Add OIDC TokenCertificateValidator

docs/src/main/asciidoc/security-oidc-bearer-token-authentication.adoc

@@ -470,6 +470,66 @@ quarkus.oidc.introspection-path=/protocol/openid-connect/tokens/introspect
 
 For information about bearer access token propagation to the downstream services, see the xref:security-openid-connect-client-reference.adoc#token-propagation[Token propagation] section of the Quarkus "OpenID Connect (OIDC) and OAuth2 client and filters reference" guide.
 
+=== JWT token certificate chain
+
+In some cases, JWT bearer tokens have an `x5c` header which represents an X509 certificate chain whose leaf certificate contains a public key that must be used to verify this token's signature.
+Before this public key can be accepted to verify the signature, the certificate chain must be validated first.
+The certificate chain validation involves several steps:
+
+1. Confirm that every certificate but the root one is signed by the parent certificate.
+
+2. Confirm the chain's root certificate is also imported in the truststore.
+
+3. Validate the chain's leaf certificate. If a common name of the leaf certificate is configured then a common name of the chain's leaf certificate must match it. Otherwise the chain's leaf certificate must also be avaiable in the truststore, unless one or more custom `TokenCertificateValidator` implementations are registered.
+
+4. `quarkus.oidc.TokenCertificateValidator` can be used to add a custom certificate chain validation step. It can be used by all tenants expecting tokens with the certificate chain or bound to specific OIDC tenants with the `@quarkus.oidc.TenantFeature` annotation.
+
+For example, here is how you can configure Quarkus OIDC to verify the token's certificate chain, without using `quarkus.oidc.TokenCertificateValidator`:
+
+[source,properties]
+----
+quarkus.oidc.certificate-chain.trust-store-file=truststore-rootcert.p12 <1>
+quarkus.oidc.certificate-chain.trust-store-password=storepassword
+quarkus.oidc.certificate-chain.leaf-certificate-name=www.quarkusio.com <2>
+----
+<1> The truststore must contain the certificate chain's root certificate.
+<2> The certificate chain's leaf certificate must have a common name equal to `www.quarkusio.com`. If this property is not configured then the truststore must contain the certificate chain's leaf certificate unless one or more custom `TokenCertificateValidator` implementations are registered.
+
+You can add a custom certificate chain validation step by registering a custom `quarkus.oidc.TokenCertificateValidator`, for example:
+
+[source,java]
+----
+package io.quarkus.it.keycloak;
+
+import java.security.cert.CertificateException;
+import java.security.cert.X509Certificate;
+import java.util.List;
+
+import jakarta.enterprise.context.ApplicationScoped;
+
+import io.quarkus.arc.Unremovable;
+import io.quarkus.oidc.OidcTenantConfig;
+import io.quarkus.oidc.TokenCertificateValidator;
+import io.quarkus.oidc.runtime.TrustStoreUtils;
+import io.vertx.core.json.JsonObject;
+
+@ApplicationScoped
+@Unremovable
+public class BearerGlobalTokenChainValidator implements TokenCertificateValidator {
+
+    @Override
+    public void validate(OidcTenantConfig oidcConfig, List<X509Certificate> chain, String tokenClaims) throws CertificateException {
+        String rootCertificateThumbprint = TrustStoreUtils.calculateThumprint(chain.get(chain.size() - 1));
+        JsonObject claims = new JsonObject(tokenClaims);
+        if (!rootCertificateThumbprint.equals(claims.getString("root-certificate-thumbprint"))) { <1>
+            throw new CertificateException("Invalid root certificate");
+        }
+    }
+}
+
+----
+<1> Confirm that the certificate chain's root certificate is bound to the custom JWT token's claim.
+
 === OIDC provider client authentication
 
 `quarkus.oidc.runtime.OidcProviderClient` is used when a remote request to an OIDC provider is required.

