Failed to select a JWK signing key - Trying to implement Elliptic Curve keys to sign OAuth2AuthorizationServer's JWKS

Question

I'm trying to use the new spring security's oauth2-authorization-server using authorization code grant flow in my project while following the samples provided in it's github repo but decided to set ES256 instead of RS256 .

In the following its presented my AuthzServerConfig.class exposing the JWKSource :

@Import( OAuth2AuthorizationServerConfiguration.class )
@Configuration( proxyBeanMethods = false )
public class AuthzServerConfig { 

    // ommited code above


        @Bean
        public JWKSource<SecurityContext> jwkSource() throws 
          NoSuchAlgorithmException, InvalidAlgorithmParameterException, JOSEException {

            JWKSet keySet = new JWKSet( KeyGenerator.getEcJwk() ); // <- here i call the desired keypair

            return ( jwkSelector, context ) -> jwkSelector.select( keySet ); 
        }


   // ommited code bellow
}

Next my KeyGenerator.class responsable for generate the keys:

public class KeyGenerator {


    public static ECKey getECKeys(){

        var ops = setKeyOperations( KeyOperation.SIGN, KeyOperation.VERIFY );
    
        try{
            return new ECKeyGenerator( Curve.P_256 )
                        .keyID( UUID.randomUUID().toString() )
                        .keyUse( KeyUse.SIGNATURE )
                        .algorithm( 
                            new Algorithm( 
                                SignatureAlgorithm.ES256.toString(), 
                                Requirement.RECOMMENDED ) 
                        )
                        .keyOperations( ops )
                        .generate();
        }
        catch( Exception ex ){
            throw new IllegalStateException();
        }
    }

    public static RSAKey getRsaKeys() throws JOSEException {

        var operations = setKeyOperations( KeyOperation.SIGN, KeyOperation.VERIFY );

        return new RSAKeyGenerator( 2048 )
                        .keyID( UUID.randomUUID().toString() )
                        .keyUse( KeyUse.SIGNATURE )
                        .algorithm( 
                            new Algorithm( 
                                SignatureAlgorithm.RS256.toString(), 
                                Requirement.RECOMMENDED ) 
                        )
                        .keyOperations( operations )
                        .generate();
    }

    public static Set<KeyOperation> setKeyOperations( KeyOperation... operations ) {

        var operationsSet = new HashSet<KeyOperation>();
        var proceed = Collections.addAll( operationsSet, operations);

        var message = "Sign-keys generation could not set its operations.";
        message.concat( "Check KeyGenerator::setKeyOperations" );

        Assert.isTrue( proceed, message );

        return operationsSet;
    }

    public static JWK getEcJwk() throws 
      NoSuchAlgorithmException, InvalidAlgorithmParameterException {

        KeyPairGenerator gen = KeyPairGenerator.getInstance( "EC" );
        gen.initialize( Curve.P_256.toECParameterSpec() );
        KeyPair pair = gen.generateKeyPair();
    
        return new ECKey.Builder( Curve.P_256 , ( ECPublicKey ) pair.getPublic() )
                    .privateKey( ( ECPrivateKey ) pair.getPrivate() )
                    .build();
    }

    public static JWK getRsaJwk() throws 
      NoSuchAlgorithmException, InvalidAlgorithmParameterException {

        KeyPairGenerator gen = KeyPairGenerator.getInstance( "RSA" );
        gen.initialize( 2048 );
        KeyPair pair = gen.generateKeyPair();
    
        return new RSAKey.Builder( ( RSAPublicKey ) pair.getPublic() )
                    .privateKey( ( RSAPrivateKey ) pair.getPrivate() )
                    .keyID( UUID.randomUUID().toString() )
                    .keyUse( KeyUse.SIGNATURE )
                    .build();
    }
}

As can be seen above i provided 4 different methods two for each Signature algorithm and only those that implement RS256 worked perfectly fine while those with ES256 threw me the following stack trace:

org.springframework.security.oauth2.jwt.JwtEncodingException: An error occurred while attempting to encode the Jwt: Failed to select a JWK signing key
    at org.springframework.security.oauth2.jwt.NimbusJwsEncoder.selectJwk(NimbusJwsEncoder.java:120) ~[spring-security-oauth2-authorization-server-0.2.2.jar:5.6.1]
    at org.springframework.security.oauth2.jwt.NimbusJwsEncoder.encode(NimbusJwsEncoder.java:96) ~[spring-security-oauth2-authorization-server-0.2.2.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.authentication.OAuth2AuthorizationCodeAuthenticationProvider.authenticate(OAuth2AuthorizationCodeAuthenticationProvider.java:193) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:182) ~[spring-security-core-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.OAuth2TokenEndpointFilter.doFilterInternal(OAuth2TokenEndpointFilter.java:165) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:115) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:81) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:122) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:116) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:126) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:81) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:109) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:149) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.OAuth2ClientAuthenticationFilter.doFilterInternal(OAuth2ClientAuthenticationFilter.java:115) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.OAuth2AuthorizationServerMetadataEndpointFilter.doFilterInternal(OAuth2AuthorizationServerMetadataEndpointFilter.java:77) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.NimbusJwkSetEndpointFilter.doFilterInternal(NimbusJwkSetEndpointFilter.java:85) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.oidc.web.OidcProviderConfigurationEndpointFilter.doFilterInternal(OidcProviderConfigurationEndpointFilter.java:79) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.OAuth2AuthorizationEndpointFilter.doFilterInternal(OAuth2AuthorizationEndpointFilter.java:140) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:117) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.oauth2.server.authorization.web.ProviderContextFilter.doFilterInternal(ProviderContextFilter.java:63) ~[spring-security-oauth2-authorization-server-0.2.2.jar:0.2.2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:110) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:211) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.debug.DebugFilter.invokeWithWrappedRequest(DebugFilter.java:90) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.debug.DebugFilter.doFilter(DebugFilter.java:78) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.security.web.debug.DebugFilter.doFilter(DebugFilter.java:67) ~[spring-security-web-5.6.1.jar:5.6.1]
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:354) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1732) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

Inspecting this i ended up at line 172 of OAuth2AuthorizationCodeAuthenticationProvider spring security class:

JoseHeader.Builder headersBuilder = JwtUtils.headers();

Which builds a JwtEncodingContext's header with RS256 set as signature algorithm which is suspicious for not let me use ES256 , in my point of view.

I'm a newbie at this and can be totally wrong and away from the real problem. Can you guys figure out what i might be doing wrong??

Thanks in advance

Answer 1

Thanks to @Steve Riesenberg 's comment pointing me to this link in github , i could get i done and the resulting solution in my AuthzServerConfig.class looks as it follows:

@Import( OAuth2AuthorizationServerConfiguration.class )
@Configuration( proxyBeanMethods = false )
public class AuthzServerConfig { 

    ...

        @Bean
        public JWKSource<SecurityContext> jwkSource() throws 
          NoSuchAlgorithmException, InvalidAlgorithmParameterException, JOSEException {

            JWKSet keySet = new JWKSet( KeyGenerator.getEcJwk() ); // <- KeyGenerator is an external code

            return ( jwkSelector, context ) -> jwkSelector.select( keySet ); 
        }

        // start of the solution
        @Bean
        public OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer() {
            return context -> context.getHeaders().algorithm( SignatureAlgorithm.ES256 );
        }
        // end of the solution

   ...
}

Putting into words i just needed to expose an OAuth2TokenCustomizer implementation which sets JwtEncodingContext's header with ES256 signature algorithm.