JWT for Resetting password with mfa - spring-security

I'm working on authorization-server and identity management project. Part of it is to secure the reset-password endpoint with MFA.
The MFA logic exists in the authorization-server project,
However, the reset-password itself is in the identity management project
I thought that after the user completes MFA, there are two ways for the endpoint to validate that the user has privilege to reset the password:
Add a ROLE_PASSWORD_RESET in the authorities role the when the reset-password endpoint gets called I can check the database and if the role exists I would reset the password
Second way is to create a JWT that expires after short time. Then the front end would pass this JWT to password rest endpoint which decodes the JWT and reset password if the JWT is valid.
Decoded JWT looks like this
{
"exp": 1540811250,
"user_name": "blah",
"authorities": [
"ROLE_PASSWORD_RESET"
],
"jti": "fdbb528a-39b4-46f7-a336-79b5caa7439f",
"client_id": "04a14e01-f303-41ca-8a7f-aa62e38a8261"
}
And this is the code that produces the JWT at the end of MFA process
if (authentication instanceof AnonymousAuthenticationToken) {
final String username = mfaVerificationRequest.getUsername();
final Collection <GrantedAuthority> authorities = AuthorityUtils.createAuthorityList(ROLE_PASSWORD_RESET);
final Authentication authenticationToken = new UsernamePasswordAuthenticationToken(username, null, authorities);
final String clientId = request.getParameter(OAuth2Utils.CLIENT_ID);
final ClientDetails clientDetails = clientDetailsService.loadClientByClientId(clientId);
final OAuth2Request auth2Request = new OAuth2Request(null, clientDetails.getClientId(), authorities, true, clientDetails.getScope(), null, null, null, null);
final OAuth2Authentication oAuth2Authentication = new OAuth2Authentication(auth2Request, authenticationToken);
DefaultOAuth2AccessToken.valueOf(createOauth2AccessTokenMap(clientDetails.getScope()));
final OAuth2AccessToken enhancedAuth2AccessToken = jwtAccessTokenConverter.enhance(accessToken, oAuth2Authentication);
response.setStatus(SC_OK);
response.setContentType(MediaType.APPLICATION_JSON);
response.setCharacterEncoding(StandardCharsets.UTF_8.name());
mapper.writeValue(response.getWriter(), enhancedAuth2AccessToken);
return;
}
I believe the second approach is a hacky one because:
Tokens (from what I understand) are meant for authenticated users but when the user is trying to reset the password, there are not authenticated user in the security context of authorization-server
Am I twisting spring security to do something it was not meant to do?
Any advice on a cleaner way?

Related

jhipster Reload OIDC token after modifying user last name with keycloak rest admin API (Oauth2)

I have Jhipster running with Oauth2 + Keycloak.
I have a use case where I need to update user last and first name from the Jhipster React UI, so I used the Keycloak admin client via a service account to update user attributes in Keycloak.
The problem is that the information needs to be re-fetched to the OIDC token to let the user see the changes immediately. (similar issue here: https://github.com/jhipster/generator-jhipster/issues/7398 )
Is there any suggestion how to setup Spring Security to be able to re-fetch/refresh my token with the latest information form Keycloak, or any explicit call to do it?
Thanks for the answears!
So from workflow point of view I was able to solve the problem by:
Changing the data via Keycloak admin client
Change the data in the Spring Security Context
I had a wrong assumption about spring security that it validates the token data against the actual token stored in the context on every call. It turned out the spring security has no problem by changing the data in the context, so on the next login I can get a valid token what is inline with the actual data.
This is the code I was able to change the context with:
public void updateUserRole(AbstractAuthenticationToken abstractAuthenticationToken)
{
SecurityUtils.getCurrentUserLogin().flatMap(userRepository::findOneByLogin)
.ifPresent(user -> {
Set<Authority> authorities = user.getAuthorities();
Authority authority = new Authority();
authority.setName(AuthoritiesConstants.USER);
authorities.remove(AuthoritiesConstants.INVITED);
authorities.add(authority);
user.setAuthorities(authorities);
this.clearUserCaches(user);
log.debug("Changed Information for User: {}", user);
});
Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
List<GrantedAuthority> authorities = List.of(new SimpleGrantedAuthority(AuthoritiesConstants.USER));
Map<String, Object> claims = ((OidcIdToken)((DefaultOidcUser)((OAuth2AuthenticationToken)abstractAuthenticationToken).getPrincipal()).getIdToken()).getClaims();
String userNameKey = ((OAuth2AuthenticationToken)authentication).getAuthorizedClientRegistrationId();
String tokenValue = ((OidcIdToken) ((DefaultOidcUser) ((OAuth2AuthenticationToken) abstractAuthenticationToken).getPrincipal()).getIdToken()).getTokenValue();
Instant issuedAt = ((OidcIdToken) ((DefaultOidcUser) ((OAuth2AuthenticationToken) abstractAuthenticationToken).getPrincipal()).getIdToken()).getIssuedAt();
Instant expiresAt = ((OidcIdToken) ((DefaultOidcUser) ((OAuth2AuthenticationToken) abstractAuthenticationToken).getPrincipal()).getIdToken()).getExpiresAt();
OidcIdToken oidcIdToken = new OidcIdToken(tokenValue, issuedAt, expiresAt, claims);
DefaultOidcUser user = new DefaultOidcUser(authorities, oidcIdToken, "name");
OAuth2AuthenticationToken oAuth2AuthenticationToken = new OAuth2AuthenticationToken(user, authorities, userNameKey);
SecurityContextHolder.getContext().setAuthentication(oAuth2AuthenticationToken);
}

