Support OIDC signed UserInfo with charset content type parameters

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

@@ -415,7 +415,7 @@ public Uni<UserInfo> getUserInfo(String accessToken) {
 
                     @Override
                     public Uni<UserInfo> apply(UserInfoResponse response) {
-                        if (APPLICATION_JWT_CONTENT_TYPE.equals(response.contentType())) {
+                        if (isApplicationJwtContentType(response.contentType())) {
                             if (oidcConfig.jwks.resolveEarly) {
                                 try {
                                     LOG.debugf("Verifying the signed UserInfo with the local JWK keys: %s", response.data());
@@ -446,6 +446,21 @@ public Uni<UserInfo> apply(UserInfoResponse response) {
                 });
     }
 
+    static boolean isApplicationJwtContentType(String ct) {
+        if (ct == null) {
+            return false;
+        }
+        ct = ct.trim();
+        if (!ct.startsWith(APPLICATION_JWT_CONTENT_TYPE)) {
+            return false;
+        }
+        if (ct.length() == APPLICATION_JWT_CONTENT_TYPE.length()) {
+            return true;
+        }
+        String remainder = ct.substring(APPLICATION_JWT_CONTENT_TYPE.length()).trim();
+        return remainder.indexOf(';') == 0;
+    }
+
     public Uni<AuthorizationCodeTokens> getCodeFlowTokens(String code, String redirectUri, String codeVerifier) {
         return client.getAuthorizationCodeTokens(code, redirectUri, codeVerifier);
     }

extensions/oidc/runtime/src/test/java/io/quarkus/oidc/runtime/OidcProviderTest.java

@@ -1,6 +1,7 @@
 package io.quarkus.oidc.runtime;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
@@ -310,4 +311,15 @@ public String validate(JwtContext jwtContext) throws MalformedClaimException {
             }
         }
     }
+
+    @Test
+    public void testJwtContentTypeCheck() {
+        assertTrue(OidcProvider.isApplicationJwtContentType("application/jwt"));
+        assertTrue(OidcProvider.isApplicationJwtContentType(" application/jwt "));
+        assertTrue(OidcProvider.isApplicationJwtContentType("application/jwt;charset=UTF-8"));
+        assertTrue(OidcProvider.isApplicationJwtContentType(" application/jwt ; charset=UTF-8"));
+        assertFalse(OidcProvider.isApplicationJwtContentType(" application/jwt-custom"));
+        assertFalse(OidcProvider.isApplicationJwtContentType(" application/json"));
+        assertFalse(OidcProvider.isApplicationJwtContentType(null));
+    }
 }

integration-tests/oidc-wiremock/src/test/java/io/quarkus/it/keycloak/CodeFlowAuthorizationTest.java

@@ -617,7 +617,7 @@ private void defineCodeFlowUserInfoCachedInIdTokenStub() {
                 get(urlEqualTo("/auth/realms/quarkus/protocol/openid-connect/signeduserinfo"))
                         .withHeader("Authorization", containing("Bearer ey"))
                         .willReturn(aResponse()
-                                .withHeader("Content-Type", "application/jwt")
+                                .withHeader("Content-Type", " application/jwt ; charset=UTF-8")
                                 .withBody(
                                         Jwt.preferredUserName("alice")
                                                 .issuer("https://server.example.com")