[Bug] NullPointerException in AdminBrokerProcessor.updateAndCreateTopicList at line 636

[UnZHGPPT]

Before Creating the Bug Report

• I found a bug, not just asking a question, which should be created in GitHub Discussions.

• I have searched the GitHub Issues and GitHub Discussions of this repository and believe that this is not a duplicate.

• I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

Runtime platform environment

OS name: "linux", version: "5.15.0-138-generic", arch: "amd64", family: "unix"

RocketMQ version

version: rocketmq-all-5.4.0
link: https://github.com/apache/rocketmq/archive/refs/tags/rocketmq-all-5.4.0.zip

JDK Version

Java version: 1.8.0_452
Build tool: Apache Maven 3.9.1

Describe the Bug

A NullPointerException occurs when invoking AdminBrokerProcessor.processRequest with a RemotingCommand created via RemotingCommand.createRequestCommand(...) that has a null body. The issue arises because the method CreateTopicListRequestBody.decode(...) returns null when the input byte array is null, and the subsequent call to requestBody.getTopicConfigList() dereferences this null value.

Steps to Reproduce

Test Code:

package org.apache.rocketmq.broker.processor;
import org.apache.rocketmq.broker.processor.AdminBrokerProcessor;
import org.junit.Test;
import org.apache.rocketmq.broker.BrokerController;
import io.netty.channel.ChannelHandlerContext;
import org.apache.rocketmq.remoting.protocol.RemotingCommand;
import org.apache.rocketmq.remoting.protocol.RequestCode;
import org.apache.rocketmq.common.BrokerConfig;
import org.apache.rocketmq.common.MixAll;
import org.apache.rocketmq.remoting.netty.NettyClientConfig;
import org.apache.rocketmq.remoting.netty.NettyServerConfig;
import org.apache.rocketmq.store.config.MessageStoreConfig;

public class TestClass {
    @Test(timeout=3000)
    public void test() throws Throwable {
        BrokerConfig brokerConfig = new BrokerConfig();
        NettyServerConfig nettyServerConfig = new NettyServerConfig();
        NettyClientConfig nettyClientConfig = new NettyClientConfig();
        MessageStoreConfig messageStoreConfig = new MessageStoreConfig();
        BrokerController brokerController = new BrokerController(brokerConfig, nettyServerConfig, nettyClientConfig, messageStoreConfig);
        AdminBrokerProcessor adminBrokerProcessor0 = new AdminBrokerProcessor(brokerController);
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.UPDATE_AND_CREATE_TOPIC_LIST, null);
        adminBrokerProcessor0.processRequest((ChannelHandlerContext) null, request);
    }
}

Execution Result:

JUnit version 4.13.2
.E
Time: 0.869
There was 1 failure:
1) test(org.apache.rocketmq.broker.processor.TestClass)
java.lang.NullPointerException
	at org.apache.rocketmq.broker.processor.AdminBrokerProcessor.updateAndCreateTopicList(AdminBrokerProcessor.java:636)
	at org.apache.rocketmq.broker.processor.AdminBrokerProcessor.processRequest(AdminBrokerProcessor.java:269)
	at org.apache.rocketmq.broker.processor.TestClass.test(TestClass.java:24)

FAILURES!!!
Tests run: 1,  Failures: 1

What Did You Expect to See?

The method should either:

• Validate that the request body is non-null before decoding, or
• Handle the case where the decoded CreateTopicListRequestBody is null gracefully (e.g., return an error response).

What Did You See Instead?

A NPE is thrown:

java.lang.NullPointerException
    at org.apache.rocketmq.broker.processor.AdminBrokerProcessor.updateAndCreateTopicList(AdminBrokerProcessor.java:636)
    at org.apache.rocketmq.broker.processor.AdminBrokerProcessor.processRequest(AdminBrokerProcessor.java:269)
    at org.apache.rocketmq.broker.processor.TestClass.test(TestClass.java:24)

Additional Context

Root Cause Analysis

1. RemotingCommand.createRequestCommand(...) does not initialize the body field.

2. In updateAndCreateTopicList, the code calls:

final CreateTopicListRequestBody requestBody = CreateTopicListRequestBody.decode(request.getBody(), CreateTopicListRequestBody.class);

Since request.getBody() returns null, decode(...) returns null.

3. The next line unconditionally accesses:

List<TopicConfig> topicConfigList = requestBody.getTopicConfigList(); // NPE here