Spring security implementation with AWS congnito authentication on front end

I separate my application into 2 parts:
Front end : Vue js and connected with AWS congnito for login feature (email/pw or google social login).
Back end : Spring boot Restful. User information stored in database (a unique id from congnito as primary key.)
My flow of authentication
User redirected to congnito and login. congnito will return a unique id and JWT.
Front end passes the unique id and JWT to back end controller.
backend validate JWT and return user information from DB
My question is:
Is this a bad practice to authenticate on front end and pass data to back end for spring security? If so, may I have any suggestion to change my implementation flow?
To call AuthenticationProvider.authenticate, a Authentication consist username (in my case, the unique id from cognito) and password is needed (UsernamePasswordAuthenticationToken). Are there any implementation to set only username? or it is fine to set password as empty string?
// controller
public String login(HttpServletRequest req, String cognitoId, String jwt) {
// check JWT with AWS
if(!AwsJwtChecker(cognitoId, jwt))
return createErrorResponseJson("invalid jwt");
UsernamePasswordAuthenticationToken authReq
= new UsernamePasswordAuthenticationToken(cognitoId, "");
Authentication auth = authManager.authenticate(authReq);
SecurityContext sc = SecurityContextHolder.getContext();
sc.setAuthentication(auth);
HttpSession session = req.getSession(true);
session.setAttribute(SPRING_SECURITY_CONTEXT_KEY, sc);
MyUser user = userRepository.selectUserByCognitoId(cognitoId);
return createLoginSuccessResponse(user);
}
// web config
#Component
public class CustomAuthenticationProvider implements AuthenticationProvider {
#Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
String cognitoId = authentication.getName();
// check user exist in db or not
MyUser user = userRepository.selectUserByCognitoId(cognitoId);
if (user != null) {
return new UsernamePasswordAuthenticationToken(username, "", user.getRoles());
} else {
throw new BadCredentialsException("Authentication failed");
}
}
#Override
public boolean supports(Class<?>aClass) {
return aClass.equals(UsernamePasswordAuthenticationToken.class);
}
}
Is this a bad practice to authenticate on front end and pass data to back end for spring security? If so, may I have any suggestion to change my implementation flow?
No, in fact it's best practice. JWT is exactly for that purpose: You can store information about the user and because of the signature of the token, you can be certain, that the information is trustworthy.
You don't describe what you are saving in the database, but from my perspective, you are mixing two authentication methods. While it's not forbidden, it might be unnecessary. Have you analysed your token with jwt.io? There are many information about the user within the token and more can be added.
Cognito is limited in some ways, like number of groups, but for a basic application it might be enough. It has a great API to manage users from within your application, like adding groups or settings properties.
You don't describe what you do with the information that is returned with 3). Vue can too use the information stored in the jwt to display a username or something like that. You can decode the token with the jwt-decode library, eg, and get an object with all information.
To call AuthenticationProvider.authenticate...
Having said that, my answer to your second question is: You don't need the whole authentication part in you login method.
// controller
public String login(HttpServletRequest req, String cognitoId, String jwt) {
// check JWT with AWS
if(!AwsJwtChecker(cognitoId, jwt))
return createErrorResponseJson("invalid jwt");
return userRepository.selectUserByCognitoId(cognitoId);
}
This should be completely enough, since you already validate the token. No need to authenticate the user again. When spring security is set up correctly, the jwt will be set in the SecurityContext automatically.
The problem I see with your implementation is that anyone could send a valid jwt and a random cognitoId and receive user information from the database. So it would be better to parse the jwt and use something from within the jwt, like username, as identifier in the database. The token can't be manipulated, otherwise the validation fails.
public String login(String jwt) {
// check JWT with AWS
if(!AwsJwtChecker(jwt))
return createErrorResponseJson("invalid jwt");
String identifier = getIdentifier(jwt);
return userRepository.selectUserByIdentifier(identifier);
}

