Remove content-length header leniency

Motivation:

If the content-length does not parse as a number, leniency causes this
to instead be parsed as the default value. This leads to bodies being
silently ignored on requests which can be incredibly dangerous. Instead,
if the content-length header is invalid, an exception should be thrown
for upstream handling.

Modifications:

This commit removes the leniency in parsing the content-length header by
allowing a number format exception, if thrown, to escape from the method
rather than falling back to the default value.

Result:

In invalid content-length header will not be silently ignored.

codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectAggregator.java

@@ -151,7 +151,11 @@ public class HttpObjectAggregator
 
     @Override
     protected boolean isContentLengthInvalid(HttpMessage start, int maxContentLength) {
-        return getContentLength(start, -1L) > maxContentLength;
+        try {
+            return getContentLength(start, -1L) > maxContentLength;
+        } catch (final NumberFormatException e) {
+            return false;
+        }
     }
 
     @Override

codec-http/src/main/java/io/netty/handler/codec/http/HttpUtil.java

@@ -172,23 +172,19 @@ public final class HttpUtil {
     }
 
     /**
-     * Returns the length of the content. Please note that this value is
-     * not retrieved from {@link HttpContent#content()} but from the
-     * {@code "Content-Length"} header, and thus they are independent from each
-     * other.
+     * Returns the length of the content or the specified default value if the message does not have the {@code
+     * "Content-Length" header}. Please note that this value is not retrieved from {@link HttpContent#content()} but
+     * from the {@code "Content-Length"} header, and thus they are independent from each other.
      *
-     * @return the content length or {@code defaultValue} if this message does
-     *         not have the {@code "Content-Length"} header or its value is not
-     *         a number
+     * @param message      the message
+     * @param defaultValue the default value
+     * @return the content length or the specified default value
+     * @throws NumberFormatException if the {@code "Content-Length"} header does not parse as a long
      */
     public static long getContentLength(HttpMessage message, long defaultValue) {
         String value = message.headers().get(HttpHeaderNames.CONTENT_LENGTH);
         if (value != null) {
-            try {
-                return Long.parseLong(value);
-            } catch (NumberFormatException ignore) {
-                return defaultValue;
-            }
+            return Long.parseLong(value);
         }
 
         // We know the content length if it's a Web Socket message even if

codec-http/src/test/java/io/netty/handler/codec/http/HttpUtilTest.java

@@ -25,10 +25,14 @@ import java.util.Collections;
 import java.util.List;
 
 import static io.netty.handler.codec.http.HttpHeadersTestUtils.of;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.hasToString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class HttpUtilTest {
 
@@ -130,12 +134,39 @@ public class HttpUtilTest {
     }
 
     @Test
-    public void testGetContentLengthDefaultValue() {
-        HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
-        assertNull(message.headers().get(HttpHeaderNames.CONTENT_LENGTH));
+    public void testGetContentLengthThrowsNumberFormatException() {
+        final HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
         message.headers().set(HttpHeaderNames.CONTENT_LENGTH, "bar");
-        assertEquals("bar", message.headers().get(HttpHeaderNames.CONTENT_LENGTH));
-        assertEquals(1L, HttpUtil.getContentLength(message, 1L));
+        try {
+            HttpUtil.getContentLength(message);
+            fail();
+        } catch (final NumberFormatException e) {
+            // a number format exception is expected here
+        }
+    }
+
+    @Test
+    public void testGetContentLengthIntDefaultValueThrowsNumberFormatException() {
+        final HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
+        message.headers().set(HttpHeaderNames.CONTENT_LENGTH, "bar");
+        try {
+            HttpUtil.getContentLength(message, 1);
+            fail();
+        } catch (final NumberFormatException e) {
+            // a number format exception is expected here
+        }
+    }
+
+    @Test
+    public void testGetContentLengthLongDefaultValueThrowsNumberFormatException() {
+        final HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
+        message.headers().set(HttpHeaderNames.CONTENT_LENGTH, "bar");
+        try {
+            HttpUtil.getContentLength(message, 1L);
+            fail();
+        } catch (final NumberFormatException e) {
+            // a number format exception is expected here
+        }
     }
 
     @Test