Add timeout parameter to critical remote http call in mutex section

Author: Fridolin Jackstadt

oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwtDecoder.java

@@ -42,6 +42,7 @@
 import com.nimbusds.jose.jwk.source.JWKSetSource;
 import com.nimbusds.jose.jwk.source.JWKSource;
 import com.nimbusds.jose.jwk.source.JWKSourceBuilder;
+import com.nimbusds.jose.jwk.source.RemoteJWKSet;
 import com.nimbusds.jose.proc.DefaultJOSEObjectTypeVerifier;
 import com.nimbusds.jose.proc.JOSEObjectTypeVerifier;
 import com.nimbusds.jose.proc.JWSKeySelector;
@@ -66,6 +67,7 @@
 import org.springframework.http.MediaType;
 import org.springframework.http.RequestEntity;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.SimpleClientHttpRequestFactory;
 import org.springframework.security.oauth2.core.OAuth2Error;
 import org.springframework.security.oauth2.core.OAuth2TokenValidator;
 import org.springframework.security.oauth2.core.OAuth2TokenValidatorResult;
@@ -293,7 +295,7 @@ public static final class JwkSetUriJwtDecoderBuilder {
 
 		private final Set<SignatureAlgorithm> signatureAlgorithms = new HashSet<>();
 
-		private RestOperations restOperations = new RestTemplate();
+		private RestOperations restOperations = new RestTemplateWithTimeouts();
 
 		private Cache cache = new NoOpCache("default");
 
@@ -545,6 +547,21 @@ public void close() {
 
 	}
 
+	/**
+	 * A RestTemplate with timeouts configured to avoid blocking indefinitely when
+	 * fetching JWK Sets while holding the reentrantLock.
+	 */
+	private static final class  RestTemplateWithTimeouts extends RestTemplate {
+
+		private RestTemplateWithTimeouts () {
+			SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
+			requestFactory.setConnectTimeout(RemoteJWKSet.DEFAULT_HTTP_CONNECT_TIMEOUT);
+			requestFactory.setReadTimeout(RemoteJWKSet.DEFAULT_HTTP_READ_TIMEOUT);
+			setRequestFactory(requestFactory);
+		}
+
+	}
+
 	/**
 	 * A builder for creating {@link NimbusJwtDecoder} instances based on a public key.
 	 */