validate access token with user name in Oauth2

I'm trying to implement OAuth2 authentication for my SPA application. am facing one issue, For example there is two users, user1 and user2 both are logged in . when the user1 trying to use user2 access token, user1 can access . i don't know how to secure access token.
Each time when a user logged in using oauth2 authentication, it associates the user-id of the newly logged in user with an unique access_token, you can get that user_id, and in turn map it with the user_id of current logged in user to find out if its the user is using his own access_token.
I have find out the solution.
To customizing the access token we can secure the users access token.
i have customize the access token using Token enhancer.
Code will be like below
#Primary
#Bean
public DefaultTokenServices defaultTokenServices() {
DefaultTokenServices defaultTokenServices = new DefaultTokenServices();
defaultTokenServices.setTokenStore(tokenStore());
defaultTokenServices.setTokenEnhancer(tokenEnhancer());
defaultTokenServices.setSupportRefreshToken(true);
return defaultTokenServices;
}
and custom enhancer will be like
public OAuth2AccessToken enhance(OAuth2AccessToken accessToken, OAuth2Authentication authentication) {
AppUserDetails appUserDetails = (AppUserDetails) authentication.getPrincipal();
final Map<String, Object> additionalInfo = new HashMap<>();
String encodedBytes = Base64.getEncoder().encodeToString(appUserDetails.getIdUser().toString().getBytes());
additionalInfo.put("authorities", appUserDetails.getAuthorities());
additionalInfo.put("username", appUserDetails.getUsername());
additionalInfo.put("idUser", encodedBytes);
((DefaultOAuth2AccessToken) accessToken).setAdditionalInformation(additionalInfo);
return accessToken;
}
in other method i have decode the customize access token.
Also i have used AuthorizationServerEndpointsConfigurer
#Override
//Configure the properties and enhanced functionality of the Authorization Server endpoints.
public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
endpoints.tokenStore(tokenStore()).tokenEnhancer(tokenEnhancer()).authenticationManager(authenticationManager);
}

