Spring security introspection not working - spring-boot

Question

I'm trying to implement opaque token validation for my resource server, which runs on Spring Boot 2.4.5 with the dependencies spring-boot-starter-oauth2-resource-server and oauth2-oidc-sdk, and I am struggling to make the call to the introspection endpoint work.
The authorization server is WSO2 Identity Server.
Here's my code:
#Configuration
#EnableWebSecurity
public class OAuth2ResourceServerConfiguration extends WebSecurityConfigurerAdapter {
#Value("${spring.security.oauth2.resourceserver.opaquetoken.introspection-uri}")
String introspectionUri;
#Value("${spring.security.oauth2.resourceserver.opaquetoken.client-id}")
String clientId;
#Value("${spring.security.oauth2.resourceserver.opaquetoken.client-secret}")
String clientSecret;
#Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests(authorize -> authorize
.anyRequest().authenticated()
)
.oauth2ResourceServer(oauth2 -> oauth2
.opaqueToken(opaque -> opaque
.introspectionUri(this.introspectionUri)
.introspectionClientCredentials(this.clientId, this.clientSecret)
)
);
}
}
In the application.properties I've got:
spring.security.oauth2.resourceserver.opaquetoken.introspection-uri=https://localhost:9443/oauth2/introspect
spring.security.oauth2.resourceserver.opaquetoken.client-id=admin
spring.security.oauth2.resourceserver.opaquetoken.client-secret=admin
The backend replies to all requests with 401, and it doesn't seem to even contact the authorization server. I read the documentation and watched plenty of examples, but can't figure out what's wrong. Could you help me please?
I also would like to know if the use of the introspection endpoint is correct and if it's the only way a resource server has to validate a non-JWT token.
Edit: #jzheaux: I was using DEBUG logging, now with TRACE I get this exception:
org.springframework.security.authentication.AuthenticationServiceException: I/O error on POST request for "https://localhost:9443/oauth2/introspect": PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target; nested exception is javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at org.springframework.security.oauth2.server.resource.authentication.OpaqueTokenAuthenticationProvider.getOAuth2AuthenticatedPrincipal(OpaqueTokenAuthenticationProvider.java:110)
at org.springframework.security.oauth2.server.resource.authentication.OpaqueTokenAuthenticationProvider.authenticate(OpaqueTokenAuthenticationProvider.java:94)
at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:182)
at org.springframework.security.oauth2.server.resource.web.BearerTokenAuthenticationFilter.doFilterInternal(BearerTokenAuthenticationFilter.java:122)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:103)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:89)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:117)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:110)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:336)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:211)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:183)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834)
It seems like a certification problem, but with Postman WSO2's introspection endpoint works flawlessly.
These are the response headers as shown by Postman (body is empty):

Answer 1

The problem is with the WSO2 Identity Server's certificate. You need to import the it into java's cacerts file (inside lib/security).