".
A great answer explaining JWT implementation visually.

How to create a custom authentication filter in Spring Security?

I'm trying to create a custom Spring Security Authentication Filter in order to implement a custom authentication scheme. I've spent a couple hours reading up on Spring Security, but all of the guides I've found explain how to configure basic setups; I'm trying to write a custom setup, and I'm having trouble finding documentation on how to do so.
For the sake of example, lets say that my custom authentication scheme is as follows:
If the client provides a "foo_username" header and a "foo_password" header in the http request (both unencrypted for the sake of example), then my custom filter needs to construct a UsernamePasswordAuthenticationToken. Of course if the password is wrong, that's an authentication error. If either header is missing that's an authentication error. If both headers are missing, I want to delegate down the filter chain without changing anything.
That seems simple enough in theory, but I don't know how to implement that in Spring. Am I intended to check the password against the DB myself? or is that the reponsibility of the UserDetailsPasswordService? Am I intended to modify the SecurityContextHolder.getContext().authentication field myself? What responsibilities do I delegate to the AuthenticationManager? Which exceptions do I throw when authentication fails in various ways? Do I implement Filter, OncePerRequestFilter, or AbstractAuthenticationFilter? Is there any documentation on how to do all this???
Admittedly, this is a duplciate of How to create your own security filter using Spring security?, but I'm not him, and he got no answers.
Thanks for the help!

Edit: This is the not best way to do things. It doesn't follow best practices. I haven't had time to udpate this answer with an example that does follow best practices.
As others have pointed out, it's better to use Basic auth or OAuth2, both of which are built into Spring. But if you really want to implement a custom filter, you can do something like this. (Please correct me if I'm doing this wrong.) But don't do this exactly. This is not a very secure example; it's a simple example.
class CustomAuthenticationFilter(val authManager: AuthenticationManager) : OncePerRequestFilter() {
override fun doFilterInternal(request: HttpServletRequest,
response: HttpServletResponse,
chain: FilterChain) {
val username = request.getHeader("foo_username")
val password = request.getHeader("foo_password")
if(username==null && password==null){
// not our responsibility. delegate down the chain. maybe a different filter will understand this request.
chain.doFilter(request, response)
return
}else if (username==null || password==null) {
// user is clearly trying to authenticate against the CustomAuthenticationFilter, but has done something wrong.
response.status = 401
return
}
// construct one of Spring's auth tokens
val authentication = UsernamePasswordAuthenticationToken(username, password, ArrayList())
// delegate checking the validity of that token to our authManager
val userPassAuth = this.authManager.authenticate(authRequest)
// store completed authentication in security context
SecurityContextHolder.getContext().authentication = userPassAuth
// continue down the chain.
chain.doFilter(request, response)
}
}
Once you've created your auth filter, don't forget to add it to your HttpSecurity config, like this:
override fun configure(http: HttpSecurity?) {
http!!.addFilterBefore(CustomAuthenticationFilter(authenticationManager()), UsernamePasswordAuthenticationFilter::class.java)
}

I think what you want to do is implement AuthenticationProvider. It allows your code to explicitly manage the authentication portion. It has a fairly simple method signature to implement as well.
public class YourAuthenticationProvider implements AuthenticationProvider {
#Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
String username = authentication.getName();
String password = authentication.getCredentials().toString();
...
return new UsernamePasswordAuthenticationToken(principal, password, principal.getAuthorities())
}
#Override
public boolean supports(Class<?> authentication) {
return authentication.equals(UsernamePasswordAuthenticationToken.class);
}
}
You can register it by adding it to the AuthenticationManagerBuilder in a config that extends WebSecurityConfigurerAdapter
#Configuration
class SecurityConfig extends WebSecurityConfigurerAdapter {
#Override
protected void configure(AuthenticationManagerBuilder auth) {
AuthenticationProvider provider= new YourAuthenticationProvider();
auth.authenticationProvider(provider);
}
}