Integrate Spring Security OAuth2 and Spring Social

I'm working with a Spring Boot + Spring Security OAuth2 application that I believe was inspired by examples from Dave Syer. The application is configured to be an OAuth2 authorization server, with a single public client using the Resource Owner Password Credentials flow. A successful token is configured to be a JWT.
The public Angular client sends a POST request to /oauth/token with a basic auth header containing the client id and secret (this was the easiest way to get the client to authenticate, even though the secret is not private). The body of the request contains username, password, and grant type of "password".
In addition to being an authentication server, the application is a RESTful resource server for users, teams, and organizations.
I'm trying to add an additional SSO authentication flow using Spring Social. I've got Spring Social configured to authenticate through external providers via /auth/[provider]; however, following requests no longer have the SecurityContext correctly set. Possibly, Spring Security OAuth server or client is overriding the SecurityContext?
If I can get the SecurityContext correctly set after the Spring Social flow, I've got a new TokenGranter that allows a new grant type of "social" that would check the SecurityContextHolder for the pre authenticated user.
I'm interested in both a solution to my specific problem with the SecurityContext (I believe it's an issue with Spring OAuth + Social integration), or a different approach for authenticating with external providers and getting a valid JWT from our own auth server.
Thanks!
I had a similar problem on a JHipster-generated web application. Finally I decided to go with the SocialAuthenticationFilter option from Spring Social (via the SpringSocialConfigurer). After a successful social login, the server automatically generates and returns the "own" access token via redirection to the client app.
Here's my try:
#Configuration
#EnableResourceServer
protected static class ResourceServerConfiguration extends ResourceServerConfigurerAdapter implements EnvironmentAware {
//...
#Inject
private AuthorizationServerTokenServices authTokenServices;
#Override
public void configure(HttpSecurity http) throws Exception {
SpringSocialConfigurer socialCfg = new SpringSocialConfigurer();
socialCfg
.addObjectPostProcessor(new ObjectPostProcessor<SocialAuthenticationFilter>() {
#SuppressWarnings("unchecked")
public SocialAuthenticationFilter postProcess(SocialAuthenticationFilter filter){
filter.setAuthenticationSuccessHandler(
new SocialAuthenticationSuccessHandler(
authTokenServices,
YOUR_APP_CLIENT_ID
)
);
return filter;
}
});
http
//... lots of other configuration ...
.apply(socialCfg);
}
}
And the SocialAuthenticationSuccessHandler class:
public class SocialAuthenticationSuccessHandler implements AuthenticationSuccessHandler {
public static final String REDIRECT_PATH_BASE = "/#/login";
public static final String FIELD_TOKEN = "access_token";
public static final String FIELD_EXPIRATION_SECS = "expires_in";
private final Logger log = LoggerFactory.getLogger(getClass());
private final AuthorizationServerTokenServices authTokenServices;
private final String localClientId;
public SocialAuthenticationSuccessHandler(AuthorizationServerTokenServices authTokenServices, String localClientId){
this.authTokenServices = authTokenServices;
this.localClientId = localClientId;
}
#Override
public void onAuthenticationSuccess(HttpServletRequest request,
HttpServletResponse response, Authentication authentication)
throws IOException, ServletException {
log.debug("Social user authenticated: " + authentication.getPrincipal() + ", generating and sending local auth");
OAuth2AccessToken oauth2Token = authTokenServices.createAccessToken(convertAuthentication(authentication)); //Automatically checks validity
String redirectUrl = new StringBuilder(REDIRECT_PATH_BASE)
.append("?").append(FIELD_TOKEN).append("=")
.append(encode(oauth2Token.getValue()))
.append("&").append(FIELD_EXPIRATION_SECS).append("=")
.append(oauth2Token.getExpiresIn())
.toString();
log.debug("Sending redirection to " + redirectUrl);
response.sendRedirect(redirectUrl);
}
private OAuth2Authentication convertAuthentication(Authentication authentication) {
OAuth2Request request = new OAuth2Request(null, localClientId, null, true, null,
null, null, null, null);
return new OAuth2Authentication(request,
//Other option: new UsernamePasswordAuthenticationToken(authentication.getPrincipal(), "N/A", authorities)
new PreAuthenticatedAuthenticationToken(authentication.getPrincipal(), "N/A")
);
}
private String encode(String in){
String res = in;
try {
res = UriUtils.encode(in, GeneralConstants.ENCODING_UTF8);
} catch(UnsupportedEncodingException e){
log.error("ERROR: unsupported encoding: " + GeneralConstants.ENCODING_UTF8, e);
}
return res;
}
}
This way your client app will receive your web app's access token via redirection to /#/login?access_token=my_access_token&expires_in=seconds_to_expiration, as long as you set the corresponding REDIRECT_PATH_BASE in SocialAuthenticationSuccessHandler.
I hope it helps.
First, I would strongly recommend you to move away from the password grant for such a use case.
Public clients (JavaScript, installed applications) cannot keep their client secret confidential, that's why they MUST NOT be assigned one : any visitor inspecting your JavaScript code can discover the secret, and thus implement the same authentication page you have, storing your users passwords in the process.
The implicit grant has been created exactly for what you are doing.
Using a redirection-based flow has the advantage of leaving the authentication mechanism up to the authorization server, instead of having each of your applications have a piece of it : that's mostly the definition of Single Sign On (SSO).
With that said, your question is tightly related to this one I just answered : Own Spring OAuth2 server together with 3rdparty OAuth providers
To sum up the answer :
In the end, it's about how your authorization server secures the AuthorizationEndpoint : /oauth/authorize. Since your authorization server works, you already have a configuration class extending WebSecurityConfigurerAdapter that handles the security for /oauth/authorize with formLogin. That's where you need to integrate social stuff.