extensions/oidc/runtime/src/main/java/io/quarkus/oidc/TokenCertificateValidator.java

@@ -0,0 +1,25 @@
+package io.quarkus.oidc;
+
+import java.security.cert.CertificateException;
+import java.security.cert.X509Certificate;
+import java.util.List;
+
+/**
+ * TokenCertificateValidator can be used to verify X509 certificate chain
+ * that is inlined in the JWT token as a 'x5c' header value.
+ *
+ * Use {@link TenantFeature} qualifier to bind this validator to specific OIDC tenants.
+ */
+public interface TokenCertificateValidator {
+    /**
+     * Validate X509 certificate chain
+     *
+     * @param oidcConfig current OIDC tenant configuration.
+     * @param chain the certificate chain. The first element in the list is a leaf certificate, the last element - the root
+     *        certificate.
+     * @param tokenClaims the decoded JWT token claims in JSON format. If necessary, implementations can convert it to JSON
+     *        object.
+     * @throws {@link CertificateException} if the certificate chain validation has failed.
+     */
+    void validate(OidcTenantConfig oidcConfig, List<X509Certificate> chain, String tokenClaims) throws CertificateException;
+}

extensions/oidc/runtime/src/main/java/io/quarkus/oidc/runtime/CertChainPublicKeyResolver.java

@@ -11,24 +11,32 @@
 import org.jose4j.jwx.JsonWebStructure;
 import org.jose4j.lang.UnresolvableKeyException;
 
-import io.quarkus.oidc.OidcTenantConfig.CertificateChain;
+import io.quarkus.oidc.OidcTenantConfig;
+import io.quarkus.oidc.TokenCertificateValidator;
 import io.quarkus.runtime.configuration.ConfigurationException;
 import io.quarkus.security.runtime.X509IdentityProvider;
 import io.vertx.ext.auth.impl.CertificateHelper;
 
 public class CertChainPublicKeyResolver implements RefreshableVerificationKeyResolver {
     private static final Logger LOG = Logger.getLogger(OidcProvider.class);
+    final OidcTenantConfig oidcConfig;
     final Set<String> thumbprints;
     final Optional<String> expectedLeafCertificateName;
+    final List<TokenCertificateValidator> certificateValidators;
 
-    public CertChainPublicKeyResolver(CertificateChain chain) {
-        if (chain.getTrustStorePassword().isEmpty()) {
+    public CertChainPublicKeyResolver(OidcTenantConfig oidcConfig) {
+        this.oidcConfig = oidcConfig;
+        if (oidcConfig.certificateChain.getTrustStorePassword().isEmpty()) {
             throw new ConfigurationException(
                     "Truststore with configured password which keeps thumbprints of the trusted certificates must be present");
         }
-        this.thumbprints = TrustStoreUtils.getTrustedCertificateThumbprints(chain.trustStoreFile.get(),
-                chain.getTrustStorePassword().get(), chain.trustStoreCertAlias, chain.getTrustStoreFileType());
-        this.expectedLeafCertificateName = chain.leafCertificateName;
+        this.thumbprints = TrustStoreUtils.getTrustedCertificateThumbprints(
+                oidcConfig.certificateChain.trustStoreFile.get(),
+                oidcConfig.certificateChain.getTrustStorePassword().get(),
+                oidcConfig.certificateChain.trustStoreCertAlias,
+                oidcConfig.certificateChain.getTrustStoreFileType());
+        this.expectedLeafCertificateName = oidcConfig.certificateChain.leafCertificateName;
+        this.certificateValidators = TenantFeatureFinder.find(oidcConfig, TokenCertificateValidator.class);
     }
 
