Clarify that requestHeaderSize is a cumulative limit (#7417)

* Clarify that requestHeaderSize is a cumulative limit

HttpConfiguration documents the requestHeaderSize configuration option
as being a limit on the size of a single request header, but it is in
fact a limit on the cumulative size of all request headers as well as
the request URI. This patch updates the documentation accordingly, and
adds test cases for the HTTP/1.x and HTTP/2 parsers to verify the
behavior.

NB.: the HTTP/3 parser and configuration seem to correctly document this
option as being a global limit on header size.

* Improve requestHeaderSize tests and documentation per review

Signed-off-by: Máté Szabó <mszabo@wikia-inc.com>

jetty-http/src/test/java/org/eclipse/jetty/http/HttpParserTest.java

@@ -2104,6 +2104,41 @@ public class HttpParserTest
         assertNull(_bad);
     }
 
+    @Test
+    public void testRequestMaxHeaderBytesURITooLong()
+    {
+        ByteBuffer buffer = BufferUtil.toBuffer(
+                "GET /long/nested/path/uri HTTP/1.1\r\n" +
+                "Host: example.com\r\n" +
+                "Connection: close\r\n" +
+                "\r\n");
+
+        int maxHeaderBytes = 5;
+        HttpParser.RequestHandler handler = new Handler();
+        HttpParser parser = new HttpParser(handler, maxHeaderBytes);
+
+        parseAll(parser, buffer);
+        assertEquals("414", _bad);
+    }
+
+    @Test
+    public void testRequestMaxHeaderBytesCumulative()
+    {
+        ByteBuffer buffer = BufferUtil.toBuffer(
+                "GET /nested/path/uri HTTP/1.1\r\n" +
+                "Host: example.com\r\n" +
+                "X-Large-Header: lorem-ipsum-dolor-sit\r\n" +
+                "Connection: close\r\n" +
+                "\r\n");
+
+        int maxHeaderBytes = 64;
+        HttpParser.RequestHandler handler = new Handler();
+        HttpParser parser = new HttpParser(handler, maxHeaderBytes);
+
+        parseAll(parser, buffer);
+        assertEquals("431", _bad);
+    }
+
     @Test
     @SuppressWarnings("ReferenceEquality")
     public void testCachedField()

jetty-http2/http2-common/src/test/java/org/eclipse/jetty/http2/frames/HeadersTooLargeParseTest.java

@@ -0,0 +1,96 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2021 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.http2.frames;
+
+import java.nio.ByteBuffer;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.UnaryOperator;
+
+import org.eclipse.jetty.http.HostPortHttpField;
+import org.eclipse.jetty.http.HttpFields;
+import org.eclipse.jetty.http.HttpScheme;
+import org.eclipse.jetty.http.HttpVersion;
+import org.eclipse.jetty.http.MetaData;
+import org.eclipse.jetty.http2.ErrorCode;
+import org.eclipse.jetty.http2.generator.HeaderGenerator;
+import org.eclipse.jetty.http2.generator.HeadersGenerator;
+import org.eclipse.jetty.http2.hpack.HpackEncoder;
+import org.eclipse.jetty.http2.hpack.HpackException;
+import org.eclipse.jetty.http2.parser.Parser;
+import org.eclipse.jetty.io.ByteBufferPool;
+import org.eclipse.jetty.io.MappedByteBufferPool;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class HeadersTooLargeParseTest
+{
+    private final ByteBufferPool byteBufferPool = new MappedByteBufferPool();
+
+    @Test
+    public void testProtocolErrorURITooLong() throws HpackException
+    {
+        HttpFields fields = HttpFields.build()
+                .put("B", "test");
+        MetaData.Request metaData = new MetaData.Request("GET", HttpScheme.HTTP.asString(), new HostPortHttpField("localhost:8080"), "/nested/uri/path/too/long", HttpVersion.HTTP_2, fields, -1);
+        int maxHeaderSize = 48;
+
+        assertProtocolError(maxHeaderSize, metaData);
+    }
+
+    @Test
+    public void testProtocolErrorCumulativeHeaderSize() throws HpackException
+    {
+        HttpFields fields = HttpFields.build()
+                .put("X-Large-Header", "lorem-ipsum-dolor-sit")
+                .put("X-Other-Header", "test");
+        MetaData.Request metaData = new MetaData.Request("GET", HttpScheme.HTTP.asString(), new HostPortHttpField("localhost:8080"), "/", HttpVersion.HTTP_2, fields, -1);
+        int maxHeaderSize = 64;
+
+        assertProtocolError(maxHeaderSize, metaData);
+    }
+
+    private void assertProtocolError(int maxHeaderSize, MetaData.Request metaData) throws HpackException
+    {
+        HeadersGenerator generator = new HeadersGenerator(new HeaderGenerator(), new HpackEncoder());
+
+        AtomicInteger failure = new AtomicInteger();
+        Parser parser = new Parser(byteBufferPool, new Parser.Listener.Adapter()
+        {
+            @Override
+            public void onConnectionFailure(int error, String reason)
+            {
+                failure.set(error);
+            }
+        }, 4096, maxHeaderSize);
+        parser.init(UnaryOperator.identity());
+
+        int streamId = 48;
+        ByteBufferPool.Lease lease = new ByteBufferPool.Lease(byteBufferPool);
+        PriorityFrame priorityFrame = new PriorityFrame(streamId, 3 * streamId, 200, true);
+        int len = generator.generateHeaders(lease, streamId, metaData, priorityFrame, true);
+
+        for (ByteBuffer buffer : lease.getByteBuffers())
+        {
+            while (buffer.hasRemaining() && failure.get() == 0)
+            {
+                parser.parse(buffer);
+            }
+        }
+
+        assertTrue(len > maxHeaderSize);
+        assertEquals(ErrorCode.PROTOCOL_ERROR.code, failure.get());
+    }
+}

jetty-server/src/main/java/org/eclipse/jetty/server/HttpConfiguration.java

@@ -193,7 +193,7 @@ public class HttpConfiguration implements Dumpable
         return _outputAggregationSize;
     }
 
-    @ManagedAttribute("The maximum allowed size in bytes for an HTTP request header")
+    @ManagedAttribute("The maximum allowed size in bytes for the HTTP request line and HTTP request headers")
     public int getRequestHeaderSize()
     {
         return _requestHeaderSize;
@@ -406,11 +406,13 @@ public class HttpConfiguration implements Dumpable
     }
 
     /**
+     * <p>Sets the maximum allowed size in bytes for the HTTP request line and HTTP request headers.</p>
+     *
      * <p>Larger headers will allow for more and/or larger cookies plus larger form content encoded
      * in a URL. However, larger headers consume more memory and can make a server more vulnerable to denial of service
      * attacks.</p>
      *
-     * @param requestHeaderSize the maximum size in bytes of the request header
+     * @param requestHeaderSize the maximum allowed size in bytes for the HTTP request line and HTTP request headers
      */
     public void setRequestHeaderSize(int requestHeaderSize)
     {