You simply cannot use a password grant for what you're trying to achieve, you must have your public client redirect to the authorization server. The authorization server will then redirect to the social login as its security mechanism for the /oauth/authorize endpoint.
I was starting with the good answer of above (https://stackoverflow.com/a/33963286/3351474) however with my version of Spring Security (4.2.8.RELEASE) this fails. The reason is that in org.springframework.security.access.intercept.AbstractSecurityInterceptor#authenticateIfRequired the PreAuthenticatedAuthenticationToken of the answer is not authenticated. Some GrantedAuthorities have to be passed.
In addition sharing the token in an URL parameter is not good, it should always be hidden in an HTTPs payload or header. Instead a HTML template is loaded and the token value is inserted into a ${token} placeholder field.
Here the revised version:
NOTE: The used UserDetails here is implementing org.springframework.security.core.userdetails.UserDetails
#Component
public class SocialAuthenticationSuccessHandler implements AuthenticationSuccessHandler {
#Autowired
private OAuth2TokenStore tokenStore;
#Qualifier("tokenServices")
#Autowired
private AuthorizationServerTokenServices authTokenServices;
public void onAuthenticationSuccess(HttpServletRequest request,
HttpServletResponse response, Authentication authentication)
throws IOException, ServletException {
IClient user = ((SocialUserDetails) authentication.getPrincipal()).getUser();
// registration is not finished, forward the user, a marker interface
// IRegistration is used here, remove this if there no two step approach to
// create a user from a social network
if (user instanceof IRegistration) {
response.sendRedirect(subscriberRegistrationUrl + "/" + user.getId());
}
OAuth2AccessToken token = loginUser(user);
// load a HTML template from the class path and replace the token placeholder within, the HTML should contain a redirect to the actual page, but must store the token in a safe place, e.g. for preventing CSRF in the `sessionStorage` JavaScript storage.
String html = IOUtils.toString(getClass().getResourceAsStream("/html/socialLoginRedirect.html"));
html = html.replace("${token}", token.getValue());
response.getOutputStream().write(html.getBytes(StandardCharsets.UTF_8));
}
private OAuth2Authentication convertAuthentication(Authentication authentication) {
OAuth2Request request = new OAuth2Request(null, authentication.getName(),
authentication.getAuthorities(), true, null,
null, null, null, null);
// note here the passing of the authentication.getAuthorities()
return new OAuth2Authentication(request,
new PreAuthenticatedAuthenticationToken(authentication.getPrincipal(), "N/A", authentication.getAuthorities())
);
}
/**
* Logs in a user.
*/
public OAuth2AccessToken loginUser(IClient user) {
SecurityContext securityContext = SecurityContextHolder.getContext();
UserDetails userDetails = new UserDetails(user);
Authentication authentication = new UsernamePasswordAuthenticationToken(userDetails, "N/A", userDetails.getAuthorities());
securityContext.setAuthentication(authentication);
OAuth2Authentication oAuth2Authentication = convertAuthentication(authentication);
// delete the token because the client id in the DB is calculated as hash of the username and client id (here also also identical to username), this would be identical to the
// to an existing user. This existing one can come from a user registration or a previous user with the same name.
// If a new entity with a different ID is used the stored token hash would differ and the the wrong token would be retrieved
tokenStore.deleteTokensForUserId(user.getUsername());
OAuth2AccessToken oAuth2AccessToken = authTokenServices.createAccessToken(oAuth2Authentication);
// the DB id of the created user is returned as additional data, can be
// removed if not needed
((DefaultOAuth2AccessToken) oAuth2AccessToken).setAdditionalInformation(new HashMap<>());
oAuth2AccessToken.getAdditionalInformation().put("userId", user.getId());
return oAuth2AccessToken;
}
}
Example socialLoginRedirect.html:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Example App</title>
<meta http-equiv="Refresh" content="0; url=/index.html#/home"/>
</head>
<script>
window.sessionStorage.setItem('access_token', '${token}');
</script>
<body>
<p>Please follow this link.</p>
</body>
</html>
The configuration wiring in a WebSecurityConfigurerAdapter:
#Configuration
#EnableWebSecurity
#EnableWebMvc
#Import(WebServiceConfig.class)
public class AuthenticationConfig extends WebSecurityConfigurerAdapter {
#Value("${registrationUrl}")
private String registrationUrl;
#Autowired
private SocialAuthenticationSuccessHandler socialAuthenticationSuccessHandler;
#Value("${loginUrl}")
private String loginUrl;
#Override
protected void configure(HttpSecurity http) throws Exception {
List<String> permitAllUrls = new ArrayList<>();
// permit social log in
permitAllUrls.add("/auth/**");
http.authorizeRequests().antMatchers(permitAllUrls.toArray(new String[0])).permitAll();
SpringSocialConfigurer springSocialConfigurer = new SpringSocialConfigurer();
springSocialConfigurer.signupUrl(registrationUrl);
springSocialConfigurer.postFailureUrl(loginUrl);
springSocialConfigurer
.addObjectPostProcessor(new ObjectPostProcessor<SocialAuthenticationFilter>() {
#SuppressWarnings("unchecked")
public SocialAuthenticationFilter postProcess(SocialAuthenticationFilter filter){
filter.setAuthenticationSuccessHandler(socialAuthenticationSuccessHandler);
return filter;
}
});
http.apply(springSocialConfigurer);
http.logout().disable().csrf().disable();
http.requiresChannel().anyRequest().requiresSecure();
http.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);
}
I implemented spring oauth2 to secure my rest services and additionally add social login and implicit signup for first time login . for user user you can generate the token using username and password only problem with generate the token for social user . for that you have to implement the Filter that will intercept your /oauth/token request before processing . here if you want to generate the the token for social user pass the username and facebook token , here you can use facebook token as password and generate the token for facebook user also . if facebook token updated then you have to write a db trigger also to update you token in user table .... may be it will help you

