Spring boot 2 kerberos Authentication

Question

I wanted to know how to use Spring Security Kerberos with Spring Boot 2.0.

We are currently trying to get the SPNego filter to work.

This is the error:

o.s.s.k.w.a.SpnegoAuthenticationProcessingFilter : Negotiate Header was invalid: Negotiate YHoGBisGAQUFAqBwMG6gMDAuBgorBgEEAYI3AgIKBgkqhkiC9xIBAgIGCSqGSIb3EgECAgYKKwYBBAGCNwICHqI6BDhOVExNU1NQAAEAAACXsgjiAwADADUAAAANAA0AKAAAAAYBsR0AAAAPSU5CT01WRDgxMTAzMURCRw==
org.springframework.security.authentication.BadCredentialsException: GSSContext name of the context initiator is null
    at org.springframework.security.kerberos.authentication.sun.SunJaasKerberosTicketValidator$KerberosValidateAction.run(SunJaasKerberosTicketValidator.java:173)
    at org.springframework.security.kerberos.authentication.sun.SunJaasKerberosTicketValidator$KerberosValidateAction.run(SunJaasKerberosTicketValidator.java:153)
    at java.security.AccessController.doPrivileged(Native Method)

Currently we are trying to authenticate only a single endpoint (/protected), but we need to secure all the endpoints using kerberos authentication. This is the web security config(same code is working with Spring Boot 1.5.13.RELEASE but not with Spring Boot 2.0.3.RELEASE):

package com.findwise.kerberos.config;

import com.findwise.kerberos.localhost.LocalhostAuthFilter;
import com.findwise.kerberos.localhost.LocalhostAuthProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.BeanIds;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.kerberos.authentication.KerberosServiceAuthenticationProvider;
import org.springframework.security.kerberos.authentication.sun.SunJaasKerberosTicketValidator;
import org.springframework.security.kerberos.client.config.SunJaasKrb5LoginConfig;
import org.springframework.security.kerberos.web.authentication.SpnegoAuthenticationProcessingFilter;
import org.springframework.security.kerberos.web.authentication.SpnegoEntryPoint;
import org.springframework.security.ldap.userdetails.LdapUserDetailsService;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

import java.util.Collection;

/**
 * SpringSecurityConfig:
 * <p>
 * This is our main security configuration - It follows very closely the
 * examples provided by Spring.IO - Spring Security Kerberos.
 *
 * @author Peter Gylling - email: peter.jorgensen@findwise.com
 * @link http://docs.spring.io/spring-security-kerberos/docs/current/reference/htmlsingle/
 */
@Configuration
@EnableWebSecurity
public class SpringSecurityConfig extends WebSecurityConfigurerAdapter {

    @Value("${app.service-principal}")
    private String servicePrincipal;

    @Value("${app.keytab-location}")
    private String keytabLocation;

    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {

        httpSecurity
                .exceptionHandling()
                .authenticationEntryPoint(spnegoEntryPoint())
                .and().authorizeRequests().anyRequest().authenticated()
                .and().addFilterBefore( spnegoAuthenticationProcessingFilter(authenticationManagerBean()),
                BasicAuthenticationFilter.class);
    }

    /**
     * This ensures a global configuration for the security of the application.
     *
     * @param auth
     * @param kerbServiceProvider
     */
    @Autowired
    protected void configureGlobal(AuthenticationManagerBuilder auth,
                                   LocalhostAuthProvider localhostAuthProvider,
                                   KerberosServiceAuthenticationProvider kerbServiceProvider) {
        auth
                .authenticationProvider(localhostAuthProvider)
                .authenticationProvider(kerbServiceProvider);
    }

    /**
     * Provide the default Spring Authentication Manager bean.
     * This is used by the SpnegoAuthenticationProcessingFilter as
     * part of the configuration.
     *
     * @return
     * @throws Exception
     * @see SpnegoAuthenticationProcessingFilter
     */
    @Bean(name = BeanIds.AUTHENTICATION_MANAGER)
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }


    /**
     * LocalhostAuthProvider:
     * Provided with the username from the LocalAuthFilter the LocalhostAuthProvider
     * calls Ldap and extracts the roles of the current user.
     *
     * @return a configured localhost auth provider
     */
    @Bean
    public LocalhostAuthProvider localhostAuthProvider() {
        LocalhostAuthProvider localhostAuthProvider = new LocalhostAuthProvider();
        localhostAuthProvider.setUserDetailsService(new KerberosUserDetailsService());
        return localhostAuthProvider;
    }

    /**
     * LocalhostAuthFilter:
     * Graps the SPNEGO request before the Kerberos based SPNEGO authentication filter
     * and shortcuts the system to allow for local users. (The developer use cae).
     *
     * @param authenticationManager - Standard Spring Security
     * @return a configured LocalHostAuth filter.
     */
    @Bean
    public LocalhostAuthFilter localhostAuthFilter(AuthenticationManager authenticationManager) {
        LocalhostAuthFilter localhostAuthFilter = new LocalhostAuthFilter();
        localhostAuthFilter.setAuthenticationManager(authenticationManager);
        return localhostAuthFilter;
    }


