8263899: HttpClient throws NPE in AuthenticationFilter when parsing www-authenticate head

Reviewed-by: dfuchs, chegar

src/java.net.http/share/classes/jdk/internal/net/http/AuthenticationFilter.java

@@ -275,7 +275,7 @@ class AuthenticationFilter implements HeaderFilter {
         for (String aval : authvals) {
             HeaderParser parser = new HeaderParser(aval);
             String scheme = parser.findKey(0);
-            if (scheme.equalsIgnoreCase("Basic")) {
+            if (scheme != null && scheme.equalsIgnoreCase("Basic")) {
                 authval = aval;
                 var charset = parser.findValue("charset");
                 isUTF8 = (charset != null && charset.equalsIgnoreCase("UTF-8"));

test/jdk/java/net/httpclient/EmptyAuthenticate.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8263899
+ * @summary HttpClient throws NPE in AuthenticationFilter when parsing www-authenticate head
+ *
+ * @run main/othervm EmptyAuthenticate
+ */
+import com.sun.net.httpserver.HttpServer;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+
+public class EmptyAuthenticate {
+
+    public static void main(String[] args) throws IOException, URISyntaxException, InterruptedException {
+        int port = 0;
+
+        //start server:
+        HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);
+        port = server.getAddress().getPort();
+        server.createContext("/", exchange -> {
+            String response = "test body";
+            //this empty header will make the HttpClient throw NPE
+            exchange.getResponseHeaders().add("www-authenticate", "");
+            exchange.sendResponseHeaders(401, response.length());
+            OutputStream os = exchange.getResponseBody();
+            os.write(response.getBytes());
+            os.close();
+        });
+        server.start();
+
+        HttpResponse<String> response = null;
+        //run client:
+        try {
+            HttpClient httpClient = HttpClient.newHttpClient();
+            HttpRequest request = HttpRequest.newBuilder(new URI("http://localhost:" + port + "/")).GET().build();
+            //this line will throw NPE (wrapped by IOException) when parsing empty www-authenticate response header in AuthenticationFilter:
+            response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+            boolean ok = !response.headers().firstValue("WWW-Authenticate").isEmpty();
+            if (!ok) {
+                throw new RuntimeException("WWW-Authenicate missing");
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+            throw new RuntimeException("Test failed");
+        } finally {
+            server.stop(0);
+        }
+    }
+}