Does Spring Security gives any such API where I can pass username & password and get the Authentication Object?

Does Spring Security gives any such API where I can pass username & password and it will return either Authentication Object for successful authentication or AuthenticationCredentialsNotFoundException for unsuccessful authentication?
Let me elaborate my requirements:
Our application has a HTTP API(say, /createXXX.do) and the client is hitting this with username, password & other parameters.
Now I want to authenticate + authorize this access (coming from HTTP Hits to my application).
My planned design is like below:
a) I will not restrict access of my HTTP API context(i.e. /createXXX.do)
b) Once the request reached my doGet()/doPost(), I will retrieve the username & password from request and want to use some spring security API like below:
Authentication validateXXXXX(String username, String password)
throws AuthenticationCredentialsNotFoundException;
c) so that this above API internally push these username/password to the existing spring security chain and return me the Authentication Object for successful authentication or AuthenticationCredentialsNotFoundException for unsuccessful authentication.
d) For unsuccessful authentication, I will catch AuthenticationCredentialsNotFoundException and return the HttpServletResponse with AUTHENTICATION_ERROR code.
e) and for successful authetication, based on authiories from Authentication Object, I will allow or return the HttpServletResponse with AUTHORIZATION_ERROR code.
Can anyone know about such spring security API?
Any pointers/suggestion will be highly appreciated.
Thanks.
If you have just one authentication source (only LDAP or only DB) you can configure some implementation of org.springframework.security.authentication.AuthenticationProvider in your security context. Then you can use it:
User user = new User(login, password, true, true, true, true, new ArrayList<GrantedAuthority>());
Authentication auth = new UsernamePasswordAuthenticationToken(user, password,new ArrayList<GrantedAuthority>());
try {
auth = authenticationProvider.authenticate(auth);
} catch (BadCredentialsException e) {
throw new CustomBadCredentialsException(e.getMessage(), e);
}
// but your need to push authorization object manually
SecurityContext sc = new SecurityContextImpl();
sc.setAuthentication(auth);
SecurityContextHolder.setContext(sc);
It is "low level" manipulation. You can use element from Spring Security namespace. It can provide login controller, even login form for you (and it can handle this situation automatically).

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