     @Override
@@ -45,34 +53,52 @@ public Key resolveKey(JsonWebSignature jws, List<JsonWebStructure> nestingContex
                 LOG.debug("Token 'x5c' certificate chain is empty");
                 return null;
             }
+
+            // General certificate chain validation
+            //TODO: support revocation lists
+            CertificateHelper.checkValidity(chain, null);
+            if (chain.size() == 1) {
+                // CertificateHelper.checkValidity does not currently
+                // verify the certificate signature if it is a single certificate chain
+                final X509Certificate root = chain.get(0);
+                root.verify(root.getPublicKey());
+            }
+
+            // Always do the root certificate thumbprint check
             LOG.debug("Checking a thumbprint of the root chain certificate");
             String rootThumbprint = TrustStoreUtils.calculateThumprint(chain.get(chain.size() - 1));
             if (!thumbprints.contains(rootThumbprint)) {
                 LOG.error("Thumprint of the root chain certificate is invalid");
                 throw new UnresolvableKeyException("Thumprint of the root chain certificate is invalid");
             }
-            if (expectedLeafCertificateName.isEmpty()) {
-                LOG.debug("Checking a thumbprint of the leaf chain certificate");
-                String thumbprint = TrustStoreUtils.calculateThumprint(chain.get(0));
-                if (!thumbprints.contains(thumbprint)) {
-                    LOG.error("Thumprint of the leaf chain certificate is invalid");
-                    throw new UnresolvableKeyException("Thumprint of the leaf chain certificate is invalid");
+
+            // Run custom validators if any
+            if (!certificateValidators.isEmpty()) {
+                LOG.debug("Running custom TokenCertificateValidators");
+                for (TokenCertificateValidator validator : certificateValidators) {
+                    validator.validate(oidcConfig, chain, jws.getUnverifiedPayload());
                 }
-            } else {
+            }
+
+            // Finally, check the leaf certificate if required
+            if (!expectedLeafCertificateName.isEmpty()) {
+                // Compare the leaf certificate common name against the configured value
                 String leafCertificateName = X509IdentityProvider.getCommonName(chain.get(0).getSubjectX500Principal());
                 if (!expectedLeafCertificateName.get().equals(leafCertificateName)) {
                     LOG.errorf("Wrong leaf certificate common name: %s", leafCertificateName);
                     throw new UnresolvableKeyException("Wrong leaf certificate common name");
                 }
+            } else if (certificateValidators.isEmpty()) {
+                // No custom validators are registered and no leaf certificate CN is configured
+                // Check that the truststore contains a leaf certificate thumbprint
+                LOG.debug("Checking a thumbprint of the leaf chain certificate");
+                String thumbprint = TrustStoreUtils.calculateThumprint(chain.get(0));
+                if (!thumbprints.contains(thumbprint)) {
+                    LOG.error("Thumprint of the leaf chain certificate is invalid");
+                    throw new UnresolvableKeyException("Thumprint of the leaf chain certificate is invalid");
+                }
             }
-            //TODO: support revocation lists
-            CertificateHelper.checkValidity(chain, null);
-            if (chain.size() == 1) {
-                // CertificateHelper.checkValidity does not currently
-                // verify the certificate signature if it is a single certificate chain
-                final X509Certificate root = chain.get(0);
-                root.verify(root.getPublicKey());
-            }
+
             return chain.get(0).getPublicKey();
         } catch (UnresolvableKeyException ex) {
             throw ex;

extensions/oidc/runtime/src/main/java/io/quarkus/oidc/runtime/DynamicVerificationKeyResolver.java

@@ -39,7 +39,7 @@ public DynamicVerificationKeyResolver(OidcProviderClient client, OidcTenantConfi
         this.cache = new MemoryCache<Key>(client.getVertx(), config.jwks.cleanUpTimerInterval,
                 config.jwks.cacheTimeToLive, config.jwks.cacheSize);
         if (config.certificateChain.trustStoreFile.isPresent()) {
-            chainResolverFallback = new CertChainPublicKeyResolver(config.certificateChain);
+            chainResolverFallback = new CertChainPublicKeyResolver(config);
         } else {
             chainResolverFallback = null;
         }