spring security manual login best practice

I'm using spring security to implement a programmatic, manual user login. I have a scenario where I have positively established the user's identity, and wish to log them in. I don't know their password, and so can't use the regular login code path where you submit a form to a url, which spring intercepts via a servlet Filter, doing all of it's auth+session magic.
I've searched, and it seems most people create their own Authentication object, and then tell spring about via:
PreAuthenticatedAuthenticationToken authentication = new PreAuthenticatedAuthenticationToken(user, "", user.getAuthorities());
SecurityContextHolder.getContext().setAuthentication(authentication);
Indeed, this works. Spring even puts it into the session for me, making subsequent http requests maintain their auth status.
However, I feel like this is a dirty hack. I'll present some details that I hope will give concrete examples of the problems associated with using setAuthentication() inside a controller to achieve a manual login:
To give an idea, my config is:
httpSecurity
.authorizeRequests()
.antMatchers("/test/**").permitAll()
.antMatchers("/admin/**", "/api/admin/**").hasRole("USER_SUPER_ADMIN")
.and()
.formLogin()
.loginPage("/sign-in?sp")
.loginProcessingUrl("/api/auth/sign-in")
.successHandler(createLoginSuccessHandler())
.failureHandler(createLoginFailureHandler())
.permitAll()
.and()
.logout()
.logoutUrl("/api/auth/sign-out")
.logoutSuccessHandler(createLogoutSuccessHandler())
.and()
.sessionManagement()
.maximumSessions(1)
.maxSessionsPreventsLogin(true)
.sessionRegistry(sessionRegistry)
;
Key points in the above config:
I use custom success and failure handlers for the form login
I want to config behavior for max concurrent sessions per user
I want to maintain spring's default session fixation protection (changing session id upon login).
I want to use a session registry
... more of these session/login functionalities, had I chosen to config it.
I stepped through the code to see how spring processes a form login. As expected, Spring does all the session/login functionalities that my HttpSecurity config told it to do when I use the form login. But, when I do my own custom/manual login via SecurityContextHolder.getContext().setAuthentication(), it does NONE of those functionalities. This is because spring does all of it's session/login functionalities stuff inside of a servlet Filter, and my programmatic code can't really call a Filter. Now, I can attempt to add the missing functionalities myself, duplicating their code: I see that the spring Filter uses: ConcurrentSessionControlAuthenticationStrategy, ChangeSessionIdAuthenticationStrategy, and RegisterSessionAuthenticationStrategy. I can create these objects myself, configure them, and call them after my custom login. But, that's really lame to duplicate all that spring code. Furthermore, there's still other behaviors I'm missing - I noticed that when using the form login code path, that spring triggers some login events which don't get triggered when I do my custom login. And there's probably other stuff that I'm missing or don't understand. The whole process is pretty complicated, and I feel like there's a high chance of introducing bugs if this isn't done right, not to mention that library updates would be a pain if I started duplicating spring code.
So, I feel like I'm approaching this from the wrong way. Should I be using a different strategy, so that I'm not bypassing so much of the stuff that spring does for me? Maybe I should try to make my own AuthenticationProvider to accomplish this custom login?
*To clarify, my code more or less works. But, I feel like I accomplished it using a poor strategy because I had to write code duplicating a lot of stuff that spring does for me. Further, my code doesn't perfectly replicate what spring does, making me wonder what negative implications might result. There must be a better way to programatically achieve login.