    /**
     * Setup SpnegoEntryPoint to point to the login
     * page provided by the login.jsp page.
     *
     * @return
     */
    @Bean
    public SpnegoEntryPoint spnegoEntryPoint() {
        return new SpnegoEntryPoint("/protected");
    }

    /**
     * SpnegoAuthenticationProcessingFilter:
     * <p>
     * This is your friendly SSO filter, that kindly automatically
     * logs the user in if the Browser provides the actual credentials
     *
     * @param authenticationManager - with BeanIds.AUTHENTICATION_MANAGER
     * @return
     * @See AuthenticationManager
     */
    @Bean
    public SpnegoAuthenticationProcessingFilter spnegoAuthenticationProcessingFilter(
            AuthenticationManager authenticationManager) {
        SpnegoAuthenticationProcessingFilter filter = new SpnegoAuthenticationProcessingFilter();
        filter.setAuthenticationManager(authenticationManager);
        return filter;
    }

    /**
     * KerberosServiceAuthenticationProvider:
     * <p>
     * This bean is needed by the global AuthenticationManager bean as the only
     * accepted authentication providers.
     * <p>
     * To actually provide Spring Security with the required user details the
     * LdapUserDetailsService is provided to the service auth provider.
     * <p>
     * The Ldap service will not be used until the TicketValidator has granted
     * general access.
     *
     * @return - A configured Kerberos Service Auth Provider
     * @see SunJaasKerberosTicketValidator
     * @see LdapUserDetailsService
     */
    @Bean
    public KerberosServiceAuthenticationProvider kerberosServiceAuthenticationProvider() {
        KerberosServiceAuthenticationProvider provider = new KerberosServiceAuthenticationProvider();
        provider.setTicketValidator(sunJaasKerberosTicketValidator());
        provider.setUserDetailsService(new KerberosUserDetailsService());
        return provider;
    }

    /**
     * SunJaasKerberosTicketValidator
     * <p>
     * This bean will on behalf of the web application validate the visiting users provided
     * Kerberos Ticket. This will not kick in if the underlying JAAS and KRB5 configuration is
     * not working as expected.
     * <p>
     * Find the values of the servicePrincipal and keytabLocation in application.properties
     *
     * @return - A Kerberos Ticket Validator
     * @see KerberosGlobalConfig
     */
    @Bean
    public SunJaasKerberosTicketValidator sunJaasKerberosTicketValidator() {
        SunJaasKerberosTicketValidator ticketValidator = new SunJaasKerberosTicketValidator();
        ticketValidator.setServicePrincipal(servicePrincipal);
        ticketValidator.setKeyTabLocation(new FileSystemResource(keytabLocation));
        ticketValidator.setDebug(true);

        return ticketValidator;
    }


    /**
     * SunJaasKrb5LoginConfig
     * <p>
     * This is what you would previously find in a JAAS Conf file.
     * <p>
     * Find the servicePrincipal and keytabLocation is application.properties
     *
     * @return a configured JAAS login
     * @see SunJaasKrb5LoginConfig
     */
    @Bean
    public SunJaasKrb5LoginConfig loginConfig() {
        SunJaasKrb5LoginConfig loginConfig = new SunJaasKrb5LoginConfig();
        loginConfig.setKeyTabLocation(new FileSystemResource(keytabLocation));
        loginConfig.setServicePrincipal(servicePrincipal);
        loginConfig.setDebug(true);
        loginConfig.setIsInitiator(true);
        loginConfig.setUseTicketCache(true);
        return loginConfig;
    }


    protected static class KerberosUserDetailsService implements UserDetailsService {

        @Override
        public UserDetails loadUserByUsername(final String s) throws UsernameNotFoundException {
            return new UserDetails() {
                @Override
                public Collection<? extends GrantedAuthority> getAuthorities() {
                    return null;
                }

                @Override
                public String getPassword() {
                    return null;
                }

                @Override
                public String getUsername() {
                    return s;
                }

                @Override
                public boolean isAccountNonExpired() {
                    return true;
                }

                @Override
                public boolean isAccountNonLocked() {
                    return true;
                }

                @Override
                public boolean isCredentialsNonExpired() {
                    return true;
                }

                @Override
                public boolean isEnabled() {
                    return true;
                }
            };
        }
    }
}

Answer 1

Kerberos service principal didn't setup properly. Now its working fine.

Basic configuration steps :

1) Krb5 conf should be loaded properly (it contains KDC and realm related information).

2) Service principal (HTTP/xyz) must be created and keytab should be provided as a configuration.

3) If you are calling any rest service via client program then you need to provide user principal and keytab, or you can use local Kerberos cache (krb5_123x).