extensions/oidc/runtime/src/main/java/io/quarkus/oidc/runtime/OidcProvider.java

@@ -4,14 +4,12 @@
 import java.nio.charset.StandardCharsets;
 import java.security.Key;
 import java.time.Duration;
-import java.util.ArrayList;
 import java.util.Base64;
 import java.util.List;
 import java.util.Map;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-import jakarta.enterprise.inject.Default;
 import jakarta.json.JsonObject;
 
 import org.eclipse.microprofile.jwt.Claims;
@@ -32,14 +30,11 @@
 import org.jose4j.lang.InvalidAlgorithmException;
 import org.jose4j.lang.UnresolvableKeyException;
 
-import io.quarkus.arc.Arc;
 import io.quarkus.logging.Log;
 import io.quarkus.oidc.AuthorizationCodeTokens;
 import io.quarkus.oidc.OIDCException;
 import io.quarkus.oidc.OidcConfigurationMetadata;
 import io.quarkus.oidc.OidcTenantConfig;
-import io.quarkus.oidc.OidcTenantConfig.CertificateChain;
-import io.quarkus.oidc.TenantFeature.TenantFeatureLiteral;
 import io.quarkus.oidc.TokenCustomizer;
 import io.quarkus.oidc.TokenIntrospection;
 import io.quarkus.oidc.UserInfo;
@@ -84,8 +79,8 @@ public class OidcProvider implements Closeable {
     final AlgorithmConstraints requiredAlgorithmConstraints;
 
     public OidcProvider(OidcProviderClient client, OidcTenantConfig oidcConfig, JsonWebKeySet jwks, Key tokenDecryptionKey) {
-        this(client, oidcConfig, jwks, TokenCustomizerFinder.find(oidcConfig), tokenDecryptionKey,
-                getCustomValidators(oidcConfig));
+        this(client, oidcConfig, jwks, TenantFeatureFinder.find(oidcConfig), tokenDecryptionKey,
+                TenantFeatureFinder.find(oidcConfig, Validator.class));
     }
 
     public OidcProvider(OidcProviderClient client, OidcTenantConfig oidcConfig, JsonWebKeySet jwks,
@@ -94,10 +89,9 @@ public OidcProvider(OidcProviderClient client, OidcTenantConfig oidcConfig, Json
         this.oidcConfig = oidcConfig;
         this.tokenCustomizer = tokenCustomizer;
         if (jwks != null) {
-            this.asymmetricKeyResolver = new JsonWebKeyResolver(jwks, oidcConfig.token.forcedJwkRefreshInterval,
-                    oidcConfig.certificateChain);
+            this.asymmetricKeyResolver = new JsonWebKeyResolver(jwks, oidcConfig.token.forcedJwkRefreshInterval);
         } else if (oidcConfig != null && oidcConfig.certificateChain.trustStoreFile.isPresent()) {
-            this.asymmetricKeyResolver = new CertChainPublicKeyResolver(oidcConfig.certificateChain);
+            this.asymmetricKeyResolver = new CertChainPublicKeyResolver(oidcConfig);
         } else {
             this.asymmetricKeyResolver = null;
         }
@@ -112,22 +106,17 @@ public OidcProvider(OidcProviderClient client, OidcTenantConfig oidcConfig, Json
         this.requiredClaims = checkRequiredClaimsProp();
         this.tokenDecryptionKey = tokenDecryptionKey;
         this.requiredAlgorithmConstraints = checkSignatureAlgorithm();
-
-        if (customValidators != null && !customValidators.isEmpty()) {
-            this.customValidators = customValidators;
-        } else {
-            this.customValidators = null;
-        }
+        this.customValidators = customValidators == null ? List.of() : customValidators;
     }
 
