Return "431 Request Header Fields Too Large" for long headers on HTTP…

…/1 (#4655)

* Return "431 Request Header Fields Too Large" for long headers on HTTP/1

Motivation:

Netty HTTP/1 codec raises `TooLongHttpHeaderException` if headers exceed
the max length limit. However, `Http1RequestDecoder` does not take
account into `TooLongHttpLineException` and returns "400 Bad Request"
instead.

Modifications:

- Make `Http1RequestDecoder` return `431 Request Header Fields Too Large`
  if a Netty HttpRequest fails with `TooLongHttpHeaderException`

Result:

- "431 Request Header Fields Too Large" is now returned instead of
  `400 Bad Request` if the size of header exceeds
  `ServerBuilder.http1MaxHeaderSize()`.
- Fixes #4609

* Fix the error message

core/src/main/java/com/linecorp/armeria/server/Http1RequestDecoder.java

@@ -59,6 +59,7 @@
 import io.netty.handler.codec.http.HttpUtil;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http.LastHttpContent;
+import io.netty.handler.codec.http.TooLongHttpHeaderException;
 import io.netty.handler.codec.http.TooLongHttpLineException;
 import io.netty.handler.codec.http2.Http2CodecUtil;
 import io.netty.handler.codec.http2.Http2Error;
@@ -151,6 +152,9 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
                         final Throwable cause = nettyReq.decoderResult().cause();
                         if (cause instanceof TooLongHttpLineException) {
                             fail(id, null, HttpStatus.REQUEST_URI_TOO_LONG, "Too Long URI", cause);
+                        } else if (cause instanceof TooLongHttpHeaderException) {
+                            fail(id, null, HttpStatus.REQUEST_HEADER_FIELDS_TOO_LARGE,
+                                 "Request Header Fields Too Large", cause);
                         } else {
                             fail(id, null, HttpStatus.BAD_REQUEST, "Decoder failure", cause);
                         }

core/src/test/java/com/linecorp/armeria/server/LongHttp1HeadersTest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2023 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package com.linecorp.armeria.server;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import com.google.common.base.Strings;
+
+import com.linecorp.armeria.client.BlockingWebClient;
+import com.linecorp.armeria.common.AggregatedHttpResponse;
+import com.linecorp.armeria.common.HttpResponse;
+import com.linecorp.armeria.common.HttpStatus;
+import com.linecorp.armeria.common.SessionProtocol;
+import com.linecorp.armeria.testing.junit5.server.ServerExtension;
+
+class LongHttp1HeadersTest {
+
+    @RegisterExtension
+    static ServerExtension server = new ServerExtension() {
+        @Override
+        protected void configure(ServerBuilder sb) {
+            sb.http1MaxHeaderSize(100);
+
+            sb.service("/", (ctx, req) -> HttpResponse.of("OK"));
+        }
+    };
+
+    @Test
+    void shouldReturn431WithLongHeadersForHttp1() {
+        final BlockingWebClient client = BlockingWebClient.of(server.uri(SessionProtocol.H1C));
+        final AggregatedHttpResponse response = client.prepare()
+                                                      .get("/")
+                                                      .header("x-long", Strings.repeat("1", 100))
+                                                      .execute();
+        assertThat(response.status()).isEqualTo(HttpStatus.REQUEST_HEADER_FIELDS_TOO_LARGE);
+    }
+}