From e21591fa251144f39d108deeee9508e470dbb713 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Thu, 26 Aug 2021 08:20:17 +0200
Subject: [PATCH] Don't throw if null is given as ByteBuf when adding
 components. (#11613)

Motivation:

232c669fa413a9079ee6216056b57a647143f4b6 did add some overflow protection but did not handle null elements in the array the same as before.

Modifications:

- Break the loop if a null element was found
- Add unit test

Result:

Fixes https://github.com/netty/netty/issues/11612
---
 .../java/io/netty/buffer/CompositeByteBuf.java     |  6 +++++-
 .../netty/buffer/AbstractCompositeByteBufTest.java | 14 ++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java b/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java
index 1cde1fff8e..8a32dd27ac 100644
--- a/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java
+++ b/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java
@@ -374,7 +374,11 @@ public class CompositeByteBuf extends AbstractReferenceCountedByteBuf implements
         int readableBytes = 0;
         int capacity = capacity();
         for (int i = arrOffset; i < buffers.length; i++) {
-            readableBytes += buffers[i].readableBytes();
+            ByteBuf b = buffers[i];
+            if (b == null) {
+                break;
+            }
+            readableBytes += b.readableBytes();
 
             // Check if we would overflow.
             // See https://github.com/netty/netty/issues/10194
diff --git a/buffer/src/test/java/io/netty/buffer/AbstractCompositeByteBufTest.java b/buffer/src/test/java/io/netty/buffer/AbstractCompositeByteBufTest.java
index 3d88df0cdf..8d84d12b77 100644
--- a/buffer/src/test/java/io/netty/buffer/AbstractCompositeByteBufTest.java
+++ b/buffer/src/test/java/io/netty/buffer/AbstractCompositeByteBufTest.java
@@ -1555,6 +1555,20 @@ public abstract class AbstractCompositeByteBufTest extends AbstractByteBufTest {
         assertTrue(cbuf.release());
     }
 
+    // See https://github.com/netty/netty/issues/11612
+    @Test
+    public void testAddComponentWithNullEntry() {
+        final ByteBuf buffer = Unpooled.buffer(8).writeZero(8);
+        final CompositeByteBuf compositeByteBuf = compositeBuffer(Integer.MAX_VALUE);
+        try {
+            compositeByteBuf.addComponents(true, new ByteBuf[] { buffer, null });
+            assertEquals(8, compositeByteBuf.readableBytes());
+            assertEquals(1, compositeByteBuf.numComponents());
+        } finally {
+            compositeByteBuf.release();
+        }
+    }
+
     @Test
     public void testOverflowWhileAddingComponent() {
         int capacity = 1024 * 1024; // 1MB