     public OidcProvider(String publicKeyEnc, OidcTenantConfig oidcConfig, Key tokenDecryptionKey) {
         this.client = null;
         this.oidcConfig = oidcConfig;
-        this.tokenCustomizer = TokenCustomizerFinder.find(oidcConfig);
+        this.tokenCustomizer = TenantFeatureFinder.find(oidcConfig);
         if (publicKeyEnc != null) {
             this.asymmetricKeyResolver = new LocalPublicKeyResolver(publicKeyEnc);
         } else if (oidcConfig.certificateChain.trustStoreFile.isPresent()) {
-            this.asymmetricKeyResolver = new CertChainPublicKeyResolver(oidcConfig.certificateChain);
+            this.asymmetricKeyResolver = new CertChainPublicKeyResolver(oidcConfig);
         } else {
             throw new IllegalStateException("Neither public key nor certificate chain verification modes are enabled");
         }
@@ -137,7 +126,7 @@ public OidcProvider(String publicKeyEnc, OidcTenantConfig oidcConfig, Key tokenD
         this.requiredClaims = checkRequiredClaimsProp();
         this.tokenDecryptionKey = tokenDecryptionKey;
         this.requiredAlgorithmConstraints = checkSignatureAlgorithm();
-        this.customValidators = getCustomValidators(oidcConfig);
+        this.customValidators = TenantFeatureFinder.find(oidcConfig, Validator.class);
     }
 
     private AlgorithmConstraints checkSignatureAlgorithm() {
@@ -223,10 +212,8 @@ private TokenVerificationResult verifyJwtTokenInternal(String token,
             builder.registerValidator(new CustomClaimsValidator(Map.of(OidcConstants.NONCE, nonce)));
         }
 
-        if (customValidators != null) {
-            for (Validator customValidator : customValidators) {
-                builder.registerValidator(customValidator);
-            }
+        for (Validator customValidator : customValidators) {
+            builder.registerValidator(customValidator);
         }
 
         if (issuedAtRequired) {
@@ -438,11 +425,11 @@ private class JsonWebKeyResolver implements RefreshableVerificationKeyResolver {
         volatile long forcedJwksRefreshIntervalMilliSecs;
         final CertChainPublicKeyResolver chainResolverFallback;
 
-        JsonWebKeyResolver(JsonWebKeySet jwks, Duration forcedJwksRefreshInterval, CertificateChain chain) {
+        JsonWebKeyResolver(JsonWebKeySet jwks, Duration forcedJwksRefreshInterval) {
             this.jwks = jwks;
             this.forcedJwksRefreshIntervalMilliSecs = forcedJwksRefreshInterval.toMillis();
-            if (chain.trustStoreFile.isPresent()) {
-                chainResolverFallback = new CertChainPublicKeyResolver(chain);
+            if (oidcConfig.certificateChain.trustStoreFile.isPresent()) {
+                chainResolverFallback = new CertChainPublicKeyResolver(oidcConfig);
             } else {
                 chainResolverFallback = null;
             }
@@ -618,24 +605,4 @@ public String validate(JwtContext jwtContext) throws MalformedClaimException {
         }
     }
 
-    private static List<Validator> getCustomValidators(OidcTenantConfig oidcTenantConfig) {
-        if (oidcTenantConfig != null && oidcTenantConfig.tenantId.isPresent()) {
-            var tenantsValidators = new ArrayList<Validator>();
-            for (var instance : Arc.container().listAll(Validator.class, Default.Literal.INSTANCE)) {
-                if (instance.isAvailable()) {
-                    tenantsValidators.add(instance.get());
-                }
-            }
-            for (var instance : Arc.container().listAll(Validator.class,
-                    TenantFeatureLiteral.of(oidcTenantConfig.tenantId.get()))) {
-                if (instance.isAvailable()) {
-                    tenantsValidators.add(instance.get());
-                }
-            }
-            if (!tenantsValidators.isEmpty()) {
-                return List.copyOf(tenantsValidators);
-            }
-        }
-        return null;
-    }
 }