I wanted to elaborate on how I implemented the advice of dur. In my scenario, I only used a custom AuthenticationProvider.
Instead of creating a custom servlet Filter, such as extending AbstractAuthenticationProcessingFilter, which seemed like a lot of work, I choose to instead use the following strategy:
At the point in my code where I was confident that I had identified the user, and wanted them to be "logged in", I stuck a flag in the user's session, marking that they should be logged in on the next request, along with any other identity/bookkeeping info I needed, such as their username.
Then, I told the browser client to make an http post to the loginProcessingUrl (the same one I configured spring security to use for form-based login), telling them to send the standard username and password form params, although they don't need to send real values - dummy values like foo are fine.
When the user makes that post request (eg to /login), spring will invoke my custom AuthenticationProvider, which will look in the user's session to check for the flag, and to gather the username. Then it will create and return an Authentication object, such as PreAuthenticatedAuthenticationToken, which identifies the user.
Spring will handle the rest. The user is now logged in.
By doing it this way, you stay within the "normal" way of doing logins, and so spring will still automatically:
Call any custom success and failure handlers you configured for the form login, which is nice if you use that place to do certain things on login, like query or update a db.
It will respect any max concurrent sessions per user settings that you may be using.
You get to keep spring's default session fixation attack protection (changing session id upon login).
If you set a custom session timeout, eg via server.session.timeout in a properties file, spring will use it. There's probably other session config attributes that are done at this time too.
If you enabled spring's "remember me" functionality, it will work.
It will fire a login event, which is used for other spring components, such as storing the user's session in a SessionRegistry. I think the events are also used by other parts of spring, such as the actuator, and for auditing.
When I first tried just doing the typically recommended SecurityContextHolder.getContext().setAuthentication(authentication) to login my user, instead of the custom AuthenticationProvider, none of the above bullets were done for me, which can utterly break your app... or cause subtle security bugs - neither are good.
Here's some code to help solidify what I said:
Custom AuthenticationProvider
#Component
public class AccountVerificationAuthenticationProvider implements AuthenticationProvider {
#Autowired
private AppAuthenticatedUserService appAuthenticatedUserService;
#Autowired
private AuthService authService;
#Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
// This will look in the user's session to get their username, and to make sure the flag is set to allow login without password on this request.
UserAccount userAccount = authService.getUserAccountFromRecentAccountVerificationProcess();
if (userAccount == null) {
// Tell spring we can't process this AuthenticationProvider obj.
// Spring will continue, and try another AuthenticationProvider, if it can.
return null;
}
// A service to create a custom UserDetails object for this user.
UserDetails appAuthenticatedUser = appAuthenticatedUserService.create(userAccount.getEmail(), "", true);
PreAuthenticatedAuthenticationToken authenticationToken = new PreAuthenticatedAuthenticationToken(appAuthenticatedUser, "", appAuthenticatedUser.getAuthorities());
authenticationToken.setAuthenticated(true);
return authenticationToken;
}
#Override
public boolean supports(Class<?> authentication) {
return authentication.equals(UsernamePasswordAuthenticationToken.class);
}
}
Config spring security to use the provider
// In your WebSecurityConfigurerAdapter
#Configuration
#EnableWebSecurity
public class AppLoginConfig extends WebSecurityConfigurerAdapter {
#Autowired
private AccountVerificationAuthenticationProvider accountVerificationAuthenticationProvider;
#Autowired
private ActiveDirectoryLdapAuthenticationProvider activeDirectoryLdapAuthenticationProvider;
#Override
protected void configure(AuthenticationManagerBuilder authenticationManagerBuilder) throws Exception {
// Spring will try these auth providers in the order we register them.
// We do the accountVerificationAuthenticationProvider provider first, since it doesn't need to do any slow IO to check,
// so it's very fast. Only if this AuthenticationProvider rejects (which means this http request is not for programmatic login), will spring then try the next AuthenticationProvider in the list.
authenticationManagerBuilder
.authenticationProvider(accountVerificationAuthenticationProvider)
// I'm using ActiveDirectory / LDAP for when a user logs in via entering a user + password via the html form, but whatever you want to use here should work.
.authenticationProvider(activeDirectoryLdapAuthenticationProvider);
}
#Override
protected void configure(HttpSecurity httpSecurity) throws Exception {
...
}
}

For custom web authentication you should implement combination of a custom authentication filter (for example AbstractAuthenticationProcessingFilter or just GenericFilterBean), a custom authentication provider (AuthenticationProvider) or/and custom authentication token (AbstractAuthenticationToken).
For example, see source of Spring Security Kerberos.
See also:
The AuthenticationManager, ProviderManager and AuthenticationProvider

Multiple rules for the same url?

I've a use case where i need an endpoint
/api/v1/resources
that should be public and private at the same time. What does it mean?
If basic authentication is provided, i would like to perform the authentication as usual, that stores the stuff in SecurityContextHolder.
On the other hand, if there is no authentication provided, i would also like to allow the request.
I tried a bunch of stuff overriding
#Override
protected void configure(HttpSecurity http) throws Exception {
without luck. if i do
http.authorizeRequests()
.antMatchers("/api/v1/resources").permitAll()
and i call the endpoint with basic auth, it obviously ignores and despite the request go ahead, i don't have the auth information that i need to forward to another service.
if i do
http.authorizeRequests()
.anyRequest().authenticated()
.and()
.httpBasic();
i get that endpoint working and having the basic auth result stored so i can forward the information, but then i get 401 when calling it without authentication.
Is there a way I can apply multiple rules to the same endpoint? Or something similar to achieve this?
Thanks in advance.
EDIT:
For now, the only way i found to achieve this was adding a custom filter before the whole chain that checks for the Authorization Header, and if there no header, i inject the header in the request as an attibute(i need to wrap the request object to override the getHeader method to search for attributes if the header is missing so i can retrieve that header afterwards).